JPS5825655B2 - Isomerization method of diacetoxybutene - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for isomerizing diacetoxybutene.

More specifically, 3,4-diacetoxybutene-1 (hereinafter abbreviated as 3,4-DABE) is converted into 1,4-diacetoxybutene-2 (hereinafter abbreviated as 1,4-DABE), or The present invention relates to a method of isomerizing 1,4-DABE to 3,4-DABE, and particularly preferably relates to a method of isomerizing 3,4-DABE to the more useful 1,4-DABE.

Conventionally, there have been many methods for producing diacetoxybutene by reacting butadiene, acetic acid, and oxygen in the gas phase or liquid phase in the presence of a noble metal catalyst, such as a catalyst mainly composed of palladium, platinum, and rhodium. A method is proposed.

In this acetoxylation reaction, ■・4-DABE and 3・4-DABE
It is known that the production rate of

Among these, when 1,4-DABE is subjected to a treatment such as water addition and water decomposition, industrially useful compounds such as 1,4-butanediol and tetrahydrofuran can be obtained.

On the other hand, 3,4-DABE is a vinyl-based compound and has polymerizability, and can be used to modify vinyl polymers.

In the present invention, 3,4-DABE or 1,4-DABE is converted into 1,4-DABE or 3,4-D using a cation exchange resin.
The utilization efficiency of diacetoxybutene is increased by isomerizing it to ABE.

As a method for isomerizing diacetoxybutene, there is a method of isomerizing by a gas phase method using alumina as an isomerization catalyst, but this method has problems in selectivity and yield.

In addition, as a method for isomerization by a liquid phase method, a method using sulfuric acid (method 1), a method using a palladium compound or a platinum compound (method 2), a method using copper compounds (method 3), etc. have been proposed.

Among these methods, method 1 has problems such as low yield (and high boiling point by-products and equipment corrosion), and method 2 reduces the loss of expensive precious metals when separating the catalyst and product. In addition to problems, it is said that deactivation occurs due to metalization of the palladium compound that is the catalyst.

Method 3 has problems with catalyst separation and product yield.

As described above, various attempts have been made to isomerize 3,4-DABE or 1,4-DABE, but each has its own problems and cannot be said to be an industrially advantageous method.

An object of the present invention is to provide an isomerization method that solves these problems.

As a result of extensive research into the isomerization of diacetoxybutene, the present inventors have found that a highly effective cation exchange resin,
Using common substances, 3,4-DABE can be converted to 1,4-D.
We have discovered that good reaction results can be obtained when isomerizing ABE or 1,4-DABE to 3,4-DABE, and that the separation of the catalyst is extremely easy. The present invention was achieved by discovering that the reaction rate is greatly increased when the reaction is carried out below.

That is, the present invention provides 3,4-DABE or 1,4-DABE.
Provided are a method for isomerizing diacetoxybutene to produce 1,4-DABE or 3,4-DABE by contacting the diacetoxybutene with a cation exchange resin, and a method for carrying out the isomerization in the presence of acetic acid.

In the method of the present invention, 3,4-DABE or 1,4-D
The catalyst used in the ABE isomerization reaction is a cation exchange resin, and although not particularly limited, a strongly acidic cation exchange resin is preferable.

As the strongly acidic cation exchange resin, a sulfonic acid type strongly acidic cation exchange resin whose base material is a copolymer of styrene and divinylbenzene is particularly useful, and it may be a so-called gel type resin or a porous type resin.

The isomerization reaction of 3,4-DABE and 1,4-DABE is an equilibrium reaction. For example, at 120°C, 3,4-DABE
ABE: 1.4-DABE=30:70 (molar ratio) is approximately the equilibrium composition.

Therefore, 3,4-DABE or 1,4-DABE used for isomerization
Pure DABE may be used, but 3,4-DABE or 1,4-DABE has a higher equilibrium composition at the reaction temperature.
If it contains DABE, 1・4-DABE or 3
・There is no problem even if it contains 4-DABE.

Of course, the reaction can also be carried out in a diluted state with an organic solvent and/or water.

As a reactor for carrying out the method of the present invention, a fixed bed reactor, a flow reactor, a heterogeneous liquid phase batch reactor, etc. can be used as appropriate.

The reaction temperature is not particularly limited, but is preferably 120 to 80°C in consideration of the thermal stability and activity of the cation exchange resin.

The reaction pressure is also not particularly limited, and can be widely employed from normal pressure to elevated pressure.

The contact time between the raw material and the catalyst is determined by the amount of 3,4-DABE in the raw material.
Or, it depends on the concentration of 1,4-DABE and the target concentration of 3,4-DABE or 1,4-DABE after isomerization, reaction temperature, catalyst concentration, etc. 3 Therefore, the contact time, the concentration of 3,4-DABE in the raw material, etc. The concentration of 4-DABE or 1,4-DABE, the isomerization rate, the reaction temperature, and the catalyst concentration can be appropriately selected in consideration of economic efficiency.

Acetic acid found as an activity-promoting component is 3,4-DABE.
Alternatively, even if 1 part by weight is added to 100 parts by weight of 1,4-DABE, the reaction rate increases by about 15%.

When 200 parts by weight is added, the reaction rate increases by about 300%, but even if more than that is added, almost no new addition effect is observed.

The amount of acetic acid to be added can be determined by taking into account such results and economic efficiency such as the separation of acetic acid after the isomerization reaction and the amount of isomerization.

The amount is preferably in the range of 0.1 to 200 parts by weight per 00 parts by weight of DABEl.

Of course, if economic efficiency is ignored, it is possible to add 200 parts by weight or more; for example, even if 500 parts by weight is added, the isomerization reaction can be promoted.

In addition, since acetic acid has an effect as an activity-promoting component, for example, when separating 3,4-DABE or 1,4-DABE to be isomerized from the reaction solution obtained by acetoxylating butadiene, the by-produced acetic acid can be removed. 3/4-DABE or 1
・Can be added to 4-DABE (3・4-D
It is also possible to obtain the effect that it is not necessary to carry out severe distillation separation of ABE or 1,4-DABE and acetic acid.

Furthermore, the cation exchange resin used as a catalyst in the present invention can easily recover its catalytic activity by treatment with hydrochloric acid, which is very advantageous in the isomerization process.

As described above, according to the present invention, 3,4-DABE or 1,4'=DABE can be converted to 1,4 by a very simple method using a very common substance called cation exchange resin.
-DABE or 3,4-DABE can be industrially advantageously isomerized.

Percentages in the following examples are by weight unless otherwise stated.

Example 1 75.0% 3・4-DABE and 25.0% 1・4-DABE
100 g of a mixed solution containing DABE was charged into a 300 CC glass autoclave, and converted to H type using a cation exchange resin (a sulfone-type strongly acidic cation exchange resin whose base material is styrene-divinylbenzene copolymer).

Amberlite 200C) 2Of, trade name Organo (trade name), was introduced and reacted at 120°C.

When the reaction solution was analyzed after 1 hour, it was found that 1,4-DABE
The percentage is 31.0%, and after 3 hours, it is 40.8%.
When the reaction was stopped and the diacetoxybutenes were recovered, 97.0P was obtained.

Example 2 A reaction was carried out in exactly the same manner as in Example 1, except that 40 g of acetic acid was added.

When the reaction solution was analyzed after 1 hour, it was found that 1,4-DABE
The percentage is 40.0%, and after 3 hours, it is 56.6%.
had reached.

Then, the reaction was stopped and diacetoxybutenes were collected, and 97.3P was obtained.

Example 3 90.0% 3・4-DABE and 10.0% 1・4-DABE
A mixed solution containing DABE was filled with 100 g of the same cation exchange resin as in Example 1, with an inner diameter of 20 mm and a length of 400 m.
m glass flow-through reaction tube at a rate of 100 g/hour,
It was supplied from the bottom of the reaction tube and reacted continuously at 120°C.

Analysis of the reaction solution flowing out from the top of the reaction tube revealed that 1.
The percentage of 4-DABE reached 44.6%.

Example 4 1・4-DABE of 25.01 and 25.0? of acetic acid was placed in a glass flask, 10 g of the same cation exchange resin as in Example 1 was added, and the mixture was reacted at 120°C.

When the reaction solution was analyzed after 1 hour, it was found that 3,4-DABE
The ratio is 16.5%, and after 3 hours,
% has been reached.

Comparative Example 1 A reaction was carried out in exactly the same manner as in Example 2, except that the cation exchange resin was omitted.

Analysis of the reaction solution after 3 hours revealed that 1,4-DABE
The percentage did not change at all.

Claims (1)

[Claims] By contacting 13,4-diacetoxybutene-1 or 1,4-diacetoxybutene-2 with a cation exchange resin, 1
- A method for isomerizing diacetoxybutene to produce 4-diacetoxybutene-2 or 3,4-diacetoxybutene-1. 2 Claim 1 in which isomerization is performed in the presence of acetic acid
The method described in section.