Abstract

This study investigated the kinetic patterns of the liquid-phase Prins condensation of propylene with formaldehyde in the range of 120–180°C over H–MFI and H–BEA zeolites. The apparent reaction order with respect to formaldehyde was found to vary between 0.1 and 0.2 for H–BEA and to be close to zero for H–MFI. The apparent activation energy for H–MFI and H–BEA was 26.1±0.6 kJ/mol and 20.0±4.0 kJ/mol, respectively. Based on these results, the reaction was demonstrated to occur in the intradiffusion or transition region; the calculated Thiele modulus and effectiveness factor further confirmed this fact. The diffusion limitations were partially removed by raising the initial formaldehyde concentration, as indicated by an increase in the apparent order of formaldehyde conversion to 1.0 for H–BEA and to 0.4 in the H–MFI case. To describe the substrate transformations observed, a modernized reaction mechanism was proposed.

中文翻译：

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丙烯与甲醛在 H-MFI 和 H-BEA 沸石上的液相缩合动力学

摘要

本研究调查了在 H-MFI 和 H-BEA 沸石上丙烯与甲醛在 120-180°C 范围内液相 Prins 缩合的动力学模式。发现对于甲醛的表观反应级数在 H-BEA 的 0.1 和 0.2 之间变化，而对于 H-MFI 则接近于零。H-MFI 和 H-BEA 的表观活化能分别为 26.1±0.6 kJ/mol 和 20.0±4.0 kJ/mol。基于这些结果，证明反应发生在内部扩散或过渡区域；计算出的蒂勒模量和有效性因子进一步证实了这一事实。通过提高初始甲醛浓度可以部分消除扩散限制，如 H-BEA 的甲醛转化表观顺序增加到 1.0 和 H-MFI 情况下的 0.4 所示。