Preparation of CAPS in high purity with low cost

Good's buffers are zwitterionic buffers, which are generally sulfamic acid-based organic compounds, their pH values are relatively stable and does not react with various enzymes and chemical reagents. It is mainly used in the field of biology and medicine. CAPS (N-Cyclohexyl-3-Aminopropanesulfonic Acid) is one of the commonly used Good's buffers in separation of basic drugs by enzymatic chemistry and HPLC. Therefore, its preparation is very important. In order to reduce the reaction conditions, it is generally carried out under the conditions of a catalyst and infrared light irradiation in the production process, while the production cost is increased. And at the same time, the purity of the preparation is difficult to be improved due to the instability of the reaction conditions. This article describes a low-cost method for preparing high purity CAPS.


The preparation process includes:
(1) Preparation of catalyst cerium light rare earth doped nano titanium dioxide: titanium powder and cerium light rare earth are mixed at a weight ratio of 10:1, calcined in a muffle furnace at a temperature of 650°C for 15 h, and then dissolved in distilled water. It was shaken in a water bath, mixed by shaking at 65°C for 60 min, and finally filtered and dried.
(2) The sulfite, bisulfite and propenol are reacted under the special catalyst to prepare 1,3-propanesulfonate, the reaction temperature is 65~90°C, the pH is 6~6.5, and the reaction time is 4~12 hours, the reaction molar concentration ratio is: propenol:bisulfite:sulfite = 1:1.1~1.7:0.1~0.6;
(3) reacting the obtained 1,3-propanesulfonate with carbonic acid at a temperature of 30~50°C for 1~2 h to obtain 1,3-propanesulfonic acid;
(4) The obtained 1,3-propanesulfonic acid and cyclohexylamine are reacted in a water bath at a temperature of 70~90°C for 2~5 h to obtain a crude product of 3-cyclohexylamine-1-propanesulfonic acid;
(5) The crude product of 3-cyclohexylamine-1-propanesulfonic acid is dehydrated by molecular distillation technique at a temperature of 140~150°C and a pressure of 13~266 Pa;

(6) Washing with acetone for 3~7 times to remove cyclohexylamine (the ratio of acetone-washed acetone and crude 3-cyclohexylamine-1-propanesulfonic acid is 5:8), and finally washing 3-cyclohexylamine with distilled water for 3~7 times, and 500 mL of distilled water was used each time to obtain purified 3-cyclohexylamine-1-propanesulfonic acid.


The nanometer titanium dioxide catalyst with rare earth cerium is high in catalytic performance, and the reaction can be carried out without irradiation of infrared light; the sulfite and bisulfite are widely used, and are easily removed in the reaction; during the washing process, the PEEK can be effectively cleaned to ensure maximum acetone savings and lower production costs.


Reference

Yuan Xuesheng. Preparation method of 3-cyclohexylamine-1-propanesulfonic acid. 2016.11.16, CN106117088A


Edited by Suzhou Yacoo Science Co., Ltd.