Institute for Organic and Macromolecular Chemistry, Heinrich-Heine University of Duesseldorf, Universitaetsstr. 1, 40225 Duesseldorf, Germany.
Beilstein J Org Chem. 2010 Aug 12;6:789-800. doi: 10.3762/bjoc.6.86.
Functionalized copolyimides continue to attract much attention as membrane materials because they can fulfill the demands for industrial applications. Thus not only good separation characteristics but also high temperature stability and chemical resistance are required. Furthermore, it is very important that membrane materials are resistant to plasticization since it has been shown that this phenomenon leads to a significant increase in permeability with a dramatic loss in selectivity. Plasticization effects occur with most polymer membranes at high CO₂ concentrations and pressures, respectively. Plasticization effects are also observed with higher hydrocarbons such as propylene, propane, aromatics or sulfur containing aromatics. Unfortunately, these components are present in mixtures of high commercial relevance and can be separated economically by single membrane units or hybrid processes where conventional separation units are combined with membrane-based processes. In this paper the advantages of carboxy group containing 6FDA (4,4'-hexafluoroisopropylidene diphthalic anhydride) -copolyimides are discussed based on the experimental results for non cross-linked, ionically and covalently cross-linked membrane materials with respect to the separation of olefins/paraffins, e.g. propylene/propane, aromatic/aliphatic separation e.g. benzene/cyclohexane as well as high pressure gas separations, e.g. CO₂/CH₄ mixtures. In addition, opportunities for implementing the membrane units in conventional separation processes are discussed.
功能化共聚酰亚胺继续作为膜材料吸引了很多关注，因为它们可以满足工业应用的需求。因此，不仅需要良好的分离特性，还需要高温稳定性和耐化学性。此外，膜材料抗增塑作用非常重要，因为已经表明这种现象会导致渗透性显著增加，选择性急剧下降。在高 CO₂浓度和压力下，大多数聚合物膜都会发生增塑作用。丙烯、丙烷、芳烃或含硫芳烃等较高的烃类也会发生增塑作用。不幸的是，这些成分存在于具有高商业相关性的混合物中，可以通过单膜单元或混合工艺进行经济分离，其中常规分离单元与基于膜的工艺相结合。在本文中，根据非交联、离子交联和共价交联膜材料的实验结果，讨论了含羧基的 6FDA（4,4'-六氟异丙基二邻苯二甲酸酐）共聚酰亚胺的优点，这些结果涉及烯烃/烷烃（例如丙烯/丙烷）、芳烃/脂肪烃（例如苯/环己烷）的分离以及高压气体分离（例如 CO₂/CH₄ 混合物）。此外，还讨论了在常规分离工艺中实施膜单元的机会。
