Eniehem Company of Italy prepared UV-9 by reacting UV-2 14 with dimethyl sulfate in the presence of potassium carbonate at 3.60 MPa and 160℃ for 6 hours. The conversion rate reached 99%, of which 95.6% was UV-9 and 4.3% was 2,4-dimethoxybenzophenone.
Dimethyl sulfate organic solvent method
Using cyclohexane as solvent, UV-2 14, potassium carbonate and dimethyl sulfate were etherified at reflux temperature. After the reaction, the product was cooled and filtered, and the yield was 50% ~ 54%.
Meng Bo is equivalent to UV-2 14, etherified with n-hexane, and distilled under reduced pressure (0.0 13 Pa) after post-treatment, and the fraction of 190 ~ 2 10℃ was collected and recrystallized with methanol to obtain the product. The yield was calculated as UV-2 14. Kong Xianming and others investigated the effects of solvent, molar ratio of materials and catalyst on the reaction. The results show that too strong or too weak polarity of solvent is not conducive to the reaction, and acetone with medium polarity is the suitable reaction solvent. The phase transfer catalyst did not promote the reaction. The formula of industrial test in 3 m3 reactor is: acetone 9 10 kg, potassium carbonate 322 kg, UV-2 14 830 kg, dimethyl sulfate 489 kg, refluxing for 4 h, distilling acetone for recycling, washing the reaction solution with water, and recrystallizing with ethanol to obtain UV-9, and the recovery rate of acetone reuse 10 is. The Korean patent also reports a method of synthesizing UV-9 using ketone compounds as solvents. Li Bindong et al. used 2,4- dihydroxy benzophenone and dimethyl sulfate as raw materials and n-octyl borate diethanolamine ester as catalyst to synthesize 2- hydroxy 4-methoxybenzophenone. The experimental results show that under the conditions of n (2,4-dihydroxybenzophenone): n (dimethyl sulfate) = 1: 0.55, m (n-octyl boric acid -7, ethanolamine ester) and m (2,4-dihydroxybenzophenone) = 0.02, the reaction temperature is 70℃ and the reaction time is 4.
Dimethyl sulfate aqueous solvent method
This process has not been reported in China. The process of using water as the reaction medium proposed by BASF company in Germany is as follows: firstly, UV-2 14 is dissolved in alkaline solution, and dimethyl sulfate and the remaining alkaline solution are added in batches at room temperature. The total reaction time is 3 h, the yield of crude product is 89%, benzophenone containing dimethoxy is 65438 0.07%, and the yield of refined product after decolorization and purification of activated carbon is 75%, and the melting point is 62 ~.