JPH0710831B2 - Oligomer purification and separation method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for purifying and separating a bifunctional sulfone oligomer having a phenolic hydroxyl group.

[Conventional technology]

The bifunctional sulfone oligomer having a phenolic hydroxyl group at both ends is useful as a reactant for the condensation polymerization reaction,
For example, it can be used as a raw material for heat-resistant polycarbonate or polyester.

Prior art of aromatic sulfone oligomers is described in British Patent No. 1286.
No. 673 and Japanese Patent Publication No. 47-39598 and Japanese Unexamined Patent Publication No. 52-68292 disclose the same method. That is, the sulfone oligomer is an excess of bisphenol 2
Alkali salt and 4,4-dichlorodiphenyl sulfone,
By condensing in a polar solvent such as dimethyl sulfoxide, sulfolane, or dimethylacetamide, a solution of the sulfone oligomer 2 alkali salt in a polar solvent is first obtained, and this is stirred and mixed with acidic water such as dilute hydrochloric acid to remove the precipitated sulfone oligomer portion. It is obtained by a method of separating by filtration.

[Problems to be Solved by the Present Invention]

As described above, it is common to use acidic water for the precipitation of the sulfone oligomer, but it has the following drawbacks.

Substantially all of the oligomer component, raw material component, and by-product component are insoluble in acidic water, and all precipitate as a solid, so undesirable low molecular weight by-products and colored impurities are mixed in, and oligomer quality And spoil the aesthetics.
In particular, among the low molecular weight by-products, 4-chloro-4'-hydroxydiphenyl sulfone produced by hydrolysis of 4,4'-dichlorodiphenyl sulfone has a phenolic hydroxyl group only at one end, and therefore, for example, a sulfone oligomer. When used as a polymer raw material, it acts as a terminating agent and hinders the increase in molecular weight, which is extremely unfavorable.

The loosening of the precipitated sulfone oligomer is bad, and the high boiling point polar solvent used for the reaction in the precipitate is likely to remain, so not only does it take a long time to dry the sulfone oligomer, but the solvent component decomposes and gives off a bad odor. .

The high boiling polar solvent used for the sulfone oligomer formation reaction is mixed with a large amount of acidic water, so in order to recover the solvent, first, a large amount of water is evaporated and then the solvent is distilled and recovered. , Which results in a large energy loss.

In order to further improve the usefulness of the sulfone oligomer, the inventors of the present invention have conducted earnest research on a purification separation method in which the above-mentioned drawbacks are improved. As a result, a solution of the crude sulfone oligomer was converted into a monovalent C 1-5 containing acid. The above-mentioned problems have been eliminated by mixing the above-mentioned alcohol with the above and separating the precipitated sulfone oligomer solid by filtration.

[Means for solving problems]

That is, the present invention provides a polar solvent solution of a sulfone oligomer represented by the general formula [I] obtained by heating 4,4'-dichlorodiphenyl sulfone and an alkali salt of a bifunctional phenol in a polar solvent. Acid and carbon number 1
A method for purifying and separating a sulfone oligomer represented by the general formula [II], which comprises mixing with a monohydric alcohol of No. 5 and separating a precipitated solid content.

(In the formula [I], M is the same or different and is a hydrogen atom, a sodium atom or a potassium atom, and R is the same or different, Is shown, and 4 to 15 show an average degree of polymerization. ) (In the formula [II], R and R are the same as those in the formula [I].) The sulfone oligomer represented by the general formula [I] is 4,4 ′.
-Synthesized by heat condensation of dichlorodiphenyl sulfone and an alkali salt of a bifunctional phenol in a polar solvent.

Examples of such bifunctional phenols include 2,2-bis (4
-Hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, 4,4'-dihydroxydiphenyl, bis (4-hydroxy) Examples thereof include phenyl) ketone, bis (4-hydroxyphenyl) ether, hydroquinone and resorcin.

The alkali salt of a bifunctional phenol is a disodium salt or a dipotassium salt, but may be a mixture of a monoalkali salt and a dialkali salt.

As the polar solvent, dimethyl sulfoxide, sulfolane, dimethylacetamide, dimethylformamide, N
-Methylprolidone, N-methylcaprolactam and the like can be mentioned.

The heat condensation is performed at a temperature of 120 ° C. or higher and a temperature of the boiling point of the polar solvent or less, but in that case, if water is present, the formation of by-products becomes large, so that decompression or azeotropic dehydration may be performed in advance. desirable.

The obtained sulfone oligomer has a phenolic hydroxyl group or a sodium or potassium salt at both ends, as shown in the general formula [I]. Further, it has a statistical degree of polymerization distribution, and the average degree of polymerization can be used as a representative value thereof. This average degree of polymerization is 4,4'-
It is determined by the molar ratio of dichlorodiphenyl sulfone and an alkali salt of a bifunctional phenol. When the former mole number is a and the latter mole number is b, it can be expressed as = a / (ba).

When the value is less than 4, the ratio of low molecular weight components in the total oligomer becomes large, so that the effect of forming and separating is small. On the other hand, when it exceeds 15, the concentration of the phenolic hydroxyl group at the end of the oligomer becomes low and the sulfone content becomes low. Practicality as an oligomer becomes poor.

Thus, the sulfone oligomer represented by the general formula [I] of the present invention has a value of 4 to 15, preferably 5 to 13.

Thus, the sulfone oligomer represented by the general formula [I] is obtained as a solution in a polar solvent, but since it contains sodium chloride or potassium chloride produced during condensation, it may be separated by filtration or centrifugal precipitation if necessary. To do.

A solution of the sulfone oligomer in a polar solvent is mixed with an acid and a monohydric alcohol having 1 to 5 carbon atoms to precipitate the sulfone oligomer.

This acid is an inorganic acid or organic acid which is soluble in the alcohol, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, propionic acid, oxalic acid, and the like, and particularly hydrochloric acid, nitric acid, phosphoric acid, and acetic acid. Preferably, the amount used is at least twice the mole of the sulfone oligomer and at most 5% by weight of the alcohol.

The monohydric alcohol having 1 to 5 carbon atoms is methanol, ethanol, normal or isopropanol, normal, tertiary or isobutanol, and pentanol, and particularly methanol, ethanol and normal propanol are preferable, and the amount thereof is usually , The same amount or more as the polar solvent, and preferably 2 to 20 times by volume.

The order of mixing the acid and the monohydric alcohol having 1 to 5 carbon atoms in the polar solvent solution of the sulfone oligomer represented by the general formula [I] is as follows. The addition method and the method of mixing the acid and the monohydric alcohol and then mixing the polar solvent solution of the sulfone oligomer are preferable.

Mixing is usually carried out by mechanical stirring such as a rotary or reversing stirrer.

The precipitated solid is separated from the solution portion by a method such as filtration, precipitation, centrifugal filtration, and centrifugal precipitation. Further, the solid is washed with water or a monohydric alcohol to sufficiently remove the inorganic acid and polar solvent. be able to.

Thus, the purified sulfone oligomer represented by the general formula [II] in the form of particles or powder is obtained.

[Action and effect]

According to the present invention, a sulfone oligomer having high quality and excellent appearance can be separated in high yield.

This is because the monohydric alcohol not only dissolves low molecular weight components, by-products and colored impurities, but also precipitates the main oligomer component, while the acid not only changes the oligomer terminal from an alkali salt to a phenolic hydroxyl group, but also as a solution. This is because it has the effect of precipitating the effective oligomer component remaining in the part and improving the oligomer yield, and it is considered that these exert complementary effects to each other.

The sulfone oligomer thus obtained is not colored and has very little residual polar solvent, so it can be easily and sufficiently dried by ordinary hot air drying, and the residual solvent is thermally decomposed to give off a bad odor. Is almost never generated. It is considered that this is also because the surface structure of the sulfone oligomer separated by the method of the present invention is porous. Furthermore, since there is no low molecular weight by-product that acts as a terminating agent, it is extremely suitable as a polymer raw material or the like.

Further, in the method of the present invention, since the polar solvent is mixed with the monohydric alcohol and left, the energy required for recovering the polar solvent is extremely small as compared with the case where the polar solvent is mixed with a large amount of water as in the conventional method. That is, when the polar solvent is separated from these mixed liquids by ordinary distillation, the monohydric alcohol or water is first evaporated and separated, and then the polar solvent is distilled.
Since there is a large difference in the latent heat of vaporization between the alcohol and water, the energy required to recover the polar solvent is halved.

As described above, the method of the present invention is industrially excellent from the viewpoints of purification, drying, and energy saving of the sulfone oligomer.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to Examples.

In Tables 2 and 3, the analytical value of the oligomer component is the area% of the chromatograph for refractive index detection by PGC analysis, and CH is the by-product 4-chloro-4'-hydroxydiphenyl. , BA is the raw material 2,2-bis (4
-Hydroxyphenyl) propane, and n represents the value of n in the following general formula.

Reference Example 1 (Production of Sulfone Oligomer-1) 400.0 g (1.752 mol) of 2,2-bis (4-hydroxyphenyl) propane in a reaction flask having an internal volume of 3 equipped with a dropping funnel, a stirrer, a thermometer and a Dean Stark trap. ), Dimethyl sulfoxide 1120 ml, chlorobenzene 15
20 ml was charged and purged with pure nitrogen.

After heating the system to 70 ° C, 278.3 g (3.401 mol) of 48.9% by weight sodium hydroxide aqueous solution was added, and the mixture was further heated at 150 to 160 ° C for 6
After heating for an hour, chlorobenzene and water were distilled off as an azeotrope. Next, after cooling the system to 130 ° C., 447.4 g (1.558 mol) of 4,4′-dichlorodiphenyl sulfone was added over 1 hour, and the mixture was further stirred at 170 ° C. for 4 hours to produce a sulfone oligomer. After completion, the system was cooled to room temperature.

As a result, 1792 g of a solution of sulfone oligomer sodium salt in dimethyl sulfoxide was obtained.

The average degree of polymerization of the sulfone oligomer obtained from this is 8.0 (average molecular weight 3769), and the theoretical yield is 733.8 g.
Is.

Example 1 The solution obtained in Reference Example 1 was mixed with phosphoric acid (85
%) 45 ml and methanol 15 were slowly added, the precipitated solid matter was separated by filtration, and further washed with 15 times of water with stirring three times. Further solids were dried in two stages as follows.

1st stage 110 ° C, 12 hours in air 2nd stage 130 ° C, 48 hours in vacuum The amount of solids obtained (hereinafter referred to as the solid part) is 1
707.7 g in both the 2nd and 1st steps, which corresponds to 96.5% of the theoretical yield.

On the other hand, the filtrate after separation by filtration was distilled under reduced pressure, the remaining solution was added to a mixed solution of 200 ml of hydrochloric acid and 10 water, and the precipitate was filtered, washed with water, and dried (at 120 ° C. under air for 12 hours). Hereinafter, this is referred to as a soluble part) to obtain 22.1 g. This corresponds to 3.0% of theoretical yield.

The results of the analysis of the solid part and the soluble part were as shown in Table 1.

Next, an aromatic polyester was synthesized using the solid part obtained above.

Solid part 56.5 g, triethylamine 3.34 g (3.3 mmol)
Was dissolved in 210 ml of dichloromethane. To this solution, 25 ℃
While measuring the torque viscosity of the solution, a 1: 1 mixture of terephthaloyl chloride and isophthaloyl chloride was added little by little, and the addition was stopped when the torque reached its maximum value. The total amount of additives was 3.05 g (15.0 mmol).

The polymer solution thus obtained was precipitated with a mixed solution of 500 ml of acetone, 500 ml of methanol and 10 ml of concentrated hydrochloric acid, filtered, washed twice with water and further dried at 150 ° C. for 24 hours to obtain 55.6 g of polyester (yield: 95.2%). The logarithmic viscosity of this polymer (value measured in a 1: 1 mixture of parachlorophenol and orthochlorophenol at a concentration of 1.0 g / dl and a temperature of 25 ° C.) was 0.94.

Comparative Example 1 The oligomer was separated and produced in the same manner as in Example 1 except that a mixed solution of concentrated sulfuric acid 80 ml and water 20 was used instead of the mixed solution of phosphoric acid and methanol.

The weight of the solid matter obtained by the first-stage drying was 732.1 g, and the weight of the solid matter obtained by the second-stage drying (hereinafter referred to as the solid part) was 728.1 g. It was not enough.

The results of analyzing the solid part were as shown in Table 1.

Next, using the solid portion obtained above, an aromatic polyester was synthesized in the same manner as in Example 1.

The point where the torque shows the maximum value is 3.50 g (17.17) of a 1: 1 mixture of terephthaloyl chloride and isophthaloyl chloride.
2 mmol) was added.

The polymer yield was 55.2 g, the yield was 94.0%, and the inherent viscosity was 0.81, which was lower than that of the polymer obtained in Example 1.

Reference Example 2 (Production of sulfone oligomer-2) 24.93 g (0.1092 mol) of 2,2-bis (4-hydroxyphenyl) propane was added to a reaction flask having an internal volume of 0.5 equipped with a dropping funnel, a stirrer, a thermometer and a Dean Stark trap. ), 4,4'-dichlorodiphenyl sulfone 26.88 g (0.0
936 mol), 63.3 g of dimethyl sulfoxide, and 90.0 g of chlorobenzene were charged, and the atmosphere was replaced with pure nitrogen.

After heating the system to 70 ° C., 17.48 g (0.2183 mol) of 49.95 wt% sodium hydroxide aqueous solution was added, and the mixture was further heated to 145 ° C. for 15 hours to distill off chlorobenzene and water as an azeotrope.

After further stirring at 145 to 160 ° C. for 2.5 hours to complete the reaction for forming the sulfone oligomer, the system was cooled to room temperature.

From the above, sulfone oligomers (average degree of polymerization = 6.
A solution of a disodium salt in dimethylsulfoxide having a molecular weight of 0 and an average molecular weight of 2883) was obtained.

Example 2 The solution obtained in Reference Example 2 was slowly added to a mixed solution of 30 ml of acetic acid and 0.5 of methanol that was subjected to intensive stirring by inversion, and the white solid matter that precipitated was filtered and separated from the filtrate.

The solid was washed with 0.1N hydrochloric acid (1) and water (2) with stirring twice, and then dried under vacuum at 120 ° C. for 12 hours.
42.7 g of a solid part having the composition shown in Table 2 was obtained.

On the other hand, the filtrate was distilled under reduced pressure to remove methanol, and the remaining solution was added to 0.1N hydrochloric acid water 0.5, and the precipitate was filtered, washed with water and dried (120 ° C for 6 hours). 2.2 g of the soluble portion having the above composition was obtained.

Comparative Example 2 A sulfone oligomer was separated and purified in the same manner as in Example 2 except that acetic acid was not used.

The weight and analysis values of the obtained solid part and soluble part are as shown in Table 2, and the yield of the solid part is small as compared with Example 2, and especially the components of n = 1 and n = 2. It turns out that there are few.

Comparative Example 3 A sulfone oligomer was separated and purified in the same manner as in Example 2 except that 0.12N hydrochloric acid was used instead of acetic acid and methanol.

The weight and analysis values of the obtained solid part and soluble part are as shown in Table 2. Compared with Example 2, the solid part contains CH as a reaction by-product and BA as a raw material. I know that

Example 3 Instead of acetic acid and methanol, 10 ml of nitric acid and ethanol 1.
The sulfone oligomer was separated and purified in the same manner as in Example 2 except that 4 was used.

The weight of the obtained solid part and the soluble part and the analytical values were as shown in Table 2.

Example 4 A sulfone oligomer was separated and purified in the same manner as in Example 2 except that 100 ml of nitric acid and 1.6 of isopropanol were used instead of acetic acid and methanol.

The weight of the obtained solid part and the soluble part and the analytical values were as shown in Table 2.

Reference Example 3 23.84 g of bis (4-hydroxyphenyl) sulfide instead of 2,2-bis (4-hydroxyphenyl) propane
The same operation as in Reference Example 2 was performed except that (0.1092 mol) was used to obtain a sulfone oligomer solution.

Example 5 The solution obtained in Reference Example 3 was slowly added to a mixed solution of 10 ml of hydrochloric acid and methanol 1 which was subjected to intensive stirring by inversion, and the precipitated solid matter was filtered to separate from the filtrate.

The solid was washed with 0.1N hydrochloric acid water 1 and water 2 with stirring twice, and then dried at 110 ° C. for 6 hours to obtain a solid part having the composition shown in Table 3.

Reference Example 4 A sulfone oligomer solution was obtained by performing the same operation as in Reference Example 2 using 20,34 g (0.1092 mol) of 4,4′-dihydroxydiphenyl instead of 2,2-bis (4-hydroxyphenyl) propane. .

Example 6 The solution obtained in Reference Example 4 was used and the same procedure as in Example 5 was carried out. As a result, a solid part having the composition shown in Table 3 was obtained.

Reference Example 5 A sulfone oligomer solution was obtained in the same manner as in Reference Example 2 except that 12.02 g (0.1092 mol) of 1,3-dihydroxybenzene was used instead of 2,2-bis (4-hydroxyphenyl) propane. It was

Example 7 Using the solution obtained in Reference Example 5 and carrying out in the same manner as in Example 5, the solid part having the composition shown in Table 3 was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Ukita 6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Inside Mitsubishi Gas Chemical Co., Ltd. Headquarters Research Laboratory (72) Noriaki Honda Honda 6-1, Shinjuku, Katsushika-ku, Tokyo No. 1 Mitsubishi Gas Chemical Co., Ltd. Headquarters Research Center

Claims (8)

[Claims] 1. A polar solvent solution of a sulfone oligomer represented by the general formula [I] obtained by heating 4,4′-dichlorodiphenyl sulfone and an alkali salt of a bifunctional phenol in a polar solvent. Acid and carbon number 1-5
The method for purifying and separating a sulfone oligomer represented by the general formula [II], characterized in that the precipitated solid content is separated by mixing with the monohydric alcohol (In the formula [I], M is the same or different and is a hydrogen atom, a sodium atom or a potassium atom, and R is the same or different, Indicates an average degree of polymerization of 4 to 15. ) (In the formula [II], R and R are the same as those in the formula [I].) 2. The method according to claim 1, wherein M in the general formula [I] is the same or different and is a hydrogen atom or a sodium atom, and is 5 to 13. 3. R in general formula [I] and general formula [II] is The aromatic polyester according to claim (1) 4. The method according to claim 1, wherein the polar solvent is dimethyl sulfoxide, sulfolane, dimethylacetamide, dimethylformamide, N-methylpyrrolidone or N-methylcaprolactam. 5. The method according to claim 1, wherein the monohydric alcohol is methanol, ethanol, normal propanol or isopropanol. 6. The method according to claim 1, wherein the amount of the monohydric alcohol used is 2 to 20 times the volume of the polar solvent used. 7. The method according to claim 1, wherein the acid is hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid or acetic acid. 8. The method according to claim 1, wherein the amount of the acid used is 5% by volume of the amount of the 2-fold mole of the sulfone oligomer to the amount of the monohydric alcohol used.