A manufacturing process for the preparation of .alpha.,.alpha.-branched alkane carboxylic acids, by reacting a mono-olefin or a precursor thereof, with carbon monoxide in the presence of a strong acid catalyst characterized in that the starting olefin is a dimmer C8 or trimer C12 derived from n-butene, which predominantly comprise 2-butene, that the acid catalyst is composed of BF.sub.3/H.sub.3PO.sub.4 in a molar ratio of BF.sub.3:H.sub.3PO.sub.4 in the range of from 0.5:1.0 to 5.0:1.0, or of CF.sub.3SO .sub.3H, that the weight ratio of the catalyst relative to the mono-olefin is in the range of from 1:1 to 10:1, that the reaction is carried out at a temperature in the range of from 60 to 140.degree. C., and with an initial water content in the catalyst system in the range of from 8 to 25 wt %; and vinyl esters and glycidyl esters derived from said carboxylic acids.