The reduction of cinnamaldehyde by lithium aluminium hydride lah was reported in a classic series of experiments, dating from 19478. Ac271270000, ac271270100, ac271270250, ac27127 synonyms. Sigmaaldrich offers a number of lithium aluminum hydride products. Lithium aluminum hydride lah is an odorless solid that reacts violently with water, acids and oxygenated compounds. For example, it is used in the conversion of esters, carboxylic acids, acyl chlorides, aldehydes and ketones into their corresponding alcohols. Materials and methods six lithium metal hydrides were investigated, along with lithium, aluminum, and highdensity polyethylene hdpe. Used together with titanium tetrachloride, aluminium hydride can. Firstaid measures general advice if symptoms persist, call a physician. Lithium aluminum hydride supplier distributor cas 16853853.
Ph3snh is triphenyl tin hydride, this is a reagent which will have very different chemistry to sodium borohydride and lithium aluminium hydride. A campus laboratory fire involving lithium aluminum hydride. The reaction was first introduced into the organic chemistry laboratories here at imperial college decades ago, vanished for a short period, and has recently been reintroduced again. It also is used to produce lithium aluminum hydride lialh4, which quickly. Solid state nmr studies of the aluminum hydride phases abstract. Material safety data sheet section 1 lithium aluminium hydride 1 chemical product and company identification msds name. Lithium aluminum hydride as a reducing agent student doctor. So youve probably heard that lialh4 lithium aluminium hydride is stronger than nabh4 sodium borohydride in class. I know that tributyl tin hydride is commonly used as a radical reducing agent. Structure, properties, spectra, suppliers and links for. The stereochemistry of hydride reductions by william g. Solid state nmr studies of the aluminum hydride phases. Lithium aluminum hydride is a remarkably powerful reducing agent.
This alkali metal hydride is a colorless solid, although commercial samples are grey. This material can be purified by recrystallization from diethyl ether. Lithium aluminium hydride, commonly abbreviated to lah, is an inorganic compound with the chemical formula lialh4. American elements offers a broad range of products for hydrogen storage research, advanced fuel cells and battery applications. Noyce received november 22, 1955 it has been shown that reductions of alkylcyclohexanones with lithium aluminum hydride, sodium borohydride and alumi num isopropoxide lead to increasing proportions of the axial unstable isomer. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. Lithium aluminum hydride lialh4 is the stronger common carbonyl reducing agent. Lialh 4 can reduce aldehydes to primary alcohols, ketones to secondary alcohols, carboxylic acids and esters to primary. Characteristic of a saltlike ionic hydride, it has a high melting point, and it is not soluble but reactive with all organic and protic solvents. Lithium hydride is an inorganic compound with the formula li h. Supported by a grant from the national science foundation. The number of electrons in each of lithium s shells is 2, 1 and its electron configuration is he 2s 1. Lithium aluminum hydride, lithium aluminum hydride supplier, lithium aluminum hydride distributor, cas 16853853, lithium aluminum hydride manufacturer, lithium aluminum hydride wholesale.
Mar 24, 1998 a process for the preparation of lithium aluminum hydride in an ethereal solvent via the metathesis of sodium aluminum hydride and lithium chloride in a one direct step reaction comprising heating together sodium aluminum hydride and lithium chloride in an ethereal solvent at a temperature of 25 c. Finally, reduction of the amide moiety using alane generated in situ from the reaction of lithium aluminum hydride and aluminum trichloride, and subsequent deprotection of the ketone with migration of the c c bond, gave 3demethoxyerythratidinone 80, in seven steps starting from the cyclohexadione monoethylene ketal 74 in an unoptimized 10%. Sep 24, 2014 so youve probably heard that lialh4 lithium aluminium hydride is stronger than nabh4 sodium borohydride in class. Lithium aluminium hydride precautionary statements p223 do not allow contact with water. Hydrogen transmissionstorage with metal hydrideorganic. React violently on contact with many oxidizing agents. It was discovered by finholt, bond and schlesinger in 1947. Eye contact immediate medical attention is required. Firstaid measures general advice immediate medical attention is required. Lithium aluminum hydride lialh 4, formed by the reaction of aluminum chloride with lithium hydride, is widely used in organic chemistrye. The lithium metal hydrides in this study comprises lithium and hydrogen, with the exception of two of the compounds, also containing aluminum and silicon, respectively.
Lithium aluminum hydride, tablets, 97% catalog numbers. Used together with titanium tetrachloride, aluminium hydride can add across double bonds. Lithium aluminum hydride is a strong reducing agent and water reactive substance. Lithium aluminum hydride lah is a reagent used extensively in organic synthesis for reduction. Largescale purifications employ a soxhlet extractor. Reacts vigorously with hydroxy compounds such as water, alcohols, carboxylic acids mellor 2 supp.
Commonly referred to as litebh or superhydride, it is a powerful reducing agent. Lithium aluminum hydride can cause headache, muscle weakness, loss of coordination, confusion, seizures and coma. Keep and store away from heatflame, oxidizers, acids, and moisturewater sources. Decomposition of lithium magnesium aluminum hydride request pdf. Lithium aluminum hydride, pellets safety data sheet 07242015 en english us sds id. Lithium aluminum hydride has not been tested for its ability to affect reproduction. Hydrogen can easily be generated from renewable energy. Lithium aluminum hydride powder, reagent grade, 95% synonym.
Hydride transfer to the organic substrate generates an organic anion, which is neutralized either by protic solvent or upon acidic workup. Lithium aluminium hydride cannot reduce an isolated nonpolar multiple bond like cc. Feb 02, 2010 ph3snh is triphenyl tin hydride, this is a reagent which will have very different chemistry to sodium borohydride and lithium aluminium hydride. Lithium aluminum hydride chemical compound britannica. Lialh 4 is a powerful reducing agent compared to sodium borohydride, nabh 4, since the alh bond is weaker and thus less stable than bh bond. Lah can ignite in moist air or because of friction or static sparks. Lithium aluminum hydride is a powerful reducing agent. Decomposition of lithium magnesium aluminum hydride. General handling and storage of lithium aluminum hydride. Indeed, it will reduce almost any molecule that bears a heteroatom. Except where otherwise noted, data are given for materials in their standard state at 25 c 77 f, 100 kpa. The video below shows you a molecule and reaction overview followed by the reduction mechanisms for lialh4 with various carbonyl compounds.
Lithium aluminum hydride lialh4 carbonyl reduction reaction. It is a nucleophilic reducing agent, best used to reduce polar multiple bonds like co. The number of electrons in each of lithiums shells is 2, 1 and its electron configuration is he 2s 1. Lah, lithium alanate, lithium tetrahydroaluminate cas number 16853853. Lithium aluminium hydride, commonly abbreviated to lah, is an inorganic compound with the chemical formula li al h 4. Aluminium hydride has been shown to add to propargylic alcohols. Lah is a colorless solid, but commercial samples are usually gray due to contamination. Warning on the use of lithium aluminium hydride lah powdered lithium aluminium hydride must never be allowed to come into contact with water. P280 wear protective gloves protective clothing eye protection face protection.
The top countries of suppliers are india, china, from which the percentage of lithium aluminium hydride supply is 3%, 94% respectively. Aluminum hydride reduction university of rochester. Lah is very reactive towards h2o in an exothermic process that leads to the potentially dangerous liberation of h2 gas. Handle lah and other pyrophorics under an inert atmosphere, within a glove box, fume hood, or equivalent. Reductions with metal alkoxyaluminium hydrides wikipedia.
Hydrogen can easily be generated from renewable energy sources and is the most abundant element in the universe. Aluminium hydride an overview sciencedirect topics. P264 wash contaminated skin thoroughly after handling. For storing lah, keep sealed under an inert atmosphere. Therefore, there is little need for a more powerful reducing agent, which would presumably be generated if alkylated reagents e. An explosion occurred during its preparation from sodium and aluminum in a medium of tetrahydrofuran chem. Do not attempt to take action without suitable protective equipment. Nov 19, 2015 lithium aluminium hydride, commonly abbreviated to lah, is an inorganic compound with the chemical formula lialh4. But have you ever wondered why exactly is this the case. Process for the preparation of lithium aluminum hydride in. The lithium aluminum hydride and mixed hydride reduction of 3methylcyclohexene oxide bruce rickborn, and wallace e. The reaction was cooled to ambient temperature followed by slow addition of 1 ml 3n koh, 2 ml h2o, and then 3 ml 3n.
All apparatus and reactants should be perfectly dry, and reactions should be run rigorously under nitrogen, with the reaction temperature below 70c at all times. Laboratory, the stereochemistry of hydride reductions. Eye contact rinse immediately with plenty of water. Lithium aluminium hydride, lialh 4, also abbreviated as lah, is a reducing agent commonly employed in modern organic synthesis. However, the double or triple bonds in conjugation with the polar multiple bonds can be reduced. In addition to reducing aldehydes and ketones like nabh4, lialh4 will also reduce carboxylic acids and carboxyl derivatives. Magnesium hydride is the chemical compound with the molecular formula mgh 2. Solid state nmr studies of the aluminum hydride phases sonjong hwang1, robert c. Lithium aluminum hydride is used as a reducing agent in various synthetic organic chemistry reactions. It is highly corrosive to eyes, skin and mucous membranes. Aluminium hydride even reduces carbon dioxide to methane under heating. The crystal structures of the corresponding deuterides, limgald 4 3 and limgald 6, have been. Investigation of lithium metal hydride materials for.
Lithium aluminum hydride is generally immediately available in most volumes. This is a form of nucleophilic acyl substitution that very closely resembles the reduction of an ester, only two steps differ. Show this safety data sheet to the doctor in attendance. Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. Other longterm effects exposure to lithium aluminum hydride can cause loss of appetite, nausea, vomiting, diarrhea and abdominal pain. Sigmaaldrich offers a number of lithium aluminum hydride solution products. Lithium hydride lih, a gray crystalline solid produced by the direct combination of its constituent elements at elevated temperatures, is a ready source of hydrogen, instantly liberating that gas upon treatment with water. Sodium aluminum hydride is a strong reducing agent. Lithium triethylborohydride is the organoboron compound with the formula li et 3 bh. A wide variety of lithium aluminium hydride options are available to you, there are 558 suppliers who sells lithium aluminium hydride on, mainly located in asia. Lialh 4 a compound made by the reaction of lithium hydride and aluminum chloride. Lithium aluminum hydride powder, reagent grade, 95%. Lithium aluminum hydride article about lithium aluminum.
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