A catalyst don’t appear in the overall stoichiometry of the reaction it catalyzes, but it must appear in at least one of the elementary reactions in the mechanism for the catalyzed reaction. 540-36-3, Name is 1,4-Difluorobenzene, molecular formula is C6H4F2. In an article, author is Nocon-Szmajda, Klaudia,once mentioned of 540-36-3, Category: benzoxazole.
Gas transport properties of mixed matrix membranes based on thermally rearranged poly(hydroxyimide)s filled with inorganic porous particles
In this study, we explore the use of two kinds of inorganic sieves, microporous MFI zeolite and mesoporous MCM-41 silica, as fillers to enhance the gas transport characteristics of thermally rearranged (TR) poly(hydroxyimides) (HPI). To the best of our knowledge, this is the first report on the use of these fillers to modify properties of TR HPIs, except for our previous research on MCM-41 filled HPIs based on BPADA dianhydride. In this work, 6FDA-HAB and BPADA-HAB varying in gas permeability and properties were selected as matrices for preparation of mixed matrix membranes (MMM) with the aim of studying the effect of both the kind of filler and a matrix on thermal rearrangement and properties of the resultant TR-MMMs. In addition to pure gas permeability measurements, HPIs and MMMs were examined by WAXD, SEM, TGA, DMA, and tensile tests before and after thermal rearrangement. For all MMM precursors, the permeability increased in proportion to the filler loading (e.g. by 1.2-4.4 times for O-2) while selectivity remained virtually the same. The same effect of improved permeability and maintained selectivity was observed for the series of TR-MMMs; for example, TR-MMM based on 6FDA and filled with 7 wt% of MCM-41 exhibited 6.7 fold higher O-2 permeability over its filled precursor. The permeation properties of the filled membranes showed a strong dependence on both the kind of matrix and filler. The addition of MCM-41 particles to BPADA-HAB increased permeability more than the incorporation of the similar amount of MFI ones, while the contrary was true for 6FDA-HAB. The best result, comprising the position on the upper bound for He/N-2, has been achieved for 6FDA-HAB filled with 25 wt% of MFI, whereas its TR analogue showed the highest 20.4 fold permeability improvement.
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Reference:
Benzoxazole – Wikipedia,
,Benzoxazole | C7H5NO – PubChem