Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1986-07-01
1988-10-25
Killos, Paul J.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
562423, 562424, C07L 5115
Patent
active
047805676
DESCRIPTION:
BRIEF SUMMARY
FIELD OF TECHNOLOGY
This invention relates to a process for selectively producing aromatic hydroxycarboxylic acids, which comprises liquefying an alkali metal salt of an aromatic hydroxy compound with an added aromatic hydroxy compound, followed by reaction with carbon dioxide in a liquid-liquid mixture with a medium.
BACKGROUND TECHNOLOGY
Aromatic hydroxycarboxylic acids, particularly p-hydroxybenzoic acid, salicylic acid, 2-hydroxy-3-naphthoic acid, etc., have long been known for their usefulness as raw materials for the production of antiseptic and antifungal agents, pharmaceuticals, dyestuffs, pigments and the like, and in recent years, have furthermore acquired increasingly greater importance not only as starting compounds for the synthesis of agricultural chemicals, color developing agents for thermosensitive recording paper, etc. but also as monomers for aromatic polyesters.
These aromatic hydroxycarboxylic acids have conventionally been produced by means of the so-called Kolbe-Schmitt process involving a vapor-solid phase reaction of an alkali metal salt of aromatic hydroxy compound with carbon dioxide. Lately, one of the present inventors has improved the said vapor-solid phase reaction process into the liquid-solid phase reaction process making use of a suspension phase, and thus, there has been established a process which permits an industrial-scale, mass-production of such aromatic hydroxycarboxylic acids [refer to the specification of Patent Application No. 39281/1983 (Laid-Open Patent Publication No. 164751/1984)].
DISCLOSURE OF THE INVENTION
The present inventors, with a specific view to further improving the process, carried out repeated research, and found that diaryl or triaryl based polycyclic aromatic hydrocarbons remaining liquid at ambient temperature and showing a boiling point of not less than 250.degree. C. can produce excellent effects under conditions of an added aromatic hydroxy compound. The finding has led to the completion of this invention.
This invention is directed to a process for selectively producing aromatic hydroxycarboxylic acids, characterized in that the said process comprises allowing a liquid mixture consisting of a polycyclic aromatic hydrocarbon, alkali metal salt of an aromatic hydroxy compound and free aromatic hydroxy compound to undergo reaction with carbon dioxide.
The present invention can achieve the following effects:
(1) The media of this invention can suspend thoroughly alkali metal salts of aromatic hydroxy compounds, which permits the complete dehydration of such alkali metal salts of aromatic hydroxy compounds to be performed promptly and at relatively low temperatures. Consequently, therecan be easily obtained anhydrous alkali metal salts of aromatic hydroxy compounds as a raw material, which, when admixed with aromatic hydroxy compounds and the reaction medium and subjected to a reaction with carbon dioxide, contribute to outstandingly improved yields of the objective compound to be obtained in such a reaction.
(2) A mixture consisting of an anhydrous alkali metal salt of aromatic hydroxy compound, aromatic hydroxy compound and a reaction medium has their components all kept in the liquid form and suspended thoroughly and uniformly under reaction conditions, and can be transported in a quantitative manner, which secures the constant reaction yield in the continuous production process.
(3) The improvement of both yield and selectivity is of utmost importance in the Kolbe-Schmitt reaction, where the production of isomers is always involved and basically inevitable owing to the principle of orientation in the aromatic substitution reaction. In the conventional Kolbe-Schmitt reaction processes, the production of isomers takes place, in spite of the reaction conditions, inclusive of temperature and pressure, being optiomally set to minimize the isomer production. However, this invention constitutes a process which keeps the starting material system in the liquid form under reaction conditions and consequently suppresses markedly the production
REFERENCES:
patent: 2132356 (1938-10-01), Lecher et al.
patent: 2132357 (1938-10-01), Lecher et al.
patent: 4239913 (1980-12-01), Ueno et al.
patent: 4297508 (1981-10-01), Maegawa et al.
Alan S. Lindsey and Harold Jeskey, "The Kolbe-Schmitt Reaction", Chemical Reviews, vol. 57, No. 4, pp. 583-620 (Aug. 1957).
Kanagae Toshiharu
Kishimoto Mitsuyuki
Ueno Ryuzo
Kabushiki Kaisha Ueno Seiyaku Oyo Kenkuyo
Killos Paul J.
LandOfFree
Process for producing aromatic hydroxycarboxylic acids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing aromatic hydroxycarboxylic acids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing aromatic hydroxycarboxylic acids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2270431