JPH05246945A - Production of biphenyldicarboxylic acid - Google Patents

Abstract

PURPOSE:To efficiently produce high-purity biphenyldicarboxylic acid excellent in hue with a high recovery by oxidizing a di-substituted biphenyl, dissolving the resultant crude product in a mixture solvent of an amine and an alcohol and making it deposit therefrom. CONSTITUTION:A di-substituted biphenyl having two substituent groups capable of each converted into a carboxyl group by oxidation reaction is oxidized by molecular oxygen such as air in the presence of a heavy metal, bromine, etc., in a solvent such as an aliphatic lower monocarboxylic acid or water to obtain crude biphenyldicarboxylic acid. The resultant crude biphenyldicarboxylic acid is dissolved in a mixture solvent prepared by mixing an alkylamine with an alcohol in a weight ratio of (1:99) to (900:10), preferably (5:95) to (80:20) and deposited therefrom. The separated precipitate is washed with a substantially anhydraus acid and then dried, thus obtaining the objective purified biphenyldicarboxylic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing biphenyldicarboxylic acid. Biphenyldicarboxylic acid is a compound useful as a raw material for highly functional resins such as wholly aromatic polyesters.

[0002]

2. Description of the Related Art Biphenyldicarboxylic acid is generally produced by oxidizing a dialkyl-substituted biphenyl such as dimethylbiphenyl or diisopropylbiphenyl with molecular oxygen in the presence of cobalt, manganese and bromine. .. The crude biphenyldicarboxylic acid obtained by this method contains impurities such as monoalkylbiphenylcarboxylic acid, which is an intermediate of the oxidation reaction, and a coloring substance, and therefore requires a purification step.

Conventionally, as a method for purifying biphenyldicarboxylic acid, crude biphenyldicarboxylic acid is dissolved in an alkaline aqueous solution, and after treatment such as decolorization with activated carbon,
A method of obtaining highly pure biphenyldicarboxylic acid by making it acidic is known (JP-A-58-85841).
No. 2, JP-A-2-76837). However, this method has a problem that a large amount of inorganic salt and waste water are generated because a large amount of alkali and acid are used.

The crude biphenyldicarboxylic acid obtained by the coupling reaction of p-bromobenzoic acid is
A method of dissolving in N, N-dimethylformamide (DMF) and adding a poor solvent such as methanol for precipitation (JP-A-2-235843) or recrystallization of crude biphenyldicarboxylic acid using dimethylsulfoxide (DMSO) as a solvent. Alternatively, a method of re-precipitation for purification (Japanese Patent Laid-Open No. 57-1 / 1982)
No. 49244) is also disclosed.

However, in these methods, DMF is used.
Since the solubility of biphenyldicarboxylic acid in DMSO and DMSO is low, a large amount of solvent must be used.
DMF has a high boiling point and it is difficult to recover the solvent.
There were also problems such as high toxicity. On the other hand, JP-A-3-27
No. 9347 discloses that crude 4,4′-biphenyldicarboxylic acid is reacted with monoethanolamine in a solution form or a slurry form to form a monoethanolamine salt of the carboxylic acid, and the precipitated salt is separated to separate water. A method of releasing 4,4′-biphenyldicarboxylic acid and recovering it by acid precipitation after the decomposition by the method is disclosed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for easily producing a high-purity biphenyldicarboxylic acid having a good hue with a high recovery rate.

[0007]

Means for Solving the Problems The first object of the present invention is to dissolve a crude biphenyldicarboxylic acid obtained by oxidizing disubstituted biphenyls in a mixed solvent of alkylamines and alcohols, and cool it. The method for producing biphenyldicarboxylic acid, characterized in that the separated crystallization product is washed with a substantially anhydrous acid, and secondly, crude biphenyldicarboxylic acid obtained by oxidizing disubstituted biphenyls. The acid is dissolved in a mixed solvent of alkylamines and alcohols,
A method for producing biphenyldicarboxylic acid, which comprises crystallizing by adding a substantially anhydrous acid.

(Di-substituted biphenyls) The di-substituted biphenyls used in the method of the present invention can be converted to a carboxyl group by an oxidation reaction of an alkyl group, an acyl group, a formyl group, a hydroxyalkyl group, a hydroperoxyalkyl group or the like. Disubstituted biphenyls having two different substituents. The positions of the two substituents are not particularly limited, but are, for example, 2,3-position, 2,4-position, 2,5-position, 2,6-position.
Position, 3,4-position, 2,2'-position, 2,3'-position, 2,
4'-position, 3,3'-position, 3,4'-position, 4,4'-position and the like can be mentioned. Of these, 3,3'-position, 4,4'-
Position is particularly preferred.

(Crude biphenyldicarboxylic acid) The above-mentioned disubstituted biphenyls are oxidized with molecular oxygen such as air in a solvent such as aliphatic lower monocarboxylic acid and water in the presence of a catalyst such as heavy metal and bromine. Thus, crude biphenyldicarboxylic acid is obtained. Examples of the aliphatic lower monocarboxylic acid solvent include formic acid, acetic acid, propionic acid, butyric acid, valeric acid and bromoacetic acid. Among them, acetic acid is most preferable, and diluted with other solvent such as water or aromatic hydrocarbon. It may have been done. The amount of the solvent used is not particularly limited, but it is preferably 0.5 to 10 times by weight, particularly preferably 1 to 6 times by weight based on the starting di-substituted biphenyls.

Examples of heavy metals used as catalysts include cobalt and manganese. As the cobalt compound and the manganese compound, for example, cobalt and manganese formic acid, acetic acid, propionic acid, oxalic acid, aliphatic carboxylic acid salts such as maleic acid, alicyclic carboxylic acid salts such as naphthenic acid, benzoic acid, terephthalic acid, In addition to aromatic carboxylic acid salts such as naphthoic acid and naphthalenedicarboxylic acid, inorganic compounds such as hydroxides, oxides, carbonates and halides can be mentioned. Of these, acetate and bromide are particularly preferable.

The cobalt compound and the manganese compound are generally used as a mixture, and the mixing ratio thereof is cobalt: manganese (atomic ratio) in the range of 99: 1 to 1:99, preferably 95: 5 to 5:95. is there. The amount of cobalt and manganese used is in the range of 0.2 to 15% by weight, preferably 0.4 to 10% by weight, as the total amount of cobalt and manganese atoms, based on the aliphatic carboxylic acid solvent. As the bromine compound contained in the catalyst component, for example, molecular bromine, hydrogen bromide, alkali metal bromide, alkaline earth metal bromide, inorganic bromine compounds such as hydrobromide, and methyl bromide, ethyl bromide, Examples thereof include organic bromine compounds such as bromoform, ethylene bromide, and bromoacetic acid.

The amount of the bromine compound used is such that the amount of bromine atoms is 0.1 to 10 times the total number of moles of cobalt and manganese atoms contained in the aliphatic carboxylic acid solvent,
It is preferably in the range of 0.2 to 5 mol times. The reaction temperature is usually 100 to 300 ° C., and the pressure is preferably such that the oxygen partial pressure in the gas phase is 0.2 to 10 kg / cm ^{2 in} absolute pressure. After the completion of the oxidation reaction, the reaction solution is cooled to about room temperature and the precipitated solid is recovered to obtain crude biphenyldicarboxylic acid. The crude biphenyldicarboxylic acid thus obtained has a purity of 90% or more, generally 95 to 99%, and usually has a pale yellow to brown color, but is used as it is in the next crystallization step. Alternatively, the crystallization may be performed after washing with a reaction solvent or the like. In some cases, a hue of 99% or more, for example, activated carbon or biphenyldicarboxylic acid after being treated with DMF or the like can be crystallized to improve the hue.

(Alkylamines) Examples of the alkylamines used as a crystallization solvent in the method of the present invention include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-propylamine, di-n. -Propylamine, tri-n-propylamine, isopropylamine, diisopropylamine, triisopropylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, sec-butylamine, di-sec-butylamine, tri -Tert-butylamine, tert-butylamine, di-tert-butylamine, tri-tert-butylamine, n-hexylamine, di-n-hexylamine, tri-n-hexylamine, cyclohexylamine, dicyclohexylamine, Tricyclo Xylamine, n-octylamine, di-n-octylamine, tri-n-octylamine, ethylenediamine, N-methylethylenediamine, N, N-dimethylethylenediamine, N, N'-dimethylethylenediamine, N, N, N'- Trimethylethylenediamine, N, N, N ', N'-tetramethylethylenediamine, 1,2-diaminopropane, 1,3-
Diaminopropane, N-methyl-1,2-diaminopropane, N-methyl-1,3-diaminopropane, N, N
-Dimethyl-1,2-diaminopropane, N, N-dimethyl-1,3-diaminopropane, N, N, N'-trimethyl-1,2-diaminopropane, N, N, N'-trimethyl-1, 3-diaminopropane, N, N, N ',
N'-tetramethyl-1,2-diaminopropane, N,
Examples include N, N ', N'-tetramethyl-1,3-diaminopropane and the like. These amines can be used either individually or as a mixture of two or more kinds at any ratio.

(Alcohols) Examples of alcohols used as a crystallization solvent in the method of the present invention include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and sec-. Butyl alcohol, t-butyl alcohol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, t-
Aliphatic chain monoalcohols such as amyl alcohol, neopentyl alcohol, hexyl alcohol, pentyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol; alicyclic monoalcohols such as cyclopentyl alcohol, cyclohexyl alcohol; ethylene glycol, 1,2- Propylene glycol, 1,3
-Aliphatic chain diols such as propylene glycol;
1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclohexanediol, 1,
Alicyclic diols such as 3-cyclohexanediol and 1,4-cyclohexanediol; aliphatic polyols such as glycerin and pentaerythritol; and the like. These alcohols can be used either individually or as a mixture of two or more kinds at an arbitrary ratio.

(Mixed solvent) In the method of the present invention, crude biphenyldicarboxylic acid is dissolved in the mixed solvent of the above alkylamines and alcohols for crystallization. The mixing ratio of the alkylamines and the alcohols is 1:99 by weight.
It is in the range of 90:10, preferably 5:95 to 80:20.

The amount of the mixed solvent of the alkylamines and the alcohols used is sufficient to dissolve the crude biphenyldicarboxylic acid at the temperature at which the dissolution operation is performed, and the mixture of the alkylamines and the alcohols is used. It cannot be specified unconditionally because it depends on the ratio and the temperature at which it is dissolved, but it is usually 1 to 1 with respect to the crude biphenyldicarboxylic acid.
The amount is 00 times by weight, preferably 2 to 50 times by weight.
However, the amount of the alkylamines used is 1.0 to 20 mole times, preferably 1.5 to 15 mole times, as an amino group of the alkylamines, relative to the diphenylcarboxylic acid in the crude biphenyldicarboxylic acid, particularly preferably It is preferably in the range of 2.0 to 10 mol times. If the amount of the mixed solvent is less than the above range, a sufficient crystallization effect cannot be obtained, and even if it is used in excess of the above range, the crystallization effect does not change and the amount of solvent used increases, which is rather uneconomical. Is. The higher the melting temperature is, the better, but usually 0 to 3
It is carried out at 50 ° C. The pressure at this time is not particularly limited.

(Crystallization Operation) The crystallization operation of the present invention is carried out by the following procedure. That is, the crude biphenyldicarboxylic acid is dissolved in a predetermined amount of mixed solvent, and if there is insoluble matter, the insoluble matter is removed by filtration. At this time, if necessary, it may be treated with activated carbon or the like. When treating with activated carbon, a predetermined amount of activated carbon is added to a mixed solvent in which crude biphenyldicarboxylic acid is dissolved, and the mixture is heated and stirred and then filtered. Either the method of passing the mixed solvent may be used. Then, if necessary, the required amount of the mixed solvent may be recovered by an operation such as distillation, and the solution may be concentrated.

Then, in the first method, the mixed solvent in which the crude biphenyldicarboxylic acid is dissolved is cooled, and the biphenyldicarboxylic acid amine salt is crystallized and separated by filtration or the like. The cooling temperature is 40 ° C or more lower than the melting temperature, and is in the range of -40 to 100 ° C, preferably -20 to 80 ° C. The separated crystallized product is washed with a substantially anhydrous acid and dried to obtain a purified biphenyldicarboxylic acid.

Examples of the acid used for washing include aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, monochloroacetic acid, monobromoacetic acid, trifluoroacetic acid and trichloroacetic acid. Of these, acetic acid is particularly preferable. The amount of acid used for washing is in the range of 0.5 to 20 times by weight, preferably 1 to 10 times by weight, of the biphenyldicarboxylic acid obtained by crystallization and separation. There are no particular restrictions on the temperature and pressure during washing.

The washing method is not particularly limited, but crystallization,
By mixing the amine salt of biphenyldicarboxylic acid obtained by separation and a predetermined amount of acid, stirring at a predetermined temperature for a predetermined time, and separating by operations such as filtration, high-purity biphenyldicarboxylic acid can be obtained. it can. At this time, the acid used for washing may be diluted with an organic solvent such as alcohols, ketones, ethers, aliphatic hydrocarbons and aromatic hydrocarbons.

The stirring temperature of the amine salt and the acid during washing is not particularly limited, but is usually 0 to 200 ° C., preferably 20 to 100 ° C. The stirring time is also not particularly limited, but is usually 0.01 to 5 hours, preferably 0.1
~ 2 hours range.

When the acid is diluted with the above-mentioned organic solvent, the amount of the organic solvent used is usually 0.1 to 50 times by weight, preferably 0.5 to 50 times the amine salt of biphenyldicarboxylic acid.
It is in the range of 20 times the weight. The mother liquor of the mixed solvent after filtering the precipitated biphenyldicarboxylic acid contains impurities and coloring substances, but is usually used for repeated crystallization without any special treatment or after purification if necessary. be able to.

As a second method, a biphenyldicarboxylic acid can be precipitated by adding a substantially anhydrous acid to a mixed solvent solution of crude biphenyldicarboxylic acid. At this time, as a third method, substantially anhydrous acid may be added after cooling. Examples of the acid used for precipitating the biphenyldicarboxylic acid include aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, monochloroacetic acid, monobromoacetic acid, trifluoroacetic acid and trichloroacetic acid.

The amount of the acid used is 0.1 to 10 relative to the amines in the solution in which the crude biphenyldicarboxylic acid is dissolved.
Equivalent amount, preferably 0.3 to 6 equivalent amount. By the above operation, the precipitated biphenyldicarboxylic acid crystals are separated, washed with a solvent such as alcohol, and dried to obtain a purified biphenyldicarboxylic acid. The mixed solvent after the recovery of the biphenyldicarboxylic acid contains the acid used for precipitation and the organic solvent when an organic solvent for dilution is used, but each is separated by a separation operation such as distillation. It can be separated and reused.

[0025]

[Function] Biphenyldicarboxylic acids are DMF, DMS
It dissolves to some extent in O, N, N-dimethylacetamide (DMAc), pyridines, and ethanolamines, but hardly dissolves in other organic solvents and water. Therefore, even in amines and alcohols, each alone hardly dissolves (Comparative Example) and does not form a salt with amines. However, when a mixed solvent of amines and alcohols is used, surprisingly, the solubility of biphenyldicarboxylic acids is dramatically improved, and the temperature dependence of the solubility becomes extremely large, Crystallization purification of the crude biphenyldicarboxylic acid is very easy.

Further, by adding an acid such as an aliphatic carboxylic acid to the mixed solvent of the present invention, the solubility of the biphenyldicarboxylic acid is significantly reduced, so that a high-purity biphenyldicarboxylic acid having a good hue can be obtained. it can.

[0027]

According to the method of the present invention, a crude biphenyldicarboxylic acid containing impurities and a coloring component, which is obtained by an oxidation reaction of disubstituted biphenyl, is converted into a highly pure biphenyldicarboxylic acid having a good hue. It can be manufactured with high recovery rate by performing solid-liquid separation once. Further, since water is not used during the operation, the organic solvent used for the operation can be easily separated and purified, which is industrially very advantageous.

[0028]

EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples. The purity of biphenyldicarboxylic acid was measured by high performance liquid chromatography. In addition, as for the hue, 10 g of a 25% methylamine aqueous solution was added to 1 g of the sample.
It was dissolved in ml, and the absorbance at a wavelength of 500 nm (hereinafter abbreviated as OD) was measured using a 10 mm quartz cell and evaluated by the value.

(Reference example) 500 having a reflux condenser, a gas introduction pipe, a raw material feed pump, a back pressure regulator and an induction stirrer
In a titanium autoclave made of titanium, 200 g of acetic acid, 9.35 g (37.5 mmol) of cobalt acetate / tetrahydrate, 9.20 g (37.5 mmol) of manganese acetate / tetrahydrate and 2.23 g of potassium bromide (18. 8 mmol) and pyridine 5.93 g (75.0 mmol) were charged, the inside of the reaction system was replaced with nitrogen, and the system pressure was adjusted to 30 kg /
It was set to be cm ² GP. Heat the inner temperature to 200 ℃, the air pressure is 5Nl / min, the inner pressure is 30kg / cm ² G
It was supplied so as to be kept at P. When the system became stable, 89.4 g of 4,4'-diisopropylbiphenyl (37
(5 mmol) was continuously fed over 2 hours. 4,4'-
After the supply of diisopropyl biphenyl was completed,
Air supply was continued for 1 hour while maintaining the temperature at 30 kg / cm ² GP.

After completion of the reaction, the autoclave was cooled to room temperature, the precipitated solid matter was collected by filtration and washed with 40 g of acetic acid. When the solid was dried, it was a light brown solid 84.4.
g was obtained. The yield of this crude 4,4′-biphenyldicarboxylic acid was 90.3%, and the purity was 97.2%.
The OD was 0.305.

Example 1 A crude 4,4'-biphenyldicarboxylic acid 1 obtained in Reference Example 1 was placed in a 200 ml flask.
3.5 g, 27.0 g of methanol, and 27.0 g of triethylamine were charged and heated and dissolved at 80 ° C. next,
A column with a jacket pre-filled with 4 g of activated carbon was
Keep the temperature at 0 ° C., and mix the above solution with LHSV = 1.0 hr.
^-1 was passed. 63.2 g of the collected mixed solution was cooled to room temperature, and the precipitated crystals were filtered. At this time, the recovered filtrate was 42.5 g. 20.5 g of separated crystals
Then, 40 g of acetic acid was placed in the flask, washed at room temperature, the crystals were separated by filtration, and rinsed with 5 g of acetic acid. When the obtained crystals were dried under reduced pressure, 7.1 g of purified 4,4′-biphenyldicarboxylic acid was obtained. The recovery rate was 52.6%, the purity was 99.8%, and the OD was 0.067.

(Example 2) The crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example was added to a 100 ml flask.
0 g, methanol 35.0 g, and triethylamine 1
2.0 g was charged and dissolved at room temperature. Next, the column with a jacket filled with 4 g of activated carbon in advance was kept warm at 65 ° C., and the above-mentioned mixed solution was passed at LHSV = 1.0 hr ⁻¹ . After passing the whole amount, a mixed solution of 7.0 g of methanol and 2.4 g of triethylamine was further passed. 20.0 g of acetic acid was added to 58.8 g of the collected mixed solution to precipitate crystals, which was then filtered. The separated crystals were washed with methanol and dried to obtain 4.7 g of purified 4,4'-biphenyldicarboxylic acid. Recovery rate is 94.0%
The purity was 99.9% and the OD was 0.010.

(Example 3) The crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example was added to a 100 ml flask.
0 g, methanol 35.0 g, and triethylamine 1
0.0 g was charged and dissolved at room temperature. Next, the column with a jacket filled with 4 g of activated carbon was kept warm at 65 ° C., and the above-mentioned mixed solution was passed through at LHSV = 0.5 hr ⁻¹ . After passing the whole amount, a mixed solution of 7.0 g of methanol and 2.0 g of triethylamine was further passed. 30.0 g of acetic acid was added to 57.1 g of the collected mixed solution to precipitate crystals and then filtered. When the separated crystals were washed with methanol and dried, 4.2 g of purified 4,4'-biphenyldicarboxylic acid was obtained. Recovery rate is 82.0%
The purity was 99.7% and the OD was 0.013.

(Comparative Example 1) A 200 ml flask was charged with 1.4 of the crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example.
Charge 00 g and 60.0 g of methanol, and add 4 at 80 ° C.
After heating and refluxing for a period of time, the crude 4,4′-biphenyldicarboxylic acid was hardly dissolved and the crystallization operation could not be performed.

(Comparative Example 2) A 200 ml flask was charged with 1.4 of crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example.
80 g and triethylamine 60.0 g were charged, and 80
After heating and refluxing at 4 ° C. for 4 hours, the crude 4,4′-biphenyldicarboxylic acid was hardly dissolved and the crystallization operation could not be performed.

(Comparative Example 3) The crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example was added to a 200 ml flask.
Charge 0 g and 60.0 g of triethanolamine, 1
It melt | dissolved by heating at 00 degreeC for 30 minutes. The solution was cooled to room temperature, but no crystals were precipitated and the crystallization operation could not be performed.

(Comparative Example 4) The crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example was added to a 200 ml flask.
0 g and 60.0 g of a 20% triethylamine aqueous solution were charged, and the mixture was heated and dissolved at 100 ° C. for 30 minutes. The mixed solution was cooled to room temperature, but no crystals were precipitated and the crystallization operation could not be performed.

(Comparative Example 5) The crude 4,4'-biphenyldicarboxylic acid obtained in Reference Example was added to a 100 ml flask.
0 g, methanol 25.0 g, triethylamine 7.2
g and 0.5 g of activated carbon were charged and stirred at 80 ° C. for 1 hour. The mixture was cooled to room temperature and the activated carbon was filtered.
65.0 g of acetone was added, and the precipitated crystals were collected by filtration. Acetone (40.0 g) was added to the obtained crystals to wash them with heating, and after cooling and filtration and drying, 4.5 g of pale yellow crystals were obtained. The purity of this crystal was 53.4%, and a large amount of triethylamine remained.

Comparative Example 6 A crystallization operation was performed in the same manner as in Comparative Example 5 except that 60 g of toluene was used instead of acetone, but toluene was not uniformly mixed with the methanol / triethylamine mixed solvent, No crystals precipitated.

Comparative Example 7 A crystallization operation was performed in the same manner as in Comparative Example 5 except that 60 g of hexane was used instead of acetone, but hexane was not uniformly mixed with the methanol / triethylamine mixed solvent, No crystals precipitated.

(Comparative Example 8) A crystallization operation was performed in the same manner as in Comparative Example 5 except that 150 g of methanol was used instead of acetone, but no crystals were deposited at all. (Comparative Example 9) A crystallization operation was performed in the same manner as in Comparative Example 5 except that 150 g of distilled water was used instead of acetone, but no crystals were precipitated.

Claims (3)

[Claims] 1. A crude biphenyldicarboxylic acid obtained by oxidizing disubstituted biphenyls is dissolved in a mixed solvent of alkylamines and alcohols, crystallized by cooling, and the separated crystallization product is substantially obtained. A method for producing biphenyldicarboxylic acid, which comprises washing with an anhydrous acid. 2. A crude biphenyldicarboxylic acid obtained by oxidizing disubstituted biphenyls is dissolved in a mixed solvent of alkylamines and alcohols, and substantially anhydrous acid is added for crystallization. A method for producing biphenyldicarboxylic acid, which is characterized. 3. The method for producing biphenyldicarboxylic acid according to claim 2, wherein cooling is performed before the substantially anhydrous acid is added.