DE1194410B - Process for the preparation of predominantly alicyclic oligomers of 1,3-dienes - Google Patents

Description

Process for the preparation of predominantly alicyclic oligomers of 1,3-dienes Oligomers of 1,3-dienes are known to have increased recently Importance as intermediate products for plastics as well as starting materials for others chemical reactions obtained. There are catalysts for the oligomerization of 1,3-dienes have become known, which contain titanium, chromium, iron, cobalt or nickel.

In some of the known processes that use nickel catalysts work, one goes in the preparation of the catalyst of nickel (II) compounds which are reduced in the presence of an electron donor. According to the Belgian Patent specification 598 363 uses metal hydrides or organometallic reducing agents Links. In the German Auslegeschrift 1126 864 the use of certain Metals described as reducing agents. The processes give good yields of oligomers, in particular of cyclic dimers. However, they lack that one is either difficult to handle or sensitive to oxygen and moisture Must use substances or, if the reduction takes place in a heterogeneous system, the catalyst components must mix intensively for a long time.

In the processes mentioned, the nickel (II) compounds are in catalytically active nickel (0) compounds transferred. One has already tried to avoid this reduction and in the catalyst production directly from nickel (0) compounds to go out. Used in the process of French patent 1,295,072 one catalysts, which by reacting a carbon monoxide-free organic nickel (0) compound, such as nickel (0) -bis-acrylonitrile or nickel (0) -bis-acrolein, with an ester the phosphorous acid can be obtained. Used according to another older suggestion one catalysts which arise from the components mentioned in the presence of butadiene.

The carbon monoxide-free organic nickel (0) compounds are from nickel tetracarbonyl and o -unsaturated nitriles or aldehydes, such as acrylonitrile or acrolein.

Used in older 1,3-diene oligomerization processes one nickel carbonyl catalysts in which one or two of the carbonyl ligands are replaced by a compound of trivalent nitrogen or phosphorus. Such compounds are easily formed from nickel tetracarbonyl and the mentioned, one or two compounds displacing carbon monoxide ligands (cf. German patents 881 511 and 951 213). However, the yields are unsatisfactory. They amount to according to the examples of the patents mentioned, in the best case 44%. the Yields can be achieved by choosing particularly favorable reaction conditions (see US Pat. No. 3,004,081), by adding isobutylene or diisobutylene (see.

USA.-Patent 2,972,640) or of cycloaliphatic dienes (cf. U.S. Patent 2,964,515). However, reaction rates are relatively low, so that a good space-time yield cannot be achieved.

The Belgian method gives a better space-time yield Patent specification 607 397, in which one uses a carbonyl-containing nickel catalyst, in which there are three arsenite or phosphite residues. Such - complex compounds however, they are no longer as easily accessible because of the replacement of the third carbon monoxide ligand arsenite or phosphite no longer takes place as easily as displacement the first two ligands.

Finally, according to French patent specification 1,290,659, it is used a catalyst composed of nickel tetracarbonyl and a hydride or an organometallic Connection is established. However, these catalysts are not particularly effective because as byproducts of the catalytic oligomerization is formed in yields of 24 up to 83% l-vinylcyclohexene (3), the reaction product of thermal Diels-Alder dimerization.

It has now been found that oligomers of 1,3-dienes from the 1,3-dienes and optionally from olefins in the presence of one from nickel tetracarbonyl Available catalyst can advantageously be prepared if you use a catalyst used, which is made from nickel tetracarbonyl and a polyene posed was, with one during the mutual action of the catalyst components kept the concentration of carbon monoxide low.

In the process according to the invention, good yields are obtained 1,3-diene oligomers, especially in continuous operation. For catalyst production becomes the cheapest of all nickel compounds, namely nickel tetracarbonyl, used. Although the catalyst is only used in a small amount, achieved a high reaction rate and thus higher space-time yields. It was surprising that nickel tetracarbonyl was effective upon exposure to a polyene Oligomerization catalyst could be obtained by looking at the concentration of carbon monoxide kept low. Adapted from H. W. B. R e e d, Journal of the Chemical Society (London), vol. 1954, p. 1934, para. 4, namely arises from nickel tetracarbonyl and the 1,3-diene to be reacted is not an effective oligomerization catalyst.

In the process according to the invention, predominantly cyclic ones are obtained Homooligomers of 1,3-dienes, especially dimers and trimers, and cyclic or open-chain mixed oligomers of 1,3-dienes and olefins. Remarkably, arise in the case of mixed oligomerization, there are practically no products from 1 molecule at all of 1,3-diene and 1 to 3 molecules of olefin, which are from the U.S. patent 2,599,249 are known. Rather, mixed oligomers consisting of at least two molecules are obtained of 1,3-diene and a varying number of molecules of monoolefin.

The 1,3-dienes that can be converted according to the new process are usually open-chain or cyclic hydrocarbons with conjugated Double bonds, the 1,3-diene structure wholly or partly in a cycloaliphatic Ring can be incorporated. Suitable 1,3-dienes include: butadiene (1,3), Isoprene, 2,3-dimethylbutadiene (1,3), 2-ethylbutadiene (1,3), pentadiene (1,3), hexadiene (1,3), Hexadiene (2,4), cyclohexadiene (1,3) and vinylcyclohexene (1). Also hexatriene (1,3,5), 3-methylheptatriene (1,4,6) and octatriene (1,3,6) are useful. The preferred In addition to butadiene, 1,3-dienes are open-chain dienes with 5 to 8 carbon atoms. 1,3-dienes that have at least one terminal double bond are special well suited. The starting materials do not need to be pure, they can also be used in a mixture with other substances which are inert under the conditions of the process will.

The preferred monoolefins are alkenes having 2 to 12 carbon atoms and terminal double bond. Examples of these are: ethylene, Propylene, butene (l), hexene (l), isobutene, octene (l), dodecene (l) and vinylcyclohexane.

You can use pure or technical catalysts in the production of catalysts Run out of nickel tetracarbonyl.

The nickel tetracarbonyl only needs a small amount, for example between 5 and 0.0005 percent by weight, based on the 1,3-diene to be reacted, applied To be preferably used a catalyst concentration between 0.1 and 0.001 percent by weight.

Suitable polyenes include, for example, cyclooctadiene- (1,5) and called cyclododecatriene- (1,5,9). It is particularly advantageous to use 1,3-diene, that in the following actual environment setting is to be oligomerized. on in this way no foreign constituents are introduced into the reaction mixture. It is true that small amounts are used in the preparation of the catalyst Polyene has a remarkable effect, for example with 1 mole per mole of nickel tetracarbonyl. However, it is recommended to use a considerable excess of the unsaturated compound apply, for example 4 to 400 moles per mole of nickel tetracarbonyl. The co-use An inert solvent in the preparation of the catalyst is particularly recommended when you only use the unsaturated compound in a relatively small amount used. Suitable inert solvents include aliphatic and cycloaliphatic ones and aromatic hydrocarbons such as hexane, heptane, cyclohexane, benzene, cyclooctane, between about 60 and 200 "C boiling hydrocarbon mixtures from petroleum and Ether, tetrahydrofuran, dioxane and diisopropyl ether.

The catalyst is made from nickel tetracarbonyl and the ones mentioned unsaturated compounds at temperatures that are advantageously between 0 and 200 "C, in particular between 40 and 150 ° C. The pressure is generally directed according to the vapor pressure of the nickel tetracarbonyl and the unsaturated compound the temperature in question. So one generally works under atmospheric pressure or use elevated pressures, e.g., up to 25 atmospheres.

It is an essential feature of the method according to the invention, that the concentration of carbon monoxide in the action of the catalyst components keeps low. The carbon monoxide is expediently removed continuously or over time at the time from the mixture of effects. Presumably is due to the unsaturated compound Carbon monoxide is at least partially displaced from the nickel carbonyl.

This process is evidently promoted by the removal of the carbon monoxide. But you can not just by removing the carbon monoxide from the action mixture keep the concentration of carbon monoxide low. Another way, the similar one Brings results, consists in that one the nickel tetracarbonyl in low concentration, preferably less than 0.1 percent by weight, based on the 1 to be reacted , 3-diene, applies. In the case of continuous operation, this is in the unit of time reacted amount of monomers surprisingly largely independent of the Catalyst concentration. This means that the activity of the catalyst with increasing dilution increases sharply. By diluting the nickel tetracarbonyl namely, the concentration of carbon monoxide is also reduced at the same time, because the theoretically expected amount of carbon monoxide in the amount of nickel tetracarbonyl is proportional.

It is particularly advantageous to combine the two possibilities mentioned, to keep the carbon monoxide concentration low by removing the nickel tetracarbonyl applies in low concentration and also takes measures to reduce carbon monoxide to be removed from the exposure mixture.

To prepare the catalyst, one can, for example, proceed as follows: that one nickel tetracarbonyl, a polyene and optionally a solvent in a pressure vessel is heated to the reaction temperature and the mixture is closed over time Relaxed time.

It is also possible through the action mixture a To conduct inert gas, e.g. B. nitrogen or argon, and optionally from the gas stream to separate the entrained, liquid components of the action mixture and returned. The catalyst mixture that is created in this way is used then in the usual way for the oligomerization. So you work at temperatures which are expediently between 50 and 150 ° C. At lower temperatures, the reaction rate is only slightly, by-products appear to an increasing extent at higher temperatures. You can work under atmospheric pressure or use increased pressure, for example the pressure, which results from the vapor pressure of the reactants at the respective Temperature results. If you want to make mixed oligomers of 1,3-dienes, that's it expedient, the concentration of the olefin high and that of the 1,3-diene too low keep. In this way, the formation of homooligomers of 1,3-dienes is suppressed.

It is particularly advantageous to use the production of the catalyst to connect the actual oligomerization by adding nickel tetracarbonyl to the reaction mixture feeds and the catalyst produces from this and the 1,3-diene to be converted. For example, nickel tetracarbonyl is continuously brought into a pressure vessel with a stirrer and the 1,3-diene and optionally relaxes the reaction mixture from time to time at times or continuously removes exhaust gas. The escaping gases are then separated by cooling the 1,3-diene and other easily condensable components from while the carbon monoxide as such escapes.

If the method is carried out continuously, this leads to it the reaction is carried out in a stirred tank cascade. This is the first boiler only a part, for example up to 500 / o of the total amount, of the monomers fed and the reaction by feeding the remaining starting materials into the following stirred vessels completed. It is expedient to take from the first stirred vessel and if necessary also one or more of the following stirred vessels carbon monoxide to the one described Way. In many cases it is expedient to implement the last fractions of the starting materials as well no more monomers to be added to the last stirred vessel. Working up the reaction mixtures takes place here, as in all other embodiments of the method, expediently Distillation.

The parts mentioned in the following examples are parts by weight. They relate to parts of space like grams to cubic centimeters.

Example 1 In a pressure vessel with exclusion of oxygen and moisture 500 parts of butadiene, 50 parts by volume of benzene and 0.25 parts of nickel tetracarbonyl heated to 100 ° C. 10000 parts by volume of exhaust gas are withdrawn from the pressure vessel every hour replaces the 1,3-diene thus discharged with the corresponding amount of fresh Butadiene. After 8 hours, the removal of exhaust gas and the supply of butadiene interrupted. The mixture is kept at the same temperature for a further 8 hours it then works up through fractional distillation.

81% of the butadiene used has been converted. You get Cyclooctadiene (1.5) from Bp. 760 150 to 151 "C in a yield of 23% and cyclododecatriene- (l, 5.9) in a yield of 690 / o, based on converted butadiene.

Example 2 The mixture is heated in a pressure vessel with the exclusion of oxygen and moisture 200 parts of butadiene and 1 part of nickel tetracarbonyl to 105 "C. Man removes a total of 10,000 parts by volume of exhaust gas from the reaction vessel within 5 hours and then runs hourly under a constant ethylene pressure of 125 atm 60 parts of butadiene. The reaction time is 5 hours.

The gas chromatographic analysis of the reaction mixture shows that 70 parts of cyclooctadiene (1.5), 30 parts of cyclododecatriene (l, 5.9), 19.8 parts Decatriene (1,5,9), 6.5 parts 1,2-divinylcyclohexane, 61.2 parts cyclooctadiene (1.5) and 87 parts of a mixture of fifteen other hydrocarbons known to date unknown structure were formed. The reaction products can be through careful Separate fractionation. The previously unknown Cl0 hydrocarbons are thereby used Decatriene- (1,5,9) from bp 50 83.5 to 84 "C and the refractive index n2D = 1.4505, 1,2-divinylcyclohexane from bp so 85.5 to 86.5 "C and the refractive index n2D = = 1.4708 as well as cyclodecadiene- (l, 5) from bp 50 100 to 101 "C and the refractive index n2D = 1.4945.

Example 3 In a stirred tank with a volume of 235 parts by volume, 100 "C hourly 0.019 part of nickel tetracarbonyl, dissolved in 2 parts of cyclooctadiene (1.5), introduced. At the same time, liquid butadiene is pumped in as it is consumed, so that a pressure of 2.4 atmospheres is maintained. The average butadiene intake is 18.3 parts per hour.

At the same time, 2.3% of the butadiene fed in becomes gaseous withdrawn to discharge inert gas and carbon monoxide. The reaction mixture is continuously discharged via an overflow. In a downstream dwelling the butadiene dissolved in the reaction mixture has its amount equal to the saturation pressure corresponds to the reaction temperature, opportunity for post-reaction.

In the course of 6 hours, 122 parts of the discharge are obtained still contains 0.7 percent by weight of unreacted butadiene. The analysis of the discharge shows that the following butadiene oligomers were formed: 7.8 01o l-vinylcyclohexene (3), 380 / o cyclooctadiene- (1.5), 46.1 ° / o cyclododecatriene- (1,5.9), 5.1% of a mixture of Cl6 hydrocarbons and 2.2 0 / o higher oligomers, which are used as distillation residue remain. The yield data are based on converted butadiene.

If you work under the same conditions, however, only leads every hour 0.010 part of nickel tetracarbonyl in 2 parts of cyclooctadiene (1.5) is obtained 119 parts of reaction mixture in 6 hours. One obtains, based on converted butadiene, 80 / o l-vinylcyclohexene (3), 340 / o cyclooctadiene (1,5), 500 / o cyclododecatriene (1,5,9), 4.8% Cl6 hydrocarbons and 2% residue.

Example 4 A pressure vessel provided with a stirrer and evaporative cooling is under an inert gas atmosphere with a Solution of 1.3 parts of nickel tetracarbonyl charged in 400 parts of benzene and 1600 parts of liquid butadiene. One heats up under reflux to 105 to 1100 C, while at the same time within 2 hours 42 000 room parts of exhaust gas are discharged from the system. The system pressure drops within this time from originally 12 atm to 2 atm. The reaction product, a orange-colored solution, still contains 6 percent by weight of dissolved butadiene. According to gas chromatography Analysis was 820 / o of the converted butadiene to cyclododecatriene- (1,5,9), 9% oligomerized to cyclooctadiene (1.5) and 7.5 ° / 0 to l-vinylcyclohexene43).

For the preparation of the catalyst protection is within the scope of the present Invention not claimed.

Claims (1)

Process for the production of predominantly alicyclic Oligomers of 1,3-dienes from the 1,3-dienes and optionally from aliphatic ones Monoolefins in the presence of a catalyst obtainable from nickel tetracarbonyl, d a - characterized in that a catalyst is used which consists of nickel tetracarbonyl and a polyene was prepared, during the mutual action of the catalyst components kept the concentration of carbon monoxide low. Considered publications: Angewandte Chemie, Vol. 73, 1961, P.755/756.