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Disclosed is a process for reducing the emission of volatile organic compounds that are produced during the ketonization of carboxylic acids to ketones. The ketonization of carboxylic acids produces a gaseous by-product stream containing carbon dioxide and volatile organic compounds. This gaseous by

Disclosed is a process for reducing the emission of volatile organic compounds that are produced during the ketonization of carboxylic acids to ketones. The ketonization of carboxylic acids produces a gaseous by-product stream containing carbon dioxide and volatile organic compounds. This gaseous by-product stream can be fed to a direct-fired furnace used to heat the ketonization reaction feed streams where the volatile organic compounds are destroyed by combustion in the furnace. The carbon dioxide stream further acts as a diluent for the fuel to the furnace.

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1. A process for reducing the emission of volatile organic compounds from a ketonization process, comprising (i). heating a vaporized feed stream comprising one or more carboxylic acids in a direct-fired furnace comprising a combustion zone to produce a superheated feed stream;(ii). contacting the s

1. A process for reducing the emission of volatile organic compounds from a ketonization process, comprising (i). heating a vaporized feed stream comprising one or more carboxylic acids in a direct-fired furnace comprising a combustion zone to produce a superheated feed stream;(ii). contacting the superheated feed stream with a metal oxide catalyst to form a gaseous product mixture comprising one or more ketones, carbon dioxide, and one or more volatile organic compound by-products;(iii). separating the one or more ketones from the carbon dioxide and one or more volatile organic compound by-products; and(iv). feeding at least a portion of the carbon dioxide and the one or more volatile organic compound by-products to the combustion zone of the direct-fired furnace. 2. The process according to claim 1, wherein the one or more carboxylic acids comprise a carboxylic acid having 2 to 20 carbon atoms. 3. The process according to claim 1, wherein the one or more carboxylic acids comprise acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethyl hexanoic acid, nonanoic acid, or a mixture thereof. 4. The process according to claim 1, wherein the one or more carboxylic acids comprise acetic acid, the one or more ketones comprise acetone, and the one or more volatile organic compound by-products comprise isobutylene, methane, hydrogen, or mixtures thereof. 5. The process according to claim 1, wherein step (ii) is carried out in fixed bed, adiabatic reactor. 6. The process according to claim 1, wherein the superheated feed stream has a temperature of about 350 to about 650° C. and the metal oxide catalyst comprises an oxide of titanium, zirconium, thorium, cerium, lanthanum, or a mixture thereof. 7. The process according to claim 1, wherein the combustion zone comprises a radiative section and a convective section and the carbon dioxide and one or more volatile organic compound by-products are fed to the convective section of the combustion zone. 8. The process according to claim 1, wherein step (iii) comprises cooling the gaseous product mixture by contact with a heat exchanger or a solvent. 9. The process according to claim 8, wherein step (iii) comprises contacting the gaseous product mixture with water in a countercurrent absorber. 10. The process according to claim 1, wherein about 50 to 100 weight percent of the one or more volatile organic compound by-products, based on the total weight of the volatile organic compounds by-products fed to the combustion zone, is converted to carbon dioxide in the combustion zone of the direct-fired furnace. 11. A process for reducing the emission of volatile organic compounds from the production of acetone, comprising (i). heating a vaporized feed stream comprising acetic acid in a direct-fired furnace comprising a combustion zone to produce a superheated feed stream having a temperature of about 350 to about 550° C.;(ii). contacting the superheated feed stream with a catalyst comprising one or more metal oxides of titanium, zirconium, lanthanum, cerium, thorium, or mixtures thereof to produce a gaseous product mixture comprising carbon dioxide, acetone, and one or more volatile organic compound by-products;(iii). contacting the gaseous product mixture with an absorption solvent to produce a crude liquid absorbent stream comprising a major portion of the acetone in the gaseous product mixture and a gaseous by-product stream comprising carbon dioxide, a minor portion of the acetone in the gaseous product mixture, and the one or more volatile organic compound by-products; and(iv). feeding a least a portion of the gaseous by-product stream to the combustion zone of the direct-fired furnace, wherein the combustion zone contains sufficient oxygen for complete combustion of the acetone and the one or more volatile organic compound by-products present in the gaseous by-product stream fed to the combustion zone. 12. The process according to claim 11, wherein the vaporized feed stream further comprises about 70 to about 100 weight percent acetic acid and about 0 to about 30 weight percent water. 13. The process according to claim 11, wherein the one or more volatile organic compound by-products comprise isobutylene, methane, hydrogen, or mixtures thereof. 14. The process according to claim 11, wherein the combustion zone of the direct-fired furnace contains about 10 to about 40 mole percent excess oxygen over the amount required for complete combustion of the acetone and one or more volatile organic compound by-products present in the gaseous by-product stream fed to the combustion zone. 15. The process according to claim 11, wherein the combustion zone comprises a radiative section and a convective section and the residence time of the one or more volatile organic compound by-products in the convective section of the combustion zone is about 0.02 to about 5 seconds. 16. The process according to claim 11, wherein the catalyst further comprises about 0.05 to about 50 weight percent lithium, sodium, calcium, potassium, cesium, or mixtures thereof, based on the total weight of the catalyst, and has a surface area of about 10 to about 400 m2/g of catalyst. 17. A process for the preparation of acetone, comprising (i). heating a vaporized feed stream comprising acetic acid in a direct-fired furnace comprising a combustion zone to produce a superheated feed stream having a temperature of about 350 to about 650° C.;(ii). contacting the superheated feed stream with a catalyst comprising one or more metal oxides to produce a gaseous product mixture comprising carbon dioxide, acetone, and one or more volatile organic compound by-products;(iii). contacting the gaseous product mixture with water to produce a liquid absorbent stream comprising a major portion of the acetone in the gaseous product mixture and a gaseous by-product stream comprising carbon dioxide, a minor portion of the acetone in the gaseous product mixture, and the one or more volatile organic compound by-products;(iv). feeding a least a portion of the gaseous by-product stream to the combustion zone of step (i); and(v). distilling the liquid absorbent stream to produce a distillate comprising a refined acetone product and a distillation bottoms comprising water. 18. The process according to claim 17, wherein step (ii) is carried out in a single or multiple stage adiabatic fixed bed reactor having a temperature of about 300 to about 600° C. over the length of the reactor and an inlet pressure of about 0.7 to about 9 bars absolute. 19. The process according to claim 17, wherein the catalyst comprises one or more metal oxides of titanium, zirconium, cerium, thorium, lanthanum, or mixtures thereof, and has a surface area of about 50 to about 200 m2/g. 20. The process according to claim 17, wherein the weight to weight ratio of gaseous product mixture contacted with water is about 0.5:1 to about 3:1 and the liquid absorbent stream comprises about 20 to about 65 weight percent acetone, based on the total weight of the liquid absorbent stream, about 35 to about 75 weight percent water, 0 to about 3 weight percent acetic acid, and about 0.1 to about 2 weight percent mesityl oxide, isophorone, mesitylene, or a mixture thereof. 21. The process according to claim 17, wherein the refined acetone product comprises about 95 to about 100 weight percent acetone and about 0 to about 5 weight percent water based on the total weight of the refined acetone product.