固载化吡咯烷酮离子液体催化合成聚甲醛二甲醚

摘要

Pyrrolidone acid ionic liquids ([Hnmp]HSO4) was immobilized on HMCM-22 molecular sieves by chemical method and used as the catalyst for the synthesis of polyoxymethylene dimethyl ethers (DMMn).The catalyst was characterized by XRD,FTIR and SEM.The results show that the pyrrolidone acid ionic liquids ([Hnmp]HSO4) can be stability immobilized on HMCM-22.The optimum reaction condition is that the catalyst amount of 2.0％ (mass fraction),feed mass ratio m(DMM)/m(PF) of 2.0,reaction temperature 120 ℃ and reaction time 6 h,m(Ionic liquid)/m(HMCM-22) of 2.0.The conversion of PF and selectivity of DMM3-8 reach 55.41％ and 30.87％,respectively.Compared with the reaction effects of pure ionic liquids or molecular sieve,the yield of DMM3-8 is improved quite a lot.The catalyst can be separated from product phase naturally and exhibits high stability upon reusage.It still remains high activity even after being reused for four times.%以HMCM-22分子筛为载体,化学键合固载吡咯烷酮离子液体,并用于催化合成聚甲醛二甲醚(DMMn).XRD,FTIR及SEM结果表明:吡咯烷酮离子液体可以较好地固载于HMCM-22分子筛上.优选合成聚甲醛二甲醚的反应条件为:催化剂用量为总反应物质量的2.O％,甲缩醛与多聚甲醛的质量比(醇醛比)为2∶1,反应温度为120℃,反应时间为6h,离子液体负载量为2.0.产物中的甲缩醛转化率和DMM38选择性分别可达55.41％和30.87％,与纯离子液体和分子筛催化剂的反应效果相比,DMM38收率得到较大提高,且反应结束后催化剂和产物可自动分离为两相,可直接回收催化剂循环使用.重复使用4次后负载型分子筛催化剂仍能保持很高的活性.