含酸DMF溶液的连续脱酸工艺

Continuous Deacidification Process of Acid-containing DMF Solution

开发了一种新型含酸DMF溶液连续脱酸的工艺。该工艺以二甲胺反应转化DMF溶液中的乙酸,实现了难处理的含酸DMF溶液的高效脱酸,同时副产更高工业价值的N,N-二甲基乙酰胺。在管式反应器内,研究了反应温度、反应压力、二甲胺和乙酸摩尔配比、停留时间、DMAC质量分数和水分质量分数对含酸DMF溶液连续脱酸的影响。结果表明:反应温度230℃、反应压力2.0MPa、停留时间43.5min、二甲胺和乙酸摩尔比为1.3∶1、溶液组分质量比为m(DMF)∶m(DMAC)∶m(乙酸)∶m(水)=7∶1∶1∶0时,可使乙酸质量分数下降至0.42%,乙酸转化率可达91%以上,生成高价值产物DMAC的选择性高达100%。

A novel process for continuous deacidification of acid-containing DMF solutions was developed.By the process,the acetic acid in the DMF solution can be converted to N,N-dimethylacetamide through reacting with dimethylamine,to realize the efficient deacidification of acid-containing DMF solution.Meanwhile,N,N-dimethylacetamide with higher industrial value can be produced.In the tubular reactor,the effect of reaction temperature,reaction pressure,dimethylamine/acetic acid molar ratio,residence time,DMAC and moisture mass fractions on the continuous deacidification of acid-containing DMF solutions was studied.It was found that the optimized conditions were as follows:230℃,2.0 MPa,the residence time 43.5 min,the molar ratio of dimethylamine and acetic acid 1.3∶1,m(DMF)∶m(DMAC)∶m(acetic acid)∶m(water)=7∶1∶1∶0.Under the optimized conditions,the mass fraction of acetic acid dropped to 0.42%,the conversion rate of acetic acid was more than 91%,and the selectivity to produce high-value product DMAC was as high as 100%.