Process for the preparation of esters of stilbenedicarboxylic acid
AssigneeEastman Chemical Company
InventorRichard H. S. Wang
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Abstract
Disclosed is a process for the preparation of 4,4'-stilbenedicarboxylate esters by a 3-step process utilizing p-toluic acid, an alkyl p-formylbenzoate and a trialkyl phosphite. The steps comprise (1) preparing p-(chloromethyl)benzoic acid by chlorinating p-toluic acid with sulfuryl chloride in the presence of a free radical initiator and chlorobenzene or dichlorobenzene; (2) contacting the p-(chloromethyl)benzoic acid of step (1) with a trialkyl phosphite to obtain a phosphonate compound; and (3) contacting the phosphonate ester compound of step (2) with an alkyl p-formylbenzoate in the presence of an alkali metal alkoxide and an inert solvent to obtain the dialkyl 4,4'-stilbenedicarboxylate.
Claims9
Process for the preparation of a dialkyl 4,4'-stilbenedicarboxylate having the formula ##STR4## by the steps comprising:
- (1) preparing p-(chloromethyl)benzoic acid by chlorinating p-toluic acid with sulfuryl chloride in the presence of a free radical initiator and chlorobenzene or dichlorobenzene;
- (2) contacting the p-(chloromethyl)benzoic acid of step (1) with a trialkyl phosphite having the formula (R.sup.2 O).sub.3 P to obtain a phosphonate compound having the formula:
- ##STR5## and (1) contacting the phosphonate ester compound of step (3) with an alkyl p-formylbenzoate in the presence of an alkali metal alkoxide and an inert solvent to obtain the dialkyl 4,4'-stilbenedicarboxylate;
- wherein R.sup.1 is alkyl of 1 to 6 carbon atoms and R.sup.2 is alkyl of 2 to 6 carbon atoms.
Process for the preparation of a dialkyl 4,4'-stilbenedicarboxylate having the formula ##STR6## by the steps comprising:
- (1) preparing p-(chloromethyl)benzoic acid by chlorinating p-toluic acid with sulfuryl chloride at a temperature of about 70.degree. to 100.degree. C. using about 1.1 to 2 moles of sulfuryl chloride per mole of toluic acid, a free radical initiator selected from aroyl peroxides and azo compounds, and a solvent selected from chlorobenzene, dichlorobenzene or a mixture thereof in a solvent:p-toluic acid weight ratio in the range of about 1:1 to 5:1;
- (2) contacting the p-(chloromethyl)benzoic acid of step (1) with triethyl phosphite at a temperature of 140.degree. to 180.degree. C. to obtain a phosphonate compound having the formula:
- ##STR7## wherein the mole ratio of triethyl phosphite to p-(chloromethyl)benzoic acid is in the range of about 2:1 to 10:1;
- and
- (3) contacting the phosphonate ester compound of step (2) with an methyl p-formylbenzoate at a temperature of about 25.degree. to 35.degree. C. in the presence of an alkali metal hydroxide using about 1.2 to 2.0 moles alkali metal hydroxide per mole of methyl p-formylbenzoate and an inert, polar, aprotic solvent to obtain the dialkyl 4,4'-stilbenedicarboxylate;
- wherein R.sup.1 is methyl and R.sup.2 is methyl or ethyl.
Process for the preparation of p-(chloromethyl)benzoic acid which comprises chlorinating p-toluic acid with sulfuryl chloride in the presence of a free radical initiator and in a solvent comprising chlorobenzene, dichlorobenzene, or a mixture thereof.
Dependencies are inferred from the claim text.