Short communication Catalytic synthesis of butyric esters with TiSiW_(12)O_(40)/TiO_2

The catalytic activities of TiSiW_(12)O_(40)/TiO_2 in synthesizing ethylester; propyl ester, n-butyl ester; and amyl ester were reported. It was demonstrated thatTiSiW_(12)O_(40)/TiO_2 is an excellent catalyst. Various factors concerned with esterification wereinvestigated. The optimum conditions were found: the mole ratio of alcohol to acid is 1.3:1, themass ratio of catalyst to reactants is 1.5 percent, and the reaction time is 1.0 h. Under theoptimum conditions, the yields are 88.0 percent for ethyl ester, 94.5 percent for propyl ester, 98.6percent for n-butyl ester, 99.1 percent for n-amyl ester, and 96.7 percent for iso-amyl ester,respectively.

Catalytic synthesis of cyclohexanone 1,2-propanediol ketal with H_4SiW_(12)O_(40)/PAn

A new environmental friendly catalyst, H_4SiW_(12)O_(40)/PAn was prepared andidentified by means of FT-IR, XRD and TG/DTA. Cyclohexanone 1,2-propanediol ketal was synthesizedfrom cyclohexanone and 1,2-propanediol in the presence of H_4SiW_(12)O_(40)/PAn The factorsinfluencing tlie synthesis were discussed and the best conditions were found out. The optimumconditions are: molar ratio of cyclohexanone to 1,2-propanediol is 1:1.4, the quantity of catalystis equal to 1.0 percent of feed stocks, and the reaction time is 40 min. H_4SiW_(12)O_(40)/PAn is anexcellent catalyst for synthesizing cyclohexanone 1,2-propanediol ketal and its yield can reachover 96.5 percent.

Preparation of SO_4^(2-)/TiO_2-WO_3 solid superacid and its catalytic activity in acetalation and ketaltion

SO_4^(2-)/TiO_2-WO_3 was prepared and its catalytic activity under differentsynthetic conditions was discussed with esterification of n-butanoic acid and n-butyl alcohol asprobing reaction. The optimum conditions are found that the mass fraction of H_2WO_4 used in thecompound is 12.5 percent, the calcination temperature is 580 deg C, the calcination time is 3 h, andthe soaked consistency of H_2SO_4 is 1.0 mol centre dot L^(-1). Then SO_4^(2-)/TiO_2-WO_3 wasapplied as the catalyst in the catalytic synthesis of eight similar important ketals and acetalsunder the optimum conditions and revealed high catalytic activity. On condition that the molar ratioof aldehyde/ketone to glycol is 1:1.5, the mass fraction of the catalyst used in the reactants is0.5 percent, and the reaction time is 1.0 h, the yields of ketals and acetals can reach 64.2percent-95.1 percent. Moreover, it can be easily recovered and reused.

Synthesis and luminescent properties of Eu^(3+)-doped Na_(24)As_2W_(22)O_(83)

The Eu^(3+)-doped Na^(24)As_2W_(22)O_83 phosphor has been prepared by solidstare reaction from Na_3AsO_4.12H_2O, Na_2WO_4.2H_2O and WO_3, and characterized by elementalanalysis, infrared spectroscopy and powder X-ray diffractometry. According to the measurements withX-ray diffraction, this material belongs to orthorhombic system with its lattice constants: avelence 1.4750 nm, b velence 1.1944 nm, c velence 1.1062 nm, it is consistent with space groupD_2~4-P2_12_12_1 (No.19). The emission and excitation spectra were measured. The luminescentproperties of Eu^(3+)-doped Na^(24)As_2W_(22)O_83 and mechanism of energy transfer were discussed.