JP3475434B2 - How to introduce azo groups - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for introducing an azo group having a radical polymerization activity into various compounds. The obtained azo compound is particularly useful, for example, for producing a block copolymer by a radical polymerization method. 2. Description of the Related Art Various block copolymers and graft copolymers in which different polymers are molecularly complexed have been synthesized for the purpose of enhancing the functionality and performance of polymer materials. As a method for producing a block copolymer, a living anionic polymerization method is known. However, the living anionic polymerization method requires that a monomer or a solvent to be used has a high purity, and the polymerization is carried out at an extremely low temperature. In many cases, it is not always suitable as an industrial production method. Recently, attempts have been made to synthesize block copolymers by a radical polymerization method which is relatively easy to handle. [0005] As one of the methods for synthesizing a block copolymer by a radical polymerization method, a polymer containing a polymerization-active azo group is synthesized, and this is used as a polymerization initiator to polymerize a vinyl monomer. There is a way. As a method for synthesizing such a polymerization-active azo group-containing polymer, a method of subjecting an azo compound having a carboxylic acid group to a condensation reaction with a compound having an amino group or a hydroxyl group, or a method of synthesizing an azo compound having an amino group or a hydroxyl group is used. A method is known in which a compound and a compound having a carboxylic acid group are subjected to a condensation reaction. The condensation reaction is usually carried out at a high temperature or under reduced pressure. However, when an azo group having polymerization activity is introduced by the condensation reaction, the reaction is carried out under mild conditions to suppress the decomposition of the azo group. There is a need to do. For example, Polymer Collection, 33
Vol., P. 131 (1976), shows a method of reacting 4,4′-azobis (4-cyanopentanoic acid) by acid chloride. However, the acid chloride of 4,4'-azobis (4-cyanopentanoic acid) has problems that the yield is low and that the obtained acid chloride is extremely poor in stability and difficult to store. . As a method not via acid chloride, 1
-Methyl-2-chloropyridinium iodide is reacted as a condensing agent by a method described in Chemistr.
yExpress, Volume 2, page 33. This method has the advantage that it can be synthesized in high yield, but since the 1-methyl-2-chloropyridinium iodide is colored, the resulting azo group-containing compound is colored, and When the polymerization is carried out using such an azo group-containing compound as a polymerization initiator, there is a problem that the hue of the obtained polymer deteriorates. The object of the present invention is to introduce an azo group exhibiting polymerization activity into various compounds under mild conditions which are easy to handle and do not alter the azo group, and which are highly efficient. It is intended to provide a method characterized in that the reaction is performed in a high yield and without coloring during the reaction. Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by using 1,1′-carbonyldiimidazole as a condensing agent to cause a condensation reaction, The inventors have found that the above objects can be achieved, and have completed the present invention. That is, the present invention relates to a method for introducing an azo group into a polymer compound or silica gel by subjecting an azo compound having a carboxylic acid group to a condensation reaction with a polymer compound having an amino group or a hydroxyl group or silica gel having an amino group . And 1,1,1'-carbonyldiimidazole as a condensing agent. The azo compound having a carboxylic acid group includes 2,2′-azobis (2-cyanopropanoic acid),
3,3′-azobis (3-cyanobutanoic acid), 4,4 ′
-Azobis (4-cyanopentanoic acid), 2,2'-azobis (2-methylpropanoic acid), 1-((1-cyano-
1-methylethyl) azo) formic acid and the like. In the present invention, an azo group-introduced polymer compound having an amino group or a hydroxyl group, or an amino group
Silica gel having is not particularly limited, the number in one molecule of these functional groups may be one or more. Also, when comparing the amino group and the hydroxyl group among these polymer compounds,
An amino group is more reactive and advantageous. [0018] High frequency having an amino group introduced an azo group
Examples of the child compound include amino-modified polydimethylsiloxane, amino-modified polyethylene glycol, amino-modified polypropylene glycol, amino-modified polytetramethylene glycol, amino-modified acrylonitrile-butadiene rubber (NBR), and amino-terminal polystyrene and polyamide such as polyamide. Examples include a polymer compound having a group, and silica gel having an amino group. Examples of the high molecular compound having a hydroxyl group into which an azo group is introduced include hydroxyl groups such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyvinyl alcohol, cellulose, hydroxyl-modified polydimethylsiloxane, and hydroxyl-modified polybutadiene. Having a high molecular compound. The reaction of the present invention is usually carried out in a solvent. Examples of the solvent include ethers such as diethyl ether, tetrahydrofuran, dimethoxyethane and dioxane.
Halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and trichloroethane; hydrocarbons such as hexane, petroleum ether, petroleum benzene, benzene, toluene, and xylene; acetonitrile;
Examples thereof include N-dimethylformamide and dimethyl sulfoxide, and one or more of these can be used. In the present invention, the ratio of the azo compound to the compound into which the azo group is introduced is not particularly limited and is appropriately determined depending on the intended product. To react one mole of a compound having an amino group or a hydroxyl group, one mole of 1,
1'-carbonyldiimidazole is required. The amount of the solvent to be used is appropriately determined according to the solubility of the starting compound or the compound to be used, the viscosity of the reaction solution, and the like. The reaction temperature is desirably as low as possible in order to suppress the decomposition of the azo group. However, since the reaction rate becomes slower as the temperature decreases, the rate of decomposition of the azo group of the azo compound used is taken into consideration. Is determined as appropriate.
Specifically, the temperature is usually about −20 to 60 ° C., the reaction may be performed at a constant temperature, or the temperature may be increased or decreased stepwise. The reaction time is not particularly limited, but is usually 0.1.
It is about 1 to 48 hours, preferably 0.1 to 5 hours. In the reaction of the present invention, the product is obtained as a mixture with imidazole derived from 1,1'-carbonyldiimidazole, and the imidazole can be removed by extraction with water, alcohols, ethers and the like. . EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples. The analysis was performed by the following method. The IR measurement was performed with an infrared spectrophotometer (IR-460, Shimadzu Corporation). The molecular weight of the produced azo group-containing compound was measured by GPC (Tosoh Corporation, HLC-8).
02A) in terms of polystyrene. The coloring degree of the produced azo group-containing compound is as follows:
The light transmittance was measured using a double beam spectrophotometer (Hitachi, Ltd., Model 220), by dissolving the azo group-containing compound in tetrahydrofuran (concentration: 1 g / l) and using a 1 cm thick cell. As a guide. Example 1 A 300 ml three-necked round bottom flask was charged with 5.6 g of dried 4,4'-azobis (4-cyanopentanoic acid) and dispersed in 140 ml of dichloromethane. This is 1,1 '
The reaction occurred when 7.1 g of -carbonyldiimidazole was added, and carbon dioxide was generated. After stirring for 1 hour at room temperature,
Amino-modified polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd., X-22-161B, molecular weight about 3000) 60
g was added after drying and reacted at room temperature for 5 hours. As the reaction progressed, the reaction system gradually changed from a heterogeneous system to a homogeneous system, and after 4 hours, became a transparent and uniform solution (almost colorless). After completion of the reaction, the by-product imidazole was removed by extraction with water, and then the solvent was distilled off under reduced pressure at room temperature to obtain 64 g of an almost colorless viscous substance (98% yield). The obtained compound was 1650 c by IR measurement.
The presence of the amide absorption peak at m ^-1 and the increase in molecular weight (Mw) to 120,000 confirmed that the desired reaction had proceeded. The obtained compound was almost colorless, and the light transmittance at 420 nm of a tetrahydrofuran solution (concentration: 1 g / l) was 99.7%. Example 2 5.6 g of 4,4'-azobis (4-cyanopentanoic acid) was charged into a 300 ml three-necked round bottom flask, and dispersed in 140 ml of dichloromethane. To this, 7.1 g of 1,1'-carbonyldiimidazole was added, and the mixture was stirred at room temperature for 1 hour. Then, carbinol-modified polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd., KF-6001, molecular weight: about 15)
00) was added and reacted at room temperature for 24 hours. After completion of the reaction, insolubles were filtered off, the filtrate was washed with water, and the solvent was distilled off at room temperature under reduced pressure to obtain 12 g of a nearly colorless viscous oil (yield: 29%). The obtained compound was 1740 c by IR measurement.
The presence of the ester absorption peak at m ^-1 and the increase in molecular weight (Mw) to 14000 confirmed that the desired reaction had proceeded. The obtained compound was almost colorless, and the light transmittance at 420 nm of a tetrahydrofuran solution (concentration: 1 g / l) was 99.8%. Example 3 2.2 g of 4,4'-azobis (4-cyanopentanoic acid) was charged into a 300 ml three-necked round bottom flask and dispersed in 140 ml of dichloromethane. 2.8 g of 1,1′-carbonyldiimidazole was added thereto, and the mixture was stirred at room temperature for 1 hour. Then, 60 g of amino-modified polyethylene glycol (Kawaken Fine Chemical Co., Ltd., PEO amine 6000, molecular weight: about 7500) was added, The reaction was performed for 5 hours.
After completion of the reaction, the by-product imidazole was removed by extraction with water, and the solvent was distilled off under reduced pressure at room temperature to obtain 60 g of an almost colorless solid (yield 97%). The obtained compound was 1650 c by IR measurement.
The presence of the amide absorption peak at m ^-1 and the increase in the molecular weight (Mw) to 130,000 confirmed that the desired reaction had progressed. 4 of a solution of the obtained compound in tetrahydrofuran (concentration: 1 g / l)
The light transmittance at 20 nm was 99%. Example 4 5.6 g of 4,4'-azobis (4-cyanopentanoic acid) was charged into a 300 ml three-necked round bottom flask, and dispersed in 100 ml of dichloromethane. To this, 7.1 g of 1,1'-carbonyldiimidazole was added, and the mixture was stirred at room temperature for 1 hour. Then, amino-modified NBR (Ube Industries, Ltd., HY
CAR ATBN 1300 × 16, molecular weight about 350
0) 36 g was added and reacted at room temperature for 5 hours. After completion of the reaction, the by-product imidazole is extracted with water and removed.
The solvent was distilled off under reduced pressure at room temperature to obtain 38 g of a yellow viscous substance (yield: 93%). The obtained compound was 1650 c by IR measurement.
The presence of the amide absorption peak at m ^-1 and the increase in molecular weight (Mw) to 70,000 confirmed that the desired reaction had proceeded. Example 5 A 2.8 g of 4,4'-azobis (4-cyanopentanoic acid) was charged into a 50 ml eggplant-shaped flask, dissolved in 20 ml of N, N-dimethylformamide, and dissolved in 1,1'-carbonyldiimidazole 3 Then, the mixture was stirred at room temperature. 1
After reacting for an hour, the stirring is stopped, and silica gel with amino group bonded thereto (Wakosil 5N, Wako Pure Chemical Industries, Ltd.)
H ₂ ) was added and reacted at room temperature for 24 hours. After completion of the reaction, the silica gel was washed with various solvents and purified. When the silica gel after the reaction was subjected to IR measurement, the bond was confirmed by the presence of an amide absorption peak at 1650 cm ^-1 . Comparative Example 1 A 300 ml three-necked round bottom flask was charged with 137 m of thionyl chloride.
4,4 ′ dried with diphosphorus pentoxide after ice cooling.
48 g of -azobis (4-cyanopentanoic acid) were added. After the addition was completed, the mixture was heated to 35 ° C. to react. After 10 hours, when a yellow homogeneous solution was obtained, excess thionyl chloride was distilled off under reduced pressure. Chloroform (purified by distillation after removing ethyl alcohol as a stabilizer by washing with water)
To obtain 10.3 g of needle-like crystals (yield 19%). Although the obtained 4,4'-azobis (4-cyanopentanoic acid chloride) was stored in a desiccator, generation of hydrochloric acid gas was recognized, and it was confirmed that the decomposition reaction was in progress. . Comparative Example 2 5.6 g of dried 4,4'-azobis (4-cyanopentanoic acid) was placed in a 300 ml three-necked round bottom flask and dispersed in 140 ml of dichloromethane. When 10.2 g of 1-methyl-2-chloropyridinium iodide and 4.05 g of triethylamine were added thereto, a yellow suspension was obtained. After stirring for 1 hour, the yellow suspension was added to an amino-modified polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd., X-22-
161B) and 4.05 g of triethylamine were added and reacted at room temperature for 5 hours. After completion of the reaction, by-products were extracted and removed with water, and the solvent was distilled off under reduced pressure at room temperature to obtain 63 g of an orange viscous oily target (yield 97%). The production of the target substance was confirmed by IR measurement at 1650.
Performed from the presence of an amide absorption peak at cm ⁻¹ ,
The molecular weight (Mw) of the product was 40,000.
The obtained azo group-containing compound is colored orange, and its compound in a tetrahydrofuran solution (concentration: 1 g / l) is 42%.
The light transmittance at 0 nm was 55%. According to the present invention, various azo compounds having polymerization activity can be easily synthesized at a high yield with little coloring during the reaction.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C07C 245/00 C07C 245/00 255/66 255/66 (56) References JP-A-2-218653 (JP, A) JP-A-1-250343 (JP, A) JP-A-2-3635 (JP, A) JP-A-62-129216 (JP, A) JP-A-2-229873 (JP, A) JP-A-3-182507 (JP, A) JP-A-5-32411 (JP, A) JP-B-55-34162 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 8/30 C01B 33 / 18 C08G 65/333 C08G 77/388 C08G 85/00 C07C 245/00 C07C 255/66

Claims (1)

(57) [Claim 1] An azo compound having a carboxylic acid group is converted to a polymer compound having an amino group or a hydroxyl group or an amino group.
In a method of introducing a azo group into a polymer compound or silica gel by a condensation reaction with silica gel having
A method for introducing an azo group, wherein 1'-carbonyldiimidazole is used as a condensing agent.