Method of making chlorobenzenes
AssigneeOccidental Chemical Corporation
InventorRamesh Krishnamurti
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Abstract
Disclosed is a method of making a chlorobenzene having the general formulas ##STR1## where X is Cl or F, and X' is X or CF.sub.3. A compound having the formula ##STR2## is sulfonated using at least 2 moles per mole of said compound of a sulfonating agent selected from the group consisting of sulfuric acid, chlorosulfonic acid, and mixtures thereof, to produce a sulfonated compound. The sulfonated compound is chlorodesulfonated to produce a chlorobenzene, such as 1,2,4-trichlorobenzene. Preferably, the starting material is ortho-dichlorobenzene.
Claims20
A method of making a chlorobenzene having the general formula ##STR4## where X is C or F, and X' is X or CF.sub.3 comprising (A) heating a compound having the formula ##STR5## with at least 2 moles per mole of said compound of a sulfonating agent selected from the group consisting of sulfuric acid, chlorosulfonic acid, and mixtures thereof to produce a sulfonated compound;
- and
- (B) heating said sulfonated compound at about 50.degree. to about 250.degree. C. in the presence of at least a catalytic amount of gaseous chlorine to produce said chlorobenzene.
A method of making 1,2,4-trichlorobenzene comprising
- (A) reacting 1,2-dichlorobenzene with sulfuric acid at a molar ratio of about 2.5 to about 3 in the presence of a catalyst selected from the group consisting of phosphomolybic acid, phosphotunqstic acid, and mixtures thereof at about 180.degree. to about 205.degree. C. to produce 3,4-dichlorophenylsulfone;
- and
- (B) reacting said 3,4-dichlorophenylsulfone with at least 1.1 moles of chlorine gas per mole of said 3,4-dichlorophenylsulfone at about 50.degree. to about 250.degree. C.
A method of making 1,2,4-trichlorobenzene comprising
- (A) reacting 1,2-dichlorobenzene with chlorosulfonic acid at a molar ratio of about 2.5 to about 3 at about 180.degree. to about 205.degree. C. to produce a mixture of 3,4-dichlorobenzenesulfonyl chloride and 3,4-dichlorophenylsulfone;
- and
- (B) reacting said mixture with at least a catalytic amount of chlorine gas at about 50.degree. to about 250.degree. C.
Dependencies are inferred from the claim text.