Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany.
Chemphyschem. 2001 Apr 17;2(4):211-8. doi: 10.1002/1439-7641(20010417)2:4<211::AID-CPHC211>3.0.CO;2-F.
For the off-gas product separation in an ethylene oxide microreactor, new concepts need to be developed. Instead of using the technical process of low-temperature distillation, the performance of gas separation through a dense polymeric membrane was investigated. Different noncrosslinked and crosslinked 6FDA-based polyimides and copolyimides (6FDA=4,4'-hexafluoroisopropylidene diphthalic anhydride) were screened as potential membrane materials. The polymer structure of the membrane material was found to influence the solubility of ethylene oxide and ethylene. The introduction of polar substituents in the polymer backbone increases the solubility selectivity drastically. For permeation experiments in the same pressure range, a novel setup was developed using microstructured membrane supports. With this device, different polymer membranes were tested with respect to the pure gas permeability of ethylene oxide and ethylene as a function of the feed pressure, so that plasticisation effects could be discussed. For different polyimides and copolyimides, ideal ethylene oxide/ethylene selectivities between 3 and 4.5 were found combined with permeabilities between 1.8 and 80.8 barrer.
对于环氧乙烷微反应器中的废气产物分离，需要开发新的概念。本研究不再采用低温蒸馏的技术工艺，而是研究了通过致密聚合物膜进行气体分离的性能。不同的非交联和交联的基于 6FDA 的聚酰亚胺和共聚酰亚胺（6FDA=4,4'-六氟异丙基二邻苯二甲酸酐）被筛选为潜在的膜材料。膜材料的聚合物结构被发现会影响环氧乙烷和乙烯的溶解度。聚合物主链中引入极性取代基会极大地增加溶解度选择性。为了在相同的压力范围内进行渗透实验，开发了一种使用微结构膜支撑体的新型装置。使用该装置，根据进料压力，对不同的聚合物膜进行了环氧乙烷和乙烯的纯气体渗透性能测试，以便可以讨论增塑效应。对于不同的聚酰亚胺和共聚酰亚胺，发现理想的环氧乙烷/乙烯选择性在 3 到 4.5 之间，渗透率在 1.8 和 80.8 巴雷之间。
