JPH02188544A - Production of allyl vinyl ether - Google Patents

Abstract

PURPOSE:To enable the continuous production of the subject compound from acetaldehyde diallyl acetal over a long period and to obtain the objective compound on an industrial scale at a low cost by dealcoholating the above raw material in an organic solvent having high boiling point and containing a strong acid. CONSTITUTION:Allyl vinyl ether useful as a raw material for various functional polymers can be produced on an industrial scale at a low cost by dealcoholating acetaldehyde diallyl acetal in a high-boiling organic solvent (e.g. glyceroI triacetate, octyl oleate, ethyl di- or triglycol acetate, liquid paraffin, alkylbenzene or arylbenzene) containing a strong acid (e.g. phosphoric acid. sulfuric acid or p-toluenesulfonic acid, especially phosphoric acid). The catalytic activity can be maintained over a long period by dissolving a small amount of the catalyst (strong acid) in the raw material or mixing the solvent with additional catalyst when the catalytic activity is lowered after a long-term operation.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for producing allyl vinyl ether.

Allyl vinyl ether is a compound useful as a raw material for various functional polymers.

<Prior art> USP 37059 describes a method for producing allyl vinyl ether from acetaldehyde diallyl acetal.
24.3021373, etc., and gas phase methods and reactive distillation methods have been proposed.

<Problem to be Solved by the Invention> As a result of the present inventors' study of the method disclosed in the above patent, it was found that there are some obstacles to commercialization.

First, according to US Pat. No. 3,705,924, it has been reported that allyl vinyl nitride is produced from acetaldehyde diallyl acetal by a gas phase catalytic reaction.

According to the method disclosed in this patent, the product allyl vinyl ether has poor thermal stability and is easily isomerized.
Become a pentenal.

Therefore, in the method disclosed in this patent, allyl vinyl ether is diluted with a large amount of insoluble gas and brought into contact with a catalyst in a short period of time, so that the conversion rate of allyl vinyl ether to acetaldehyde diallyl acetal is 95.5%, and the allyl vinyl ether selectivity is 8.
A result of 6.5% was obtained.

However, in this method, since a large amount of inert gas is used, the concentration of allyl vinyl ether, which is the target product, is only about 1.8% in the mixed gas, and allyl vinyl ether, which is a relatively low boiling point product, has a relatively low boiling point. It is difficult to collect helium, expensive helium is used as an inert gas, and the space-time yield is only 56 t/hour/catalyst.The catalyst activity is also degraded. As such, it is not satisfactory.

Further, according to US Pat. No. 3,021,373, allyl vinyl ether is produced from acetaldehyde diallyl acetal by a reactive distillation method using a strong acidic catalyst.

The method disclosed in this patent is to put acetaldehyde diallyl acetal into a pot of a distillation column, heat it, and when the acetaldehyde diallyl acetal starts to boil, add a catalyst, and then continuously feed the raw material acetaldehyde diallyl acetal to produce allyl vinyl ether. Manufacture.

Allyl vinyl ether was obtained in a yield of 82% after 12.4 hours of continuous operation by adding a catalyst during the reaction to maintain the activity when the catalyst activity decreased.

However, as a result of our repeated experiments, we found that with this method, the catalyst activity was severely reduced and no matter how much catalyst was added, the reaction no longer proceeded.

In the case of the method disclosed in this patent, a batch method is employed in which the reaction is stopped after a certain period of time, perhaps for the purpose of preventing this.

However, when this method is industrialized, the operation is extremely complicated and is by no means satisfactory.

Means for Solving the Problems> As a result of intensive studies to solve the problems of the prior art, the present inventors have developed an industrially superior allyl which is carried out in a high-boiling heating medium containing a catalyst. I discovered a method for producing vinyl ether.

That is, the present invention is a method for producing allyl vinyl ether, which is characterized in that, in producing allyl vinyl ether from acetaldehyde diallyl acetal, the process involves acetaldehyde in a high-boiling solvent containing a strong acid and dealcoholizing the diallyl acetal. .

The present invention will be explained in detail below.

In the method of the present invention, the reaction is an equilibrium reaction as shown in the following reaction formula.

CH3CH (CH2=CH-CH,0) 2r acetalde diallyl acetal" CH to CH-OH20H r allyl alcohol 1 + CH=CH-CH20CH=CH2 r allyl vinyl ether" Carrying out the method for producing allyl vinyl ether of the present invention In this case, acetaldehyde diallyl acetal is fed into a heated high-boiling heating medium containing a catalyst, and the reaction is allowed to proceed in the heating medium.

Next, allyl vinyl ether, which is the target product, is extracted in the gas phase and then cooled to collect allyl vinyl ether.

The high boiling point heating medium used when carrying out the production method of the present invention needs to have a boiling point higher than the reaction temperature and higher than that of acetaldehyde diallyl acetal, which is the raw material.

In addition, the high boiling point heat transfer medium is inert to the starting material acetaldehyde diallyl acetal, the target product allyl vinyl ether, the by-product allyl alcohol, and the catalyst, and is also thermally stable. It must be.

Examples of such high boiling point heating medium include esters of higher alcohols and higher acids, aliphatic or aromatic alicyclic hydrocarbons, and the like.

Specific examples include glycerin triacetate, octyl oleate, ethyl diglycol acetate, ethyl triglycol acetate, liquid paraffin, alkylbenzene, and arylbenzene.

The high boiling point heat medium mentioned here is just an example, and any medium having the above-mentioned characteristics can be used. Examples of the strong acidic catalyst used include phosphoric acid, sulfuric acid, and P-toluenesulfonic acid, but phosphoric acid is particularly excellent as a catalyst.

The concentration of the catalyst varies depending on the acid used, but is generally preferably from 0.1 to 10%.

If it is less than 0.1%, the conversion rate of acetaldehyde diallyl acetal as a raw material decreases, which is not preferable.

Moreover, if it exceeds 10%, although the conversion rate of the raw material acetaldehyde diallyl acetal is improved, polymerization and isomerization of allyl vinyl ether proceed, which is not preferable.

The feeding rate of raw materials varies depending on the catalyst concentration, reaction temperature, reaction pressure, etc., but generally it is 0.000000000000000 yen per hour relative to the heating medium.
A range of 0.01 to 0.5 parts is preferred.

If the supply rate is low, manufacturing capacity will decrease and
This also increases side reactions, which is not preferable.

Moreover, if the feed rate is 0.5 or more, the rate of change of the raw material acetaldehyde diallyl acetal decreases, which is not preferable.

However, the magnitude of the rate of change is often determined by other requirements and is not particularly limited, and the most economical charging speed should be selected at the time.

The reaction temperature varies depending on the type and concentration of catalyst, reaction pressure, raw material supply rate, etc., but is generally preferably in the range of 100 to 200°C.

When the temperature is 100° C. or lower, the selectivity to allyl vinyl ether improves, but the conversion rate of the raw material acetaldehyde diallyl acetal decreases, which is not preferable.

Further, if the temperature is 200° C. or higher, although the rate of change of the raw material acetaldehyde diallyl acetal is improved, it is not preferable because it causes a decrease in selectivity due to isomerization of allyl vinyl ether.

The reaction pressure can be carried out at normal pressure, reduced pressure, or increased pressure, but the preferred pressure is from normal pressure to 50 flg).

If the pressure is high, the solubility in the heating medium increases and the raw materials such as acetaldehyde diallyl acetal, allyl vinyl ether, allyl alcohol, etc. change into substances other than the intended ones in the heating medium, which is not preferable.

If the pressure is low, the conversion rate of the raw material acetaldehyde diallyl acetal decreases, and furthermore, the boiling point of the product allyl vinyl ether decreases, making collection difficult, which is not preferable.

If the catalyst activity decreases during long-term operation, the activity can be maintained by adding more catalyst by dissolving a small amount of the catalyst in the raw material or by adding a mixture of the heating medium and the catalyst.

<Effects of the Invention> According to the present invention, it is possible to operate continuously for a long period of time, and it is possible to industrially produce allyl vinyl ether very advantageously.

<Example> Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 400 t of glycerin triacetate and 20 g of 85% phosphoric acid as a catalyst were charged into a cylindrical reaction tube with a length of 500 mm and an inner diameter of 45 + mφ, and the mixture was heated to 150 m under a reduced pressure of 20 Or@mHg.
Heat to ℃.

Acetaldehyde diallyl acetal is continuously charged at a rate of 40 g/hour, and the product gas is continuously extracted from the upper part of the reactor to cool the product gas to obtain a reaction product liquid.

Gas chromatography analysis of the reaction product solution revealed that 57.9% of the charged acetaldehyde diallyl acetal had changed.

Of the reacted acetaldehyde diallyl acetals, 8
8.2% was converted to allyl vinyl ether and 98.0% was converted to allyl alcohol.

Example 2 The reaction was carried out under the same conditions as in Example 1, except that the feed rate of the acetaldehyde diallyl acetal in Example 1 was changed to 160 r/h.

Rate of change of acetaldehyde diallyl acetal 27.4
%, a selectivity of 97.7% for allyl vinyl ether and a selectivity of 99.3% for allyl alcohol were obtained.

Comparative Example 1 Comparative example 1 was carried out under the same conditions as in Example 2 except that the amount of phosphoric acid in Example 2 was changed to 80 g.

As a result, the conversion rate of acetaldehyde diallyl acetal was 39.2%, and the selectivity of allyl vinyl ether was 75.
At 1%, the selectivity of allyl alcohol is 124.3%, and allyl alcohol is further produced as a by-product from the produced allyl vinyl ether.

Example 3 The phosphoric acid concentration of Example 1 was changed to 1%, and the reaction pressure was 100 maJ.
The reaction was carried out under the same conditions as in Example 1, except that 1 was changed. As a result, 5 hours after the start of the reaction, the change rate of acetaldehyde diallyl acetal was 45.6%, the allyl vinyl ether selectivity was 83.7%, and the allyl alcohol selectivity was 103.
8% was obtained.

After 50 hours, acetaldehyde diallyl acetal conversion rate was 44.5% and allyl vinyl ether selectivity was 83.2.
%, and the allyl alcohol selectivity was 105.2%.

Example 4.5 A reaction was carried out under the same conditions as in Example 3 except that the reaction pressure in Example 3 was changed. As a result, the following values were obtained.

Example 6.7 The reaction was carried out under the same conditions as in Example 3, except that the reaction temperature in Example 3 was changed.

As a result, the following values were obtained.

Example 8 The experiment was carried out under the same conditions as in Example 4 except that the feed rate of the raw material acetaldehyde diallylacetal was changed to 20 g/hour.

As a result, the change rate was 59.2%, the allyl vinyl ether selectivity was 88.8%, and the allyl alcohol selectivity was 99.2%.
Met.

Claims (1)

[Claims] A method for producing allyl vinyl ether, which comprises dealcoholizing the acetaldehyde diallyl acetal in a high-boiling organic solvent containing a strong acid.