GB577992A - Production of allyl alcohol and esters thereof - Google Patents

Abstract

Allyl alcohol or esters thereof are prepared by reacting propylene at a temperature of between 50 DEG and 350 DEG C. with a liquid solution or suspension of selenium dioxide or trioxide or tellurium dioxide or trioxide. Preferably, the selenium or tellurium oxides are dissolved in a suitable solvent and the gaseous propylene dissolved or passed into the solution. The solvent may be an inert liquid or liquids such as water dioxane, benzene, a saturated nitrile or a saturated hydrocarbon, in which case allyl alcohol is obtained or may be a liquid carboxylic acid which reacts with the allyl alcohol formed to produce the corresponding allyl alcohol ester which, if desired, may be subsequently hydrolysed to allyl alcohol. The acid may be present in anhydrous or substantially anhydrous form, such as glacial acetic acid, or acetic acid with acetic anhydride (or a similar mixture of their homologues), or enough water to hydrolyse the ester may be present or formed in the solution or be added as the ester is formed or subsequent to its formation. The gaseous propylene may have other gaseous inert or oxidising materials admixed with it such as air, nitrogen, steam, oxides or peroxides or mixtures thereof. An advantageous reaction temperature is that at which the liquid mixture may be refluxed. If sufficient water be present, the allyl alcohol may be distilled off continuously as its azeotropic mixture, or if the reaction is carried out under anhydrous acid conditions the ester may be distilled off continuously. The solution may be refluxed at atmospheric, reduced or increased pressure. In examples (1) and (2), selenium dioxide was dissolved in a mixture of glacial acetic acid and acetic anhydride, the solution maintained at 100 DEG C. and propylene passed in; after neutralization with aqueous caustic soda, an allyl alcohol water azeotrope was distilled off; (3) selenium dioxide in a solution of glacial acetic acid and acetic anhydride was maintained at 120-130 DEG C. and propylene passed in; allyl acetate was distilled off continuously as soon as formed. Reference is made to the use of propionic acid and its anhydride and their homologues in place of acetic acid and acetic anhydride. Specification 376,306 is referred to. The Specification as open to inspection under Sect 91 relates to the oxidation of propylene and the normal butylenes to the corresponding allyl-type unsaturated alcohols (or esters when an organic acid is present) by reaction with a sulphur oxide, specifically sulphur trioxide, in addition to those mentioned above. It is stated that when sulphur trioxide is used, the oxidation is preferably executed in the absence of a solvent for sulphur trioxide. This subject-matter does not appear in the Specification as accepted.