Patent GB-657497-A (GB)
Title: Improvements in or relating to the preparation of lower fatty acid esters
IPC: C07C69/14
Filed: 1948-07-12
Abstract: Esters are made by reacting an olefine of formula <FORM:0657497/IV (b)/1> wherein R is an alkyl radicle containing at least 2 carbon atoms, with a source of formaldehyde under the conditions of reaction in the presence of a fatty acid of 1-4 carbon atoms and in the absence of a catalyst, and separating the ester from the reaction mixture.  Acids specified are propionic, n-butyric, isobutyric and acetic which is preferred.  Many olefines are specified including 2 - methylpropene - 1, 2,3 - dimethylbutene - 1, 2,4 - dimethylhexene - 1, 2 - methyl-3 - ethylpentene - 1, 2,3,3 -, 2,3,4 - and 2,4,4-trimethylpentene-1, 2,6-dimethyl 1-octene-1 and 2-methylnonadecene-1 and preferably certain 2-8 carbon atoms. Mixed olefines may be used diisobutylene being the preferred olefine. Specified sources of formaldehyde are gaseous formaldehyde, alpha-polyoxymethylene and paraformaldehyde which is preferred. Commercial formalin may be used but reaction is best conducted under substantially anhydrous conditions because water hinders the reaction and promotes hydrolysis of the ester to the alkenol.  Preferably the mols. of acid used is 0.5-7.0 and the mols. of olefine 1-4 that of the formaldehyde, highest yields being obtained with a formaldehyde: olefine: acid ratio of 1 : 2 : 1 or 1 : 2 : 2.  Reaction is preferably effected under pressure, e.g. by heating in an autoclave. Temperature of reaction varies with the reactivity of the olefine used but is normally 80-250 DEG  C. with reaction times of 1-60 hours.  Thus with paraformaldehyde, diisobutylene and acetic acid best yields of the acetate are obtained by heating at 160-200 DEG  C. for 2-30 hours and substituting 2-methylheptene-1 for diisobutylene best yields of product are obtained by heating at 140 DEG  C. for 24 hours.  A high boiling product, probably a glycol diacetate, is also obtained.  Acetic anhydride may be used admixed with acetic acid to effect anhydrous conditions.  In examples (1)-(5) paraformaldehyde, diisobutylene and glacial acetic acid are reacted in a bomb in various proportions for about 30 hours at temperatures ranging from 140-165 DEG  C. to produce the acetate of 2-(2,2-dimethylpropyl)-1-buten-4-ol and in (1) a higher boiling product, (6) diisobutylene, paraformaldehyde and a mixture of glacial acetic acid and acetic anhydride are reacted in a bomb at 200 DEG  C. for 30 hours and the above ester obtained, (8) and (9) are as (6) with the addition of high boiling product from (1) reaction being at 165 DEG  C. for 14 and 30 hours respectively, (7) is as (1) with the addition of high boiling product therefrom, reaction being at 160 DEG C. for 30 hours, and in (10) paraformaldehyde, 2-methylheptene-1 and glacial acetic acid are reacted in a bomb at 140 DEG  C. for 24 hours to produce the acetals of 2-n-butyl-buten-1-ol-4.  It is stated that both the acetate of examples (1)-(9) and the alkenol obtained therefrom by saponification may be oxidized with e.g. ozone, to give formaldehyde and a C8 gamma-keto acetate or alcohol respectively. Specification 592,838 is referred to.