TITLE:
Regioselective Direct Carboxylation of 2-Naphthol with Supercritical CO2 in the Presence of K2CO3
AUTHORS:
Shigeki Furukawa, Kensuke Otokawa, Osamu Sasaki, Ken Nakayasu, Tatsuaki Yamaguchi
KEYWORDS:
Supercritical CO2; CO2 Utilization; Kolbe-Schmitt Reaction; Carboxylation; 2-Naphthol; Potassium Carbonate; 2-Hydroxynaphthalene-6-carboxylic Acid; DFT Calculation
JOURNAL NAME:
International Journal of Organic Chemistry,
Vol.3 No.3,
September
24,
2013
ABSTRACT: A direct regioselective preparation of 2-hydroxynaphthalene-6-carboxylic acid, a useful industrial intermediate of aro-matic polyester from 2-naphthol was conducted by use of excess amount of K2CO3 (10-fold molar to 2-naphthol) under supercritical CO2 at 10 MPa and 473 K. The obtained yield under this condition was ca. 20 mol% to 2-naphthol. The further investigations may provide an alternative process to the conventional Kolbe-Schmitt reaction, because of no use of strong alkali and recoverability of K2CO3. Theoretical explanation about the regioselectivity was achieved by means of DFT calculations.