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United States Patent Office Patented Feb 3,644,486 United States Patent Office Patented Feb. 22, 1972 2 acid, isobutyric acid, and preferably acetic acid. The car 3,644,486 boxylic acids are advantageously used in as concentrated PROCESS FOR THE MANUEFACTURE OF OX a form as possible, for example, acetic acid in the form of ACYLATION PRODUCTS AND OPTIONALLY HYDROXYLATON PRODUCTS OF CONDENSED glacial acetic acid. Small contents of water of up to about AROMATIC COMPOUNDS 10% of the carboxylic acids used are tolerable, however. Manfred Boldt and Hans-Jurgen Arpe, Fischbach, Taunus, It is also possible to use mixtures of the carboxylic acids and Lothar Hornig, Frankfurt am Main, Germany, as with the corresponding anhydrides in amounts of, for signors to Farbwerke Hoechst Aktiengesellschaft example, up to 30%. vormals Meister Lucius & Bruning, Frankfurt am Main, The oxygen may be introduced in an elementary form Germany O or in the form of air. No Drawing. Filed Sept. 19, 1968, Ser. No. 760,964 As noble metals the elements rhodium, iridium, plati Claims priority, application Germany, Sept. 23, 1967, num, ruthenium and advantageously palladium may be F 53,564 used in a finely divided form. As noble metal compounds Ent, CI, C07c69/14, 69/24, 69/62 there may be used salts of the noble metals with inorganic U.S. C. 260-479 R 6 Claims acids or advantageously with aliphatic Saturated carboxylic acids or complex compounds thereof with unsaturated or aromatic compounds. Examples of suitable noble metal ABSTRACT OF THE DISCLOSURE compounds are palladium chloride, palladium sulfate, Catalytic manufacture of oxacylation products and palladium acetate, the complex of benzene and palladium optionally hydroxylation products of condensed aromatic 20 acetate, and compounds of alkali metal acylates with cmpounds from condensed aromatic compounds and palladium acetate. It is also possible to use noble metal saturated aliphatic or cycloaliphatic carboxylic acids and oxides, for example palladium oxide. molecular oxygen in the presence of a noble metal of The reaction may be carried out in liquid or in the sub-group 8 of the Mendeleeff Periodic Table or com gaseous or vapour phase. High-boiling substances, for ex pounds thereof, the stable valency of this noble metal in 25 ample those having a boiling point of above 150 C., are said compounds being at most 4. advantageously reacted in the liquid or trickling phase. As reaction liquid for the liquid or trickling phase the aliphatic carboxylic acid used as starting substance or a The present invention relates to a process for the manu mixture of the reaction components may be used. facture of oxacylation products and optionally hydroxyla 30 The noble metals or the compounds thereof are used tion products of condensed aromatic compounds. in the liquid phase in a finely divided, dispersed or dis It has already been proposed to make acetic acid phenyl solved form. In the gaseous phase they are advantageously ester from benzene and acetic acid in the liquid as well used in a finely divided form supported on a carrier, for as in the gaseous phase in the presence of oxygen and a example, aluminium oxide, aluminium silicate, silica gel, noble metal of sub-group 8 of the Mendeleeff Periodic 35 carbon, zeolites, pumice, clays, feldspars or molecular Table, the stable valency of which in its compounds is at SCWCS most 4, preferably palladium. The concentration of the noble metals or the com The present invention provides a process for the manu pounds thereof may vary within wide limits and may be, facture of oxacylation products and optionally hydroxyla for example, within the range of from 0.1 to 10% by tion products of condensed aromatic compounds, which 40 weight calculated on the total liquid or the System of comprises reacting a condensed aromatic compound with carrier and catalyst when the process is carried out in the a saturated aliphatic or cycloaliphatic carboxylic acid and gaseous phase. molecular oxygen in the presence of a noble metal of sub In addition to the noble metals, transition metals, for group 8 of the Mendeleeff Periodic Table or compounds example, gold, copper, silver, iron and manganese, or thereof, the stable valency of this noble metal in said com 45 elements of Group 5 or 6 of the Mendeleeff Periodic pounds being at most 4. Table, for example, antimony, bismuth, selenium and As condensed aromatic hydrocarbons it is advantageous tellurium, may advantageously be added as promoters. to use those containing 2 or 3 aromatic rings condensed These elements may be used in concentrations of up to with one another, for example, anthracene, phenanthrene, 50 atom percent, preferably up to about 30 atom percent, fluorene, and preferably naphthalene. The hydrocarbons 50 calculated on the noble metal. By the addition of the may also contain one or more halogen atoms X or ether promoters, the yields of oxacylation products are in groups --OR as substituents, X being advantageously creased. fluorine, chlorine or bromine and R being an alkyl or The activity of the catalyst may be additionally in cycloalkyl group with 1 to 10 carbon atoms. Examples of creased by adding activators. As activators there may be such compounds are: a- and (3-chloronaphthalene, ox- and 55 used, for example, salts of a strong base with a weak acid, p-bromonaphthalene, pentachloronaphthalene, dichloro for example, carbonates or acylates of alkali or alkaline anthracene, 6-naphthylmethyl ether (nerolin), 6-naphthyl earth metals. There may also be used salts which form a 9,10-ethyl ether, 1-methoxyphenanthrene and 2-methoxy buffer system with the carboxylic acid used in a given fluorene. The substituted aromatic compounds must con case, for example, sodium phosphates or borax. There are tain at least one unsubstituted aromatic hydrocarbon 60 preferably used the alkali metal salts of the carboxylic acid atom. used, for example, the alkali metal acetates, which are As carboxylic acids there may be used saturated ali advantageously added to the reaction solution in amounts phatic or cycloaliphatic monocarboxylic acids, advan within the range of from 0.1 to 10% by weight or which tageously those containing up to 8 carbon atoms, or the may also be supported on the carrier. There may further mixtures thereof, for example, propionic acid, butyric 65 more be used neutral or basic carboxylates of the metals 3,644,486 3 4. of Group 2b, 3 or 4 of the Mendeleeff Periodic Table, EXAMPLE 2. having an atomic number of at most 72, for example 117 g. (0.74 mole) nerolin (B-naphthylmethyl ether), acylates of zinc, cadmium or of rare earths. 320 g. (5.33 moles) acetic acid and 38.24 g. (0.39 mole) During the reaction the concentration of the activator potassium acetate were heated for 6.5 hours at 118 C. in in the catalyst should remain constant. Losses which may 5 a flask provided with stirring means in a manner analo be caused by a volatility of the compounds in the course gous to Example 1, in the presence of a catalyst obtained of the reaction are advantageously compensated by adding by the impregnation of 40 g. silica gel with a nitric acid the activators, for example, to the reaction components. solution of 9.14 g. palladium acetate and 197 g. bismuth The reaction conditions used may vary within wide nitrate and subsequent reduction at 220 C. with meth limits. The reaction temperatures are advantageously O anol vapours. The work-up of the reaction mixture yielded within the range of from 50 to 300 C., preferably from 14.3 g. 1-acetoxy-2-methoxy-naphthalene. 50° C. to the boiling temperature of the reaction mixture What is claimed is: under the pressure used, and in the gaseous phase above 1. A process for the manufacture of oxacylation prod the boiling point of the reactants. The pressure is advan lucts and hydroxylation products of condensed aromatic tageously within the range of from 1 to 30, preferably hydrocarbons or substituted condensed aromatic hydro 1 to 15, atmospheres absolute. carbons, which comprises reacting said condensed aro The mixing ratios of the individual reactants may also matic hydrocarbons with a saturated aliphatic carboxylic vary within wide limits. The carboxylic acid is advan acid and molecular oxygen in liquid phase at tempera tageously used in an excess amount, preferably an amount tures within the range from 50 to 300° C. and under pres 4 times in excess, to improve the yields of oxacylation Sures within the range from 1 to 30 atmospheres absolute products. It is also possible, however, to use the con in the presence of a noble metal or a compound of a densed aromatic compound in an amount up to 4 times in noble metal wherein said noble metal is selected from the excess. Any amounts of unreacted starting materials are group consisting of ruthenium, rhodium, palladium, irid advantageously recycled. ium and platinum. By the reaction, the oxacylation products of the con 2. The process of claim 1, wherein there is additionally densed aromatic compounds used are obtained either used, as promotor, a metal of Group V of the Mendeleeff alone or in admixture with unesterified hydroxylation Periodic Table. products, the oxacyl and hydroxyl groups being directly 3. The process of claim wherein the Saturated ali bound to the nucleus. Naphthalene yields, for example, phatic carboxylic acid has up to 4 carbon atoms. 1-naphthyl acetate. The mixing ratio of the resulting 30 4. The process of claim 1 wherein the noble metal is products and the position of the newly introduced oxacyl palladium or a palladium compound. or hydroxyl group in the aromatic nucleus vary with the 5. The process of claim 1 wherein the condensed aro reaction conditions.
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