Selective alkylation of toluene with methanol to produce para-Xylene
Abstract
Toluene has been alkylated with methanol over ZSM-5-class zeolite catalysts to produce xylenes and water. A near equilibrium mixture containing 24% of the para isomer was usually observed. Production of over 90% para isomer in the xylene product was achieved when the catalyst was modified by impregnation with phosphorus and with boron compounds. para-Xylene selectivity was also enhanced by coking and coating the catalyst surface with heat-stable polymers. A controlled reduction in the effective dimensions of the catalyst pore openings, and/or channels, along with deactivation of acidic surface sites, has been proposed as a mechanism for the selective production of p-xylene.
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- 1
Present address: 9 Lindsay Drive, Morganville, N.J. 07751.
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Present address: Mobil Research and Development Corporation, Paulsboro, N.J. 08066.