复合结构活性催化膜的制备及其在PVMR中的应用

There are three inevitable limitations lie in the traditional reaction-separation process: thermodynamic equilibrium limitation, reaction kinetic limitation and mass transfer kinetic limitation. Pervaporation membrane reactor is a new in situ product removal technology in which the product can be selectively removed via pervaporation, thus eliminating the thermodynamic equilibrium limitation of the system, giving rise to an enhanced total conversion and selectivity. we propose preparation of a novel composite catalytically active membrane using phase inversion, adhesionor blending methods, this novel membrane could eliminate the bulk diffusion which is key rate controlling step in traditional inert PVMR, thus greatly reducing the mass transfer resistance. Moreover, benefiting from the porous catalytic layer of the membrane, the diffusion of reactant from the bulk to the catalytic site could be further reduced, thus further improving the reaction-separation coupling performance. More importantly, the application of the PVMR technology can be expanded because the catalytic layer and the selective layer of the composite catalytically active membrane could be separately optimized. We use common organic liquid reactions such as esterification, ketalation as model reactions, the mass transfer mechanism of the components in the PVMR and catalytically active membrane will be investigated through optimizing membrane preparation, reaction and separation properties. Finally, a novel microreactor will be designed to investigate the component mixing, component mobility and mass transfer behavior in an environment of micro space and high V/A ratio, thus determining the coupling enhancement mechanism of the composite catalytically active membrane.

渗透汽化膜反应器（PVMR）将化学反应的热力学平衡、反应动力学以及产物分离的传质动力学三个限制，演变为反应动力学和传质动力学两个限制，通过选择性地原位产物移除打破反应平衡的限制，实现反应转化率和选择性的大幅提升。 针对传统PVMR中液相主体扩散是其传质关键控制步骤的问题，提出制备具有疏松多孔催化层和致密分离层紧密结合的新型复合结构活性催化膜，在消除传统PVMR中主体扩散阻力的同时，降低由反应物向催化位点扩散阻力，实现反应分离耦合过程的强化；复合结构的活性催化膜通过对催化层和分离层单独优化，拓广了PVMR的应用体系和范围；以酯化、缩酮等液相常温平衡反应为探针体系，通过优化制膜、反应、分离三类参数，研究各组分在膜及PVMR内传质规律；设计微尺寸反应器，探索微小尺度及高空速条件下膜反应器内混合、流动及传质扩散的特性，阐明复合结构活性催化膜的强化机理。

平衡反应是自然界中的普遍现象，由于热力学的限制，平衡反应的转化率一般难以达到一个较高的水平，催化膜反应器通过反应分离耦合过程可打破反应的热力学平衡限制。本研究针对传统惰性催化膜反应器中存在分离速率低、产物不能真正原位分离、反应与分离速率难以匹配等问题，通过对反应规律和分离规律的研究，利用实验研究与模型分析相结合，对膜反应器过程中反应与分离过程的热力学和反应动力学及传质性能进行了剖析，提出了一种基于浸没相转化技术制备集催化与分离作用于一体的新型活性催化膜及其膜反应器结构。本研究分别以酯化、缩酮、缩醛等反应为探针反应，固体酸、生物酶、硫酸锆为催化剂，考察了催化剂在探针反应中的动力学特征及反应分离耦合性能；针对待移除组分特点，优化了活性催化膜的多层结构；通过对催化膜及膜反应器的优化设计，实现了反应产物在催化位点的“真正原位”分离，实现了反应液主体中待分离产物水的“零水”状态。