JPH0633297B2 - Method for producing palladium chelate complex - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for producing a palladium chelate complex.

BACKGROUND OF THE INVENTION When a palladium chelate complex formed from a palladium salt and a basic bidentate ligand is subjected to oxidative coupling (duplexing) of o-phthalic acid diester to produce biphenyltetracarboxylic acid tetraester. It has been proposed to use it as a catalyst (Japanese Patent Publication No. 60-33379, Japanese Patent Publication No. 60-51150 and Japanese Patent Publication No. 60-51).
51151).

Japanese Patent Publication No. 60-33379 discloses that an organic palladium salt can be used as a palladium salt, and describes a method for producing a dicarboxylatopalladium chelate complex using a palladium salt of an aliphatic carboxylic acid. Has been done. The dicarboxylato palladium chelate complex can be generally synthesized by reacting the corresponding palladium salt of an aliphatic carboxylic acid with a basic bidentate ligand, and its production method is described in JP-B-60-3.
In addition to the method described in Japanese Patent No. 3379, many reports have been made.

For example, it is known that a diacetato palladium chelate complex can be synthesized by reacting palladium acetate with a basic bidentate ligand (JEMcKeon, P.Fitto
n, Tetrahedron, 28 , 233 (1972), TAStephenson, SMMore
house, ARPowell, JPHeffer, G, Willkinson, J.Chem.So
c., 3632 (1965), A.Shiotani, M.Yoshikiyo, H.Itatani, JM
olecular Catalysis, 18 , 23 (1981)).

On the other hand, in JP-A-60-51151, by using an inorganic acid palladium salt as a palladium salt, particularly palladium nitrate, a dinitratopalladium chelate complex excellent in thermal stability is obtained, and the complex is used. By doing so, the reaction yield of the dimer is improved, and 3,3 ′, 4,4′- is improved as compared with the case where a dicarboxylatopalladium chelate complex is used in the above oxidative coupling reaction.
Biphenyl tetracarboxylic acid tetraester (s-BP
It is described that TT) can be selectively synthesized.

The method for producing the dinitratopalladium chelate complex described in JP-A-60-51151 is a method of reacting an approximately equimolar amount of a basic bidentate ligand with palladium nitrate. To obtain a dinitratopalladium chelate complex represented by the general formula [Ia]: L · Pd (NO ₃ ) ₂ ... [Ia] (where L represents a basic bidentate ligand). However, when the basic bidentate ligand is used in excess with respect to palladium nitrate in the above method, the general formula [Ib]: L ₂ .Pd (NO ₃ ) ₂ ... [Ib] (where L is , Which represents a basic bidentate ligand), forming a dinitratopalladium chelate complex.

When the present inventor examined the catalytic action of each of the above organic or inorganic palladium chelate complexes, it was found that the dinitratopalladium bis chelate complex is a reaction that oxidatively couples o-phthalic acid diesters to produce biphenylcarboxylic acid tetraesters. In comparison with the dinitratopalladium monochelate complex, the induction period (time required after the start of the reaction until the reaction rate becomes sufficiently high)
Turned out to be long. Further, it was found that the dicarboxylatopalladium chelate complex has an advantage that the induction period is shorter than that of each dinitratopalladium chelate complex.

OBJECT OF THE INVENTION An object of the present invention is to provide a method for converting a dinitratopalladium chelate complex into a dicarboxylatopalladium chelate complex.

[Summary of the Invention] As a result of earnest research on a technique for exchanging an anion portion of a palladium chelate complex, the present inventor has found that dinitratopalladium chelate complex is reacted with an aliphatic carboxylic acid in the presence of an alkali to dicarboxylatopalladium. They have found that they can be converted into chelate complexes and completed the present invention.

That is, the present invention provides the compound of the general formula [I]: L _x Pd (NO ₃ ) ₂ ... [I] (wherein L represents a basic bidentate ligand, and x is 1 or 2). The dinitratopalladium chelate complex represented by RCOOH is reacted with an aliphatic carboxylic acid represented by RCOOH in the presence of an alkali to give a compound represented by the general formula [II]: L · Pd (RCOO) ₂ ... [II] (however, L is a basic bidentate ligand, and R is an alkyl group), and a dicarboxylatopalladium chelate complex is produced.

DETAILED DESCRIPTION OF THE INVENTION All of the dinitratopalladium monochelate complex, the dinitratopalladium bis chelate complex and the dicarboxylatopalladium chelate complex can be used as catalysts for oxidative coupling (dimerization) reaction of o-phthalic acid diester. It has been known.

However, the above three types of palladium chelate complexes are
It was found that the oxidative coupling reaction had different induction periods. Since the above-mentioned oxidative coupling reaction is generally carried out at a high temperature, a shorter induction period is advantageous for carrying out it industrially.

The induction period of each of the above palladium chelate complexes tends to be as shown in, for example, Tables 1 and 2 below and FIGS. 1 and 2 attached hereto.

Table 1 below shows 1,1 as a palladium chelate complex.
0-phenanthroline dinitratopalladium or 1,
Using 10-phenanthroline diacetatopalladium, 0.4 mmol of palladium chelate complex and 0.12 mmol of copper acetate-hydrate as a catalyst, air was passed at 300 m / min at 200 ° C. with stirring at 500 rpm. The reaction results when 119 g of o-dimethyl phthalate (hereinafter abbreviated as DMP) are oxidatively coupled are shown. Further, FIG. 1 shows that 3,3 ′,
It is a figure which shows the comparison of the time-dependent change of the yield of 4,4'- biphenyl tetracarboxylic acid tetramethyl. ○ when 1,10-phenanthroline dinitratopalladium is used
The mark shows the case where 1,10-phenanthroline diacetatopalladium was used, and each mark shows with Δ. As is clear from FIG. 1, the diacetato palladium chelate complex is
The induction period is shorter than that of the dinitratopalladium monochelate complex, and the induction period does not substantially exist. Therefore, it can be advantageously used by selecting the use conditions.

Table 1 below shows 1,1 as a palladium chelate complex.
0-phenanthroline dinitratopalladium (monochelate complex) or bis (1,10-phenanthroline)
Using dinitratopalladium (bis chelate complex),
DMP under the same conditions as above except that the temperature was 220 ° C.
The reaction results when oxidatively coupling is shown. The second
The figure is a diagram showing a comparison of changes over time in the yield of 3,3 ', 4,4'-biphenyltetracarboxylic acid tetramethyl in the above reaction. When 1,10-phenanthroline dinitratopalladium is used, it is marked with a circle, and bis (1,
The case where 10-phenanthroline) dinitratopalladium is used is shown by a cross mark. From FIG. 2, when the dinitratopalladium bis chelate complex is used as the catalyst for the above oxidative coupling reaction, the induction period is longer than that in the case where the dinitratopalladium monochelate complex is used, and the reaction with the same yield is obtained. It is clear that it takes more than twice as long to obtain the product.

It is clear from the above Tables 1 and 2 and the attached FIGS. 1 and 2 that each dinitratopalladium bis chelate complex is disadvantageous as compared with the dicarboxylatopalladium chelate complex. The development of a technique for converting a dinitratopalladium chelate complex into a dicarboxylatopalladium chelate complex having a short induction period is desired.

The present invention is represented by the general formula [I]: L _x Pd (NO ₃ ) ₂ ... [I] (wherein L represents a basic bidentate ligand and x is 1 or 2). The dinitratopalladium chelate complex represented by RCOOH is reacted with an aliphatic carboxylic acid represented by RCOOH in the presence of an alkali to give a compound represented by the general formula [II]: L · Pd (RCOO) ₂ [II] (where L is A basic bidentate ligand, wherein R represents an alkyl group), is formed to form a dicarboxylatopalladium chelate complex.

Next, the method of the present invention will be described in detail.

The above-mentioned dinitratopalladium chelate complex may be a dinitratopalladium monochelate complex or a dinitratopalladium bis chelate complex.

The basic bidentate ligand is preferably 1,10-phenanthroline or 2,2'-bipyridine.

The above reaction is preferably carried out in a state in which the dinitratopalladium chelate complex is dissolved in the aliphatic carboxylic acid corresponding to the target dicarboxylatopalladium chelate complex. Examples of the aliphatic carboxylic acid include lower aliphatic carboxylic acids having 1 to 5 carbon atoms which are liquid at room temperature, such as acetic acid, propionic acid and butyric acid, and acetic acid is preferable. The amount of the aliphatic carboxylic acid used is not particularly limited, but it is sufficient if the amount of the dinitratopalladium chelate complex is dissolved, and is usually 100 to 2000 m, preferably 200 to 700 m per 10 g of the complex.
Is.

In the method of the present invention, it is necessary to react the dinitratopalladium chelate complex with an aliphatic carboxylic acid in the presence of an alkali. When no alkali is present, the nitrato group of the dinitratopalladium chelate complex is not replaced by the carboxylato group, which is not preferable. Examples of the alkali include hydroxides, carbonates, bicarbonates and carboxylates of alkali metals or alkaline earth metals. The amount of the alkali used is usually 1 to 10 mol, preferably 2 to 5 mol, per mol of the dinitratopalladium chelate complex. When adding the alkali to the aliphatic carboxylic acid solution of the above-mentioned dinitratopalladium chelate complex, the alkali may be added in a state of being dissolved in a solvent soluble in the aliphatic carboxylic acid such as ethanol.

The reaction is preferably carried out in the temperature range of 20 to 250 ° C., more preferably refluxing the aliphatic carboxylic acid. The reaction time is generally 10 minutes to 10 hours, preferably 30 minutes to 2 hours.

By the above-mentioned treatment, the nitrato group of the dinitratopalladium chelate complex is replaced with the carboxylato group and converted into the dicarboxylatopalladium chelate complex. The above complex can be isolated as a pure product by removing an inorganic salt insoluble in an organic solvent from the reaction solution and then recrystallizing it from an appropriate solvent such as a mixed solvent of chloroform / n-hexane.

When the dinitratopalladium chelate complex is a dinitratopalladium bis chelate complex, a dicarboxylatopalladium chelate complex is produced and a basic bidentate ligand is released. The basic bidentate ligand can be recovered by recrystallizing the dicarboxylatopalladium chelate complex and separating and recovering it, and then recrystallizing it from the mother liquor using an appropriate solvent such as n-hexane.

The dicarboxylatopalladium chelate complex produced by the above reaction is a monochelate complex, and is not converted to a bis chelate complex even when an excessive basic bidentate ligand is present in the reaction solution.

[Effects of the Invention] By the method of the present invention, the anion part of the dinitratopalladium chelate complex having a long induction period in the oxidative coupling reaction of o-phthalic acid diester is replaced with a dicarboxylatopalladium complex having a short induction period. can do.

Next, examples and comparative examples of the present invention will be shown.

Example 1 0.591 g of bis (1,10-phenanthroline) dinitratopalladium was added to 20 m of acetic acid and N / 2-KOH-.
When heated together with 8 m of the ethanol solution, a uniform solution is obtained. After refluxing for 2 hours, the resulting reaction solution was evaporated to dryness. Dissolved in 10m of chloroform, 0.47
1 g was filtered off. The IR spectrum confirmed that the insoluble matter was potassium nitrate. N-hexane 2 in the filtrate
0 m was added and the mixture was allowed to stand in a refrigerator (-10 ° C), the deposited precipitate was separated by filtration, washed with n-hexane and dried,
353 g of product was obtained. The product was confirmed by IR spectrum and elemental analysis to be 1,10-phenanthrolinediacetatopalladium (yield 87
%). The results of elemental analysis are shown below.

The above product was filtered off and the filtrate was evaporated to dryness to obtain 10 parts of n-hexane.
m was added and left in the refrigerator (-10 ° C). The deposited precipitate was separated by filtration to obtain 0.094 g of a by-product. The IR spectrum of the by-product was in agreement with the authentic 1,10-phenanthroline.

Example 2 0.543 g of bis (2,2′-bipyridine) dinitratopalladium was refluxed with 20 m of acetic acid and 4 m of N / 10-KOH-ethanol solution for 30 minutes. The obtained reaction solution was treated in the same manner as in Example 1 to obtain 0.334 g of a product. From the IR spectrum and elemental analysis, the product was confirmed to be 2,2′-bipyridine diacetatopalladium (yield 88%). The results of elemental analysis are shown below.

The filtrate obtained by filtering the above product was treated in the same manner as in Example 1 to obtain 0.33 g of a by-product. The IR spectrum of the by-product was in agreement with the authentic 2,2'-bipyridine.

[Example 3] 1,10-phenanthroline dinitratopalladium
411 g was refluxed with 20 m of acetic acid and 20 m of N / 10-KOH-ethanol solution for 30 minutes to obtain a yellow homogeneous solution. The homogeneous solution was evaporated to dryness using an evaporator and then dissolved in 10 m of chloroform to give an insoluble matter of 0.
191 g was filtered off. The IR spectrum confirmed that the insoluble matter was potassium nitrate. 20 m of n-hexane was added to the filtrate, the mixture was left in a refrigerator (-10 ° C), the deposited precipitate was filtered off, washed with n-hexane and dried,
0.390 g of product was obtained. The product was confirmed to be 1,10-phenanthroline diacetatopalladium by IR spectrum and elemental analysis (yield 9
6%). The results of elemental analysis are shown below.

[Example 4] The procedure of Example 3 was repeated except that 0.5 g of potassium bicarbonate was used instead of 20 m of the N / 10-KOH-ethanol solution, and 1,10-phenanthroline diacetatopalladium. 377 g was obtained (93% yield).

[Example 5] The same treatment as in Example 3 was carried out except that 0.196 g of potassium acetate was used instead of 20 m of the N / 10-KOH-ethanol solution, and 0.386 g of 1,10-phenanthroline diacetatopalladium. Was obtained (yield 95%).

[Example 6] The same procedure as in Example 3 was repeated except that 0.164 g of sodium acetate was used instead of 20 m of the N / 10-KOH-ethanol solution, and 0.376 g of 1,10-phenanthroline diacetatopalladium was used. Was obtained (yield 93%).

[Example 7] 2,2'-bipyridine dinitratopalladium 0.387
g of acetic acid 20 m and N / 2-KOH-ethanol solution 4
Reflux with m for 30 minutes. The obtained reaction liquid was treated in the same manner as in Example 3 to obtain 0.347 g of a product. From the IR spectrum and elemental analysis, the product was
It was confirmed to be 2'-bipyridine diacetatopalladium (yield 91%). The results of elemental analysis are shown below.

[Comparative Example 1] 1,10-phenanthroline dinitratopalladium
Although 411 g was refluxed with 20 m of acetic acid for 5 hours without adding an alkali, a uniform solution was not obtained, and 0.392 g of a solid insoluble in acetic acid was obtained. The solid was 1,10-phenanthroline dinitratopalladium as a starting material by IR spectrum and elemental analysis.

[Comparative Example 2] 2,2'-bipyridine dinitratopalladium 0.773
20 g of acetic acid was added to g and refluxed for 2 hours without adding an alkali to obtain a uniform solution. Allowing the homogeneous solution to cool,
0.760 g of a precipitated yellow solid was obtained. The solid is IR
From the spectrum and elemental analysis, the starting material 2,2'-
It was bipyridine dinitratopalladium.

[Brief description of drawings]

Fig. 1 shows the results of using a palladium chelate complex as a catalyst.
It is a figure which shows the time-dependent change curve of the yield of 3,3 ', 4,4'-biphenyl tetracarboxylic acid tetramethyl at the time of performing the oxidative coupling reaction of o- dimethyl phthalate at 00 degreeC. Fig. 2 shows the results of using a palladium chelate complex as a catalyst.
It is a figure which shows the time-dependent change curve of the yield of 3,3 ', 4,4'-biphenyl tetracarboxylic acid tetramethyl at the time of performing the oxidative coupling reaction of o- dimethyl phthalate at 20 degreeC.

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Claims (6)

[Claims] 1. A compound represented by the general formula [I]: L _x .Pd (NO ₃ ) ₂ ... [I] (wherein L represents a basic bidentate ligand, and x is 1 or 2). The dinitratopalladium chelate complex represented by RCOOH is reacted with an aliphatic carboxylic acid represented by RCOOH in the presence of an alkali to give a compound represented by the general formula [II]: L · Pd (RCOO) ₂ ... [II] (however, A method for producing a palladium chelate complex, wherein L is a basic bidentate ligand and R is an alkyl group). 2. The method for producing a palladium chelate complex according to claim 1, wherein the dinitratopalladium chelate complex is a dinitratopalladium bis chelate complex. 3. The method for producing a palladium chelate complex according to claim 1, wherein the basic bidentate ligand is 1,10-phenanthroline or 2,2'-bipyridine. 4. The method for producing a palladium chelate complex according to claim 1, wherein the reaction is carried out at a temperature in the range of 20 to 250 ° C. 5. The method for producing a palladium chelate complex according to claim 1, wherein the reaction is carried out under reflux of an aliphatic carboxylic acid. 6. The method for producing a palladium chelate complex according to claim 1, wherein the aliphatic carboxylic acid is acetic acid.