JPS6296434A - Production of 5-ethylidene-2-norbornene - Google Patents

Abstract

PURPOSE:To advantageously obtain the titled compound, by using a solid base catalyst obtained by reacting alumina with an alkali metal hydroxide and a alkali metal successively at respectively specific temperature conditions while heating in isomerization of 5-vinyl-2-norbornene. CONSTITUTION:In producing the titled compound useful as the third component of ethylene.propylene.diene monomer-terpolymer (synthetic rubber) by isomerizing 5-vinyl-2-norbornene, a solid base catalyst obtained by reacting alumina with an alkali metal hydroxide while heating at 200-500 deg.C, especially 250-450 deg.C, and further reacting thus obtained product with an alkali metal while heating at 200-350 deg.C, especially 200-330 deg.C, is used to industrially and advantageously obtain the titled compound. According to this method, the reaction can be finished extremely effectively even with a little amount of catalyst and the aimed compound can be obtained safely in high yield without side- reaction of polymer, etc., and danger of ignition, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 5-ethylidene-2-norbornene.
- A method for producing 5-ethylidene-2-norbornene (hereinafter abbreviated as ENB), which is characterized by isomerizing norbornene (abbreviated as VNB under Jd).

END is an extremely useful compound as the third component of the synthetic rubber ethylene-propylene-diene monomer terpolymer, so-called EPDM. It is produced by isomerization in the presence of

As a catalyst for such an isomerization reaction, a limb-like base such as a mixture of an alkali metal hydroxide and an aprotic organic solvent, an alkali metal amide and amines, or an organic alkali metal and an aliphatic amine is known. However, in the method using such a dispersed base reagent, the catalytic activity is not sufficient and a large number of expensive reagents are required. This is a difficult process, not only requiring a complicated separation and recovery process but also consuming a large amount of energy.

In addition, as solid isomerization catalysts, catalysts in which alkali metals are dispersed in carriers with large surface areas, such as activated carbon, silica gel, alumina, etc., are known (J, Ax
ll, (jhem, (jhem, 8oc, 8288
7 (1960)).

However, in such a solid catalyst, the alkali metal itself is simply finely dispersed in the carrier L, and when it comes into contact with air, it ignites and becomes deactivated, so it takes a long time in terms of operability and safety. There was a spoon.

Also, the isomerization ability was unsatisfactory.

The present inventors have already discovered a new catalyst using alumina, an alkali metal hydroxide, and an alkali metal as raw materials as an efficient catalyst that does not have the opening problems of isomerization catalysts. does not pose any danger of ignition even in the air.
It has been found that it is safer and industrially superior as an isomerization catalyst for 4-refins such as VNB (
Special Publication No. 5 (No. 1-8274).

The present inventors conducted further research on the isomerization of VNB using such a solid base catalyst, and found that the preparation temperature at which the raw materials alumina, alkali metal hydroxide, and alkali metal are reacted, especially the alkali metal The temperature at which the reaction is carried out is particularly important, and if the catalyst is heated under a specific temperature, the catalytic activity will be significantly improved. The invention was completed 17 years ago.

Of course, the present invention involves heating alumina and alkali metal hydroxide at 200 to 500"C to produce 5-ethylene 2-norbornene by isomerizing 5-vinyl-2-norbornene. Provided is an industrially excellent method for producing 5-vinyl-2-norbornene, which is characterized by using a solid base catalyst which is treated with an alkali metal and then heated at a temperature of 200"0 to less than 850"C. It is something to do.

As the alkali metal that is a raw material for the solid base catalyst in the present invention, an alkali metal belonging to Group 1 of the periodic table is used, and sodium, potassium, or an alloy thereof is preferably used. Also, examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, and water M.
Rubidium chloride, cesium hydroxide, etc. are used, and the form thereof may be solid, liquid, or aqueous solution.

Regarding combinations of alkali metals and alkali metal hydroxides, combinations of alkali metals and corresponding alkali metal hydroxides, such as sodium and sodium hydroxide, potassium and potassium hydroxide, etc., are preferred; Combinations of metals and other alkali metal hydroxides that do not correspond to the metals, such as potassium and sodium hydroxide, sodium and potassium hydroxide, and sodium and lithium hydroxide, may also be used, but industrially, combinations of sodium hydroxide and metallic sodium are used. is preferred. From the viewpoint of catalytic activity, the alkali metal and alkali metal hydroxide are preferably used in a 2- to 10-heavy form and a 5- to 40-heavy form, respectively, with respect to alumina.

As the alumina, various forms of alumina having a large surface area are usually used, but it is particularly preferable to use γ-alumina of 100 to 800 mesh from the viewpoint of catalytic activity. In addition, alumina interacts with alkali metals and alkali metal hydroxides to form new bonds that interact with H, and also plays the role of a carrier. Alumina, as described above, is preferred, although it can be used.

The catalyst used in the present invention is obtained by reacting alumina, alkali metal hydroxide, and alkali metal as described above at a specific temperature in an inert gas atmosphere, but the order in which they are reacted is as follows: It is most preferable to first treat alumina with an alkali metal hydroxide and then with an alkali metal. Examples of the inert gas include nitrogen, helium, and argon.

For the catalyst used in the present invention, the temperature at which the catalyst is prepared is extremely important, and in particular, the temperature at which the alkali metal is applied has a significant influence on the activity of the catalyst.

The temperature at which alumina and alkali metal hydroxide are allowed to react is 200 to 500°C, preferably 250 to 45°C.
0°C, and the temperature at which the alkali metal acts is 20°C.
0"C or more and 850"('!, preferably less than 2
00 to 880''C.

By preparing a catalyst at such a temperature, a catalyst with extremely high activity never seen before can be obtained, and the desired reaction can be efficiently completed with a small amount of catalyst 1.

The heating time varies depending on the selected temperature conditions, etc., but the process of applying an alkali metal hydroxide usually takes 0.5 to 1
0 hours is sufficient, and 10 to 800 minutes is usually sufficient for the step of oxidizing the alkali metal.

In this way, compared to known solid base catalysts, a catalyst can be obtained that is safe without the risk of ignition and has significantly higher activity.

The present invention uses such a solid base catalyst to isomerize VNB to ENB, and the amount of such solid base catalyst used is usually 1/8,000 to 1,750 times the amount of VNB.
Heavy weight, preferably 1/2. On(] to 1/10
(1 weight. Regarding the isomerization temperature, the reaction proceeds sufficiently even at room temperature, so there is no particular need to heat it, but depending on the purpose, it may be heated. Usually -80 to 120°C
, preferably at a temperature range of -10 to 100''C.

If necessary, the reaction can be carried out by diluting with an inert medium such as a hydrocarbon such as pentane, hexane, heptane, dodecane, etc., but no medium is sufficient. The method of the present invention can be carried out either batchwise or continuously, and for isomerization,
It is also effective to pre-treat VNB with a desiccant such as alcohol. In order to carry out isomerization more safely and reliably, 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.

In this way, ENB, which is the object of the present invention, is obtained, but the method of the present invention is extremely efficient (the isomerization reaction of VNB can be completed, and the isomerization reaction of VNB can be completed, and the isomerization reaction of E in high yield without by-products
NB is obtained. Moreover, since the reaction can proceed safely without any dangers such as ignition, END
It is extremely useful as an industrial manufacturing method.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited only to the examples.

Example 1 Put γ-alumina 81.9F into a 100-ml flask,
The temperature was raised to 490 to 600°C under nitrogen gas flow, and the mixture was stirred at the same temperature for 1 hour. 4. Lower the temperature to 800-810"C.
5j' of sodium hydroxide was added and stirred at the same temperature for 8 hours.

Next, 1.5f of metallic sodium was added, and 1.5f of sodium was added at the same temperature.
After stirring for an hour, the mixture was cooled to room temperature to obtain a solid base of 84.9F.

Example 1 5-vinyl-2-norbornene (
82.5f (hereinafter abbreviated as VNB) was added, and after nitrogen substitution, 0.25F of the solid base prepared in Reference Example 1 was added.
The mixture was stirred at 20°C for 6 hours.

The catalyst was then filtered to obtain an 81.9N reaction solution. When this product was analyzed by gas chromatography, it was found that VNBo was 5% and 5-ethylidene norbornene (hereinafter abbreviated as ENB) was 99.4%.

Reference Example 2 Put r-alumina 81.9F into a 100s+j flask and! The temperature was raised to 490 to 500°C under X gas flow, and the mixture was stirred at the same temperature for 1 hour. The temperature drops to 800-810°C8
．． Of sodium hydroxide was added and stirred at the same temperature for 8 hours.

Next, 1.2f of metallic sodium and 0.8g of metallic potassium were added and stirred at the same temperature for 0.6 hours, and then cooled to room temperature to obtain a solid base of 88.8F.

Reference examples 8 to 10 The condition sequence shown in Table 1 is the same as in Reference Example 1 (lO) The solid base catalysts shown in Table 1 were obtained.

Examples 2 to 8, Comparative Example 1.2 Using the solid base catalysts prepared in Reference Examples 2 to 8 and 9 and 1o, VN was prepared in the same manner as in Example I except for the conditions shown in Table 2.
Isomerization of B was performed.

The results are shown in Table 2.

Claims (1)

[Claims] In isomerizing 5-vinyl-2-norbornene to produce 5-ethylidene-2-norbornene, alumina and an alkali metal hydroxide are heated at 200 to 500°C, and then the alkali metal is heated at 200°C to 350°C.
1. A method for producing 5-ethylidene-2-norbornene, which comprises using a solid base catalyst heated at a temperature below .degree.