Methylated Products and Homologation to Higher Alcohols

The alkylation of toluene with methanol has been investigated for many years as a potential alternative route to / - Qflene, ethylbenzene, and styrene. Conventional / -xylene production from petroleum reformate requires costly purification and separation from jQ lene isomers and other aromatics. A process that selectively produces /)-xylene could have a significant commercial impact by eliminating the need for p-xylene separation. Furthermore, styrene or ethylbenzene production from methanol and toluene is desired as part of the development of processes based on Cl feedstocks rather than ethylene or propylene feedstocks [48], Para- xyl ae is used primarily in terephthalic acid production, a major component of polyester manufacture. 

Toluene alkylation with methanol using Friedel-Crafts catalysts results in mixed products since isomerization reactions and fiirther methylation of the desired products readily occur under these reaction conditions [49,50]. Recent work has therefore been aimed at the development of processes with high selectivity, and zeolite catalysts appear to have the most promise in this regard. 

Catatysta HZSM-5 Coated HZSM-5 P-HZSM-5 B-HZSM-5 

Toluene-medianol molar feed ratio Conversion, % 1.5 1.4 I 2 

Cata t deactivation during toluene alkylation with methanol over B-HZSM-5 catatyst Terrperature 600°C, WHSV =3.8, pressure = 0.1 MPa, and toluene-methanol molar ratio = 2 l. Toluene conversion (circles) jgiene wt% in or nic product (open squares) and / -3giene wt% of total xylenes (filW squares). 

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