ISOMERIZATION OF ALLYLIC HALIDES WITH QUATERNARY SALTS

Abstract: A method for the isomerization of allylic halides is dis­ closed, improved by the presence of an organic quaternary salt. The improved method of the invention requires less energy for completion of the isomerization and shortens the isomerization times.

Description: ISOMERIZATION OF ALLYLIC HALIDES WZTH QUATERNARY SALTS BACKGROUND OF THE INVENTION Field of the Invention The invention relates to the isomerization of allylic halides. Brief Description of the Prior Art Representative of the prior art is the description given in the U. S. Patent 3,819,730. In spite of the availability of several known methods of isomerizing allylic halides, there has remained a need for economical processes, saving of energy. The method of the present invention is such an improvement over the prior art, requiring low temperatures and short isomerization times. SUMMARY OF THE INVENTION The invention comprises in a method for isomerizing an allylic halide to its allylic isomer which comprises I isomerizing the allylic halide in the presence of a catalytic proportion of a hydrogen halide and a copper catalyst, the improvement which comprises; carrying out the isomerization in the presence of an organic quaternary salt selected from those of the formula: EMI2.1 wherein X is selected from the group consisting of an organic and inorganic anion such as nitrate, benzoate, phenylacetate, hydroxybenzoate, phenoxide, hydroxide, cyanide, nitrite; particularly preferred are chloride, bromide, iodide, methyl sulfate, ethyl sulfate and the like; M represents nitrogen, arsenic, or phosphorus. Rl, R2, R3j and R4 are each independently selected from one of those groups consisting of hydrocarbyl and substituted hydrocarbyl provided that when one or both of R1 and R2 contain from 1 to 4 carbon atoms, inclusive, the remainder of R moieties will each contain from 6 to 25 carbon atoms, or El and R2 may be taken together to represent a diva lent moiety attached to the atom M, and which is selected from the group consisting of alkenylene and hydrocarbyl-substituted alkenylene having 5 to 10 carbon atoms, inclusive, in the ring thereof; or R1 and R2 may be taken together with the atom of M to which they are attached to represent a divalent or monovalent moiety selected from the groups consisting of those having the formula: EMI3.1 wherein A represents nitrogen, oxygen, sulfur, phosphorus. and the like; and R6 and R7 are each selected from ii alkenylene and hydrocarbyl-substituted alkenylene of 1 to 25 carbon atoms, inclusive, m, n and q are each integers of 0 to 1 and the sum of m + n is 1 or 2. The term "halide" as used herein is embracive of Ii chloride, bromide and iodide. The term "hydrocarbyl" as used herein means the monovalent moiety obtained upon removal of a hydrogen atom from a parent hydrocarbon. Representative of hydrocarbyl are are alkyl of 1 to 25 carbon atoms, inclusive, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, undecyl, decyl, dodecyl, octadecyl, nonodecyl, eicosyl, heneicosyl, docosyl, tricosyl, tetracosyl, pentacosyl and the isomeric forms thereof; aryl of 6 to 25 carbon atoms, inclusive, such as phenyl, tolyl, xylyl, naphtyl, biphenyl, tetraphenyl and the like; aralkylof 7 to 25 carbon atoms, inclusive, such as benzyl, phenethyl, phenpropyl, phenbutyl, phenhexyl, napthoctyl and the like; cycloalkyl of 3 to 8 carbon atoms, inclusive, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctylandthe like; alkenyl of 2 to 25 carbon atoms, inclusive, such as vinyl, allyl, butenyl, pentenyl, hexenyl, octenyl, nonenyl, decenyl, undececyl, dodecenyl, tridecenyl, pentadecenyl, octadecenyl, pentacosynyl and isomeric forms thereof. The term "alkenylene" means the divalent moiety obtained on removal of two hydrogen atoms, each from a non-adjacent carbon atom of a parent hydrocarbon and includes alkenylene of 3 to 10 carbon atoms, inclusive, such as 1,3-propenylene, 1,4-butenylene, 1,5-pentenylene, 1,8-octenylene, l,10-decenylene and the like. The terms "substituted hydrocarbyl" and "substituted alkenylene" as used herein mean the hydrocarbyl or alkenylene moiety as previously defined wherein one or more hydrogen atoms have been replaced with an inert group, i.e. a chemical group which does not adversely affect the desired function of the organic quaternary salt of formula (I). Representative of such groups are aminophosphino-, hydrocarbyl, quaternary nitrogen (ammonium), quaternary phosphorus (phosphonium), hydroxyl-, alkoxy, mercapto-, alkyl, halo-, phosphate, phosphite, carboxylate groups and the like. It is preferred to use compounds wherein the halogen is chloride. The process of the invention is especially carried out at a temperature of OOC to 500C. A further preferred embodiment of the invention is the use of cuprous chloride as copper catalyst. It is furthermore preferred to use a copper catalyst within the weight range of 0.01 to 2.0% of allylic halide whereby the molar ratio of organic quaternary salt to copper catalyst should be 0.01 to 5.0. It is preferred to carry out the isomerization for a period of 0.1 to 10.0 hours. Especially preferred is the use of a mixture of tri (alkyl)methyl ammonium chlorides where the alkyl portion comprises a chain of from eight to ten carbons as the organic quaternary salt. Especially preferred are furthermore compounds selected from the group consisting of methyltrioctylammonium chloride, dimethylbenzylstearyl ammonium, N,N-cetylethylmorpholinium ethosulfate, benzyl hydroxyethyl(2) cocoimidazolium chloride, N-tallow penta methyl propane diaininoniumchloride, benzyltrioctyl ammonium bromide and propyltriphenyl phdsphonium bromide. As lateron discussed the process of the invention may be carried out especially for isomerizing linalyl chloride or 3-chloro-3-methyl-1 -butene. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The method of the invention may be employed to isomerize any allylic halide to obtain its allylic isomer. In other words, a tertiary allylic halide may be isomerized to the corresponding secondary or primary allylic halide and the secondary allylic halide may be isomerized to the corresponding primary allylic halide. Representative of an advantageous isomerization according to the method of the invention is the isomerization of linalyl chloride to the geranyl and neryl chlorides according to the schematic formulae: EMI6.1 linalyl geranyl neryl chloride chloride chloride II The method of the invention is not limited to the isomerization of linalyl chloride to geranyl and neryl chlorides but may be used to isomerize any allylic halide to its less allylic isomer. Other representative allylic halides which may be advantageously isomerized include 3,4dichlor1-hutene and especially 3-chloro-3-methyl-1-butene and like allylic halides. The method of the invention is an improvement over # isomerizations carried out in the presence of hydrogen halides and copper catalysts. Representative of hydrogen halides so employed are hydrogen chloride and hydrogen bromide. In general, catalytic proportions of the hydrogen halide are used. Catalytic proportions are generally within 1 the range of from about 0.01 to 5 percent by weight of the starting halides, preferably 0.1 to 1.0 percent. The copper catalysts employed may be any copper I compound having a valency of 2 or less, including metallic copper. Any copper compound convertible to the halide such as the bromide, iodide or chloride under conditions of the reaction may also be used. Representative of copper catalysts advantageously employed are the chloride, bromide, carbonate, oxide, acetate, formate, sulfate and like ; derivative cupric and cuprous compounds. Preferred as the copper catalyst in the improved process of the invention is cuprous chloride. Catalytic proportions of the copper catalyst are generally within the weight range of from about 0.01 to 2 percent of the allylic halide starting compound, preferably about 0.5 percent. Organic quaternary compounds of the formula (I) given above are generally well known as are methods of their preparation. Representative of such organic quaternary compounds are trioctylmethylammonium chloride, tetraoctadecylammonium chloride, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzyiammonium chloride, hexadecyldimethylbenzylammonium chloride, N,N-cetylethylmorpholinium ethosulfate, methyl (1) cocoamido- ethyl (2) cocoimidazolinium methyl sulfate, -N-tallow- pentamethylpropanediammonium dichloride, trioctylmethylphosphonium bromide, N,N-soya ethylmorpholinium ethosulfate, hexadecylpyridinium chloride, benzyl hydroxyethyl(2)cocoimidazolinium chloride, dodecyldimethyl (ethylbenzyl)- ammonium chloride, tetradecyldimethyl (ethylbenzyl) ammonium chloride, hexadecyldimethyl(ethylbenzyl)ammonium chloride, octadecyl-dimethyl(ethylbenzyl)ammonium chloride, octadecyldimethylbenzylammonium chloride, methyl bis (2-hydroxyethyl)cocoammonium chloride, methyl(l)soyaamido ethyl(2)soyaimidazolinium methyl sulfate and the like. Commercially available quaternary salts or purified forms of quaternary salts may be used in the preferred process of the invention. It will be appreciated that under specific conditions of operating the process of the invention, certain of the above described compounds of the formula (I) given above have advantages over other compounds of the same general formula. Selection of a particular compound (I) for use under specific process conditions for optimum yields may be made by trial and error techniques. We have observed however that there are advantages associated with a mixture of trialkylmethylammonium chlorides where the alkyl portion consists of a chain of from eight to ten carbon atoms. For example, Adogen 464 (Sherex Chemical Co.) The organic quaternary salt is used in a proportion to I isomerize at least some of the'allylic halide according to the method of the invetion. Such a proportion is generally within the range of from about 0.01 to 10 percent by weight of the halide charge, preferably 0.2 to 2.5 percent. Optimum proportions will depend to some extent upon the salt selected and may be determined by trial and error technique. Generally the preferred molar ratio of compound (I) to l! copper catalyst is from 0.01 to 5.0. The method of the invention may be carried out by , admixing the starting allylic halide with the hydrogen halide, copper catalyst and salt compound of the formula (I) in a suitable reaction vessel for a sufficient period of Ii time to effect the desired isomerization. The controlling reaction rate in the method of the invention is the isomerization of the allylic halide to the desired allylic isomer. This is controlled by residence time in the reaction zone. We have found that in isomerization of linalyl chloride the preferred minimum total residence time is within the range of from 0.1 to 10 hours and most preferably 0.5 to 5 hours under preferred operating temperatures. Although the method of the invention may be carried out under a wide range of operating temperatures, i.e. within the range of from about OOC. to 50 C., it is preferred to do so at a temperature of from 0 C to 30 C. and most preferably 0 C. to 20 C. The method of the invention is not dependent upon pressure, and may be carried out at atmospheric, sub-atmospheric or super-atmospheric pressures. Progress of the isomerization may be monitored by conventional analytical technuques. When it has been determined that isomerization occured to a maximum desired point, the product mixture may be passed from the reaction apparatus. The desired allylic halide isomer may then be separated from the reaction mixture employing conventional and known techniques including washing, decantation, distillation and like techniques. The following examples describe the manner and process of making and using the invention and set forth the best mode contemplated by the inventors of carrying out the invention but are not to be construed as limiting. All parts given are by weight unless otherwise indicated. EXAMPLE 1 To 8.0 g of myrcene hydrochlorides, consisting of 37.0 parts linalyl chloride, 9.5 parts neryl chloride, 7.0 parts geranyl chloride, 5.0 parts alpha-terpinyl chloride and 41.5 parts hydrocarbons, was added 0.03g cuprous chloride, 0.11g Adogen 464* and 0.02g of hydrogen chloride gas. The mixture Ii was stirred at 100C. for 7 hours. Samples were withdrawn at 1-2 hour intervals, neutralized with aqueous sodium hydroxide, and analyzed by gas chromatography. Product content of linalyl, neryl and geranyl chloride (abbreviated LCl, NCl and GCl respectively) are shown below. The amount of the required to reduce the LCL content by one-half was 1 hour. * A mixture of trialkylmethylammonium chlorides where the alkyl groups comprise 44% of C10, 52% of C8, 2% of C6 and 2% of C12. Time (Hrs) Composition of Product (8) I ¯ LCl NCl GCl 0 37.0 9.5 7,0 1.5 10.5 16.4 23.5 3.0 7.2 17.2 25.5 6.5 5.1 17.5 26.8 EXAMPLES 2-11 Myrcene hydrochlorides were subjected to isomerization # under the same conditions and amounts as described in # i Example 1 using 0.03g cuprous chloride, 0.02g hydrogen chloride gas, and an organic quaternary salt as described in Table 1 to obtain the results shown in Table 1 below. The Examples 10 and 11 are not of the invention but are made for comparative purposes. TABLE 1 Example Quaternary Salt Amount of time to GCl:NCl No. And Amount Used Reduce LCl Content Ratio After By One-half (hrs.) 6.5 hours 2 None 5-6 1.4 3 Methyltrioctyl ammonium chlor # ide, 0.11 g 1 1.4 ! 4 Dimethylbenzyl- stearyl ammonium chloride. 0.11g 1 1.6 5 N,N-cetylethyl morpholinium Ii ethosulfate, 0.12g 1 1.7 6 Benzyl hydroxyethyl (2) cocoimidazolium chloride, 0.12g 1 1.8 7 7 N-Tallowpenta- methyl propane diamonium dichloride, 1.12g 1 1.9 i 8 Benzyltrioctyl ammonium bromide, 0.14g 2 1.4 9 Propyltriphenyl phosphonium bromide, 0.15g 3 1.4 10. Trimethylbenzyl ammonium chloride, u 0.05 gm > 10 0.9 # 11 Trimethylbutyl ammonium bromide, 0.05 gm > 10 0.8 EXAMPLES 12 To 6.0 g of isoprene hydrochlorides consisting of 63 parts 3-chloro-3-methy-l-butene (abbreviated 3,3,1-CMB) and 37 parts l-chloro-3-methyl-2-butene (abbreviated 1,3,2-CMB) was added 0.03g cuprous chloride, 0.02g hydrogen chloride gas and 0.15 gms of benzylhydroxyethyl (2) coco i imidazolinium chloride. The mixture was stirred at IOOC. for 2 hours. A sample was withdrawn after 2 hours, neutralized with aqueous sodium hydroxide, and analyzed by nuclear magnetic resonance spectroscopy. The results obtained are shown in Table 2, below. TABLE 2 Product Composition (%) ! Hours 3,3,1-CMB 1,3,2-CMB 0 63 37 2 11 89 EXAMPLE 13 To 4.-0g of-dichlorobutene mixture consisting of 97 parts 3,4-dichloro-l-butene and 3 parts 1,4-dichloro-2butene was added 0.02g cuprous chloride, an organic quaternary salt as described in Table 3, below, and 0.01g hydrogen chloride gas. The mixture was stirred at 500C. for 5 hours, neutralized with aqueous sodium hydroxide and analyzed by gas chromatography. 3,4-dichloro-l-butene and l,4-dichloro-2-butene are abbreviated 3,4-DCB and 1,4-DCB, respectively. TABLE 3 Quaternary Salt And Composition of Product (%) Amount Added 3,4-DCB Cis-1,4-DCB trans-1,4-DCB None 91 1 8 Adogen 464*, 0.009g 48 1 51 Trimethylbenzyl- ** ammonium chloride, 0.04g - 67 1 32 * Sherex Chemical Co.; A mixture of tri(alkyl)methyl ammonium chlorides where the alkyl portion is a chain of from 8 to 10 carbon atoms. ** Not a-compound- of the formula (I) for control purposes.

Claims: WHAT IS CLAIMED: 1. In a method for isomerizing an allylic halide to II its allylic isomer which comprises isomerizing the allylic halide in the presence of a catalytic proportion of a hydrogen halide and a copper catalyst, the improvement which comprises; carrying out the isomerization in the presence of # an organic quaternary salt selected from those of the formula: EMI16.1 wherein X is selected from the group consisting of organic and inorganic amnions such as nitrate, benzoate, phynylacetate, hydroxybenzoate, phenoxide, hydroxide, cyanide, nitrite; particularly preferred are chloride, bromide, iodide, methyl sulfate, ethyl sulfate and the like; M represents nitrogen, arsenic, or phosphorus. R1, R2, R3, and R4 are each independently selected from one of those groups consisting of hydrocarbyl'and substituted hydrocarbyl provided that when one or both of R1 and R2 contain from 1 :1 to 4 carbon atoms, inclusive, the remainder of R moieties will each contain from 6 to 25 carbon atoms, or R1 and R2 may be taken to represent a divalent moiety attached to the atom M, and which is selected from the group consisting of alkenylene and hydrocarbyl-substituded alkenylene having 5 to 10 carbon atoms, inclusive, in the ring thereof; or R1 and R2 may be taken together with the atom of M to which they are attached to represent a divalent or monovalent moiety selected from the groups consisting of those having the forumla: EMI17.1 wherein A represents nitrogen, oxygen, sulfur, phosphorus and the like; and R6 and R7 are each selected from. alkenylene and hydrocarbyl-substituted alkenylene of 1 to 25 carbon atoms, inclusive; m, n and q are each integers of 0 to 1 and the sum of m = n is 1 or 2. 2. The process of claim 1 wherein the halogen is chlorine. 3. The process of claim lor 2 carried out at--a temperature of 00C to 500C. 4. The process of one of the claims I - 3 wherein the copper catalyst is cuprous chloride. 5. The process of one of the claims 1 - 4 wherein the catalytic proportion of copper catalyst is within the weight range of i 0.01 to 2.0% of allylic halide. 6; Theprocess of one of the claims 1-5; wherein the molar ratioof organic quaternary salt to copper catalyst is 0.01 to 5.0. 7. The process of one of the claims 1 - 6 wherein the isomerization is carried out for a period of 0.1 to 10.0 hours. 8. The process of one of the claims 1 - 7 wherein the organic I quaternary salt is a mixture of tri(alkyl)methyl ammonium chlorides where the alkyl portion comprises a chain of from eight to ten carbons 9. The process of one of the claims 1 - 8 wherein the organic quaternary salt is selected from a group consisting of methyltrioctylammonium chloride, dimethylbenzylstearyl ammonium, N,N-cetylethylmorpholinium ethosulfate, benzyl hydroxyethyl(2) cocoimidazolium chloride, N-tallow penta methyl propane diammoniumdichloride, benzyltrioctyl ammonium bromide and propyltriphenyl phosphonium bromide. 10. The process of one of the claims 1 - 9 wherein the allylic halide is linalyl chloride. 11. The process of one of the claims 1 - 9 wherein the allylic hallide is 3-chloro-methyl-1-butene.

Inventors: MCELLIGOTT, LOIS T., MITCHELL, PETER W.D., SASSER, DAVID E.
Applicants: UNION CAMP CORPORATION
Application year: 1984
Main classification: C07C17
IPC codes: C07C21, B01J31, C07C17, C07B61, C07C67