JPH0471900B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is represented by the structural formula [] 3,5,6-tricarboxynorbornane-2
- This invention relates to acetic acid (hereinafter abbreviated as tetracarboxylic acid) and its production method. The compound of the present invention is a new compound, and this type of tetracarboxylic acids is generally used as a plasticizer for polyimide resins and polyvinyl chloride for the purpose of heat resistance.
It is used in a wide range of fields as a curing agent for epoxy resins and as a raw material for water-soluble polyesters. However, the currently widely used aromatic tetracarboxylic acids such as pyromellitic acid and benzophenonetetracarboxylic acid have high melting points, poor solubility in solvents, and are too reactive, making them difficult to work with. There was a problem. Furthermore, it is expensive, and a new type of tetracarboxylic acid with improved costs has been long awaited. The compounds of the present invention are cycloaliphatic tetracarboxylic acids that are prepared by two routes as shown in the following schemes.

[Table] It is also an economical tetracarboxylic acid that can be produced in a short number of steps using inexpensive dicyclopentadiene (DCPD) as a starting material. Further, due to the characteristics of alicyclic compounds, improved performance such as a lower melting point, improved solubility in solvents, and moderated reactivity is expected. The method for producing the diester, which is the starting material for the present compound (Japanese Patent Application No. 190429/1982), is synthesized by the diesterization reaction of dicyclopentadiene, which was discovered by the present inventors. (R is alkyl, cycloalkyl,
Benzene-substituted alkyl may contain O and N atoms internally. ) This diesterification method is a Watzker-type reaction using a catalyst system of palladium chloride-copper chloride and/or oxygen, which proceeds easily even under mild conditions at room temperature and pressure, and has an extremely high yield. As mentioned above, there are two methods for producing tetracarboxylic acid from this diester. One route is to oxidatively cleave the carbon-carbon double bond of the diester to obtain DEDC, and then hydrolyze this ester group to obtain a tetracarboxylic acid, and the other route is to hydrolyze the ester group of the diester. is carried out first to obtain dicarboxylic acid, followed by carbon,
This route involves oxidative cleavage of carbon double bonds to obtain tetracarboxylic acids. Hydrolysis of ester groups by these two routes easily proceeds in the presence of ordinary acids or alkalis. When using an acid, it is preferable to use an aqueous solution such as hydrochloric acid or sulfuric acid, and when using an alkali, it is preferable to use a water-alcoholic solution such as sodium hydroxide or potassium hydroxide. Next, as a method for oxidative cleavage of carbon-carbon double bonds, a method using nitric acid is generally used [Journal of Industrial Chemistry, Vol. 74, 397
(1971)], permanganate method [J.Am.Chem.Soc, Vol. 82, p. 6342 (1960)
)] Liquid phase catalytic co-oxidation method using metal catalysts [JP-A-Sho
55-162737], and an ozone oxidation method [J. Am. Chem. Soc, Vol. 81, p. 4273 (1959)]. The present inventors have investigated various oxidative cleavage reactions of diesters and dicarboxylic acids, and have found that methods using nitric acid or permanganate are difficult to obtain the desired product, but co-oxidation methods or ozone oxidation methods are highly effective. It has been found that the ozone oxidation method in particular gives excellent results. Regarding the ozone oxidation method, it is preferable to use an ordinary ozone generator to perform the ozone generation method using oxygen in a cylinder.If air is used, after ozonation, nitrogen oxides are removed by alkaline washing, etc., and then dried. It is necessary to use the Hydrocarbons, halogenated hydrocarbons,
Although inert solvents such as ethers and esters may also be used, it is preferable to use brotic active solvents such as alcohols and carboxylic acids because of the risk of abnormal reactions. In particular, alcohols are preferred because they allow reaction at low temperatures, and specifically methanol, ethanol, propanol, butanol, etc. give good results. The ozone addition temperature is preferably low in order to suppress abnormal reactions, and in particular, around -78°C provides high selectivity. Oxidative decomposition of the obtained ozonide is mainly carried out with oxygen, but it can also be carried out with peracetic acid, performic acid, hydrogen peroxide, etc. Next, the liquid phase catalytic oxidation method is carried out by contacting a molecular oxygen-containing gas in the presence of a catalyst and a co-oxidizing agent, but in addition to pure oxygen, an oxygen mixed gas diluted with an inert gas such as nitrogen or argon is used. Or air can also be used. The gas can be supplied by two methods: bubbling in a normal pressure flow system and under pressure using an autoclave. As the catalyst, metals such as ruthenium and osmium, or compounds thereof can be used. However, osmium is not practical due to its toxicity. Examples of ruthenium that can be used include metal ruthenium, ruthenium oxide, ruthenium halide, ruthenium hydroxide, and ruthenium complexes. Specifically, ruthenium sesquioxide, ruthenium dioxide,
Ruthenium tetroxide, ruthenium chloride, ruthenium bromide, ruthenium iodide and the like are preferred. The amount used is approximately 0.0001 to 0.01 gram atom in terms of ruthenium metal per mole of raw material diester or dicarboxylic acid. The aldehyde or ketone used as the co-oxidizing agent may be either aliphatic or aromatic. Specifically, formaldehyde, paraformaldehyde, acetaldehyde, paraaldehyde, glyoxal, propionaldehyde, benzaldehyde, tolualdehyde, methyl ethyl ketone, methyl isobutyl ketone, biacetyl,
Examples include cyclohexanone and methylbenzyl ketone. Among these, aliphatic aldehydes are preferred, and acetaldehyde is particularly economical and excellent. The amount of these aldehydes or ketones used is 0.5 per mole of raw material diester or dicarboxylic acid.
It is preferably about 100 moles. Although this reaction can be carried out without using a solvent, it is usually preferably carried out in the presence of a solvent. A wide range of solvents can be used as long as they are inert to the reaction, and examples include halogenated hydrocarbons, aliphatic and aromatic hydrocarbons, esters, carboxylic acids, ethers, alcohols, and ketones. . Among these solvents are acetone, ethyl acetate,
Particular preference is given to using acetic acid, methanol and the like. Further, the reaction temperature is preferably from 0°C to 200°C. When the raw material is a diester, the oxidative cleavage product obtained by the ozone oxidation method or the liquid phase co-oxidation method is
When the raw material is dicarboxylic acid, the desired tetracarboxylic acid can be obtained as is. Tetracarboxylic acid can be purified by the following method. Tetracarboxylic acid is heated and dehydrated under reduced pressure to obtain 3,5,6-tricarboxynorbornane-2-acetic acid-5,6- represented by the structural formula [].
Convert to anhydride (abbreviated as monoanhydride). By recrystallizing this reaction product from ethyl acetate, monoanhydride crystals are obtained. Subsequently, this pure monoanhydride was hydrated in the presence or absence of an acid to obtain a pure tetracarboxylic acid. Hydration of monoanhydride can be carried out by adding a small amount of acid such as hydrochloric acid or nitric acid to 1 mol or more of water and reacting with 1 mol of monoanhydride when an acid is present.
The reaction is completed in a short time. Even in the absence of acid, hydration can be easily achieved by reacting at 70 to 80°C. After the reaction was completed, pure white tetracarboxylic acid was obtained by removing excess water and acid. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Reference example 1 Synthesis of dimethyl ester (under pressure) 3.95 g of dicyclopentadiene (DCPD) was placed in a Hastelloy autoclave with an internal volume of 100 ml.
(30mmol), palladium chloride 0.267g (1.5mmol),
Anhydrous cupric chloride (purity 95%) 10.4g (73mmol),
Prepare 24g of methanol and make 35kg of carbon monoxide/
After pressurizing to cm ² ·G, stirring was started at room temperature (25°C). Absorption of carbon monoxide started immediately and stopped at 5 kg/cm ² ·G after 15 minutes. The reaction was exothermic and the autoclave reached a maximum temperature of 48°C. Stirring was stopped 30 minutes after starting the reaction, the temperature was returned to room temperature, carbon monoxide was removed, and the reaction product was taken out. After removing the solvent from the reaction mixture; extraction was performed with n-hexane. As a result of analyzing this n-hexane solution with a gas chromatograph, no dicyclopentadiene as a raw material remained and an almost monopeak was detected as a product. Therefore, this reaction was repeated 5 times in exactly the same manner, and the n-hexane solution for the 5 reactions was concentrated and further distilled under reduced pressure to obtain 33 g of dimethyl ester (purity 98%) at 140-145°C/0.7 mmHg. Reference Example 2 Synthesis of dimethyl ester (under normal pressure) Into the glass four-necked flask from Step 2, add 212 g (1.6 mol) of dicyclopentadiene (DCPD), 4.0 g (0.023 mol) of palladium chloride, and anhydrous cupric chloride (purity 95).
%) 465g (3.5mol) and 800g of methanol were heated to 50°C, then carbon monoxide was added to the mixture under normal pressure.
Bubbling was carried out for 2 hours while stirring at a flow rate of 1 min. After the reaction, the reaction product was cooled and the solvent was removed, followed by extraction with n-hexane. After concentrating this n-hexane solution, it was distilled under reduced pressure to a temperature of 135 to 143℃/
284g dimethyl ester (98% purity) at 0.5mmHg
I got it. Reference example 3 Synthesis of dicarboxylic acid An aqueous solution of 64 g (1.6 mol) of sodium hydroxide dissolved in 150 ml of water and 102 g of dimethyl ester (purity
A solution of 98%) (0.4 mol) dissolved in 400 g of ethanol was mixed and refluxed at 78°C for 3 hours, then the ethanol was removed, and the residue was concentrated with 165 g of concentrated hydrochloric acid to remove water. The obtained concentrate was extracted with acetone, and the acetone solution was concentrated to obtain 85 g of crude dicarboxylic acid. By recrystallizing this with acetonitrile solvent, white crystals of dicarboxylic acid were obtained. Melting point 167-168℃. Example 1 Synthesis of tetracarboxylic acid from dimethyl ester 51 g (purity 98%) (0.2 mol) of dimethyl ester and methanol were placed in a 500 ml glass cylindrical gas absorption tube.
Charge 300g and cool to -78℃. Ozone generator (Japan Ozone Co., Ltd. model 0-1-2)
Inject 45/hr of ozone-containing oxygen from 100V)
The reaction was allowed to proceed for 12 hours. This reaction solution was concentrated under reduced pressure at 50° C. or lower to obtain a water syrup-like ozonide. When this ozonide is dissolved in 306 g of formic acid and 25 g of 60% hydrogen peroxide is added at around 50°C, reflux begins shortly after. When reflux stops, add another 20 g of 60% hydrogen peroxide, gradually raise the temperature to 120°C, and react for 2 hours. After the reaction, the solvent was removed under reduced pressure to obtain a highly viscous liquid. The analysis results of this product were as follows. IR (KBr): 3000-2900, 1700, 1200 (cm ^-1 ) Mass spectrum: Measured after silylation with bis(trimethylsilyl)acetamide. [m/e (%)]: 458(2), 443(100), 368(12)335
(35), 185(30), 73(30) From the above, this highly viscous liquid is 3,5,6-tricarboxynorbornane-2-acetic acid-5,6-dimethyl ester (hereinafter abbreviated as DEDC). It turns out that there is something. 200% ethanol to this crude DEDC
An aqueous solution of 32 g of sodium hydroxide dissolved in 100 g of water was added thereto, and reflux was continued for 3 hours with stirring at a bath temperature of 120°C. Then remove the ethanol and add concentrated hydrochloric acid (35% HCl) 83
After neutralizing by adding g, the water is distilled off. This residue was extracted with acetone and the acetone solution was concentrated to obtain 52 g of crude crystals of the desired tetracarboxylic acid. Subsequently, the crude crystals were heated under reduced pressure at around 100°C for 2 hours and then recrystallized from an acetone-ethyl acetate solvent to obtain 3,5,6-tricarboxynorbornane-2-acetic acid-5,6-anhydride (monoacetic acid). anhydride)
39 g of pure product (100% purity) was obtained. Next, add 30g of water to 10g of monoanhydride and heat to 100℃.
After stirring for 2 hours, it completely dissolved and became homogeneous.
Subsequently, excess water was removed to obtain 10 g of pure white crystals. The following analysis was performed on this crystal. IR (KBr): 3200~2500, 1700, 1420, 1260,
1220, 920 (cm ^-1 ) ¹³ C-NMR (CD ₃ COCD ₃ ): 174.7, 174.5,
174.0, 46.2, 45.8, 45.5, 45.2, 45.1, 44.6,
44.4, 44.1, 37.9, 37.4, 37.1, 35.8, 32.7
(ppm) Mass spectrum: Measured after silylation with bis(trimethylsilyl)acetamide. [m/e (%)]: 574 (15), 559 (100), 484 (30)
，
394 (40) Elemental analysis: C ₁₂ H ₁₄ O ₆ = 286.24

[Table] Melting point: 75-85°C From the above, it was found that this crystal was 3,5,6-tricarboxynorbornane-2-acetic acid. Example 2 Synthesis of tetracarboxylic acid from dicarboxylic acid 22 g (purity 100%) (0.1 mol) of dicarboxylic acid and 300 g of methanol were placed in a 500 ml glass cylindrical gas absorption tube.
g was charged, and 45/hr of ozone-containing oxygen from an ozone generator cooled to -78°C was blown into the reactor to react for 5 hours. This reaction solution was concentrated under reduced pressure at 50° C. or lower to obtain a water syrup-like ozonide. Next, this ozonide is mixed with formic acid.
20g of 60% hydrogen peroxide dissolved in 150g at around 50℃
When added, reflux begins. When the reflux stops, raise the bath temperature to 120℃ and
Reflux was continued for an hour. Next, the solvent was distilled off under reduced pressure to obtain 26 g of white crude tetracarboxylic acid crystals. The crude crystals were silylated with bistrimethylsilylacetamide and analyzed using gas chromatography, and the yield was 88%. Example 3 Synthesis of tetracarboxylic acid from dimethyl ester 25 g of acetaldehyde and ruthenium dioxide (RuO ₂ 2H ₂ O) were placed in a 300 ml four-necked glass reaction flask.
0.1 g and 100 g of acetone were charged at 40°C, and oxygen gas was blown in at a rate of 30/hr for 1.5 hours. Next, add 5.0g of dimethyl ester to this solution.
(0.02mol) dissolved in 20g of acetone.
The mixture was added dropwise over a period of time and stirred for an additional 2 hours. After the reaction, remove the ruthenium catalyst and add 30ml of water to the solution.
and stir for 2 hours at a bath temperature of 60°C. Concentrate this reaction solution and dissolve the obtained DEDC in 20 g of ethanol. An aqueous solution of 3.2 g of sodium hydroxide dissolved in 10 g of water was added to this ethanol solution, and reflux was continued for 2 hours with stirring at a bath temperature of 120°C. After finishing, remove the ethanol and add concentrated hydrochloric acid (35%
After neutralizing by adding 8.3 g of HCl), water is removed.
This residue was extracted with acetone and the acetone solution was concentrated to yield 5.2 g of crude crystals of the desired tetracarboxylic acid.
was gotten. The crude crystals were silylated with bistrimethylsilylacetamide and analyzed using gas chromatography, and the yield was 69%. Example 4 Synthesis of tetracarboxylic acid from dicarboxylic acid 25 g of acetaldehyde and ruthenium dioxide (RuO ₂ 2H ₂ O) were placed in a 300 ml four-necked glass reaction flask.
0.1 g and 100 g of acetone were charged, and oxygen gas was blown in at a rate of 30/hr for 1.5 hours at 40°C. Subsequently, this solution was added dropwise over 1 hour to a solution of 4.5 g (0.02 mol) of dicarboxylic acid dissolved in 20 g of acetone, and the mixture was further stirred for 2 hours. After the reaction, the ruthenium catalyst was removed, 30 ml of water was added to the solution, and the mixture was stirred for 2 hours at a bath temperature of 60°C. When this reaction solution was concentrated, 4.8 g of crude crystals of tetracarboxylic acid were obtained. The crystals were silylated with bistrimethylsilylacetamide and analyzed using gas chromatography, and the yield was 76%. Example 5 In Example 1, 51 g of raw material dimethyl ester
was oxidized and hydrolyzed in exactly the same manner except that 67 g of dibutyl ester (purity 98%) was used to obtain 49 g of crude crystals of tetracarboxylic acid.

Claims (1)

[Claims] 1 Represented by the structural formula [] 3,5,6-tricarboxynorbornane-2
- Acetic acid (hereinafter abbreviated as tetracarboxylic acid). 2 Represented by structural formula [] (R represents alkyl) 3,5,6-tricarboxynorbornane-2
-Using acetic acid-5,6-diester (hereinafter abbreviated as diester) as a starting material, this double bond is oxidized and cleaved to form a structure represented by the structural formula []. 3,5,6-tricarboxynorbornane-2
- A method for producing a tetracarboxylic acid, which comprises obtaining acetic acid (hereinafter abbreviated as DEDC) and subsequently hydrolyzing an ester group. 3 Represented by structural formula [] tricyclo [5.2.1.0 ^2.6 ] dece-3 ^- ene-8,
A method for producing tetracarboxylic acid, which uses 9-dicarboxylic acid (hereinafter abbreviated as dicarboxylic acid) as a raw material and oxidatively cleaves the double bond. 4. The method for producing a tetracarboxylic acid according to claims 2 and 3, wherein the oxidative cleavage of the double bond of the diester and dicarboxylic acid is carried out by an ozone oxidation method. 5. Claims 2 and 3, characterized in that the oxidative cleavage of double bonds in diesters and dicarboxylic acids is carried out by liquid phase catalytic oxidation using a ruthenium compound, an aldehyde, a ketone, and molecular oxygen gas.
A method for producing a tetracarboxylic acid as described in .