JPH0674216B2 - Internal olefin manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an internal olefin, and more particularly to a method for producing a more stable internal olefin by isomerizing an olefin in the presence of a specific catalyst. Is.

<Problems to be Solved by Prior Art and Invention> Various methods for isomerizing an olefin to a more stable internal olefin are known. However, generally, in the known methods, there are many undesired factors such as decomposition of olefin, giving unnecessary olefin polymer, and randomization, which are economically disadvantageous. .

As a catalyst for such an isomerization reaction, a liquid base such as a mixture of an alkali metal hydroxide and an aprotic organic solvent, an alkali metal amide and an amine, or an organic alkali metal and an aliphatic amine is known. However,
In the method using such a liquid base reagent, the catalytic activity is not sufficient and a large amount of expensive reagent is required, and it is difficult to separate and collect the reagent from the reaction mass, and a complicated separation is required. There is a problem that not only a recovery process is required but also a large amount of energy is consumed.

Further, as a solid isomerization catalyst, a catalyst in which an alkali metal is dispersed in a carrier having a large surface area, such as activated carbon, silica gel, or alumina, is known (J. Am. Chem. Soc.
82 387 (1960)).

However, in such a solid catalyst, the alkali metal itself is simply finely dispersed on the carrier, and when contacted with air, it is ignited and deactivated, so that there is a big problem in terms of operability and safety. The isomerization ability was also unsatisfactory.

The present inventors have already used alumina, an alkali metal hydroxide, a novel catalyst using an alkali metal as a raw material, and a hydrous alumina and an alkali metal as a raw material, as an efficient catalyst that does not have such problems of an isomerization catalyst. In addition to finding new catalysts, they have found that these solid base catalysts are safer without danger of ignition in the air and are excellent catalysts for isomerizing olefins into internal olefins (Japanese Patent Publication No. 57-21378, Japanese Examined Sho 55-29055
No. 54-41562, Sho-55-29056, Sho-55-2
9058 publication).

The present inventors have further studied the production of internal olefins using such a solid base catalyst in order to find a more industrially excellent method, and as a result, heat the hydrous alumina and the alkali metal that are the raw materials of the catalyst. The temperature is particularly important, and it was found that the catalyst activity was remarkably improved if prepared under a specific temperature, and the isomerization proceeded efficiently with a small amount of catalyst, and the present invention was completed by further various studies.

<Means for Solving the Problem> That is, in the present invention, in isomerizing the double bond of the olefin to produce a more stable internal olefin, the equivalent amount is exceeded with respect to the water-containing alumina and the water molar amount of the alumina. To provide an industrially excellent method for producing an internal olefin, which is characterized by using a solid base catalyst obtained by heating an amount of an alkali metal in an inert gas atmosphere at a temperature of 180 to 350 ° C. is there.

As the hydrous alumina which is a raw material of the solid base catalyst in the present invention, various forms of hydrous alumina other than α-alumina are used.

Alumina is usually produced by calcining aluminum hydroxide, but it is known that various metastable structures are taken depending on the calcining temperature and calcining time, and the amount of water contained in it also varies, so that there are various forms of alumina. There is. In the present invention, such alumina is mainly used. In particular, high surface area alumina such as γ-, χ-, and ρ-type is preferably used. Further, a hydrated substance containing an alumina, for example, a hydrated substance such as kaolin or alumina silicate can be used, but the above-mentioned alumina is particularly preferable. Further, it is said that the alumina eventually turns into α-alumina as the firing temperature rises, and the heating loss of the alumina disappears. Although it is not so easy to measure the amount of water contained in alumina, it can be represented by the weight loss on heating from the initial various forms of alumina to the conversion to α-alumina. The water content of hydrated alumina is usually 1.3 to 10% by weight, preferably 2 to 7% by weight.
Is the range.

Examples of the alkali metal which is another raw material of the catalyst used in the present invention include sodium, potassium and rubidium of the 1st group of the periodic table. Two or more kinds of these alkali metals may be used, or an alloy thereof, for example, an alloy of sodium and potassium may be used.

The amount of the alkali metal used is required to be more than the amount equivalent to the molar amount of water contained in the hydrated alumina, and preferably 1.01 to 2 times the amount equivalent to the amount of water.

When the alkali metal is allowed to act on the hydrated alumina, a predetermined amount of the alkali metal may be added at once, or after addition of the equivalent amount of the moisture of the hydrated alumina and sufficient reaction, the remaining alkali metal may be added. good. In the latter case, the alkali metal added first and the alkali metal added later may be different.

The catalyst used in the present invention is a catalyst prepared by allowing the above-mentioned hydrous alumina and alkali metal to act at a specific temperature in an inert gas atmosphere, and the inert gas is nitrogen or helium. , Argon, etc. are exemplified.

The preparation temperature of the catalyst used in the present invention, that is, the temperature at which the hydrous alumina and the alkali metal are allowed to act on each other is extremely important, and the catalyst activity is significantly affected. The catalyst preparation temperature is 180 to 350 ℃, more preferably 200 to 330
℃. If the catalyst is prepared at such a temperature, a catalyst having a remarkably high activity which has never been obtained can be obtained, and the target reaction can be efficiently completed with a small amount of the catalyst.

The heating time varies depending on the selected temperature conditions and the like, but 15 minutes to 10 hours is usually sufficient.

Thus, as compared with the known solid base catalyst, a safer and highly active catalyst can be obtained without danger of ignition.

Although the present invention uses such a solid base catalyst to isomerize an olefin into a more stable internal olefin,
Examples of the raw material olefin include 1-butene and 1
-Pentene, 1-hexene, 1-heptene, 1-nonene, 1-decene, 2-methyl-1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene Chain compounds such as 2-methyl-1-pentene and 2,3-dimethyl-1-butene, allylbenzene,
Aromatic compounds such as allyltoluene, cross-linked ring compounds such as 2-isopropenylnorbornane, 5-isopropenyl-2-norbornene, 6-methyl-5-vinylnorbornene (however, 5-vinyl-2-norbornene is excluded),
Cyclic compounds such as methylenecyclopentane and methylenecyclohexane, 1,4-pentadiene, 1,5-hexadiene,
2,5-dimethyl-1,4-hexadiene, 2,5-dimethyl-
Terminal olefin compounds such as non-conjugated olefins such as 1,5-hexadiene, 4-methyl-2-pentene, 5- (2
Examples thereof include compounds having a double bond other than the terminal such as -propenyl) -2-norbornene and capable of isomerizing at a more stable position.

The amount of the solid base catalyst used in producing the internal olefin is usually 1/3000 to 1/50 weight, preferably 1/2000 to 1/100 weight, relative to the raw material. Regarding the isomerization temperature, the reaction proceeds sufficiently even at room temperature, so that it is not particularly necessary to heat it, but it may be heated depending on the purpose. Usually -30 to 120 ° C, preferably -10 to 100
It is carried out in the temperature range of ° C.

If necessary, the reaction can be carried out by diluting it with an inert medium, for example, hydrocarbons such as pentane, hexane, heptane, dodecane, etc., but no medium is sufficient. The method of the present invention can be carried out by a batch method or a continuous method, and it is also effective to pretreat the raw material with a desiccant such as alumina in advance for isomerization. In order to carry out isomerization more safely and surely, it may be carried out under an inert gas atmosphere.

The isomerization reaction product is analyzed by a known method such as gas chromatography and separated from the catalyst by filtration or the like.

<Effect of the Invention> Thus, the internal olefin isomerized to a more stable position, which is the object of the present invention, can be obtained, but according to the method of the present invention, the olefin isomerization is extremely efficiently performed even with a significantly small amount of catalyst as compared with the known method. The reaction can be completed, and an internal olefin can be obtained in high yield without accompanying byproducts such as a polymer. In addition, since the reaction can be safely proceeded without danger of ignition and the like, it is extremely useful as a method for industrially producing an internal olefin.

<Example> The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples.

Reference Example 1 30.0 g of γ-alumina containing 2.2% by weight of water was placed in a 100 ml flask and stirred at 300 ° C. under nitrogen gas flow.
Heated to. 1.2 g of metallic sodium was introduced, and the mixture was stirred at the same temperature for 1 hour and allowed to cool. 30.9 g of an off-blue catalyst was obtained.

Reference Example 2 30.0 g of γ-alumina containing 2.0% by weight of water was placed in a 100 ml flask and stirred at 260 ° C. under a nitrogen gas flow.
Heated to. 0.75 g of metallic sodium and 0.4 of metallic potassium
After adding 5 g and stirring for 1 hour, the mixture was allowed to cool. Gray-blue catalyst 31.0
got g.

Reference Example 3 30.0 g of γ-alumina containing 2.2% by weight of water was placed in a 100 ml flask and stirred at 210 ° C. under nitrogen gas flow.
Heated to. 1.2 g of metallic sodium was introduced, and the mixture was stirred at the same temperature for 1 hour and allowed to cool. 30.8 g of an off-blue catalyst was obtained.

Reference Example 4 30.0 g of γ-alumina containing 2.2% by weight of water was placed in a 100 ml flask and stirred at 400 ° C. under nitrogen gas flow.
Heated to. 1.2 g of metallic sodium was introduced, and the mixture was stirred at the same temperature for 1 hour and allowed to cool. 30.9 g of an off-blue catalyst was obtained.

Example 1 In a 100 ml flask under a nitrogen atmosphere, 0.25 g of the solid base prepared in Reference Example 1 and 4-methyl-1-pentene (composition: 4-methyl-1-pentene 98.9%, 4-methyl-2-pentene 1.
1%) 22.2 g was added and the mixture was stirred at 15 to 20 ° C. for 16 hours, and then the reaction solution was analyzed. As a result, 4-methyl-1-pentene 0.4% and 4%
-Methyl-2-pentene 10.8% and 2-methyl-2-pentene 88.8%.

Example 2 To a 100 ml flask, under a nitrogen atmosphere, 0.20 g of the solid base prepared in Reference Example 2 and 28.0 g of 4-methyl-1-pentene (composition: the same as in Example 1) were added and stirred at 15 to 20 ° C for 16 hours. The post-reaction liquid was analyzed and found to be 4-methyl-1-pentene.
4%, 4-methyl-2-pentene 9.0%, 2-methyl-2
-Pentene 90.6%.

Example 3 To a 100 ml flask, under a nitrogen atmosphere, 0.23 g of the solid base prepared in Reference Example 3 and 20.7 g of 4-methyl-1-pentene (composition: same as in Example 1) were added and stirred at 15 to 20 ° C. for 16 hours. The post-reaction liquid was analyzed and found to be 4-methyl-1-pentene.
6%, 4-methyl-2-pentene 37.8%, 2-methyl-
The content of 2-pentene was 61.6%.

Comparative Example 1 0.25 g of the solid base prepared in Reference Example 4 and 22.2 g of 4-methyl-1-pentene (composition: the same as in Example 1) were added to a 100 ml flask under a nitrogen atmosphere and stirred at 15 to 20 ° C. for 16 hours. When the post-reaction liquid was analyzed, 4-methyl-1-pentene was 1.
5%, 4-methyl-2-pentene 53.2%, 2-methyl-
2-pentene was 45.3%.

Example 4 0.25 g of the solid base prepared in Reference Example 1 and 2,3-dimethyl-1-butene (composition: 2,3-
Dimethyl-1-butene 99.4% and 2,3-dimethyl-2-butene 0.6%) 45.0 g were added, and the mixture was stirred at 15 to 20 ° C. for 24 hours.
After the reaction, the catalyst was separated by filtration to obtain 43.3 g of a reaction liquid. This was analyzed by gas chromatography to find that 2,3-dimethyl-1-butene 8.0%, 2,3-dimethyl-2
-Butene was 92.0%.

Comparative Example 2 Under a nitrogen atmosphere, 0.24 g of the solid base prepared in Reference Example 4 and 43.2 g of 2,3-dimethyl-1-butene used in Example 4 were added to a 100 ml flask and stirred at 15 to 20 ° C. for 24 hours. . After the reaction, the catalyst was separated by filtration to obtain 41.5 g of a reaction solution. When this product was analyzed by gas chromatography, it was found that 2,3-dimethyl-1-butene was 34.8% and 2,3-dimethyl-2-butene was 65.2%.

Claims (1)

[Claims] 1. When isomerizing an olefin to produce a stable internal olefin, hydrous alumina and an amount of alkali metal in an amount exceeding the equivalent amount to the molar amount of water of the alumina are contained in an inert gas atmosphere at 180 to 350. A method for producing an internal olefin, which comprises using a solid base catalyst heated at a temperature of ℃.