DE2049937A1 - Rhodium or ruthenium complexes and metal halides - as isomerisation catalysts for conjugated diene prodn - Google Patents

Abstract

Complex cpds. of mono- and trivalent Rh and/or di- and trivalent Ru in combination with metal halides such as the chlorides and/or bromides of Cu(II), Hg(II), Al, Sn(II) and (IV), Sb(III) or Bi(III), are used as catalysts for isomerisation of olefinically unsaturated cpds. with formation of structures with conjugated double bonds. Products are useful intermediates for organic syntheses e.g. oligomerisation and polymerisation pref. products from isomerisation of polyunsaturated 6-24C acids or esters are useful raw materials for paint industry. Rh- and/or Ru complexes pref. contain halogen, esp. Cl, ligands; pref. co-catalyst is a chloride, esp. SnCl2.2H2O; and pref. catalyst compsns. contain Rh- and/or Ru complex and co-catalyst in mol. ratio 1:1 to 1:15, esp. 1:2 to 1:10. Isomerisation is effected at 50-200 degrees C.

Description

"Isomerization Process" The invention relates to a process for Isomerization of olefinically unsaturated compounds with the formation of structures with conjugated double bonds.

It is known to use complexes containing rhodium and ruthenium as catalysts for certain syntheses, e.g. oxo and hydrogenation processes. Specific Complexes of rhodium have also been used as isomerization catalysts. For example, from the literature Tetrahedron Letters 1968, p. 3797, is known, that substituted 1,4-cyclohexadienes in the presence of [(C6H5) 3P] 3 RhCl to corresponding 1,3-Cyclohexadienes can be isomerized. But this process is obvious very favored, because an isomerization of phenylbutenes to compounds which the double bond in the side chain in conjugation to the aromatic system could only be achieved to a small extent when using this catalyst as from the work of Blum and Pickholt, Israel J. of Chem. 7, (1969), P. 723> follows.

You may have made your own experiments with this and similarly structured Complexes of divalent ruthenium in the case of longer-chain, polyunsaturated ones Olefins or substituted olefins have no isomerization to compounds with Conjudic structures can be achieved.

It has now been found, surprisingly, that by adding certain cocatalysts the catalytic activity of such complexes as well as other rhodium and ruthenium compounds with regard to the formation of structures with conjugated double bonds can be greatly increased.

Suitable cocatalysts are those which are used to form a metal-metal bond to the central atom of the rhodium- or ruthenium-containing catalyst complex or to Formation of halogen bridge complexes are capable and on these tracks one cause a strong trans effect at the central atom, which increases the activity of the catalyst complex causes. Metal compounds capable of doing this are the chlorides and / or bromides of in particular copper (II), mercury (II), antimony (III), bismuth (III), aluminum, Tin (II) and Tin (IV).

The invention accordingly provides a method for catalytic Isomerization of olefinically unsaturated compounds with the formation of structures with conjugated double bonds, which is characterized in that as isomerization catalysts Complex compounds of mono- and trivalent rhodium and / or bivalent and trivalent Ruthenium in combination with metal halides from the class of chlorides and / or Bromides of copper (II), mercury (II), aluminum, tin (II) and (IV), antimony (III), and Bismuth (III) can be used.

As a rule, compounds are used as complexes of rhodium and ruthenium into consideration, which in addition to halogen ligands contain nonionic ligands of the following types: Alkyl and aryl compounds of elements of main group 5 of the periodic table and sulfur, for example triphenylamine, triphenylphosphine, triphenylarsine, Triphenylstibine, tributylphosphine, tricyclohexylphosphine, tritolylphosphine, pyridine, Toluidine, diethyl sulfide, dibutyl sulfide; Carbon monoxide, possibly in combination with ligands of the above Gnanten kind; mono- or polyunsaturated compounds aliphatic, cycloaliphatic and / or aromatic character, in particular ethylene, butadiene, Acrylonitrile, 1,5-hexadiene, cyclooctene, cyclooctatetraene, 1,3-cyclohexadiene, cycloheptatriene, Cyclooctadiene-1,5, norbornadiene, benzene.

The formulaic composition of the metal complexes depends on the type of ligands and the valence of the central atom.

Complexes with ligands from the group of alkyl and aryl compounds the elements of the 5th main group and sulfur can be given by the following general Formula are shown: (Ligand) 3 MeHalx where x is the e valence of the central atom means and up to two of the above-mentioned ligands can be replaced by CO.

In the case of the ligands from the group of unsaturated compounds and pure carbonyl complexes, the following structures are possible: I [(Ligand) 2 MeHalx] 2 II [(Ligand # MeHalx] 2 III (Ligand) 2 MeHalx (x = valence of the central atom), where type I essentially in the case of monoolefinic and CO ligands, types II and III are formed in the case of di- and polyolefinic and aromatic ligands.

Preference is given to complexes in which chlorine is present as the halogen ligand.

Examples of complexes of the type described are: [(C6H5) 3P] 3 RhCl, [(C6H5) 3P] 3 RhCl3, [(C6H5) 3P3 2 (CH3C6H4NH2) 3 RuCl2, [(C4H9) 2S3] RhCl3, [(C2H5) 2S3] RuCl3 [Rh (CO) 2Cl] 2 [(ethylene) 2 RhCl] 2, [(cyclooctene) 2RhCl] 2 [hexadiene-1,5 RhCl] 2, (cycloheptatriene) 2 # RuCl2 (benzene) 2 RuCl2.

The rhodium and ruthenium complexes mentioned are known from the literature Process generally by reacting the metal halides in question with the compounds suitable as ligands described can be prepared in alcoholic solution.

For their use in the method according to the invention, the Complexes in some cases also in situ by adding the respective components be formed to the reaction mixture.

The chlorides to be used according to the invention as cocatalysts and Bromides of copper (II), mercury (II), aluminum, tin (II) and (IV), antimony (III) and bismuth (III) can be in commercial form, i.e. possibly containing water of crystallization come into use. Mixtures of the aforementioned cocatalysts and Mixed halides, such as Sn Br2 C12 and the like. can be used.

The chlorides of the metals mentioned are preferred as cocatalysts used. Particularly beneficial results are obtained with tin chlorides and in particular obtained with the compound Sn Cl2 2 H20. The catalyst combination to be used according to the invention can contain metal complex and cocatalyst in a molar ratio of 1: 1 to 1:15.

In some cases, e.g. in the case of rhodium (I) triphenylphosphine and diolefin complexes and tin (II) chloride as cocatalysts also know the crystalline ones stable complex / cocatalyst combinations are used. These have the defined formula-based composition: [(c6H5) 3PJ3 Rh Sn C13 or (diolefin) 2 Rh Sn Cl3.

In general, however, it is advisable to use a molar excess of the To use cocatalyst. The optimal molar ratio of metal complex to Cocatalyst is in the range from 1: 2 to 1:10.

The isomerization reaction in the presence of the catalyst combinations described is carried out at temperatures between 50 and 2000 C. The applicable one in each case The temperature depends on the complex used, i.e. on its thermal Stability and, on the other hand, the olefinic starting material to be converted.

With the isomerization process according to the invention, both isomerizations within a C-chain as well as isomerizations to conjuene structures with inclusion corresponding substituents can be achieved. As starting materials can accordingly di- and polyolefinic compounds with isolated double bonds, such as pentadiene-1.4, Hexadiene-I.4, decatriene-1.4.9, linoleic acid and derivatives, linolenic acid and derivatives, as well as monoolefinic compounds in which a conjugation of the double bonds can occur to a substituent, can be used. Examples of the latter Type of starting materials are phenylbutenes, vinylacetic acid, allylacetic acid, 3-cyclohexenecarboxylic acid, Itaconic acid, allylacetone, butene-3-nitrile.

Preferred starting materials are polyunsaturated higher carboxylic acids in the form of their esters with lower monohydric alcohols or the triglycerides and especially in the form of the free carboxylic acids. Examples of such starting materials, which isomerizes, as a rule, with the formation of conjune structures in the C chain are: heptadiene-2.5-acid, undecatriene-2.5.9.-acid, linoleic acid, linolenic acid, Arachidonic acid, clupanodonic acid.

These carboxylic acids can also be mixed with one another or as a mixture are used with other saturated or monoolefinic higher carboxylic acids, e.g. in the form of fatty acid mixtures of natural origin, such as cottonseed oil acids, Linseed oil acids, rapeseed oil acids, soy acids, fish oleic acids. But they can also do this Fat raw materials on which fatty acid mixtures are based, i.e. the triglycerides or their Customary transesterification mixtures with lower aliphatic alcohols in the invention Isomerization processes are implemented.

The isomerization of the compounds mentioned is preferably carried out under Protective gas carried out at normal pressure at the temperatures indicated above. the Response times are generally between: 0.5 and 12 hours. Reuse of the catalyst immediately after the reaction products have been distilled off is possible several times, provided that one is not in the range of very low catalyst concentrations works, since naturally also an inactivation of the catalyst by gradual Inhibition due to impurities is possible.

The isomerization reaction can generally in the absence of Solvents are carried out. In some cases, especially if it is is the isomerization of substances with a higher melting point, the application a solvent can be advantageous. In these cases such solvents are used used, in which the rhodium and ruthenium complexes are soluble.

Examples of suitable solvents are chlorobenzene, toluene and higher boiling ethers such as dioxane, diglycol dimlethyl ether.

The particular advantages of the method according to the invention are in its general applicability to a wide variety of oleine-mixed raw materials. There are numerous substances known, the isomerizations of olefinic Can create bonds; but there are mostly special ones for special problems Catalysts required.

In particular, the inventive method offers the advantage that Free fatty acids are also isomerized with the described catalyst combinations permit. Numerous substances are known that cause the isomerization of fatty acid esters allow. It is also known that alkali salts of fatty acids are inherently simple Way can be isomerized by alkali. Except that the free isomerized Fatty acids can only be obtained through further process steps the problem also arises for many of the catalysts described for isomerization the corrosion protection, for example with strong alkalis, iodine additives or else the problem that the isomerization catalysts are used in large menus will have to like E.g. that for the isomerization of fatty acid esters used iron pentacarbonyl. The conjugation of free fatty acids has so far been possible only in the presence of sulfur dioxide or nickel-sulfur or

.lickel-selenium compounds are carried out. That way conjugated diene fatty acids obtained, however, are unsatisfactory in quality.

The products of the process are due to the reactivity of conjunal bonds valuable intermediates for organic syntheses, especially oligomerization and polymerization processes. Fatty acids and fatty acid esters with conjugated double bond systems are particularly valuable raw materials in the paint sector.

The Rh and Ru complexes mentioned in the following examples were prepared as follows: I. [(C6H5) 3P] 3 RhCl Under a nitrogen atmosphere, 2 g Rh Cl3 3 H20 mixed with 100 ml of ethanol and the mixture 12 g of triphenylphosphine, dissolved in 400 ml of ethanol, added. The reaction mixture was refluxed for 1 hour held. The complex fell in the form of red-brown crystals with a melting point of 1570 C. (J. Chem. Soc. A, 1966, 1711).

II. [(C6H5) 3P] 2 RhCOCl In a solution of 1 g of Rh Cl3 3 H 20 in 60 ml of ethanol was passed in carbon monoxide at reflux temperature until the solution was light red in color. After adding 3 g of triphenylphosphine, dissolved in 100 ml of ethanol, the complex fell in the form of a yellow, crystalline product from, which had a melting point of 1950 C (Inorg. Synth. 8 (1966), 214).

III. (C8H14) 2 RhCl 1 g Rh Cl3 3 H20 and 2 ml cyclooctene were in 20 ml of methanol / water mixture (5: 1) are added. The reaction mixture was at 300 C kept, the complex gradually taking the form of a yellow-brown, crystalline Product deposited which had the melting point 150 ° C (Chem. Ber. 99 (1966), 3602).

IV. [(C2H5) 2S] 3 RhCl3 1 g Rh Cl3 3 H20 and 2.5 ml diethyl sulfide, dissolved in 100 ml of ethanol, the mixture was refluxed for 2 hours. Afterward the solution was concentrated in vacuo at room temperature. Here the divorced Complex in the form of orange-yellow crystals, which had a melting point of 1260 C. (J. Chem. Soc. 1965, 2627).

V. [(C6H5) 3P] 3 RuCl2 A solution of 1 g Ru Cl3 3 H2O in 200 ml methanol 6 g of triphenylphosphine were added and the mixture was refluxed for 3 hours. Of the The complex precipitated out as a brown, crystalline product (J. Inorg. & Nucl. Chem. 28: 945 (1966)).

vI C (C2H5) 2S] 3 RuCl3 0.5 g Ru Cl3 3 H20 and 2 ml diethyl sulfide, dissolved in 30 ml of ethanol were refluxed for 1 hour. The solution was then concentrated in vacuo at room temperature. Here the complex differed in shape red crystals (J. Chem. Soc. 1965, 2627).

VII. [(C6H5) 3P] 3 RhSnCl3 A solution of 1 g of Rh Cl3 3 3 H20 and 7.5 g Sn C12 2 H20 in 200 ml ethanol was mixed with 30 g triphenylphosphine, dissolved in 80 ml of ethanol, added. The reaction mixture was refluxed as long as until the resulting precipitate had turned a dark red-brown color (approx. 1h) (J. Chem.

Soc. 1964, 5176).

In the following the abbreviations O3P for (C6H5) 3P and Et2S for (C2H5) 2S related.

Example 1 In a 100 ml flask fitted with a reflux condenser, stirrer and gas inlet device was provided, 16 ml of soy acid methyl ester (54 % Linoleic acid methyl ester, 28% oleic acid methyl ester, 5% linolenic acid methyl ester, 8 g methyl palmitate, 4% methyl stearate, remainder C14u # C20 methyl ester), 0.1 g (3P) 3 Rh Cl and 0.2 g Sn Cl2 # 2 H20 combined under a nitrogen atmosphere. The reaction mixture was heated with stirring to 1900 C and one hour at this The temperature was then maintained by distillation of the fatty acid ester mixture the catalyst combination separated and examined by UV spectroscopy. From the The conjudia content determined was - based on the linoleic acid ester content of the Starting mixture - a degree of isomerization of 71.5%.

Examples 2-5 In an analogous manner, soybean ester was isomerized in the presence of the catalyst combinations mentioned below. Example amount of catalyst combination react. React. Isome Soy temp. Time ris- ester ° C ml degree % 2 12 0.1 g (O3P) 3Rh Cl - 0.05 g CuCl2 140 15 31.5 3 14 0.1 g (O3P) Rh CO Cl - 0.25 g SnCl2 # 2H2O 150 15 72.0 4 12 0.1 g (C8H14) 2Rh Cl - 0.05 g SnCl2 # 2H2O 100 8 31.0 5 12 0.1 g (O3P) 3Ru Cl2 - 0.1 g SnCl2 # 2H2O 150 12 32.5 Comparative experiments The experiments according to Examples 1 and 3-5 were repeated, omitting the cocatalysts. The degrees of isomerization determined were (in the corresponding order): 8%, 6%, 2%, 3%.

Another experiment in which 10 ml of soy ester with 0.2 g of Sn Cl2 # 2 H2O were kept at 140 ° C. for 15 hours, resulted in a degree of isomerization of 2%.

6-10.) In the procedure according to Example 1, soy acid (composition corresponding to the methyl ester used in Example 1) was isomerized in the presence of various catalyst combinations. Example amount of catalyst combination react. React. Isome Soy temp. Time ris- ester ° C ml degree % 6 30 0.15 g (O3P) 3Rh Cl - 0.25 g SnCl2 # 2H2O 150 15 60.5 7 20 0.2 g (O3P) 2Rh CO Cl - 0.1 g SnCl2 # 2H2O 100 12 75.0 8 10 0.1 g (Et2S) 3Rh Cl3 - 0.06 g SnCl2 # 2H2O 140 15 28.0 9 10 0.1 g (Et2S) 3Ru Cl3 - 0.1 g SnCl2 # 2H2O 140 15 26.0 10 10 0.1 g (O3P) 3Rh SnCl3 - 0.1 g SnCl2 # 2H2O 140 15 48.0 +) based on the linoleic acid content of the starting material 11. - 14.) In a test procedure analogous to Example 1, the olefinic compounds mentioned below were isomerized in the presence of the catalyst combination (O3P) 3 RhCl - Sn Cl2 # 2 H2O. E.g. olefinic compound amount amount react. React. Isome (O3P) 3 SnCl2 temp. Time ris- Rh Cl 2 H2O gg ° C h% 11 5 ml linoleic acid +) 0.1 0.05 100 12 76 12 10 ml 1-butene-2,4-dicarbon dimethyl acid 0.1 0.1 120 16 90 13 6 ml allylacetic acid 0.1 0.1 110 16 97.5 14 10 ml 2,5 - heptadienoic acid 0.15 0.15 120 1 82 +) 70% strength Example 15 0.1 L (3P) 3 Rh Sn C13 were added to 12 ml of decatriene 1.4.9 under a nitrogen atmosphere and the reaction mixture was heated to 110 ° C. for 15 hours. The UV spectroscopic and gas chromatographic examination of the product distilled off from the catalyst showed that 84.5% of the starting olefin had been isomerized to decatriene-1.6.8.

Example 16 In a solution of 1 m 1 of vinyl acetic acid in 10 ml of benzene 0.1 g of (3P) 3 Rh Cl and 0.1 g of Sn C12 2 H20 were added under a nitrogen atmosphere and the mixture is heated to 600 ° C. for 5 hours. The separated from the catalyst by distillation Product was examined by gas chromatography. The vinyl acetic acid used was 90% isomerized to crotonic acid.

Example 17 75 ml linoleic acid (composition 51% linolenic acid, 17% linoleic acid, 22% oleic acid, remainder sat. C16 - C24 acids) were under nitrogen 0.9 g of (O3P) 2 Rh CO Cl and 0.5 g of Sn Cl2 # 2 H2O were added and the reaction mixture Heated to 140 ° C. for 18 hours.

The fatty acids were then separated from the catalyst by distillation and examined by UV spectroscopy. The conjugated content of the reaction product Serving was Q2%, conjugated trienes 10.5%, based on linolenic acid + linoleic acid respectively.

Linolenic acid.

Example 18 In a modification of the procedure according to Example 1, Soy acid methyl ester in the presence of a catalyst complex combination formed in situ isomerized. 16 ml of soy acid methyl ester were initially charged and under a nitrogen atmosphere 0.05 g of Rh C13 3 H20, 0.1 g of triphenylphosphine and 0.05 g of Sn Cl2 2 H20 were added. The mixture was heated to 1400 ° C. and held at this temperature for 15 hours. Processing and investigation of the resulting product as in example 1.

The degree of isomerization, based on the linoleic acid ester content of the starting material, was 24.5, N, 0 Example 19 The multiple reusability of the catalyst combinations emerges from the following experiments: 75 ml of soy acid were added under a nitrogen atmosphere 0.9 g of (3P) 2 Rh CO Cl and 0.5 g of Sn C12 2 H20 were added and the mixture was stirred Heated to 1400 C for 30 hours. The product distilled off from the catalyst had a degree of isomerization of 68.2%. The distillation residue was again with 30 ml of soy acid are added and the mixture is kept at 1500 C for 15 hours.

The degree of isomerization of the product resulting from the distillation was 76.5%. Another 30 ml of soy acid were added to the distillation residue and heated to 1500 C for 40 hours. A fatty acid mixture was obtained by distillation obtained with the degree of isomerization 72%.

Similar results were obtained with a catalyst combination of 0.2 g (3P) 3 Rh Cl and 0.1 g Sn Cl2 2 H2O were obtained.

Claims (7)

P a t e n t a n 8 p r a c h e 1. Process for catalytic isomerization, olefinically unsaturated he compounds with the formation of structures with conjugated double bonds, characterized in that complex compounds are used as isomerization catalysts of mono- and trivalent rhodium and / or bivalent and trivalent ruthenium in Combination with metal halides from the class of the chlorides and / or bromides of Copper (II), mercury (II) aluminum, tin (II) and (IV), antimony (III), bismuth (III) can be used. 2. The method according to claim 1, characterized in that the rhodium and / or ruthenium complexes contain halogen ligands. 3. The method according to claim 1 - 2, characterized in that the Rhodium and / or ruthenium complexes contain chlorine ligands. 4. The method according to claim 1-3, characterized in that the Cocatalyst is a chloride. 5. The method according to claim 1-4, characterized in that the The cocatalyst is a chloride of tin, in particular the compound Sn Cl2 2 H20. 6. The method according to claim 1-5, characterized in that the Catalyst combinations rhodium and / or fluthenium complex and cocatalyst im Molar ratio 1: 1 to 1:15, preferably 1: 2 to 1:10. 7. The method according to claim 1-6, characterized in that as olefinically unsaturated compounds containing polyunsaturated 6 -24 carbon atoms Carboxylic acids are used in the form of their esters and especially in the form of the free acids will.