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Selective synthesis of 3-picoline via the vapor-phase methylation of pyridine with methanol over Ni1-x Co x Fe2O4 (x = 0, 0.2, 0.5, 0.8 and 1.0) type ferrites (2000)

Sreekumar, K. ; Mathew, Thomas ; Rajgopal, R. ; [et al.]

Springer

Catalysis letters 65 (2000), S. 99-105

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ISSN: 1572-879X

Keywords: spinel structure ; ferrites ; pyridine methylation ; electron acceptors

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract A series of Ni–Co ferrites with the general formula Ni1-x Co x Fe2O4 (x = 0, 0.2, 0.5, 0.8 and 1.0) was prepared by a low-temperature hydroxide coprecipitation route. The catalyst systems were characterized by adopting various physico-chemical techniques. Alkylation of pyridine with methanol was carried out in a down-flow vapor-phase reactor. The influence of surface acid–base properties, cation distribution in the spinel lattice and various reaction parameters are discussed. It was observed that the systems possessing x values ≥0.5 are selective for 3-picoline formation, whereas the ones with x values 0 and 0.2 give a mixture of 2- and 3-picolines. Pyridine conversion increased with the progressive substitution of Ni2+ ions by Co2+ ions. Cation distribution in the spinel lattice influences their acidic and basic properties, and these factors have been adequately considered as helpful to evaluate the activity of the systems.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1019081608421

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Catalytic and computer simulation studies of carbon-sulphur bond cleavage over zeolite-YNCL Communication No. 5768. (1994)

Bhawal, B. M. ; Vetrivel, R. ; Reddy, T. Indrasena ; [et al.]

Chichester : Wiley-Blackwell

Journal of Physical Organic Chemistry 7 (1994), S. 377-384

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ISSN: 0894-3230

Keywords: Organic Chemistry ; Physical Chemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Notes: N-Substituted carbonimidodithioic acid dimethyl esters, when reacted with an active methylene compound such as nitromethane, undergo carbon-carbon bond formation followed by carbon-sulphur bond cleavage in the presence of zeolite catalysts to give 1-substituted amino-1-methylthio-2-nitroethenes. This carbon-sulphur bond cleavage is facilitated by the presence of rare earth cations in the zeolite-Y framework. The shape selectivity of the zeolite also plays an important role in this cleavage reaction. Force field calculations adopted for the molecules involved in the reaction indicate the geometry and conformational flexibility of these molecules. The computer-simulated model for the zeolite-Y is correlated with the conformation and shape of the reactant and product molecules to explain the variation in yields obtained in the conversion of substituted dimethyl esters.

Additional Material: 2 Ill.