JPS6033374B2 - Selective production method of 1,4-diacyloxybutene-2 - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 1,4-diacyloxybutene-2.

Specifically, the present invention relates to a method for producing 1,4-diacyloxybutene-2 by oxidizing 1,3-butadiene with molecular oxygen in the presence of a carboxylic acid.

1,4-Diacyloxybutene-2 becomes 1,4-butanediol by hydrogenation and hydrolysis, and is an extremely important raw material industrially.

Conventionally, various methods for producing 1,4-diacyloxybutene-2 by oxidative acyloxylation reaction of 1,3-butadiene have been proposed. However, these known methods have the disadvantage that 3,4-diacyloxybutene-1, which is of little industrial value, is produced as a significant by-product, and it is difficult to say that it is an industrially advantageous production method.

For example, according to Example 1 of the published patent publication No. 48-72090 and Example 1 of the published patent publication No. 50-140406,
The production ratio of 1,4-diacetoxybutene-1 is 86 for each
:14 peel 81:19.

Therefore, in order to increase the yield of 1,4-diacyloxybutene-2, it is necessary to create 3,4-diacyloxybutene-2.
It is necessary to isomerize 1 to 1,4-diacyloxybutene-2, and in fact, this isomerization method has also been proposed (for example, Japanese Patent Publication No. 47-30610 and Japanese Patent Publication No. 50-126611).

However, isomerization increases the number of steps and is extremely disadvantageous from an industrial perspective. Moreover, 3,4-diacyloxybutene-1 is a type of vinyl compound and tends to cause side reactions such as polymerization reactions, and the isomerization yield to 114-diacyloxybutene-2 is also unsatisfactory.

The inventors of the present invention have conducted intensive studies to overcome these drawbacks by using a novel composite catalyst consisting of radium metal and 'ii' organic iodide as a catalyst.
The present invention was achieved by discovering an industrially advantageous method for producing 4-diacyloxybutene-2.

That is, the present invention provides a novel method for producing 1,4-diacyloxybutene-2 by reacting 1,3-butadiene with carboxylic acid and molecular oxygen using a composite catalyst consisting of palladium metal and an organic iodide. This is what we provide.

According to the method of the present invention, the selectivity of 1,4-diacyloxybutene-2 in the diacyloxybutene produced is extremely high, and the amount of 3,4-diacyloxybutene-1 produced is extremely small and substantially It is possible to produce only 1,4-diacyloxybutene-2. The first catalyst used in the present invention
The component is palladium metal and the second component is an organic iodide.

The organic iodide of the second catalyst component is not particularly limited, and monovalent aliphatic iodides, monovalent aromatic iodides, polyvalent aliphatic iodides, polyvalent aromatic iodides, etc. are used. Examples of these include methyl iodide, ethyl iodide, normal propyl iodide, isopropyl iodide, normaltyl iodide, tert-butyl iodide, isoamyl iodide, normal hexyl iodide, normal octyl iodide, and normal iodide. Decyl, normal lauryl iodide, hexadecyl iodide, phenyl iodide, 1-naphthyl iodide, 2-naphthyl iodide, pendyl iodide, cyclohexyl iodide, ethylene iodohydrin, tetraethylene iodohydrin, propylene iodide -dohydrin, 1,2-diiodoethane, 1,2-diiodopro/gun, o-diiodobenzene, m-jodobenzene, p-jodobenzene and the like. The composition of the catalyst is preferably in the range of 0.1 to 5 gram atoms, particularly preferably in the range of 0.3 to 3 gram atoms of the organic iodide as the second component, as iodine atoms per 1 gram atom of palladium metal as the first component. It is.

The catalyst components used in the present invention, palladium metal and organic iodide, are preferably supported on an inert carrier commonly used for catalytic reactions. In this case, activated carbon is particularly desirable as the carrier. In addition, when preparing supported catalysts,
For example, it is convenient to prepare the desired supported palladium according to conventional methods and then add it to a solution of organic iodide in a carboxylic acid. In this case, it is also possible to substitute a commercially available palladium with a carrier.

Although the supported amount of each component of the catalyst can be selected arbitrarily, it is usually desirable that the palladium metal is 0.5 to 2 weight percent based on the carrier.

The carboxylic acid used in the present invention is not particularly limited, but aliphatic carboxylic acids having 2 to 5 carbon atoms are preferred, and acetic acid is particularly preferred.

The purity of oxygen used in the present invention is not particularly limited, and air or pure oxygen is used, but it is also possible to use these diluted with nitrogen or carbon dioxide.

There is no particular limit to the amount of oxygen used, as long as the composition of the mixed gas of 1,3-butadiene or carboxylic acid and oxygen is kept outside the explosive limit. In carrying out the present invention, either a gas phase reaction or a liquid phase reaction can be adopted as the reaction method.
A liquid phase reaction is preferred.

Furthermore, when carrying out the present invention, the reaction temperature is between 30 and 25
The number is preferably 0oo, particularly preferably 60 to 13,000.

Further, the present invention can be carried out under normal pressure or increased pressure,
In the case of pressurization, it is desirable to carry out under 150k9' (gauge pressure).

When carrying out the present invention, the amount of catalyst can be selected arbitrarily;
In the case of a liquid phase reaction, the amount of palladium metal per 1 reaction solution is preferably 0.5 to 100 hours, and in the case of a gas phase reaction, the space velocity is usually in the range of 100 to 50,000 hours. It is desirable to use a suitable amount of catalyst.

When carrying out the present invention in a liquid phase reaction, a solvent is not particularly required, but a solvent inert to the oxidation reaction of esters, saturated hydrocarbons, etc. may be used.

The present invention will be explained in more detail below using Examples and Comparative Examples.

Example 1 2 equipped with a flywheel, reflux condenser, gas inlet pipe and thermometer
2% manufactured by Engelhardt Co., Ltd. in a 00'40 flask
13.3 g of palladium on carbon (2.5 milligram atoms of palladium metal) and 100 g of acetic acid were added.

Then, 0.425 mmol (2.5 mmol) of inpopropyl iodide was added and the mixture was poured for 3 minutes. Thereafter, the temperature was raised to 100:00, and butadiene and molecular oxygen were each flowed through the gas introduction tube at a flow rate of 40 M/min. After 1 hour of reaction, the catalyst was separated from the furnace and the furnace liquid was analyzed by gas chromatography, and it was found that 1,4-diacetoxybutene-2 (1,4-DAB)
2.49 and 3,4-diacetoxybutene-1 (3
・41 DAB) 0.02 evening was generated.

1,4- in all acetoxybutenes (DAB) produced
DAB selectivity corresponds to 99.2%. Example 2 The same operation as in Example 1 was carried out, but with 0.85% isopropyl iodide.
0 mol (5 mmol) was used.

The results are shown in Table 1 together with the results of Examples 2 to 7 and Comparative Example 1. Example 3 The same operation as in Example 1 is carried out, but with 0.2 inpropyl iodide.
No. 13 (1.25 mmol) was used.

Example 4 The same operation as in Example 1 is carried out, but 0.9 n-butyl iodide is used instead of 0.425 isopropyl iodide.
(5 mmol) was used for 20 days.

Examples 5-7 The same operation as in Example 1 is carried out, but with 0.0% isopropyl iodide.
In Example 5, instead of 425 methylene iodide, 0.670
(2.5 mmol), and in Example 6 0.5 mmol of penzyl iodide.
In Example 7, iodoacetic acid 0.465 (2.5 mmol) was used.

Comparative Example 1 The same operation as in Example 1 was carried out, but isopropyl iodide was not used.

Table 1

Claims (1)

[Claims] 1. A catalyst comprising palladium metal and an organic iodide is used when producing 1,4-diacyloxybutene-2 by reacting 1,3-butadiene with a carboxylic acid and molecular oxygen. A method for producing 1,4-diacyloxybutene-2. 2. The method for producing 1,4-diacyloxybutene-2 according to claim 1, wherein the catalyst composition is 0.3 to 3 iodine atoms of the organic iodide per 1 gram atom of palladium metal. 3. A method for producing 1,4-diacyloxybutene-2 according to claim 1, in which the catalyst components are supported on activated carbon. 4. The method for producing 1,4-diacyloxybutene-2 according to claim 1, wherein acetic acid is used as the carboxylic acid. 5. The method for producing 1,4-diacyloxybutene-2 according to claim 1, wherein the reaction is carried out in a liquid phase. 6. The method for producing 1,4-diacyloxybutene-2 according to claim 1, wherein the reaction temperature is 60 to 130°C.