Preparation method of 4-aminomethylbenzoic acid
View Patent ↗The present invention relates to a preparation method of 4-aminomethylbenzoic acid comprising the following steps: preparing 4-carboxylbenzaldehyde or an alkyl ester thereof (methyl 4-formyl benzoate); reacting the 4-carboxylbenzaldehyde or an alkyl ester thereof (methyl 4-formyl benzoate) with hydroxyamine to oximate the same; and contact reducing 4-carboxylbenzaldehyde oxime or an alkyl ester oxime thereof obtained by the oximation, through hydrogen in a sodium hydroxide aqueous solution. Since methyl 4-hydroxyiminomethylbenzoate is reacted as a raw material in the presence of an alkali, hydrogen of a relatively low pressure can be used and a purification process is also simple, thereby enabling preparation of 4-aminomethylbenzoic acid with a low cost and high yield.
1. A method of preparing 4-aminomethylbenzoic acid, comprising:
preparing methyl 4-formylbenzoate;
reacting the methyl 4-formylbenzoate with hydroxylamine, thus producing methyl 4-hydroxyiminomethylbenzoate; and
subjecting the methyl 4-hydroxyiminomethylbenzoate to catalytic reduction using hydrogen in a sodium hydroxide aqueous solution, wherein the catalytic reduction is performed at a stirring rate of at least 1200 rpm.
2. The method of claim 1 , wherein the catalytic reduction is performed using a catalyst.
3. The method of claim 2 , wherein the catalyst includes any one selected from among palladium, platinum, rhodium, iridium, and nickel.
4. The method of claim 2 , wherein the catalyst is a Pd/C catalyst in which an amount of Pd is 1-15 wt % based on a total weight of the catalyst.
5. The method of claim 1 , wherein the catalytic reduction is performed at a pressure of 1-15 atm and at a temperature of 30-50° C.
6. The method of claim 1 , further comprising concentrating and filtering a product, after carrying out the catalytic reduction.
7. The method of claim 1 , wherein the stirring rate is 1200-2000 rpm.
8. The method of claim 1 , wherein the methyl 4-formylbenzoate is contained in an amount of 8-18 wt % based on a total weight of reactants.
9. The method of claim 1 , wherein the sodium hydroxide aqueous solution is added in an amount 0.2-1.0 times a weight of the methyl 4-hydroxyiminomethylbenzoate.