This document summarizes research evaluating the effectiveness of various desiccants for drying several dipolar aprotic solvents, including hexamethylphosphoric triamide (HMPT), dimethylformamide (DMF), dimethyl sulfoxide (Me2SO), and acetone. The study found that while calcium hydride and molecular sieves were moderately effective for some solvents, the best desiccant varied between solvents. For example, boric anhydride most effectively dried acetone to a water content of only 18 ppm, while sequential drying with molecular sieves was most successful for DMF, achieving a content below 100 ppm. The results emphasize that the best desiccant depends on solvent properties and
Biohydrogenation of unsaturated fatty acidsMevlut Gunal
The biohydrogenation of unsaturated fatty acids like linoleic acid and punicic acid by Butyrivibrio fibrisolvens results in the formation of trans-11-octadecenoic acid. Experiments with deuterium (heavy water) showed that deuterium was incorporated into the cis double bonds that were reduced, indicating stereospecific reduction. This reduction occurs via cis addition to the lower (D) side of intermediates like cis-9,trans-11-octadecadienoic acid. The distribution of deuterium at the reduced carbon atoms suggests that reduction occurs via addition of a proton and hydride ion mediated by an unknown carrier.
Common laboratory preparation and binary mixture (2)Vivek Singh
This document discusses common solvents, laboratory reagents, drug synthesis, and separation of binary mixtures. It provides examples of common solvents like water, acetic acid, acetone, and benzene. Examples of common analytical reagents include Fehling's reagent, Millon's reagent, iodine reagent, and Schiff's reagent. Methods for synthesizing drugs like sodium benzene sulphonate and dibenzal acetone are described. Techniques for separating binary mixtures using differences in physical properties, chemical properties, or volatilities in aqueous solution are also summarized.
This document summarizes Dr. V. A. Chatpalliwar's lecture on separation techniques. It discusses various chromatographic and physical separation methods that can be used to separate binary mixtures and chiral compounds. These include TLC, HPLC, GC, and techniques based on differences in solubility such as extraction with acidic or basic solutions. The document provides guidance on properly selecting and applying separation methods, including considering the properties of the compounds involved and avoiding approaches that could damage or contaminate the samples.
TLC Separation of Cephalosporins on Stannic Arsenate LayersIOSR Journals
Abstract: The chromatographic behaviour of some cephalosporins has been studied on synthetic stannic arsenate layers using citrate and borate buffers as mobile phases. Several ternary and quaternary separations have been achieved. The utility of these separations has been demonstrated for estimation of cephalosporins in blood serum from patients.This method used is simple, rapid ,reproducible and can also be applied in the separation and determination of cephalosporins in other biological samples. The limit of detection was found to be 0.20 μg/l.
This document provides information about qualitative organic analysis procedures at Tumkur University in India. It discusses preliminary tests, determination of physical properties, elemental detection using sodium fusion, solubility testing, and characteristic reactions to identify functional groups of compounds. The document is from the university's Department of Studies and Research in Organic Chemistry and is part of their practical manual for organic chemistry students, covering topics like separation of mixtures, systematic analysis steps, and specific reactions to identify compounds like alcohols and amides.
Oxidative treatment of high explosives contaminated wastewaterRaafat Alnaizy, PhD
1) The document discusses methods for treating wastewater contaminated with high explosives (HE) such as TNT, RDX, and HMX through catalytic/non-catalytic wet oxidation and advanced oxidation processes using ultraviolet light and hydrogen peroxide.
2) Catalytic and non-catalytic wet oxidation experiments were conducted in a batch reactor at moderate pressures and temperatures using a Pt/TiO2 catalyst.
3) Ultraviolet photolysis experiments alone and in combination with hydrogen peroxide were carried out in a glass photoreactor at ambient conditions using a low-pressure mercury lamp.
Solution- and solid-phase synthesis of 4-hydroxy-4,5-dihydroisoxazole derivat...Peter ten Holte
This document describes research into the solution-phase and solid-phase synthesis of 4-hydroxy-4,5-dihydroisoxazole derivatives from enantiomerically pure N-tosyl-2,3-aziridine alcohols. In the solution-phase process, N-tosyl-2,3-aziridine alcohols are directly converted to the corresponding 4-hydroxy-4,5-dihydroisoxazole 2-oxides in one pot through oxidation to the aldehyde followed by tandem nitroaldol-intramolecular cyclization. This provides a direct route to enantiopure 4,5-dihydroisoxazoles in good yields. A solid-
Biohydrogenation of unsaturated fatty acidsMevlut Gunal
The biohydrogenation of unsaturated fatty acids like linoleic acid and punicic acid by Butyrivibrio fibrisolvens results in the formation of trans-11-octadecenoic acid. Experiments with deuterium (heavy water) showed that deuterium was incorporated into the cis double bonds that were reduced, indicating stereospecific reduction. This reduction occurs via cis addition to the lower (D) side of intermediates like cis-9,trans-11-octadecadienoic acid. The distribution of deuterium at the reduced carbon atoms suggests that reduction occurs via addition of a proton and hydride ion mediated by an unknown carrier.
Common laboratory preparation and binary mixture (2)Vivek Singh
This document discusses common solvents, laboratory reagents, drug synthesis, and separation of binary mixtures. It provides examples of common solvents like water, acetic acid, acetone, and benzene. Examples of common analytical reagents include Fehling's reagent, Millon's reagent, iodine reagent, and Schiff's reagent. Methods for synthesizing drugs like sodium benzene sulphonate and dibenzal acetone are described. Techniques for separating binary mixtures using differences in physical properties, chemical properties, or volatilities in aqueous solution are also summarized.
This document summarizes Dr. V. A. Chatpalliwar's lecture on separation techniques. It discusses various chromatographic and physical separation methods that can be used to separate binary mixtures and chiral compounds. These include TLC, HPLC, GC, and techniques based on differences in solubility such as extraction with acidic or basic solutions. The document provides guidance on properly selecting and applying separation methods, including considering the properties of the compounds involved and avoiding approaches that could damage or contaminate the samples.
TLC Separation of Cephalosporins on Stannic Arsenate LayersIOSR Journals
Abstract: The chromatographic behaviour of some cephalosporins has been studied on synthetic stannic arsenate layers using citrate and borate buffers as mobile phases. Several ternary and quaternary separations have been achieved. The utility of these separations has been demonstrated for estimation of cephalosporins in blood serum from patients.This method used is simple, rapid ,reproducible and can also be applied in the separation and determination of cephalosporins in other biological samples. The limit of detection was found to be 0.20 μg/l.
This document provides information about qualitative organic analysis procedures at Tumkur University in India. It discusses preliminary tests, determination of physical properties, elemental detection using sodium fusion, solubility testing, and characteristic reactions to identify functional groups of compounds. The document is from the university's Department of Studies and Research in Organic Chemistry and is part of their practical manual for organic chemistry students, covering topics like separation of mixtures, systematic analysis steps, and specific reactions to identify compounds like alcohols and amides.
Oxidative treatment of high explosives contaminated wastewaterRaafat Alnaizy, PhD
1) The document discusses methods for treating wastewater contaminated with high explosives (HE) such as TNT, RDX, and HMX through catalytic/non-catalytic wet oxidation and advanced oxidation processes using ultraviolet light and hydrogen peroxide.
2) Catalytic and non-catalytic wet oxidation experiments were conducted in a batch reactor at moderate pressures and temperatures using a Pt/TiO2 catalyst.
3) Ultraviolet photolysis experiments alone and in combination with hydrogen peroxide were carried out in a glass photoreactor at ambient conditions using a low-pressure mercury lamp.
Solution- and solid-phase synthesis of 4-hydroxy-4,5-dihydroisoxazole derivat...Peter ten Holte
This document describes research into the solution-phase and solid-phase synthesis of 4-hydroxy-4,5-dihydroisoxazole derivatives from enantiomerically pure N-tosyl-2,3-aziridine alcohols. In the solution-phase process, N-tosyl-2,3-aziridine alcohols are directly converted to the corresponding 4-hydroxy-4,5-dihydroisoxazole 2-oxides in one pot through oxidation to the aldehyde followed by tandem nitroaldol-intramolecular cyclization. This provides a direct route to enantiopure 4,5-dihydroisoxazoles in good yields. A solid-
This document provides instructions for measuring chemical oxygen demand (COD) using the dichromate reactor digestion method. Key points include:
- The test measures COD concentrations from 0.7-40 mg/L (ULR range), 3-150 mg/L (LR range), 20-1500 mg/L (HR range), and 200-15,000 mg/L (HR Plus range).
- Samples are digested using COD reagent vials in a heated reactor to oxidize organic compounds. Absorbance of digested samples is then measured colorimetrically.
- Interferences from chloride are removed by mercuric sulfate in the reagent vials. Samples with high chloride must
The document describes the Folch method for extracting lipids. It involves homogenizing tissue in a 2:1 chloroform/methanol mixture. The homogenate is then filtered or centrifuged to separate the liquid phase. This phase is washed with water or saline solution and centrifuged to separate the mixture into upper and lower phases. The upper methanol phase is removed by siphoning and contains polar molecules. The lower chloroform phase contains lipids and is evaporated, leaving only lipids.
Nanoscale perspective on the effect of acid washing carbon catalyst supportsPhilip R. Davies
The document summarizes research on the effect of acid washing carbon catalyst supports. Acid washing with HCl and HNO3 is commonly used to prepare carbon supports for metal catalysts. Using high-resolution techniques, the study found that low concentrations of HCl produced surface features covering 20% of the highly ordered pyrolytic graphite (HOPG) surface. Increasing the HCl concentration led to greater surface coverage. HNO3 had a similar effect but was less effective than HCl at lower concentrations. Models are needed to account for the nanoscale features produced by acid washing.
This document discusses various organic and inorganic compounds found in water. It covers topics like biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids. For BOD and COD, it explains the test procedures and calculations used to measure levels of each compound. It also discusses how temperature affects BOD reaction rates. Inorganic compounds are classified as metals or non-metals. The document provides details on measuring parameters that indicate levels of organic pollution in water samples.
Section 7 organic practicals exam questionsMartin Brown
The document contains questions and information about organic chemistry experiments performed in a school laboratory setting, including:
1) The preparation of soap from lard (animal fat) and sodium hydroxide involves refluxing the reactants with ethanol to allow saponification.
2) Ethanal can be prepared by oxidizing ethanol with sodium dichromate and sulfuric acid. Fehling's test confirms the presence of an aldehyde.
3) Chromatography, including paper, thin-layer, and column chromatography, can be used to separate mixtures like indicators based on differences in compounds' polarity and interactions with the mobile and stationary phases.
This document summarizes a study that determined the concentrations of lead, cadmium, and chromium in spice samples from eastern Ethiopia using atomic absorption spectroscopy. Spice samples of fenugreek, black cumin, garlic, and ginger were collected and digested using microwave digestion with nitric acid and hydrogen peroxide. Lead, cadmium, and chromium concentrations were then measured. The study found detectable levels of all three metals in the samples tested, with the highest lead level found in ginger and the only detectable cadmium found in fenugreek. Microwave digestion was determined to be the optimal sample preparation method compared to dry and wet digestion based on shorter time and smaller deviations in results.
Synthesis of N,N-butyl-d9-methylpyrrolidinium Bis(trifluoromethanesulfonyl)im...Austin Letcher
The production of N,N-butyl-d.-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP Tf2N, an ionic liquid) was desired to study the quenching of lanthanide fluorescence in this ionic liquid. Three steps to the ionic liquid were optimized with non-deuterated reactants. First, 1-methylpyrrolidine was quaternized with 1-bromobutane by an SN2reaction. Cation HPLC was used to determine percent conversion with yields >93%. Second, BMP Br was recrystallized using acetonitrile/ethyl acetate with yields >95%. Third, the anion was exchanged by mixing aqueous Li Tf2N and aqueous BMP Br producing the colorless BMP Tf2N as a separate layer with yields >95%. 'H and 13CNMR verified production of the ionic liquid. Nine extractions with 10:1 (v/v) water:ionic liquid were required to reduce bromide concentration in the aqueous phase below the anion HPLC detection limit of 1.6 ppm. A similar synthesis using perdeuterobutyl bromide proceeded smoothly producing a colorless ionic liquid with an overall 80% yield.
This lab report details qualitative analysis of organic compounds to identify various functional groups. Tests were conducted to detect carboxylic acids, phenols, aldehydes, ketones, and amines. Benzoic acid, salicylic acid, benzophenone, lactose, and 4-aminoacetophenone were supplied for testing. Positive results from bicarbonate and litmus tests confirmed the presence of carboxylic acids. Ferric chloride and Fehling's solution tests identified phenolic and aldehyde groups, respectively. Ketones were detected by the formation of orange crystals with 2,4-dinitrophenylhydrazine. A red precipitate from an azo-dye test
Analysis BOD is an important parameter in identifying the extend of pollution in a water body. This presentation explains the various methods of BOD analysis as per the APHA manual
This document summarizes a study on the aerobic biodegradation of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) by Rhodococcus sp. strain DN22. Key metabolites identified during degradation included nitrite (NO2-), nitrous oxide (N2O), ammonia, and formaldehyde. Isotope labeling experiments revealed that RDX carbon is converted to carbon dioxide and incorporated into a dead-end product with a molecular weight of 119. The proposed degradation pathway involves initial denitration of RDX followed by ring cleavage producing formaldehyde and the metabolite with a molecular weight of 119.
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 using ozone-loaded solvents to extract and destroy organic contaminants in wastewater. Volasil 245, a polydimethylsiloxane, was selected as a suitable solvent based on its properties like high ozone solubility, low toxicity, and resistance to oxidation. Preliminary tests showed Volasil 245 was effective at extracting various organic contaminants from water. Volasil 245 liquid-liquid contact with ozone achieved faster degradation of phenol and chlorophenol in water than conventional gas-liquid contact with ozone. Overall results indicate ozone-loaded solvents may provide an improved method for treating organics in wastewater.
Routine analysis of wastewaters quality parametersArvind Kumar
This document discusses parameters for analyzing waste water quality. It describes the objectives of waste water analysis which include monitoring treatment plant efficiency. Physical analyses examine characteristics like color and odor, while chemical analyses determine substance amounts. Key parameters discussed include biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen, pH, nitrogen, and solids. BOD testing measures oxygen consumed by bacteria breaking down organic matter over time. COD testing uses chemical oxidization to similarly assess ability to consume oxygen. Their ratio provides information on a waste water's biodegradability.
Absence and presence organic and inorganic inhibitorsAlexander Decker
This document summarizes research on the corrosion of copper metal in nitric acid solutions and the inhibitive effects of organic and inorganic additives. Key findings include:
- The rate of copper dissolution increases with increasing nitric acid concentration due to the highly exothermic reaction.
- Organic compounds like phenylhydrazine, urea, and thiourea, as well as inorganic compounds like sodium chromate, sodium tungstate, and sodium phosphate were found to inhibit copper corrosion by adsorbing to the metal surface.
- Inhibition efficiency increased with increasing concentrations of the organic and inorganic additives and followed different sequences based on the chemical structure of the additive.
Application of rapid bioassay method for assessing its water purification by ...inventionjournals
Integral toxicity of four water samples taken from various sources, urban and rural environment was evaluated, and some of the properties of potassium ferrate K2FeO4 as the reagent for chemical purification of water were explored. These data allow to suggest bacterial luminescence based test system for practical use. Thetest system is suitable for rapid evaluation of toxicity of the used for water purification chemical agents, as well as for selection of their effective concentrations and for optimization of treatment time.
Study of the folding and unfolding of proteins adsorbed to a fused silica sur...guestee6b24
This document summarizes a study on the folding and unfolding of cytochrome c proteins adsorbed to a fused silica surface. It introduces cytochrome c, describes solution and surface spectroscopy experiments, and compares experiments using horse and yeast cytochrome c. Specifically, it examines how horse cytochrome c unfolds with increasing alcohol concentration in solution versus on the surface, finding proteins are more protected from denaturation when adsorbed. Similar experiments with yeast cytochrome c show it takes longer to unfold on the surface than in solution.
(THPS BIOCIDE BASE ) moniotoring in sea waterAlsayed Yakoot
This document presents a mechanistic model to predict the degradation of THPS (Tetrakis Hydroxymethyl Phosphonium Sulfate) in seawater under various conditions. Experiments were conducted in bottles with artificial and natural seawater from two locations at different temperatures and pH levels. The data showed that THPS degradation followed first-order kinetics and the rate of degradation increased with higher temperature and pH. An equation was developed to model THPS concentration as a function of time, temperature, and initial concentration based on Arrhenius kinetics. The model was presented in a spreadsheet to calculate THPS concentration given inputs of time, temperature, and initial concentration.
This document summarizes a study on the dehydration of sodium carbonate decahydrate to monohydrate in a fluidized bed reactor. The researchers investigated the kinetics of the reaction at temperatures between 15-30°C and explored the effects of particle size, bed mass, and gas velocity on the dehydration rate. They developed a rate law formula to estimate dehydration rates needed for fluidized bed drying unit design. The produced monohydrate was analyzed for changes in pore volume and surface area.
This document describes a new method for producing bleach using a zero-gap electrolysis cell with three compartments separated by ion exchange membranes. The goal is to generate hypochlorous acid at high levels in the anode compartment by continuously adjusting the pH between 4.5-5.5. Caustic soda would be produced in the cathode compartment while brine is supplied to the central compartment. Hypochlorous acid from the anode compartment would then be neutralized with sodium hydroxide to produce bleach with active chlorine contents close to 1.8%. The document discusses membrane properties, operating conditions, and results obtained with this new method for producing higher concentration bleach using a zero-gap electrolysis cell.
The document provides an overview of catalysis. It defines a catalyst as a substance that speeds up a chemical reaction but is not consumed by the reaction. It discusses different types of catalysis including homogeneous catalysis where the catalyst is in the same phase as the reactants, and heterogeneous catalysis where the catalyst is in a different phase. The document also covers catalyst characterization techniques, factors that can lead to catalyst deactivation, and methods for catalyst regeneration. Examples are provided throughout to illustrate catalysis concepts and applications.
This document provides instructions for measuring chemical oxygen demand (COD) using the dichromate reactor digestion method. Key points include:
- The test measures COD concentrations from 0.7-40 mg/L (ULR range), 3-150 mg/L (LR range), 20-1500 mg/L (HR range), and 200-15,000 mg/L (HR Plus range).
- Samples are digested using COD reagent vials in a heated reactor to oxidize organic compounds. Absorbance of digested samples is then measured colorimetrically.
- Interferences from chloride are removed by mercuric sulfate in the reagent vials. Samples with high chloride must
The document describes the Folch method for extracting lipids. It involves homogenizing tissue in a 2:1 chloroform/methanol mixture. The homogenate is then filtered or centrifuged to separate the liquid phase. This phase is washed with water or saline solution and centrifuged to separate the mixture into upper and lower phases. The upper methanol phase is removed by siphoning and contains polar molecules. The lower chloroform phase contains lipids and is evaporated, leaving only lipids.
Nanoscale perspective on the effect of acid washing carbon catalyst supportsPhilip R. Davies
The document summarizes research on the effect of acid washing carbon catalyst supports. Acid washing with HCl and HNO3 is commonly used to prepare carbon supports for metal catalysts. Using high-resolution techniques, the study found that low concentrations of HCl produced surface features covering 20% of the highly ordered pyrolytic graphite (HOPG) surface. Increasing the HCl concentration led to greater surface coverage. HNO3 had a similar effect but was less effective than HCl at lower concentrations. Models are needed to account for the nanoscale features produced by acid washing.
This document discusses various organic and inorganic compounds found in water. It covers topics like biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids. For BOD and COD, it explains the test procedures and calculations used to measure levels of each compound. It also discusses how temperature affects BOD reaction rates. Inorganic compounds are classified as metals or non-metals. The document provides details on measuring parameters that indicate levels of organic pollution in water samples.
Section 7 organic practicals exam questionsMartin Brown
The document contains questions and information about organic chemistry experiments performed in a school laboratory setting, including:
1) The preparation of soap from lard (animal fat) and sodium hydroxide involves refluxing the reactants with ethanol to allow saponification.
2) Ethanal can be prepared by oxidizing ethanol with sodium dichromate and sulfuric acid. Fehling's test confirms the presence of an aldehyde.
3) Chromatography, including paper, thin-layer, and column chromatography, can be used to separate mixtures like indicators based on differences in compounds' polarity and interactions with the mobile and stationary phases.
This document summarizes a study that determined the concentrations of lead, cadmium, and chromium in spice samples from eastern Ethiopia using atomic absorption spectroscopy. Spice samples of fenugreek, black cumin, garlic, and ginger were collected and digested using microwave digestion with nitric acid and hydrogen peroxide. Lead, cadmium, and chromium concentrations were then measured. The study found detectable levels of all three metals in the samples tested, with the highest lead level found in ginger and the only detectable cadmium found in fenugreek. Microwave digestion was determined to be the optimal sample preparation method compared to dry and wet digestion based on shorter time and smaller deviations in results.
Synthesis of N,N-butyl-d9-methylpyrrolidinium Bis(trifluoromethanesulfonyl)im...Austin Letcher
The production of N,N-butyl-d.-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (BMP Tf2N, an ionic liquid) was desired to study the quenching of lanthanide fluorescence in this ionic liquid. Three steps to the ionic liquid were optimized with non-deuterated reactants. First, 1-methylpyrrolidine was quaternized with 1-bromobutane by an SN2reaction. Cation HPLC was used to determine percent conversion with yields >93%. Second, BMP Br was recrystallized using acetonitrile/ethyl acetate with yields >95%. Third, the anion was exchanged by mixing aqueous Li Tf2N and aqueous BMP Br producing the colorless BMP Tf2N as a separate layer with yields >95%. 'H and 13CNMR verified production of the ionic liquid. Nine extractions with 10:1 (v/v) water:ionic liquid were required to reduce bromide concentration in the aqueous phase below the anion HPLC detection limit of 1.6 ppm. A similar synthesis using perdeuterobutyl bromide proceeded smoothly producing a colorless ionic liquid with an overall 80% yield.
This lab report details qualitative analysis of organic compounds to identify various functional groups. Tests were conducted to detect carboxylic acids, phenols, aldehydes, ketones, and amines. Benzoic acid, salicylic acid, benzophenone, lactose, and 4-aminoacetophenone were supplied for testing. Positive results from bicarbonate and litmus tests confirmed the presence of carboxylic acids. Ferric chloride and Fehling's solution tests identified phenolic and aldehyde groups, respectively. Ketones were detected by the formation of orange crystals with 2,4-dinitrophenylhydrazine. A red precipitate from an azo-dye test
Analysis BOD is an important parameter in identifying the extend of pollution in a water body. This presentation explains the various methods of BOD analysis as per the APHA manual
This document summarizes a study on the aerobic biodegradation of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) by Rhodococcus sp. strain DN22. Key metabolites identified during degradation included nitrite (NO2-), nitrous oxide (N2O), ammonia, and formaldehyde. Isotope labeling experiments revealed that RDX carbon is converted to carbon dioxide and incorporated into a dead-end product with a molecular weight of 119. The proposed degradation pathway involves initial denitration of RDX followed by ring cleavage producing formaldehyde and the metabolite with a molecular weight of 119.
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 using ozone-loaded solvents to extract and destroy organic contaminants in wastewater. Volasil 245, a polydimethylsiloxane, was selected as a suitable solvent based on its properties like high ozone solubility, low toxicity, and resistance to oxidation. Preliminary tests showed Volasil 245 was effective at extracting various organic contaminants from water. Volasil 245 liquid-liquid contact with ozone achieved faster degradation of phenol and chlorophenol in water than conventional gas-liquid contact with ozone. Overall results indicate ozone-loaded solvents may provide an improved method for treating organics in wastewater.
Routine analysis of wastewaters quality parametersArvind Kumar
This document discusses parameters for analyzing waste water quality. It describes the objectives of waste water analysis which include monitoring treatment plant efficiency. Physical analyses examine characteristics like color and odor, while chemical analyses determine substance amounts. Key parameters discussed include biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen, pH, nitrogen, and solids. BOD testing measures oxygen consumed by bacteria breaking down organic matter over time. COD testing uses chemical oxidization to similarly assess ability to consume oxygen. Their ratio provides information on a waste water's biodegradability.
Absence and presence organic and inorganic inhibitorsAlexander Decker
This document summarizes research on the corrosion of copper metal in nitric acid solutions and the inhibitive effects of organic and inorganic additives. Key findings include:
- The rate of copper dissolution increases with increasing nitric acid concentration due to the highly exothermic reaction.
- Organic compounds like phenylhydrazine, urea, and thiourea, as well as inorganic compounds like sodium chromate, sodium tungstate, and sodium phosphate were found to inhibit copper corrosion by adsorbing to the metal surface.
- Inhibition efficiency increased with increasing concentrations of the organic and inorganic additives and followed different sequences based on the chemical structure of the additive.
Application of rapid bioassay method for assessing its water purification by ...inventionjournals
Integral toxicity of four water samples taken from various sources, urban and rural environment was evaluated, and some of the properties of potassium ferrate K2FeO4 as the reagent for chemical purification of water were explored. These data allow to suggest bacterial luminescence based test system for practical use. Thetest system is suitable for rapid evaluation of toxicity of the used for water purification chemical agents, as well as for selection of their effective concentrations and for optimization of treatment time.
Study of the folding and unfolding of proteins adsorbed to a fused silica sur...guestee6b24
This document summarizes a study on the folding and unfolding of cytochrome c proteins adsorbed to a fused silica surface. It introduces cytochrome c, describes solution and surface spectroscopy experiments, and compares experiments using horse and yeast cytochrome c. Specifically, it examines how horse cytochrome c unfolds with increasing alcohol concentration in solution versus on the surface, finding proteins are more protected from denaturation when adsorbed. Similar experiments with yeast cytochrome c show it takes longer to unfold on the surface than in solution.
(THPS BIOCIDE BASE ) moniotoring in sea waterAlsayed Yakoot
This document presents a mechanistic model to predict the degradation of THPS (Tetrakis Hydroxymethyl Phosphonium Sulfate) in seawater under various conditions. Experiments were conducted in bottles with artificial and natural seawater from two locations at different temperatures and pH levels. The data showed that THPS degradation followed first-order kinetics and the rate of degradation increased with higher temperature and pH. An equation was developed to model THPS concentration as a function of time, temperature, and initial concentration based on Arrhenius kinetics. The model was presented in a spreadsheet to calculate THPS concentration given inputs of time, temperature, and initial concentration.
This document summarizes a study on the dehydration of sodium carbonate decahydrate to monohydrate in a fluidized bed reactor. The researchers investigated the kinetics of the reaction at temperatures between 15-30°C and explored the effects of particle size, bed mass, and gas velocity on the dehydration rate. They developed a rate law formula to estimate dehydration rates needed for fluidized bed drying unit design. The produced monohydrate was analyzed for changes in pore volume and surface area.
This document describes a new method for producing bleach using a zero-gap electrolysis cell with three compartments separated by ion exchange membranes. The goal is to generate hypochlorous acid at high levels in the anode compartment by continuously adjusting the pH between 4.5-5.5. Caustic soda would be produced in the cathode compartment while brine is supplied to the central compartment. Hypochlorous acid from the anode compartment would then be neutralized with sodium hydroxide to produce bleach with active chlorine contents close to 1.8%. The document discusses membrane properties, operating conditions, and results obtained with this new method for producing higher concentration bleach using a zero-gap electrolysis cell.
The document provides an overview of catalysis. It defines a catalyst as a substance that speeds up a chemical reaction but is not consumed by the reaction. It discusses different types of catalysis including homogeneous catalysis where the catalyst is in the same phase as the reactants, and heterogeneous catalysis where the catalyst is in a different phase. The document also covers catalyst characterization techniques, factors that can lead to catalyst deactivation, and methods for catalyst regeneration. Examples are provided throughout to illustrate catalysis concepts and applications.
CHE235L4Spring2017.pdf
FW
(g/mol)
mp (
o
C) bp (
o
C) mmol mass (g)
density
(g/mL)
volume
(mL)
N/A
N/A
bismuth(III) nitrate pentahydrate N/A N/A N/A N/A
sodium chloride, saturated (brine) N/A N/A N/A N/A N/A
ethyl acetate N/A N/A
cis -1,2-cyclohexanediol N/A N/A N/A
trans -1,2-cyclohexanediol, (±) N/A N/A N/A
Prelab 4: Green Lewis Acid-Catalyzed Hydrolysis of Cyclohexene Oxide
Name:
Reaction equation:
Note: For those reagents that are in solution, the FW, mmol, and mass columns refer to the solute in the
solution.
Limiting reagent:
Reagent Table
water
Theoretical yield:
Chemical
cyclohexene oxide
EXPERIMENT #4
GREEN LEWIS ACID-CATALYZED HYDROLYSIS OF CYCLOHEXENE OXIDE
Introduction:
Epoxides are three-membered ethers. They are special because unlike most ethers, they can react
with nucleophiles to form a new bond between carbon and the nucleophile and break a bond
between that carbon and oxygen. This ring-opening reaction makes epoxides versatile functional
groups for organic synthesis. (In fact epoxide is the functional group that makes epoxy resins
possible.)
Scheme 1. Ring opening of an epoxide in the presence of a nucleophile.
Ring-opening of the epoxide can occur under basic or acidic conditions. Under basic conditions,
the reaction is similar to an SN2 reaction so that the nucleophile attacks the less substituted carbon
of an unsymmetrical epoxide by backside attack. Sodium ethoxide reacts with this epoxide in the
following reaction.
Scheme 2. Ring opening of an unsymmetrical epoxide under basic conditions.
Under acidic conditions, the reaction is more complicated. It is similar to an SN2 reaction because
the nucleophile reacts by backside attack. However, because there is partial positive charge on the
Reference Material:
MAHHS Chapter 1: Safety in the Laboratory
MAHHS Chapter 2: Protecting the Environment
MAHHS Chapter 3: Laboratory Notebooks and Prelaboratory Information
MAHHS Chapter 4: Laboratory Glassware
MAHHS Chapter 5: Measurements and Transferring Reagents
MAHHS Chapter 10: Filtration
MAHHS Chapter 11: Extraction
MAHHS Chapter 12: Drying Organic Liquids and Recovering Reaction Products
MAHHS Chapter 17: Thin-Layer Chromatography, especially section 17.8
MAHHS Chapter 20: Infrared Spectroscopy
Klein Chapter 14: Ethers and Epoxides; Thiols and Sulfides
three atoms of the epoxide ring, the nucleophile attacks where the partial positive charge is more
stabilized, the more substituted carbon of an unsymmetrical epoxide. Ethanol in the presence of
sulfuric acid reacts with this epoxide in the following reaction.
Scheme 3. Ring opening of an unsymmetrical epoxide under acidic conditions.
While sulfuric acid is an inexpensive acid catalyst, it is difficult to handle. It is very corrosive and
can cause severe burns. In addition, it is viscous, which makes it difficult to handle on the scale of
the reactions perfor ...
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Secado dmso desiccant efficiency in solvent drying. 3.
1. Subscriber access provided by TEXAS A&M UNIV COLL STATION
The Journal of Organic Chemistry is published by the American Chemical Society.
1155 Sixteenth Street N.W., Washington, DC 20036
Desiccant efficiency in solvent drying. 3. Dipolar aprotic solvents
David R. Burfield, and Roger H. Smithers
J. Org. Chem., 1978, 43 (20), 3966-3968• DOI: 10.1021/jo00414a038 • Publication Date (Web): 01 May 2002
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2. 3966 J.Org. Chem., Vol.43, No. 20,1978 Notes
Other acetals which are commonly used as protectinggroups for alcohols
are the tetrahydropyranylether (ref 4, p 104), ethoxyethyl ether (S. Chladek
and J. Smtt, Chem. Ind. (London), 1719 (1964)), 2-methoxyisopropylether
(ref 4, p 107),and 4-methoxytetrahydropyranylether (ref4, p 108).Removal
of all of these groups can be accornpllshedwith dilute, aqueous acid. They
are prepared from the corresponding vinyl ether with acidcataiysis. The
methoxymethylether,' as well as our tert-butoxymethyl ether, is prepared
from the chloro ether with base catalysis.
See, for example, (a) the synthesis of chloromethyl methyl ether: C. S.
Marvel and P. K. Potter, "Organic Synthesis", Collect. Vol. I, 2nd ed, A.
H. Blatt, Ed., Wiley, New York, N.Y., 1941, p 377; (b) the preparation of
methoxyethyl chloromethyl ether: E. J. Corey, J.-L. Gras, and P. Ulrich,
Tetrahedron Lett., 809 (1976); and (c)a review on a-halo ethers: L. Sum-
mers, Chem. Rev., 55, 301 (1955).
Ethers are halogenatedon the (Y carbon: M. L. Poutsma in "Methods in Free
Radical Chemistry", Vol. 1, E. S.Huyser,Ed., Marcel Dekker, New York,
N.Y., 1969, p 137.
Methods for the free-radical halogenationof organic compounds have been
reviewed: E. S.Huyser, Synthesis, 7 (1970).
Sulfuryl chloride has been used to chlorinate tetrahydrofuran(THF): C. G.
Kruse, N. L. J. M. Broekhof, and A. van der Gen, Tetrahedron Lett., 1725
(1976).
All attempts to isolate the chloro ether by concentration have led to de-
composition.
J. F. Norris and G. W. Rigby, J. Am. Chern. SOC.,54, 2088 (1932).
There is no reaction at 0 O C after 4 h but a satisfactory reaction rate is
obtained at room temperature. The water bath is used for cooling purposes
only.
The 'H NMR spectra of the tert-butoxymethyl ethers show singlets at 6
4.1-4.7 (2 H)and 1.2-1.25 (9 H).The corresponding l3CNMR spectra are
also consistent with the proposed structures. For example, the acetal and
quaternary carbons are found at 6 89.248 and 74.251, respectively, for
the benzyl alcohol acetal and 690.038 and 74.068, respectively, for the
1-hexanolacetal.
Desiccant Efficiency in Solvent Drying. 3.
Dipolar Aprotic SolventslJ
David R. Burfield*and Roger H. Smithers
Department of Chemistry, University of Malaya,
Kuala Lumpur 22-11, Malaysia
Received May 2, 1978
It is generally acknowledged that dipolar aprotic solvents
are the media of choice in some reactions and are unique in
facilitating others.3 The special solvent effects of molecules
such as DMF and Me2SO are attributable to their large di-
electric constants coupled with the absence of solvation by
hydrogen bonding and typically manifest themselves in
properties such as poor anion solvation, voracious cation
solvation, and a marked hydrophilicity. For the chemist, this
latter feature is unfortunate since small amounts of water in
these systems can diminish314their nucleophilicity and may
even be hazardous to some operations.5 The drying of these
solvents is thus of paramount importance, but in these cases,
as previously,' the chemical literature contains little reliable
quantitative data.
We have recently developed a method of solvent water assay
which utilizes a tritiated water tracer for the determination
of water content.6 The method circumvents many of the
problems encountered in other assay methods and has pro-
vided some new correlations on the efficiency of desiccants.lS*
For example,it has been shown that, rather surprisingly,the
efficiency of a given desiccant is strongly dependent upon the
solvent type,' and there is thus much uncertainty in extrap-
olating generalizations from one solvent type to another.
The method has now been applied to the desiccation of the
dipolar aprotics acetone, DMF, MeZSO, and HMPT. Since the
dielectric constants of these solvents range between 20.7
(acetone) and 46.7 (MeZSO),their rigorous desiccation is ex-
pected to be difficult.
Results and Discussion
Drying of Hexamethylphosphoric Triamide (HMPT).
Caution! HMPT is a suspected carcinogen. Although in re-
cent years the favored desiccant for HMPT appeared to be
calcium h ~ d r i d e , ~drying has also been previously accom-
plished with alkali metal^,^^^ alkali metal earth oxides,sand
4A9*and 13Xgbmolecular sieves.
The results with the siccatives summarized in Table I are
largely self-evident,but the followingpoints are worth noting.
The extreme resistance to desiccation is demonstrated by the
impossibility of obtaining super-dryloHMPT under any of
the conditions used here. Even sequential drying,ll which was
previously found to be effective with acetonitrile,2 falls short
in this case. The use of sodium-potassium alloy as a drying
agent seems questionable in view of the thermal instability
of solutions of alkali metals in solvents of this type.lZ
Since phosphorus pentoxide causes loss of material through
side reactions, the best procedure for drying HMPT appears
to be distillation from calcium hydride followed by storage
over molecular sieves.
Drying of DimethylformamideOne sources observes that
it is doubtful whether distillation alone can remove water from
this solvent and recommends a chemical method for the
elimination of protonic impurities. 4A molecular sieves, alu-
mina, potassium hydroxide, and calcium hydride have all been
endorsed as siccativess for DMF.
The results in Table I1indicate the powerful hydrophilicity
of this solvent,although sequential drying with 3A sieves al-
most achieves super-dryness. Interestingly, and contrary to
an earlier suggestion,'3 while some of the basic dessiccants
investigated are totally inept, e.g., alumina and potassium
carbonate, others such as calcium hydride and potassium
hydroxide achieve quite reasonable drying levels. Also, al-
though seldom advocated for use in this circumstance, phos-
phorus pentoxide is a commendable desiccant. For DMF,
however, barring impurities other than water, by far the
Table I. Efficiency of Desiccants in the Drying"of HMPTb
residual solvent water content, ppm
desiccant 6 h 24 h 72 h 144h other conditions
p205 184OC 22d
CaHz 1750 857 347 248 80d
Bz03 190e
3A molecular sieves 1380 595 307 239
4A molecular sieves 1167 610 344 269 295
KOH (powdered) 1380 840 404 321f
Na-K 162Od.g
BaO 2190 1540 1040
CaO 2360 2034 1890 1380
A1203 2134
a Static drying modes unless otherwisespecified.
Cas04 2080
Desiccantloading 5% w/v; initialwater content 2620 ppm (0.262% w/w). Strongly
Distilled sample. e Stirringfor 24 h followed by distillation.f Sequentiallydried sample,72 h. Significantquantitiescolored solution.
of dimethylamine are released on distillation.
0022-3263/78/1943-3966$01.00/0 0 1978 American Chemical Society
3. Notes J. Org. Chem., Vol.43, No. 20,1978 3967
Table 11.Efficiency of Desiccants in the Drying"of
DMFb
residual solvent water
content, ppm
other
desiccant 6 h 24h 72h conditions
3A molecular sieves 500 167 98 1.5c
pzo6 879 105 2 d
CaH2 641 227 102 94d
4A molecular sieves 454 134 108
KOH (powdered) 1360 1110 303
B203 890e
BaO 2060 1520 1140
CaO 2090
A1203 1970
Cas04 2310 2030 1420
KzC03 2500
a Staticdrying modes unless otherwise specified. Desiccant
loading 5% w/v; initial water content 2860 ppm (0.286%w/w).
Sequentially dried sample, 72h. Distilled Sample. e Stirring
for 24 h followed by distillation.
simplest and most effective method is sequential drying with
3A molecular sieves.
Drying of Dimethyl Sulfoxide (MezSO).Although cal-
cium hydride14aand molecular sieves14bappear to be approved
desiccants,the drying of Me2SO has also been accomplished
with a large variety of other siccatives.8Calcium sulfate, alkali
earth metal oxides, alkali metal hydroxides, alumina, and,
surprisingly perhaps, fractional distillation alone15have all
been utilized.
Perhaps the most unexpected result (Table 111) is that
fractional distillation, discarding the first 20?hof the distillate,
affords desiccation of similar magnitude to that obtained with
molecular sieves!This result is most surprising in view of the
high dielectric constant and hygroscopicity of MezSO.
The interpretation of other results for MezSO is not so
straightforward. For many of the basic desiccants, e.g.,calcium
hydride and calcium and barium oxides, initial dehydration
is followedby an increase in apparent water content, and this
indicates a base-catalyzed exchange between the acidic a
protons of Me2SO and labeled water. This suggestion is sup-
ported by a desiccation experiment with powdered potassium
hydroxide which gave very little apparent drying. In this case,
standing for 2 or 3 h over the desiccant produced yellow so-
lutions, most likely indicating the presence of the dimsyl ion,
which would of course lead to labeled solvent through ex-
change processes.
Although the resultswith the basic desiccants are therefore
not very conclusive,a necessary corollary in the case of calcium
hydride is, however,that drying is relatively slow,and perhaps
not very efficient. A similar result for this desiccant was noted
earlier with acetonitrile.'
In summary, although phosphorus pentoxide gave the best
drying, it also induced significant decomposition, and the
method of choice for Me2SO would appear to be initial frac-
tional distillation followed by sequential drying with molec-
ular sieves.
Drying of Acetone. Acetone has been dried with a wide
spectrum of desiccants.8 Thus, alumina, calcium chloride,
phosphorus pentoxide, and 4A molecular sieves,16as well as
calcium and (anhydrous) cupric sulfate, have all been used.
Since acetone has the lowest dielectricconstant of the sol-
vents investigated here, it might be predicted that its drying
should be relatively easy. In fact, in many respects the drying
of acetone proved tobe the most difficult case.As with MezSO,
the root of the difficulty is the acidic a protons, which in this
case compounds the drying problem not only by inflating
apparent water content by exchange process but also by
providing a pathway to self-condensation through enol in-
termediates. This facet of acetone chemistry makes the choice
of a successfuldesiccant a delicate process. As Table IV shows,
mild siccatives such as calcium sulfate are inept; more potent
desiccants such as molecular sieves exhibit a short initial
drying action but thereafter actually cause disastrous in-
creases in water content by displacement of the condensation
equilibrium. This interpretation was confirmed for molecular
sieves and other basic desiccants such as barium oxide by gas
chromatographic analysis which demonstrated the presence
of mesityl oxide in the dried solvent (seeTable IV).
In summary, while both cupric sulfate and 3A molecular
sieves are clearly at least useful preliminary desiccants, the
agent par excellence for acetone is powdered boric anhydride.
Using stirring and sequentialdrying conditions, this siccati
gave a solvent containing only 18ppm of water and caused
detectable condensation. In fact, the true water content
likely to be lower as even with the premise that drying OCCL
considerably faster than other processes, some labeling via t
enol surely occurs on preparation of the standard wet sol
tion.
In view of the remarkable efficiency of this desiccant f
acetone and acetonitrile,l it is puzzling that boric anhydri
is not particularly outstanding for other members of this ser
(Tables 1-111).This finding emphasizes once more the danger
in assuming the existenceof any kind of absolute scale in the
efficiency of desiccants for solvent drying.
Table 111. Efficiency of Desiccants in the Dryingaof MezSOb
residual solvent water content, ppm
desiccant 6 h 24 h 72 h 144h other conditions
4A niolecular sieves 978 471 332 318 1 o c
3A molecular sieves 1050 448 269 226
none 261
P205 1.4e3f
B203 897g
CaH2 1560 1820 1740 1802e
BaO 1450 1330 1770 2251
CaO 2060 1740 1800
A12013 1840 1900 1920
KOH (powdered) 2130h 2190e
Cas04 2140
KzCQ3 2280 2200
Static drying modes unless otherwise specified. Desiccant loading 5%w/v; initial water content 2560 ppm (0.256%w/w). Se-
quentiallydried sample,72 h. d Fractionally distilled sample. e Distilled sample. f Contaminated by decompositionproducts. g Stirring
for 24 h followed by distillation. Yellow colored solutions.
4. 3968 J. Org. Chem., Vol.43, No. 20, 1978 Notes
Table IV. Efficiency of Desiccants in the DryingDof
Acetone
residual solvent water
content, ppm
other
desiccant 6 h 24 h 72 h conditions
Bz03 i8C.d
47c.e
107f
3A molecular sieves 115 152 322g 322h
CuSO4 (anhydrous) 1920 972 579 1700h
Cas04 1590 1600
BaO 1910 1870'
pzo5 j 1970f
KzC03 2057 2250
Desiccant
loading 5% w/v; initial water content 2710 ppm (0.271%w/w),
unless specified otherwise. c Initial water content 2890 ppm
(0.289%w/w). d Stirred, distilled, and sequentially dried, 24 h.
e Stirredfor 24 h anddistilled. f Dried for 24hand then distilled.
g Contamination (2%)by mesityl oxide. Fractionated sample.
i Contamination (12%) by mesityl oxide. j Brown-black solu-
tions.
4A molecular sieves 331 887 1720
a Staticdrying modes unless specified otherwise.
Experimental Section
Desiccants. Details of the source,activation, and handlingof most
of the desiccants havealready been described.' Reagentgrade cupric
sulfate wasactivated by heating at 320"Cfor 15h before use.Barium
and calciumoxideswere of reagent grade, and a fresh batch wasused
directly without activation.
Solvents,DMF, MeZSO, and HMPT were commercialsynthetic
gradesof 99%purity (Merck).Acetone wasof analyticalgrade (M&B).
All solvents were rigorouslypurified by standard methods.*
HMPT and Me2SO were treated by standing over barium oxide
overnight, followed by filtration, distillation from calcium hydride,
and subsequentstorageover20% w/v 4A molecularsieves.MezSOhad
bp 74.5-75.0 O C at 12 mmHg,and HMPThad bp 89.0-89.5 "C at-3
mmHg.
CommercialDMF was allowed to stand over 4A molecular sieves
overnight and was filtered,distilled fromphosphorus pentoxide (bp
55.8-56.0 "C at 20 mmHg),allowed to stand over anhydrouspotas-
sium carbonate, and subsequentlystored over 4A molecular sieves.
Analytical grade acetone was allowed to stand over anhydrous
potassium carbonate for one day and then over 4A molecular sieves
overnight. Fractionation gave material, bp 56.2 OC, which was not
stored but used immediately. Gas chromatographic analysis of this
material showed it to be free of impurities.
Techniques. The procedureused for HMPTservesasanexample.
A stock solutionof HMPT containing 2620ppm of labeledwater was
prepared by the additionof 0.50 gof tritiated water, specificactivity
0.5 mCi/mL, to the appropriate mass of purified rigorously dried
HMPT. Aliquotsof the stock solution (15.0i0.1mL)were syringed
directly ontothe appropriatedesiccantcontained in a 25mL clear-fit
round-bottom flask,which was immediatelystoppered. Experiments
wereconductedat ambienttemperatures (26-30 "C).Wherespecified,
samples were stirred magnetically. Aliquots (1.00 f 0.02 mL) were
taken at time intervals asspecified in TableI and assayeddirectlyby
liquid scintillation counting, as previously Where nec-
essary,viz.,in the caseof coloredsolutionsor suspectedcontamination
by soluble desiccant residues, samples were distilled before assay.
Sequential drying2 was accomplished by decanting monosiccated
solvent onto a fresh charge of 5%w/v desiccant. Sampling was then
effected at the time intervals given in the table footnotes.
Registry No.-HMPT, 680-31-9;DMF,68-12-2;MeZSO,67-68-5;
acetone, 67-64-1.
References and Notes
(1)Part I: D.R. Burfield, K.H. Lee, and R. H. Smithers, J. Org. Chem., 42,3060
(1977).
(2)For Part 2,see D. R. Burfield. G. H. Gan,and R. H. Smithers, J. Appl. Chem.
Biotechnol., 28,23 (1978).
(3)See, for example, Heinz Becker et ai., "Organicum, Practical Handbook
of Organic Chemistry", translated by B. J. Hazard, Pergamon Press,
Braunschweig. 1973,pp 185.190.See also L. F. Fieser and M. Fieser.
"Reagents for Organic Synthesis", Vol. 1-5,Wiley, New York. N.Y., 1967,
0022-3263/78/1943-3968$01.00/0
1969,1972,1974and 1975.
(4)For an interesting recent study involving Me2SO-H20mixtures, see L. F.
Blackwell and J. L. Woodhead, J. Chem. Soc.. Perkin Trans. 2, 1218
(1975).
(5)The reactionof sodium hydride with Me2S0hasbeenreportedto sometimes
give rise to violent explosions: inter alia, see L. Brandsma, "Preparative
Acetylenic Chemistry", Elsevier, Amsterdam, 1971,p 24.However, in our
hands, the same reaction has been carried out a number of times using
stringently dried solvent with no untowardeffects. While thecause of these
accidents remains undetermined, it is noteworthy that the equilibrium water
content of Me2S0is lo%, and it thus seems not unlikely that the origin
of these mishaps may lie in the use of insufficiently dried solvents.
(6)D. R. Burfield, Anal. Chem., 48,2285 (1976).
(7)See,for example, B. M. Trost and Y. Tamaru, J. Am. Chem. Soc.,99,3101
(1977).
(8)See references contained in J. A. Riddick and W.B. Bunger, "Organic
Solvents", 3rd ed., Wiley-lnterscience, New York, N.Y., 1970.
(9)(a) F. Trondlin and C. Ruchardt, Chem. Ber., 110, 2949 (1977);(b) T. J.
Wallace and A. Schriesheim, Tetrahedron, 21,2271 (1965).
(10)Here, as the term super-dry denotes solvents containing less
than 1 ppm of water.
(11) See Experimental Section.
(12)C. A. Young and R. R. Dewald, J. Chem. Soc., Chem. Commun., 186
(1977).
(13)See S.S.Pizey, "Synthetic Reagents", Vol. 1. Ellis Horwood Ltd., Chi-
Chester, 1974.This author reportsthat the use of calcium hydride and other
basic desiccants in the drying of DMF could produce significant amounts
of dimethylamine. However, the presence of this amine would give rise
to inflated apparent water contents, and the values observed here, both
for statically dried and distilled samples, suggest that this side reaction is
of minor importance for these desiccants.
(14) (a) D.Martin and H. G. Hauthal, "Dimethyl Sulphoxide", translated by E.
S. Halberstadt,Wiley-Halsted, New York, N.Y., 1975.(b)H. E. Baumgarten.
Ed.. "Organic Syntheses", Collect. Vol. 5,Wiley, New York. N.Y., 1973,
pp 243,756.
(15) W. H. Smyrl and C. W. Tobias, J. Electrochem. Soc., 115, 33 (1968).
(16)R. L. Meeker, F. Critchfield, and E. T. Bishop, Anal. Chem., 34, 1510
(1962).
3,4-Dimethyl-cis- bicyclo[3.3.0]-3-octene-2,8-dione:
A Potentially Useful Pentalenolactone Synthon
Martha L. Quesada, Richard H. Schlessinger,*and
William H. Parsons
Department of Chemistry, University of Rochester,
Rochester, New York 14627
Received March 13.1978
Pentalenolactone (1) is an acidic lipophylicantibiotic iso-
lated from the fermentation broth of Streptomyces UC 5319
-1
which exhibits inhibitory activity against nucleic acid syn-
thesis in bacterial cells.1t2Both the novel structural nature of
pentalenolactone together with its biological activity
prompted us to consider possible routes to the synthesis of this
molecule.
Inspection of the literature revealed a number of potential
pentalene ~ y n t h o n s , ~the most interesting of which was the
pentalenedione2 reported first by Stetter4and more recently
0
32 --
by E a t ~ n . ~The salientfeatureof both the Stetter and Eaton
routes was the base-induced internal Claisen condensation
of the ester 3, which in Eaton's hands gave an excellentyield
of the dione 2. These data inspired us to consider the possi-
0 1978American Chemical Society