Selective disproportionation of toluene
US4097543A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1977 |
| Grant date | Jun 27, 1978 |
| Priority date | — |
| Expiry date | Jan 21, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2529/70
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A catalytic process is provided for the selective production of para-xylene by disproportionation of toluene in the presence of a catalyst comprising a crystalline aluminosilicate zeolite having a silica to alumina ratio of at least about 12 and a constraint index within the approximate range of 1 to 12, which catalyst has undergone controlled precoking, i.e. selectivation, by exposing the same to a thermally decomposable organic compound at a temperature in excess of the decomposition temperature of said compound, generally greater than 1000.degree. F., but less than about 1200.degree. F., at a hydrogen to organic compound mole ratio between 0 and 1 to deposit at least about 2 weight percent coke thereon and thereafter contacting toluene with the resulting coke-containing catalyst under disproportionation conditions including a temperature between about 800.degree. F. and 1025.degree. F., and preferably between about 825.degree. F. and 1000.degree. F., at a hydrogen to toluene mole ratio greater than 1 and up to about 10 and recovering a product mixture containing para-xylene in an amount greater than the thermodynamic equilibrium concentration thereof in the total xylenes produce…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.