GB246526A - Process of esterification - Google Patents

Abstract

246,526. U.S. Industrial Alcohol Co., (Assignees of Arentz, F. B.). Jan. 26, 1925, [Convention date]. Esters.-In a process of esterification, a reaction mixture containing the acid and alcohol is distilled so as to produce, a constant boiling mixture which is condensed to form separate liquid layers, one of which contains a high percentage of water and is removed from the apparatus, while the entire layer containing the other constituents is returned to the renuxing column of the reaction vessel until no more water is evolved. The process is described for the preparation of normal butyl acetate, but may be used for the production of other esters, such as isobutyl acatate, amyl acetate, normal butyl tartrate, amyl phthalate, butyl phthalate, ,and amyl formate. In the preparation of butyl acetate, a mixture of butyl alcohol and concentrated or glacial acetic acid is heated with a small quantity of sulphuric acid as a catalyst in a still 1 surrounded by a heating jacket 2. The still is connected to a column 5, and dephlegmator 9, the condensates from which return to the still through pipes 7 and 12. After a substantial amount of ester has been formed, the mixture is slowly distilled, and the vapours are condensed in a condenser 14. The condensate passes to a separating chamber 18 fitted with a sight-glass 20, and separates into two layers 21, 22. The upper layer 21 consists mainly of butyl acetate and butyl alcohol and is returned to the column 5 through a pipe 23. The lower layer consists mainly of water and is removed by a pipe 24. When no more water separates out in the chamber 18, the contents of the still are neutralized with caustic soda and then rectified or otherwise treated to recover the ester. In making butyl tartrate, the vapours driven off from the still consist mainly of butyl alcohol and water, and separate into an upper alcohol layer, which is returned to the still, and a lower water layer. When the reaction is completed, the excess alcohol is removed by the vacuum distillation, and the crude ester is washed and rectified.