The document describes a procedure for reducing vanillin to vanillyl alcohol using sodium borohydride. Sodium borohydride is a mild reducing agent that can be used in aqueous or alcoholic solutions, allowing for a low solvent synthesis. The reaction involves dissolving vanillin in a solvent like ethanol and adding sodium borohydride to reduce the carbonyl group to an alcohol. Excess sodium borohydride is decomposed by acidifying, and the resulting vanillyl alcohol product can be purified using techniques like recrystallization. The reduction procedure provides a renewable route to synthesize vanillyl alcohol from lignin-derived vanillin.
The complex metal hydrides are generally salts in which the anions contain hydrides
They typically contain more than one type of metal or metalloid and can be soluble or react with water
General Formula of Complex Metal Hydrides- MxM'yHn
where, M= Alkali metal; M'= Metal/Metalloid
This document discusses the properties of alcohols, phenols, ethers, and thiols. Alcohols contain a hydroxyl group and are polar due to the electronegativity difference between oxygen and hydrogen. They have higher boiling points than hydrocarbons due to hydrogen bonding. Phenols contain a hydroxyl group attached to a benzene ring and are somewhat soluble in water. Ethers have the general formula R-O-R and have polar C-O bonds but do not form hydrogen bonds. Thiols contain a sulfhydryl group and are similar to alcohols but with sulfur replacing oxygen.
This document summarizes various methods of chemical reduction. It discusses heterogeneous catalytic hydrogenation using platinum, palladium, nickel, and copper chromite catalysts. Alkenes are converted to alkanes, and unsaturated functional groups like carbonyls, nitriles, and aromatics can be reduced. Homogenous hydrogenation uses soluble transition metal complexes as catalysts, like rhodium and ruthenium. Rhodium complexes selectively reduce double bonds without affecting other functional groups. Reduction of alkynes, aromatics, aldehydes, ketones, nitriles, oximes and nitro compounds are also summarized. The mechanisms of catalytic and homogenous hydrogenation are provided.
This document provides information about amination by reduction. It discusses various reduction methods used to synthesize amines including metal and acid reduction, metal hydrides, sulfides, and electrolysis. Metal and acid reduction, specifically the Bechamp method using iron and hydrochloric acid, is described in detail. An example process for the production of aniline via the reduction of nitrobenzene is outlined, including reaction details and equipment used. Amines produced by these reductive methods are important intermediates for chemicals, dyes, pharmaceuticals, and other industrial products.
1. Lithium aluminum hydride (LiAlH4) is a strong reducing agent that can reduce a wide range of functional groups like aldehydes, ketones, esters, acids, and nitriles to alcohols. It works by donating hydride ions (H-) that react with electrophilic carbons.
2. Sodium borohydride (NaBH4) is a milder reducing agent that can only reduce aldehydes and ketones to alcohols. It is soluble in alcohol and water, making it advantageous for polar substrates.
3. Diborane (B2H6) adds to carbon-carbon double bonds in a stere
This document discusses various types of reduction reactions including:
1) Catalytic hydrogenation using metals like Pt, Pd, Ni, Ru, Rh to reduce double and triple bonds.
2) Hydride transfer reactions using sources like LiAlH4, NaBH4 to reduce carbonyl groups, nitro groups, and more.
3) Dissolving metal reductions using reactive metals like Li, Na in ammonia solution (Birch reduction) to reduce aromatics.
4) Specific reducing agents and conditions are described for reducing different functional groups selectively like carbonyls, nitriles, alkynes and more.
This document summarizes common reduction reactions using lithium aluminium hydride (LiAlH4) and sodium borohydride (NaBH4) as reducing agents. LiAlH4 can reduce carboxylic acids, aldehydes, and ketones, while NaBH4 is only strong enough to reduce aldehydes and ketones. The reductions of aldehydes to alcohols, ketones to secondary alcohols, and carboxylic acids to primary alcohols are presented along with examples and balanced equations. Reduction of nitrobenzene to aniline is also summarized in two steps using tin and hydrochloric acid followed by sodium hydroxide.
The complex metal hydrides are generally salts in which the anions contain hydrides
They typically contain more than one type of metal or metalloid and can be soluble or react with water
General Formula of Complex Metal Hydrides- MxM'yHn
where, M= Alkali metal; M'= Metal/Metalloid
This document discusses the properties of alcohols, phenols, ethers, and thiols. Alcohols contain a hydroxyl group and are polar due to the electronegativity difference between oxygen and hydrogen. They have higher boiling points than hydrocarbons due to hydrogen bonding. Phenols contain a hydroxyl group attached to a benzene ring and are somewhat soluble in water. Ethers have the general formula R-O-R and have polar C-O bonds but do not form hydrogen bonds. Thiols contain a sulfhydryl group and are similar to alcohols but with sulfur replacing oxygen.
This document summarizes various methods of chemical reduction. It discusses heterogeneous catalytic hydrogenation using platinum, palladium, nickel, and copper chromite catalysts. Alkenes are converted to alkanes, and unsaturated functional groups like carbonyls, nitriles, and aromatics can be reduced. Homogenous hydrogenation uses soluble transition metal complexes as catalysts, like rhodium and ruthenium. Rhodium complexes selectively reduce double bonds without affecting other functional groups. Reduction of alkynes, aromatics, aldehydes, ketones, nitriles, oximes and nitro compounds are also summarized. The mechanisms of catalytic and homogenous hydrogenation are provided.
This document provides information about amination by reduction. It discusses various reduction methods used to synthesize amines including metal and acid reduction, metal hydrides, sulfides, and electrolysis. Metal and acid reduction, specifically the Bechamp method using iron and hydrochloric acid, is described in detail. An example process for the production of aniline via the reduction of nitrobenzene is outlined, including reaction details and equipment used. Amines produced by these reductive methods are important intermediates for chemicals, dyes, pharmaceuticals, and other industrial products.
1. Lithium aluminum hydride (LiAlH4) is a strong reducing agent that can reduce a wide range of functional groups like aldehydes, ketones, esters, acids, and nitriles to alcohols. It works by donating hydride ions (H-) that react with electrophilic carbons.
2. Sodium borohydride (NaBH4) is a milder reducing agent that can only reduce aldehydes and ketones to alcohols. It is soluble in alcohol and water, making it advantageous for polar substrates.
3. Diborane (B2H6) adds to carbon-carbon double bonds in a stere
This document discusses various types of reduction reactions including:
1) Catalytic hydrogenation using metals like Pt, Pd, Ni, Ru, Rh to reduce double and triple bonds.
2) Hydride transfer reactions using sources like LiAlH4, NaBH4 to reduce carbonyl groups, nitro groups, and more.
3) Dissolving metal reductions using reactive metals like Li, Na in ammonia solution (Birch reduction) to reduce aromatics.
4) Specific reducing agents and conditions are described for reducing different functional groups selectively like carbonyls, nitriles, alkynes and more.
This document summarizes common reduction reactions using lithium aluminium hydride (LiAlH4) and sodium borohydride (NaBH4) as reducing agents. LiAlH4 can reduce carboxylic acids, aldehydes, and ketones, while NaBH4 is only strong enough to reduce aldehydes and ketones. The reductions of aldehydes to alcohols, ketones to secondary alcohols, and carboxylic acids to primary alcohols are presented along with examples and balanced equations. Reduction of nitrobenzene to aniline is also summarized in two steps using tin and hydrochloric acid followed by sodium hydroxide.
Catalysis by solid bases [recovered] [autosaved]KANUPRIYASINGH19
This document discusses solid base catalysts as a green approach for chemical synthesis. It describes various types of solid bases including hydrotalcites, zeolites, and amines immobilized on silica. Hydrotalcites have basic sites in the interlayer space and can catalyze aldol condensations and ionone synthesis as a replacement for NaOH. Zeolites with exchanged alkali cations or loaded metal oxides also exhibit basic properties and can catalyze reactions like the Knoevenagel condensation. Immobilizing amines and ammonium groups on silica via grafting produces heterogeneous basic catalysts. Solid bases offer advantages over liquid bases like recyclability, easy separation, and generating less waste
I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes different types of reduction reactions. It discusses the mechanism of reduction reactions as the removal of oxygen or addition of hydrogen. It describes two types of catalysts - homogeneous and heterogeneous. It also outlines several specific types of reduction reactions including catalytic hydrogenation, hydride transfer reactions, dissolving metal reactions, replacement of oxygen by hydrogen, reductive coupling, and reduction with cleavage. Key reducing agents mentioned are lithium aluminum hydride, sodium borohydride, and various transition metals.
Lithium aluminium hydride (LAH) is a strong reducing agent that is commonly used to reduce carbonyl groups, esters, amides, nitriles, epoxides, lactones, and haloalkanes/haloarenes. LAH is prepared through the reaction of lithium hydride with aluminum chloride. It is a white solid that reacts violently with water, producing hydrogen gas, so reactions must be performed under anhydrous conditions. The mechanism of LAH involves nucleophilic hydride attack on the carbonyl carbon to form an intermediate tetrahedral structure.
The document discusses Lindlar's catalyst and Adam's catalyst. Lindlar's catalyst consists of palladium deposited on calcium carbonate and poisoned with lead or sulfur. It is used to selectively hydrogenate alkynes to alkenes without full reduction to alkanes. Adam's catalyst, also known as platinum dioxide PtO2•H2O, is used for hydrogenation, hydrogenolysis, dehydrogenation, and oxidation reactions. It hydrogenates alkenes with syn stereochemistry and is commonly used to reduce ketones to alcohols and nitro compounds to amines. Both catalysts provide selective hydrogenation under mild conditions.
This document is a chapter from a general chemistry textbook titled "General Chemistry: Principles and Modern Applications". It focuses on main group elements, specifically metals. The chapter covers Group 1 alkali metals such as lithium, sodium, and potassium. It also discusses Group 2 alkaline earth metals including beryllium, magnesium, calcium, and barium. Additional topics include ions in natural waters that cause hardness, Group 13 metals aluminum gallium and thallium, and Group 14 metals tin and lead.
Definition, Classification, chemical test, properties , uses, Distribution and occurrence, Extraction isolation, chromatography methods of purification,Function of alkaloids.
The H&E stain is the most common stain used in histology. It involves staining tissue samples with hematoxylin, which stains nuclei blue, followed by a counterstain with eosin, which stains cytoplasm and other tissue structures pink. The staining process involves deparaffinization, hydration, hematoxylin staining, differentiation, bluing, eosin counterstaining, dehydration, clearing, and coverslipping. Both automated and manual methods can be used to perform the H&E stain, and quality control measures help ensure consistent, high-quality results.
Hematoxylin and eosin (H&E) staining is the most common histological staining method. Hematoxylin stains cell nuclei blue by combining with oxidized hematin and a mordant like alum. Eosin stains cytoplasm and extracellular substances pink. For H&E staining, tissue sections are stained in hematoxylin, rinsed in acid alcohol to differentiate nuclei, rinsed in water to turn nuclei blue, and then stained in eosin to color non-nuclear structures pink, allowing easy visualization of cell morphology. H&E staining provides essential structural information and is useful for pathology examinations.
The document summarizes hematoxylin and eosin staining. Hematoxylin is extracted from logwood and stains cell nuclei blue-black by binding to DNA and RNA. It requires a mordant like aluminum or iron to bind to tissues. The staining process involves hematoxylin ripening, which can be done naturally or chemically using oxidizing agents. Different hematoxylin formulations use different mordants and oxidation methods. Hematoxylin is then differentiated using an acid to remove excess stain from cytoplasm before bluing and mounting. Common hematoxylin stains discussed include Ehrlich's, Mayer's, Harris', and Gill's.
This document provides an overview of reduction reactions in organic chemistry. It discusses various types of reduction reactions including catalytic hydrogenation, hydride transfer reactions using reagents like LiAlH4 and NaBH4, dissolving metal reductions, and others. Specific metal hydride reductions using boron and aluminum reagents like sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride, and diisobutylaluminum hydride are explained in detail including their mechanisms and selectivity. Diimide reduction is also briefly covered. The document concludes with a bibliography of reference books on organic reaction mechanisms.
The document outlines various chemical tests that can be used to identify alcohols, phenols, aldehydes, and ketones based on their observable reactions. It describes tests such as the Lucas test, reactions with potassium dichromate, bromine water tests, and FeCl3 tests to identify alcohols and phenols. It also covers tests like the 2,4-DNPH test, Tollen's test, Fehling's test, and iodoform test that can be used to detect and distinguish between aldehydes and ketones.
IMPORTANT NAMED REACTIONS in Organic synthesis with Introduction, General Mechanism, and their synthetic application covering more than 20 named reactions in it.
Potassium permanganate, potassium dichromate – one of the excellent tools of ...Istiqur Rahman
This document discusses pharmaceutical analysis and different types of titration methods. It focuses on redox titration and provides details about common oxidizing agents used - potassium permanganate and potassium dichromate. Potassium permanganate is highlighted as a stronger oxidizing agent compared to potassium dichromate due to its higher oxidation state of +7 and ability to oxidize a wider range of functional groups. Both oxidizing agents are compared in terms of their toxicity, with potassium dichromate noted as being more hazardous to health.
1. Hematoxylin and eosin staining is the most widely used staining technique in histopathology. Hematoxylin stains nuclei blue/black while eosin stains cytoplasm and extracellular components pink.
2. Hematoxylin requires oxidation to produce hematein, the active dye, and uses a mordant like aluminum or iron salts to bind it to tissue. Eosin is a xanthine dye that stains cytoplasm and extracellular components red.
3. The basic steps of hematoxylin and eosin staining involve staining with hematoxylin, differentiating, bluing, staining with eosin, dehydration and mounting. Proper timing is needed for each step to achieve optimal
B.phram
Semester .4
Subject : Organic chemistry - III
Use as reference and also usable for examination prearation.
gtu afflitited phramacy college's student may using this ppt.
This presentation will help students to understand the various topics related with halogen compounds in a very short time.it also help teachers during the recapitulation of the chapter content.it will also help students to revise the content in short time especially by those students who r preparing for various competitive exams after class 12th.
This document summarizes a seminar on dissolving metals and Birch reduction presented by Miss. Neha Milind Dhansekhar. The seminar covered: (1) Reduction using metals like Zn, Li, Na, and Mg under neutral and acidic conditions; (2) Birch reduction using Li/Na in liquid ammonia to reduce aromatics and acetylene; and (3) Specific examples of reductions like sodium alcohol reducing ketones to alcohols and Birch reduction reducing aromatic rings.
- Hematoxylin and eosin (H&E) staining is the most widely used staining technique in histopathology. Hematoxylin stains cell nuclei blue-black, while eosin stains cytoplasm and other tissues shades of pink-red.
- Hematoxylin is extracted from the logwood tree and must be oxidized to hematin to function as a stain. It is used with a mordant like aluminum or iron salts to bind to cell nuclei. Alum hematoxylins are the most common and produce red nuclei that are "blued" after staining.
- Different hematoxylin solutions exist based on the mordant used, including alum, iron,
This document contains numerical data across 8 rows listing numbers ranging from 17,694,369 to 20,889,933 in the first column and numbers ranging from 9 to 18 in the second column. The data appears to be listing some values alongside other corresponding values but does not provide enough context to determine what specifically is being counted or measured.
Libro day ops-2005-como-redactar-articulosmtapizque
Este documento presenta las instrucciones para escribir y publicar trabajos científicos. Explica que la publicación de investigaciones es fundamental para la ciencia y que los científicos son juzgados principalmente por sus publicaciones. Además, destaca que comunicar claramente los resultados es esencial ya que permite que otros verifiquen los hallazgos y contribuyan al conocimiento científico. Finalmente, enfatiza que redactar de manera efectiva es importante no solo para difundir los descubrimientos, sino también para el progreso de la ci
Catalysis by solid bases [recovered] [autosaved]KANUPRIYASINGH19
This document discusses solid base catalysts as a green approach for chemical synthesis. It describes various types of solid bases including hydrotalcites, zeolites, and amines immobilized on silica. Hydrotalcites have basic sites in the interlayer space and can catalyze aldol condensations and ionone synthesis as a replacement for NaOH. Zeolites with exchanged alkali cations or loaded metal oxides also exhibit basic properties and can catalyze reactions like the Knoevenagel condensation. Immobilizing amines and ammonium groups on silica via grafting produces heterogeneous basic catalysts. Solid bases offer advantages over liquid bases like recyclability, easy separation, and generating less waste
I hope You all like it. I hope It is very beneficial for you all. I really thought that you all get enough knowledge from this presentation. This presentation is about materials and their classifications. After you read this presentation you knowledge is not as before.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document summarizes different types of reduction reactions. It discusses the mechanism of reduction reactions as the removal of oxygen or addition of hydrogen. It describes two types of catalysts - homogeneous and heterogeneous. It also outlines several specific types of reduction reactions including catalytic hydrogenation, hydride transfer reactions, dissolving metal reactions, replacement of oxygen by hydrogen, reductive coupling, and reduction with cleavage. Key reducing agents mentioned are lithium aluminum hydride, sodium borohydride, and various transition metals.
Lithium aluminium hydride (LAH) is a strong reducing agent that is commonly used to reduce carbonyl groups, esters, amides, nitriles, epoxides, lactones, and haloalkanes/haloarenes. LAH is prepared through the reaction of lithium hydride with aluminum chloride. It is a white solid that reacts violently with water, producing hydrogen gas, so reactions must be performed under anhydrous conditions. The mechanism of LAH involves nucleophilic hydride attack on the carbonyl carbon to form an intermediate tetrahedral structure.
The document discusses Lindlar's catalyst and Adam's catalyst. Lindlar's catalyst consists of palladium deposited on calcium carbonate and poisoned with lead or sulfur. It is used to selectively hydrogenate alkynes to alkenes without full reduction to alkanes. Adam's catalyst, also known as platinum dioxide PtO2•H2O, is used for hydrogenation, hydrogenolysis, dehydrogenation, and oxidation reactions. It hydrogenates alkenes with syn stereochemistry and is commonly used to reduce ketones to alcohols and nitro compounds to amines. Both catalysts provide selective hydrogenation under mild conditions.
This document is a chapter from a general chemistry textbook titled "General Chemistry: Principles and Modern Applications". It focuses on main group elements, specifically metals. The chapter covers Group 1 alkali metals such as lithium, sodium, and potassium. It also discusses Group 2 alkaline earth metals including beryllium, magnesium, calcium, and barium. Additional topics include ions in natural waters that cause hardness, Group 13 metals aluminum gallium and thallium, and Group 14 metals tin and lead.
Definition, Classification, chemical test, properties , uses, Distribution and occurrence, Extraction isolation, chromatography methods of purification,Function of alkaloids.
The H&E stain is the most common stain used in histology. It involves staining tissue samples with hematoxylin, which stains nuclei blue, followed by a counterstain with eosin, which stains cytoplasm and other tissue structures pink. The staining process involves deparaffinization, hydration, hematoxylin staining, differentiation, bluing, eosin counterstaining, dehydration, clearing, and coverslipping. Both automated and manual methods can be used to perform the H&E stain, and quality control measures help ensure consistent, high-quality results.
Hematoxylin and eosin (H&E) staining is the most common histological staining method. Hematoxylin stains cell nuclei blue by combining with oxidized hematin and a mordant like alum. Eosin stains cytoplasm and extracellular substances pink. For H&E staining, tissue sections are stained in hematoxylin, rinsed in acid alcohol to differentiate nuclei, rinsed in water to turn nuclei blue, and then stained in eosin to color non-nuclear structures pink, allowing easy visualization of cell morphology. H&E staining provides essential structural information and is useful for pathology examinations.
The document summarizes hematoxylin and eosin staining. Hematoxylin is extracted from logwood and stains cell nuclei blue-black by binding to DNA and RNA. It requires a mordant like aluminum or iron to bind to tissues. The staining process involves hematoxylin ripening, which can be done naturally or chemically using oxidizing agents. Different hematoxylin formulations use different mordants and oxidation methods. Hematoxylin is then differentiated using an acid to remove excess stain from cytoplasm before bluing and mounting. Common hematoxylin stains discussed include Ehrlich's, Mayer's, Harris', and Gill's.
This document provides an overview of reduction reactions in organic chemistry. It discusses various types of reduction reactions including catalytic hydrogenation, hydride transfer reactions using reagents like LiAlH4 and NaBH4, dissolving metal reductions, and others. Specific metal hydride reductions using boron and aluminum reagents like sodium borohydride, sodium cyanoborohydride, lithium aluminum hydride, and diisobutylaluminum hydride are explained in detail including their mechanisms and selectivity. Diimide reduction is also briefly covered. The document concludes with a bibliography of reference books on organic reaction mechanisms.
The document outlines various chemical tests that can be used to identify alcohols, phenols, aldehydes, and ketones based on their observable reactions. It describes tests such as the Lucas test, reactions with potassium dichromate, bromine water tests, and FeCl3 tests to identify alcohols and phenols. It also covers tests like the 2,4-DNPH test, Tollen's test, Fehling's test, and iodoform test that can be used to detect and distinguish between aldehydes and ketones.
IMPORTANT NAMED REACTIONS in Organic synthesis with Introduction, General Mechanism, and their synthetic application covering more than 20 named reactions in it.
Potassium permanganate, potassium dichromate – one of the excellent tools of ...Istiqur Rahman
This document discusses pharmaceutical analysis and different types of titration methods. It focuses on redox titration and provides details about common oxidizing agents used - potassium permanganate and potassium dichromate. Potassium permanganate is highlighted as a stronger oxidizing agent compared to potassium dichromate due to its higher oxidation state of +7 and ability to oxidize a wider range of functional groups. Both oxidizing agents are compared in terms of their toxicity, with potassium dichromate noted as being more hazardous to health.
1. Hematoxylin and eosin staining is the most widely used staining technique in histopathology. Hematoxylin stains nuclei blue/black while eosin stains cytoplasm and extracellular components pink.
2. Hematoxylin requires oxidation to produce hematein, the active dye, and uses a mordant like aluminum or iron salts to bind it to tissue. Eosin is a xanthine dye that stains cytoplasm and extracellular components red.
3. The basic steps of hematoxylin and eosin staining involve staining with hematoxylin, differentiating, bluing, staining with eosin, dehydration and mounting. Proper timing is needed for each step to achieve optimal
B.phram
Semester .4
Subject : Organic chemistry - III
Use as reference and also usable for examination prearation.
gtu afflitited phramacy college's student may using this ppt.
This presentation will help students to understand the various topics related with halogen compounds in a very short time.it also help teachers during the recapitulation of the chapter content.it will also help students to revise the content in short time especially by those students who r preparing for various competitive exams after class 12th.
This document summarizes a seminar on dissolving metals and Birch reduction presented by Miss. Neha Milind Dhansekhar. The seminar covered: (1) Reduction using metals like Zn, Li, Na, and Mg under neutral and acidic conditions; (2) Birch reduction using Li/Na in liquid ammonia to reduce aromatics and acetylene; and (3) Specific examples of reductions like sodium alcohol reducing ketones to alcohols and Birch reduction reducing aromatic rings.
- Hematoxylin and eosin (H&E) staining is the most widely used staining technique in histopathology. Hematoxylin stains cell nuclei blue-black, while eosin stains cytoplasm and other tissues shades of pink-red.
- Hematoxylin is extracted from the logwood tree and must be oxidized to hematin to function as a stain. It is used with a mordant like aluminum or iron salts to bind to cell nuclei. Alum hematoxylins are the most common and produce red nuclei that are "blued" after staining.
- Different hematoxylin solutions exist based on the mordant used, including alum, iron,
This document contains numerical data across 8 rows listing numbers ranging from 17,694,369 to 20,889,933 in the first column and numbers ranging from 9 to 18 in the second column. The data appears to be listing some values alongside other corresponding values but does not provide enough context to determine what specifically is being counted or measured.
Libro day ops-2005-como-redactar-articulosmtapizque
Este documento presenta las instrucciones para escribir y publicar trabajos científicos. Explica que la publicación de investigaciones es fundamental para la ciencia y que los científicos son juzgados principalmente por sus publicaciones. Además, destaca que comunicar claramente los resultados es esencial ya que permite que otros verifiquen los hallazgos y contribuyan al conocimiento científico. Finalmente, enfatiza que redactar de manera efectiva es importante no solo para difundir los descubrimientos, sino también para el progreso de la ci
(1) El documento describe un experimento de laboratorio para sintetizar acetanilida a partir de la reacción de anilina con anhídrido acético. (2) El procedimiento involucra varios pasos como filtración, cristalización y decoloración para purificar el producto final. (3) El documento también discute el mecanismo de reacción, las precauciones de seguridad y los reactivos y materiales necesarios.
Adsorptive stripping differential pulse voltammetry determination of rivastig...Pramod Kalambate
The study of graphene nanosheet (GNS)–gold nanoparticle (AuNP)–carbon paste electrode (GNS–AuNP–CPE) as
an electrochemical sensor for the determination of rivastigmine (RIV) in pharmaceuticals formulations, blood
serum, and urine samples is presented. The GNS–AuNP composite is prepared by in situ simultaneous reduction
of graphene oxide and chloroauric acid using sodiumborohydride as a reducing agent. The GNS–AuNP composite
was characterized by X-ray diffraction, UV–Vis spectroscopy, and scanning electron microscopy. Electrochemical
characterization of the GNS–AuNP–CPE electrode surfacewas carried out by cyclic voltammetry, electrochemical
impedance spectroscopy, chronocoulometry, and adsorptive stripping differential pulse voltammetry. This study
shows that oxidation of rivastigmine is facilitated at the GNS–AuNP–CPE electrode and remarkably increase in
current compared to the bare electrode due to enhanced adsorption of the former on electrode surface. Under
the optimized conditions, the peak current (Ip) is found to be proportional to the RIV concentration in the
range of 2.0 × 10–7–6.0 × 10−4 M with a detection limit of 5.3 × 10−8 M. The proposed sensor shows a very
high level of sensitivity, selectivity, and a very good reproducibility for RIV determination. A good recovery
level obtained for real samples suggests practical utility of the GNS–AuNP–CPE as an effective and reliable electrochemical
sensor for RIV detection.
The document discusses the use of gold nanoparticles for cancer detection and treatment. It describes how gold nanoparticles can be functionalized with antibodies to detect specific cancer types by binding to protein markers on cancer cells. Laser-activated gold nanoparticles may also be used to destroy cancer cells through localized heating. The document also mentions potential applications for targeted drug delivery and angiogenesis inhibition. Overall, the document outlines how the optical and structural properties of gold nanoparticles can be exploited for cancer diagnosis and therapy.
This document discusses various methods for synthesizing silver nanoparticles (Ag NPs). It covers physical approaches like evaporation-condensation and laser ablation. It then discusses several chemical approaches for reduction of silver ions to produce Ag NPs, including reduction by tri-sodium citrate, sodium borohydride, UV irradiation, gamma irradiation, laser irradiation, microwave irradiation, sonochemical reduction, and electrochemical methods. It notes the advantages of these chemical synthesis techniques and how stabilizing agents prevent agglomeration of the nanoparticles.
This document discusses the use of gold nanoparticles for the treatment of cancer. It begins with an introduction to cancer and the side effects of traditional chemotherapy and radiation treatments. It then discusses how nanotechnology can be used to develop targeted drug delivery systems using gold nanoparticles. The document outlines the properties of gold nanoparticles that make them suitable for photothermal therapy applications for cancer treatment, including their ability to absorb light and generate heat. It also discusses the different types of gold nanoparticles, methods for synthesizing and characterizing them, and their potential applications and progress in cancer treatment.
LIST OF AMERICAN JEWISH POLITICIANS - WIKIPEDIA As Of 07/17/16VogelDenise
17 USC § 107 (LIMITATIONS On EXCLUSIVE Rights - FAIR USE)
This is a listing of some of the Jewish American Politicians listed in Wikipedia as of 07/17/16 – i.e. a SELECTIVE Listing it appears!
020915 PUBLIC RELEASE EEOC CHARGE AGAINST 1ST HERITAGE CREDIT (Arabic)VogelDenise
09/02/15 بيان علني من قبل EEOC ضد حقوق المساهمين CREDIT 1ST - نددت الولايات المتحدة الأمريكية الأعمال الإرهابية العنصرية منهجية - مشاهدة ورؤية كيف أن الرئيس باراك أوباما، كونغرس الولايات المتحدة، محاميه دونلسون Bearman كالدويل بيكر وبيركوفيتش معا مع وأوروبا الغربية حلفاء يهودية / / الخاص بك يعمل للتغطية على جرائمهم والمظالم المدنية!
سمعت أنهم من ويلي لينش؟ هل رأيت ويلي لينش في الممارسة العملية؟
http://www.slideshare.net/VogelDenise/barack-obama-understanding-willie-lynch-arabic-44720526
This document discusses copyright and how to properly use copyrighted material. It explains that when you create an original work, it is automatically copyrighted. To use copyrighted material, you need permission from the copyright owner. The summary outlines the process of finding out who owns the copyright, writing to request permission, and properly citing the source.
020915 PUBLIC RELEASE EEOC CHARGE AGAINST 1ST HERITAGE CREDIT (German)VogelDenise
www.vogeldenisenewsome.net
SAHEN SIE WILLIE LYNCH KOMMT ZU IHREM LAND? Frag-Präsident Barack Obama, er und seine JÜDISCHE Counterparts sind sehr vertraut mit WILLIE LYNCH! Warum glauben Sie, Barack Obama und Michelle Obama wurden in den VEREINIGTEN STAATEN WHITE HOUSE setzen? Zu schieben die WILLIE LYNCH AGENDA!
This document provides an overview of public safety programs at Central Piedmont Community College, including quotes about honor and heroism. It thanks various individuals involved in criminal justice and fire protection programs. The document encourages the reader to learn more through a public safety web tour featuring pages about criminal justice, fire protection technology, forensic programs, and law enforcement training available at the college.
This document discusses solutions and provides information on:
- The three types of solutions - solid, liquid, and gaseous solutions depending on whether the solvent is solid, liquid, or gas.
- Factors that affect the rate of solubility such as particle size, agitation, and temperature.
- Factors that affect the solubility of a solute such as temperature, molecular structure, effects of other substances, and pH.
- Examples of oral solutions from different categories such as antidepressants, bronchodilators, antipsychotics, and vitamins.
- Characteristics and preparation methods of aqueous solutions and aromatic waters.
This experiment involves a crossed aldol condensation reaction between benzaldehyde and acetone to form dibenzalacetone. The reaction follows an enolate mechanism under basic conditions using sodium hydroxide as the base. The product is recrystallized from ethanol and its melting point, IR spectrum, and predicted 13C-NMR spectrum are analyzed to identify and characterize dibenzalacetone.
This document provides background information on the oxidation of cyclohexanol to cyclohexanone. It discusses the commercial importance of this reaction and how cyclohexanone is used to produce nylon. It then outlines safety considerations and provides definitions and explanations of key concepts like oxidation, reduction, and oxidizing/reducing agents. Finally, it gives the balanced reaction equation and describes the mechanism and solubility differences that allow the product to be isolated.
The document summarizes key information about alcohols, phenols, thiols, and ethers from Chapter 12. It discusses the structures, properties, and reactions of these functional groups. Alcohols contain a hydroxyl group (-OH) and are polar due to hydrogen bonding. Their solubility decreases with increasing carbon chain length. Alcohols can be prepared by hydration of alkenes or hydrogenation of carbonyl groups. They undergo oxidation, dehydration, and substitution reactions. Phenols contain a hydroxyl group attached to an aromatic ring. Ethers have an oxygen atom bonded to two alkyl groups instead of a hydroxyl group and alkyl group. Thiols are analogous to alco
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1. Stock solution concentration: 100 μg/ml
2. Dilute 1 ml stock solution to 10 ml. This gives 10 μg/ml.
Initial volume: 1 ml Final volume: 10 ml Concentration: 10 μg/ml
3. Dilute 2 ml of the above solution to 10 ml. This gives 12 μg/ml
Initial volume: 2 ml Final volume: 10 ml Concentration: 12 μg/ml
4. Dilute 3 ml of the above solution to 10 ml. This gives 13.5 μg/ml
Initial volume: 3 ml Final volume: 10 ml Concentration: 13.5 μg/
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Reduccion de vainilla na bh4 quim verde
1. Sodium Borohydride Reduction of Vanillin: A Low Solvent
Synthesis of Vanillyl Alcohol1,2
Carl S. Lecher, Marian College, Indianapolis, IN, clecher@marian.edu
Chemical Concepts
Nucleophilic addition to carbonyl compounds, reduction reactions, preparation of alcohols
Laboratory Techniques
Vacuum filtration, crystal formation, melting point determination, IR spectroscopy
Green Chemistry Principles
Use of renewable feedstock, benign solvents, reduced solvent use, benign reactant and product
Estimated Lab Time
1.5 hours
Scenario
You have recently been hired by Lecher Consulting Enterprise, a top notched chemical consulting firm
which specializes in environmentally benign chemical techniques and procedures. You have been assigned
to work on the following:
Oscar de Groucho, the president of Grouch Loves Trash Waste Disposal Company, has recently won the
bid to dispose of lignin and other paper production by-products from the local paper mill. Living by the
motto ‘One man’s trash is another man’s treasure,’ Oscar has sought the expertise of Lecher Consulting
Enterprises. Chemical treatment of lignin yields large quantities of vanillin, a white powder responsible for
the sent of vanilla. Oscar is looking for new synthetic applications for the vanillin that he will be
producing.
Figure 1
O
H OH
HO HO
O O
4-hydroxy-3-methoxybenzaldehyde 4-hydroxy-3-methoxybenzyl alcohol
a.k.a. vanillin a.k.a. vanillyl alcohol
m.p. 81-83oC m.p. 110-117oC
Vanillyl alcohol, which is made by the reduction of vanillin, shows promise as a renewable starting
material for the synthesis of biologically active molecules and flavoring ingredients. Two insect species,
the African sugar-cane borer moth3 and the Leaffooted pine seed bug,4 utilize vanillyl alcohol in its
chemical communication system.
1
Carl S. Lecher, Marian College, Indianapolis, IN, (317) 955 6005, clecher@marian.edu.
2
This laboratory procedure was developed with the assistance of Brandie Davis, B.S. Biology, Marian College, 2006.
3
Burger, B.V., Nell, A.E., Smit, D., Spies, H.S.C., Mackenroth, W.M., Groche, D., and Atkinson, P.R. J. Chem. Ecol.
1993, 19, 2255-2277.
4
Aldrich, J.R., Blum, M.S., and Fales, H.M. J. Chem. Ecol. 1979, 5, 53-62.
Sodium Borohydride Reduction of Vanillin – GEMs 2007 1
2. Background
Vanillin (4-hydroxy-3-methoxybenzaldehyde), a pleasant smelling aromatic compound, occurs naturally in
the pods of the vanilla plant (Vanilla planifolia), which is native to Mexico.5 Although the finest vanilla
flavoring is still obtained from natural vanilla, synthetic vanillin is far less costly. It is used widely as a
flavoring additive for beverages, cooking, and as an aromatic additive for candles, incense, potpourri,
fragrances, perfumes, and air fresheners. It is also used as a starting material for the synthesis of such
drugs as L-dopa, which is used for treating Parkinson's disease.
At one time synthetic vanillin was made mostly from isoeugenol, a naturally occurring and widely used
perfume ingredient. Most vanillin is now synthesized using lignin derived from wood pulp. Lignin is a
complex polymer that gives rigidity to trees and other woody plants. After cellulose, lignin is the second
most abundant organic material on earth.
Reduction Reactions
In chemistry, reduction refers to the gain of electrons. This is usually manifested through the gain of
hydrogen atoms or a loss of oxygen atoms, or both. For example, a carbonyl compound is reduced to an
alcohol when its carbonyl group gains a hydride and a proton.
Reducing Agents
When lithium aluminum hydride (LiAlH4) was introduced as a reducing agent in the late 1940s, it brought
about a revolution in the preparation of alcohols by reduction. At that time, the most popular reducing
agents for carbonyl compounds were sodium metal and gaseous hydrogen under pressure. The greater
simplicity and convenience of hydride reduction soon made it the preferred method for a broad spectrum of
chemical reductions. Lithium aluminum hydride is a powerful reducing agent whose high reactivity is a
disadvantage in some applications. Because it reacts violently with water, alcohols, and phenols to release
hydrogen gas, it can be used only in aprotic solvents, such as ether under strictly anhydrous conditions.
By contrast, sodium borohydride (NaBH4) is a much milder reducing agent that is comparatively safe to
handle in its solid form. Unlike lithium aluminum hydride, it can be used even in aqueous or alcoholic
solutions.
Reaction Stoichiometry
The overall stoichiometry of the sodium borohydride reduction of vanillin is given by the following
equation:
O
H + NaBH + 4 H O OH
4 4 2 4 + H3BO3 + NaOH
HO HO
O O
Scheme 1. Reaction Stoichiometry
In practice, it is best to use a 50-100% excess of sodium borohydride to compensate for any that reacts with
the solvent or decomposes from other causes. Since the reaction is first order in sodium borohydride (as
well as the carbonyl compound), using an excess will also increase the reaction rate.
5
Vanillin is actually not found in the fresh vanilla bean, but is formed by the enzymatic breakdown of a glucoside
during the curing process.
Sodium Borohydride Reduction of Vanillin – GEMs 2007 2
3. Reaction Solvents
Sodium borohydride reductions are usually carried out in a dilute (~1 M) aqueous NaOH solution or an
alcohol. The reagent is not stable at low pH, and even in a neutral aqueous solution it decomposes to the
extent of about 4.5% per hour at 25°C. Acidic functional groups, such as COOH and the OH group of a
phenol, may cause rapid decomposition of sodium borohydride. Sodium borohydride reacts slowly with
alcohols, but ethanol and methanol are usually suitable solvents when there are no acidic functional groups
and the reaction time is no more than 30 minutes at 25°C.
Reaction Conditions
In most reactions with sodium borohydride, the aldehyde or ketone is dissolved in the reaction solvent and
a solution of sodium borohydride is added, with external cooling if necessary, at a rate slow enough to keep
the reaction temperature below 25°C. Higher temperatures may decompose the hydride, and adding the
carbonyl compound to the alkaline sodium borohydride solution may cause side reactions of base-sensitive
substrates. The amount of solvent is not crucial, but enough should be used to completely dissolve the
reactants
The time required to complete the reaction depends on the reaction temperature and the reactivity of the
substrate. Most reactions of aldehydes and aliphatic ketones are complete in 30 minutes at room
temperature.
Workup of the Reaction Mixture
After the reaction is complete, the excess sodium borohydride is decomposed by acidifying the reaction
mixture to pH 6 or below (slowly and while stirring) using aqueous HCl. Hydrogen gas is evolved during
this process as the excess sodium borohydride decomposes.
Depending on the properties of the product and the reaction solvent used, the product can be separated from
the reaction mixture by filtration, extraction, or partial evaporation of the solvent followed by extraction.
Purification
The product can be purified, if needed, by any appropriate
method based on its physical state and properties. Vanillyl
alcohol is soluble in hot water, hot and cold ethanol, and hot
and cold ether. It is relatively insoluble in cold water and it
tends to form supersaturated solutions in water.
separatory
In the lab funnel
It is your task to carry of the reduction of vanillin, and to ring stand
analyze the procedure gap
25 mL round
bottom flask
ice bath
8
7
6 5
4
3 8
7
6 5
4
3
stir plate
9 2 9 2
10 1 11 1
Figure 2. Apparatus
Sodium Borohydride Reduction of Vanillin – GEMs 2007 3
4. Scheme 2. Reaction Scheme
O
OH
H 1. NaBH4
HO
HO 2. H3O+ workup
O
O
4-hydroxy-3-methoxybenzaldehyde 4-hydroxy-3-methoxybenzyl alcohol
a.k.a. vanillin a.k.a. vanillyl alcohol
m.p. 81-83oC m.p. 110-117oC
C8H8O3 = 152.15 C8H10O3 = 154.16
Reaction Table
Formula
Name Weight density eq mmol wt / vol
vanillin 152.15 -- 1.00 17.1 2.60 g
NaBH4 (3.42 M in 1.0 M NaOH) 37.83 -- 1.00 17.1 5.0 mL
*note: use YOUR weight and YOUR volume for your reaction table
Safety Precautions
Hydrochloric acid: Hydrochloric acid is corrosive and a chemical burn hazard. Avoid contact. If contact is
made with the skin, wash the affected area with cold water for 15 minutes.
NaBH4 solution: NaBH4 solution is caustic and will decompose violently with acid. Handle with care.
Experimental Procedure
Synthesis of Vanillyl Alcohol
1. Weigh between 2.5 and 2.6 g of vanillin into a 50 mL beaker. Record the weight directly into your
notebook to the maximum accuracy of the balance.
2. Fill out your reaction table by calculating the mmol and equivalents of reagents used based on
YOUR mass of vanillin.
3. Transfer the vanillin to a 25 mL round bottom flask using a solid addition funnel. Rinse your
beaker and funnel with 5.0 mL of ethanol.6 This ethanol will be the solvent for the reaction.
4. Add stir bar and dissolve the vanillin. If the vanillin does not dissolve, gently warm the flask with
your hand.
5. Read thoroughly before starting this step! Set up the reaction as follows:
a. Add 5.0 mL of NaBH4 solution to a dropping funnel.
b. Clamp the 25 mL round bottom flask in an ice bath as depicted in Figure 2, and immediately
procedure to the next step.
6
Safety note – As a general safety rule, solutes should be added to solvents. The resulting solution should go from
dilute to more concentrated. This is because the solvation process for some compounds can be violently exothermic.
Sodium Borohydride Reduction of Vanillin – GEMs 2007 4
5. c. To the 25 mL round bottom flask, add the NaBH4 solution DROPWISE with stirring over a
period of 10 minutes. Add the first mL especially slow, as a large amount of heat is evolved.
i. You may monitor the temperature of the reaction. If so, keep the reaction temperature
below 25°C.
d. Note any observations.
6. After addition of NaBH4 solution is complete, remove the ice bath. Stir the reaction at room
temperature for 5 minutes to ensure that the reaction has gone to completion.
7. Return the ice bath to the apparatus. Add 6 M HCl DROPWISE with stirring until H2 gas is no
longer evolved. Check the pH to verify that the solution is now acidic.
8. Continue to cool with stirring in the ice bath for 10 minutes. A precipitate will form.
Separation
9. Collect the solid by vacuum filtration. Use small portions (~1 mL) of ice-cold DI water to aid
the transfer of the solid into the filter funnel and to wash the product. With the vacuum
applied, allow the solid to dry on the vacuum for about two minutes.
10. Air dry product to a constant mass in the fume hood for at least 24 hours. (Do NOT oven dry.)
11. The filtrate may be disposed of via the sink with copious amounts of water.
12. Weigh your dried product. Make sure to account for the weight of the filter paper.
Characterization and Calculations
13. Determine the theoretical yield and percent yield for the reaction.
14. Determine the melting point of your substance using a Mel-Temp apparatus.
15. Generate an IR Spectrum for your product. Record important signals in the data section of your
notebook.
16. Confirm the identity of your product.
Disposal
17. When you are satisfied with your data and calculations, place your product in the container labeled
VANILLYL ALCOHOL. The instructor will save this compound for future use.
Sodium Borohydride Reduction of Vanillin – GEMs 2007 5
6. Assignment
In addition to the lab notebook, answer the following questions:
1. The scenario states that vanillin and vanillyl alcohol are renewable starting materials. What is the
difference between renewable and non-renewable resources? Which would be considered to be
greener?
2. Based on the reaction stoichiometry highlighted on page 2, what is the molar ratio between vanillin and
NaBH4?
3. Based your observations during the addition of the NaBH4 solution to the vanillin, and your
understanding of pKas, predict why excess NaBH4 solution is required.
4. Draw the mechanism for the reduction of vanillin. Be sure to account for the generation of H2.
5. What purification technique would be the most appropriate for the purification of vanillyl alcohol?
Explain your rationale.
6. Obtain a 1H NMR spectrum for vanillyl alcohol from your favorite spectral database. Attach this
spectrum and assign the major peaks.
7. Calculate your theoretical yield and percent yield for the reaction.
8. Does your percent yield make sense? If your percent yield is more that 100% or less than 65%,
describe potential reasons for your yield.
9. Calculate the atom economy for the reaction. For the reagents, consider only the mass MW of the
vanillin and sodium borohydride.
Atom economy = (MW desired product / combined MW of all reagents) x 100%
10. Would you consider this reaction to be atom efficient? Justify your answer.
11. Calculate the effective mass yield for the reaction. For NaBH4, be sure to use the mass of the NaBH4,
not the mass of the NaBH4 solution. Ignore the mass of the reagents used for the workup.
Effective mass yield = (mass of desired product obtained / combined mass of all reagents used) x 100%
12. Identify the possible components of the aqueous filtrate. Is it appropriate to disposed of the filtrate via
the drain? Explain your rationale.
13. What is the solvent for this reaction? Is this a green solvent? How does the absence of traditional
solvents improve the greenness of the reaction?
14. How is the product isolated from the reaction mixture? How does this technique minimize the need for
additional solvents?
15. Does the reaction need to be performed with the protection of a fume hood? How doe this effect the
overall safety of the experiment?
Sodium Borohydride Reduction of Vanillin – GEMs 2007 6
7. 16. Essay: Green Chemistry looks to eliminate both the use of hazardous reagents and the generation of
hazardous products. Green chemistry minimizes environmental impact while maximizing safety.
Evaluate the procedure, in its totality, for greenness.
a. Describe at least 4 aspects of the procedure that contribute to its greenness (you may use
those previously mentioned).
b. Suggest at least two ways to improve the procedure.
Requirements:
Please type explanations. Work calculations by hand. Show all work.
Due:
Sodium Borohydride Reduction of Vanillin – GEMs 2007 7
8. Result Submission Form
Lab Title: Sodium Borohydride Reduction of Vanillin: A Low Solvent Synthesis of Vanillyl Alcohol
Name: ______________________________________________
Semester and Year: _________________________________
Reaction Scheme:
O
OH
H 1. NaBH4
HO
HO 2. H3O+ workup
O
O
Your Reaction Table
Formula
Name density eq mmol wt / vol
Weight
vanillin 152.15 --
NaBH4 37.83 --
other reagents not needed in this table
Your Results
Mass Product
Theoretical Yield
% Yield
Melting point range
other values not needed in this table
Explain any reasons why your yield would be lower than expected:
Make at least 1 suggestion for improving the lab:
Sodium Borohydride Reduction of Vanillin – GEMs 2007 8