Some aspects of the bifunctional action of nickel-zeolite catalysts in the conversion of toluene
Twenty-five nickel/zeolite catalysts were prepared by mixing NiO with NaY, NaA, NaX, or CaNaY zeolites or by ion exchange with CaNaY, and tested for the conversion of toluene in hydrogen or nitrogen at 330/sup 0/ to 470/sup 0/C. No conversion took place in the absence of nickel. The systems Ni/NaA or Ni/NaX zeolite were active only for dealkylation. The presence of 80Vertical Bar3< calcium exchanged Na zeolite was necessary for disproportionation to benzene and xylenes. The best conversion was obtained with catalysts precipitated from aqueous solution onto CaNaY and containing 3.2-5Vertical Bar3< nickel. Catalysts prepared by deposition were active only in dealkylation, whereas those obtained by ion exchange catalyzed both dealkylation and disproportionation. The addition of 1-2Vertical Bar3< fluorotoluene or bromobenzene promoted benzene formation in the early reaction stages, and it promoted disproportionation if added to partly deactivated catalysts. The results are discussed in terms of bifunctional catalysis involving metallic and ionic nickel, as well as acidic sites.
- Research Organization:
- Inst. Org. Chem., Bulg. Acad. Sci.
- OSTI ID:
- 6676099
- Journal Information:
- J. Catal.; (United States), Vol. 58:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATALYSTS
CHEMICAL PREPARATION
TESTING
TOLUENE
CONVERSION
CHEMICAL REACTIONS
NICKEL
PROMOTERS
ZEOLITES
ALKYLATED AROMATICS
AROMATICS
ELEMENTS
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MINERALS
ORGANIC COMPOUNDS
SYNTHESIS
TRANSITION ELEMENTS
400201* - Chemical & Physicochemical Properties
400301 - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)