Synthesis Of TS-1/Ti-MWW Composite Zeolite And Its Catalytic Oxidation Performance

Titanium silicalite zeolite was proved to be able to activate H2O2 under mild conditions and thus to develop a brand green chemical process of selective oxidation of hydrocarbons. TS-1 (MFI) and Ti-MWW (MWW) served as the most typically titanosilicate catalysts in selective oxidation process, they showed lots of advantages both in the synthetic process and applications. While each type titanosilciate also owned some weaknesses. Thus, this thesis was primarily focused on the synthesis of TS-1/Ti-MWW composite zeolite and its catalytic performance for epoxidation of olefins and ketones ammoximation. Meanwhile, the synthesis method of ERB-1 zeolite by using low template contents was also investigated. The main results of the study are concluded as follows:1. TS-1/Ti-MWW composite zeolite was prepared successfully by adopting three different synthetic strategies. The results showed that, we can obtain the target zeolite through adding certain amount of active seed of TS-1 crystal, or introducing extra template or additives into the synthetic system of Ti-MWW zeolite. It was confirmed that the composite zeolite does possess two zeolite composite structures according to the XRD, SEM and BET characterization methods. Then, the possible formation mechanism of composite zeolite sieves was put forward.2. The catalytic performance of TS-1/Ti-MWW composite zeolite for epoxidation of olefins and ketones ammoximation was studied. It showed that, compared with the individual titanosilicates (TS-1 or Ti-MWW) or with the mechanical mixing of these two zeolites, the composite zeolite always exhibited a superior catalytic ability in epoxidation of 1-hexene and allyl chloride reaction. With respect to the liquid phase ammoximation of ketones, composite zeolite also displayed equivalent or even better product selectivity. Thus, it is demonstrated that composite zeolite has the advantages in the catalytic oxidation performance.3. The preparation of MWW-type ERB-1 molecular sieve by using low amounts of template agent (PI) was explored. The results showed that, the contents of template agents for synthesizing ERB-1 molecular sieve can be reduce effectively by introducing certain amount of seed crystal into the synthetic system. However, it is difficult to achieve a pure phase of ERB-1 molecular sieve successfully merely via altering the content of NaOH and boric acid.