ZSM-5 synthesis gels were aged during 18-72 h at temperatures between 30 and 90 8C. After addition of the cationic surfactant cetyltrimethylammonium bromide these so called ''seeding gels'' were crystallised at 120 or 150 8C. From gels aged at 60 8C, ZSM-5 crystals possessing uniform mesopores with
Synthesis of mesoporous ZSM-5 by one-pot method in the presence of polyethylene glycol
β Scribed by Guodong Chen; Lin Jiang; Lingzhi Wang; Jinlong Zhang
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 712 KB
- Volume
- 134
- Category
- Article
- ISSN
- 1387-1811
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β¦ Synopsis
Mesoporous ZSM-5 was synthesized by using dual templates and one step hydrothermal crystallization method under alkali conditions. Mesopores were created by using cetyltrimethylammonium bromide (CTAB) as the template and the crystallized pore wall framework was formed by using tetrapropylammonium bromide (TPAB) as the template. The specific influences of the polyethylene glycol (PEG) and ammonium fluoride (NH 4 F) addition, hydrothermal crystallization temperature, TPAB/Si and Al/Si ratio to the mesostructure and crystallinity of the obtained samples were carefully studied. In this system, PEG plays an important role in the maintenance of the mesoporous pore ordering and the zeolite crystallinity. Moreover, the study on the hydrothermal stability of the sample with best mesoporous pore ordering and zeolite crystallinity showed this kind mesoporous zeolite has extremely high hydrothermal stability in boiling water.
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Primary, secondary, tertiary, allylic, and benzylic halides are converted efficiently into symmetric disulfides in high yields using thiourea as the sulfur atom source. The reactions are odorless and are performed at 30-35 Β°C in wet PEG-200 using MnO 2 as an oxidant.
In the presence of a copper phthalocyanine complex (CuPc), it is possible to synthesize ZSM-5 zeolite containing the complex, and the crystallinity is good, provided that the amount of CuPc trapped is lower than the number of channel intersections where it can be located without too much distortion.