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Deactivation, Regeneration And Reaction Process Of Titanium Silicalite Molecular Sieve Catalysts For The Epoxidation Of Propylene

Posted on:2006-06-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:X W LiuFull Text:PDF
GTID:1101360155958215Subject:Industrial Catalysis
Abstract/Summary:PDF Full Text Request
Propylene oxide (PO) is an important organic chemical feedstocks. Commercially, PO is manufactured either by the chlorohydrin or co-production (Halcon) routes. However the chlorohydrin route generates chlorinated by-products, mainly dichloropropane and CaCl2, which results in equipment erosion and serious environmental pollution, while the co-production route needs large investment and its economic benefit is linked to market of the by-products, namely styrene or tert-butyl alcohol. The invention of titanium silicate-1 (TS-1) by Taramasso in 1983 opened a new route for the selective oxidation of lower carbon alkenes. The method in which TS-1 is used as the catalyst, propylene is oxidized by H2O2 to produce PO and water is its by-products is a cleaner art with high selectivity. Moreover the propylene catalyzed by TS-1 to propylene oxide is one of the most perspective production methods, due to its advantages of high atoms utilization, mild reaction conditions, simple processing technique and its friendly environment.The solvent effect of propylene epoxidation catalyzed by TS-1 is studied systematically in the thesis. At the same time, the deactivation and regeneration of lamina TS-1 catalysts were carried out in detail with the spent lamina TS-1 obtained from single tube magnified experiment used as research objects. The contents are as follows.Firstly, the effect of solvent on the process of PO impregnation on TS-1 by the method of products impregnating was studied. Moreover the reactivity of propylene epoxidation in different solvents over TS-1 was also examined systematically, and the physicochemical properties of spent catalysts were characterized by TG and FT-IR. The results of the research show that, PO are easily to take place polymerize over TS-1 without presence of solvents, which resulted in the decrease of the activity of impregnated TS-1 by PO. The effect is stronger than that of its by-products, such as MME(propylene glycol monomethyl ether) and PG(propylene glycol). The polarity parameter of solvents plays an important role in the polymerization of PO. In the epoxidation of propylene catalyzed by TS-1, the nature of solvent or component and the content of mixed solvents affect obviously the catalytic activity of TS-1, the selectivity to PO, and the distribution and the amount of deposits over spent catalysts. The higher polar experiential parameter Et(30), the higher the catalytic activity of TS-1.Then, the deactivated lamina TS-1 (DeEPO-4) catalysts obtained from single-tube...
Keywords/Search Tags:titanium silicalite, lamina TS-1, propylene, epoxidation, solvent effects, deactivation, regeneration
PDF Full Text Request
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