Improvements in or relating to the manufacture of carboxylic acids from olefines

摘要

Carboxylic acids are prepared by heating an initial mixture of an olefine, carbon monoxide, water or steam, and a boron-halogen compound, e.g. boron fluoride in anhydrous or hydrated form, aqueous solutions of dihydroxyfluoboric acid, hydrofluoboric acid and, generally, acids obtained from hydrogen fluoride and boric acids. Promoters such as powdered metals or oxides, e.g. nickel, or nickel and mercuric oxides, may be present. Boron fluoride containing up to 5 mols. of water per mol. of fluoride is preferred. The water, other than that present in the catalyst, and carbon monoxide may be in excess with respect to the olefine. Temperatures up to 350, e.g. 150-275 DEG C., and pressures of, e.g. 25-900 atmos. may be used. Apparatus of acid-resisting alloys or coated with chromium or silver is preferably used. In examples: (1) a mixture of CO, C2H4, and steam is passed in countercurrent to a liquid reaction product of hydrofluoric and orthoboric acids at 275 DEG C. and 700 atmos. in a chamber containing active charcoal yielding propionic and other acids; (2) a mixture of CO, C3H6, steam, and dihydroxyfluoboric acid is converted into isobutyric acid; (3), (4), and (5) water-boron fluoride addition compounds are treated first with C2H4 and then CO. Heating under pressure gives a product yielding a propionic acid-boron fluoride addition compound upon distillation or yielding, upon steam distillation, aqueous propionic acid, and a residual water-boron fluoride addition compound which is recycled. U.S.A. Specifications 1,924,763 and 1,924,766 are referred to.