Process for the preparation of an alkylene carbonate and an alkylene glycol
View Patent ↗The invention provides a reaction system for the production of an alkylene carbonate comprising: an epoxidation zone containing an epoxidation catalyst located within an epoxidation reactor; a carboxylation zone containing an bromide-containing carboxylation catalyst located within an alkylene oxide absorber; and one or more purification zones containing a purification absorbent capable of reducing the quantity of bromide-containing impurities in a feed comprising a recycle gas, which purification zones are located upstream from the epoxidation zone; and a process for the production of an alkylene carbonate and an alkylene glycol.
1. A reaction system for the production of an alkylene carbonate and/or alkylene glycol comprising:
an epoxidation zone containing an epoxidation catalyst located within an epoxidation reactor;
a carboxylation zone containing an bromide-containing carboxylation catalyst located within an alkylene oxide absorber; and
a purification zone containing a purification absorbent capable of reducing the quantity of bromide-containing impurities in a feed comprising a recycle gas, which purification zone is located upstream from the epoxidation zone.
2. The reaction system of claim 1 wherein the epoxidation reactor is a shell-and-tube heat exchanger comprising a plurality of reactor tubes positioned substantially parallel to the central longitudinal axis of the epoxidation reactor; wherein the upper ends of the reactor tubes are connected to a substantially horizontal upper tube plate and the lower ends of the reactor tubes are connected to a substantially horizontal lower tube plate; and wherein the epoxidation catalyst is in the form of a packed bed positioned within the reactor tubes.
3. The reaction system of claim 2 wherein the purification zone is located within the reactor tubes.
4. The reaction system of claim 2 wherein the purification zone is located within the epoxidation reactor upstream from the reactor tubes.
5. The reaction system of claim 1 wherein the purification zone comprises a separate purification vessel located upstream from the epoxidation zone which comprises a separate epoxidation reactor.
6. The reaction system of claim 1 wherein the purification absorbent comprises a metal having an atomic number of 22 through 44 or 82.
7. The reaction system of claim 1 wherein the purification absorbent comprises silver.
8. The reaction system of claim 1 wherein the purification absorbent comprises silver, an alkali or alkaline earth metal component, and a support material having a surface area of more than 20 m 2 /g.
9. The reaction system of claim 1 wherein the purification absorbent is a spent epoxidation catalyst which has produced more olefin oxide than the epoxidation catalyst.
10. The reaction system of claim 1 wherein the purification absorbent comprises a basic zeolite.