Glycerol preparation from allyl alcohol

A procedure for the preparation of allyl alcohol introduced by B. Tollens (1870) and later improved calls for heating glycerol with three successive portions of formic acid to a temperature of 260° (li days) and recovery of the allyl alcohol from the distillate (46% yield). Glycerol monoformate is formed and suffers pyrolysis to the unsaturated alcohol, carbon dioxide, and water. 

In the experiments described, a more dilute hydrobromic acid solution may be used, provided that the proportion of sulfuric acid is increased. Aqueous solutions of alcohols may also be used, provided a suitable adjustment is made of the proportion of sulfuric acid. In the allyl alcohol experiment, material was used as obtained from the glycerol-formic acid preparation after one salting-out with potassium carbonate. 

The use of mixtures of glycerol and formic acid for the preparation of allyl derivatives (allyl ch oride and allyl formate) has recently been described by Aschan.2 Allyl alcohol has also been isolated from crude wood alcohol.3 A special method for titrating allyl alcohol has been described.4... 

Although catalyst B is simpler to prepare than catalyst A, it should not be used if the diol is to be distilled directly from the reaction mixture, since residual sodium chlorate can cause explosions when heated with an organic compound. Hydroxylation of allyl alcohol with catalyst A gave glycerol in 67% yield. ri.t-Cyclohcxaiic-l,2-diol was obtained in 76% yield by hydroxylation of cyclohexene with catalyst B. 

Allyl alcohol and its derivatives have been widely employed as intermediates in chemical synthesis and as monomers in polymerization. Although allyl compounds exist widely in nature, they are prepared synthetically for large commercial volumes. Early syntheses of allyl alcohol was based on the preparation of allyl halide intermediates from glycerol or propylene. There are two more recent commercial routes to produce allyl alcohol 1) oxidizing propylene to acrolein and then reacting it with a secondary alcohol, and 2) isomerizing propylene oxide. The route 1) results in a mixture of allyl alcohol and a ketone. The route 2) is preferred to produce a high purity allyl alcohol. 

Uses From 3-chloropropene mainly epichlorohydrin (90 % of the use), glycerol, and allyl alcohol are prepared. The world production in 1997 was 800 0001 allyl chloride. 

Glycerol. Glycerol is the polyhydric alcohol most widely used for the preparation of alkyd resins and is obtained both synthetically and as a byproduct in the manufacture of soap. Most synthetic glycerol is obtained from propylene via allyl chloride ... 

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