نتایج جستجو برای: heteropolyacids
تعداد نتایج: 109 فیلتر نتایج به سال:
We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwa...
Mesoporous silica molecular sieves are a kind of unique catalyst support due to their large pore size and high surface area. Several methods have been developed to immobilize heteropolyacids (HPAs) inside the channels of these mesoporous silicas. The mesoporous silica-supported HPA materials have been widely used as recyclable catalysts in heterogeneous systems. They have shown high catalytic a...
2-Benzoylamino-N-phenyl-benzamide derivatives (5a-h) were prepared from 2-phenyl-3,1-(4H)-benzoxazin-4-one 3 and substituted anilines 4a-h in the presence of a Keggin-type heteropolyacids series (H₃PW12O40·13H₂O; H₄SiW12O40·13H₂O; H₄SiMo12O40·13H₂O; and H₃PMo12O40·13H₂O) as catalysts without solvent and under microwave irradiation. We found that the use of H₃PW12O40·13H₂O acid coupled to microw...
The two heteropolyacids H(3)PW(12)O(40) and H(3)PMo(12)O(40), and their homologous salts (NH(4))(3)PW(12)O(40), and (NH(4))(3)PMo(12)O(40) were prepared and tested in the cationic polymerization of styrene. The results showed that the heteropolytungstates were more reactive than the heteropolymolybdates. It has been found that the yield and the viscosity average molecular weight (M(v)) of polys...
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