DE1180362B - Process for the catalytic isomerization of olefins - Google Patents

Description

Process for the catalytic isomerization of olefins It is known to use organometallic mixed catalysts for the polymerization of α-olefins. Such mixed catalysts generally consist of a compound of a transition metal and an organometallic compound of elements from I. to III. Main group of the periodic table. As particularly effective for the production of high molecular weight poly-a-olefins Mixtures of titanium (3) chloride and organoaluminum compounds such as Diethyl aluminum chloride.

It is also known that mixtures of titanic acid esters or the analogous zirconium compounds with trialkylaluminum ethylene preferably to butene-1 dimerize.

The subject of this patent is now a process for catalytic Isomerization of olefins by shifting double bonds. It was found, that mixtures of a) alcoholates, phenolates and enolates of metals of IV. to VII. subgroup of the periodic table and b) dialkyl hydrides and / or trialkyl compounds of aluminum or its atherates are particularly effective catalysts for isomerization of olefins by shifting double bonds, surprisingly no substantial polymerization of the olefins is observed.

The compounds of Metals of subgroups IV to VII of the periodic table correspond to the general ones Formula McOm (OR) nXp where R is optionally represented by functional groups that behave inertly under the reaction conditions, substituted aliphatic or aromatic hydrocarbon radical, in particular also by oxygen-containing functional groups substituted alkyl, aryl, aralkyl or alkenyl, X halogen, preferably bromine and especially chlorine, or else alkyl or cycloalkyl, for example Cyclopentadienyl and m, n and p represent integers, of which m = 0 or 1, n can be an integer other than 0, p = 0, 1 or 2 and the relationship 2m + n + p indicates the valence of the metal Me.

Compounds of the transition metals of subgroups IV to VII of the periodic table which are suitable for the catalyst mixture have proven, inter alia, their alkoxy compounds, phenolates, hydroxycarboxylic acid ester compounds and enolates, in particular those derived from compounds with a 5-diketo structure, which may still carry halogen on the metal the acetylacetonates, benzoylacetonates, dibenzoylmethane and acetoacetic ester compounds. Individual compounds that may be mentioned are: chromium trisacetylacetonate Cr (AA) 3, Vanadium trisacetylacetonate V (AA) 3, vanadyl bisacetylacetonate VO (AA) 2, chlorovanadyl bisacetylacetonate VO (AA) 2CI, dichloro vanadyl acetylacetonate VO (AA) CI2, titanium trisacetylacetonate Ti (AA) 3, zirconium tetrakisacetylacetonate (AA) 4, chlorine zirconium trisacetylacetonate Zr (AA) 3CI, manganese trisacetylacetonate Mn (AA) 3, chromium trisbenzoylacetonate Cr (BA) 3 Titanium tetraethylate Ti (OCaH5) 4, -tetrapropylate, -tetraisopropylate, -tetrabutylate, -tetraisobutylate, -tetraamylate, -tetradecylate, cyclopentadienyltrimethoxy titanium, cyclopentadienyl-triethoxy-dimethyl-dimethoxytitanium; Zirconium tetraethylate Zr (OC2Hs) 4, -tetrapropylate, -tetraisoamylate and others, orthovanadic acid trimethyl ester VO (OCHs) 3, -triethyl ester, -tripropyl ester, -triisopropyl ester, -tributyl ester, -triisobutyl ester, formula-trihexyl ester, VO, etc. 2CI and the like, however, in general - especially with otherwise the same empirical formula - the compounds of those transition metals of subgroups IV to VII of the periodic table which belong to the fourth period are preferred as the most suitable catalyst components, in particular the orthotitane esters Ti (OR) 4 and vanadium esters.

The dialkyl hydrides can be used as organometallic compounds and / or the trialkyl compounds of aluminum and / or their atherates, such as trimethyl, Triethyl, tripropyl, tri-n-butyl, triisobutyl, tri-n-hexyl, triisohexyl, tri-n-octyl, Triisooctylaluminum et al. as well as diethyl aluminum hydride, diisobutyl aluminum hydride etc., as well as their atherates, tetrahydrofuranates, dioxanates, glycol etherates, diethylene glycol dimethyl etherates etc. As particularly suitable catalyst components for olefin isomerization such aluminum compounds have been found to be the highly branched alkyl radicals wear, for example triisobutylaluminum.

The active catalyst is created when the two catalyst components are mixed, where z. B. in the case of the titanium and vanadic acid esters with gas formation reddish-brown to black-brown solutions arise, which the transition metal partly in a lower Value level included.

The individual components of the mixed catalyst, for example Titanium acid tetraalkyl ester, orthovanadic acid trialkyl ester, chromium trisacetylacetonate, Triethylaluminum, or triisobutylaluminum, are by themselves with the for that Isomerization processes characterizing low temperatures are entirely catalytic ineffective.

The concentration of the compound MeOm (OR) Xp in the reaction mixture is expediently chosen in the range from 1 to 100 mmol / l, preferably from 10 to 50 mmol / l Overall mix.

The molar mixing ratio of transition metal to aluminum is expediently between 1: 0.5 and 1:10, preferably between 1: 2 and 1: 8.

Room temperature is suitable as the reaction temperature, but it can Process generally at temperatures between about -20 and + 150 ° C, preferably between 0 and 80 ° C.

The process can be carried out at atmospheric pressure, at excess pressure or Perform negative pressure. The use of overpressure is with low-boiling, under Normal conditions of gaseous olefins indicated.

In the case of high-boiling reactants, the use of Recommend negative pressure, because then z. B. the olefin can be continuously distilled off, without having to use excessively high temperatures.

The process according to the invention can be applied to all olefins which occur in at least two isomeric forms, which are distinguished by a different Differentiate the position of their double bonds. These include straight-chain olefins at least 4 carbon atoms with an internal or terminal double bond, e.g. B. butene-1, Butene-2, n-pentenes, n-hexenes, n-heptenes, n-decenes, n-hexadecenes, etc., branched Olefins with an internal or terminal double bond, e.g. B. methyl-butene, methyl-penten, Methyl-hexene, dimethyl-butene, dimethyl-pentene, 2-ethyl-butene-1, etc.; arylated Alkenes such as AllyI-benzene. Phenyl butenes, phenylpentene, etc; cyclic olefins such as Methyl-cyclopentene, phenyl-cyclohexene, terpene hydrocarbons such as a- and A-pinene, Dipentene, etc., olefins with several non-conjugated double bonds, such as pentadiene-1, 4-octadiene-1,5, octadiene-1,7, limonene, B-terpinene, etc.; halogenated olefins, as long as they do not react with trialkylaluminum, e.g. B. 5, 5, 5-trifluoropentene-1, 2-Trifluoromethyl-pentene-2, 4-chloro-butene-1, 5-chloro-pentene-2 etc. In addition to individual Olefin isomers can of course also be mixtures of different isomers can be used.

To carry out the process, the catalyst components are dissolved expediently individually in different vessels in the olefin to be isomerized and then mixes the solutions thus obtained. One avoids this way of working the later separation of foreign substances. But it is also possible to have the reaction to be carried out in any diluent, provided that these are under the reaction conditions behave inertly towards the reactants. As an inert diluent for example aliphatic, cycloaliphatic and aromatic hydrocarbons are suitable or hydrocarbon mixtures, certain inert chlorinated hydrocarbons such as Chlorobenzenes and ethers, for example those mentioned above for atherate formation Compounds and the like. The boiling point of the solvent is expediently chosen so that easy separation of the reaction product is ensured.

Catalysts for the isomerization of olefins are known. Compared to these known isomerization catalysts show the new organometallic Mixtures, however, have a number of significant advantages: Due to their solubility in the to isomerized olefins, the reaction can be practically in all cases in perform homogeneous solution, which is particularly beneficial to the isomerization rate affects. The catalyst mixtures used according to the invention are still like this active that in their presence the desired isomerizations are generally already at Room temperature and even at considerably lower temperatures with sufficient run at high speeds, while those previously used for this purpose known catalysts that enable isomerizations only at temperatures which are usually well above 100 ° C. A major benefit that is under is also favored by the low isomerization temperatures, also particularly consists in the fact that the catalyst mixtures used according to the invention almost exclusively favor the desired double bond isomers, while isomerizations, which change the carbon skeleton of the olefins do not occur. Step in the same way even in the present process, there are no significant olefin polymerizations, therefore no resinified products are obtained.

It is also essential that the catalysts used do not Addition reactions with the olefins tend and these for example in alcohols, Converted alkyl halides or other undesirable by-products. Finally runs the isomerization reaction also takes place without corrosion of the vessel walls, since the mixtures contained neither water nor acids.

Examples 1 to 17 The tests were made in thick-walled, pressure-resistant sealable 200 ml bottles with magnetic stirrer. One mixed at 0 ° C rapidly with stirring a) 25 ml of the olefin in question with b) 25 ml of a Solution of triisobutyl orthovanadate in a saturated hydrocarbon fraction the boiling range 190 to 210 ° C, their respective concentration given in table 1 and c) 20 ml of a trialkylaluminum solution in the same hydrocarbon fraction, the vanadium-aluminum ratio being constant = 1: 3. The mixes remained in the thermostat at 20 ° C. According to the given in Table 1 During the experiment, the olefins were separated off and analyzed (gas chromatography and UR spectrum).

Table 1 Concentrate result tration of No. Olefin Purity Vanadium Al compound Isomeric duration compound sation obtained isomers % mmol / I hours% 1 n-butene-1> 99.9 25 (C2H5) 3Al 0.25 82 trnas-Bu-2: 19%, cis-Bu-2: 63% 2 25 (i-C4H9) 3Al 0.25 95 trans-Bu-2: 28%, cis-Bu-2: 67% 3 n-pentene-1 98.5 50 (C2H5) 3Al 5 96 pentenes-2: 96% (cis 96 ° / o (cis: 1) 4 n-hexene-21> 99 90 (C3H5) Al 5 99 cis-He-2: 30%, trans-He-2: 69% 5 n-Hepten-1 95 50 (C2H5) 3Al 5 99 Hepten-2: 92%, Hepten-3: 7% 6 95 50 (i-C4H9) 3AI I 99 Hepten-2: 900 / o, Hepten-3: 9% 7 n-hepten-3> 99 50 (i-C4H9) 3Al 1 19 hepten-2: 19% 8> 99 50 (i-C4H9) 3Al 5 40 Hepten-2: 40% 9 3-methyl-butane-1> 99.9 25 (C2H5) 3Al 35 2-MB-1: 6, 0%, 2-MB-2: 29% 10> 99.9 50 (C2H5) 3Al 0.5 20 2-MB-1: 3, 0%, 2-MB-2: zozo 11> 99.9 50 (i-C4H9) 3Al 1 51 2-MB-1: 4, 0% 2-MB-2: 47% 12> 99, 9 50 (CHs) AI 5 6 2-MB-2: 6% 13 2-methyl-pentene-1 99 50 (C2H5) 3Al 5 5 2-MP-2: 5 ° / 0 14 99 50 (i-C4H9) 3Al 5 64 2-MP-2: 62`` / o, 4-MP-2: 2% 15 4-methyl-pentene-1> 99 90 (C2H5) 2Al 10 48 4-MP-2: 46% 16 4-methyl-pentene-2> 99.5 90 (C2H5) 3Al 10 8 2-MP-2: 8% 17 2-Ethyl-butene-1 96 90 (i-C4H9) 3Al 5 62 3-MP-2: 62% Examples 18 to 20 25 ml of a solution of 3.5 mmol of triisobutyl orthovanadate in decahydronaphthalene, 25 ml of 3-methyl-butene-1 (purity> 99.9%) and 20 ml of a solution of 10.5 mmol of trialkylaluminum in decahydronaphthalene were used stirred rapidly at 0 ° C. The reaction vessel was then closed pressure-tight and the reaction was allowed to proceed in a thermostat at 40.degree. At the end of the reaction time given in Table 2, the olefin mixture was separated off and analyzed. The results are compiled in Table 2: Table 2 No. Al compound reaction time isomerization Hours % 18 (CH3) 3AI 1 5 19 (C2H5) 3Al 1/2 31 20 (C2H5) 3Al 5 72 Example 21 25 ml of a solution of 1.0 ml (3.5 mmol) of orthovanadic acid triisobutyl ester in a saturated hydrocarbon fraction with a boiling range of 190 to 210 ° C, 25 ml of 3-methyl-butene-1 (degree of purity> 99.9%) and heated a solution of 17.5 mmol of triisobutylaluminum in 20 ml of the above hydrocarbon fraction. after mixing at 0 ° C for 2 hours at 60 ° C. The isomerization proceeded to 99.5%; 90.2% of 2-methyl-2-butene and 9.3% of 2-methyl-1-butene were obtained.

Example 22 Example 21 above was repeated with the modification that that one at. Place of the vanadic acid ester 3, 5 mmol titanium tetraisopropylate used, and obtained after 5 hours at 60 ° C. a 65% isomerization: 2-methyl-butene-1 : 44.5%; 2-methylbutene-2: 20, 5% The 2-methyl-butene-1 can be obtained from the reaction mixture of bp 31 ° C by fractional distillation on a powerful column be separated.

Example 23 Example 21 is repeated with 3.5 mmol of titanium tetra-n-butoxide instead of the vanadic acid ester and obtained 47% isomerization after 5 hours at 60 ° C : 2-methyl-butene-1: 17%; 2-methyl-butene-2: 30%.

Example 24 A series of tests were carried out under otherwise identical conditions, but the vanadium / aluminum ratio varied. The individual batches used here, each with a total volume of 70 ml, each contain 1.0 ml of triisobutyl orthovanadate (3.5 mmol) and 25 ml of 3-methyl-butene-1, as a diluent a saturated hydrocarbon fraction with a boiling point of 190 to 210 ° C and finally Triethylaluminum, the amount of which varied from batch to batch in such a way that the aluminum-vanadium ratio desired in each case was achieved. The results of this series of tests, which were obtained after standing at 20 ° C. for 5 hours, are shown in the graphic illustration below. It turns out that maximum values for the isomerization were found when the aluminum to vanadium ratio is between 3 and 4 under otherwise identical conditions.

AI: V ratio example 25 25 ml of a solution of 1, 0 ml (3, 5 mmol) triisobutyl orthovanadate in a saturated hydrocarbon fraction from the boiling range 190 to 210 ° C, 25 ml of 3-methyl-butene-1 (purity> 99.9%) and a solution of 1.5 ml of diethylaluminum hydride in 20 ml of the above hydrocarbon fraction were mixed at 0 ° C and then left to stand at 20 ° C for 5 hours. Isomerization : 52 ° / o. 2-methylbutene-2: 48.5 ° lo; 2-methyl-butene-1: 3.5%.

For example, 26 25 ml of a solution of 3.5 mmol of orthovanadic acid triisobutyl ester in a saturated hydrocarbon fraction from the boiling range 190 to 210 ° C, 25 ml of 2,3-dimethyl-butene-1 (95%) and a solution of 10, 5 mmol of triisobutylaluminum in 20 ml of the above hydrocarbon fraction were mixed at 0 ° C and then Isomerized at 60 ° C. for 1 hour.

19% 2,3-dimethyl-butene-2 was obtained.

Example 27 1.0 ml of triisobutyl orthovanadate was dissolved in 20 ml of ß-pinene and added a solution of 2.0 ml of triethylaluminum with stirring in 20 ml ß-pinene added. The brown mixture obtained was heated with the exclusion of air 10 hours at + 60 ° C and received 60 to 65% a-pinene in a mixture with -pinene.

Example 28 A solution of 1.0 ml of tri-n-butyl orthovanadate was mixed in 40 ml of 2-methyl-pentene-1 with a solution of 1, 5 ml of triethylaluminum in 30 ml 2-methyl-pentene-I and heated the mixture for 5 hours to + 40 ° C. Then was Quenched by cooling and the olefin is distilled off in a cold trap under reduced pressure. The yield was 95%. The analysis showed 70% 2-methylpentene-2, 3% 4-methyl-pentene-2, Residue 2-methylpentene-1. The decomposition of the distillation residue did not result in any isolable amount of high molecular weight substances.

Example 29 25 ml of a solution of 2.0 ml of triisobutyl orthovanadate were mixed in diethylene glycol dimethyl ether, 20 ml of Hepten-1 and 25 mol of a solution of 3, 5 ml of triethylaluminum in the same ether and heated the red-brown to dark-brown Mix 10 hours at + 60 ° C. The usual work-up yielded a heptene mixture from 8% hepten-1, 86% hepten-2 and 3% hepten-3. So the isomerization proceeded at 89 ° / o.

Example 30 25 ml of a solution were mixed with one another at 0 ° C of 2.0ml of triisobutyl orthovanadate in a saturated hydrocarbon fraction from the boiling range 190 to 210 ° C, 25 ml of 3-methylbutene-1 (purity> 99.9%) and a solution of 3.5 ml of triethylaluminum and 3.0 ml of tetrahydrofuran in 20 ml of the above Hydrocarbon fraction. The red-brown clear mixture was then 20 hours heated to + 60 ° C. Isomerization: 98%; 2-methylbutene-2: 85%; 2-methyl-butene-1 : 13%.

Examples 31 to 34 25 ml of a solution of 7.0 mmol of transition metal compound (see Table 3) in xylene, 25 ml of 3-methyl-butene-1 (purity> 99.9%) and 20 ml of a solution of 3.0 ml (21.0 mmol) of triethyl aluminum in xylene were at 0 ° C mixed quickly and then immediately warmed to 20 ° C for 20 hours.

Table 3 Transitional result,% Color of No. Metal Isomeri- 2-methyl- 2-methyl- sation butene-2 butene-1 31 Cr (AA) red-brown 23 23 0 32 V (AA) 3 red-brown 15 13 1, 5 33 VO (AA) 2 red-brown 32 29 3.0 34 VO (AA) 2Cl red-brown 8 7.3 0.5 Example 35 1.25 g (3.5 mmol) of crystalline manganese trisacetylacetonate, 25 ml of absolute xylene and 25 ml of 3-methyl-butene-I were mixed with stirring at 0 ° C. and a solution of 17.5 mmol of triisobutylaluminum was then added in 15 ml of absolute xylene. After heating at 60 ° C. for 5 hours, the starting olefin was isomerized to the extent of 49%: 2-methyl-2-butene: 38%; 2-methyl-butene-1: 11%.

Examples 36 to 43 A series of experiments was carried out under otherwise identical conditions and only the alkyl groups in the orthovanadic acid ester [VO (OR) 3] were varied. The respective mixtures of 3.5 mmol of orthovanadic acid trialkyl ester in 25 ml of a saturated hydrocarbon fraction boiling from 190 to 210 ° C, 25 ml of 3-methyl-1-butene (purity> 99.9 ° / 0) and 10.5 mmol of triisobutylaluminum in 20 ml of the above hydrocarbon fraction were heated to 60 ° C. for 60 minutes. The test results are compiled in Table 4: Table 4 2-methyl-2-methyl- No. Alkyl group R butene-1 butene-2 %%% 36 C2H5 90 9 81 37 n-C3H7 90 9 81 38 i-CsH 92, 5 9, 5 83 39 n-C4H9 98 7.5 90.5 40 i-CtHs86, 5977, 5 41 sec.-CtHg771166 42 tert-C4Hs 51 8 43 43 n-C5H11 96 9 87 Examples 44 to 51 A series of experiments with catalysts made from various titanic acid esters Ti (OR) 4 and triisobutylaluminum was carried out under the same external conditions. In each case 3.5 mmol of the tetraalkyl orthotitanate in question were mixed in 25 ml of a saturated hydrocarbon fraction boiling from 190 to 210 ° C., 25 ml of 3-methyl-1-butene (purity> 99.9%) and 10.5 mmol of triisobutylaluminum in 20 ml of the hydrocarbon fraction mentioned, heated the individual batches to 60 ° C. for 5 hours and obtained the results compiled in Table 5.

Table 5 Isomerization of 2-methyl-2-methyl- No. Alkyl group R butene-1 butene-2 %%% 44 CH3 55.5 15 40.5 45 C? H5 61, 5 25, 5 36 46 n-C3H7 45 22, 5 22, 5 47 1-C3H7 54 39, 5 14, 5 48 n-C4H9 47 20, 5 26, 5 49 t-CiH9 29, 5 16-13, 5 50 sec.-C4H9 53, 5 36, 5 17 51 terL-C4Hs 23, 5 11, 5 12 Example 52 A solution of 1.0 ml (3.5 mmol) of tri-n-butyl orthovanadate in 25 ml of a saturated hydrocarbon fraction with a boiling point of 190 to 210 ° C., 25 ml of 4-methylpentene-1 (99% ig) and a solution of 17.5 mmol of triisobutylaluminum in 20 ml of the above hydrocarbon fraction. The mixture was heated to 60 ° C. for 5 hours. 100% isomerization occurred. The isomerization product consisted of 96% 4-methyl-2-pentene and 4% 2-methyl-2-pentene.

Claims (5)

Claims: 1. Process for the catalytic isomerization of Olefins by shifting double bonds, characterized in that one the olefins with mixed catalysts from a) metal compounds of subgroups IV. to VII of the periodic table of the general formula Meom (OR), Xp wherein R is an optionally substituted aliphatic or aromatic hydrocarbon radical, X halogen, Alkyl or cycloalkyl, m the numbers 0 or 1, p the numbers 0, 1 or 2, n can be an integer other than 0 and the relation 2m + n + p the valence of the metal Me, and b) aluminum dialkyl hydrides and / or aluminum trialkyl compounds and / or their atherates, optionally in the presence of an inert diluent, treated. 2. The method according to claim 1, characterized in that as Catalyst components of the formula MeOm (OR) nXp compounds used in which the metal Me belongs to the fourth period of the periodic table. 3. The method according to claim 1, characterized in that as Catalyst is a mixture of an orthotitanic acid ester and an aluminum trialkyl compound used whose alkyl group is highly branched. 4. Process according to Claims 1 to 3, characterized in that the concentration of the transition metal compound used as a catalyst component 10 to 50 mmol, based on 11 of the total mixture. 5. Process according to Claims 1 to 4, characterized in that the molar mixing ratio of transition metal to aluminum is between 1: 2 and 1 : 8 is.