JPH0449846B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a block copolymer having a narrow molecular weight distribution. (Prior art) Conventionally, in condensation polymers such as polyester, it has been extremely difficult to directly produce polymers with a narrow molecular weight distribution, and methods such as fractionation must be used to obtain polymers with uniform molecular weights. Nakatsuta. In addition, in the case of condensation polymers, condensation and decomposition occur simultaneously, resulting in random copolymers, and block copolymers cannot generally be obtained. As a result of various studies aimed at producing a block copolymer with a narrow molecular weight distribution, the present inventors discovered a catalyst for producing an epoxide homopolymer (Die
Makromolekulare Chemie, 182 (4), 1073−
9 (1981)) It was discovered that the combination of an organic quaternary salt as a catalyst in addition to an aluminum porphyrin complex is suitable for the above purpose, and the present invention was thus achieved. (Objective of the Invention) An object of the present invention is to provide a method for producing a block copolymer having a narrow molecular weight distribution. (Structure of the Invention) The present invention involves producing a polyester by reacting an acid anhydride with an epoxide using an aluminum porphyrin complex and an organic quaternary salt as catalysts, and then reacting the epoxide or the epoxide with the acid anhydride. The present invention relates to a method for producing a block copolymer and a method for producing a block copolymer by reacting the block copolymer with an epoxide or an epoxide and an acid anhydride. The aluminum porphyrin complex used in the first invention is obtained by reacting an organoaluminum compound and porphyrin, and has the structure shown below. Here, X is halogen, alkyl group or alkoxy group, R ₁ is hydrogen or

[Formula], R ₂ is hydrogen, halogen, alkyl group or alkoxy group. Examples include tetraphenylporphinate aluminum chloride, tetraphenylporphinate aluminum methoxide, and tetraphenylporphinate aluminum methyl. This aluminum porphyrin complex is a known compound obtained, for example, by adding approximately equimolar amounts of an organoaluminium compound to porphyrin in an inert gas atmosphere in the presence of a solvent and reacting the mixture at room temperature. In the production of the aluminum porphyrin complex, porphyrin or tetraphenylporphine with a substituted or unsubstituted phenyl group can be used. As the substituent, halogens such as chloride and bromide, alkyl groups such as methyl and ethyl groups, and alkoxy groups such as methoxy and ethoxy groups can be used. Porphine or tetraphenylporphine with a substituted or unsubstituted phenyl group is prepared by a conventional method from, for example, benzaldehyde and pyrrole or benzaldehyde and pyrrole substituted with the corresponding substituents, respectively. As the organoaluminum compound, dialkyl aluminum halides such as diethylaluminum chloride and diethylaluminum bromide, dialkyl aluminum alkoxides such as diethylaluminum methoxide and diethylaluminum ethoxide, and the like can be used. As the catalyst, hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as methylene chloride, chloroform, and dichloroethane can be used. The amount of solvent used can be selected arbitrarily. Examples of organic quaternary salts used in combination with the aluminum porphyrin complex include phosphonium salts such as ethyltriphenylphosphonium bromide and ethyltriphenylphosphonium iodide, and ammonium salts such as tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium acetate. It can be used. In particular, it is preferable to use ethyltriphenylphosphonium bromide. Next, examples of acid anhydrides used in the present invention include phthalic anhydride, tetrahydrophthalic anhydride, tetrabromo phthalic anhydride, and maleic anhydride. These can be used alone or in combination of two or more in the reaction with the epoxide. Epoxides used in the present invention include aliphatic alkylene oxides having a terminal three-membered epoxy group such as ethylene oxide, propylene oxide, 1-butylene oxide, and epichlorohydrin, and three-membered ring epoxy groups such as cyclohexene oxide and cyclopentene oxide. Examples include aromatic alkylene oxides having a three-membered epoxy group such as alicyclic alkylene oxide, styrene oxide, and phenyl glycidyl ether. These can be used alone or in combination of two or more. The polyester in the present invention is produced by adding an aluminum porphyrin complex and an organic quaternary salt to a mixture of an acid anhydride and an epoxide without a solvent or in the presence of a solvent. It is preferable to use nitrogen as the inert gas. As the solvent, methylene chloride, chloroform, dichloroethane, benzene, toluene, dioxane, tetrahydrofuran, etc. can be used, but halogenated hydrocarbons are particularly preferred. The reaction proceeds satisfactorily at room temperature, but can also be heated. Although the ratio of acid anhydride and epoxide is not particularly limited, it is preferable that the acid anhydride and epoxide are equimolar. There is no particular restriction on the ratio of the aluminum porphyrin complex and the organic quaternary salt used, but the organic quaternary salt is usually used in a range of 1/10 to 10 times the mole of the aluminum porphyrin complex. Preferably, approximately equimolar amounts are used. Further, there is no particular restriction on the ratio of epoxide to the aluminum porphyrin complex, but it is preferable to use the epoxide in a range of 10 to 1000 times the mole of the metal porphyrin complex. A polyester obtained by reacting an acid anhydride with an epoxide using an aluminum porphyrin complex arrow and an organic quaternary salt as a catalyst.As the epoxide to be further reacted, the various epoxides described above are used. These can be used alone or in combination of two or more. This reaction between the epoxide and the polyester is carried out by adding the epoxide to the system in which the polyester is prepared and the aluminum porphyrin complex and organic quaternary salt are present. The reaction proceeds satisfactorily at room temperature, but can also be heated. The proportion of these epoxides is not particularly limited, but is 10% per mole of aluminum porphyrin complex used in the production of polyester.
It is preferable to use it in a range of 1 to 1000 times the mole. In addition, as the acid anhydride to be reacted with the epoxide as needed in the polyester obtained by reacting the acid anhydride with the epoxide using an aluminum porphyrin complex and an organic quaternary salt as a catalyst, the various acid anhydrides mentioned above may be used. things are used. These acid anhydrides can be used alone or in combination with an epoxide in the reaction. Although there is no particular restriction on the ratio of acid anhydride and epoxide to be reacted with polyester, it is preferable that the acid anhydride and epoxide be equimolar. Furthermore, the reaction of the acid anhydride and the epoxide with the polyester is such that the polyester is produced by adding the acid anhydride and the epoxide into the system in which the aluminum porphyrin complex and the organic quaternary salt are present.
It will be done. The reaction proceeds satisfactorily at room temperature, but can also be heated. In the second invention, the above-mentioned epoxide or the above-mentioned epoxide and an acid anhydride are further added to the system containing the block copolymer thus obtained, the aluminum porphyrin complex, and the organic quaternary salt under the above-mentioned conditions. By reacting, more block copolymers can be obtained. The system containing the block copolymer obtained by the second invention, the aluminum porphyrin complex, and the organic quaternary salt may be further reacted with the above epoxide or the above epoxide and an acid anhydride under the above conditions. can. The block copolymer obtained by the production method of the present invention will be explained using an example in which phthalic anhydride is used as the acid anhydride and propylene oxide or ethylene oxide is used as the epoxide. A polyester represented by the following formula is produced from phthalic anhydride and propylene oxide, When reacting this polyester with propylene oxide, A block copolymer A represented by is obtained, and when this polyester is reacted with ethylene oxide and phthalic anhydride, A block copolymer B having the following formula is obtained. Furthermore, when reacting block copolymer A with propylene oxide, A block copolymer C shown in the formula is obtained, and when block copolymer A is reacted with propylene oxide and phthalic anhydride, A block copolymer D represented by is obtained. When reacting block copolymer B with propylene oxide, When block copolymer E shown by is obtained, and block copolymer B is reacted with propylene oxide and phthalic anhydride, A block copolymer F is obtained. In the above formula, l, m, n, p, q, r, and s are positive integers. (Example) The present invention will be explained below with reference to Examples. Reference Example 1 (Manufacture of aluminum porphyrin complex) 80 ml (84.8 g) of benzaldehyde and 56 ml (53.6 g) of pyrrole were added to propionic acid 3 in a No. 4 flask equipped with a cooling tube, and the mixture was reacted under reflux for 30 minutes. , left for one day and night. After filtering the mixture, it was purified by recrystallization with a methanol-chloroform mixed solvent (1:1 by weight). α, β, γ, δ− obtained in this way
The yield of tetraphenylporphin was 20%. This α, β, γ, δ-tetraphenylporphin 0.61g and diethylaluminum chloride 0.12g
was reacted at room temperature under a nitrogen atmosphere in the presence of 20 ml of methylene chloride solvent, and 20 ml of a catalyst solution containing 0.68 g of porphyrin complex solvent [I] [α, β, γ, δ-tetraphenylporphynate aluminum chloride] was added. I got it. Examples 1-4 Phthalic anhydride and various epoxides shown in Table 1
After dissolving 25 mmol each of (1) in 5 ml of methylene chloride, 20 ml of a methylene chloride solution containing 1 mmol each of the porphyrin complex solvent [I] synthesized in Reference Example 1 and ethyltriphenylphosphonium bromide was added, and under a nitrogen atmosphere, The reaction was carried out at room temperature with stirring to obtain polyester (1). Table 1 shows the molecular weight and molecular weight distribution of the obtained polyester (1). Next, in order to synthesize a block copolymer, a methylene chloride solution containing the polyester (1) was added to 5 ml of a methylene chloride solution containing 25 mmol each of phthalic anhydride and various epoxides (2) shown in Table 1 dissolved in a nitrogen atmosphere. The reaction was carried out under stirring at room temperature. After the reaction was completed, the reaction product was dissolved in chloroform and added dropwise into a large amount of methanol to reprecipitate. The polymer was purified by repeating reprecipitation with chloroform-methanol. The polymer thus obtained is a polyester-b-polyester block copolymer (1) and has the molecular weight and molecular weight distribution shown in Table 1.

【table】

[Table] Example 5 25 mmol of phthalic anhydride and propylene oxide
After dissolving 25 mmol in 5 ml of methylene chloride, 20 ml of a methylene chloride solution containing 1 mmol each of the porphyrin complex catalyst [I] synthesized in Reference Example and ethyltriphenylphosphonium bromide was added, and the reaction was carried out with stirring at room temperature under a nitrogen atmosphere. I went there. After the reaction, the average molecular weight (n) of the obtained polyester (2) was 2100, and the molecular weight distribution (w/
Mn) was 1.15. Next, 100 mmol of propylene oxide was added to this reaction system, and under a nitrogen atmosphere,
The reaction was carried out at room temperature with stirring. Unreacted epoxide and solvent were removed by drying under reduced pressure to obtain a polyester-b-polyether block copolymer (2). The average molecular weight (n) of the block copolymer (2) was 3100, and the molecular weight distribution (w/n) was 1.10. Furthermore, this block copolymer (2) is dissolved in methylene chloride, and 5 ml of a methylene chloride solution containing 25 mmol of phthalic anhydride and 25 mmol of propylene oxide is added thereto. The reaction was carried out under a nitrogen atmosphere at room temperature with stirring. After the reaction was completed, the obtained polymer was a polyester-b-polyester-b-polyester block copolymer (3). This block copolymer (3) had an average molecular weight (n) of 4900 and a molecular weight distribution (w/n) of 1.12. (Effects of the Invention) According to the production method of the present invention, a block copolymer with a narrow molecular weight distribution can be obtained under mild conditions at room temperature.

Claims (1)

[Claims] 1. Producing a polyester by reacting an acid anhydride with an epoxide using an aluminum porphyrin complex and an organic quaternary salt as catalysts, and then reacting the epoxide or the epoxide with the acid anhydride. Characteristic manufacturing method for block copolymers. 2. The method for producing a block copolymer according to claim 1, wherein the aluminum porphyrin complex is tetraphenylborphinate aluminum chloride. 3. The method for producing a block copolymer according to claim 1 or 2, wherein the organic quaternary salt is ethyl triphenylphosphonium bromide. 4. A polyester is produced by reacting an acid anhydride with an epoxide using an aluminum porphyrin complex and an organic quaternary salt as a catalyst, and then a block copolymer is produced by reacting an epoxide or an epoxide with an acid anhydride, and A method for producing a block copolymer, which comprises reacting an epoxide or an epoxide with an acid anhydride.