JPH1077277A - Method for producing cyclic alpha, beta-unsaturated ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a cyclic α,β-unsaturated ether useful as an intermediate for various kinds of medicines and agrochemicals at high productivity and high conversion and selectivity by performing dehydrogenation and dehydration of an alkane diol in the presence of a cobalt catalyst. SOLUTION: This cyclic α,β-unsaturated ether is produced by reacting an alkanediol of the formula, HO(CH2 )2 X(CH2 )2 OH (X is a single bond, methylene, ethylene, ethylidene or 0) at 210-250 deg.C in the presence of a cobalt-containing catalyst, an organic sulfonic acid and a high boiling amine to dehydrogenate and dehydrate the alkanediol. A catalyst in which cobalt, cobalt oxide and zirconium is supported on diatomaceous earth is preferable as the catalyst, and the catalyst is used in an amount of 0.01-0.3wt.% based on the alkanediol in terms of pure cobalt. The use of the organic sulfonic acid is 0.001-0.1wt.% based on the alkanediol, and the high boiling amine is used in an amount of 1-10mol based on 1mol of the organic sulfonic acid. The amount of distillation of the cyclic α,β-unsaturated ether per unit catalyst is about 50g/g-catalyst for 1hr, and it is clear that the catalyst has high activity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing an α, β-cyclic unsaturated ether. The α, β-cyclic unsaturated ether produced according to the present invention is useful as an intermediate for various medicines and agricultural chemicals.

[0002]

2. Description of the Related Art Conventionally, as a method for producing an α, β-cyclic unsaturated ether, 2,4-dihydrofuran is produced by treating 1,4-butanediol with a catalyst containing metallic cobalt. Method (Japanese Patent Publication No. 35-16566)
Reference), 1,4-butanediol or 1,5-butanediol
A method for producing a corresponding α, β-cyclic unsaturated ether by treating pentanediol with metallic cobalt having a specific crystal structure (see Japanese Patent Publication No. 8-9605) is known.

[0003]

However, when the amount of product distilled out per unit catalyst is determined by the above method, the amount of each product is about 0.4 g / g catalyst per hour.
Its catalytic activity is low. Therefore, in order to increase the productivity, a large amount of a catalyst and a large reactor are required. Therefore, these methods are not said to be industrially advantageous methods for producing an α, β-cyclic unsaturated ether. Accordingly, an object of the present invention is to provide a method for industrially and advantageously producing an α, β-cyclic unsaturated ether with high productivity and high conversion and selectivity.

[0004]

According to the present invention, the above objects have been achieved by the general formula (I)

[0005]

Embedded image

An alkanediol represented by the formula (wherein X represents a single bond, a methylene group, an ethylene group, an ethylidene group or an oxygen atom) [hereinafter abbreviated as alkanediol (I)] contains cobalt. This is achieved by providing a process for producing an α, β-cyclic unsaturated ether, which comprises dehydrogenating and dehydrating in the presence of a catalyst, an organic sulfonic acid and a high-boiling amine.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the production method of the present invention may contain cobalt, and may be a metal cobalt alone or a supported catalyst having metal cobalt supported on a carrier. . The simple substance of metallic cobalt includes Raney cobalt, reduced cobalt and the like. Examples of the carrier include silica gel, alumina, and diatomaceous earth.
If necessary, other co-catalysts can be used in combination. As the co-catalyst, a metal such as chromium, zinc, copper, silver, palladium, or zirconium is used. As the catalyst containing cobalt used in the present invention, a supported catalyst is preferable, and a catalyst in which cobalt, cobalt oxide and zirconium are supported on diatomaceous earth is more preferable.

[0008] The amount of the catalyst containing cobalt is as follows with respect to the alkanediol (I) at the time of initial charging.
It is preferable to have an amount in the range of 0.01 to 0.3% by weight as a pure cobalt content in the reaction system. When the alkanediol (I) is continuously or sequentially added to the reaction system, the above catalyst may be added continuously or sequentially according to the addition.

As the organic sulfonic acid, an alkanesulfonic acid such as methanesulfonic acid and ethanesulfonic acid; an arylsulfonic acid such as benzenesulfonic acid and p-toluenesulfonic acid and hydrates thereof are used.
The amount of the organic sulfonic acid used is 0.001 to 0.1% by weight based on the alkanediol (I) during the initial preparation.
Is preferably present in the reaction system. When the alkanediol (I) is continuously or sequentially added to the reaction system, the above organic sulfonic acid may be continuously or sequentially added according to the addition.

A high-boiling amine has a boiling point of 250 at normal pressure.
It means an alkylamine having a temperature of not less than ° C. As the high boiling point amine, for example, trioctylamine, di (2-ethylhexyl) amine and the like are used. The amount of the high-boiling amine is preferably in the range of 1 to 10 mol per 1 mol of the organic sulfonic acid.

[0011] The reaction temperature is preferably in the range of 210 to 250 ° C, more preferably in the range of 225 to 235 ° C.

The reaction is preferably carried out under the reflux condition of the raw material alkanediol (I), and the alkanediol (I) may be continuously or sequentially added to the reactor in accordance with the distillation. . The α, β-cyclic unsaturated ether distilled off together with water and hydrogen by the reaction is condensed in a cooler, separated from water, and can be easily isolated by distillation.

According to the present invention, α, β per unit catalyst
The distillation of cyclic unsaturated ethers is about 50 per hour;
g / g catalyst.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Example 1 Catalyst supporting cobalt, cobalt oxide and zirconium on diatomaceous earth (G-67; manufactured by Nissan Gardler Co.) 8
9.5 mg and 50 g of 1,4-butanediol
(0.556 mol) was heated at a bath temperature of 250 ° C. and an internal temperature of 225 to 228 ° C. for 2 hours while flowing nitrogen at a flow rate of 20 ml / min. During the reaction, 3.6 g of 1,4-butanediol
(0.04 mol) was added in three portions. The distillate was mainly water and the amount was 1.99 g. After cooling the reaction solution to 60 ° C., p-toluenesulfonic acid monohydrate5.
6 mg and trioctylamine 41.6 mg were added,
While flowing nitrogen at a flow rate of 5 ml / min, a bath temperature of 260 ° C.
It heated to internal temperature 228-230 degreeC. 1,4-butanediol was fed in accordance with the amount of distillate, and the reaction was stopped after 5 hours. The amount of 1,4-butanediol fed in 5 hours was 47.55 g (0.528 mol).
2,3-dihydrofuran in the obtained distillate was 28.4.
2 g (0.470 mol). The yield of 2,3-dihydrofuran calculated by subtracting 1,4-butanediol and acetal (both corresponding to 0.621 mol of 1,4-butanediol) in the kettle solution was 75%.

EXAMPLE 2 233 mg of a catalyst (G-67; manufactured by Nissan Gardler Co.) supporting cobalt, cobalt oxide and zirconium on diatomaceous earth, and 8.4 of p-toluenesulfonic acid monohydrate
The reaction was carried out in the same manner as in Example 1 except that 62.4 mg of trioctylamine, 132.5 g (1.472 mol) of 1,4-butanediol were used, and the reaction time was changed to 8 hours. The catalyst was added while appropriately adding to the reaction system, and the above amount was used in total. 2, in the obtained distillate
The amount of 3-dihydrofuran was 46.87 g (0.67 mol). The yield of 2,3-dihydrofuran calculated by subtracting 1,4-butanediol and acetal (both corresponding to 0.683 mol of 1,4-butanediol in the kettle solution) was 85%.

Example 3 8 g of cobalt oxide, 0.4 g of zinc oxide and 11.6 g of silica gel were mixed, and this was mixed at 450 ° C. under a hydrogen stream.
Heated for hours. The obtained catalyst (1.83 g), p-toluenesulfonic acid monohydrate (12.8 mg), di (2-ethylhexyl) amine (25.6 mg) and 1,5-pentanediol (35.6 g) were mixed, and the mixture was stirred at 230 ° C. for 1 hour. Upon heating, 17.65 g of an organic layer containing 16.94 g (0.201 mol) of 2,3-dihydropyran was obtained. The yield of 2,3-dihydropyran calculated by subtracting 1,5-pentanediol and acetal (both corresponding to 0.129 mol of 1,5-pentanediol) in the kettle solution is 9
4%.

[0018]

According to the present invention, an .alpha.,. Beta.-cyclic unsaturated ether can be industrially advantageously produced with high productivity, while maintaining high conversion and selectivity.

Claims (1)

[Claims] 1. A compound of the general formula (I) (Wherein X represents a single bond, a methylene group, an ethylene group, an ethylidene group or an oxygen atom), by dehydrogenating the alkanediol in the presence of a cobalt-containing catalyst, an organic sulfonic acid and a high boiling amine And a method for producing an α, β-cyclic unsaturated ether, characterized by dehydration.