A novel metal-organic framework, [Zn(2)(OH)(Hcht)(4,4'-bpy)](n).4nH(2)O (1) (H(4)cht = cyclohexane-1,2,4,5-tetracarboxylic acid and 4,4'-bpy = 4,4'-bipyridine), was synthesized by the hydrothermal reaction of Zn(NO(3))(2).6H(2)O, 4,4'-bipyridine, and cyclohexane-1,2,4,5-tetracarboxylic acid in the presence of sodium carbonate. The complex was obtained by controlling the ratio of the starting ma...

the surface of sba-15 was modified by diphenylphosphine; then, it was treated with butane sultone and sulfuric acid to obtain brønsted acid ho3s-phosphonium based ionic liquid functionalized sba-15 with hso4- as a counteranion. it efficiently catalyzed synthesis of pyrano[3,2-c]chromenone derivatives through the reaction of 4-hydroxycoumarin and chalcones at 60 °c in water/ethanol. good yields,...

The location of Brønsted acid sites within zeolite channels strongly influences reactivity because of the extent to which spatial constraints determine the stability of reactants and of cationic transition states relevant to alkane activation catalysis. Turnover rates for monomolecular cracking and dehydrogenation of propane and n-butane differed among zeolites with varying channel structure (H...

The catalysis of n-butane isomerization over iron-promoted tungstated zirconia (F1.2WZ) and platinum–iron-promoted tungstated zirconia (P/F1.2WZ) catalysts was studied and correlated to the catalyst characterization results. In the singly promoted F1.2WZ catalyst, we suggest that the iron species promotes the n-butane isomerization reaction through a redox effect. The formation of W–O–Fe linkag...

The synthesis of polyimides (PIs) containing polydimethylsiloxane (PDMS) with controlled chain length and the formation higher-order structures were studied. Polycondensation was carried out using diphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA) diamine oligomers having amino groups on both ends PDMS. obtained poly(amic acid) (PAA) PI showed good solubility in several common polar solvents...

Rice bran oil was extracted using hexane, as well as subcritical butane and propane. The quality of rice bran oils obtained using these three solvents was comparatively studied. The results showed that subcritical fluid extraction oil showed higher concentrations of health-conducive components (such as vitamin E, oryzanol, and phytosterol) compared with hexane-extracted oil. Extraction solvent ...

Sulfated zirconia (SZ), unpromoted and promoted with 0.5–2.0 wt% Mn or Fe, was investigated by in situ IR and UV–vis spectroscopy during activation at 723–773 K and interaction with n-butane at 298–323 K. During start-up of the catalysts, the isomerization rate increases with the amount of water that is being formed, consistent with an activation of n-butane via oxidative dehydrogenation. Sulfa...

one-pot preparation of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles has been conducted in the presence of poly(4-vinylpyridinium butane sulfonic acid) hydrogen sulfate, p(4vpbsa)hso4, as an efficient dual acidic catalyst under solvent-free conditions. reusability of the catalyst, easy work-up procedure, eco-friendly reaction conditions, short reaction times and high yields of th...

The surface of SBA-15 was modified by diphenylphosphine; then, it was treated with butane sultone and sulfuric acid to obtain Brønsted acid HO3S-phosphonium based ionic liquid functionalized SBA-15 with HSO4- as a counteranion. It efficiently catalyzed synthesis of pyrano[3,2-c]chromenone derivatives through the reaction of 4-hydroxycoumarin and chalcones at...