3,163,673 United States Patent Office - Patented Dec. 29, 1964 2. 3,163,673 O METHOD OF PREPARNG DBASIC ACDS FROM NAPHTHALENE AND PRODUCTS OBTANED s Giampaolo Chiusoli, Novara, and Francesco Minisci and Adolfo Qsilico, Milan, Italy, assignors to Montecatiri Societa Generale per industria Mineraria e Chimica, a corporation of Italy No Drawing. Fied May 13, 1957, Ser. No. 658,525 (III) Claims priority, applicationa tally May 15, 1956 -a-3 m 3 Claims. (C. 260-537) 10 H o ( This invention relates to a method of preparing dibasic acids, particularly delta-keto-sebacic acid and delta-hy droxy-sebacic acid, by subjecting naphthalene to the chem () (II) ical action of air and oxygen. The products obtained OB thereby were found to represent important starting ma 15 - HO terials for making polymers, delta-hydroxy-sebacic acid {- being particularly suitable for preparing polyamid poly mers and co-polymers. (XI) (X) The process according to the present invention is based a-Decalone, prepared in this manner, both in the cis upon the following reactions: 20 and trans-form and in mixtures thereof, can be oxidized - O by means of potassium permaganate or chromium tri - oxide to yield delta-keto-sebacic acid (V). O O It is the principal object of the present invention to mm.9 H prepare dibasic acids, particularly delta-keto- and delta 25 hydroxy-sebacic acid from naphthalene by means of a new process. (I) (). (III) It is another object of the invention to provide in said CooH dibasic acids valuable starting materials for the prepara ScooH H 30 tion of polymerization and co-polymerization products. --9 It is still another object to provide such polymerization C and co-polymerization products. These and other objects and advantages will appear ... O more clearly from the herein-following detailed descrip (V) tion and examples. COOH 35 According to the present invention, decalone is oxidized continuously or batch-wise under atmospheric conditions, - HOOC-(CH2)6-COOH but preferably under pressure, by means of air or oxy gen which may be diluted with nitrogen, to cyclo-hex H. ... (VII) 40 anone-butyric acid (IV), i.e. ?y-(2-keto-cyclohexyl) butyric (WI) acid, and to delta-keto-sebacic acid (V), in a liquid phase reaction and, if desired, in the presence of oxidation. It is known that naphthalene (I) can be converted into catalysts such as peroxides, cobalt-, iron-, manganese-, or tetralin (VIII) and decalin (II) by means of hydrogena chromium-salts and the like. The temperature is kept at tion. Starting with tetralin, tetralone (IX) can be ob 70 to 170° C., but preferably between 80 to 130° C. and tained, by means of oxidation with air (Balaceanu, Acts the oxygen pressure or oxygen partial pressure at 5 to 25 of the 4th Petroleum Congress, 1955, IV/B). From the atmospheres. latter, c-decalone (III) is obtained by selective reduction The process is preferably carried out in two stages, with hydrogen: because the oxidation of decalone yields primarily cyclo O ... O 50 hexanone-butyric acid. - - - - . After this acid has been removed from the mixture of ... H acids resulting from the oxidation, further conversion to --> . --> keto-sebacic acid takes place under the same reaction conditions. The latter can be isolated from the other 55 acids, by washing with chloroform or other solvents in (I) (VIII) (I X) (III) which it does not dissolve. The oxidation is preferably carried out in an aqueous medium, optionally in the pres Decalone (III) can be also prepared from decalin ence of solvents, e.g. acetic acid, and of emulsifying. (II) by direct oxidation with air. In such a case, a sub agents. Cyclo-hexanone-butyric acid can be further oxi stantial amount of the reaction product consists of 9-oxy- 60 dized by means of hydrogen peroxide, at room tempera decalin (X). ... - . ture. A peroxide, which can be decomposed by means cilityMoreover, at which it9-oxy-decalin has been found can bethat, dehydrated because (especiallyof the fa of alkalies or acids, is obtained. : . when starting from the trans-form of the decalin), it is delta-keto-sebacic acid can be used as a monomer in possible to return the resulting octalin (XI) to the polymerization and co-polymerization processes. Partic naphthalene hydrogenation stage so that, as the only prod 65 ularly upon condensation with hexamethylene diamine a uct of the oxidation, decalone is obtained. salt is obtained which is able to undergo polymerization so as to yield a plastic material. 3,163,673 3 4. Upon reduction with hydrogen under pressure and in form whereby delta-keto-sabacic acid remains un-dis the presence of catalysts, keto-sebacic acid is converted solved. From 1 kg. of crude acids, about 0.25 kg. of into hydroxy-sebacic acid (VI) keto-sebacic acid is obtained. HOOC-(CH2)4-CHOH-(CH)-COOH Example 7 The latter is a white solid, which melts at 103° C. and One kg. of keto-sebacic acid, in an alkaline solution, forms a lacetone is reduced with hydrogen and Raney nickel at 130 C. Hooc-(CH2-H-(gH), under a pressure of 100 atmospheres. 0.95 kg. of delta -CO hydroxy-sebacic acid are obtained. from which it can be restored by means of an alkali. O Example 8 The acid is soluble in water, insoluble into chloroform and slightly soluble in ethyl ether. One kg. of keto-sebacic acid, in alkaline solution, is The salt formation and polycondensation are carried reduced under the same conditions as specified in Ex out according to known processes for preparing poly ample 7. Afterwards, the temperature is increased to amides. The resulting polymer shows hydrophilic char 5 270° C. and the pressure to 220 atmospheres. After 8 acteristics. hours, 0.15 kg. of sebacic acid and 0.75 kg. of hydroxy The same result is attained by forming a salt between sebacic acid are obtained. the lactone of hydroxy-sebacic acid and hexamethylene Example 9 diamine and polymerizing the resulting salt. Hydroxy-sebacic acid and hexamethylene-diamine are After reduction to delta-hydroxy-sebacic acid, delta 20 dissolved, at an equimolecular ratio, in absolute alcohol. keto-sebacic acid can be further hydrogenated to sebacic From this mixture, hexamethylene-diamine-hydroxy acid, at temperatures above 200° C., preferably at a sebacate (M.P. 150° C.) crystallizes. This salt is heated temperature ranging from 250 to 300° C. Previous reduc to 200° C. in an autoclave, in the presence of water; the tion to hydroxy-sebacic acid is necessary, in order to avoid temperature is gradually increased and the pressure is intra-molecular condensation reactions of the carbonyl 25 maintained at a constant value by venting. The mixture group. is kept at 250° C. for 15 minutes; then the pressure is Example 1 slowly released over the period of one hour. Naphthalene is hydrogenated to yield decalin in the The product is kept one hour longer at 250 C. and is known manner. The latter is oxidized in a stream of then discharged. It has a melting point of about 175 C. oxygen or air or oxygen diluted with nitrogen and in the 30 Alternatively, the salt obtained upon condensing hexa presence of one of the previously mentioned catalysts. methylene-diamine with the lactone of hydroxy-sebacic The resulting mixture, consisting of 9-oxy-decalin, acid is polymerized in a similar manner. and decalone, is distilled. Together with un-converted We claim: decalin and ox-decalone, 9-oxy-decalin is obtained which, 1. A process for making delta-keto-sebacic acid com by means of dehydration, is converted into octalin, which prising treating gamma-(2-ketocyclohexyl) butyric acid is then returned to the stage at which naphthalene is with hydrogen peroxide in alkaline solution and decom hydrogenated to decalin. posing the resulting peroxide with an acid. 2. A process of making delta-keto-sebacic acid com Example 2 prising treating gamma-(2-ketocyclohexyl) butyric acid One kg. of ox-decalone in the trans form is oxidized by 40 with hydrogen peroxide in alkaline solution and decom means of air at 100° C. and under a pressure of 100 posing the resulting peroxide with sulfuric acid. atmospheres. The oxidation proceeds until about 30 per 3. A process of making delta-keto-sebacic acid com cent of the decalone is converted. 320 g. of acids, con prising treating gamma-(2-ketocyclohexyl) butyric acid taining 120 g. of cyclo-hexanone-butyric acid, are ob with hydrogen peroxide and alkaline solution and decom tained. 45 Example 3 posing the resulting peroxide with an alkali. One kg. of trans co-decalone, emulsified in 4 kg. of References Cited in the file of this patent water, is oxidized by means of air and in the presence of cobalt naphthenate, in an autoclave, at a temperature of UNITED STATES PATENTS 90° C., and under a pressure of 50 atmospheres. The 50 991,720 Hofmann et al. ---------- May 9, 1911 oxidation is permitted to proceed until 4 of the decalone 2,176,074 Jacobson -------------- Oct. 17, 1939 is oxidized. The acid portion (250 g.) contains 125 g. 2,279,745 Stevenson -------------- Apr. 14, 1942 of cyclo-hexanone-butyric acid and 12 g. of keto-sebacic 2,338,114 Isbell ------------------- Jan. 4, 1944 acid. - 2,377,246 Kyrides ---------------- May 29, 1945 Example 4 55 2,388,813 Allen et al. ------------ Nov. 13, 1945 One kg. of cyclo-hexanone-butyric acid is oxidized with 2,499,797 Theobald --------------- Mar. 7, 1950 air for 6 hours, at 100° C., in the presence of water and 2,594,355 Schwenk et al. ---------- Apr. 29, 1952 cobalt toluate, under 100 atmospheres pressure.