光敏性聚酰亚胺/钌纳米簇中空纤维膜的制备及在费-托合成中的应用

To overcome the deactivation of the catalyst in F-T synthesis and make the distribution of the products controllable,this propsosal aims to design and prepare monodispersed ruthenium cluster/pohotosensitive polyimide (PSPI) hybrid hollow fiber membrane, which could be employed as reactors in the Fischer-Tropsch (F-T)synthesis.In the reactor, H2 and CO permeate through the PSPI membrane where they meet the ruthenium nano-sized clusters, and the reactions occur accordingly. The products will permeate through the membrane and separate from it spontaneously. Due to the adjustability of the permeation of H2 and CO in the PSPI membrane, the selectivity of the products in F-T synthesis could be tuned consequently. In addition, the ruthenium nano-sized clusters were embeded in the PSPI membrane, which makes the nano-sized clusters prevent from aggregation. Thus, the catalytic activity and catalytic life will be kept unaffected. In this proposal, the rules of the sturcture of PSPI and the selective permeation of H2 and CO will be found. The effects of the factors on the F-T synthesis will be investigated as well. Some new and valuable thoughts will be provided with to enhance the catalytic life and selectivity of the products in F-T synthesis.

针对费-托（F-T）合成中催化剂失活和产物分布难以控制的问题，本项目拟设计、制备钌纳米金属簇/光敏性聚酰亚胺（PSPI）中空纤维杂化膜反应器。以颗粒粒径分布窄、形貌结构确定的钌纳米簇与主链光敏性的PSPI制备中空纤维杂化膜，然后集束制备中空纤维管式反应器。该反应器中H2和CO透过PSPI膜时与包埋其中的钌纳米簇相遇并发生催化反应，生成物透过膜而自然与催化剂分离。由于H2和CO在PSPI膜中的透过性能具有可调性，因此可以通过调节PSPI的结构来调控F-T合成产物的选择性；同时钌纳米簇包埋在膜中可有效阻止其团聚和流失，提高其催化活性与寿命。本项目将建立PSPI结构与H2和CO选择性透过的规律，探索其对F-T合成产物选择性的影响，为提高F-T合成催化剂的活性寿命及调控F-T产物的选择性提供新的方法。

本项目以聚乙烯基吡咯烷酮（PVP）为稳定剂和分散剂，正丁醇为溶剂和还原剂，通过化学还原法制备了稳定的单分散钌纳米簇，采用热亚胺化法制得不同单体的聚酰亚胺，通过包埋法和干湿法纺丝，本课题组先后制得聚酰亚胺/钌（PI/Ru）杂化中空纤维膜和聚砜/钌（PSF/Ru）杂化中空纤维膜。利用FT-IR、TEM、XRD、TGA、DSC、SEM、BET等对其进行表征。分析结果表明：钌纳米颗粒平均直径为1-2nm且均匀分散在聚合物中，钌与聚酰亚胺以及聚砜载体中的O、N之间有着一定程度的配位作用,膜的微观结构中指状孔较多，热性能较好。将上述膜反应器应用于费-托合成反应中，PI/Ru杂化中空纤维膜利用PI纤维粉末做反应载体进行反应，PSF/Ru纳米簇杂化中空纤维膜通过管式反应器进行反应，均表现出一定的活性。