This document summarizes research on using iron-based catalysts containing a second metal like magnesium or molybdenum for direct coal liquefaction. The key points are:
1) Iron-based catalysts containing magnesium or molybdenum as a second metal were tested for direct coal liquefaction.
2) Molybdenum increased catalyst activity the most, resulting in over 90% coal conversion at 400°C. Oil yields also increased significantly with molybdenum.
3) Tetralin and phenanthrene were used as solvents, with catalytic effects being more evident using phenanthrene as it is a poorer hydrogen donor.
Removal of Coke during Steam Reforming of Ethanol over La-CoOx Catalystinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Simulation of Flash Pyrolysis of Maiganga Coal Using Modified Straight First ...Premier Publishers
Maiganga coal is a coal deposit discovered some years back in Maiganga village, Gombe State, Nigeria; the coal is yet to be exploited. The paper presents simulation of destructive distillation of the coal. The coal and kinetics data were collected from literature. The straight first order reaction, (SFOR) model was modified to accommodate the effects of pyrolysis reactor power. The straight first order reaction model was coded in Microsoft excel. The kinetics and coal data collected were used to simulate the destructive distillation of the coal. Effects of temperature, heat rate, and residence time were investigated on the volatile matters yield. The outcome of the simulation shows that 550 to 650 oC is the range of temperature at which more volatile matter is generated. Between this ranges of temperature, more than 90% of volatile matters are generated at residence time of 2 hours. Heat rate was found to affect volatile matters yield. The maximum vapour generation was obtained between 50 to 100 oC/min.
Effect of Solvent Swelling on the reactivity of demineralized Turkish LigniteIJERA Editor
In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.
This document summarizes research on converting lignin into liquid compounds through a solvolysis (alcoholysis) process. Lignin was heated to 270-300°C with an alcohol and acid in a high-pressure reactor. Key results include:
- Formic acid produced the highest pressures and yields of phenolic compounds, while acetic acid yielded mainly esters.
- Gas chromatography/mass spectrometry analysis showed the main products with formic acid were phenolic compounds, while acetic acid yielded esters like ethyl acetate and isopropyl acetate.
- Temperature reached 300°C within 75-90 minutes and pressure was regulated to not exceed 200 bars.
So in summary, this
The document discusses unexpected results from treating MgCl2-supported polypropylene catalysts containing organometallic complexes with additional TiCl4. Adding TiCl4 at a level equal to the existing Ti increased catalyst activity by 70-95% and decreased the polymer melt flow rate by 50%, suggesting a two-component catalyst system. The author proposes the TiCl4 treatment replaces the organometallic complex and frees it to take an external role while restoring the original MgCl2/TiCl4 catalyst. This two-component system provides roughly equal contributions to activity from each component but differing effects on polymer properties like extractables. The author also suggests these complexes could be converted to single-site catalysts using reactive
1. Alkanes undergo combustion reactions where they burn with oxygen to produce carbon dioxide and water. They also undergo substitution reactions with halogens.
2. Long chain alkanes found in petroleum can be cracked into shorter chain alkanes and alkenes through thermal cracking. Short chain alkanes are used as fuels and alkenes are used to make polymers.
3. Halogenated alkanes have various uses such as anesthetics, refrigerants, and cleaning agents. However, some refrigerants damage the ozone layer. Alkanes also have economic importance as they can be used to produce synthesis gas and divided carbon through thermal reactions.
The document discusses the Ziegler-Natta catalyst, which is an important class of chemical compounds that can polymerize olefins like ethylene and propylene into high molecular weight polymers with stereoregular structures. It describes how Karl Zeigler developed catalysts in 1953 that produced polyethylene with high molecular weight and Natta further developed the methodology in 1954. Zeigler and Natta were jointly awarded the Nobel Prize in 1963. The mechanism of the Ziegler-Natta catalyst involves the formation of a complex between titanium and aluminum that allows for the insertion of monomer units between titanium and an ethyl group to stereospecifically form isotactic polymers.
Removal of Coke during Steam Reforming of Ethanol over La-CoOx Catalystinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Simulation of Flash Pyrolysis of Maiganga Coal Using Modified Straight First ...Premier Publishers
Maiganga coal is a coal deposit discovered some years back in Maiganga village, Gombe State, Nigeria; the coal is yet to be exploited. The paper presents simulation of destructive distillation of the coal. The coal and kinetics data were collected from literature. The straight first order reaction, (SFOR) model was modified to accommodate the effects of pyrolysis reactor power. The straight first order reaction model was coded in Microsoft excel. The kinetics and coal data collected were used to simulate the destructive distillation of the coal. Effects of temperature, heat rate, and residence time were investigated on the volatile matters yield. The outcome of the simulation shows that 550 to 650 oC is the range of temperature at which more volatile matter is generated. Between this ranges of temperature, more than 90% of volatile matters are generated at residence time of 2 hours. Heat rate was found to affect volatile matters yield. The maximum vapour generation was obtained between 50 to 100 oC/min.
Effect of Solvent Swelling on the reactivity of demineralized Turkish LigniteIJERA Editor
In this research, effect of demineralization and solvent swelling on pyrolysis kinetics was investigated. The experiments were carried out to investigate theeffects of solvent swelling with different solvents, such as THF, Pyridine and DMSO after demineralization with HCl, HNO3 and HF successively. To calculate the activation energies of lignite sample during pyrolysis, TGA analyses were performed with raw and swollen samples at 5, 10 and 20° C/min heating rates. Coast-Redfernmodel was used for the determination of kinetic parameters. According to the results, the macromolecular structure of lignite was affected from these hydrogen bonding solvents. So, the activation energies of swollen samples found to be less than the raw lignite sample for all heating rates. The reactivity of lignite samples can be ordered as follows; DMSO swollen sample > Pyridine swollen sample> THF swollen sample. Activation energy of DMSO swollen lignite sample is 10.62 kJ/mole whereas activation energies of pyridine swollen and THF swollen sample are 17.83, 25.76 kJ/mol, respectively at a heating rate of 10° C/min. The results indicated that, solvent swelling has catalytic effect on pyrolysis kinetics.
This document summarizes research on converting lignin into liquid compounds through a solvolysis (alcoholysis) process. Lignin was heated to 270-300°C with an alcohol and acid in a high-pressure reactor. Key results include:
- Formic acid produced the highest pressures and yields of phenolic compounds, while acetic acid yielded mainly esters.
- Gas chromatography/mass spectrometry analysis showed the main products with formic acid were phenolic compounds, while acetic acid yielded esters like ethyl acetate and isopropyl acetate.
- Temperature reached 300°C within 75-90 minutes and pressure was regulated to not exceed 200 bars.
So in summary, this
The document discusses unexpected results from treating MgCl2-supported polypropylene catalysts containing organometallic complexes with additional TiCl4. Adding TiCl4 at a level equal to the existing Ti increased catalyst activity by 70-95% and decreased the polymer melt flow rate by 50%, suggesting a two-component catalyst system. The author proposes the TiCl4 treatment replaces the organometallic complex and frees it to take an external role while restoring the original MgCl2/TiCl4 catalyst. This two-component system provides roughly equal contributions to activity from each component but differing effects on polymer properties like extractables. The author also suggests these complexes could be converted to single-site catalysts using reactive
1. Alkanes undergo combustion reactions where they burn with oxygen to produce carbon dioxide and water. They also undergo substitution reactions with halogens.
2. Long chain alkanes found in petroleum can be cracked into shorter chain alkanes and alkenes through thermal cracking. Short chain alkanes are used as fuels and alkenes are used to make polymers.
3. Halogenated alkanes have various uses such as anesthetics, refrigerants, and cleaning agents. However, some refrigerants damage the ozone layer. Alkanes also have economic importance as they can be used to produce synthesis gas and divided carbon through thermal reactions.
The document discusses the Ziegler-Natta catalyst, which is an important class of chemical compounds that can polymerize olefins like ethylene and propylene into high molecular weight polymers with stereoregular structures. It describes how Karl Zeigler developed catalysts in 1953 that produced polyethylene with high molecular weight and Natta further developed the methodology in 1954. Zeigler and Natta were jointly awarded the Nobel Prize in 1963. The mechanism of the Ziegler-Natta catalyst involves the formation of a complex between titanium and aluminum that allows for the insertion of monomer units between titanium and an ethyl group to stereospecifically form isotactic polymers.
Effect of cu co mixed metal oxides on the combustion of psan-htpb based solid...eSAT Journals
Abstract Composite propellants based on ammonium perchlorate (AP) as oxidizer are state-of-the-art. However, global environmental impact restricts AP-based propellants because of their high chlorine exhaust. Therefore, efforts are on to innovate propellants with clean exhaust. Ammonium nitrate (AN) has, thus, regained importance in the field of propellants and explosives, more specifically in insensitive formulations, because of its clean burning and low hazard. However, the stumbling block for the application of AN - as solid propellant oxidizer has been its dimensional instability caused by phase transformation which results in increase of volume and porosity of the propellant grain. This can be overcome by the use of phase stabilized ammonium nitrate (PSAN). In the present study AN phase stabilized by incorporating 10% KN to prepare composite solid propellant. Copper-Cobalt mixed metal oxides have been synthesized via citric acid complexing method. Three different catalysts were prepared with different Cu-Co molar ratios 1, 0.5 And 2 in the initial reactants. The synthesized catalysts were then added to the PSAN-HTPB(Phase Stabilized Ammonium Nitrate- Hydroxyl Terminated Poly-Butadiene) composite formulations. These propellant samples were subjected to burn rate measurement in a Crawford High Pressure Strand Burner and thermal degradation studies in Simultaneous Thermal Analyzer (STA). The thermal decomposition and burn rate of the propellant is observed maximum on the addition of Copper-Cobalt mixed metal oxide catalyst with molar ratio 2. A total of six propellant samples catalyzed and non-catalyzed and one preheated virgin sample were undertaken for the above analysis and results obtained are discussed. It has been observed that except the propellant sample with Cu-Co-III and virgin propellant where PSAN was prepared by solid mixing, other propellant samples were hard to burn. KeyWords:Solid propellants, Ammonium nitrate, Phase stabilization, Burn rate, Thermal decomposition, Mixed metal oxides, Catalytic combustion.
Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an ef...Pawan Kumar
Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt
phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding
disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of
mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external
magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4
support prevents the leaching of the catalyst and improves its activity and stability
The document analyzes the effects of high-temperature pyrolysis between 1000°C-1600°C on the structure and properties of coal char and petroleum coke. Results showed that the carbon crystallite structure of both materials became more ordered with increasing temperature, though coal char's graphitization was lower. BET surface area, gasification reactivity, powder resistivity, and real density changed differently for coal char and petroleum coke with increasing pyrolysis temperature. The study provides insights into the differences between coal char and petroleum coke properties after high-temperature treatment to help substitute coal char for petroleum coke in producing carbon anodes.
This document provides an overview of homogeneous catalysis and biocatalysis. It discusses various homogeneous catalysts including Wilkinson's catalyst, Ziegler-Natta catalysts, and catalysts used in hydrogenation and hydroformylation reactions. It also discusses the use of enzymes in organic synthesis, including hydrolysis reactions and the synthesis of tartaric acids. Finally, it covers immobilized enzymes and various methods for enzyme immobilization.
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The identification of photo-oxidation products and their quantitative determination was done using GC-MS. After completion of the reaction, the catalyst was easily recovered by filtration and reused for several runs without loss in activity and no leaching was observed during the reaction.
The document discusses various methods for modifying solid acids like zeolites to increase the selectivity and yield of p-xylene in toluene methylation reactions. Silylation of zeolites using compounds like TEOS reduces pore size and external acid sites. Loading metals like Mg, La, and Pt improves stability and selectivity. Using co-crystalline zeolites or superacids supported on clays also enhances p-xylene production. Reaction conditions like lower contact times below 0.1 seconds and suitable binders maximize selectivity.
AQA A-Level Chemistry New Spec: Alkanes and related ProcessesJonti Cole
Alkanes are organic compounds made of carbon and hydrogen. They have general formula CnH2n+2 and are saturated hydrocarbons. Alkanes can be unbranched chains, branched chains, or cyclic rings. They have low reactivity but can undergo combustion to produce water and carbon dioxide. Fractional distillation and catalytic/thermal cracking are used to separate crude oil and produce fuels.
A ruthenium-carbamato-complex derived from a siloxylated amine and carbon dio...Pawan Kumar
The rutheniumcarbamate complex derived from3-trimethoxysilyl-1-
propyl amine and carbon dioxidewas found to be a novel catalyst for
the oxidative cyanation of aromatic and cyclic tertiary amines to
corresponding a-amino nitriles in high to excellent yields by using
hydrogen peroxide and molecular oxygen as enviro-economic
oxidants. The developed protocol suggested an efficient alternative
for recycling carbon dioxide.
This study investigated the inhibition of copper corrosion in nitric acid solution by 3-arylazotriazole compounds (AT). Potentiodynamic polarization and Tafel methods showed that AT compounds were good inhibitors. The inhibition effect is likely due to adsorption of AT molecules and formation of Cu(II)-AT complexes on the electrode surface. Higher AT concentrations achieved over 95% inhibition efficiency. Temperature increased corrosion rates by enhancing desorption and surface reactions. UV-Vis spectroscopy and cyclic voltammetry supported the formation of Cu(II)-AT complexes in solution.
Group transfer polymerization (GTP) is a "quasi-living" polymerization technique that allows controlled polymerization of monomers like methacrylates. GTP uses silyl ketene acetal initiators and metal-free catalysts. Propagation occurs via Michael addition, transferring the silyl group to the added monomer. While initially thought to proceed via an associative mechanism, evidence supports a dissociative mechanism. GTP produces polymers with controlled molecular weight and can create block copolymers, random copolymers, and other architectures. Applications include dispersing agents for water-based inks.
Alkanes undergo two main types of chemical reactions: substitution reactions and thermal/catalytic reactions. Substitution reactions involve replacing one or more hydrogen atoms with other atoms or groups. The main substitution reactions are halogenation, nitration, sulphonation, and chlorosulphonation. Thermal and catalytic reactions involve heat and catalysts and include oxidation, pyrolysis, isomerization, and aromatization. Alkanes are industrially important as fuels and in producing other chemicals through these various reaction pathways.
Catalytic Upgrading of Methane to Higher Hydrocarbon in a Non-oxidative Chemi...Shaima Nahreen
This document discusses catalytic upgrading of methane to higher hydrocarbons using ruthenium catalysts. Ruthenium supported on zeolite ZSM-5 catalysts showed higher methane conversion compared to ruthenium supported on silica. With 3% ruthenium on ZSM-5, methane conversion increased above 700°C producing hydrocarbons from C4 to C10. This catalyst also produced some aromatic compounds. Ruthenium supported on ZSM-5 was found to produce methyl radicals and lower the activation energy of methane more than ruthenium supported on silica based on density functional theory analyses.
Alkanes are saturated hydrocarbons with only carbon-carbon single bonds. Their general formula is CnH2n+2. Alkanes have low reactivity due to strong C-C and C-H bonds. They undergo combustion, producing carbon dioxide and water. In the presence of light, alkanes undergo substitution reactions with halogens like chlorine. Alkanes find many uses depending on their carbon number, such as fuels, solvents, polymers, and paraffin wax. Natural gas and petroleum contain alkanes that are crucial energy resources.
This document summarizes a dissertation submitted by Nur Fatin Dariah binti Mohamad Daud in partial fulfillment of the requirements for a Bachelor of Engineering (Hons) in Chemical Engineering at Universiti Teknologi PETRONAS in September 2015. The dissertation investigates the aqueous phase reforming of sorbitol over supported Ni/Alumina catalysts promoted with calcium. Various characterization techniques such as TGA, SEM, and H2-TPR were used to analyze the catalysts. The catalytic activity tests were carried out in a batch reactor to identify the value-added chemicals produced from sorbitol, which were analyzed using GCMS and HPLC. The addition of the cheap promoter calcium was studied
Alkanes are hydrocarbons composed of carbon and hydrogen. Methane (CH4) is the simplest alkane. Alkanes form homologous series with the general formula CnH2n+2. They have single bonds between carbon atoms arranged in an open chain or branched chain. Methane is a colorless, odorless gas found in natural gas deposits. It burns with an invisible flame. Ethane (C2H6) is the second simplest alkane and is also a colorless, odorless gas obtained from petroleum. It is used to produce ethylene and other chemicals.
Development of Mesoporous Materials and Noble Metal Based Hydrodesulfurizatio...Lebong Andalaluna
The document discusses the development of mesoporous materials and noble metal-based hydrodesulfurization catalysts. It was found that Pt supported on acidic mesoporous materials like SiAlMCM-41 showed high catalytic activity for thiophene hydrodesulfurization that was higher than commercial CoMo/Al2O3 catalysts. Pt supported on moderately acidic SiAlMCM-41 (Si/Al=15) exhibited particularly high activity. The acidic properties of the MCM-41 support and the spillover hydrogen on Pt particles in Pt/MCM-41 catalysts were found to play an important role in thiophene hydrodesulfurization.
Alkanes are hydrocarbons composed of only carbon and hydrogen linked by single bonds. They belong to a homologous series with a general formula of CnH2n+2. Common alkanes include methane, ethane, propane, butane, pentane, and hexane. Alkanes have many uses including heating, electricity generation, cooking, polymers, gasoline components, paraffin wax, and as intermediates to make other chemicals. Their applications depend on the number of carbon atoms, with shorter alkanes like methane used for energy and longer ones components of fuels, lubricants, and polymers.
Maiyalagan,Electrochemical oxidation of methanol on pt v2 o5–c composite cata...kutty79
Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic
acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron
microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using
cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode
show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities
and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes
being poisoned.
Effect of cu co mixed metal oxides on the combustion of psan-htpb based solid...eSAT Journals
Abstract Composite propellants based on ammonium perchlorate (AP) as oxidizer are state-of-the-art. However, global environmental impact restricts AP-based propellants because of their high chlorine exhaust. Therefore, efforts are on to innovate propellants with clean exhaust. Ammonium nitrate (AN) has, thus, regained importance in the field of propellants and explosives, more specifically in insensitive formulations, because of its clean burning and low hazard. However, the stumbling block for the application of AN - as solid propellant oxidizer has been its dimensional instability caused by phase transformation which results in increase of volume and porosity of the propellant grain. This can be overcome by the use of phase stabilized ammonium nitrate (PSAN). In the present study AN phase stabilized by incorporating 10% KN to prepare composite solid propellant. Copper-Cobalt mixed metal oxides have been synthesized via citric acid complexing method. Three different catalysts were prepared with different Cu-Co molar ratios 1, 0.5 And 2 in the initial reactants. The synthesized catalysts were then added to the PSAN-HTPB(Phase Stabilized Ammonium Nitrate- Hydroxyl Terminated Poly-Butadiene) composite formulations. These propellant samples were subjected to burn rate measurement in a Crawford High Pressure Strand Burner and thermal degradation studies in Simultaneous Thermal Analyzer (STA). The thermal decomposition and burn rate of the propellant is observed maximum on the addition of Copper-Cobalt mixed metal oxide catalyst with molar ratio 2. A total of six propellant samples catalyzed and non-catalyzed and one preheated virgin sample were undertaken for the above analysis and results obtained are discussed. It has been observed that except the propellant sample with Cu-Co-III and virgin propellant where PSAN was prepared by solid mixing, other propellant samples were hard to burn. KeyWords:Solid propellants, Ammonium nitrate, Phase stabilization, Burn rate, Thermal decomposition, Mixed metal oxides, Catalytic combustion.
Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an ef...Pawan Kumar
Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt
phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding
disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of
mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external
magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4
support prevents the leaching of the catalyst and improves its activity and stability
The document analyzes the effects of high-temperature pyrolysis between 1000°C-1600°C on the structure and properties of coal char and petroleum coke. Results showed that the carbon crystallite structure of both materials became more ordered with increasing temperature, though coal char's graphitization was lower. BET surface area, gasification reactivity, powder resistivity, and real density changed differently for coal char and petroleum coke with increasing pyrolysis temperature. The study provides insights into the differences between coal char and petroleum coke properties after high-temperature treatment to help substitute coal char for petroleum coke in producing carbon anodes.
This document provides an overview of homogeneous catalysis and biocatalysis. It discusses various homogeneous catalysts including Wilkinson's catalyst, Ziegler-Natta catalysts, and catalysts used in hydrogenation and hydroformylation reactions. It also discusses the use of enzymes in organic synthesis, including hydrolysis reactions and the synthesis of tartaric acids. Finally, it covers immobilized enzymes and various methods for enzyme immobilization.
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The identification of photo-oxidation products and their quantitative determination was done using GC-MS. After completion of the reaction, the catalyst was easily recovered by filtration and reused for several runs without loss in activity and no leaching was observed during the reaction.
The document discusses various methods for modifying solid acids like zeolites to increase the selectivity and yield of p-xylene in toluene methylation reactions. Silylation of zeolites using compounds like TEOS reduces pore size and external acid sites. Loading metals like Mg, La, and Pt improves stability and selectivity. Using co-crystalline zeolites or superacids supported on clays also enhances p-xylene production. Reaction conditions like lower contact times below 0.1 seconds and suitable binders maximize selectivity.
AQA A-Level Chemistry New Spec: Alkanes and related ProcessesJonti Cole
Alkanes are organic compounds made of carbon and hydrogen. They have general formula CnH2n+2 and are saturated hydrocarbons. Alkanes can be unbranched chains, branched chains, or cyclic rings. They have low reactivity but can undergo combustion to produce water and carbon dioxide. Fractional distillation and catalytic/thermal cracking are used to separate crude oil and produce fuels.
A ruthenium-carbamato-complex derived from a siloxylated amine and carbon dio...Pawan Kumar
The rutheniumcarbamate complex derived from3-trimethoxysilyl-1-
propyl amine and carbon dioxidewas found to be a novel catalyst for
the oxidative cyanation of aromatic and cyclic tertiary amines to
corresponding a-amino nitriles in high to excellent yields by using
hydrogen peroxide and molecular oxygen as enviro-economic
oxidants. The developed protocol suggested an efficient alternative
for recycling carbon dioxide.
This study investigated the inhibition of copper corrosion in nitric acid solution by 3-arylazotriazole compounds (AT). Potentiodynamic polarization and Tafel methods showed that AT compounds were good inhibitors. The inhibition effect is likely due to adsorption of AT molecules and formation of Cu(II)-AT complexes on the electrode surface. Higher AT concentrations achieved over 95% inhibition efficiency. Temperature increased corrosion rates by enhancing desorption and surface reactions. UV-Vis spectroscopy and cyclic voltammetry supported the formation of Cu(II)-AT complexes in solution.
Group transfer polymerization (GTP) is a "quasi-living" polymerization technique that allows controlled polymerization of monomers like methacrylates. GTP uses silyl ketene acetal initiators and metal-free catalysts. Propagation occurs via Michael addition, transferring the silyl group to the added monomer. While initially thought to proceed via an associative mechanism, evidence supports a dissociative mechanism. GTP produces polymers with controlled molecular weight and can create block copolymers, random copolymers, and other architectures. Applications include dispersing agents for water-based inks.
Alkanes undergo two main types of chemical reactions: substitution reactions and thermal/catalytic reactions. Substitution reactions involve replacing one or more hydrogen atoms with other atoms or groups. The main substitution reactions are halogenation, nitration, sulphonation, and chlorosulphonation. Thermal and catalytic reactions involve heat and catalysts and include oxidation, pyrolysis, isomerization, and aromatization. Alkanes are industrially important as fuels and in producing other chemicals through these various reaction pathways.
Catalytic Upgrading of Methane to Higher Hydrocarbon in a Non-oxidative Chemi...Shaima Nahreen
This document discusses catalytic upgrading of methane to higher hydrocarbons using ruthenium catalysts. Ruthenium supported on zeolite ZSM-5 catalysts showed higher methane conversion compared to ruthenium supported on silica. With 3% ruthenium on ZSM-5, methane conversion increased above 700°C producing hydrocarbons from C4 to C10. This catalyst also produced some aromatic compounds. Ruthenium supported on ZSM-5 was found to produce methyl radicals and lower the activation energy of methane more than ruthenium supported on silica based on density functional theory analyses.
Alkanes are saturated hydrocarbons with only carbon-carbon single bonds. Their general formula is CnH2n+2. Alkanes have low reactivity due to strong C-C and C-H bonds. They undergo combustion, producing carbon dioxide and water. In the presence of light, alkanes undergo substitution reactions with halogens like chlorine. Alkanes find many uses depending on their carbon number, such as fuels, solvents, polymers, and paraffin wax. Natural gas and petroleum contain alkanes that are crucial energy resources.
This document summarizes a dissertation submitted by Nur Fatin Dariah binti Mohamad Daud in partial fulfillment of the requirements for a Bachelor of Engineering (Hons) in Chemical Engineering at Universiti Teknologi PETRONAS in September 2015. The dissertation investigates the aqueous phase reforming of sorbitol over supported Ni/Alumina catalysts promoted with calcium. Various characterization techniques such as TGA, SEM, and H2-TPR were used to analyze the catalysts. The catalytic activity tests were carried out in a batch reactor to identify the value-added chemicals produced from sorbitol, which were analyzed using GCMS and HPLC. The addition of the cheap promoter calcium was studied
Alkanes are hydrocarbons composed of carbon and hydrogen. Methane (CH4) is the simplest alkane. Alkanes form homologous series with the general formula CnH2n+2. They have single bonds between carbon atoms arranged in an open chain or branched chain. Methane is a colorless, odorless gas found in natural gas deposits. It burns with an invisible flame. Ethane (C2H6) is the second simplest alkane and is also a colorless, odorless gas obtained from petroleum. It is used to produce ethylene and other chemicals.
Development of Mesoporous Materials and Noble Metal Based Hydrodesulfurizatio...Lebong Andalaluna
The document discusses the development of mesoporous materials and noble metal-based hydrodesulfurization catalysts. It was found that Pt supported on acidic mesoporous materials like SiAlMCM-41 showed high catalytic activity for thiophene hydrodesulfurization that was higher than commercial CoMo/Al2O3 catalysts. Pt supported on moderately acidic SiAlMCM-41 (Si/Al=15) exhibited particularly high activity. The acidic properties of the MCM-41 support and the spillover hydrogen on Pt particles in Pt/MCM-41 catalysts were found to play an important role in thiophene hydrodesulfurization.
Alkanes are hydrocarbons composed of only carbon and hydrogen linked by single bonds. They belong to a homologous series with a general formula of CnH2n+2. Common alkanes include methane, ethane, propane, butane, pentane, and hexane. Alkanes have many uses including heating, electricity generation, cooking, polymers, gasoline components, paraffin wax, and as intermediates to make other chemicals. Their applications depend on the number of carbon atoms, with shorter alkanes like methane used for energy and longer ones components of fuels, lubricants, and polymers.
Maiyalagan,Electrochemical oxidation of methanol on pt v2 o5–c composite cata...kutty79
Platinum nanoparticles have been supported on V2O5–C composite through the reduction of chloroplatinic
acid with formaldehyde. The catalyst was characterized by X-ray diffraction and transmission electron
microscopy. Catalytic activity and stability for the oxidation of methanol were studied by using
cyclic voltammetry and chronoamperometry. Pt/V2O5–C composite anode catalyst on glassy carbon electrode
show higher electro-catalytic activity for the oxidation of methanol. High electro-catalytic activities
and good stabilities could be attributed to the synergistic effect between Pt and V2O5, avoiding the electrodes
being poisoned.
The document provides details about the music video being produced for the song "Keep On Walking" by the band Scouting For Girls. The 3-4 minute video will tell the story of the main singer waiting for his girlfriend to return home through a variety of shots filmed on location. It will include scenes of the singer at home and with band members, looking out the window for his girlfriend, and lip syncing the lyrics while walking in different outfits to show how the situation affects him.
Nonverbal communication plays an important role in effectively communicating messages. It can provide a crisper communication and show a person's intentions more clearly than verbal communication alone. There are several types of nonverbal communication, including kinesics (body movements and facial expressions), posture, gestures, haptics (touching), and movement/body position. Nonverbal communication serves functions like expressing emotions, attitudes, accompanying speech, self-presentation, and rituals like greetings. Both positive and negative aspects of nonverbal communication need to be considered, as it can help or hinder understanding depending on whether verbal and nonverbal signals are aligned.
The document lists 61 publications by Ramesh K. Sharma from 1980 to 2009. The publications are journal articles and conference papers related to catalysis, biomass conversion, and analytical pyrolysis. The list includes publications in journals like the Journal of Catalysis, AIChE Journal, Energy & Fuels, and Fuel Processing Technology as well as conference proceedings. Ramesh K. Sharma's research focused on the thermal and catalytic conversion of biomass and its application to fuels and energy. Many of the publications involved co-authors including N.N. Bakhshi and M.R. Hajaligol.
1) The characterization of lignin char and its reactivity towards the formation of polycyclic aromatic hydrocarbons (PAHs) were studied. Lignin char was prepared by pyrolyzing lignin at temperatures from 150 to 550 °C under both pyrolytic and oxidative atmospheres.
2) The chemical composition of char was characterized using techniques such as FTIR, CPMAS 13C NMR, and EDS. The surface area and morphology of char were also analyzed using BET and SEM.
3) The char yield from lignin pyrolysis decreased with increasing temperature until 400 °C, after which there was a gradual decrease to around 40% at 750 °C. In an oxidative atmosphere, the char
The document discusses aqueous phase reforming of sorbitol to produce value-added chemicals. It describes background studies on sorbitol and its potential for hydrogen production. The objectives are to identify value-added chemicals produced from reforming sorbitol over a Ni/Al2O3 catalyst promoted with Ca, and to synthesize and characterize the catalyst. The methodology involves preparing the catalyst using incipient wetness impregnation, characterizing it using TGA, SEM, and H2-TPR, and evaluating its performance in reforming sorbitol to identify products.
Effects of heat treatment on the catalytic activity and methanol tolerance of...sunidevi
This document summarizes a study on the effects of heat treatment on the catalytic activity and methanol tolerance of carbon-supported platinum alloys. Carbon-supported platinum (Pt/C) and platinum alloy (Pt-Co/C, Pt-Cu/C, Pt-Fe/C, Pt-Ni/C) catalysts were subjected to heat treatments at different temperatures. X-ray diffraction, transmission electron microscopy, and electrochemical measurements were used to characterize the catalysts and evaluate their oxygen reduction reaction activity and methanol tolerance. The results showed that heat treatment improved catalytic activity by increasing particle size but the optimal temperature depended on the catalyst. Pt-Cu/C treated at 350°C showed the highest activity and
This document summarizes research on hydrogen production from methanol decomposition over platinum and ceria-promoted platinum catalysts. Key findings include:
1) Increasing the platinum loading from 2% to 9% on alumina supports decreased the temperature for full methanol conversion from 405°C to 390°C.
2) Promoting platinum catalysts (5% and 9% loadings) with 10% ceria further decreased the full conversion temperature to 345°C and 315°C, respectively, with hydrogen selectivities over 99%.
3) The best performing catalyst was 9% Pt - 10% CeO2/Al2O3, achieving full conversion at 315°C with 99
Visible light driven photocatalytic oxidation of thiols to disulfides using i...Pawan Kumar
The present paper describes the synthesis of graphene oxide immobilized iron phthalocyanine (FePc) for
the photocatalytic oxidation of thiols to disulfides under alkaline free conditions. Iron phthalocyanine
tetrasulfonamide was immobilized on carboxylated graphene oxide supports via covalent attachment.
The loading of FePc on GO nanosheets was confirmed by FTIR, Raman, ICP-AES, UV-Vis and elemental
analyses. The synthesized catalyst was found to be highly efficient for the photo-oxidation of thiols to
disulfides in aqueous medium using molecular oxygen as oxidant under visible light irradiation. The
identification of photo-oxidation products and their quantitative determination was done using GC-MS.
After completion of the reaction, the catalyst was easily recovered by filtration and reused for several
runs without loss in activity and no leaching was observed during the reaction
Adam B. Powell developed a heterogeneous catalyst composed of palladium, bismuth nitrate, and tellurium metal that promotes the aerobic oxidative esterification of aliphatic alcohols with high yields. The addition of bismuth and tellurium additives significantly increased the rate of product formation and overall yield compared to the catalyst without additives. The catalyst was shown to esterify a variety of activated and aliphatic alcohols, expanding the scope of this transformation. Future work includes adapting the catalyst for other oxidative reactions and developing a robust Pd-Bi-Te catalyst for flow applications.
Effects of heat treatment on the catalytic activity and methanol tolerance of...tshankar20134
This document studies the effects of heat treatment on the catalytic activity and methanol tolerance of carbon-supported platinum alloys. Platinum (Pt), platinum-cobalt (Pt-Co), platinum-copper (Pt-Cu), platinum-iron (Pt-Fe), and platinum-nickel (Pt-Ni) catalysts were heat treated at different temperatures and their properties were analyzed. Heat treatment was found to increase particle size but also improved catalytic activity in most cases. The optimum heat treatment temperature depended on the specific catalyst. Pt-Cu/C and Pt-Fe/C catalysts heat treated at 350°C showed the highest oxygen reduction reaction activity and best methanol tolerance. Overall, Pt-
Disposition Pattern of Sulphur Functional Groups in High Sulphur Ledo Coals o...IOSR Journals
This document discusses a study of the distribution of sulfur functional groups in high-sulfur Ledo coals from Assam, India using Temperature Programmed Reduction (TPR). TPR studies were conducted on Ledo coal and model sulfur compounds between 190-6200°C in hydrogen gas. Six hydrogen sulfide evolutions were observed from Ledo coal, which were assigned to specific sulfur functional groups based on the TPR results from model compounds. These included mercaptan/disulfide, thiol, aromatic thioether, thiophene, pyrite, and complex thiophene groups. Additional experiments estimated the thioketonic sulfur content in Ledo coal to be 1.59%. Infrared spectroscopy was also used
1) The Pt supported on mesoporous silicate FSM-16 showed high and stable catalytic activity for the hydrodesulfurization of thiophene at 350°C and this activity was higher than that of commercial CoMo/A120 3 catalysts.
2) Among noble metal/FSM-16 catalysts, Pt/FSM-16 showed the highest activity for the hydrodesulfurization of thiophene. The optimal loading of Pt on FSM-16 was determined to be 5 wt%.
3) The activity of Pt/FSM-16 decreased temporarily when hydrogen sulfide was introduced but was restored after cutting off the introduction, indicating that hydrogen sulfide is reversibly adsorbed on the Pt/FSM
This document summarizes research on using various catalysts to promote the dehydrogenation of cyclohexane to produce hydrogen gas. Key findings include:
- Monometallic silver (Ag) catalysts supported on activated carbon cloth showed increasing hydrogen evolution rates with increasing Ag loading up to 10 wt%, but rates decreased at 15 wt% loading likely due to poorer dispersion.
- Bimetallic catalysts with 1 wt% noble metals (platinum, palladium, rhodium) promoted on 10 wt% Ag/ACC showed enhanced hydrogen evolution rates compared to the monometallic Ag catalyst. In particular, a 10 wt% Ag-1 wt% Pt catalyst produced hydrogen at twice the rate of the 10 wt%
Synthesis and Characterization of Atmospheric Residue Hydrodemetalization (Ar...IOSR Journals
This document describes the synthesis and characterization of an atmospheric residue hydrodemetalization (ARDHM) catalyst for crude oil processing using Indonesian natural zeolite. The zeolite was treated with HCl to increase acidity and then loaded with nickel and molybdenum metals via impregnation. Characterization showed the metals did not block pores or degrade crystallinity and increased acidity. Testing on model compounds like nickel porphyrin, thiophene and pyridine showed the catalyst effectively removed metals and sulfur at temperatures of 360-390°C. The spent catalyst was deactivated by coke deposition but could be regenerated through burning off the coke.
Nickel and cobalt transfigured natural clay: a green catalyst for low-tempera...Devika Laishram
Soot particulates in engine exhausts pose a severe threat to the environment and human health – causing cancer, affecting the heart and lungs and drives metal processes. This study proposes a practical,
real-world application of transition metal modified natural clay as an environmentally benign, low-cost,
green catalyst for soot oxidation. Ni and Co (NC-Clay) incorporated natural clay catalysts were prepared
by a simple wet impregnation method and meticulously characterized by different characterization
techniques. The catalyst exhibited higher H2 absorption at a lower temperature with similar trends as
observed in O2 TPD that indicated a remarkable redox property, which is useful for applications as a
catalyst in soot oxidation. Excellent catalytic activity with a very low T50 of 358 1C was observed and can
be accredited to the improved surface oxygen vacancies and thermal stability by the metal modification
of clay
Kinetics and feasibility studies of thiol oxidation using magnetically separa...Pawan Kumar
This work describes kinetic studies of the catalytic oxidation of thiols (RSHs) found in kerosene to disulphides using a magnetically separable iron oxide coated Mg-Al layered double hydroxide supported tetra-sulphonated cobalt phthalocyanine (CoPcS/LDH@Fe3O4) catalyst in an alkali-free environment. Using 1-octanethiol as a representative RSH, we investigated the effects of different experimental parameters on RSH oxidation kinetics, including catalyst concentration, temperature (30–60 °C), and initial thiol concentration ([RSH]0, 100–300 ppm). The catalyst concentration was varied so that the [RSH]0/[Co]tot molar ratio ranged from 45 to 180. Based on the results, we propose a mechanistic rate expression to explain the observed oxidation of RSH in the presence of the CoPcS/LDH@Fe3O4 catalyst. The proposed rate law resembles double substrate Michaelis-Menten kinetics, however, for commonly …
Kinetics and feasibility studies of thiol oxidation using magnetically separa...Pawan Kumar
This research article studies the kinetics of catalytic oxidation of thiols to disulfides using a novel magnetically separable catalyst. The catalyst contains cobalt phthalocyanine grafted onto an iron oxide-coated layered double hydroxide supported on magnetic iron oxide nanoparticles. Experiments were conducted to investigate the effects of various parameters on thiol oxidation kinetics, including catalyst concentration, temperature, and initial thiol concentration. Kinetic data was analyzed to propose a rate law that could be used to design industrial reactors for an alkali-free sweetening process.
Enhanced fluidized bed methanation over a Ni Al2O3 catalyst for production of...Pengcheng Li
This document summarizes a study that investigated the fluidization behavior and CO methanation performance of a Ni/Al2O3 catalyst in a fluidized bed reactor for producing synthetic natural gas. The researchers found that the pure Ni/Al2O3 catalyst failed to properly fluidize on its own due to particle sizes between 10 and 100 μm, but fluidization was improved by adding larger Al2O3 particles. Methanation performance in the fluidized bed reactor increased substantially with the Al2O3 addition. Temperature was found to control the methanation reaction mechanism, with surface reactions dominating at lower temperatures and external diffusion controlling at higher temperatures. Stability tests showed the fluidized bed reactor had higher CO conversion, methane selectivity
Effect of alumina support on the performance ofNan Wu
This document describes a study that investigated the effect of different alumina supports on the performance of Pt-Sn-K/γ-Al2O3 catalysts in isobutane dehydrogenation. Alumina supports were synthesized by hydrochloric acid reflux and ammonia precipitation methods. Pt-Sn-K/γ-Al2O3 catalysts were prepared using these different alumina supports. Testing found that the catalyst supported on alumina from ammonia precipitation had smaller Pt particle sizes, weaker acidity, higher activity, and better selectivity and stability for isobutene production compared to the catalyst supported on alumina from hydrochloric acid reflux.
1991_Sensitivity to Iron Impurity Content of Corrosion Rate of Mg-15Al_Cotton...James D. Cotton
The corrosion rates of extrusions produced from rapidly-solidified Mg-15wt%AI alloy powder containing varying levels of iron (Fe) impurity (0.003-0.020wt%) were studied. Trace amounts of Fe were found to have a strong exponential effect on the corrosion rate, consistent with previous studies. However, the sensitivity to Fe content was markedly lower for the rapidly-solidified alloys compared to conventionally-cast alloys. This effect is explained by the microstructural refinement produced by rapid solidification, which decreases the scale of microstructure and distributes corrosion more evenly. Both pitting and filiform corrosion were observed and characterized using various microscopy techniques.
The document summarizes research on the phase transformation of sol-gel titania containing silica. Key findings include:
1) The addition of 5-10% silica to titania increases the specific surface area of the material from 89 m2/g to over 200 m2/g. Using ethanol as the solvent medium achieved the highest surface area of 232 m2/g.
2) The addition of silica increases the anatase-rutile phase transformation temperature of titania from around 800°C to higher temperatures.
3) The phase transformation was studied using X-ray diffraction and impedance spectroscopy. The addition of methanol or ethanol was found to enhance the formation of the rutile
This document summarizes research on developing Pt/V2O5-C composite catalysts for methanol oxidation in direct methanol fuel cells (DMFCs). Pt nanoparticles were dispersed on a V2O5-C composite support through chemical reduction. The catalyst was characterized using XRD and TEM, which showed the formation of small Pt nanoparticles (~3 nm) on the support. Electrochemical testing showed that the Pt/V2O5-C composite catalyst had higher catalytic activity for methanol oxidation compared to a commercial Pt/C catalyst, as indicated by a more positive onset potential and higher forward/reverse peak current ratios. The composite catalyst also demonstrated comparable stability during chronoamperometry testing. The improved performance is attributed to
2. Direct liquefaction of coal." D. Tian et al.
resulted in a significant increase in activity. In these ash (db). The elemental composition (wt%) is: C, 81.9;
studies too, the catalysts were mixed with, rather than H, 6.3; N, 1.5; S, 0.9.
impregnated into, the coal.
The conversion of coal is also governed by the type of Catalyst
solvent used in liquefaction. According to McMillen Catalysts with varying amounts of second metal were
et al.ll, the role of the solvent is to stabilize the coal free- prepared. They are designated as A1-A3 (with magne-
radicals by donating hydrogen as well as to promote the sium) and B1 (with molybdenum).
cracking of coal molecules. The use of tetralin as solvent Catalysts of type A1 were not impregnated in situ.
is widely reported in the literature, owing to the strong Instead, they were prepared by mixing stoichiometric
hydrogen donor properties of tetralin. However, Stohl amounts of ferric chloride, sodium sulfide and mag-
and Diegert4 observed that catalytic effects in the nesium acetate, all in aqueous solutions. In order to
presence of tetralin are small, since tetralin itself can obtain small particles, weak solutions (0.01 M) of the
supply almost all the hydrogen necessary for the starting reagents were used. The precipitate was filtered,
liquefaction of coal. Phenanthrene is known to be a washed and dried under vacuum at 85°C. This catalyst
poor hydrogen donor solvent compared with tetralin ~2. was mixed with coal at a loading of 8.4 wt% (based on
Hence DCL conversions should be smaller in the daf coal). The Mg fractions (fMg, Mg/(Mg + Fe) ratio)
presence of phenanthrene than with tetralin, and were 0.01, 0.05, 0.1 and 0.5.
catalytic effects should be more pronounced in the Catalysts A2 and A3 were impregnated in situ on the
presence of phenanthrene than with tetralin. However, coal. To do this, coal was first added to the dilute
phenanthrene may enhance cracking reactions during aqueous ferric chloride solution. The slurry was mixed
DCL. thoroughly before adding the dilute sodium sulfide and
Anderson and Bockrath 13 observed that the activity of magnesium acetate solutions. The mixture was agitated
iron-based catalysts was improved by the addition of for 2h and filtered. The impregnated coal was dried
sulfur, especially when the S/Fe molar ratio of the overnight in N2 at 85°C under vacuum. The catalysts
catalyst was <1. The effect of sulfur was attributed loadings were 1.67wt% (A2) and 8.5wt% (A3), again
mainly to the formation of catalytically active pyrrhotite. based on daf coal. The values offMg were again 0.01,
The objective of the present study was to investigate 0.05, 0.1 and 0.5.
the performance of impregnated, iron-based, mixed- The molybdenum-containing catalysts were prepared
metal catalysts in DCL using various solvents. The basic in the same way as the F e - M g - S catalysts, except that
catalyst is an intimate mixture of pyrite and pyrrhotite ammonium heptamolybdate solution was used in place
obtained by disproportionation of ferric sulfide. The of magnesium acetate solution. The catalyst loading was
in situ impregnation technique used earlier for the iron- 1.67 wt%. The fMo ratios (Mo/(Fe + Mo)) were 0.05,
alone catalyst was modified to generate mixed-metal 0.08, 0.1, 0.15 and 0.25. A few runs were also made with
sulfides. The second metal was generally incorporated catalysts in which the ammonium heptamolybdate
before disproportionation and impregnation. The solution was added to Fe-impregnated coal after the
second metals used in this work were magnesium and filtration. In some cases, a small amount (5wt%) of
molybdenum, both of which meet the Hume-Rothery ferrous chloride was added to the ferric chloride solution,
criteria. Magnesium was selected to determine whether a to check if the extent of precipitation of MoS2 is altered
metal with a significantly lower cost and less strategic by the addition of ferrous chloride.
importance than Ni or Mo could be used in conjunction
with iron to obtain comparable results. Molybdenum Liquefaction equipment and proeedure
was selected because of the performance of the non- A stainless steel tubing bomb reactor with a volume of
impregnated non-sulfide Fe-Mo catalysts described 27ml was used for the liquefaction. The reactor was
above. Different concentrations of these second metals charged with 3 g of impregnated coal, 4.7 g of tetralin or
were used, but the concentration of the second metal was phenanthrene, and 0-0.I ml CS2. After loading, the
kept low in all cases, so that these catalysts would be reactor was purged and pressurized with hydrogen to
economically and environmentally desirable. Tetralin 6.9MPa (cold). The reactor was heated in a fluidized
and phenanthrene were used as solvents to investigate sand bath which was preheated to the desired tempera-
the effects of facile hydrogen donation from the solvent. ture before the run. At the end of the run, the reactor was
Runs were made at 350-440°C with a hydrogen pressure quenched in water. The run duration was 30 min or 1 h.
of 6.9 MPa (cold). The products were analysed in terms In some runs, the gaseous products were collected in a
of the asphaltene fraction and the oil-plus-gas fraction. sampling flask and analysed by gas chromatography.
In all cases, the results were compared with those from The amount of gas was evaluated on a hydrogen-free,
iron-alone catalysts prepared similarly. ethane-equivalent basis, i.e. the response factors for
various components of the gaseous product (other than
EXPERIMENTAL hydrogen) were assumed to be the same as that for
ethane. Additional details on equipment and procedure
Coal are available elsewhere 2.
The coal used in this study was DECS-6, which is a The solid and liquid products in the reactor were
high-volatile-A bituminous coal from the Blind Canyon washed and extracted with tetrahydrofuran (THF) for
seam in Utah. The coal was received from the 24 h. The THF-insoluble material (TI) was separated by
Pennsylvania State University Coal Bank and ground filtration. The overall conversion of the original material
to <250 #m under nitrogen. DECS-6 was used in this was calculated from the amount of TI. After the removal
work because of its extremely low pyrite content, thus of THF by rotary evaporation, the THF-solubles were
allowing the effect of added iron catalyst to be obtained. extracted with hexane for 2 h. The extract was separated
The coal is of 49wt% volatile matter (daf) and 6.3 wt% into hexane-insoluble (HI) and hexane-soluble (HS)
752 Fuel 1996 Volume 75 Number 6
3. D#ect fiquefaction of coaL D. Tian et al.
fractions by filtration. The THF-soluble-hexane- RESULTS AND DISCUSSION
insoluble fraction, i.e. the HI fraction, was defined as
asphaltenes. The conversion (X) and the yield of Effect o f solvent
asphaltenes (A) were calculated on dry, ash-free (daf) Figure 1 compares the results for the two solvents
basis as follows: tetralin and phenanthrene. With tetralin, and in the
absence of any catalyst, 57 wt% of the coal is converted.
X = (F m - TI)/Fda f (1) On the other hand, with phenanthrene as solvent, the
uncatalysed conversion is much lower. These results are
A = HI/Fda f (2) consistent with those reported earlier4.
where Fm and Fda f represent the amount of feed on the The yield of oil-plus-gas is ~7 wt% in each case. This
moisture-free and daf bases, respectively. (The form of shows that the yield of asphaltenes is higher with tetralin
Equation (1) is used so that the ash content does not have than with phenanthrene. Clearly the solvent has a
to be subtracted separately from TI.) When the gas yield, considerable effect on the conversion and product slate
G, was determined (independently) from the gas analysis, for the uncatalysed reaction. Because of the lower values
the oil yield, O, was obtained by difference: of conversion and yield obtained in non-catalytic runs
with phenanthrene, experiments using this solvent can
O = X- A - G (3a) more easily differentiate between the activities of various
In runs where the gaseous product was not analysed, the catalysts than can experiments with tetralin.
combined oil-plus-gas yield (OG) was obtained by Catalytic results are also shown in Figure 1. For
difference: simplicity, a second metal is not considered. With either
solvent, the conversion increases when iron-alone
OG = X - A (3b) catalysts of loading 1.67wt% (type A2) are used. The
increase due to the catalytic activity is about 6 percentage
Most of the runs were made in duplicate and the points in the case of tetralin and 23 percentage points in
reproducibility was better than +3%. the case of phenanthrene. The yield of asphaltenes also
increases correspondingly in each case. Catalyst A3, with
Catalyst characterization
the higher loading (8.4wt%), has even more dramatic
Coal mixtures containing iron-molybdenum catalysts effect on the results: the conversions are 8 percentage
were characterized in terms of pyrrhotite/pyrite ratio, points higher than those with A2, and the oil-plus-gas
PH/PY, before and after reaction. The amounts of PH yields are about 5 percentage points higher.
and PY were measured in terms of hydrochloric acid Significantly, the conversions and yields with the two
solubility and nitric acid solubility, respectively, in that solvents in the catalytic runs are almost indistinguish-
order. The solutions from the acid dissolution were able. In other words, this catalyst may make it
analysed by atomic absorption spectroscopy (AAS) to economically advantageous to use a cheaper poor-
obtain the amount of iron. The contributions of PH and hydrogen-donor solvent. Similar observations were
PY from the raw coal alone were also obtained. These made when the second metal was added to the catalyst.
could be subtracted from the values for the catalyst plus It is well known that the initial step in coal liquefaction
coal mixtures, at least for the pre-liquefaction samples. is the thermal fragmentation of the coal molecules to
X-ray diffraction (XRD) and Auger electron spectro- produce free radical species u. These free radicals must
scopy (AES) of some samples were also carried out. be stabilized by hydrogen in order to prevent their
100
Conversion, Oil+Gas Yield
80 D
I I, ~ Thermal
v
1~7"~, ~ Catalyst A2
.o 60 ~, ~ Catalyst A3
+
40
O
2C
..r,
0~
O
Tetralin Phenanthrene
Figure 1 Effect of solvent type on conversion and yield for catalysts A2 and A3 withfMg = 0. Reaction conditions: 350°C, 1 h, 4.7 g solvent, 0.1 ml
CS2
Fuel 1996 Volume 75 Number 6 753
4. Direct fiquefaction of coaL" D. Tian et al.
recombination by the retrogressive reactions. The are probably due to better dispersion of the small catalyst
necessary hydrogen may come from the solvent, the particles on the coal than in the physical mixtures of
gaseous hydrogen or the coal itself. Tetralin is a good catalyst and coal. However, the yields of the oil-plus-gas
hydrogen donor and can supply almost all the hydrogen fraction are somewhat lower with the impregnated
necessary for the stabilization of the radicals, resulting in catalysts than those with A1. The improved conversion
the higher coal conversions seen in Figure 1. The catalyst and lower oil-plus-gas yields for the impregnated
in this case may have a role only in the hydrogenation of catalysts result in higher asphaltene yields for this
the spent solvent by the gaseous hydrogen. mode of preparation.
Phenanthrene on the other hand is a poor hydrogen In any case, the catalyst performance is not very
donor solvent and consequently the conversion of coal is largely altered by the addition of magnesium, as
lower than that with tetralin. However, it has been indicated by Figures 2 and 3.
reported that phenanthrene is a good hydrogen acceptor In order to determine if the catalytic activities are
and allows the transfer of hydrogen from the gas phase dependent on the amount of sulfur, runs were made at
to the coal radicals in the presence of iron sulfide various CS2 levels using catalyst A3 withfM~ = 0.01. The
catalyst 14. The increase in coal conversion in the catalytic conversion and oil-plus-gas yield increase with increasing
runs is probably due to the faster hydrogen transfer CS2, but by a maximum of 1 percentage point, again
processes from the gas phase. less than the expected error bars. This indicates that
presulfiding does not improve the activity and selectivity
Mixed-metal catalysts containing magnesium of these catalysts significantly, as observed previously3.
Figure 2 shows the effect of magnesium fractionfMg on The negligible effect of CS: addition is consistent with
conversion and product yield using the physically mixed observations of Anderson and Bockrath ~3, since the S/Fe
F e - M g - S catalysts, type A1. At 350°C when fMg = 0, molar ratio for these catalysts is higher than unity
64wt% of coal is converted, and the oil-plus-gas yield (nominally 1.5, based on Fe2S3).
(OG) is 15 wt%. The high conversions may be due to the
presence of tetralin as the solvent. The addition of Mixed-metal catalysts containing molybdenum
magnesium (fMg =0.01) can be seen to affect the These catalysts were tested at 350-440°C using
catalytic activity positively, but the improvement (one phenanthrene as solvent. In preliminary runs, no
percentage point) is well within the limits of error noted significant advantage in activity was gained when
earlier. At higherfMg values, conversions are lower than catalyst loading was increased above 1.67wt%. Hence
for the iron-alone catalyst 0cMg= 0), and oil-plus-gas the loading was kept constant at 1.67 wt% in all the runs.
yields are little changed. These decreases are greater than At 350°C, the conversion of coal is 2-3 percentage points
the error bars noted earlier. higher using the F e - M o - S catalyst withfMo = 0.05 than
Figure 3 compares the activities of physically mixed with the iron-alone catalyst. Similarly, the conversion
catalyst (A1) and impregnated catalyst (A3), both at to asphaltenes is 6-7 percentage points higher with the
8.4 wt% catalyst loading. The activities of catalysts A3 at F e - M o - S catalyst. These are significant differences.
all the fMg ratios are 5-10 wt % higher than those of A 1. The results at 400°C, presented in Figure 4, are even
These numbers are greater than the error bars, and more interesting. The conversion and yields with the F e -
indicate that the impregnated catalysts are superior to M o - S catalysts are considerably higher than those with
the physical mixtures of catalyst and coal. This result is iron-alone catalyst. A maximum conversion of 88 wt% is
consistent with the observations of Weller l, among achieved when fMo = 0.15. The oil-plus-gas yield is a
others. The higher activities of the impregnated catalysts maximum (25 wt%) when fMo is 0.1 or 0.15. The reason
70--
60
"---o
.o
50
0
~
e~
20
0
v
0
0
~ 10 n
o Conversion
• Oil+Gas Yield
I I // I I
0.00 0.05 0.10 0.5
Mg/(Fe + Mg)
Figure 2 Effect of Mg/(Fe + Mg) ratio on conversion and oil-plus-gas yield for catalyst A1. Reaction conditions as in Figure 1, except that the solvent
is tetralin
754 Fuel 1996 Volume 75 Number 6
5. Direct fiquefaction of coal." D. T/an et al.
100
AI A3
[ I,~'/A Conversion
Oil+Gas Yield
"O
m
>.
~3
.4-
50 -- //
*O
.o
o
=!
0.00 0.01 0.05
Mg/(Fe + Mg)
Figure 3 Comparison of the performance of physically mixed catalyst (A1) and impregnated catalyst (A3). Reaction conditions as in Figure I except
that the solvent is tetralin
for a decrease in conversion at fMo = 0.25 is not clear. to an improvement in the catalyst activity. However, the
One possibility for the lower activity atfMo = 0.25 may conversions of coal in these runs are not very different
be the lower iron content of the catalyst. It is also from those with catalysts prepared without the ferrous
possible that there is a maximum in the dispersion of Mo chloride addition. Further, the yield of gas appears to
on the catalyst surface corresponding to fMo = 0.1-0.15. increase slightly, whereas the oil yield decreases. This
Gardner et al. 15 observed a similar optimum in the Mo indicates that any early precipitation of the Mo sulfide
concentration in their studies on pyrene hydrogenation (in the absence of ferrous chloride) has at best little effect
over NiMo catalysts. on catalyst performance.
These results show that the addition of molybdenum is In some instances the Mo source (ammonium hepta-
beneficial to the activity and selectivity of the catalyst. molybdate) was added to the Fe-impregnated coal
Runs were also made with catalysts prepared using a after filtration. The corresponding results are shown in
mixture of ferrous and ferric chlorides instead of ferric Figure 5. The conversions and yields appear to be
chloride alone. It was thought that the extent of MoS2 independent of the stage at which the molybdenum
precipitation might be controlled by ferrous ions, leading solution is added to the coal. This would imply that the
I
80
¢>
Thermal
60--
O
+
/
30'--
,,~
0
0
20 - Thermal
0 I I
0.0 0.1 0.2
Mo/(Fe + Mo)
Figure 4 Effect of Mo/(Fe + Mo) ratio on conversion and yield for catalyst B1. Reaction conditions: 400°C, 0.5 h, 4.7 g phenanthrene, 0.1 ml CS2.
Fuel 1996 Volume 75 Number 6 755
6. Direct fiquefaction of coaL" D. Tian et al.
Mo added before filtration, air-exposed
loo - I I Mo after filtration, air-exposed
Mo before filtration, not exposed to air
'~ 90 --
~ 80
0
i
1I
~ 20
0
rj
1o
i
0.0 0.05 0.10 0.15
Mo/(Fe + Mo)
l~gm'e 5 Effects of order of Mo addition and of air exposure for F e - S and F e - M o - S catalyst on performance. Reaction conditions as in Figure 4
amount of molybdenum that is not on the coal but However, the oil-plus-gas yields in the catalytic runs at
remains in solution (and therefore is lost during 400 and 440°C are also higher than in the non-catalytic
filtration) is negligible. runs. Further, the gas yields in the F e - M o - S runs are
In order to study the effect of exposure to air on the much smaller than those in the non-catalytic runs and the
performance of the various F e - M o - S catalysts, runs iron-alone runs. Hence the molybdenum addition can be
were made in which the catalyst was not exposed to air at seen to improve the oil yield significantly at 400 and
any time during or after impregnation on coal. The 440°C.
results from these runs are also presented in Figure 5. As An exact comparison of the present results with those
seen in the figure, for iron-alone catalysts, the conversion in literature is difficult, due to the differences in the type
increases by 3 percentage points when the catalyst is not of coal used as well as in the liquefaction conditions such
exposed to air. Also, the oil-plus-gas yield increases by as reaction time and type of solvent. Cugini et al. 6
about 4 percentage points. These increases are consistent studied the liquefaction of Blind Canyon bituminous
and significant. Similar observations can be made for the coal (DECS-6) at 425°C and 6.9 MPa H2 pressure for
F e - M o - S catalysts, for which the increase in conversion 30min reaction time, using Panasol (a mixture of
is greatest atfMo = 0.1. However, the increase in oil-plus- alkylated naphthalenes) as solvent. The conversion of
gas yield appears smaller in this case than for the iron- coal in the absence of catalyst was ,,,58 wt%, with an oil
alone catalyst. yield of 30 wt%. Using impregnated FeOOH as catalyst,
The decrease in the activity of the catalysts on the conversion and yield increased to 85 and 41 wt%
exposure to air may be due to structural changes and respectively. With molybdenum catalyst, the conversion
oxidation of the small particles of the catalyst, and the increased further to 90 wt%, with a small increase in oil
changes in the surface structure that follow. However, it yield. These values are similar to those in the present
has not been possible to demonstrate this unequivocally study (Figure 6). Hager et al. 9 used iron-based mixed-
for the impregnated samples, because of the difficulty in metal catalysts to study the liquefaction of a Wyodak
locating the catalytic material in the coal matrix. Some Black Thunder subbituminous coal at 415°C with
characterization results are given in the following tetralin as solvent. The activity of a catalyst containing
subsection. Mo was 6 percentage points higher than for the iron-
The effect of temperature on catalyst activity is alone catalyst. Zhao et al. 5 used a ferrihydrite catalyst to
presented in Figure 6. Results of thermal (non-catalytic) study the liquefaction of a Blind Canyon bituminous
runs are also shown for comparison. The catalysts were coal (DECS-17) at 400°C with tetralin as solvent. It was
not exposed to air and the fMo values were 0, 0.1 and observed that the conversion increased from 81 wt%
0.15. The results from runs at fMo = 0.15 are not (without catalyst) to 85 wt%. The increase in oil yield
included in the figure, since they were similar to those was <2 wt%.
atfMo = 0.1. At 350°C, the addition of a small amount of Even though the above results cannot be compared
molybdenum serves to double the difference between the directly with those from the present study, the activities
catalytic and non-catalytic conversions. When the of the present mixed-metal catalysts are as high or as
temperature is 400 or 440°C, the conversions with iron- better than those of the catalysts used. In particular,
alone catalyst far surpass the non-catalytic conversions. for the studies where tetralin was used as solvent, the
Using F e - M o - S catalysts, the conversions increase still results are comparable with the present results using
further. The increase due to Mo addition at the higher phenanthrene.
temperatures are less significant than at the lowest
temperature, perhaps because the conversion with the Catalyst characterization
iron-alone catalyst is so close to 100 wt% to begin with. The amounts of iron in the impregnated coal and the
756 Fuel 1996 Volume 75 Number 6
7. Direct fiquefaction of coal. D. Tian et al.
Thermal fMo=O fMo=O.1
V-1. I~ Conv.
lO0 Oil+Gas
_ _ , Gas
~ 80
+
~) 60
"~ 40
ill-
20
0
350 400 440
Temperature (°C)
Figure 6 Effect o f temperature on performance of F e - S and Fe M o - S catalysts. Reaction conditions as in Figure 4 except that the temperature is as
indicated and the catalysts were not exposed to air
liquefaction residue, and the corresponding PH/PY exposure of the catalyst to high temperatures and
ratios, are presented in Table 1. The figures indicate hydrogen pressures during liquefaction. This is consist-
that a very large fraction of the iron used is actually ent with earlier observations 2 with iron-alone catalyst.
impregnated on the coal, but a not negligible fraction is An attempt was made to characterize the F e - M o - S
lost during DCL. catalysts by X-ray diffraction (XRD) and Auger electron
From the first column, the total amount of iron spectroscopy (AES). However, due to the presence of the
detected in the impregnated coal is 8 - 9 m g g -1. This coal, the crystallinity of the samples was too low for the
amount is only 6-9% less than the amount of iron used XRD pattern to be meaningful. Charging of the
in the catalyst preparation. The difference is the amount impregnated coal was also a major difficulty for AES,
of iron lost in the filtrate from catalyst preparation. In hence many samples could not be analysed. To remedy
the second column, the amount of iron in the sample this, an F e - M o - S catalyst with fMo = 0.1 was impreg-
after reaction is obtained per gram of residue. Hence this nated on comparable graphite particles. Spectra of
figure is much higher than that in the previous column. catalyst-coal particles, where obtained, were compar-
Multiplying this value by (1 - X) leads to a calculated able with those of the corresponding catalyst-graphite
amount of iron per weight of coal after reaction, shown samples. Finally, some F e - M o - S catalysts were pre-
in the third column. This figure can be compared with the cipitated during preparation in the absence of coal or
value before reaction. The comparison shows that the graphite.
decrease is ,,~25% atfM o = 0.05, 44% atfM o = 0.1 and The AES results are summarized in Table 2. Here
34% atfMo = 0.15. This indicates that some iron is lost 'precipitated' refers to the catalyst in the absence
to the liquefaction products. of graphite (or coal), 'catalyst-graphite' refers to the
PH/PY ratios are also shown in Table 1. These figures as-impregnated graphite, while 'THF-insoluble' refers to
indicate that the pre-liquefaction values of the ratios the liquefaction residue. In some cases, the carbonaceous
for catalysts increase with increase in Mo content, from material from the liquefaction residue was removed by
7.4 for iron-alone catalyst (fMo = 0) to ~15 when dissolution in N-methylpyrrolidone (NMP); the resulting
fMo = 0.1-0.15. Interestingly, the high PH/PY ratios at material, presumably the catalyst and other inorganic
fMo = 0.1-0.15 correspond to catalysts which have matter, was analysed by AES. Accordingly, in Table 2,
higher activities than those with lower fMo ratios. The 'NMP-insoluble' refer to the residue after washing with
PH/PY ratios in the residues obtained after liquefaction NMP.
are much lower than in the impregnated coal before The results are shown as fractions of S and Mo relative
liquefaction. The decrease is probably due to the to Fe plus Mo on the surface. They indicate that the
Table 1 Total iron and PH/PY ratio of F e - M o - S catalyst
Total Fe PH/PY ratio
Before DCL After DCL After DCL Before After
fMo (mgg -1 coal) (mgg i residue) (mgg -1 coal) DCL DCL
0.0 8.58 n.d. a n.d. 7.47 n.d.
0.05 7.74 46.07 5.82 9,76 1.22
0.1 8.6 39.82 4.78 15.39 1.05
0.15 8.18 42.12 5.36 14.18 1.05
Not determined
Fuel 1996 Volume 75 Number 6 757
8. Direct liquefaction of coal." D. Tian et al.
Table 2 Surfaceanalysis of Fe-Mo-S catalysts (fMo= 0.1) to the oil yield. Activity and selectivity to the oil
Surface ratio fraction increase with temperature, at least up to
440°C.
Catalyst type S/(Fe + Mo) Mo/(Fe + Mo) 5. With the precipitated F e - M o - S catalysts, the surface
Precipitated 1.2 0.17 is Mo-rich and S-poor. On impregnation, the S and
Catalyst-graphite 1.1 0.0 M o contents of the catalyst surface decrease appre-
THF-insoluble 0.5 1.0 ciably. After DCL, carbonaceous material covers all
NMP-insoluble 1.8 0.17 the Fe sites on the surface and a large fraction of the S
sites on the surface.
surface of precipitated catalyst is slightly S-poor, relative 6. Catalytic effects during D C L are more evident when
to the bulk value of S / ( F e + Mo) = 1.4 (assuming Fe2S3 phenanthrene is used as solvent, relative to tetralin.
with fMo = 0.1). On the other hand, the surface of the 7. Isolation of F e - M o - S catalysts from air improves
fresh catalyst is enriched with Mo, relative to the their performance.
expected value of 0.1. Both these effects are counter to
those observed previously with Ni catalyst 8. Hence it
is not surprising that the catalytic performances of the ACKNOWLEDGEMENTS
F e - N i - S and F e - M o - S materials are different. This work was conducted under US Department of
The presence of graphite decreases slightly the fraction Energy Contract No. DE-FC22-90PC90029 under the
S/(Fe + Mo) on the surface, relative to the precipitated Cooperative Agreement with the Consortium for Fossil
sample. However, the surface Mo ratio is considerably Fuel Liquefaction Science. The authors are grateful to
diminished when the catalyst is impregnated on the A. Chadha for the AES analysis and to J. Yang for
graphite, again compared with the precipitated sample. performing the AAS.
(The value of zero for this entry in Table 2 indicates that
the signal for Mo was below the detection limit.
Typically, AES can detect species comprising 0.1% of REFERENCES
the atoms on the surface. Recall that the bulk Mo
loading is 0.1 of 1.67 wt%. Hence a small but detectable 1 Weller, W. Energy Fuels 1994,8, 415.
S.
signal would be expected if the Mo was present to the 2 Dadyburjor, B., Stewart, W. E., Stiller, A. H., Stinespring,
D.
C. D., Wann, J. P. and Zondlo, J. W. Energy Fuels 1994,8, 19
same extent on the surface as it was in the bulk.). 3 Stansberry, G., Wann, J. P., Stewart, W. R., Yang, J., Zon-
P.
In the THF-insoluble fraction, the Fe signal is dlo, J. W., Stiller, A. H. and Dadyburjor, D. B. Fuel 1993,72,
negligible, but it reappears after the N M P wash. This 793
indicates the presence of significant carbonaceous 4 Stohl, F.V. andDiegert, K . V . EnergyFuels1994,8,117
material ('coke') on Fe during DCL, but not on Mo. 5 Zhao,J., Feng, Z., Huggins, F. E. and Huffman, G. P. Energy
Fuels 1994,8, 38
The S signal is reduced after liquefaction, but to a lesser 6 Cugini,A. V., Krastman, D., Lett, R. G. and Balsone, V. D.
extent than the Fe signal, and the S signal also reappears Catalysis Today 1994, 19, 395
after the N M P wash. 7 Liu, Z., Yang, J., Zondlo, J. W., Stiller,A. H. and Dadyburjor,
D. B. Fuel 1996, 75, 51
8 Dadyburjor,D. B., Stiller, A. H., Stinespring, C. D., Zondlo,
CONCLUSIONS J. W., Wann, J. P., Sharma, R. K., Tian, D., Agarwal, S. and
Chadha, A. Am. Chem. Soc. Div. Fuel Chem. Preprints 1994,
1. Mixed-metal sulfide catalysts can be made with the 39, 1088
primary metal iron based on the disproportionation 9 Hager,G. T., Compton, A. L., Givens, E. N. and Derbyshire,
of ferric sulfide. F. J. Am. Chem. Soc. Div. Fuel Chem. Preprints 1994,39, 1083
10 Pradhan,V. R., Herrick, D. E., Tierney,J. W. and Wender, I.
2. The catalysts can be precipitated separately and later Energy Fuels 1991,5, 712
physically mixed with the coal, or the catalysts can be 11 McMillen, F., Malhotra, R. and Tse, D. S. Am. Chem. Soc.
D.
impregnated in situ on the coal. DCL activities of the Div. Fuel Chem. Preprints 1991,36, 498
latter catalysts are higher, while oil yields are smaller. 12 Whitehurst,D. D., Mitchell, T. D. and Farcasiu, M. 'Coal
Liquefaction', AcademicPress, New York, 1980
3. Mixed-metal catalysts containing magnesium provide 13 Anderson,R. R. and Bockrath, C. B. Fuel 1984,63, 329
no particular advantage over the iron-alone catalyst. 14 Wilson,M. A., Rottendorf, H., Collins, P. J., Vassallo, M. A.
4. The presence of 0.1-0.15 atom fraction of Mo in iron- and Barron, P. F. Fuel 1982,61,357
based catalysts results in an active catalyst for DCL. 15 Gardner,T. J., McLaughlin,L. I., Lott, S. E. and Oelfke,J. B.
Am. Chem. Soc. Div. Fuel Chem. Preprints 1994,39, 1078
The addition of molybdenum is especially beneficial
758 Fuel 1996 Volume 75 Number 6