JPS6147819B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved process for producing vinyl paratertiary butyl benzoate.

Conventionally, a method is known in which a carboxylic acid with a relatively large number of carbon atoms and a vinyl ester are transesterified in the presence of a mercury salt catalyst such as mercury sulfate or mercury acetate to produce a carboxylic acid vinyl ester different from the raw material vinyl ester. It is being

However, this method requires the use of harmful mercury compounds and is not preferred in practice.

Alternatively, a method using palladium acetate in combination with a chelate forming agent such as pipyridyl or 1,10-phenatroline as a catalyst [Tetrahedron Vol. 28, 1972, p. 233]
Although this method is known, it is necessary to separately synthesize a chelate compound in advance using a chelate forming agent such as the one described above, and since such chelate forming agents are expensive, the product The disadvantage is that the cost is high.

On the other hand, when palladium acetate is used alone, there is a problem that palladium is reduced and the reaction stops (Can. J. Chsm. Vol. 53, 1975,
(see page 223).

Although this reduced palladium can be recovered and regenerated relatively easily, it cannot be denied that these steps are extremely disadvantageous from an industrial standpoint in terms of operation and cost. Moreover, unreduced palladium also exists in dissolved form in the liquid, so its recovery is also very disadvantageous from the operational and cost standpoints.

As a result of studies to solve the above-mentioned disadvantages, the present inventors have discovered that the desired vinyl paratertiary butylbenzoate can be advantageously produced by reacting in the presence of the solid catalyst and co-catalyst described below. I found out.

That is, the present invention provides a solid catalyst comprising paratertiary butylbenzoic acid and vinyl acetate, palladium metal and/or a palladium compound adsorbed and supported on the surface of a carrier, and a copper compound containing at least one type of halide and an alkali metal. The present invention relates to a method for producing vinyl paratertiary butylbenzoate, which is characterized in that the reaction is carried out in the presence of a co-catalyst consisting of a compound of the present invention.

The present invention will be explained in detail below.

The solid catalyst used as the main catalyst in the method of the present invention is made by adsorbing and supporting palladium metal or a palladium compound on the surface of a carrier. Examples of palladium compounds that can be used here include palladium acetate and propionic acid. Examples include palladium carboxylates such as palladium, inorganic palladium salts such as palladium chloride, palladium bromide, and palladium nitrate, and palladium complex compounds such as dichlorobis(benzonitrile)palladium.

Supporting palladium metal is prepared by supporting the above-described palladium compound on a carrier and then subjecting it to a reduction treatment. A well-known method can be used for this reduction treatment, such as immersing a carrier supporting the palladium compound in an aqueous solution of potassium hydroxide and formalin.

Examples of carriers for adsorbing and supporting these palladium metals or palladium compounds include activated carbon, silica, and silica alumina, with activated carbon being particularly effective.

When adsorbing and supporting the palladium compound on a carrier, it is best to use a normal liquid phase support method. Specifically, the palladium compound is dissolved in a suitable solvent such as hydrochloric acid, acetic acid, benzene, etc. Afterwards, the carrier is immersed in a solvent solution of this palladium compound, and then the carrier is taken out from the solution,
Just dry it.

Furthermore, the amount of palladium metal or palladium compound to be adsorbed onto the surface of the carrier is preferably 0.1 to 1 part by weight (as palladium) per 100 parts by weight of the carrier, but this is not particularly limited and may be used as needed. There is no problem in increasing or decreasing the supported amount.

The co-catalyst used in combination with the above solid catalyst is an alkali metal compound and a copper compound, and it is necessary to use the alkali metal compound and the copper compound at the same time, but at least one of them is a halide. Must. Suitable alkali metal compounds include alkali metal salts or hydroxides, including sodium carbonate, potassium acetate, sodium hydroxide, potassium hydroxide, sodium chloride, sodium bromide, potassium iodide, and potassium bromide. Examples of copper compounds include copper acetate, copper nitrate, copper oxide, copper chloride,
Examples include copper bromide. Combinations of the above alkali metal compounds and copper compounds include sodium chloride, sodium bromide, potassium iodide, potassium bromide,
It must contain at least one halide selected from copper chloride, copper bromide, etc.

In the method of the present invention, it is necessary to oxidize the reduced copper compound by contacting the liquid during or after the transesterification reaction with oxygen. In other words, rather than using an inert gas such as nitrogen in the surrounding air, oxygen or an oxygen-containing gas,
Even better results can be obtained by using air, for example. In this case, the pressure of the surrounding air may be set higher than atmospheric pressure if necessary.

In carrying out the ester (vinyl) exchange reaction, the mixing molar ratio of paratertiary butylbenzoic acid and vinyl acetate is usually preferably in the range of 1:3 to 1:15.

In addition, the amount of the catalyst used is 0.0001 to 0.001 as the amount of the solid catalyst as the main catalyst and the amount of the palladium compound per 1 mole of paratertiary butylbenzoic acid.
mole, 0.005 to 0.05 mole of alkali metal compound,
Halides and copper compounds each from 0.001 to 0.01
Preferably, it is expressed in moles.

Note that it is optional to use an alkali metal or copper halide in combination with a compound other than the respective halide, and since the solubility of the alkali metal compound in the reaction mixture is not very high, this compound may be used in combination. Even if it is used beyond the above-mentioned range, no particularly significant effect will generally be obtained.

The reaction temperature is generally in the range from room temperature to around 70°C, but is not limited thereto.

Next, as a specific reaction method, a method in which a mixture of paratertiary butylbenzoic acid, vinyl acetate, and a cocatalyst is reacted batchwise with a solid catalyst suspended or fixed in a reactor; There are methods such as a combination of this batch method and a flow method using this solid catalyst as a fixed bed. In carrying out this reaction, a solvent may be used if necessary, and examples of the solvent include tetrahydrofuran and acetonitrile.

According to the method of the present invention, palladium in the solid catalyst remains active throughout the reaction process without being reduced or deactivated, and this catalyst can be reused. Alkali metal compounds can also be reused. Further, the carboxylic acid by-produced by this transesterification reaction can be easily recovered by a conventional method.

The method of the present invention is characterized by the above-mentioned catalyst system, that is, mainly consisting of a solid catalyst formed by adsorbing and supporting palladium metal or a palladium compound on the surface of a carrier, and a combination of an alkali metal compound containing at least one type of halide and a copper compound. The objective vinyl paratertiary butyl benzoate can be obtained in high yield without any unfavorable side reactions, and in this case no good result can be obtained even if any one of the above combinations is missing.

Hereinafter, a detailed explanation will be given with reference to examples.

Example 450 ml of water was added to 15 ml of hydrobromic acid in which 1.59 g of palladium chloride was dissolved, and 300 ml of granular activated carbon of 8 to 32 meshes was immersed in the solution, followed by stirring at room temperature for about 1 hour. After that, the activated carbon is filtered out,
After thorough washing with water, this was dried at about 70°C to prepare a catalyst.

17 ml of the catalyst obtained in this way was mixed with a mixed solution consisting of 178 g of paratertiary butylbenzoic acid, 688 g of vinyl acetate, 3.92 g of potassium acetate, and 0.67 g of cupric bromide in a stirrer, a thermometer, and a cooling tube. Pour into a flask with an internal volume of 1, and bring the internal temperature to 65°C while stirring so that the liquid surface comes into contact with the air.
When the reaction was kept at ℃ for about 10 hours, 98
g, and 42 g of by-product acetic acid were recovered.

After distilling this reaction solution under reduced pressure, 85.5 g of paratertiary butylbenzoic acid and 688 g of vinyl acetate were added to the remaining 110 g of the reactor, and the reaction was carried out in the same manner as above by reusing the previous catalyst. Vinyl butyl benzoate 100g, by-product acetic acid
42g was recovered.

The above catalyst reuse reaction was repeated five times, but the activity of the catalyst did not deteriorate.

Comparative Example 1 When the reaction was carried out in the same manner as in the above Example except that potassium acetate was not used, the reaction rate was significantly reduced and the recovered vinyl paratatium butylbenzoate and by-product acetic acid were 31g and 31g, respectively. It was only 10g.

Comparative Example 2 When the reaction was carried out in the same manner as in the above Example except that cupric bromide was not used, the catalytic activity was reduced by half after the third repeated reaction (catalyst reuse).

Claims (1)

[Scope of Claims] 1 Paratertiary butylbenzoic acid and vinyl acetate are combined with a solid catalyst formed by adsorbing and supporting palladium metal and/or a palladium compound on the surface of a carrier, and a copper compound containing at least one type of halide. 1. A method for producing vinyl paratertiary butylbenzoate, which comprises reacting it in the presence of a cocatalyst comprising an alkali metal compound. 2. The method according to claim 1, wherein in the reaction, vinyl acetate is reacted at a ratio of 3 to 15 moles per mole of paratertiary butylbenzoic acid. 3. The method according to claim 1, wherein the halogen of the halide is bromine. 4. The method according to claim 1, wherein the alkali metal of the alkali metal compound is potassium. 5. The method according to claim 1, wherein the carrier is activated carbon. 6 The usage ratio of the halide, copper compound and alkali metal compound is 0.001 to 0.01, respectively, per 1 mole of paraterasiabutylbenzoic acid.
The method according to claim 1, characterized in that the amount is in the range of 0.001 to 0.01 and 0.005 to 0.05 mol.