JPH0625082A - Production of unsaturated carboxylic acid ester - Google Patents

Abstract

PURPOSE:To produce an unsaturated carboxylic acid ester in a high-space-time yield by a new catalytic preparation method. CONSTITUTION:An olefin is made to react with oxygen and acetic acid in a vapor phase in the presence of a palladium catalyst prepared by subjecting a palladium ammonium complex to ion exchange with the surface hydroxyl group of a catalyst support, then subjecting the ion-exchanged complex to reduction treatment and further carrying an alkali metal acetic acid salt on a catalyst support to produce the objective unsaturated carboxylic acid ester.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an unsaturated carboxylic acid ester by reacting an olefin, oxygen and acetic acid in a gas phase.

[0002]

2. Description of the Related Art A method for obtaining an unsaturated carboxylic acid ester by reacting an olefin, oxygen and acetic acid in a gas phase in the presence of a palladium catalyst is known. These are mainly palladium precursors such as PdCl ₂ and Na ₂ PdCl ₄ and, if necessary, as promoters, gold, copper, lead, iron, vanadium, chromium, molybdenum, bismuth, manganese,
At least one metal salt of antimony, tungsten, thallium, ruthenium, etc. is impregnated into a carrier such as silica, alumina, silica-alumina, titanium oxide, etc., and the catalyst is reduced with hydrogen, hydrazine, etc. A catalyst supporting an alkali metal acetate is used.

[0003]

When an unsaturated carboxylic acid ester is produced by using a palladium catalyst, the space-time yield is increased by increasing the reaction temperature, but at the same time, the by-product carbon dioxide is also increased. Therefore, the selectivity of unsaturated carboxylic acid ester is lowered. Therefore, in order to produce an unsaturated carboxylic acid ester with high selectivity, a catalyst with high activity is required even at low temperature, but sufficient activity cannot be obtained by known methods.

Therefore, an object of the present invention is to provide a method for producing an unsaturated carboxylic acid ester in a high space-time yield by a novel catalyst preparation method.

[0005]

Means for Solving the Problems As a result of extensive studies to achieve the above object, in a method for producing an unsaturated carboxylic acid ester by reacting olefin, oxygen and acetic acid in a gas phase, a palladium ammonia complex is used as a catalyst carrier. After the ion-exchange with the surface hydroxyl groups of, the reduction treatment, and by further supporting the alkali metal acetate on the catalyst carrier, it is possible to prepare a highly active catalyst, and when preparing the palladium catalyst, the reduction treatment is performed using an aqueous hydrazine solution. In the case of carrying out, it was found that the space-time yield is further improved by performing a reduction treatment after firing with a gas containing oxygen, and the present invention has been completed.

As the carrier, silica, alumina, silica-alumina, titania or the like having a hydroxyl group having ion exchange ability on the surface of the carrier can be used, and silica having a large number of hydroxyl groups on the surface of the carrier is particularly preferable. Is.

The palladium-ammonia complex to be used is not particularly limited as long as it is ion-exchanged with the surface hydroxyl groups of the carrier, but tetraamminepalladium chloride {Pd (NH ₃ ) ₄ Cl ₂ } or tetraamminepalladium ion in an aqueous ammonia solution is used. {Pd (NH ₃ ) ₄
Palladium chloride or palladium acetate which produces ²⁺ } can be used.

The silica carrier is immersed in an aqueous solution containing a palladium-ammonia complex or an aqueous ammonia solution to ion-exchange the surface hydroxyl groups of the silica carrier with the palladium-ammonia complex ion. The loading ratio of palladium is preferably in the range of 0.1 to 10.0% by weight relative to silica, and 0.5 to
The range of 5.0% by weight is more preferable.

After the palladium-ammonia complex is ion-exchanged with the surface hydroxyl groups of the catalyst carrier, it may be burned with a gas containing oxygen, if necessary, or may be subjected to the reduction treatment as it is. However, when the reduction treatment is performed using an aqueous hydrazine solution, it is more preferable to perform the reduction treatment after firing with a gas containing oxygen. Air can be used as the gas containing oxygen. If the firing temperature is too high, the activity may decrease, so 600 ° C. or lower is desirable, and about 300 to 500 ° C. is particularly preferable. The firing time at this time is usually 1 hour or more.

The catalyst after calcination is converted to palladium metal by reduction treatment. The reducing agent is not particularly limited, but hydrogen or a hydrazine aqueous solution can be used.

If necessary, the catalyst may be gold as a co-catalyst,
Copper, lead, iron, vanadium, chromium, molybdenum, bismuth, manganese, antimony, tungsten, thallium,
At least one metal or metal salt selected from ruthenium and the like may be supported.

Further, the alkali metal acetate is supported on the catalyst on which the palladium metal and the promoter are supported. As the alkali metal acetate, potassium acetate is preferred. The amount of supported alkali metal acetate is 1 to silica.
A range of 15% by weight, particularly a range of 5-10% by weight is desirable.

The unsaturated carboxylic acid ester according to the present invention is produced by charging the above-mentioned specific catalyst into a suitable reactor. When an unsaturated carboxylic acid ester is produced by reacting an olefin, oxygen and acetic acid in the present invention, the reaction temperature is 100 to 200 ° C., preferably 150.
It is carried out at a temperature of ˜180 ° C. and atmospheric pressure to 30 atm, preferably atmospheric pressure to 10 atm.

In the present invention, the gas supplied to the reaction system is a gas consisting of olefin, oxygen and acetic acid, and can be diluted with an inert gas such as nitrogen if necessary.
The olefin content is 10 to 60% by volume, preferably 30 to 50% by volume, based on the total amount of the supplied gas.
Oxygen is in an amount of 3 to 15% by volume, preferably 5 to 10% by volume, and acetic acid is 5 to 20% by volume, preferably 6 to 10%.
Each of them is supplied to the reaction system in an amount of volume%.

The alkali metal acetate supported on the catalyst may be gradually released during the reaction and flow out of the reaction system. Therefore, in order to maintain the supported amount of the alkali metal acetate supported on the catalyst, the alkali metal acetate may be added to the reaction system as an aqueous solution or an acetic acid solution by adding it to the reaction system.

[0016]

The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

Example 1 Tetraamminepalladium chloride {Pd (NH ₃ ) ₄ C
l ₂ } 0.729 g containing 1N ammonia water 100
100 ml of a spherical silica carrier was immersed in ml to absorb water sufficiently. Next, after thoroughly removing ammonia by washing, 110 ° C
And dried for 3 hours. The palladium ion-exchanged silica carrier was air-calcined at 400 ° C. for 5 hours and then reduced with hydrogen at 300 ° C. for 5 hours to carry palladium. Further, after pouring into 50 ml of an aqueous solution containing 3.0 g of potassium acetate, 1
A catalyst supporting palladium and potassium acetate was prepared by drying at 10 ° C. for 3 hours.

10 ml of the obtained catalyst was filled in a stainless steel reaction tube having an inner diameter of 16 mm, and propylene 50% and oxygen 9
%, Acetic acid 7%, nitrogen 33% mixed gas 13.6Nl /
The reaction was carried out under the conditions of a reaction temperature of 150 ° C. and a pressure of 5 atm (gauge pressure) by supplying at a rate of Hr. The results are shown in Table 1.

Example 2 In Example 1, 1 containing 0.634 g of palladium acetate {Pd (OCOCH ₃ ) ₂ } in place of tetraammine palladium chloride {Pd (NH ₃ ) ₄ Cl ₂ }.
A catalyst was prepared in the same manner as in Example 1 except that an aqueous solution of N ammonia was used.

10 ml of the obtained catalyst was reacted under the same conditions as in Example 1. The results are shown in Table 1.

Example 3 In the preparation of the catalyst in Example 1, an aqueous solution 80 containing 3.0 g of hydrazine instead of hydrogen reduction after calcination was used.
The same operation was carried out except that the palladium catalyst was obtained by reduction with ml. The results are shown in Table 1.

Example 4 In the preparation of the catalyst in Example 2, an aqueous solution 80 containing 3.0 g of hydrazine instead of hydrogen reduction after calcination was used.
The same operation was carried out except that the palladium catalyst was obtained by reduction with ml. The results are shown in Table 1.

Comparative Example 1 Sodium chloropalladate (Na ₂ PdCl ₄ ) 0.
To 40 ml of an aqueous solution containing 987 g, 100 ml of a spherical silica carrier was added to sufficiently absorb it, followed by drying under reduced pressure. Next, after air-baking this at 500 ° C. for 5 hours, it is further added
It was reduced with hydrogen at 0 ° C. for 5 hours to support palladium. Further, the mixture was poured into 50 ml of an aqueous solution containing 3.0 g of potassium acetate and dried at 110 ° C. for 3 hours to prepare a catalyst supporting palladium and potassium acetate.

10 ml of the obtained catalyst was reacted under the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 2 A spherical silica carrier 100 was added to 50 ml of a 2.4N hydrochloric acid aqueous solution containing 0.501 g of palladium chloride (PdCl ₂ ).
After adding ml, the mixture was sufficiently absorbed and dried under reduced pressure. Next, this was air-baked at 500 ° C. for 5 hours, and further reduced with hydrogen at 300 ° C. for 5 hours to carry palladium. Further, the mixture was poured into 50 ml of an aqueous solution containing 3.0 g of potassium acetate and dried at 110 ° C. for 3 hours to prepare a catalyst supporting palladium and potassium acetate.

10 ml of the obtained catalyst was reacted under the same conditions as in Example 1. The results are shown in Table 1.

[0027]

[Table 1]

[0028]

EFFECTS OF THE INVENTION By using a palladium catalyst prepared by subjecting a palladium-ammonia complex to ion exchange with a hydroxyl group on the surface of a catalyst carrier and then reducing it, and then carrying an alkali metal acetate on the catalyst carrier, a high space-time yield can be obtained. The unsaturated carboxylic acid ester can be produced at a rate.

Further, in the preparation of the catalyst, the catalyst obtained by firing with a gas containing oxygen before the reduction treatment and then reduction treatment with an aqueous hydrazine solution can be used to further improve the space-time yield. It will be extremely useful.

Claims (2)

[Claims] 1. An olefin in the presence of a palladium catalyst, which is prepared by ion-exchange of a palladium ammonia complex with a surface hydroxyl group of a catalyst carrier, followed by reduction treatment, and further carrying an alkali metal acetate on the catalyst carrier. A method for producing an unsaturated carboxylic acid ester by reacting oxygen and acetic acid in a gas phase. 2. A method in which a palladium ammonia complex is ion-exchanged with a surface hydroxyl group of a catalyst carrier, calcined with a gas containing oxygen, reduced with an aqueous solution of hydrazine, and further an alkali metal acetate is supported on the catalyst carrier. A method for producing an unsaturated carboxylic acid ester by reacting an olefin, oxygen and acetic acid in a gas phase in the presence of a palladium catalyst.