聚丙烯成核剂DMDBS的合成工艺研究

Synthesis of Polypropylene Nucleation Agent DMDBS

以山梨醇、3,4-二甲基苯甲醛为原料,硫酸水溶液为反应介质及催化剂,采用水相沉淀法合成了成核剂DMDBS,筛选出OP-10作为乳化剂,并对合成工艺进行了优化。考察了硫酸浓度、n(醛)∶n(醇)、温度和时间对反应的影响,得出较适宜的工艺条件为:反应温度15℃;反应时间10 h;ω(硫酸)为45%;n(醛)∶n(醇)为1.5∶1.0。粗产品经溶有十八烷基二甲基叔胺的丙酮溶液回流精制,在此条件下DMDBS收率达75.56%,纯度99%以上,熔点252～253℃,质量达到国内外产品水平。

The nucleation agent DMDBS was synthesized by aqueous precipitation and the optimization of the process was studied. Sorhitol and 3,4-dimethylbenzaldehyde were condensed in aqueous H2SO4 in presence of the emulsifier OP-IO. Factors such as the sulfuric acid concentration,molar ratio of aldehyde to alcohol,reaction temperature and reaction time,were investigated;and the preferred preparation conditions were reaction temperature 15 ℃ ,reaction time 10 h,the sulfuric acid concentration 45% ,molar ratio of aldehyde to alcohol 1.5： 1.0. The crude product was refined with N, N-dimethyl-n-oetadecylamine and acetone. Under this condition,the DMDBS was obtained with the yield of 75.56% ,purity above 99%, melting point of 252--253 ℃,giving the product with quality of a high level.