1-(3-磺酸基)丙基-3-甲基咪唑磷钨酸盐的制备及其催化性能

以N-甲基咪唑、1,3-丙烷磺内酯、磷钨酸为原料,采用两步法合成了1-(3-磺酸基)丙基-3-甲基咪唑磷钨酸盐(MIMPS]_3PW_(12)O_(40))催化剂。利用X射线衍射、傅里叶变换红外光谱(FTIR)、热重-示差扫描量热分析对催化剂进行了表征,表征结果显示,MIMPS]_3PW_(12)O_(40)催化剂中有8个结晶水,具有磷钨酸的Keggin结构和良好的热稳定性。将该催化剂用于合成乙二醇丁醚醋酸酯(BAC),在最佳工艺条件(反应时间2.0 h,乙二醇丁醚与醋酸的摩尔比1.2:1,反应温度120℃,催化剂与反应物的质量比0.04,带水剂环己烷与反应物的质量比0.3)下,BAC收率可达99.3%。反应后催化剂易分离,重复使用9次后BAC收率为86.8%。FTIR表征结果显示,产物为BAC,没有副产物生成。

Preparation and Catalytic Properties of 1-(3-Sulfonic Group) Propyl-3-Methyl Imidazolium Phosphotungstate

A novel environmental friendly catalyst, 1-(3-sulfonic group) propyl-3-methyl imidazolium phosphotungstate(MIMPS]_3PW_(12)O_(40)) for synthesis of 2-butoxyethyl acetate(BAC) from 2-butoxyethanol and acetic acid was prepared from N-methylimidazolium, 1,3-propanesultone and phosphotungstic acid by a two-step method and was characterized by XRD, FTIR and TG-DSC. The MIMPS]_3PW_(12)O_(40) catalyst existed in Keggin structure, possessed eight molecules of crystalline-water and was thermally stable. Under the optimum reaction conditions for synthesis of BAC: reaction temperature 120 ℃, reaction time 2.0 h, mole ratio of 2-butoxyethanol to acetic acid 1.2 ∶ 1, mass ratio of catalyst to reactants 0.04 and mass ratio of cyclohexane as water entrainer to reactants 0.3, the yield of BAC was 99.3%. The catalyst could be separated easily. After the catalyst was reused 9 times, yield of BAC remained at 86.8%. The product was identified by FTIR and no any by-product was observed.