Dazhen Jiang

A novel catalyst of copper hydroxyphosphate with high activity in wet oxidation of aromatics

Abstract A novel catalyst of copper hydroxyphosphate (Cu 2 (OH)PO 4 ) that has neither microporous nor mesoporous pores was successfully synthesized by a hydrothermal method. Catalytic data in the hydroxylation of phenol, benzene and naphthol by hydrogen peroxide showed that copper hydroxyphosphate is a very active catalyst. Comparison of various catalysts on phenol hydroxylation suggests that the unusual catalytic activity on the Cu 2 (OH)PO 4 catalyst may be dependent on the unique structure of as-synthesized Cu 2 (OH)PO 4 . Characterization of catalytic phenol hydroxylation over Cu 2 (OH)PO 4 catalyst by electron spin resonance (ESR) gives very strong signals assigned to hydroxyl radical (•OH) species, the intensities of which are linearly related to the catalytic conversion, suggesting that hydroxyl radicals are important intermediates in the catalysis.

Synthesis of mordenite single crystals using two silica sources

Abstract Starting with the batch composition 1 Al 2 O 3 :85 SiO 2 :19 Na 2 O:575 H 2 O, a study was made to determine the effect of various additives and other modifications of the starting composition on the growth of larger mordenite crystals in this system. It was found that synthesis of larger mordenite single crystals requires the use of two silica sources, the addition of an appropriate salt, and higher basicity. Thermogravimetric analysis showed two ranges of weight loss which might be concerned with diffusional restrictions because of the large dimensions of mordenite crystals. MAS n.m.r. indicated that the as-synthesized mordenite should be small port mordenite, and there is no octahedral aluminum in the framework of the products. Results of the dispro-portionation of β-methylnaphthalene over different sizes of mordenite crystals show that the shape selectivity observed in these reactions might be related to diffusional restrictions inside the channels of mordenite.

Catalytic hydroxylation of 2,3,6-trimethylphenol with hydrogen peroxide over copper hydroxyphosphate (Cu2(OH)PO4)

Abstract Catalytic hydroxylation of 2,3,6-trimethylphenol with hydrogen peroxide over copper hydroxyphospate Cu2(OH)PO4 was studied. Catalytic data shows that the Cu2(OH)PO4 catalyst is active, giving the theoretical conversion at 40.2%. The main products in this reaction are trimethylhydroquinone and trimethylbenzoquinone; there is particularly high selectivity for trimethylhydroquinone. When the reaction is carried out in air, the selectivity for trimethylhydroquinone is at 72.2% and when the reaction is carried out under N2, the selectivity is at 94.7%. The other important factors associated with the catalytic properties have been investigated extensively.

Catalytic epoxidation of styrene by molecular oxygen over a novel catalyst of copper hydroxyphosphate Cu2(OH)PO4

Catalytic epoxidation of styrene by molecular oxygen over a novel copper hydroxyphosphate catalyst, Cu2(OH)PO4, was studied. Catalytic data show that the catalyst Cu2(OH)PO4 is very active, and the main products are benzaldehyde and styrene epoxide. Some important factors associated with the catalytic activity and selectivity have been investigated extensively.

Catalytic epoxidation of styrene over copper hydroxyphosphate Cu2(OH)PO4

Catalytic epoxidation of styrene with hydrogen peroxide over copper hydroxyphosphate Cu2(OH)PO4 was studied. Catalytic data shows that the catalyst Cu2(OH)PO4 is very active, and the main products are styrene epoxide and benzaldehyde, particlularly giving high selectivity for styrene epoxide. In contrast, over TS-1 a large amount of phenylacetaldehyde product is formed. Some important factors associated with the catalytic activity and selectivity are investigated extensively.

Copper Promoted Au/ZnO-CuO Catalysts for Low Temperature Water-gas Shift Reaction

Various copper promoted Au/ZnO-CuO catalysts with different atomic ratios of Cu to Zn prepared by means of co-precipitation were tested for the low temperature water-gas shift (WGS) reaction. The catalytic activity of the catalyst depends largely on the ratio of Cu to Zn. The addition of an appropriate amount of copper can considerably improve both the catalytic activity and the stability of the catalyst in comparison with those of copper-free Au/ZnO catalysts. The enhanced reducibility of copper oxide in the Au/ZnO-CuO ternary-component catalysts, which was confirmed by H 2 -TPR, may be related to the high activity and stability of the catalyst for the low temperature WGS reaction.

A novel catalyst of copper hydroxyphosphate (Cu2(OH)PO4) with high activity in hydroxylation of phenol by hydrogen peroxide

A novel catalyst of copper hydroxyphosphate (Cu2(OH)PO4) that has not microporous and mesoporous pores (surface area

27-P-07-High catalytic activity of Fe (III)-substituted aluminophosphate molecular sieves (FeAPO) in oxidation of aromatic compounds

Publisher Summary This chapter discusses high catalytic activity of iron (Fe) (III)-substituted aluminophosphate molecular sieves (FeAPO) in oxidation of aromatic compounds. Iron-substituted aluminophosphate molecular sieves (Fe-AlPO 4 -11, Fe-AlPO 4 -5, and Fe-VPI-5) are catalytically active in the oxidations of aromatic compounds, such as hydroxylation of phenol, benzene, and naphthol as well as the epoxidation of styrene. Catalytic data show that the activities of Fe-AlPO 4 -11, Fe-AIPO4-5 are comparable with that of TS-1 in the oxidation of aromatic compounds. Fe-VPI-5 shows high activity in naphthol hydroxylation by hydrogen peroxide (H 2 O 2 ) while TS-1 is completely inactive because of the small pore size. By comparison of various catalysts, Fe (III) in the framework is considered the major active site in the catalytic reactions.