Stabilization Of Hydrogen Peroxide Over TS-1 Molecular Sieve

Titanium silicalites-1 (TS-1) has excellent catalytic properties for the selectiveoxidation reactions such as alkene epoxidation, phenol hydroxylation, benzenehydroxylation, and cyclohexanone ammoximation with dilute H2O2 as the oxidantunder moderate conditions. Phenol hydroxylation to prepare diphenol andcyclohexanone ammoximation to prepare cyclohexanone oxime have beenindustrialized. But anatase which forms during the course of synthesis of TS-1catalyzes H2O2 decomposition, thus decreasing H2O2 utility. Accordingly it refrainsfrom applying TS-1 to industry widely. In this dissertation, samples of TS-1 wereprepared under different synthesis conditions, and were characterized by XRD, FT-IR,Raman, SEM, H2-TPR techniques. Allyl chloride epoxidation as probe reaction,activity test was done. Finally, effect of TS-1 synthesis conditions and stabilizer onthe H2O2 stabilization had been investigated. From the above research, the followingdetailed results have been obtained.1. TS-1 was hydrothermally synthesized using TPAOH and TPABr as templateagents. And TS-1 prepared by TPAOH exhibited better catalytic properties.2. The results showed that crystallization temperature and Si/Ti ratio weresignificant factors which affected H2O2 stabilization and that calcinationtemperature and calcination time had no effect on H2O2 stabilization, and thatdecomposition rate of H2O2 over TS-1 was low when TPAOH fromDaXingXingFu Research Institute as the template.3. Compared with purchased TS-1, TS-1 synthesized under the best conditionscatalyzed decomposition reaction of H2O2, and decomposition rate over thelatter was lower. The kinetics of H2O2 decomposition was studied andapparent activation energy was obtained whose value was 85.31 kJ·mol-1.4. Influence of stabilizer species and concentration on H2O2 stabilization wasinvestigated. It was found that hex-sodium metaphosphate, EDTA, phosphateand orgnic stabilizer could improve H2O2 stabilization under TS-1environment, and especially orgnic stabilizer could reduce H2O2decomposition by 29 percent.