DE1135436B - Process for the production of tri- and hexasubstituted benzenes from substituted acetylene hydrocarbons by means of catalysts containing titanium and aluminum - Google Patents

Description

Process for the preparation of tri- and hexasubstituted benzenes from substituted acetylene hydrocarbons by means of titanium and aluminum containing Catalysts It is known that tri- or hexasubstituted benzenes by catalytic trimerization of mono- or disubstituted acetylene hydrocarbons can produce. If one uses in this reaction: V-alkynes, trisubstituted ones are obtained Benzenes, while the trimerization of disubstituted acetylenes to hexasubstituted Benzenes leads. The catalysts for this known process are organometallic Compounds and metal carbonyls, optionally together with halides of the transition metals (Belgian patent 567744, British patent 802510; Abstracts of Papers of the 134.

Meeting of the American Chemical Society, September 7-12: 1958, P. 59P, Section 98; Journal of the American Chemical Society, 80, [1958], p. 2913) It has now been found that tri- or hexasubstituted benzenes by catalytic Trimerizing mono- or disubstituted acetylenic hydrocarbons by means of Catalysts containing titanium and aluminum, expediently in the presence of a solvent and in an inert gas atmosphere, advantageously obtained when one of a titanium (IV) acid ester, Titanium halide, titanium ester halide or organotitanium halide, from aluminum metal and optionally an aluminum halide obtainable per se known catalyst used.

With the new procedure, the relatively difficult to access, spontaneously flammable and partly poisonous metal compounds, the ones mentioned above Procedures used are accessible, cheap and easy to use Substances such as aluminum and aluminum halides replaced.

Such catalysts are already used for the polymerization of ethylene been used for high molecular weight polyethylenes (German patent specification 874215, French patent 1161787). Yet it is not from these publications it can be seen that acetylene hydrocarbons substituted with these catalysts are polymerized to low molecular weight polymers, in particular to give alkylbenzenes can.

Suitable starting materials are one or two times by aliphatic, cycloaliphatic, araliphatic and / or aromatic substituted acetylenes. Examples include: propyne, butyne- (l), pentyne- (l), hexyne- (l), Octyne- (l), vinylacetylene, phenylacetylene, cyclohexyl acetylene, benzylacetylene, butyne- (2), Hexyne- (3), methylethyl-acetylene and tolane.

Suitable titanium compounds for the reaction are titanium (IV) acid esters, especially those that are derived from lower alcohols, such as titanium tetramethylate, Titanium tetraethylate and titanium tetrapropylate, also titanium tri- and tetrahalides, such as titanium trichloride, titanium tribromide, titanium tetrabromide and especially titanium tetrachloride, and titanium ester halides such as diethoxytitanium (IV) dichloride. Also organotitanium halides, such as bis-cyclopentadienyl titanium (IV) dichloride and dialkyl titanium (IV) dichloride usable.

The aluminum is expediently used in a form that is not too compact. Aluminum dust, aluminum powder and aluminum grit with grain sizes between 0.01 and 2 mm work well for the reaction.

Of the aluminum halides that can also be used Aluminum bromide and especially aluminum chloride are preferred. The quantities in which the substances mentioned in the formation of the catalyst can be used within further limits fluctuate. So you get z. B. at proportions titanium compound : Aluminum: aluminum halide (in moles or gram atoms) such as 1: 300: 100 and 1:10:10 good yields. The catalyst only needs a small amount, based on on the alkyne used to be used. At a catalyst concentration of 0.30 / »the reaction proceeds at a satisfactory rate.

Suitable solvents for the process are benzene, toluene, xylene, Ethylbenzene, cumene, chlorobenzene, heptane, cyclohexane and isooctane. It is recommended, Use anhydrous and pure solvents, with the aromatic hydrocarbons to be favoured. Solvent mixtures are also well suited for the implementation, for example those that are predominantly chlorobenzene, heptane or cyclohexane and in contain a small amount of benzene or toluene.

The process can be carried out within a wide temperature range, namely between - 50 and + 150 ° C. The preferred reaction temperature is between -20 and + 100 ° C, in particular between 30 and 80 "C.

The reaction in the process is usually carried out under atmospheric pressure before, but a procedure under reduced or increased pressure is also possible. Especially when using low-boiling starting materials and at elevated reaction temperatures Elevated pressures, for example up to 10 atm, are sometimes required.

To carry out the process, it is advantageous to first "develop" the catalyst by adding the titanium compound, aluminum and optionally the Aluminum halide, expediently in the solvent provided for the reaction and under the atmosphere of an inert gas, such as nitrogen or argon, for some time, for example up to 10 hours, thoroughly mixed. Such mixing is achieved one z. B. in a ball mill. The optimal duration of mixing depends, among other things depends on the components used and can easily be determined by experiment. It is noteworthy that the activity of the catalyst in some cases by too long mixing is reduced again. You can see the "evolution" of the catalyst make advantageous also in such a way that only one or two of the catalyst components, z. B. aluminum and or the aluminum halide, with the intended solvent mixed and the dispersion thus obtained with a solution or dispersion of the Titanium compound united. Finally, you can also use the catalyst components Submit in a solvent and immediately with thorough mixing, z. B. by a powerful stirrer to add the alkyne. The "development" of the catalyst however, before the alkyne is added, it is expedient in many cases.

The conversion of the alkyne takes place with strong heat development. The desired reaction temperature is achieved by adding the starting material accordingly and, if necessary, adhered to by external cooling. To complete the implementation the reaction temperature is maintained after the feed of the starting material has ended appropriately upright for some time. Before working on the approach, it is advantageous to destroy the catalyst. This is done, for example, by carefully adding a small amount of water or an alcohol or by adding a larger amount Amount of acetone, which may result in small amounts of high molecular weight products, that arise during the implementation of or-Afkinen, are separated.

The parts mentioned in the following examples are parts by weight.

Example 1 In a vibrating mill, 15 parts of aluminum and 15 parts Parts of aluminum chloride ground in 180 parts of benzene for 24 hours. From the received 18 parts to 90 parts of toluene and 1.14 parts of titanium tetrachloride are added to the dispersion included, given. Now 18 parts of n-octyne- (l) are carefully added, whereby one the temperature is kept at 50 ° C. by cooling. The mixture is then left for a further 3 hours stir at room temperature and then decompose the catalyst by adding 10 Share methanol. The reaction solution is with 100 /, the sulfuric acid and water washed, the organic phase dried over calcium chloride and distilled. 10 parts of a fraction are obtained which boil and expire at 120 to 130 "C / 10-4 Torr an approximately equimolecular mixture of 1,3,5- and 1,2,4-tri-n-hexylbenzene. The refractive index is n = 1.4830. 4 parts remain as distillation residue of a dark brown viscous oil.

Example 2 From 19 parts of the aluminum-aluminum chloride suspension described in Example 1 and 1.14 parts of titanium tetrachloride in 70 parts of benzene is the catalyst suspension manufactured. A solution of 30 parts of tolane in 50 parts is added to this mixture Benzene added, the reaction temperature being kept at 60 ° C. by cooling The reaction is completed and the mixture is stirred at room temperature for a further 2 hours. the The reaction solution is then poured into 400 parts of methanolic hydrochloric acid. Be there 8 parts of hexaphenylbenzene with a melting point of 423 to 427 "C are precipitated.

Example 3 The catalyst is made from 19 parts of aluminum-aluminum chloride suspension (Example 1), 1.14 parts of titanium tetrachloride and 90 parts of benzene.

110 are slowly added to this mixture with simultaneous cooling Parts of phenylacetylene given; the reaction temperature is kept at 50.degree.

The mixture is stirred for a further 24 hours at room temperature and then poured into 500 parts of acetone. This separates 20 parts of crystallized 1.3, 5-triphenylbenzene with a melting point of 172 "C. The acetone solution is washed with water, the organic phase is dried over calcium chloride and then the benzene distilled off.

By crystallization from alcohol can be made from the distillation residue 50 parts of a mixture of 1,3,5- and 1,2,4-triphenylbenzene with a melting point of 106 "C to win.

Example 4 The catalyst used in Example 3 is used and converts 20 parts of hexyne- (3) at 60 "C.

The reaction mixture is stirred at 60 ° C. for a further 5 hours, then washed with dilute sulfuric acid and water and washed over calcium chloride dried. After the benzene has been distilled off, 16 parts of hexaethylbenzene remain as the distillation residue of melting point 128 "C.

Example 5 1.14 parts of titanium tetrachloride and 2 parts of aluminum powder are ground in 90 parts of benzene for 3 hours. The resulting suspension is in transferred to a stirred vessel and then over the course of an hour with 45 parts of hexyne- (3) offset. The temperature is kept at 50 ° C. by cooling. The mixture is left for a further 2 hours post-react, decomposes the catalyst with methanol and washes the reaction solution one after the other with dilute sulfuric acid and water.

The dried solution is freed from benzene in vacuo. As a residue 40 parts of hexaethylbenzene with a melting point of 128 ° C. remain.

Claims (1)

PATENT CLAIM: Process for the production of tri- or hexasubstituted Benzenes by trimerizing mono- or disubstituted acetylene hydrocarbons by means of catalysts containing titanium and aluminum, expediently in the presence a solvent and in an inert gas atmosphere, characterized in that one of a titanium (IV) acid ester, titanium halide, titanium ester halide or Organotitanium halide and from aluminum metal and optionally an aluminum halide available, known catalyst used. Documents considered: German Patent No. 874 215; British Patent No. 802 510; French patent specification No. 1161 787.