申请人:Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences
公开号:US20150094497A1
公开(公告)日:2015-04-02
The invention relates to a reaction system and process for continuously preparing polymethoxy dimethyl ether (DMM
3-8
) by a continuous acetalization reaction between an aqueous formaldehyde solution or paraformaldehyde and methanol in the presence of a functionalized acidic ionic liquid as a catalyst. The reaction system of the invention preferably comprises a formaldehyde-concentrating unit, a vacuum-drying unit, an acetalization reaction unit, a product-separating unit and a catalyst-regenerating unit. The process of the invention uses aqueous formaldehyde solution as an initial raw material, which is concentrated in the formaldehyde-concentrating unit to a concentrated formaldehyde of 50˜80 wt. %, and vacuum-dried to paraformaldehyde, or uses paraformaldehyde as raw material directly, then obtains DMM
3-8
by an acetalization reaction. The raw materials of the reaction used in the invention are cheap and available easily, and the utilization rate of formaldehyde is high; an efficient separation between the catalyst and product, as well as the reuse of the catalyst and raw materials, are realized by a separation mode of combining extraction and rectification together.
该发明涉及一种反应系统和工艺,通过在功能化酸性离子液体存在下,连续进行水甲醛溶液或多聚甲醛与甲醇之间的缩醛化反应,从而连续制备聚甲氧基二甲醚(DMM3-8)。该发明的反应系统主要包括甲醛浓缩单元、真空干燥单元、缩醛化反应单元、产品分离单元和催化剂再生单元。该发明的工艺使用水甲醛溶液作为初始原料,在甲醛浓缩单元中浓缩至50~80 wt.%的浓缩甲醛,然后真空干燥得到多聚甲醛,或直接使用多聚甲醛作为原料,然后通过缩醛化反应获得DMM3-8。该发明中使用的反应原料价格便宜且易得,甲醛的利用率高;通过结合萃取和精馏的分离模式,实现了催化剂与产品的高效分离,以及催化剂和原料的再利用。