Europiisches Patentamt European Patent Office © Publication number: 0 049 616 Office europeen des brevets A1 EUROPEAN PATENT APPLICATION © Application number: 81304567.1 © int. ci.3: C 07 C 69/88 C 07 C 67/36 © Date of filing: 02.10.81 © Priority: 06.10.80 US 194201 © Applicant: CELANESE CORPORATION 1211 Avenue Of The Americas New York New York 10036IUS) © Date of publication of application: 14.04.82 Bulletin 82/15 © Inventor: McGinnes, James L 236 Raritan Avenue © Designated Contracting States: Middlesex New Jersey(US) BE DE FR GB IT NL © Inventor: Conciatori, Anthony B. 27. Orchard Road Chatham New Jersey(US) @ Representative: De Minvielle-Devaux, Ian Benedict Peter et al, CARPMAELS & RANSFORD 43, Bloomsbury Square London WC1 A 2RA(GB) © Preparation of hydroxy aromatic carboxylic acids and ester derivatives thereof. A process for preparing hydroxy aromatic carboxylic acids, or the ester derivatives thereof, comprises carbonylat- ing a hydroxy aromatic halide in the presence of a reactive alcohol solvent and a catalytic amount of a Group VIII metal catalyst. The process has particular applicability to the preparation of 6-hydroxy-2-naphthoic acid from 6-bromo-2- naphthol, which can be easily prepared from β-naphthol, a readily available and inexpensive starting material. This invention relates to a novel process for pre- paring hydroxy aromatic carboxylic acids or the corresponding ester derivatives thereof. This invention relates particular- ly to a novel process for the preparation of esters of hydroxy aromatic carboxylic acids such as 6-hydroxy-2- naphthoic acid by the carbonylation of a hydroxy aromatic halide, followed if desired by conversion of the esters to the acids. Hydroxy aromatic carboxylic acids and their application in various technological areas such as dyes and pigments are well known in the art. The technological applications of hydroxy aromatic acids are also continuing to expand. An example of one hydroxy carboxylic acid in particular whose technological applicability has resulted in an increased demand for the compound is 6-hydroxy-2-naphthoic acid. The increased demand for such hydroxy aromatic acids has also intensified the search for more commercially acceptable methods of synthesising said compounds. The formation of aromatic carboxylic acids or functional derivatives thereof by reactions involving the carbonylation of aromatic systems is well recognised in the art. One-type of reaction between an aromatic system and carbon monoxide involves the insertion of a carbonyl group into a molecule between the aromatic moiety and a functional moiety attached thereto. For example, U.S. Patent No. 3,452,090 discloses a process for the production of aroyl halides in which an aryl halide is reacted with carbon monoxide in the presence of a platinum, palladium, ruthenium, rhodium, osmium or iridium catalyst and an inert solvent. The reaction takes place at the site of the halogen resulting in the insertion of a carboxyl group into the molecule thus to form the aroyl halide. The said Patent discloses that substituents other than the halo- gen groups can be attached to the aromatic system as long as the substituents are inert and are not affected by the reaction. Examples of such inert substituents are the alkyl groups and nitro groups. Hydroxy groups are not disclosed, however, as possible substittrents. A. Schoenberg et :al, in the Journal of OrganicChemistry, Volume 39, pp. 3318-3326 (1974), disclose the reaction of aryl and vinylic bromides and iodides with carbon monoxide and an alcohol in the presence of a tertiary amine and a catalytic amount of a palladium-triphenylphosphine complex to form esters. With respect to substituent effects, the carbonylation was reported to proceed most rapidly with electron withdrawing substituents on the aromatic ring, in contra-distinction to electron.. donating substituents which produced appreciably decreased reaction rates. As well, the brominated naphthalenes were reported as being significantly less reactive than other aryl bromides. In view of these reports, the carbonylation of a hydroxy aromatic halide, and in particular a brominated naphthol, to obtain a hydroxy aromatic acid such as 6-hydroxy-2-naphthoic acid, or the corresponding ester thereof, would appear to have little chance, if any, of success. Indeed, no attempt to carbon- ylate a hydroxy aryl bromide or iodide was reported. Stille et al, in the Journal of' Urganic Chemistry, Volume 40, pp. 532-534 (1975), and Hidai et al, in the Bulletin of the Chemical society of Japan, Volume 48, pp. 2075-2077 (1977), disclose the reaction of organic halides in the presence of an alcohol and palladium complex catalyst. However, the reaction of hydroxy organic halides is not reported. U.S. Patents Nos. 3,769,324 and 3,769,326 disclose the carbonylation of hydroxy aromatic compounds. However, the carbonylation reaction takes place at the site of the hydroxy group. More specifically, carboxylic acids and their esters can be obtained by reacting aromatic alcohols, and the ester, ether and halide derivatives thereof, with carbon monoxide in the presence of an iridium, osmium or ruthenium catalyst system. The reaction can take place under a broad range of temperature and pressure conditions, e.g., a temperature in the range of 50-300°C. and a carbon monoxide partial pressure in the range of 1-15,000 psi, with the reac- tion involving the insertion of a carbonyl between the hydroxy, ester ether or halide moiety and the remainder of the molecule. For example, benzoic acid is prepared from a phenol feedstock and phenyl acetic acid from a benzoyl alcohol feedstock. U.S. Patent No. 2,565,463 discloses a process for the carbonylation of organic halides wherein an aryl halide is reacted with carbon monoxide in the presence of a carboxylic acid modifier, e.g., an alkanoic acid such as acetic, prop- ionic, succinic, adipic, stearic or palmitic acid. The pres- ence of the carboxylic acid modifier results in the formation of an anhydride product which can then be readily converted to the acid upon the subsequent addition of water. U.S. Patent No. 3,009,951 discloses a process for carbonylating an aryl halide to produce carboxylic acids or their corresponding esters and salts. The ester of an arom- atic carboxylic acid is obtained upon conducting the reaction in the presence of an alcohol. U.S. Patent No. 4,016,194 discloses the preparation of phenylenediacetate diesters by the catalytic insertion of carbon monoxide into the carbon-chlorine bonds of @,@'- dichloroxylenes by the reaction of said xylenes in the presence of alcohols. Two-phase reaction mediums have also been employed successfully in preparing carboxylic acids via the carbon- ylation of an aromatic system. For example, U.S. Patent No. 4,034,004 discloses the reaction of an organic halide with carbon monoxide with said reaction being conducted in an organic/aqueous biphase system. U.S. Patent No. 3,700,729 discloses reacting an organic aromatic compound, which can be a phenol or naphthol, with carbon monoxide in the presence of a substantially anhydrous organic liquid reaction medium which contains a catalyst and is inert to said reactants and catalyst. However, the reaction proceeds purely as an oxidation reaction thus to produce an oxidatively carbonylated aromatic compound which can be subsequentlyhydrolysed to form the aromatic acid. No insertion of CO per se is involved. Although the prior art has recognised, as evidenced by the afore-mentioned Patents, many different processes involving various reactants, reaction media, catalysts and reaction parameters for the formation of aromatic carboxylic acids by carbonylating an aromatic system with insertion of a carbonyl group, such a reaction has not been employed to produce hydroxy aromatic carboxylic acids, and more partic- ularly, hydroxy naphthoic acids. Instead, hydroxy aromatic carboxylic acids such as the naphthoic acids, and in partic- ular, 6-hydroxy-2-naphthoic acid, have typically been prepared by other methods. These methods, however, due to the disadvantages associated with each, have limited the commercial application of hydroxy aromatic carboxylic acids. For instance, one of the first reactions to form the specific hydroxy aromatic carboxylic acid, 6-hydroxy-2- naphthoic acid, was reported in 1.923 by Butler and Royle in the Journal of the Chemical Society, Volume 123, p. 1649. The synthesis involves initially producing 2-cyano-6-naphthalene sulfonic acid by diazotising Bronners' Acid (2-amino-6-naph- thalene sulfonic acid) with sodium nitrite in the presence of hydrochloric acid and then treating with cuprous cyanide in accordance with the well known Sandmeyer Reaction. The 2-cyano-6-naphthalene sulfonic acid is then hydrolysed with potassium hydroxide to the potassium salt of 2-carboxy-6- naphthalene sulfonic acid, which is then fused with potassium hydroxide at 260-280°C., or treated with a 25% aqueous solution of potassium hydroxide at 260°C. in 30 atmospheres of pressure, thereby to produce the 6-hydroxy-2-naphthoic - acid. The overall yield from the initial starting material of Bronners' Acid is about 50%, which is an attractive reaction yield for commercialisation purposes. One of the disadvantages associated with the Butler et al synthesis stems from the fact that Bronners' Acid is a carcinogen and/or generally contains the potent carcinogen β-naphthyl amine as an impurity. Moreover, hydrogen cyanide is evolved during the Sandmeyer Reaction. Thus, to commercialise the afore-going process would be extremely costly due to the necessary provision of safeguards for the handling of the Bronners' Acid and the protection of the workers against the hydrogen cyanide evolution. Another process for forming 6-hydroxy-2-naphthoic acid is a two-step synthesis route discussed by Cason in the Journal of the American Chemical Society, Volume 63, page 828 (1941). In the first step of this process, potassium cyanide or potassium ferricyanide is fused with Bronners' Acid in order to replace the sulfonic acid grouping with a cyano group.