JPS6141902B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing 1,4-diacyloxybutene-2, and more 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. Relating to a method of manufacturing. 1,4-Diacyloxybutene-2 becomes 1,4-butanediol through hydrogenation and hydrolysis, and is an extremely important raw material industrially. 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 of producing a considerable amount of 3,4-diacyloxybutene-1, which has little industrial value, and therefore cannot be called an industrially advantageous production method. For example, JP-A-48-
According to Example 1 of Publication No. 72090 and Example 1 of Japanese Patent Application Laid-open No. 140406/1983, the production ratio of 1,4-diacetoxybutene-2 and 3,4-diacetoxybutene-1 is 86, respectively. :14 and 81:19. Therefore, in order to increase the yield of 1,4-diacyloxybutene-2, it is necessary to isomerize the by-produced 3,4-diacyloxybutene-1 to 1,4-diacyloxybutene-2. In fact, this isomerization method has also been proposed (for example, in Japanese Patent Application Laid-open No. 1973-
(See Publication No. 30616 and Japanese Unexamined Patent Application Publication No. 126611/1983). However, isomerization is extremely disadvantageous from an industrial perspective because it increases the number of steps, and even more disadvantageous is that 3,4-diacyloxybutene-1 is a type of vinyl compound, so polymerization reactions, etc. 1,4-diacyloxybutene-2
The isomerization yield is not satisfactory. The present inventors have made extensive studies to overcome these drawbacks, and have found that (i) palladium metal, and (ii) at least one member selected from iodic acid, alkali metal iodates, and ammonium iodate salts. The present invention was achieved by discovering an industrially advantageous method for producing 1,4-diacyloxybutene-2 by using a composite catalyst with iodic acid or iodate salt. That is, the present invention uses (i) palladium metal and (ii) at least one iodic acid or iodate salt selected from the group of iodic acid, alkali metal iodate, and iodine ammonium salt, as a catalyst, and palladium. metal 1
1, consisting of reacting 1,3-butadiene with a carboxylic acid and molecular oxygen using iodic acid or iodate in a ratio of 0.1 to 1.5 moles per gram atom;
A novel method for producing 4-diacyloxybutene-2 is provided. According to the method of the present invention, as shown in the examples,
The selectivity of 1,4-diacyloxybutene-2 in the produced diacyloxybutene is extremely high;
The amount of -diacyloxybutene-1 produced is extremely small, and it is substantially possible to produce only 1,4-diacyloxybutene-2. The first component of the catalyst used in the present invention is palladium metal, and the second component is iodic acid or an alkali metal iodate or an ammonium iodate salt. The alkali metal iodate used as the second component includes lithium iodate, sodium iodate,
Examples include potassium iodate, rubidium iodate, and cesium iodate. In addition, the second component ammonium iodate salt has the general formula R ₁ R ₂ R ₃ R ₄ NIO ₃ (where
R ₁ , R ₂ , R ₃ , and R ₄ each represent a hydrogen atom, an alkyl group, an aralkyl group, an allyl group, etc., and R ₁ and
R ₂ or R ₁ , R ₂ and R ₃ may form a continuous nitrogen-containing heterocycle. ). These ammonium iodate salts include, for example, ammonium iodate (NH ₄ IO ₃ ), triethylamine iodate, trimethylamine iodate, tetramethylammonium iodate, trimethylbenzylammonium iodate, pyridine iodate, piperazine iodate. Examples include acid salts. Generally, in oxidation reactions using catalysts containing palladium as a main component, efforts are made to increase the catalytic activity by adding metal halides, carboxylates, etc. as promoters. At this time, it is generally considered advisable to use metal halides, carboxylic acid salts, etc., which are co-catalysts, in excess of palladium in terms of molar ratio. However, the present inventors discovered that the composition of the catalyst consisting of palladium metal as the first component and iodic acid or alkali metal iodate or ammonium iodine acid salt as the second component is based on 1 gram atom of palladium metal. On the other hand, the iodic acid or iodate salt is 0.1 to 1.5
It has been found that the selectivity of 1,4-diacyloxybutene-2 within a very limited molar range is improved, and the catalytic activity is also improved. This fact is not recognized when a halogen acid other than iodic acid or an alkali metal salt or ammonium salt of a halogen acid other than iodic acid is used as the second component of the catalyst; This is a completely unexpected effect that is exhibited only by acids, alkali metal iodates, or ammonium iodates, and is a phenomenon that cannot be imagined from the common sense of conventional palladium catalysts. Furthermore, in order to achieve the object of the present invention, the favorable composition ratio of the catalyst components palladium metal and iodic acid, alkali metal iodate, or ammonium iodate is extremely limited.
It is presumed that the catalyst used in the present invention differs from the conventional concept of a main catalyst and a co-catalyst, and each component of the catalyst forms a composite compound such as a complex compound, and this composite compound exhibits a remarkable catalytic action. The catalyst components used in the present invention, palladium metal and kazoic acid or alkali metal iodate or ammonium iodate, are supported on a carrier used in ordinary catalytic reactions, such as activated carbon, silica gel, alumina, etc. is preferable,
Particularly preferred carrier is activated carbon. The supported catalyst used in the present invention can be prepared by a conventional general method. To give an example, firstly, a desired content of supported palladium is prepared according to a conventional method, and then this is mixed with iodic acid or It is convenient to prepare it by adding it to an aqueous solution of an alkali metal iodate or the like. At this time, it is also possible to substitute a commercially available palladium with a carrier. The amount supported on each component of the catalyst can be selected arbitrarily, but usually the amount of palladium metal supported on the carrier is 0.05
~20 weight percent is preferred. The carboxylic acid used in the reaction of the present invention is not particularly limited, but aliprotected carboxylic acids having 2 to 5 carbon atoms are preferred, and acetic acid is particularly preferred. There is no particular restriction on the purity of oxygen used in the reaction of the present invention, and usually 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, and from the viewpoint of operational safety, it is sufficient to keep the mixed gas composition of 1,3-butadiene or carboxylic acid and oxygen outside the explosive limit. In carrying out the method of the present invention, either a gas phase reaction or a liquid phase reaction can be employed as the reaction method. In addition, the reaction of the present invention can be carried out either under normal pressure or under increased pressure, and in the case of increased pressure, the reaction rate is 150 kg/cm ²
(gauge pressure) or less. Furthermore, the reaction temperature when carrying out the reaction of the present invention is preferably 50 to 250°C, particularly preferably 60 to 250°C.
The temperature is 130℃. The amount of catalyst when carrying out the reaction of the present invention can be arbitrarily selected, but in the case of a liquid phase reaction, it is desirable that the amount of palladium metal per reaction solution 1 is 0.5 to 100 g, and in the case of a gas phase reaction Generally, it is desirable to use an amount of catalyst such that the space velocity is in the range of 100 to 50,000 hr ^-1 . When carrying out the reaction of the present invention in a liquid phase, a solution is not particularly required, but a solvent inert to the oxidation reaction may be used. Examples of solvents inert to the oxidation reaction include 1,4-diaxyloxybutene-2- such as 1,4-diacetoxybutene-2; ethylene glycol such as ethylene glycol diacetate; Diester;
Examples include esters of ethanol such as ethyl acetate. Examples of the present invention will be described below along with comparative examples. Example 1 2.5 mmol of potassium iodate was dissolved in 100 ml of water, and a 2% palladium carbon catalyst manufactured by Nippon Engelhard Co., Ltd. was added as palladium metal to this aqueous solution.
2.5 milligram atom equivalents were added with stirring, then after evaporating the water to dryness on a steam bath,
It was vacuum dried at 120°C for 2 hours. The thus obtained catalyst was placed in a 200 ml four-neck flask equipped with a stirrer, a thermometer, a gas inlet tube, and a reflux condenser together with 100 ml of acetic acid and heated to 100°C.
It was passed at a flow rate of min. After reacting for 1 hour, the catalyst was removed and the liquid was analyzed by gas chromatography. . The results are shown in Table 1 along with the results of Examples 2 to 10 and Comparative Examples 1 to 5.
Shown below. Examples 2 to 5 The amount of potassium iodate used was 0.75 in Example 2.
mmol, 1.25 mmol in Example 3, Example 4
The reaction of Example 1 was repeated except that the amount was 2 mmol in Example 5 and 3 mmol in Example 5. The results are in the table.
Shown in 1. Examples 6 and 7 The reaction of Example 1 was repeated except that in Example 6 the reaction temperature was 75°C and in Example 7 it was 110°C. The results are shown in Table-1. Example 8 2.5 mmol of iodic acid instead of 2.5 mmol of potassium iodate
The reaction of Example 1 was repeated except that mmol was used. The results are shown in Table 1. Examples 9, 10, 11 and 12 Instead of 2.5 mmol of potassium iodate, lithium iodate was used in Example 9, rubidium iodate was used in Example 10, ammonium iodate was used in Example 11, and iodine was used in Example 12. The reaction of Example 1 was repeated, except that 2.5 mmol of tetraethylammonium acid was used in each case. The results are shown in Table-1. Comparative Example 1 The reaction of Example 1 was repeated except that the amount of potassium iodate was 5 mmol. The results are shown in Table-1. Comparative Examples 2, 3 and 4 Comparative Example 2 instead of 2.5 mmol of potassium iodate
The reaction of Example 1 was repeated except that 2.5 mmol of potassium chlorate was used in Comparative Example 3, 2.5 mmol of potassium bromate was used in Comparative Example 4, and 2.5 mmol of bromate was used in Comparative Example 4. The results are shown in Table-1. Comparative Example 5 Into the same four-necked flask as used in Example 1, 2% palladium carbon catalyst made by Nippon Engelhard Co., Ltd. equivalent to 2.5 milligram atoms as palladium metal and 100 ml of acetic acid were charged, and then 100 ml of acetic acid was charged. The same oxidation reaction operation as in 1 was performed. The results are in the table.
Shown in 1.

[Table] Example 13 2.5 mmol of palladium chloride was added to a solution of 0.5 ml of concentrated hydrochloric acid and 100 ml of water, and dissolved by heating to a temperature of 40 to 60° C. above the water solution. To this solution, 13.0 g of coconut husk charcoal (30 to 50 mesh) was added and left to stand for 2 hours, and then the water was evaporated to dryness. Next, the activated carbon that had adsorbed palladium chloride was packed in a glass reaction tube, dried at 150°C with nitrogen gas flowing at a flow rate of 200ml/min for 2 hours, then heated to 300°C, and heated with 200ml of hydrogen gas. After flowing at a flow rate of /min for 3 hours, the mixture was thoroughly washed with water and vacuum dried at 120°C. The supported palladium prepared in this way was mixed with potassium iodate.
It was added to 100 ml of an aqueous solution containing 2.50 mmol with stirring, and the water was evaporated to dryness, followed by vacuum drying at 120° C. for 2 hours. The same reaction as in Example 1 was carried out using the obtained catalyst. When the reaction solution was measured by gas chromatography, 1.429g of diacetoxybutene was produced, of which 1.4-diacetoxybutene-2 was
98.9%, 3,4-diacetoxybutene-1 is 1.1
It was %.

Claims (1)

[Claims] 1 1,4-diacyloxybutene is produced by reacting 1,3-butadiene with a carboxylic acid and molecular oxygen.
2, palladium metal is used as a catalyst, and (ii) at least one iodic acid or iodate selected from the group of iodic acid, alkali metal iodate and ammonium iodate salt. 1. A method for producing 1,4-diacyloxybutene-2, characterized in that iodic acid or iodate salt is used in a ratio of 0.1 to 1.5 mol per gram atom of metal. 2. The production method according to claim 1, wherein the catalyst composition is 0.3 to 1.25 moles of iodic acid, alkali metal iodate, or ammonium iodate per gram atom of palladium metal. 3. The manufacturing method according to claim 1 or 2, wherein the catalyst component is supported on activated carbon. 4. The manufacturing method according to any one of claims 1 to 3, wherein the carboxylic acid is acetic acid. 5. The manufacturing method according to any one of claims 1 to 4, wherein the reaction is carried out in a liquid phase. 6. The manufacturing method according to any one of claims 1 to 5, wherein the reaction temperature of the reaction is 60 to 130°C.