OMgBr OMgBr R' / / \ H.CO2C2H5 --> H.C--OC2H5 --> H.C--R' --> CH.OH. \ \ / R' R' R' N. Menschutkin (_Ber._, 1882, 15, p. 1445; _Ann._, 1879, 195, p. 334) examined the rate of esterification of many acids with alcohols. It was found that the normal primary alcohols were all esterified at about the same rate, the secondary alcohols more slowly than the primary, and the tertiary alcohols still more slowly. The investigation also showed that the nature of the acid used affected the result, for in an homologous series of acids it was found that as the molecule of the acid became more complex, the rate of esterification became less. The formation of an ester by the interaction of an acid with an alcohol is a "reversible" or "balanced" action, for as M. Berthelot and L. Pean de St Gilles (_Ann. Chim. Phys._, 1862 (3), 65, p. 385 et seq.) have shown in the case of the formation of ethyl acetate from ethyl alcohol and acetic acid, a point of equilibrium is reached, beyond which the reacting system cannot pass, unless the system be disturbed in some way by the removal of one of the products of the reaction. V. Meyer (_Ber._, 1894, 27, p. 510 et seq.) showed that in benzenoid compounds ortho-substituents exert a great hindering effect on the esterification of alcohols by acids in the presence of hydrochloric acid, this hindering being particularly marked when two substituents are present in the ortho positions to the carboxyl group. In such a case the ester is best prepared by the action of an alkyl halide on the silver salt of the acid, and when once prepared, can only be hydrolysed with great difficulty. Ethyl formate, H.CO2C2H5, boils at 55 deg. C. and has been used in the artificial preparation of rum. Ethyl acetate (acetic ether), CH3.CO2C2H5, boils at 75 deg. C. Isoamylisovalerate, C4H9.CO2C5H11, boils at 196 deg. C. and has an odour of apples. Ethyl butyrate, C3H7.CO2C2H5, boils at 121 deg. C. and has an odour of pineapple. The fats (q.v.) and waxes (q.v.) are the esters of the higher fatty acids and alcohols. The esters of the higher fatty acids, when distilled under atmospheric pressure, are decomposed, and yield an olefine and a fatty acid.