JPH0684318B2 - Internal olefin production method - Google Patents

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. It is a thing.

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

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.
82 887 (1960)). However, in such a solid catalyst, the alkali metal itself is finely dispersed on the carrier, and when it comes into contact 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 made alumina, an alkali metal hydroxide, a new catalyst made from an alkali metal and an alkali metal act on a hydrous alumina as an efficient catalyst which does not have such problems of the isomerization catalyst. While finding a catalyst, this one does not cause danger such as ignition in the air,
It has been found that it is safer and industrially superior as an isomerization catalyst (Japanese Patent Publication No. 50-3274 and Japanese Patent Publication No. 57-21378). However, it is not always satisfactory in terms of using an alkali metal as a raw material and in terms of isomerization ability.

A method is also known in which a solid catalyst having an alkali metal hydride supported on a carrier is used in combination with ammonia or hydrazine (JP-A-53-121753 and JP-A-59-134736). However, in this method, since ammonia, hydrazine and the like are used as an auxiliary agent, the auxiliary agent must be separated and recovered from the reaction mass, and a device for separation and recovery is required and the operation is complicated. Have a point.

In order to solve the problems of the above-mentioned known methods, the present inventors have made extensive studies, and a solid base obtained by heating hydrous alumina and an alkali metal hydride at a specific temperature is heated,
It has been found that even by itself, it exhibits a remarkably high isomerization ability, and further various studies were conducted to complete the present invention.

<Means for Solving Problems> That is, in the present invention, in producing a more stable internal olefin by isomerizing the double bond of the olefin, the equivalent amount is exceeded with respect to the water-containing alumina and the molar amount of water of the alumina. A method for producing an industrially excellent internal olefin characterized by using a solid base obtained by heating a large amount of an alkali metal hydride in an inert gas atmosphere in a temperature range of 200 to 500 ° C. It is provided.

As the hydrous alumina which is a raw material of the solid base 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 hydrous alumina such as γ-, χ-, and ρ-type is preferably used.

Alumina eventually becomes α- as the firing temperature increases.
It is said that it will be changed to alumina and the heating loss of alumina will disappear. Although it is not so easy to measure the amount of water contained in alumina, α-
It can be represented by the weight loss on heating until it changes to alumina. The water content of the hydrous alumina used in the present invention is usually 1.2 to 10% by weight, preferably 2 to 7% by weight.

Examples of the alkali metal hydride used in the present invention include hydrides such as sodium, potassium and lithium of Group 1 of the periodic table. It does not matter if two or more kinds of these alkali metal hydrides are used.

The amount of such an alkali metal hydride used should be an amount exceeding the equivalent amount to the molar amount of water of the hydrated alumina, and preferably 1.01 to 2 times equivalent amount to the moisture.

When the alkali metal hydride is allowed to act on the hydrated alumina, a predetermined amount of the alkali metal hydride may be added at a time, or the moisture of the hydrated alumina may be added in an equivalent amount to allow sufficient reaction, and then the remaining alkali metal hydrogen Compounds may be added. In the latter case, it does not matter if the alkali metal hydride added first is different from the alkali metal hydride added later. These alkali metal hydrides are generally readily available as a dispersion of an inert medium such as powder or mineral oil, and when a dispersion of an inert medium is used, it may be used after separating the medium, or together with the medium. After use, it can be separated by distillation or the like.

Alternatively, a method in which an alkali metal is supported on hydrated alumina and hydrogen is allowed to act on this to effect hydrogenation can be used.

The catalyst used in the present invention is prepared by heating the above-mentioned hydrous alumina and alkali metal hydride in an inert gas atmosphere at a specific temperature, and nitrogen is used as the inert gas. 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 hydride are heated, is extremely important and significantly affects the catalytic activity. The catalyst preparation temperature is 200 to 500 ° C, more preferably 250 to 450 ° C. If the catalyst is prepared at such a temperature, a catalyst having a remarkably high activity that 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 condition, but 15 minutes to 10 hours is usually sufficient.

Thus, the solid base used in the present invention is produced. It is considered that the hydrous alumina and the alkali metal hydride act on each other to form a new active species in the solid base, which is remarkably high in activity as compared with known catalysts, and the activity of ammonia, hydrazine, etc. The desired reaction can be completed without using any agent and even in a small amount.

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, 2-isopropenyl norbornane, 5-isopropenyl-2-norbornene, 5-vinyl-2-norbornene, 6-methyl-5-
Bridged ring compounds such as vinyl norbornene Cyclic compounds such as methylenecyclopentane and methylenecyclohexane, 1,4
-Pentadiene, 1,5-hexadiene, 2,5-dimethyl-
Terminal olefin compounds such as non-conjugated olefins such as 1,4-hexadiene and 2,5-dimethyl-1,5-hexadiene,
4-methyl-2-pentene, 5- (2-propenyl)-
Examples thereof include compounds having a double bond other than the terminal such as 2-norbornene and capable of isomerizing at a more stable position.

The amount of the solid base catalyst used for producing the internal olefin is usually 1/3000 to 1/20 weight, and 1/2000 to 1/100 weight is sufficient with respect 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 -80 to 120 ° C, preferably -10 to 100 ° C
It is carried out in the temperature range of.

If necessary, the reaction can be carried out by diluting with an inert medium, for example, hydrocarbons such as pentane, hexane, heptane, dodecane, etc., but since the desired product can be obtained only by separating the catalyst after the reaction, no medium or It is preferable to select the solvent and the like used in the step.

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 and the like are analyzed by a known method such as gas chromatography, and easily separated from the catalyst by filtration, decantation or the like.

<Effects of the Invention> Thus, the internal olefin isomerized at a more stable position, which is the object of the present invention, can be obtained. However, according to the method of the present invention, an alkali metal hydride that can be easily handled and easily obtained can be used as a catalyst raw material. Moreover, the obtained catalyst has a remarkably high isomerization ability without auxiliary agents such as ammonia and hydrazine,
Even with a small amount of catalyst, the olefin isomerization reaction can be completed extremely efficiently, and in addition, internal olefin can be obtained in high yield without accompanying byproducts such as polymerized products. In addition, the reaction can be safely proceeded without danger of ignition and the like, which is extremely advantageous as an industrial production method of internal olefin.

<Example> The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

Reference Example 1 25.0 g of γ-alumina containing 2.2% by weight of water was placed in a 100 ml flask and sodium hydride was added in a nitrogen stream (after adding hexane to a commercial product under a nitrogen stream to wash and remove mineral oil. 1.28 g was added and the mixture was heated to 850 ° C. with stirring and stirred at the same temperature for 1 hour. Then, the mixture was allowed to cool to room temperature to obtain 25.9 g of a solid base.

Reference Examples 2 to 9 The solid bases shown in Table 1 were obtained in the same manner as in Reference Example 1 except that shown in Table 1.

Example 1 0.13 g of the solid base prepared in Reference Example 1 was placed in a 200 ml flask under a nitrogen atmosphere, 65.0 g of 5-vinyl-2-norbornene (purity 99.9%) was added thereto, and the mixture was heated at 15 to 20 ° C. for 15 hours. When stirred and the reaction solution was measured by gas chromatography, 5-vinyl-2-norbornene (VNB) 0.3%, 5-
It was 99.6% of ethylidene-2-norbornene (ENB). The catalyst was removed from the reaction solution to obtain 64.3 g of a product.

Examples 2 to 6 and Comparative Examples 1 to 3 The isomerization reaction was carried out in the same manner as in Example 1 except that the flask shown in Table 2 was used under a nitrogen atmosphere by using a 100 ml flask. The results are shown in Table-2.

Example 7 0.24 g of the solid base prepared in Reference Example 1 was placed in a 100 ml flask under a nitrogen atmosphere, and 5-isopropenyl-2- was added thereto.
Norbornene (End type 89.9%, Exo type 10.1%) 28.9
After adding g and stirring for 20 hours at 15 to 20 ° C., the reaction mixture was analyzed by gas chromatography to find that endo-5-isopropenyl-2-norbornene <0.1%, exo-5-
Isopropenyl-2-norbornene was 0.8% and 5-isopropylidene-2-norbornene was 99.8%.

Example 8 A glass tube having an outer diameter of 5 mmφ and a length of 100 mm with a jacket tube was filled with 0.95 g of the solid base prepared in Reference Example 1 under a nitrogen atmosphere.

Pour cooling water of 15 to 20 ° C into the outer tube, and from the top of the inner tube to 3.4g / h
VNB (purity 99.9%) was introduced at a flow rate of r.

The composition of the reaction liquid flowing out from the lower part of the reactor was as follows.

 Time (hr) VNB (%) ENB (%) 15 0.3 99.5 25 0.3 99.5 35 0.3 99.5 45 0.3 99.5 Total discharge 152.1g, ENB average purity 99.5%.

Example 9 In a 100 ml flask, under a nitrogen atmosphere, 0.25 g of the solid base prepared in Reference Example 1 was placed and 4-methyl-1-pentene 2
3.0 g was added, and the mixture was reacted at 15 to 20 ° C for 16 hours.

After the reaction, the reaction liquid was analyzed by gas chromatography to find that 4-methyl-1-pentene 0.4%, 4-methyl-2-pentene 9.2%, and 2-methyl-2-pentene 90.2.
%Met.

Example 10 In a 200 ml flask, under a nitrogen atmosphere, 0.24 g of the solid base prepared in Reference Example 5 was placed, and 4-methyl-1-pentene 8 was added thereto.
6.2 g was added and reacted at 15 to 20 ° C. for 8 hours.

After the reaction, the reaction solution was analyzed by gas chromatography to find that 4-methyl-1-pentene 0.3%, 4-methyl-2-pentene 9.8%, 2-methyl-2-pentene 89.9
%Met.

Comparative Example 4 Under a nitrogen atmosphere, 0.30 g of the solid base prepared in Reference Example 8 was placed in a 100 ml flask, and 4-methyl-1-pentene was added thereto.
6.4g was added and it reacted at 15-20 degreeC for 48 hours.

After the reaction, the reaction solution was analyzed by gas chromatography to find that 4-methyl-1-pentene 89.3%, 4-methyl-2-pentene 6.8%, 2-methyl-2-pentene 3.9%.
Met.

Comparative Example 5 Under a nitrogen atmosphere, 0.30 g of the solid base prepared in Reference Example 9 was placed in a 100 ml flask and 4-methyl-1-pentene 1 was added thereto.
5.3 g was added and reacted at 15 to 20 ° C. for 48 hours.

After the reaction, the reaction liquid was analyzed by gas chromatography to find that 4-methyl-1-pentene 0.6%, 4-methyl-2-pentene 27.9%, and 2-methyl-2-pentene 71.1.
%Met.

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Claims (1)

[Claims] 1. In the process of isomerizing an olefin to produce a more stable internal olefin, a hydrous alumina and an alkali metal hydride in an amount exceeding the equivalent amount to the molar amount of water of the alumina are used as a catalyst. A process for producing an internal olefin characterized by using a solid base obtained by heating in a temperature range of 200 to 500 ° C.