酸功能化离子液体催化合成聚缩醛二甲醚

对以酸功能化离子液体Hnmp]HSO4、Hnmp]H2PO4、Hnmp]PTSA和PyN(CH2)3SO3H]HSO4催化三聚甲醛和甲醇缩合制备聚缩醛二甲醚(PODEn,n1)的反应进行了研究,考察了催化剂用量、物料配比、温度和时间等对反应活性的影响。结果表明,离子液体的催化活性与其酸性相关。PyN(CH2)3SO3H]HSO4具有较高的催化活性;当PyN(CH2)3SO3H]HSO4的用量为2.0%、甲醇和三聚甲醛的物质的量比为2.0、反应温度110℃、反应压力2.0 MPa、反应时间6 h时,三聚甲醛的转化率和PODE3~8的选择性分别为97.69%和32.54%。反应结束后,PyN(CH2)3SO3H]HSO4与产物可自动分成两相。

Synthesis of poly(oxymethylene) dimethy ethers catalyzed by acidic functionalized ionic liquids

Poly(oxymethylene) dimethyl ethers (PODE n, n>1) were synthesized by the condensation of trioxymethylene (TR) and methanol (MeOH) over the functionalized ionic liquids like Hnmp]HSO₄, Hnmp]H₂PO₄, Hnmp]PTSA and PyN(CH₂)₃SO₃H]HSO₄; the effects of the catalyst amount, raw materials ratio, temperature, pressure and time on the reaction behaviors were investigated. The results showed that the catalytic activity of ionic liquid is related to its acidity. PyN(CH₂)₃SO₃H]HSO₄ exhibits the highest catalytic activity; under the optimum reaction conditions, i.e. PyN(CH₂)₃SO₃H]HSO₄ amount of 2.0%, molar ratio of MeOH to TR of 2.0, 110 ℃, 2.0MPa and reaction time of 6h, the conversion of TR and selectivity to PODE_3~8 reach 97.69% and 32.54%, respectively. Moreover, the ionic liquid PyN(CH₂)₃SO₃H]HSO₄ can be spontaneously separated from product phase after the reaction.