Weigh 400 kilograms of tetradecyl dimethyl tertiary amine and place it in 1000 liters of enamel reaction kettles, and pump 263 kilograms of hydrobromic acid, 125 kilograms of methanol and 0.4 kilograms of ionic liquid 1-ethyl- The mixture of 3-methylimidazole hydrobromide was stirred and reacted at 50° C., the reaction time was 3 hours, and the reaction was carried out under normal pressure in a nitrogen atmosphere. After the reaction product was vacuum-dried (the drying temperature was controlled at 80° C.), it was added to the 1000L autoclave, and after the reaction kettle was flushed with nitrogen three times, 168 kilograms of dimethyl carbonate and 80 kilograms of dimethyl carbonate were pumped in at a flow rate of 20 kilograms/hour. The methanol mixture was reacted in a closed manner, the reaction temperature was 175° C., the reaction pressure was 1.7 MPa, and the reaction was carried out under stirring for 12 hours. The reaction product was vacuum dried (the drying temperature was controlled at 80°C) to obtain about 553 kg of N,N,N-trimethyl-1-tetradecylammonium bromide with a yield of 99.1% and a purity of 99.1%.
Weigh 1000g of Cetrimide and place it in a beaker, add concentrated hydrochloric acid dropwise (HCl adds a total amount of about 151g), stir with magnetic force, and remove about 80% of the water with a constant temperature water bath after the neutralization reaction. Vacuum drying to obtain the product tetradecyl dimethyl ammonium chloride; weigh 1000g tetradecyl dimethyl ammonium chloride and 330g dimethyl carbonate respectively, add them to the 10L reactor in turn, and drive them away with nitrogen purging After the air in the kettle, the reaction is carried out in a closed state. The reaction temperature is 170 ° C. After the reaction temperature reaches 160 ° C, the stirring is started, and the reaction time is 20 hours. After the reaction is completed, N,N,N-trimethyl-1-tetradecane is prepared. ammonium bromide is about 1040g.
A preparation technique of ion-pair chromatography grade tetradecyl trimethyl ammonium bromide, the steps are as follows:
Put 180g of tetradecyltrimethylammonium bromide raw material into 720mL of solvent (the solvent is prepared from 540mL of anhydrous acetone and 180mL of anhydrous methanol); the obtained mixture is heated to 55°C, stirred for not less than 1h, and stopped Heating, adding 9 g of pretreated activated carbon with a particle size of 100 mesh to the obtained solution in batches under stirring (the activated carbon was soaked in hydrogen peroxide with a mass concentration of 30% for 8 hours, and after separation, soaked in a 6N nitric acid solution for 5 hours, and the solid-liquid separation was carried out. Washed with ionized water until neutral, vacuum dried at 100°C for 4h, vacuum degree was 0.001MPa), then heated to reflux and fully stirred for 3h, stopped heating, filtered under reduced pressure, the filtrate was cooled to room temperature, transferred to a crystallizer, left to stand and analyzed The crystallization temperature was -20 °C; the white crystals precipitated were separated by filtration, the filter cake was pressed dry, the crystals were collected, dried in vacuum, the drying time was 5 h, the temperature was 90 °C, and the vacuum degree was 0.001 MPa to obtain ion-pair chromatography grade N,N ,N-trimethyl-1-Cetrimide 142g, can be sealed and packaged under nitrogen protection.
The obtained product was made into an aqueous solution with a concentration of C=10%, and its ultraviolet absorption value at each wavelength λ was measured:
When λ=240nm, A=0.06;
When λ=250nm, A=0.02;
When λ=260nm, A=0;
When λ=500 nm, A=0.01.