GB294037A - Process for oxidising ethyl alcohol - Google Patents

Abstract

294,037. Holzverkohlungs-Industrie Akt.-Ges., and Fuchs, O. Nov. 14, 1927. Acetaldehyde and its polymers; acetic acid; ethyl acetate; diethyl acetal. - In the catalytic manufacture of acetaldehyde from ethyl alcohol and oxygen-containing gases, the reaction products are dehydrated by cooling and are then treated with an anhydrous, or practically anhydrous, solvent for the aldehyde. Preferably, the condensate obtained by cooling the gases is used to wash the gases prior to the solution of the aldehyde, and from this condensate, which contains unchanged alcohol, acetic acid, and some acetaldehyde, the aldehyde may be recovered by distillation, the acetic acid and part of the alcohol may be recovered as ethyl acetate, and the remaining alcohol may be recovered as such. For dissolving the acetaldehyde from the cooled gases, it is preferred to use solvents which permit the direct further treatment of the aldehyde. For example, the solvent may be ethyl alcohol, in which event the solution, after addition of a small amount of mineral acid, yields diethyl acetal on distillation. The initial material may be dilute alcohol, and the catalysts may be such as are unsuitable for treating absolute alcohol, e.g. finely divided or platinized silver. In one example, a mixture of ethyl alcohol vapour and air is passed over silver wire gauze and the reaction products are cooled to about 15‹ C. in two coolers arranged in series. The gases are then washed in a tower to which the condensate from the first cooler is led, whereafter the acetaldehyde remaining in the gases is removed by washing with aldol. The solution of acetaldehyde in aldol may be treated, e.g. with alkalies, to form aldol. The condensate from the coolers is fractionated in a column to separate acetaldehyde and is then fractionated in a second column, after addition of a small amount of sulphuric acid, a distillate containing ethyl acetate and alcohol being obtained. In another example, the aldehyde is absorbed in acetic acid and the solution is oxidized in known manner to form acetic acid. Reference is made also to the production of paraldehyde.