Alkylation, heteropoly compounds

The existence of a significant interaction between the heteropolyanion and the carbenium ion is supported by the presence of alkyl-heteropoly complexes. Knoth and Harlow (7(57) synthesized O-alkylated compounds such as [(C2H5)30]3PWi2037, where a C2H5 cation is bonded to the polyanion. Fameth et al. (168) and Lee et al. (169) reported the formation of methyl groups and... 

Hydrogen peroxide and alkyl hydroperoxides are important oxidants in organic synthesis, but they usually need to be activated by catalysts such as tungsten, molybdenum, and titanium oxides. Heteropoly compounds are good catalysts for oxygenation of olefins or paraffins and oxidative cleavage of vic-diols. 

Liu S. Z., Zhang Z. W., Wang J., Du Z. L. and Dai S. X., Studies on the preparation, structure and prpperties of dilongchain alkyl group rare earth heteropoly compounds LB films, Acta Chim. Sinica, 59 (2001) pp.339-343. 

Alkylation of Toluene with Methanol on Heteropoly Compounds p-xylene selectivity... 

Oxidation of alkyl benzene using heteropolycompounds are effective in presence of oxidants like hydrogen peroxide and t-butylhydroperoxide. Vanadium substituted heteropolymolybdates are more effective than unsubstituted heteropoly compounds. Both side chain and products with oxidation in the aromatic ring are observed in presence of heteropoly compound-hydrogen peroxide system whereas only side chain oxidized products were observed in presence of heteropolycompound-t-butyl hydroperoxide system. This difference in activity can be due to the formation of different active intermediate species. 

Mizuno N, Misono M (1998) Heterogeneous eatalysis. Chem Rev 98 199-218 Briand LE, Baronelti LE, Thomas HJ (2003) The state ofthe artonWells-Dawson heteropoly-compounds a review of their properties and applications. J Mol Catal A Gen 256 37-50 Hemender K, Reddy A, Pandurange Reddy V, Veeragaiah V (1992) Versatile synthesis of 6-alkyl/aryl-l/7-pyrazolo[3,4-d]pyrimidin-4[5//]-ones. Ind J Chem 316 163 166 Misono M, Okuhara T (1993) Solid superacid catalysts. Chem Tech 23(1I) 23 29 Kozhevnikov IV (1987) Advances in catalysis by heteropolyacids. Russ Chem Rev 56 811-825 Izumi Y, Urabe K, Onaka M (1992) Zeolite, elay and heteropoly acid in organic reaction, vol 99. Kodansha, Tokyo... 

Typic2il examples of acid-catalysis of heteropoly compounds are as follows Dehydration of methanol, - > ethanol, - - propanol - - - -"- "- > and butanol, conversion of metanol or dimethyl ether to hydrocarbons, etheration to form methyl /-butyl ether, esterifications of acetic acid by ethanol and pentanol, decomposition of carboxylic acid and formic acid, alkylation of benzene by ethylene and isomerization of butene, o-xylene and hexane. ... 

In addition to CuCfi, some other compounds such as Cu(OAc)2, Cu(N03)2-FeCl.i, dichromate, HNO3, potassium peroxodisulfate, and Mn02 are used as oxidants of Pd(0). Also heteropoly acid salts comtaining P, Mo, V, Si, and Ge are used with PdS04 as the redox system[2]. Organic oxidants such as benzo-quinone (BQ), hydrogen peroxide and some organic peroxides are used for oxidation. Alkyl nitrites are unique oxidants which are used in some industrial... 

Cs" salts catalyse the acylation of toluene, p-xylene and m-xylene with crotonic acid. Some alkylation of aromatic compounds with crotonic acid also takes place. Heteropoly acid was found to be more active than zeolites HY and H-Beta in the acylation. 

---