JPH11322845A - Polyvinylbenzoic acid and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyvinylbenzoic acid by a simple radical polymerization process without requiring a complicated process such as pretreatment and to obtain an industrially useful high-molecular weight polyvinyl benzoic acid. SOLUTION: In this method for producing a polyvinylbenzoic acid by polymerizing vinylbenzoic acid by using a photosensitizer, vinylbenzoic acid is intercalated in an inorganic laminar compound in a water medium and is polymerized by irradiation with light rays. This polyvinylbenzoic acid is obtained by the method and has 3,000-300,000 calculated as polystyrene number-average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to polyvinyl benzoic acid and a method for producing the same. More specifically, the present invention relates to a method for producing polyvinyl benzoic acid by a simple radical polymerization process without requiring a complicated operation such as pretreatment, and a polyvinyl benzoic acid having a high degree of polymerization obtained by the method.

[0002]

2. Description of the Related Art Polyvinyl benzoic acid is a styrene-based polymer having a carboxyl group in the molecule, and is used for various industrial applications as a unique resin having both properties of a thermoplastic resin and a functional resin. It is also useful as a raw material for synthesizing a new functional resin by substituting a carboxyl group with another functional group. Despite such usefulness, it has been conventionally difficult to obtain polyvinyl benzoic acid directly from vinyl benzoic acid. Therefore, after pre-treatment to increase polymerization reactivity, polymerization is carried out to produce polyvinyl benzoic acid. I had no choice. Several such manufacturing methods have been disclosed. For example, JP-A-2-28100
In Japanese Patent Application Laid-Open No. 7-264, after the carboxyl group of vinylbenzoic acid is reacted with a cyclic amine to form a tertiary amide,
JP-A-351610 discloses a method of obtaining polyvinyl benzoic acid by esterification with a bulky substituent, followed by polymerization by a general anionic polymerization method and hydrolysis.

[0003]

However, as described above, since the method involves once converting the carboxyl group of vinyl benzoic acid into an amide group or an ester group, polymerizing the carboxylic acid group, and then hydrolyzing it, the method is very complicated. Met. Also,
Since the polymerization mode in this case is an anionic polymerization method, it is susceptible to the effects of moisture and impurities in the polymerization system, and special precautions are required when performing polymerization. An object of the present invention is to provide a method for producing polyvinyl benzoic acid by a simple radical polymerization process without complicated operations such as pretreatment of a carboxyl group of vinyl benzoic acid as a raw material, and industrially. It is to provide a useful high molecular weight polyvinyl benzoic acid.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on the problems of the above-mentioned conventional method over a long period of time, and have found that vinylbenzoic acid is molecularly oriented in a specific direction between layers of a specific inorganic layered compound. The inventors have found that vinylbenzoic acid can be radically polymerized by light irradiation using a photosensitizer after the adsorption, and the present invention has been completed. That is, the first invention of the present invention relates to a method for producing polyvinyl benzoic acid by polymerizing vinyl benzoic acid using a photosensitizer, wherein polyvinyl benzoic acid is intercalated (inserted) into an inorganic layered compound in an aqueous medium. And then polymerizing by irradiation with light. The second invention is the method for producing polyvinyl benzoic acid according to the first invention, wherein the inorganic layered compound is a synthetic hydrotalcite chloride ion exchanger. A third invention is the method for producing polyvinyl benzoic acid according to the first or second invention, wherein the photosensitizer is 4-benzoylbenzoic acid. A fourth invention is a polyvinyl benzoic acid obtained by the method for producing polyvinyl benzoic acid according to any one of the first, second or third inventions, wherein the polyvinyl benzoic acid has a number average molecular weight of 5,000 to 100,000 in terms of polystyrene. Is an acid.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a specific inorganic layered compound is used as a host in an aqueous medium before the polymer is irradiated with light using a photosensitizer to polymerize vinylbenzoic acid. A photopolymerization reaction is carried out by intercalating vinylbenzoic acid or its deprotonated carboxylate anion compound (hereinafter abbreviated as vinylbenzoic acid or the like) as a guest molecule and then irradiating light.

The aqueous medium used in the present invention is water alone or an aqueous solution containing a water-soluble organic solvent, but water alone is most preferred. The aqueous medium is preferably alkaline in order to increase the solubility of the photosensitizer and vinylbenzoic acid used in the present invention, and the specific aqueous solution preferably has a pH of 8 to 10. As the alkalizing agent for making it alkaline, all commonly used alkalizing agents can be used, and sodium hydroxide and potassium hydroxide are particularly preferred. Further, as the water-soluble organic solvent,
For example, lower alcohols such as methanol and ethanol,
Examples thereof include lower ketone compounds such as acetone and methyl ethyl ketone, and dioxane.

The amount of vinyl benzoic acid used in the present invention is not particularly limited as long as it is not more than the solubility of vinyl benzoic acid in an aqueous medium.
0.1 to 10% by weight, more preferably 0.1 to 10% by weight.
The range is from 02 to 5% by weight.

The inorganic layer compound used in the present invention includes:
Any material can be used as long as it can adsorb the carboxyl group or carboxylate anion group of vinylbenzoic acid in the layer and can orient vinylbenzoic acid or the like in a specific direction. Specific examples of the inorganic layered compound include anion exchangers of synthetic hydrotalcite, that is, chloride ion exchangers, nitrate ion exchangers, and sulfite ion exchangers. Among them, a chloride ion exchange product of synthetic hydrotalcite is preferable because vinylbenzoic acid and the like can be relatively easily taken into the interlayer.

Next, the intercalation of vinyl benzoic acid and the like into the inorganic layer compound will be described. In the synthetic hydrotalcite, the layered skeleton itself has a positive charge, and the positive charge is an inorganic anion such as a chloride ion, a nitrate ion, or a sulfite ion captured between layers (hereinafter, referred to as an interlayer inorganic anion). ), And at the same time forms a laminated structure in which the layered frameworks are joined together by a weak Coulomb force. Intercalation of vinyl benzoic acid or the like proceeds by ion exchange between the interlayer inorganic anion and vinyl benzoic acid or the like. The intercalated vinyl benzoic acid or the like is in a state where the benzene ring of each molecule stands vertically between the layered skeletons 1 and 2 in the inorganic layered compound as shown conceptually in FIG. And the benzene rings between the molecules are arranged in parallel. That is, each molecule directs the vinyl group, which is the non-polar group 4, toward the inside of the layer, and the carboxyl group or carboxylate anion group, which is one of the polar groups 3, has the layered skeleton 1, 2
Are adsorbed toward the surface side, and the molecules adjacent thereto are in an antiparallel arrangement in which the molecules are alternately connected to the layered skeleton 2 facing the layered skeleton 1.

As the photosensitizer used in the present invention, any photosensitizer that can initiate a photopolymerization reaction upon irradiation with light to produce polyvinyl benzoic acid can be used, and preferably, benzoyl benzoic acid and benzene ring are used. Is a benzoic acid having a substituent containing a carbonyl group. Specific examples include, for example, 4-benzoylbenzoic acid, 4-acetylbenzoic acid and the like. Among them, 4-benzoylbenzoic acid is particularly preferred. The amount of the photosensitizer to be added is usually in the range of 1/100 to 10 times, preferably in the range of 1/10 to 2 times, in molar ratio to vinyl benzoic acid. If the added amount of the photosensitizer is less than 1/100, the polymerization rate will be slow and a large amount of cyclobutane-type dimer in which two molecules of vinylbenzoic acid are cyclized will be produced as a by-product. It is not preferable because the rate decreases. On the other hand, when the addition amount of the photosensitizer exceeds 10 times, it is not preferable because the molecular weight of the obtained polymer is extremely reduced.

The order of addition of the inorganic layered compound, photosensitizer and vinylbenzoic acid to the reaction medium used in the present invention may be any order as long as the adsorption to the inorganic layered compound is fast, and is not particularly limited. However, usually, a method in which the photosensitizer and vinylbenzoic acid are adsorbed and orientated in the inorganic layered compound in advance is a preferable method for increasing the polymer yield. In addition, a method in which the substrate is left in a heated state during the adsorption orientation is a preferable method, and the heating temperature is usually 20 to 90 ° C, preferably 40 to 80 ° C. Also, the leaving time is usually 1
-100 hours, preferably 12-60 hours.

When the photopolymerization reaction is carried out, ultraviolet light having a wavelength of 200 to 400 nm, which is the absorption wavelength of the photosensitizer, is usually used. However, the wavelength of the irradiated light is 30
When it is 0 nm or less, a cyclobutane-type dimer is easily produced as a by-product due to direct light absorption of vinylbenzoic acid.
30-380 nm is particularly preferred. Examples of the light source include a high-pressure mercury lamp, a metal halide lamp, and a xenon lamp. The irradiation time varies depending on the light source used, the type of photosensitizer and the amount used, and cannot be unconditionally specified, but is preferably 1 to 24 hours, more preferably 3 to 15 hours. The polymerization temperature is not higher than the boiling point of the reaction solvent, and is usually 0 to 100 ° C, preferably 10 to 50 ° C.
° C. The number average molecular weight of the polyvinyl benzoic acid obtained by the method of the present invention is usually from 3,000 to 300,000, preferably from 5,000 to 100,000 in terms of polystyrene.

[0013]

According to the production method of the present invention, firstly, it is possible to produce polyvinyl benzoic acid by a simple radical polymerization process without complicated operations such as pretreatment. Secondly, industrially useful high molecular weight polyvinyl benzoic acid can be obtained.

[0014]

The present invention will be described below in more detail with reference to examples and comparative examples. The abbreviations for by-products are as follows. syn-HH: syn-1,2-bis (4-carboxyphenyl) cyclobutane anti-HH: anti-1,2-bis (4-carboxyphenyl) cyclobutane syn-HT: syn-1,3-bis (4- (Carboxyphenyl) cyclobutane The analysis was performed by the following method.

(Measurement of conversion, by-product formation amount and isomer ratio) After the product is methylesterified, it is subjected to high performance liquid chromatography (hereinafter abbreviated as HPLC) using an adsorption column using dichloromethane as a mobile phase. The reaction conversion of vinylbenzoic acid, the amount of by-product cyclobutane-type dimer formed, and the isomer ratio were determined.

(Measurement of yield and number average molecular weight of polyvinyl benzoate) After methyl esterification of the product, LC90 (manufactured by Nippon Kagaku Kogyo Co., Ltd.)
The product was analyzed by a type 8 gel filtration chromatograph (hereinafter abbreviated as GPC; column: JAIGEL-2H and 3H) to calculate the amount of poly (vinyl benzoate) generated, and further generated from a calibration curve using standard polystyrene as a standard. The number average molecular weight of the product was calculated as a value in terms of polystyrene.

(Confirmation of the cyclobutane type dimer of methyl ester of polyvinyl benzoic acid and methyl vinyl benzoate) After methyl esterification of the product, chloroform was used as a mobile phase and LC908 type preparative GPC manufactured by JASCO Corporation. (Column: JAIGEL-1H and 2H)
And the poly (vinyl benzoate) and the cyclobutane type dimer were isolated. Next, after diluting each with a heavy chloroform solvent, it was confirmed from the nuclear magnetic resonance spectrum (hereinafter abbreviated as NMR) that the product was a methyl ester of polyvinyl benzoic acid and a cyclobutane type dimer of methyl vinyl benzoate. .

Example 1 (Synthesis of Synthetic Hydrotalcite Chloride Ion Exchange Product) 5
In a 00 ml round bottom flask, 100 g of water, 8.05 g (0.333 mol) of aluminum chloride hexahydrate and 13.6 g (0.667 mol) of magnesium chloride hexahydrate were dissolved. Thereafter, 100 g of water, 8.00 g (2 mol) of sodium hydroxide and 3.89 g of sodium carbonate were added thereto.
(0.367 mol) was added dropwise with stirring at 60 ° C. while stirring, and the alkaline (p
H: 10.5). After the addition, the mixture was left for 2 hours.
Next, the generated white precipitate of hydrotalcite was separated by centrifugation, and sufficiently washed with ion-exchanged water. The obtained synthetic hydrotalcite was dispersed in 100 ml of water, and adjusted to acidic (pH: 3.0) with 1N hydrochloric acid. Further, in order to sufficiently replace the carbonate ions between the layers with chloride ions, the mixed solution is kept in a dispersed state at 60 ° C. for 12 hours.
After stirring for an hour, the mixture was separated by centrifugation. Further, it was sufficiently washed with ion-exchanged water and air-dried to obtain a synthetic hydrotalcite chloride ion-exchange product.

(Production of polyvinyl benzoic acid) In a 30 ml beaker, sodium hydroxide 4 mg, water 10 g, 4-vinyl benzoic acid 14.7 mg (9.9 mmol), 4-benzoyl benzoic acid 0.2 mg (0.1 mmol) 28.6 m) and the above-mentioned synthetic hydrotalcite chloride ion exchanger
g (10 mmol) and 300 min at 70 ° C. for 20 minutes.
Stirred at RPM. Stop stirring, leave at 70 ° C overnight,
Vinyl benzoic acid and 4-benzoyl benzoic acid were sufficiently adsorbed on the synthetic hydrotalcite chloride ion exchanger. After that, it was placed in a light irradiation tube, and was sufficiently replaced with argon gas by a bubbling method, and then sealed. Polyvinyl benzoic acid was produced by irradiating light having a wavelength of 330 nm or more for 6 hours using a 300 W high-pressure mercury lamp and a chemical filter. After irradiation, hydrochloric acid was added to decompose the clay, and the precipitated precipitate was separated by filtration, methylesterified with diazomethane, and then analyzed by HPLC, GPC and NMR. As a result of analysis, the conversion of vinylbenzoic acid was 64%. The yield of polyvinyl benzoic acid was 43%, and the number average molecular weight was 40,000 in terms of polystyrene. The total amount of by-products is 21%, and the isomer ratio is sy.
n-HH: anti-HH: syn-HT = 81: 1
4: 5.

Example 2 In Example 1, the amount of 4-vinylbenzoic acid was changed to 13.3.
mg (9 mM) and the amount of 4-benzoylbenzoic acid was changed to 2.3 mg (1 mM) to produce and analyze polyvinyl benzoic acid according to Example 1. As a result, the conversion of vinylbenzoic acid was 90%. The yield of polyvinyl benzoic acid was 50%, and the number average molecular weight was 20,000 in terms of polystyrene. The total amount of by-products produced was 40% and the isomer ratio was syn
-HH: anti-HH: syn-HT = 83: 13:
It was 4.

Example 3 In Example 1, the amount of 4-vinylbenzoic acid was 7.4 m
g (5 mM) and the amount of 4-benzoylbenzoic acid is 1
A polyvinyl benzoic acid was produced and analyzed according to Example 1, except that the amount was changed to 1.3 mg (5 mM). As a result, the conversion of vinylbenzoic acid was 100%. The yield of polyvinyl benzoic acid was 100%, and its number average molecular weight was 17000 in terms of polystyrene. No by-products of the cyclobutane type dimer were found.

Comparative Example 1 Example 1 was repeated except that no synthetic hydrotalcite chloride ion exchanger was used as the inorganic layered compound.
After the production of polyvinyl benzoic acid according to the above, the reaction product was taken out of the reaction system and analyzed. As a result, neither a polymer nor a cyclobutane type dimer product was confirmed, and 9
9.2% of vinylbenzoic acid was recovered, indicating that the reaction had not progressed.

Comparative Example 2 A polyvinyl benzoic acid was produced in the same manner as in Example 1 except that 4-benzoylbenzoic acid was not used, and then the reaction product was taken out of the reaction system and analyzed. As a result, no polymer or cyclobutane type dimer product was confirmed, and 99.7% of vinylbenzoic acid was recovered, indicating that the reaction hardly proceeded.

[Brief description of the drawings]

FIG. 1 is a conceptual model diagram showing a state in which vinyl benzoic acid is intercalated into an inorganic layered compound.

[Explanation of symbols]

 1. 1. Layered skeleton 1 Layered skeleton 2 3. Polar group 4. Non-polar group

Claims (4)

[Claims] 1. A method for producing polyvinyl benzoic acid by polymerizing vinyl benzoic acid using a photosensitizer, wherein vinyl benzoic acid in an aqueous medium is intercalated into an inorganic layered compound, and then irradiated with light to carry out polymerization. A method for producing polyvinyl benzoic acid. 2. The method for producing polyvinyl benzoic acid according to claim 1, wherein the inorganic layered compound is a synthetic hydrotalcite chloride ion exchanger. 3. The method for producing polyvinyl benzoic acid according to claim 1, wherein the photosensitizer is 4-benzoyl benzoic acid. 4. A polyvinyl benzoic acid obtained by the method for producing polyvinyl benzoic acid according to claim 1, wherein the number average molecular weight is 30 in terms of polystyrene.
Polyvinyl benzoic acid having a molecular weight of 00 to 300,000.