Start-up process for improved selectivity in toluene disproporti

Details Start-up process for improved selectivity in toluene disproporti Start-up process for improved selectivity in toluene disproporti

1993-03-31

1995-02-07

Pal, Asok

Chemistry of hydrocarbon compounds

Aromatic compound synthesis

By alkyl or aryl transfer between molecules, e.g.,...

C07C 362

Patent

active

053877322

ABSTRACT:
A process is provided for the disproportionation of a toluene feed stock that includes using an unconventionally low hydrogen to toluene mole ratio during reaction start-up, i.e., until the production of non-aromatics begins to stabilize; thereafter the ratio is increased. Reducing the hydrogen content at the beginning of the reaction substantially lessens any hydrogenation activity, thereby gaining optimum selectivities to benzene at a much sooner rate than that achieved using more conventional hydrogen to toluene ratios. The post start-up increase in hydrogen concentration following stabilized production of non-aromatics is generally believed to enhance the aging character of the catalyst, thereby preserving catalyst life. In practicing the invention, a reaction zone is established loading a metal-modified mordenite catalyst into the reaction zone. A toluene containing feed stock is continuously supplied to the reaction zone. Contemporaneous with the introduction of the toluene, hydrogen gas is introduced into the reaction zone to provide a hydrogen to toluene mole ratio of between 0.5 and 1.5. The feed stock contacts the catalyst forming a disproportionation product containing benzene, xylene(s) and non-aromatic by-products. The disproportionation product is continuously withdrawn and measured to determine its non-aromatic content. When the non-aromatic content of the disproportionation product stabilizes, the amount of hydrogen supplied to the reaction zone is increased.

REFERENCES:
patent: 3667973 (1972-07-01), Mitshe et al.
patent: 3780122 (1973-12-01), Pollitzer et al.
patent: 4665258 (1987-05-01), Butler et al.

Affiliated with

Also associated with

Rating

Start-up process for improved selectivity in toluene disproporti does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Start-up process for improved selectivity in toluene disproporti, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Start-up process for improved selectivity in toluene disproporti will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1111776