# US 5,700,368 A · Treatments to reduce aldol condensation and subsequent polymerization in caustic acid gas scrubbers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,368 A - Document ID: US5700368A - Status: Granted - Kind: A - Application number: 08/450,366 - Filed: 1995-05-25 - Granted: 1997-12-23 - Earliest claimed: 1995-05-25 - Assignees: Baker Hughes Incorporated - Inventors: Glenn L. Roof - Web page: https://patentgrep.com/patent/US5700368A ## CPC - C10G 19/02: with aqueous alkaline solutions - B01D 53/1493: {Selection of liquid materials for use as absorbents} - C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract The present invention provides a number of agents that are useful to inhibit aldol condensation in caustic scrubbers. Preferred agents include, but are not necessarily limited to benzoic hydrazide, hydroperoxides, hydrogen peroxide, salts of hypochlorous acid, nitroalkanes, monoethanolamine, peroxyesters, and N,N-dialkylhydroxylamines. ## Claims ### Claim 1 A method for inhibiting aldol condensation in caustic scrubbers comprising the step of treating a caustic scrubbing solution comprising hydrocarbons with an inhibiting agent in an amount sufficient to inhibit said aldol condensation, wherein said inhibiting agent is selected from the group consisting of benzoic hydrazide, hydroperoxides, hydrogen peroxide, salts of hypochlorous acid, nitroalkanes, monoethanolamine, peroxyesters, and N,N-dialkylhydroxylamines. ### Claim 2 A method for inhibiting aldol condensation in caustic scrubbers comprising the step of treating a caustic scrubbing solution comprising hydrocarbons with an inhibiting agent in an amount sufficient to inhibit said aldol condensation, said inhibiting agent being selected from the group consisting of benzoic hydrazide, tertiary-butyl hydroperoxide, hydrogen peroxide, NaOCl, Ca(OCl).sub.2, nitromethane, monoethanolamine, tertiary-butyl perbenzoate, and N,N-diethylhydroxylamine. ### Claim 3 (depends on 1) The method of claim 1 where wherein said inhibiting agent is selected from the group consisting further of isothiuronium salts, primary amines, acetophenone, dibutyl-amine, and iodine. ### Claim 4 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises benzoic hydrazide. ### Claim 5 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises a hydroperoxide. ### Claim 6 (depends on 5) The method of claim 5 wherein said hydroperoxide is selected from the group consisting of tertiary-butyl hydroperoxide and cumene hydroperoxide. ### Claim 7 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises hydrogen peroxide. ### Claim 8 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises a salt of hypochlorous acid. ### Claim 9 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises monoethanolamine. ### Claim 10 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises a peroxyester. ### Claim 11 (depends on 10) The method of claim 10 wherein said peroxyester is selected from the group consisting of tertiary-butyl perbenzoate, tertiary-butyl peroxyacetate, tertiary-butyl peroxypivalate, tertiary-butyl peroxy-2-ethylhexanoate, and tertiary-amyl peroxy-2-ethylhexanoate. ### Claim 12 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises a nitroalkane having the structure R--NO.sub.2 wherein R is selected from the group consisting of straight, branched, and cyclic alkyl groups having between about 1-8 carbon atoms. ### Claim 13 (depends on 1) The method of claim 1 wherein said inhibiting agent comprises nitromethane. ### Claim 14 (depends on 3) The method of claim 3 wherein said isothiuronium salt comprises benzyl isothiuronium chloride; said primary amine is selected from the group consisting of an arylamine, an aralkylamine, an ethereal amine, and a cyclic alkyl amine. ### Claim 15 (depends on 3) The method of claim 3 wherein said inhibiting agent comprises a primary amine selected from the group consisting of aniline, benzylamine, 3-methoxypropylamine, and cyclohexylamine. ### Claim 16 (depends on 1) The method of claim 1 wherein said hydrocarbon stream contains a molar concentration of reactive carbonyls, and wherein said hydrocarbon stream is treated with a molar amount of said inhibiting agent that is at least substantially the same as said molar amount of said reactive carbonyls. ### Claim 17 A caustic scrubbing solution comprising hydrocarbons and an inhibiting agent in an amount sufficient to inhibit aldol condensation, wherein said inhibiting agent is selected from the group consisting of benzoic hydrazide, hydroperoxides, hydrogen peroxide, salts of hypochlorous acid, nitroalkanes, monoethanolamine, peroxyesters, and N,N-dialkylhydroxylamines. ### Claim 18 (depends on 17) The caustic scrubbing solution of claim 17 wherein said inhibiting agent is selected from the group consisting of benzoic hydrazide, tertiary-butyl hydroperoxide, hydrogen peroxide, NaOCl nitromethane, monoethanolamine, tertiary-butyl perbenzoate, and N,N-diethylhydroxylamine. ### Claim 19 (depends on 17) The caustic scrubbing solution of claim 17 wherein said inhibiting agent is selected from the group consisting further of isothiuronium salts, primary amines, acetophenone, dibutylamine, and iodine. ### Claim 20 (depends on 17) The caustic scrubbing solution of claim 17 wherein said inhibiting agent comprises benzoic hydrazide. ### Claim 21 (depends on 17) The caustic scrubbing solution of claim 17 wherein said inhibiting agent comprises a hydroperoxide.