United States Patent (19) ’11) 4,095,037 Stapp 45) June 13, 1978 54 METHOD FOR THE oxIDATION OF A 56) References Cited CONJUGATED DOLEFN U.S. PATENT DOCUMENTS 3,238,225 3/1966 Brill................................ 260/346.1 (75) Inventor: Paul R. Stapp, Bartlesville, Okla. 3,432,558 3/1969 Ryland ................................. 260/604 3,670,014 6/1972 Fernholz .......................... 260/497 A 73 Assignee: Phillips Petroleum Company, 3,755,423 8/1973 Onoda .............................. 260/497 A. Bartlesville, Okla. 3,922,300 11/1975 Onoda .............................. 260/497. A Primary Examiner-James O. Thomas, Jr. 21 Appl. No.: 721,645 Assistant Examiner-Michael Shippen 22 Filed: Sep. 8, 1976 57 ABSTRACT A conjugated diolefin is reacted with a carboxylic acid, (51) Int, C.’......................... CO7C 67/05; B01J 23/16 a carboxylic acid anhydride, or a mixture thereof, in the (52) U.S.C. .................................... 560/246; 260/410; presence of oxygen and a catalyst comprising a com 260/410.6; 260/465.4; 560/1; 560/106; pound of bismuth, an alkali metal compound and a 560/112; 560/122; 560/228; 560/230; 252/438 source of nitrate ion. 58 Field of Search ........... 260/497 R, 497 A, 476 R, 260/410, 40.6, 465.4, 468 R, 487 11 Claims, No Drawings 4,095,037 1. METHOD FOR THE OXDATION OF A . R. R. R. 1) CONJUGATED DOLEFN C-CEC as R. BACKGROUND OF THE INVENTION The invention relates to a method suitable for the In said formula (1), R- is selected from the group oxidation of a conjugated diolefin. In another aspect, consisting of H-, F-, CL-, Br-, -, -CsN, the invention relates to a composition useful as a cata lyst. O It is desirable to oxidize conjugated diolefins, such as 10 -C-OneR', 1,3-butadiene and/or 2-methyl-1,3-butadiene to pro duce various compounds such as the ethylenically un and the monovalent hydrocarbyl radicals of up to 12 saturated esters. An example is the oxidation of 1,3- carbon atoms such as alkyl, aryl, cycloalkyl and combi butadiene to produce 1,4-diacetoxy-2-butene. The nations such as alkaryl, aralkyl, cycloalkylaryl and the diacetoxybutene is then easily converted, by processes 5 like. For the group. well known in the art, to other compounds such as tetrahydrofuran or 1,4-butanediol. Although there are O various processes and catalysts known which are useful for the oxidation of a conjugated diolefin, most of these 20 processes are relatively expensive to carry out and fre -R is selected from the group consisting of-H, alkyl, quently corrosion of process equipment is a problem. and the aryl radicals of up to 10 carbon atoms. It is Therefore, new processes and catalysts are desirable in understood that the total number of carbon atoms in all an effort to more fully develop the art and improve the substituents (R-) combined will not exceed 12. overall process. 25 Some suitable cyclic conjugated diolefins are repre An object of the present invention is to oxidize a sented by the following general formula: conjugated diolefin. Another object of the invention is to oxidize a conju 2) gated diolefin more economically than can be done presently. 30 Another object of the invention is to oxidize a conju gated diolefin with minimum corrosion of process equipment. Another object of the invention is to provide a cata lyst useful for the oxidation of conjugated diolefins. 35 Other objects, advantages and aspects of the present Said cyclic conjugated diolefins contain from 5 to 16 invention will be apparent to those skilled in the art carbon atoms per molecule. In said formula (2), R- has after studying the specification and appended claims. the same meaning as the formula (1), and n is an integer 40 having a value of from 1 to 12. It is further understood SUMMARY OF THE INVENTION that the total number of carbon atoms in all substituents In accordance with the invention, a conjugated diole (R-) combined will not exceed 11. fin is reacted with a carboxylic acid, a carboxylic acid Presently preferred conjugated diolefins are those anhydride, or a mixture thereof, in the presence of oxy containing only carbon and hydrogen because use of gen and a catalyst comprising a compound of bismuth, 45 such materials produces products finding particular an alkalimetal compound, and a source of nitrate ion. In applicability today. For the same reason, the com order to simplify the purification and separation steps, it pounds especially preferred for use in the instant inven is preferred to use both a carboxylic acid and a carbox tion are 1,3-butadiene and 2-methyl-1,3-butadiene (iso ylic acid anhydride, which corresponds to the carbox prene) to produce the corresponding 1,4 diacetoxy de 50 rivatives. Examples of suitable conjugated diolefins ylic acid. include 1,3-butadiene, 2-methyl-1,3-butadiene, 2 Further in accordance with the invention, a composi chloro-1,3-butadiene, 2-ethyl-1,3-butadiene, 2-chloro-3- tion comprises a compound of bismuth, an alkali metal methyl-1,3-butadiene, 1,4-diphenyl-1,3-butadiene, 1,3- compound, and a source of nitrate ion. hexadiene, 1,3-pentadiene, 1,3-octadiene, 1,3-cyclohex DETAILED DESCRIPTION OF THE 55 adiene, 1,3-cyclooctadiene, 1,3-cyclododecadiene, 2 INVENTION cyano-1,3-butadiene, 2-carbethoxy-1,3-butadiene, cy clopentadiene, 5-methyl-1,3-cyclohexadiene, 2,4- The conjugated diolefins suitable for use in the pro cyclohexadiene-1,2-dicarboxylic acid, octafluoro-1,3- cess of the invention are selected from a wide range of cyclohexadiene, hexachlorocyclopentadiene, 5,6,7,8- compounds. Generally, the conjugated diolefins em 60 tetrabromo-1,3-cyclooctadiene, 2-cyclohexyl-1,3- ployed in the process of the instant invention are those butadiene, 2-methylene-3-butenoic acid and 2,4-pen having from 4 to 16 carbon atoms per molecule. Suit tadienenitrile. able conjugated diolefins include acyclic, as well as Mixtures of conjugated olefins are also suitable; how cyclic compounds, and further include compounds ever, a mixture of products will result which may be which have substituents such as halogen, cyano, or difficult to separate into the individual component prod carbalkoxy radical present in the molecule. CtS. Some suitable acyclic conjugated diolefins are repre The conjugated diolefin is reacted with at least one sented by the following general formula: . compound selected from the group consisting of a car 4,095,037 3 boxylic acid and a carboxylic acid anhydride to produce the corresponding diacyloxyalkene. In most instances, it O is preferred to use a carboxylic acid and the correspond ing acid anhydride because the use of the corresponding -C-O-R" acid anhydride, in addition to the carboxylic acid, 5 substituted derivatives thereof wherein up to 4 of said serves to simplify the purification and separation steps halogen, cyano or by reducing the amount of by-products which contain free hydroxy groups. However, it is within the scope of the invention to use a carboxylic acid alone, a carbox ylic acid anhydride alone, a carboxylic acid and a car 10 boxylic acid anhydride of a different carboxylic acid or substituents can be present in said radical. The dicarbox a carboxylic acid and the corresponding acid anhy ylic acids also contain from 2 to 18 carbon atoms per dride. If the reaction is carried out using a carboxylic molecule. The group R' has the same meaning as that acid and a carboxylic acid anhydride of a different car 15 given in the discussion of general formula (1) above. boxylic acid, a mixture of reaction products normally Acetic acid and acetic anhydride are presently the results, preferred carboxylic acid and acid anhydride for use The carboxylic acids and acid and acid anhydrides according to the process of this invention. Examples of suitable for use in the invention are selected from a large other suitable carboxylic acids and acid anhydrides variety of compounds. Generally, the acids and acid include acetic acid, propanoic acid, butanoic acid, pen anhydrides include mono- and dicarboxylic acids and tanoic acid, hexanoic acid, octanoic acid, dodecanoic acid anhydrides having from about 2 to about 18 carbon acid, octadecanoic acid, cyclopentanecarboxylic acid, atoms per molecule. Such compounds include both cyclohexanecarboxylic acid, benzoic acid, chloroacetic aromatic and aliphatic compounds. Furthermore, they acid, cyanoacetic acid, trichloroacetic acid, 2 can contain halogen or cyano groups or other substitu 25 bromododecanoic acid, 2-ethylhexanoic acid, oxalic ents which are essentially inert to the oxidizing condi acid, succinic acid, adipic acid, terephthalic acid, 2 tions employed for the process of this invention. It is bromobutanoic acid, ethyl hydrogen adipate, 4 preferred, of course, that the carboxylic acid employed chlorobenzoic acid, 4-cyanobenzoic acid, 2,3,4,5-tetra be normally liquid or at least liquid under the conditions 30 chlorobenzoic acid and ethyl hydrogen-o-phthalate, employed for the reaction for ease in handling. and the respective acid anhydrides. Mixtures of carbox Some suitable monocarboxylic acids for use in the ylic acids and acid anhydrides can be used; however, a instant invention are represented by the general for mixture of reaction products normally results. mula: The oxidation catalyst employed in accordance with 35 the invention comprises a compound of bismuth, a com R"-COH (3) pound of an alkali metal and a source of nitrate ion. The bismuth compound can be in the form of nitrates, ox wherein R" is selected from the group of radicals con ides, halides and mixtures thereof. Examples of suitable sisting of alkyl, aryl, cycloalkyl or combinations such as bismuth compounds include bismuth nitrate, bismuth alkaryl, aralkyl, cycloalkylaryl and the like, or halogen oxychloride, bismuth oxyfluoride, bismuth oxynitrate, , cyano- or bismuth tribromide, bismuth trichloride, bismuth triflu oride, bismuth triiodide, and bismuth trioxide.