PROCESS FOR THE PREPARATION OF WATER-FREE POTASSIUM TERT.-BUTOXIDE

摘要

The subject of the present invention is a continuous process for the preparation of water-free potassium tert.-butoxide from aqueous potassium hydroxide and tert.-butyl alcohol. The reaction takes place in a distillation column filled with filler bodies. The reaction water separating out as well as the water introduced through the starting materials is distilled off at the head of the column with the simultaneous use of a carrier agent. An alcoholic solution of the potassium tert.-butoxide which is withdrawn and then in known manner worked up for isolation of the water free salt collects in the sump of the column. The tert.-butyl alcohol is employed in excess, with the amount being so measured that a 10 to 18% by weight solution of the desired potassium salt in tert.-butyl alcohol is present in the sump of the column. The amount of the tert.-butyl alcohol is so chosen together with the amount of the carrier agent employed that the content of tert.-butyl alcohol in the gas mixture located in the interior of the column lies between 50 and 90% by weight. The sump of the column is kept throughout at boiling temperature. Under these conditions, there is drawn off at the head of the column a gas mixture which consists of 20 to 50% by weight of the tert.-butyl alcohol and 50 to 80% by weight of the carrier agent and contains the steam originating in the reaction as well as the water brought in. The temperature at the head of the column lies, according to the invention, between 65 and 75.degree.C. Cyclohexane or hexane is employed according to the invention as carrier agent.