Integrated methods for chemical synthesis
Among other things, the present invention encompasses the applicant's recognition that epoxide carbonylation can be performed industrially utilizing syngas streams containing hydrogen, carbon monoxide and varying amounts carbon dioxide. Contrary to expectation, the epoxide carbonylation reaction proceeds selectively in the presence of these mixed gas streams and incorporates excess CO in the syngas stream into valuable chemical precursors, resulting in hydrogen streams substantially free of CO. This is economically and environmentally preferable to performing WSGR which releases the excess carbon as CO2. The integrated processes herein therefore provide improved carbon efficiency for processes based on coal or biomass gasification or steam methane reforming.
1. A method for the integrated production of chemicals comprising the steps of:
a) in a first reaction zone, contacting an epoxide in the presence of a carbonylation catalyst with a syngas stream containing hydrogen and carbon monoxide thereby causing carbon monoxide in the industrial gas stream to react with the epoxide to provide an epoxide carbonylation product,
b) removing an upgraded gas stream from the first reaction zone wherein the upgraded gas stream has a higher hydrogen to carbon monoxide than the starting syngas stream, and
c) in a second reaction zone, utilizing the upgraded gas stream to conduct a second chemical process requiring a hydrogen to CO ratio higher than the ratio in the industrial gas stream utilized in step (a).
2. The method of claim 1 , wherein the syngas stream has a molar hydrogen to CO ratio between 0.5:1 and 1.2:1, and the upgraded gas stream has a hydrogen to CO ratio of at least 1.9:1.
3. The method of claim 1 , wherein the second chemical process comprises Fischer Tropsch synthesis.
4. The method of claim 1 , wherein the second chemical process comprises reaction on a fuel cell.
5. The method of claim 1 , wherein the second chemical process comprises hydrogenation.
6. The method of claim 1 , wherein the epoxide carbonylation product is selected from the group consisting of: optionally substituted beta lactone, optionally substituted succinic anhydride, and a polyester resulting from alternating polymerization of CO and the epoxide.
7. The method of claim 1 , wherein the epoxide is ethylene oxide.
8. The method of claim 7 , wherein the carbonylation product is beta propiolactone.
9. The method of claim 7 , wherein the epoxide carbonylation product is succinic anhydride, and the upgraded gas stream has a molar hydrogen to CO ratio greater than 5.1.
10. The method of claim 9 , wherein and the upgraded gas stream has a hydrogen to CO ratio greater than 10:1, greater than 20:1, greater than 50:1, greater than 100:1, or greater than 1,000:1.
11. The method of claim 9 , wherein the upgraded gas stream is substantially free of carbon monoxide.