JPH0148887B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for oligomerizing α-olefins. Conventionally, a method has been known in which an oligomer is obtained by reacting an α-olefin using a metal halide such as aluminum trichloride or ethylaluminum dichloride as a catalyst. However, when oligomerization is carried out using these metal halides as catalysts, products with considerably high molecular weight,
For example, a large amount of pentamer or higher products of the raw material α-olefin are produced as by-products. On the other hand, α-olefin oligomers, that is, higher olefins, are useful as raw materials for detergents, plasticizers, and the like. As a result of research into a method for oligomerizing α-olefin, the present inventors found that oligomers can be formed by reacting α-olefin with a complex of halogenated metals and a halogenated aliphatic carboxylic acid, which is a protonic acid. The present invention was completed by discovering that it can be produced in good yield. That is, the present invention relates to an aluminum trihalide represented by the general formula AlX ₃ (X is a halogen atom) and/or an organoaluminum dihalide represented by the general formula AlRX ₂ (R is an alkyl group, X is a halogen atom), and a halogenated The gist of this invention is a method for oligomerizing α-olefin, which is characterized by reacting α-olefin in a nonpolar solvent in the presence of a catalyst consisting of an aliphatic carboxylic acid. Examples of the aluminum trihalide used in the present invention include aluminum trichloride and aluminum tribromide. Further, as the organoaluminum dihalide, for example,
Examples include methylaluminum dichloride, ethylaluminum dichloride, ethylaluminum dibromide, ethylaluminum diiodide, propylaluminum dichloride, butylaluminum dibromide, and cyclohexylaluminum dichloride, with ethylaluminum dichloride being particularly preferred. Note that the aluminum trihalide and the organoaluminum dihalide may be used in an appropriate mixture. Next, in the present invention, a halogenated aliphatic carboxylic acid is further added as a catalyst. Examples of the halogenated aliphatic carboxylic acid include chloroacetic acid,
Examples include halogenated acetic acids such as bromoacetic acid, halogenated propionic acids such as chloropropionic acid, and particularly preferred are polyhalogenated aliphatic carboxylic acids such as dichloroacetic acid and trichloroacetic acid. In the method of the present invention, the halogenated aliphatic carboxylic acid, which is the latter catalyst component, is
It is added in an amount of 0.05 to 10 mol, preferably 0.1 mol to 2 mol. Further, it is preferable to carry out a ripening operation after mixing both components of the catalyst, and the ripening temperature is suitably 50°C to 70°C, and the ripening time is suitably 1 hour to 5 hours. The oligomerization method of the present invention uses non-polar solvents. Examples of the nonpolar solvent include saturated aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons such as cyclohexane, and halogenated hydrocarbons such as carbon tetrachloride. The reaction temperature is 0°C to 80°C, more preferably
The temperature is between 50°C and 80°C. Further, the reaction pressure does not need to be particularly high, as long as it is a pressure necessary to maintain the reaction phase in a liquid phase. α- which can be oligomerized by the catalyst system of the present invention
Although the number of carbon atoms in the olefin is not limited, α-olefins having 4 or more carbon atoms, such as 1-butene, 1-hexene, and 1-octene, are preferred. however,
If the number of carbon atoms exceeds 15, the reactivity decreases, which is not preferable. Further, after the reaction, an oligomer can be obtained by deactivating the catalyst and separating unreacted α-olefin by an appropriate operation such as distillation. The oligomers obtained are mainly dimers to tetramers, but the composition ratio of the oligomers produced can be changed by appropriately selecting the type of catalyst, quantitative ratio, monomer concentration, catalyst concentration, and reaction temperature. Next, the present invention will be explained in detail with reference to Examples. Example 1 30 mmol of ethylaluminum dichloride, 30 mmol of trichloroacetic acid and 1 mole of hexene-1 were added to 1000 ml of n-hexane, and the mixture was reacted for 24 hours at a reaction temperature of 70° C. under a stream of dry nitrogen.
After the reaction was completed, the reaction product was analyzed by high performance liquid chromatography and gas chromatography. The results are shown in Table 1. Examples 2 to 3 In Example 2, the reaction was carried out in the same manner as in Example 1 except that dichloroacetic acid was used instead of trichloroacetic acid. In Example 3, the reaction was carried out in the same manner as in Example 1 except that aluminum trichloride was used instead of ethylaluminum dichloride. Example 4 A reaction was carried out in the same manner as in Example 1 except that octene-1 was used instead of hexene-1 as the α-olefin. Comparative Examples 1 and 2 In Comparative Example 1, only ethylaluminum dichloride was used as a catalyst, and in Comparative Example 2, only aluminum trichloride was used as a catalyst, and the reaction was carried out in the same manner as in Example 1. Comparative Example 3 A reaction was carried out in the same manner as in Example 1 except that 1,2-dichloroethane was used as the solvent instead of n-hexane. Comparative Example 4 The reaction was carried out in the same manner as in Example 1, except that acetic acid was used instead of trichloroacetic acid.
Hexene-1 hardly reacted. The results are shown in the following table, and it can be seen that according to the method of the present invention, oligomers in the order of dimers and tetramers can be synthesized in high yield under mild conditions. 【table】

Claims (1)

[Claims] 1. Aluminum trihalide represented by the general formula AlX ₃ (wherein, X is a halogen atom) and/or organoaluminum represented by the general formula AlRX ₂ (wherein, R is an alkyl group and X is a halogen atom) A method for oligomerizing α-olefin, which comprises reacting α-olefin in a nonpolar solvent in the presence of a catalyst consisting of a complex of a dihalide and a halogenated aliphatic carboxylic acid. 2. The method for oligomerizing α-olefin according to claim 1, wherein the organoaluminum dihalide is ethylaluminum dichloride. 3. The α-olefin oligomerization method according to claim 1 or 2, wherein the halogenated aliphatic carboxylic acid is halogenated acetic acid. 4. The method for oligomerizing α-olefin according to any one of claims 1 to 3, wherein the nonpolar solvent is a saturated aliphatic hydrocarbon. 5. The method for oligomerizing α-olefin according to any one of claims 1 to 4, wherein the α-olefin has 4 or more carbon atoms.