Fu Yongfeng, Guohua Ning, Yun Zhi
2015
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Journal
CIESC Journal
Abstract
2,4-Dichloro-5-fluoropyrimidine was prepared by reaction of 5-fluorouracil(5-FU) and phosphorus oxychloride in the presence of N,N-dimethylaniline(DMA) as acid acceptor. The effect of molar ratio of 5-FU to phosphorus oxychloride, molar ratio of 5-FU to N,N-dimethylaniline, reaction temperature and reaction time was investigated. Furthermore, reaction mechanism was discussed. 5-FU and POCl3 ratio 1:10, 5-FU and DMA ratio 1:1.5, reaction temperature 114℃, reaction time 2 h were the optimum process parameters of synthesizing 2,4-dichloro-5-fluoropyrimidine. Under this process condition, maximum yield of 92.2% of 2,4-dichloro-5-fluoropyrimidine could be obtained. The p H of waste water was then adjusted by adding sodium hydroxide, and the effect of p H on recovery of DMA and yield of by-product disodium hydrogen phosphate was studied. When p H was adjusted to 7, maximum recovery of DMA and maximum yield of by-product disodium hydrogen phosphate could be obtained.