JPH06206862A - New azo compound - Google Patents

Abstract

PURPOSE:To provide a new compound useful as a water-soluble radical polymerization initiator and cation polymerization initiator. CONSTITUTION:The compound of the formula (R1 is H, 1-4C alkyl, cyano; R2, R3 are H, halogen, 1-4C alkyl, 1-4C alkoxy; R4, R5 are 1-4C alkyl, benzyl; X is alkylsulfate ion, halide ion, perchlorate ion, etc.; n is 0-5), e.g. 4,4'-azobis[4- cyanopentanoic acid (4-dimethylsulfonylphenyl) ester] methyl sulfate. The compound of the formula is obtained by dehydratively condensing 4- hydroxyphenyldialkyl sulfonium compound with an azobiscarboxylic acid derivative. The compound of the formula can be used as a polymerization initiator to produce a functional polymer having good hydrophilicity and active ester groups on its surface. When a hydrophobic monomer such as styrene is used to synthesize polymer fine particles, the compound of formula acts as a dispersion stabilizer, thereby permitting to perform a soap-free emulsion polymerization.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a novel azo compound. More specifically, the present invention relates to a novel azo compound having characteristics that it can function as a water-soluble radical polymerization initiator or a cationic polymerization initiator.

[0002]

2. Description of the Related Art Conventionally, azo compounds have been mainly used as dyes, foaming agents, polymerization initiators and the like. Especially as a polymerization initiator, accuracy such as decomposition temperature is required,
Here, the decomposition temperature of the azo compound can be adjusted by changing the structure at both ends thereof. When an azo compound is used as a polymerization initiator, it decomposes depending on its action temperature to generate nitrogen gas, and at the same time, the structures at both ends are generated as radical species.

Radical species are bound to both ends of the polymer. That is, both ends of the polymer show the structure of the used initiator. Since many polymers are hydrophobic, various initiators have been developed for the purpose of functionalizing the polymerized polymer.For example, in order to make the surface hydrophilic, an amidino group is used as the initiator and a carboxyl group is used as the terminal. Those derived from groups have been developed. However, they only have the effect of rendering the surface hydrophilic and do not have active reactive groups. In addition, among azo compounds, compounds that simultaneously generate a radical species and a cation species are not known.

[0004]

The azo compound of the present invention is disclosed in Chemical formula 2.

[Chemical 2] (However, R ₁ is hydrogen, a C ₁ -C ₄ alkyl group, or a cyano group, and R ₂ and R ₃ are independent. Hydrogen, halogen, a C ₁ -C ₄ alkyl group or a C ₁ -C ₄ alkoxy group, and R ₄ and R ₅ independently represent a C ₁ -C ₄ alkyl group or a benzyl group. X is alkyl sulfate ion, halogen ion, perchlorate ion, hydrogen sulfate ion, p-
It is one of a toluene sulfonate ion, a hexafluoroantimonate ion, a hexafluorophosphate ion, and a tetrafluoroborate ion. Further, n is 0 or an integer of 5 or less. )

The preferred embodiments of the novel azo compound are 4,4'-azobis [4-cyanopentanoic acid (4-dimethylsulfoniophenyl) ester] methyl sulfate and 4,4'-azobis [4-methyl]. Pentanoic acid (4-dimethylsulfoniophenyl) ester] Methyl sulfate, 4,4'-azobis [4-cyanopentanoic acid (4-diethylsulfoniophenyl) ester] Ethyl sulfate, 2,2'-azobis [2 -Cyanopropionic acid (4-dimethylsulfoniophenyl) ester] methyl sulfate, 4,4'-azobis [4-cyanopentanoic acid (4-methylbenzylsulfoniophenyl) ester] hexafluoroantimonate and the like can be mentioned. .

The azo compound of the present invention is disclosed, for example, in Japanese Patent Laid-Open No.
According to 3-8365, it is synthesized by dehydration condensation of a 4-hydroxyphenyldialkylsulfonium compound and an azobiscarboxylic acid derivative.

[0007]

The novel azo compound of the present invention can be made into a functional polymer having an active ester group on the surface, as well as making the surface of the polymerized polymer hydrophilic by using it as a polymerization initiator. Particularly when synthesizing fine particles using a hydrophobic monomer such as styrene, since the azo compound of the present invention acts as a dispersion stabilizer on the surface of the fine particles,
Soap-free emulsion polymerization can be carried out in water without using a third component such as a dispersion stabilizer.

[0008]

EXAMPLES Examples of the present invention will be shown below, but the scope of the present invention is not limited thereto. Example 1 Synthesis of 4,4'-azobis [4-cyanopentanoic acid (4-dimethylsulfoniophenyl) ester] methyl sulfate 4,4'-azobis (4-cyanopentanoic acid) 4.20
and 5.33 g of 4-hydroxyphenyldimethylsulfonium methylsulfate in 300 ml of acetonitrile in the presence of 6.19 g of dicyclohexylcarbodiimide.
The reaction was carried out at ℃ for 24 hours. After the reaction, the mixture was filtered, and a large excess of ethyl acetate was added to the filtrate, and the precipitated crystal product was taken out by filtration to obtain 7.05 g of white crystals (yield 90.7%). From the following analytical values, it was confirmed to be the target product. Melting point 93 to 95 ° C. IR (KBr) cm −1 1760 1220 760 Elemental analysis C ₃₀ H ₄₀ N ₄ O ₁₂ S ₄ Theoretical value: C: 46.39% Measured value: 45.47% H: 5.15 % 4.97% N: 7.22% 7.38%

Example 2 2,2'-azobis [2-cyanopropionic acid (4-methylbenzylsulfoniophenyl) ester] Synthesis of hexafluoroantimonate 2,2'-azobis (2-cyanopropionic acid) 3 .3
6 g and 4-hydroxyphenylmethylbenzylsulfonium hexafluoroantimonate 9.34 g were reacted in 300 ml of acetonitrile in the presence of 6.19 g of dicyclohexylcarbodiimide at 0 ° C. for 24 hours. After the reaction, the mixture was filtered, and a large excess of ethyl acetate was added to the filtrate, and the precipitated crystal product was taken out by filtration to obtain 9.76 g of white crystals (yield 87.0%). From the following analytical values, it was confirmed to be the target product. Melting point 119 to 122 ° C. IR (KBr) cm-1 1770 1225 760 Elemental analysis C ₃₆ H ₃₄ N ₄ O ₄ S ₂ Sb ₂ F ₁₂ Theoretical value: C: 38.52% Measured value: 38.31% H : 3.03% 2.99% N: 4.99% 5.08%

[0010]

Since the novel azo compound of the present invention has a water-soluble active ester group at the terminal, it is useful as a polymerization initiator for obtaining a functional polymer.

Claims (3)

[Claims] 1. An azo compound represented by Chemical Formula 1 (However, R ₁ is hydrogen, any of a C ₁ -C ₄ alkyl group and a cyano group, and R ₂ and R ₃ are independently hydrogen, halogen,
Alkyl C ₁ -C _4, one of the alkoxy groups of _{C 1 ~C 4, R 4,} R 5 represents an alkyl group or a benzyl group C ₁ -C ₄ independently. X is an alkylsulfate ion, a halogen ion, a perchlorate ion, a hydrogensulfate ion, a p-toluenesulfonate ion, a hexafluoroantimonate ion, a hexafluorophosphate ion, or a tetrafluoroborate ion. Further, n is 0 or an integer of 5 or less. ) 2. A 4,4′-azobis [4-cyanopentanoic acid (4-dimethylsulfoniophenyl) ester]
Methyl sulfate. 3. A 2,2′-azobis [2-cyanopropionic acid (4-methylbenzylsulfoniophenyl) ester] hexafluoroantimonate salt.