2,826,604 United States Patent Office Patented. Mar. 11, 1958 2 (130-140 C.), the decalyl acetate being recoverable from the reaction mixture by distillation of the neutralized re 2,826,604 action liquid. The recovered product was a straw-colored PREPARATION OF DECAHYDRONAPHTHYL fragrant oil, which was established to be 1-decallyl acetate. ACETATE 5 The position of the acetoxy group was determined by William E. Erner, Wilmington, Del, assignor to Houdry hydrolysis of the ester to the alcohol and subsequent Process Corporation, Wilmington, Del, a corporation conversion to decalone-1 by chromic acid-acetic acid oxi of Delaware dation. - The aceto-oxidation of Decalin can be carried out No Drawing. Application June 2, 1955 10 in the presence of oxidation catalysts of the type em Serial No. 512,853 bodied in the metal salts of the lower fatty acids. Cobalt 2 Claims. (C. 260-488) acetate proved outstanding among the metallic-soap oxi dation catalysts studied. The use of benzoyl peroxide at the start of the process has been found advantageous The present invention relates to the preparation of 1 5 in decreasing the induction period and in giving uni decahydronaphthyl alcohols and the corresponding acetic formly high yields. acid ester and ketone derivatives of Said alcohols. The ratios of Decalin - to acetic anhydride in the oper More particularly the invention is concerned with the ation of the process are not critical, but practical con production of saturated polynuclear carbocyclic com siderations favor the use of at least one-half mol of pounds of the type 20 acetic anhydride per mol of Decalin. Best operating H 2 results are obtained at a weight ratio of Decalin to acetic anhydride of between about 10:6 and 10:9. Too high a ratio of acetic anhydride, for instance in ex cess by weight of the Decalin, leads to processing diffi 25 culties in separation of the product from the reaction mix ture and also tends to produce side products such as decallyl diacetate. Too low a ratio of acetic anhydride wherein R represents hydrogen and Q represents a hy favors excessive oxidation of the Decalin charge with con droxy, or acetoxy group, or R and Q together represent sequent formation of undesired oxidation products, as a keto group. This structure may also be written 30 will hereinafter appear. The oxygen sparging rate must be carefully controlled at least from the time that the exothermic reaction be wherein D represents the decahydronaphthalene residue comes. Self-sustaining to its completion. Oxygen starva to which -OH, tion leads to the formation of undesired colored gums. 35 The oxygen addition rate during the course of a run -o-, -CH, reaches a maximum when the reaction rate is greatest O and as the reaction slows down, the oxygen rate is or -O is attached at an alpha carbon. - correspondingly decreased. With efficient oxygen sparg The invention is based on the novel discovery that ing and proper catalyst the reaction time for optimum aceto-oxidation of certain bicyclic naphthenes under con 40 results was found to be about six hours. Acetic acid can trolled conditions and in the presence of oxidation cata not be used in the process as a substitute for the an lysts, results in the formation of acetic acid esters. The hydride. obtained esters can readily be transformed by hydrolysis In the cobalt acetate catalyzed reaction, the sudden to the corresponding secondary alcohols which in turn 45 formation of a blue-black coloration throughout the are capable of being converted to their corresponding reaction mixture when the reaction begins has been ob ketones. served in all cases where high yields of decallyl acetate The invention finds particular applicability in the con were obtained. The color tends to fade during the version of a technical grade of decahydronaphthalene course of the reaction. (for example, a solvent marketed by E. I. du Pont, de 50 The process can be operated using commercial decahy Nemours of Wilmington, Delaware, under the “Decalin' dronaphthalene which contains about equal parts of the trademark) to 1-decallyl acetate, which ester is trans cis- and trans-isomers (and contains a small amount of formed by alkaline hydrolysis to 1-decally alcohol. Cata unreduced tetrahydronaphthalene as an impurity), or it lytic oxidation of the alcohol yields decalone-1. may be selectively applied to either of the isomers. The Naphthalene, in the past, has found extensive use as 55 cis-decahydronaphthalene was found to react consider a moth-repellent and as a starting material in the manu ably faster than the trans-isomer. facture of phthalic acid. Newer moth-repellent prod Disregarding polar and equatorial forms, there are four ucts and newly-developed processes for production of geometric isomers of 1-decallyl acetate: cis-cis-cis, cis phthalic anhydrides have introduced important competi trans-cis, cis-cis-trans, and cis-trans-trans. The product tion in the market demand for naphthalene. Moreover, 60 obtained from conniercial Decalin appears from its phys the present expansion of petroleum reforming has led to ical and chemical properties to be a mixture of these increased production of naphthalene and its homologues isoners. Cobalt catalysis appears to favor the forma to the extent of presenting a growing problem in their tion of the second and fourth isomers. marketing. The major product of the reaction, 1-decalyl acetate, In an extensive investigation of new uses for naph 65 has been briefly mentioned in the literature (Leroux: thalene and hydrogenated naphthalenes, attempts were Comptes Rendus, vol. 141, p. 953) but no practical proc made to convert Decalin by the Criegee rearrangement ess for its production or for that of the corresponding technique as a step in sebacic acid synthesis. These at alcohol, has heretofore been known. It is a straw colored tempts did not meet with desired success. During the mobile liquid with a characteristic odor, the mixed course of the investigation, however, it was found that O isomers obtained boiling at 110-115° C. at 3 mm. decallyl acetate was formed by oxidizing a mixture of pressure. it has a refractive index of about n 25/D of iDecalin and acetic anhydride at the reflux temperature 1.4768, and specific gravity 20/4 of 1.035. It is saponi. 2,826,604 aa s 4. fied by refluxing with aqueous-alcoholic caustic for about The results obtained by the substitution of other metal 24 hours and the resulting decalol-1 isomers are readily lic catalysts for cobalt acetate are compared in the follow isolated thereafter by distillation under reduced pressure. ing table, using a ratio in each run of 10 parts Decalin to The mixture of isomeric alcohols obtained boil at 111 4 of acetic anhydride. to 116 C. under a pressure of 2 mm. 5 1-decallyl acetate is resistant to attack by oxidizing agents such as alkaline permanganate, chromic acid, and warm nitric acid. Under strong oxidation complete de Table 2 struction of the molecule usually results. By passing Percent 1-decallyl acetate over activated alumina it is converted 10 Temp., Time, Decallyl to a mixture of octalins, acetone, water and carbon di Catalyst o C. Ers, Acetate oxide. (Based on Oxidation of the alcohol, decalol-1, can be more readily Dry Oil) controlled. Thus, mild oxidation of the alcohol mixture Cobalt Acetate------------------------- 30 6.5 23.7 yields decalone-1. By nitric acid oxidation of decalol-1 5 Cobalt Naphthenate- 30-40 44 14.1 Iron Phthalocyanine 30-40 24 2, 3 there was obtained a mixture of products composed Mn Naphthenate-- 130-40 20 2.0 chiefly of dicarboxy acids including 2,7-dehydrosebacic Red Lead (Pb3O4). 25-40 23.75 9. acid (40%), glutaric acid (25%) and adipic acid (4%). Ni Naphthenate------------------------ 130-140 44 1. EXAMPLE 20 The reaction was carried out in a resin kettle equipped The metallic salt can be introduced into the reaction with a centrifugal stirrer, a thermowell, and a fritted mixture as a finely divided powder or it may be dispersed glass sparging tube for introduction of oxygen gas. A in either reactant. Cobalt shows the best activity par reflux condenser connected to the kettle led to an absorp 2 5 ticular in the form of its acetate. While the presence of tion train for removal of carbon dioxide, carbon mon benzoyl peroxide is not absolutely necessary to the pro oxide and water. The kettle was charged with 875 parts gress of the reaction, it is advantageously employed at the by weight of commercial Decalin and 525 parts acetic start of the reaction, since it reduces the induction period anhydride (of 90-95% purity). and leads to uniform results and constantly high yields. The mixture was stirred, and 3 parts by weight of ben Zoyl peroxide was sprinkled in through the thermowell EXAMPLE I neck, followed by 22 parts of finely ground cobalt acetate Conversion of the decallyl acetate to the alcohol was ef (=3 parts Co). The thermowell was then set in place fected by adding a Soiution (about 190 g/l.) of caustic and oxygen Sparged through the stirred mixture at the soda in 80% ethyl alcohol to the decallyl acetate using 1 rate of .0035 cu. ft./min. per 1.4 kg. of the Decalin plus mol caustic (NaOH) per 0.9 mol decallyl acetate and acetic anhydride. The external heating mantle Sur heating under reflux for 22 hours. After cooling the rounding the kettle was then set in operation and in about reaction mixture, the supernatant liquid decanted from 20 minutes the temperature of the mixture reached 88° the residue was fractionated under reduced pressure ob C.