Study On The Synthesis Process Of Potassium Alcoholate

Potassium alcoholate was widely used in the organic reactions of pharmaceuticals and pesticides because of it’s good selectivity and high activity. But the drawbacks of low purity and high content of free alkali limitted it’s development. In order to solve these problems, this paper studied the process of producing potassium methylate by electrolytic method and the process of producing potassium t-butoxide by alcohol exchange method. The optimum reaction conditions of the two methods were obtained through experiments.The electrolytic method of preparing potassium methylate is divided into two parts:electrolysis and catalytic reaction. The electrolysis part has took all the factors which have an effect on the results of the experiments into consideration. Take the current efficiency as standards, via analyzing the results of single factors experiments and orthogonal experiments, the optimum reaction conditions were obtained:the electrolytic temperature is20℃, the potassium’s content of amalgam potassium is0.2%, the molar concentration of potassium carbonate solution is1mol·L-1, the cathode current density is1.6KA·m-2, the electrolytic time is more than10minutes. Under this condition the current efficiency can be above95%.Mo2C catalyst was used in the catalytic reaction of potassium amalgam and methanol to produce high-purity potassium methylate. Take the content of potassium methylate as standards, via analyzing the results of single factors experiments and orthogonal experiments, the optimum reaction conditions of this part were obtained: the reaction temperature is60℃, the weight ratio of catalyst to potassium amalgam is0.5%, the reaction time is10minutes.The electrolytic preparation of potassium methylate is a two-step joint operation, and we use reflux device on the bottom of the tower, the recovery ratio is1:1. The results show that the reaction of potassium amalgam producing from the electrolytic device and methanol can get a high yield, the content of potassium methylate can be above29%and the content of water is about0.5%. basically unchanged. So it can meet the requirement of the process for potassium methylate with electrolytic method.The alcohol exchange reaction of potassium methylate and t-butoxide can be achieved through reactive distillation technology. The t-butoxide was recycled in the tower and the high-quality product was mined from the bottom of the tower. Take the purity of potassium tert-butoxide as standards, via analyzing the results of single factors experiments and orthogonal experiments, the optimum reaction conditions were obtained:the pressure at the top of the tower is0.5MPa, the feed mole ratio of tert-butoxide and potassium methoxide is12:1, the reflux ratio is7, the total feed flow is65mL-min-1, the temperature on the bottom of the tower is145℃High purity of potassium t-butoxide can be abained under this condition.