缩醛化反应合成聚甲氧基二甲基醚研究进展

Advances in acetalization synthesis of polyoxymethylene dimethyl ethers

聚甲氧基二甲基醚具有很高的十六烷值和含氧量,低冷凝点和冷滤点,能显著改善柴油的燃烧特性,有效地提高热效率,大幅度减少NO_x和碳烟的排放,被认为是一种优良的环保型燃油组分。综述了近年来缩醛化反应合成聚甲氧基二甲基醚催化剂体系、反应机理、反应动力学研究进展,已报道的催化剂体系包括液体酸催化剂、固体酸催化剂及离子液体催化剂体系,涉及的反应原料包括可提供亚甲氧基的化合物,如甲醛水溶液、多聚甲醛、三聚甲醛,以及提供封端甲基的化合物,如甲醇、甲缩醛、二甲醚等甲醇下游产品。另外,综述了国内外缩醛化反应合成聚甲氧基二甲基醚反应动力学研究进展,及所建立的反应动力学模型和得到的动力学参数。缩醛化反应及动力学研究正朝着更有利于工业化生产的方向发展,将对工业化生产具有一定的参考意义。

Polyoxymethylene dimethyl ether compounds have high oxygen contents and cetane numbers（CN）, low condensation point and cold filtration point, are promising environmental protection diesel additive to improve diesel combustibility, enhance combustion efficiency, and reduce emission of NOx and carbon smog pollutants. In this review, latest achievement in catalyst system, reaction mechanism and synthesis kinetics of polyoxymethylene dimethyl ether by acetalization reaction was summarized. The catalyst systems included liquid acid, solid acid, and ionic liquid systems in literature. The reaction materials contained end-group（—CH_3, —OCH_3） provider such as methanol, methylal and dimethyl ether, which were downstream products of methanol, and chain segment（—CH_2O—） provider such as 1,3,5-trioxane（TOX）, paraformaldehyde（PF） or formaldehyde（FA）. Synthesis kinetic models and parameters of polyoxymethylene dimethyl ethers were reviewed briefly. The acetalization and kinetics research are moving towards the direction that benefits large scale commercial production.