9,10-epoxystearate, respectively. When the mole ratio of sodium borohydride to methyl laurate was increased from 2.5 to 5 and 10 millimoles, the yield of lauryl alcohol increased from 82.9% to 92.8% and 95.8% respectively. The yields of alcohols from other esters can thus be improved by suitably increasing the sodium borohydride to ester ratio.
The presence of both t-butanoland methanol were found to be essential since the replacement of t-butanol with either absolute ethanol, 95% ethanol, isopropanol, or ethylene glycol and of methanol with either water or absolute ethanol yielded little or no alcohol. It was suggested6 that in alcoholic solvents alkoxy borohydride complexes such as [ BH,(OR)4.J are formed whch are more active than sodium borohydnde itself which does not reduce esters to alcohols appreciably.
The sodium alcohol reduction method is laborious and requires skilful operations to avoid stubborn emulsions leading to diminished reactant participation and consequent low product yield. Reduction of esters using lithium aluminium hydride, though provides quantitative conversions, has to be camed out under anhydrous conditions and thus requires moisture-free solvents and dry atmosphere in the apparatus. Compared to these methods reduction with sodium borohydride-t-butanol-methanol, being simple and convenient, appears to be advantageous for reduction of fatty acid esters of varying structures.