GB807605A - Process for the preparation of alpha, beta-epoxypropion-aldehydes - Google Patents

Abstract

a -b -Epoxypropionaldehydes of the formula <FORM:0807605/IV (b)/1> where R is an alkyl radical, are prepared by treating an a -methylidene alkanal with hydrogen peroxide in the liquid phase in the presence of sufficient of a basic agent to maintain a pH of 4-10.5, preferably 6.5-8.5. Suitable basic agents are alkali and alkaline earth oxides and hydroxides, basic-reacting salts such as watersoluble carbonates, bicarbonates and phosphates, and organic bases such as amines. A diluent may be used, such as water, tertiary alcohols, primary alcohols, polyhydric alcohols, ketones, ethers and esters, in which case the preferred concentration of reactants is not more than 50 per cent by weight of the reaction mixture, more preferably 5-15 per cent by weight. Reaction temperatures below 100 DEG C. are preferred, particularly 20-60 DEG C. Preferably the mol. ratio of hydrogen peroxide to a -methylidene alkanol does not exceed 1.5; with pH above 7 this ratio is preferably 1.02-1.2; with pH below 7 it is preferably at least 0.5, more particularly 0.8-1. Polymerization inhibitors and/or peroxide stabilizers may be present. The reaction product may be recovered by flash distillation under approximately neutral conditions using reduced pressure, or by ether extraction. The epoxypropionaldehydes may be used without preliminary separation, e.g. by hydration to dihydroxy aldehydes, or by hydrogenation to glycerols. In examples, acrolein and methacrolein are treated to produce the corresponding epoxyaldehydes. In one example using acrolein the product is hydrogenated in situ to glycerol. Acidic by-products, such as acrylic and methacrylic acids, may be formed. Other a -methylidene alkanols which may be used include a -ethyl, a -hexyl- and a -isopropylacrolein, in general those compounds with 3-9 carbon atoms giving the most favourable yields and conversions. Specification 741,017 is referred to.