3,655,769 United States Patent Office Patented Apr. 11, 1972 2 or alkyl metaborate oxidation directors and not require 3,655,769 the prior removal of the oxidation inhibiting cyclic hydro OX DATION OF n-PARAFFINS b carbon. Matthew A. McMahon, Wappingers Falls, N.Y., assignor SUMMARY OF THE INVENTION to Texaco Inc., New York, N.Y. No Drawing. Filed Sept. 25, 1967, Ser. No. 670,374 I have discovered and this constitutes my invention an Int, CI, C07c45/02, 31/00 O n-paraffin oxidation procedure which employs the afore U.S. C. 260-597 7 Claims mentioned boron oxidation directors and which does not require the pretreatment of the n-paraffin reactant to re move oxidation inhibiting cyclic hydrocarbons. More ABSTRACT OF THE DISCLOSURE 10 specifically, I have discovered a method of oxidizing n A method of oxidizing n-paraffins of between about 6 paraffin having an ultraviolet light absorbancy at 260 and 20 carbons having an ultraviolet light absorbancy of 280 mu of at least about 1 and up to 560 or more to at least about 1 at 260-280 mu to produce oxidates rich produce an oxygenated product consisting primarily of in secondary alkanols comprising contacting said n-paraf Secondary alkanol and aliphtaic ketones utilizing an oxi fin with oxygen in the presence of between about .001 and 5 dation director favoring the manufacture of secondary 5 wt. percent of a peroxide selected from the group con alcohols in which the inhibiting effect of the 260-280 mu, sisting of t-butyl hydroperoxide and di-t-butyl peroxide cyclic hydrocarbon impurities in the n-paraffin reactant in and between about 1 and 15 wt. percent of a boron com combination with such oxidation director is effectively pound selected from the group consisting of boric oxide, 20 Suppressed. Still more specifically, the invention com boric acid and alkyl metaborate of between about 3 and prises a method for producing oxygenated derivatives par 15 carbons, said wt. percent based on said n-paraffin. ticularly rich in secondary alcohols comprising contacting a 6 to 20 carbon atom n-paraffin having an ultraviolet light absorbancy of between about 1 and 560 at 260-280 BACKGROUND OF INVENTION 25 mg. With oxygen in the presence of a boron compound Selected from the group consisting of boric oxide, boric Field of invention acid and an alkyl metaborate of from 3 to 15 carbons and A process directed to the partial oxidation of predomi a peroxide selected from the group consisting of di-t-butyl nantly non-aromatic hydrocarbon and hydrocarbon mix peroxide and t-butyl hydroperoxide. tures to produce a mixture of products, for example, 30 . In brief background absorbance (A) is related to the esters, acids, aldehydes, ketones and particularly secon concentration of the absorber, e.g., oxidation inhibiting dary alcohols. cyclic hydrocarbons in the 260-280 mu, range such as naphthalene, methyl naphthalene and butyl naphthalene Description of the prior art in the following way: In the past, one of the standard methods of manufac 35 A=e cl turing oxygenated products containing a significant alco where hol content is set forth in U.S. 1,947,989 which teaches A=absorbance contacting paraffinic hydrocarbons with oxygen in the e=extinction coefficient presence of oxidation catalyst of boric acid or boric oxide c=Concentration ingram moles to form hydrocarbon oxidates and borate esters and con 40 l-cellpathlength in centimeters (usually 1 cm.) verting the borate esters into alcohols through hydrolysis. U.S. 2,626,277 discloses the manufacture of higher fatty A is measured by means of a standard Spectrophoto acids and higher alcohols by contacting petroleum wax meter Such as a Cary Model 14M Recording Spectro with oxygen in the presence of organic peroxides having photometer. The sample to be tested for absorbance is boiling points greater than 300 F. The patent states cu 45 placed in a special silica cell and its absorbance is meas. mene hydroperoxide is an excellent example and lower ured against that of a pure reference solvent (e.g. isooc peroxides such as di-t-butyl peroxide are unsuitable. U.S. tane) which does not absorb in the same region as the 2,726,255 discloses a method of preparing fatty alcohols Sample solution. The e is a constant characteristic of the from aliphatic hydrocarbon of from 7 to 12 carbons by compounds being studied. The e values for various com contacting the hydrocarbon, e.g., dodecane with oxygen in 5) pounds are available in the literature. Further discussion the presence of a hydroperoxide such as t-butyl hydro of ultraviolet light absorbancy is found in E. A. Brande, peroxide or cumene hydroperoxide and an alkaline agent "Determination of Organic Structures by Physical Meth such as sodium hydroxide and further discloses the hy ods,” pp. 131-194, Academic Press, New York, 1955. drogenation of the product to upgrade in respect to the In detail, the method comprises contacting under production of alcohol. 55 liquid phase conditions, n-paraffin and mixtures thereof Although the prior methods were effective in producing from 6 to 20 carbons having an ultraviolet light absorb oxygenated products they are ineffective in producing ancy at 260-280 mps of between about 1 and 560 with OXygenates in the presence of the combination of boric oxygen at a temperature between about 150 and 200° C., anhydride, boric acid or an alkyl metaborate and cyclic preferably between about 165 and 185° C., in the pres hydrocarbons such as naphthalene, alkyl naphthalenes, 60 ence between about 1 and 15 wt. percent based on said and tetralin registering an ultraviolet light (UV) absorb n-paraffin of a boron compound selected from the group ancy in the 260-280 mu range. The combination of the consisting of boric oxide, boric acid and alkyl metaborate aforementioned cyclic hydrocarbons and boron com of from 3 to 15 carbons and between about 0.001 and pounds functions as a strong oxidation inhibitor, particu 5.0 Wt. percent based on said n-paraffin of a peroxide larly in the oxidation of n-paraffin. This fact previously 65 Selected from the group consisting of di-t-butyl peroxide resulted in the requirement of relatively expensive and and t-butyl hydroperoxide. The contacting is normally time consuming pretreating of the n-paraffin to remove the conducted for a period of between about 1 and 6 hours oxidation inhibiting cyclic hydrocarbon impurity there and preferably until between 5 and 50 wt. percent of from. Therefore, there was a need in the n-paraffin oxida O the n-paraffin reactant is converted into oxygenates. The tion art to develop a method which would permit oxida Oxygen is advantageously introduced into the reaction tion of n-paraffin using the boric anhydride, boric acid system at a rate of at least about 5 mls./min./100 g. 3,655,769 3 4. paraffin, preferably between about 10 and 150 mls./min./ The following examples further illustrate the invention 100 g. paraffin. but are not to be interpreted as limitations thereof. One of the critical features of the invention is the employment of t-butyl hydroperoxide or di-t-butyl hy EXAMPLE I droperoxide. When closely related peroxides and hydro This example illustrates the preparation of the buty peroxides are substituted for the peroxide material con metaborate selective oxidation director. templated herein in the method of the invention, little or A mixture of 62 (1 mole) of boric acid and 72 grams no oxidation takes place. Another important feature is (1 mole) of n-butanol was charged to a 500 mls, glass to utilize a peroxide amount of at least about 0.001 Wt. flask equipped with a magnetic stirrer, thermometer and percent based on the n-paraffin reactant. Lower quantities O a 6 inch helix pack column. The mixture was heated at produce a significantly reduced amount of desired oxida 110 to 122 C, until about 30 mls. of water were col tion products. Another essential feature of the invention lected from the distillate. All of the butanol layer of the is the use of boric oxide, boric acid or an alkyl metaborate distillate was recycled back to the reactor pot and the as defined. In the absence of the contemplated boron mixture was then heated at 121-138 C. until a total compounds the yield of the desired secondary alkanols is 5 sharply reduced. of 32 mls. of water was collected. The product was de The oxidation products are recovered from the reac termined to be n-butyl metaborate. tion mixture by standard means such as selective solvent extraction, fractional distillation and combinations there EXAMPLE II of. One such method of purification to recover secondary 20 This example illustrates the method of the invention alcohol calls for contacting the final reaction mixture with and the importance of employing t-butyl hydroperoxide water and separating the resultant organic phase there or di-t-butyl peroxide oxidation inhibitor suppressors in from, saponifying the organic phase with an aqueous the method of the invention. alcoholic solution of alkali metal, separating the saponi To a 300 ml. 3-necked flask, fitted with a thermometer, fied organic layer and subjecting the residue to fractional 25 fritted glass sparging device, stirrer and water separator, distillation to recover the desired secondary alkanol there was charged the n-paraffin reactant, boric acid or product. n-butyl metaborate and peroxide. The reactor was heated Examples of the normal paraffins contemplated herein to 175 C. and air was passed through the reaction mix are those of 6 to 20 carbons recovered from crude petro ture via introduction through the gas sparging device. The leum stocks. This recovery is usually accomplished by 30 course of the reaction was followed by periodically with first obtaining a cut via distillation or other means having drawing 5 or 10 mls. samples from the reaction by means the desired number of carbon atoms and then treating the of a pipet. The sample was added directly to 10 or 15 mls. desired fraction in a variety of ways to obtain a pre of water and stirred at 100° C. for 30 minutes. The solu dominant amount of n-paraffin. Such treatment methods tion was then cooled and the layers were separated. If n such as urea adduction or the employment of molecular 35 dodecane was the charge the aqueous layer was extracted sieves are illustrative. These standard methods produce with 5 or 10 ms. of benzene. The benzene extract and n-paraffin products with impurity amounts, e.g., between the organic layer were then combined, dried over anhy about 0.001 and 1.0 wt. percent of oxidation inhibiting drous calcium sulfate and analyzed by gas chromotogra aromatics and derivatives thereof giving the n-paraffin phy. If th mixed Co-C4 in-paraffins were charged, the product an ultraviolet light absorbancy of between about 40 benzene extraction step was omitted. 1 and 560 and 260-280 mu. Specific examples of the The test data and results are reported in subsequent n-paraffin reactants contemplated are dodecane having a Tables I and II. All runs were made at 175° C. using an naphthalene content of between about 99.0 and 99.999 air rate of 150 mls./min./100 grams of n-paraffin. Unless wt. percent and a Cio, C1, C12, C13 and C14 n-paraffins otherwise stated, the ultraviolet light absorbance at 260 and mixtures thereof containing between about 0.001 and 45 1.0 wt. percent naphthalene, methyl naphthalene, ethyl 280 mp of the n-dodecane charge stock was 4.7 and the naphthalene, butyl naphthalene, or tetralin and mixtures Co-C14 n-paraffin mixture was 12.2. thereof. Autogenous pressure is satisfactory although higher or lower pressures may be employed. 50 Although pure oxygen may be employed in the reac tion, it is preferred to employ air or synthetic mixtures of TABLE -REACTON CONDITIONS oxygen diluted with any inert gas such as nitrogen, helium Butyl meta Time, and argon. Run number Paraffin, g. borate, g. Peroxide, g. a hrs. Examples of the catalytic metaborate oxidation direc tors contemplated herein are butyl metaborate, isooctyl TBH, .05 ---- metaborate and dodecyl metaborate. The term "boric TBFI, 103.-- acid hereinbefore and hereinafter denotes all hydrated TB 0.10 DfEP0504. forms of boric oxide such as orthoboric acid, metaboric TBE, 0.45-...-- acid. Examples of the oxygenated products resulting from TB,027. the oxidation of n-paraffin such as n-dodecane are 2-dodec anol and all other isomeric secondary alcohols obtained from a dodecane. In addition, isomeric dodecanones, organic acids such as pentanoic acids and esters such as 65 i Control. dodecyl propionate can also be obtained as products of a TBHst-butyl hydroperoxide; DTBHs di-t-butyl sec-butyl hydroperoxide; NOHsin-octyl hydroperoxide;eroxide; TE = tetralinSBH = the oxidation of dodecane. Examples of the oxygenated hydroperoxide; CH=cumene hydroperoxide; BP =benzoyl peroxide. products resulting from the oxidation of a mixture of b Artificial chargestpck prepared by dissolving 0.6 g.of naphthalene ill liter of aromatic-free in-dodecane. Ultraviolet light absorbance at Co-C4 n-paraffins are 2-decanol, 2-undecanol, 2-dodec 260-280 nm was calculated to be 26.2. anol, 2-tridecanol, and all other isomeric secondary alco 70 Before introduction of oxygen, mixture was preheated for 3 hours at 140° C. and then oxidized for 2 hours at 175 C. hols obtainable from a mixture of Co-C4 in-paraffins. d The hydroperoxide was added in two equal portions. The first was The temperature of the reaction as heretofore stated added and the mixture was oxidized in the usual manner. The second was added and the mixture was heated at 100° C. for 2 hours followed by should be maintained at between about 150 and 200 C. 2 hours of oxidation at 175°C. and advantageously above the melting point of the n e Half hydroperoxide added initially and lalf after two hours of paraffinic reactant. 75 oxidation. 3,655,769 5 6 TABLE. I.--REACTION RESULTS C. in the presence of a boron compound selected from Tota the group consisting of boric oxide, boric acid and an Run number, alcohol plus Alkanol, Alkanone, alkyl metaborate of from 3 to 15 carbons and a peroxide Wit. percent, n-Paraffin, ketone, Wit. Wit. i.e. wt. percent wt. percent percent 2 percent 2 selected from the group consisting of t-butyl hydroperoxide 5 and di-t-butyl peroxide, said boron compound being pres A'------99.6 0.4 0.4 O B'------99.7 0.3 0.3 O ent in an amount of between 1 and 15 wt. percent based C------849 15.1 4.4 0.7 on said n-paraffin composition, and said peroxide being D 8.6 18.2 17.7 .1 present in an amount of between about 0.001 and 5 wt. E 82.7 6.34 6.3 1.04 percent based on said n-paraffin composition. F. 88.9 19, 16.7 ... 4 G 83.5 2. A method in accordance with claim 1 wherein said H 95.2 I- 86 contacting is continued for a period of time sufficient to 94 Kl 99.5 convert between about 5 and 50 wt. percent of said par L 99.9 affin into oxygenated derivative. M1 100 3. A method in accordance with claim 2 wherein said Ni 99.5 O'------99. n-paraffin is n-dodecane, said boron compound is butyl 1 Control. metaborate and said peroxide is t-butyl hydroperoxide. 2When then-paraffin was dodecane the alkaol was predominantly 4. A method in accordance with claim 2 wherein said Sec.-dodecanol and the alkanone was predominantly dodecanone. When then-paraffin was a Cio-C14 the alkano was predominantly a mixture of n-paraffin is a mixture of normal C10, C1, C2, C1 and Cio-Cia sec.-alkanols and the alkanone was predominantly a mixture of C14 alkanes, said boron compound is butyl metaborate Co-C14 alkanones. 20 and said peroxide is t-butyl hydroperoxide. As can be seen from the foregoing tables in control 5. A method in accordance with claim 2 wherein said runs A and B in which no peroxide was employed the n-paraffin is n-dodecane, said boron compound is butyl yield of corresponding oxygenated product (alkanol and metaborate and said peroxide is di-t-butyl peroxide. alkanone) was negligible. Control Runs K, L, M, N and O 6. A method in accordance with claim 1, wherein said demonstrate the use of peroxides and hydroperoxides 25 n-paraffin is n-dodecane, said member is naphthalene, said other than butyl hydroperoxide and di-tertiary peroxide boron compound is butyl metaborate and said peroxide in the method of the invention result in only negligible is t-butyl hydroperoxide. yields of oxygenated product. The remaining runs are rep 7. A method in accordance with claim 1 wherein said resentative of the method of the invention except for Run n-paraffin is a mixture of normal C10, C11, C1, C1s and J which is a comparative control in respect to Run I. 30 C14 alkanes, said boron compound is boric acid, and said I claim: peroxide is t-butyl hydroperoxide. 1. A method of oxidizing an n-paraffin composition of 6 to 20 carbons containing an impurity giving an ultra References Cited violet light absorbancy to said composition of between FOREIGN PATENTS about 1 and 560 at 260-280 mu, said impurity consisting 1,463,011 11/1966 France ------260-632 CB essentially of a member selected from the group consist ing of naphthalene, alkyl naphthalene where said alkyl HOWARD T. MARS, Primary Examiner group has from 1 to 4 carbons, tetralin and mixtures there of, consisting of contacting said n-paraffin composition U.S. C. X.R. with oxygen at a temperature between about 150 and 200 40 260-533 R, 608, 632 CB