JPH0610214B2 - New living polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel living polymer of an aromatic vinyl compound.

[Conventional technology]

Anion living polymers of vinyl monomers having a reactive group such as a formyl group or a carboxyl group in the molecule have not been obtained directly because of active hydrogen or carbonyl carbon in the reactive group.

However, for an aromatic vinyl monomer having a formyl group, which is one of the reactive groups, the formyl group in the molecule is converted to a substituent consisting of an imidazolidine skeleton in advance and protected, and then an anionic polymerization initiator acts. By doing so, an anionic living polymer of an aromatic vinyl monomer having a protected formyl group is obtained [Polymer Proceedings, Vol. 34, No. 2, 195 (1985)].

[Problems to be solved by the invention]

Generally, a linear polymer having a formyl group in its side chain such as poly (4-formylstyrene) and polyacrylaldehyde is originally soluble in an organic solvent such as tetrahydrofuran (hereinafter abbreviated as THF), When left to stand, the solubility decreases with time and eventually becomes insoluble in the above organic solvent, and the reactivity when the formyl group in the polymer is converted to another polar group by reacting with a suitable compound. It is known to decline.

The cause of this insolubilization is that a chemical bond is formed between the formyl groups in the side chains of the same polymer molecule or different polymer molecules, and intramolecular or intermolecular crosslinks are formed. Therefore, a linear polymer having a formyl group in the side chain is used as a raw material for synthesizing a new functional polymer in which the reactive formyl group is replaced with another functional group, rather than using itself as a functional polymer. In this case, the side chain formyl group in the polymer, in order to prevent insolubilization or decrease in reactivity due to cross-linking between the formyl groups,
It is desirable to protect with a suitable protecting group until just before use.

The above-mentioned suitable protecting group used for protecting the formyl group is one that can simultaneously satisfy the following two requirements.

The protecting group does not react with the anionic polymerization initiator, and the vinyl monomer having a formyl group protected by the protecting group produces an anionic living polymer.

The protective group in the anionic living polymer obtained above is not removed by the treatment with methanol or the like or the purification treatment by reprecipitation, and can be removed only by the protective group removal treatment with a mineral acid or a base.

The substituent consisting of the imidazolidine skeleton, which is a protecting group of the formyl group described above, satisfies the above requirements, but the resulting living polymer is partially protected by treatment with methanol or polymer purification treatment.
As a result, a phenomenon in which an insoluble portion was formed with time was observed, and the above requirements were not satisfied.

[Object of the Invention]

It is an object of the present invention to synthesize an anionic living polymer of a monomer in which a formyl group of an aromatic vinyl monomer having a formyl group is protected by a protecting group which is not removed under conditions other than the specific treatment. .

[Means for solving problems]

(Summary of the Invention) As a result of intensive studies by the present inventors, as a result of converting the formyl group of an aromatic vinyl monomer into a Schiff base with a 2,6-substituted aniline derivative and protecting it, a Schiff base structure is formed. A living polymer having a repeating unit of an aromatic vinyl monomer is produced, and the Schiff base structure in the living polymer is found to exist stably without being decomposed except for a specific treatment using a mineral acid or a base. Completed the invention.

That is, the present invention has the general formula (In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent the same or different alkyl groups.) A novel living polymer having a number average molecular weight of 500 to 500,000 has a repeating unit. The living polymer is a living polymer in which the repeating unit is an integer of 2 or more.

(Method for producing living polymer) The living polymer of the present invention having a repeating unit of the general formula (I) (hereinafter, referred to as living polymer (I)) has the general formula (In the formula, R ¹ represents a hydrogen atom or a methyl group.) The vinyl monomer (II) represented by the formula (Wherein R ² and R ³ represent the same or different alkyl groups), and the resulting Schiff base of the vinyl monomer is contacted with a 2,6-substituted aniline derivative represented by the following formula in the presence of an anionic polymerization initiator. It can be produced by polymerizing.

Specific examples of the vinyl monomer (II) include 4-formylstyrene and 4-formyl-α-methylstyrene.

R ² and R ^{3 in} the formula of the 2,6-substituted aniline derivative used for protecting the reactive group of the vinyl monomer (II) are methyl, ethyl, n-propyl, iso-propyl and n-butyl. , Iso-butyl, t-butyl and the like, and R ² and R ³ may be the same or different.

The reaction between the vinyl monomer (II) and the 2,6-substituted aniline derivative is usually carried out under heating at 70 to 90 ° C for 1 to 10 hours. The contact between them may be carried out in a solvent or in an atmosphere of an inert gas such as nitrogen gas. Suitable solvents include hydrocarbons such as benzene, toluene and m-xylene, halogenated hydrocarbons such as chloroform, hydrogen tetrachloride and dichloroethane.

Further, in the contact between the both, an acidic catalyst such as rosetoluene sulfonic acid may be added if necessary. The contact ratio of the two is preferably 1 time mol of the 2,6-substituted aniline derivative with respect to the vinyl monomer (II), but may be 1 time mol or more. The amount of acidic catalyst used is usually 0.1 to 10 mol% with respect to the vinyl monomer (II).

By doing so, both are condensed to form an aromatic vinyl compound having a Schiff base structure (hereinafter referred to as the vinyl compound), which is then anionically polymerized in the presence of an anionic polymerization initiator. As a result, the living polymer (I) of the present invention is obtained.

Suitable anionic polymerization initiators used in the present invention include naphthalene sodium salt, naphthalene potassium salt, (α-
Methylstyrene oligomer) disodium salt, (α-methylstyrene oligomer) dipotassium salt, cumyl potassium salt and the like can be mentioned.

The anionic polymerization is carried out at −100 ° C. to room temperature, preferably at a low temperature of −30 ° C. or lower, particularly preferably −50 to
It is carried out at a low temperature of -100 ° C for 0.1 to 24 hours. The polymerization reaction may be carried out without a solvent, but is preferably carried out in the presence of a solvent. Examples of suitable solvents include THF, hexane, toluene, cyclohexane, pentane, benzene and the like, and these may be used as a mixture of two or more kinds. Further, the polymerization system is required to be maintained in an inert gas atmosphere free of water and oxygen that interferes with the polymerization reaction or under reduced pressure, particularly preferably under high vacuum.

The molecular weight of the living polymer (I) can be controlled by changing the ratio of the vinyl compound / anionic polymerization initiator, and the molecular weight can be increased by increasing the ratio.

The living polymer (I) thus obtained is usually about 50
0 to about 500,000, preferably about 2000 to about 200
000, particularly preferably about 5,000 to about 100,000, and a very narrow molecular weight distribution with a weight average molecular weight / number average molecular weight ratio close to 1.

〔The invention's effect〕

The living polymer (I) of the present invention is easily contacted with a mineral acid such as hydrochloric acid or sulfuric acid or a base such as sodium hydroxide or potassium hydroxide to easily decompose the protective Schiff base to regenerate the formyl group. To give a polymer of vinyl monomer (II).

Living polymer (I) according to the present invention, compared to a living polymer using an imidazolinyl group as a protecting group of the formyl group, treatment with methanol, ethanol and the like, the protective group does not come off by purification treatment by reprecipitation in water, etc. The feature is that the protecting group can be removed only by the protecting group removing treatment with a mineral acid or a base.

The polymer obtained by removing the protecting groups thus obtained is useful as a functional polymer having a clear linear structure having no cross-linking between side chain formyl groups, and converting all of its reactive substituents into other polar groups. It can be used as a raw material for synthesizing a new functional polymer.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

〔Example〕

(Polymerizer used for anionic polymerization) The anionic polymerization initiator solution and the monomer solution used for anionic polymerization were frozen, degassed in a high vacuum line, and sealed in an ampoule having a break seal.

The anionic polymerization is an apparatus shown in the drawing in which a flask connected to a high vacuum line is connected to the above ampoule containing a plurality of anionic polymerization initiator solutions and monomer solutions and a branch pipe for taking out the waste anionic polymerization agent solution after cleaning the system. Using
The procedure was as follows.

First, degas the flask 1 by keeping it at 10 ^-5 mmHg for 5 hours,
Seal off from the vacuum line 6 at point A, then break the seal of the ampoule 2 containing one anionic polymerization initiator solution,
The inside of the system including the flask 1 was thoroughly washed, and it was guided to a branch pipe 5, and the branch pipe 5 was closed at point B. Next, flask 1-
Cooled to 78 ° C., broke the seal of ampoule 3 containing the second anionic polymerization initiator solution cooled to −78 ° C., led the anionic polymerization initiator to flask 1 and then −78 ° C.
The cooled monomer was similarly introduced into the flask 1 from the ampoule 4 and reacted for 20 minutes. The resulting polymer was post-treated and then subjected to characterization.

(Synthesis and Identification of N- (4-Vinylbenzylidene) -2,6-diethylphenylamine (abbreviated as BDA, the same applies hereinafter)) 4-formylstyrene was added to the reactor. (Abbreviated as FST. The same shall apply hereinafter.)
-A 0.025% benzene solution of 1 mol% paratoluenesulfonic acid was added to diethylaniline and FST, and the reaction was carried out at the reflux temperature of benzene for 5 hours. The obtained product was distilled under reduced pressure to give N- (4-vinylbenzylidene)-
2,6-diethylphenylamine (abbreviated as BDA, the same applies below) was obtained, Grignard reagent (C ₆ H ₅ CH ₂ MgCl) was further added, and vacuum distillation was performed to obtain purified BDA with a yield of 54%. Obtained.

BDA was analyzed by ¹ H NMR (60 MHz, in CCl ₄ , TMS standard), and the following chemical shift values confirmed that BDA had the following structure.

_{1.10ppm (t; 6H, -CH 2} -CH 3), 2.43p
_{pm (q; 4H, -CH 2} -CH 3), 5.19~5.77
ppm (2d; 2H, J = 11Hz, 18Hz, CH 2 =),
6.53~6.93ppm (m; 3H, N- C 6 H 3), 6.
53 to 6.93 ppm (m; 1H, CH =), 7.35
7.92ppm (m; 4H, N- C 6 H 4 -CH = N-),
_{8.17ppm (s; 1H, C 6} H 4 -CH = N-).

(Synthesis and Identification of Living Polymer of BDA) BDA was polymerized using various anionic polymerization initiators shown in Table 1 in THF at −78 ° C. for 20 minutes.
In each case, the polymerization system exhibited a slightly dark red color specific to the living anion.

The living polymer thus produced is treated with a few drops of methanol, and then reprecipitated in water for purification, whereby the protective Schiff base structure remains poly [N- (4-vinylbenzylidene). -2,6-diethylphenylamine] (abbreviated as PBDA, the same applies hereinafter) was quantitatively obtained.

The results of ¹ H NMR (60 MHz, in CCl ₄ , TMS standard) and IR analysis of PBDA are shown below. ¹ H NMR: 1.00 ppm (s; 6H, —CH ₂ —CH ₃ ),
_{2.03ppm (s; 4H, -CH 2} -CH 3), 0.73
_{~2.70ppm (broad; 2H, -CH 2} -CH-),
_{0.73~2.70ppm (broad; 1H, -CH 2} -CH
-), 6.20 to 7.95 ppm (broad; 3H, = NC)
₆ H ₃ ), 6.20 to 7.95 ppm (broad; 4 H, C ₆ H ₄ −
CH = N -), 8.10ppm ( s; 1H, C 6 H 4 -CH =
N-C ₆ H _3).

IR: 2974 and 2876cm ^-1 (-CH _3), 164
5 cm ^-1 (-CH = N-), 1610 and 1511 cm
^-1 (benzene ring internal skeleton), 830 cm ^-1 763 and 700 cm ^-1 From these analysis results, it was confirmed that PBDA had the following structure and the Schiff base structure as the protective group was not removed at all.

The number average molecular weight of PBDA was measured using VPO (Vapor Pressure Osmometer), and the result of comparing the number average molecular weight calculated from the molar ratio of BDA / anionic polymerization initiator was compared.
Shown in the table. It can be seen that the two agree fairly well.

For PBDA, GPC (Gel Per
As a result of meation chromatography, it was confirmed that the polymer had an extremely narrow molecular weight distribution. From these analysis results, it was proved that the polymer obtained by the anionic polymerization of BDA was a living polymer having a repeating unit of BDA.

PBDA includes THF, benzene, toluene, xylene,
Soluble in ethyl acetate, methyl ethyl ketone, chloroform, carbon tetrachloride, dichloromethane, dioxane, n
-Insoluble in hexane, diethyl ether, ethanol, methanol and water.

(Aging of protective groups in PBDA with time) After the PBDA was allowed to stand in an atmosphere of 20 ° C and a relative humidity of 65% for 10 days, the solubility of the PBDA in the solvent was observed, and no insoluble portion was observed. . As a result of ¹ H NMR analysis and IR analysis of this PBDA, the presence of a formyl group was not recognized, and it was confirmed that the Schiff base structure as a protective group was not removed at all when left standing with time.

(Synthesis and Identification of Poly (4-formylstyrene) (abbreviated as PFST. The same shall apply hereinafter)) PBDA was added to THF1 containing 3.8 ml of 36% hydrochloric acid.
It was dissolved in 00 ml to make a 1.6% solution, and heated at 50 ° C. for 3 hours to decompose and remove the Schiff base, which is a protecting group of the formyl group, to obtain PFST. The PFST was purified by the reprecipitation method and then analyzed using ¹ H NMR and IR to confirm that it had the following structure.

PFST is soluble in THF, methyl ethyl ketone, chloroform, dichloromethane, N, N-dimethylformamide, n-hexane, diethyl ether, cyclohexane, carbon tetrachloride, xylene, toluene, ethyl acetate, benzene, acetone, pyridine, dioxane, It was insoluble in ethanol, methanol and water.

[Comparative Example] (4- [2- (1,3-dimethylimidazolidinyl)]
Synthesis and Identification of Living Polymer of Styrene) A monomer in which a formyl group of a styrene monomer having a formyl group is converted into a substituent having an imidazolidine skeleton and protected, that is, 4- [2- (1,3-dimethylimidazolidinyl) ] Styrene (hereinafter abbreviated as pDMIS) is F
Equivalent moles of N, N'-dimethylethylenediamine to ST and FST and 1 mole% of paratoluenesulfonic acid to FST were dissolved in benzene to a concentration of 0.05%. After reacting for a time,
The product was obtained by vacuum distillation. The obtained pDMIS was purified by adding a Grignard reagent (C ₆ H ₅ CH ₂ MgCl) and performing vacuum distillation.

Poly (pDMIS) was quantitatively obtained by anionically polymerizing pDMIS by the same method as in the example and treating the resulting living polymer with methanol. Poly (pDMI
The S) ¹ H NMR and IR analysis, it was confirmed to have the following structure.

Poly (pDMIS) is cyclohexane, diethyl ether,
Soluble in THF, benzene, toluene, xylene, methyl ethyl ketone, ethyl acetate, chloroform, carbon tetrachloride, dioxane, pyridine, N, N-dimethylformamide, n-hexane, acetone, dichloromethane,
It was insoluble in water.

(Aging of protective group in poly (pDMIS) with time) After the poly (pDMIS) was left to stand in an atmosphere of 20 ° C. and a relative humidity of 65% for 10 days, the solubility in the solvent for dissolving poly (pDMIS) was measured. As a result of observation, it was confirmed that an insoluble portion was found and the solubility was lowered. This poly
As a result of ¹ H NMR analysis and IR analysis of (pDMIS), in addition to the peak of the substituent having an imidazolidine skeleton which is a protecting group,
A peak due to the formyl group was recognized.

From these results, it was confirmed that the substituent having an imidazolidine skeleton, which is a protective group, is decomposed when left standing with time to regenerate the formyl group and insolubilize the polymer.

[Brief description of drawings]

The figure is a conceptual diagram of an example of an apparatus for performing anionic polymerization in the present invention. 1 ... Flask, 2, 3 ... Ampoule filled with anionic polymerization initiator solution, 4 ... Ampule filled with monomer solution, 5 ...
Branch pipe, 6 ... vacuum line, 7 ... cock, 8 ... magnet.

Claims (1)

[Claims] 1. A general formula (In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ represent the same or different alkyl groups.) A new living polymer having a number average molecular weight of 500 to 500,000.