公开(公告)号：DK248375A

公开(公告)日：1975-12-05

申请号：DK248375

申请日：1975-06-03

Applicant: HOECHST AG

Inventor： BACHMANN W ,  GNABS C ,  JANECKA K ,  MUNDLOS E ,  PAPENFUHS T ,  WAESE G

IPC: C07C65/11 ,  C07C51/00 ,  C07C51/15 ,  C07C67/00 ,  C07C

公开(公告)号：DK248275A

公开(公告)日：1975-12-05

申请号：DK248275

申请日：1975-06-03

Applicant: HOECHST AG

Inventor： BACHMANN W ,  GNABS C ,  JANECKA K ,  MUNDLOS E ,  PAPENFUHS T ,  WAESE G

IPC: C07C65/11 ,  C07C51/00 ,  C07C51/43 ,  C07C67/00 ,  C07C

Abstract: An improved process for isolating 2-hydroxynaphthalenecarboxylic acids from reaction mixtures of the alkali metal salts of the 2-hydroxynaphthalene with carbon dioxide had been found which comprises diluting with water the reaction mixture which contains the di-alkali metal salt of 2-hydroxynaphthalenecarboxylic acid and 2-hydroxynaphthalene, while keeping the mixture at a temperature of at least 80 DEG C, then adjusting the pH-value to about 6 to 7 by means of aqueous mineral acid, separating the lower phase at at least 80 DEG C, cooling the upper phase to about 15 DEG to 25 DEG C, separating the 2-hydroxynaphthalene, then adjusting the pH-value to about 1 to 2 by means of aqueous mineral acid and isolating the separated 2-hydroxynaphthalenecarboxylic acid. By this novel process, work intensive operations, expensive technical apparatuses which are suspectible to repairs, solvents which do not participate directly in the reaction and therewith complicated regenerations, as known from the present art, are completely avoided. It permits clear and very easy separation of the reaction products at only one and the same stage in the process and allows in advantageous manner continuous operation.