Vapor-phase decarbonylation process
View Patent ↗A process is provided for the synthesis of furan and related compounds by vapor phase decarbonylation of furfural and derivatives, using a palladium/alumina catalyst that has been promoted with an alkali carbonate. Catalyst lifetime is improved. The catalyst can be regenerated in situ by feeding a mixture of air and steam, with a composition of between about 2% and about 40% air, to the catalyst bed at a temperature between about 300° C. and about 500° C.
1. A process for the synthesis of a compound as represented by the following structure of Formula (I)
by
(a) providing a compound as represented by the following structure of Formula (II)
in the form of a gas,
(b) optionally, mixing the Formula (II) compound with hydrogen,
(c) heating a Pd/alumina catalyst that has been promoted with an alkali carbonate, and
(d) contacting the Formula (II) compound and the catalyst with water at about 1 to about 30 wt % based on the weight of water plus Formula (II) compound, whereby the Formula (II) compound is converted to a Formula (I) product;
wherein R 1 , R 2 , and R 3 are each independently selected from H and a C 1 to C 4 hydrocarbyl group.
2. The process according to claim 1 wherein R 1 , R 2 , and R 3 are each H.
3. The process according to claim 1 wherein the Formula (II) compound is mixed with hydrogen in a ratio of between about 0.1 and about 5.0 moles of hydrogen per mole of Formula (II) compound.
4. The process according to claim 1 wherein the alkali carbonate is cesium carbonate.
5. The process according to claim 1 wherein contacting the Formula (II) compound and the catalyst to produce a Formula (I) product occurs in the gas phase at a reaction temperature that is in the range of from about 200° C. to about 400° C.
6. The process according to claim 1 where the alkali content of the catalyst is between 1 and 100 mg per g catalyst.
7. The process according to claim 1 , further comprising purifying the Formula (I) product.
8. The process according to claim 1 , further comprising regenerating the catalyst by feeding air, or a mixture of air and steam, or a mixture of air and nitrogen wherein said mixture contains at least 0.1 vol % air, to the catalyst bed at a temperature between about 300° C. and about 500° C. for a time between about 10 seconds and about 100 hours.
9. The process according to claim 1 wherein the process is run at about 13.8 kPa to about 34.5 kPa above ambient pressure.
10. The process according to claim 1 wherein the reaction temperature is increased to a final temperature between about 310° C. and about 370° C. to maintain Formula (I) compound yield.
11. The process according to claim 1 further comprising a step of subjecting the Formula (I) compound to a reaction to prepare therefrom a compound, oligomer or polymer.