JPS58168603A - Radical polymerization of monomer - Google Patents

Abstract

PURPOSE:To effect radical polymerization of a water-soluble or difficultly water- soluble monomer in a water phase, by radical-polymerizing the monomer in the presence of a specified aliphatic compound by using an organic solvent-soluble or -dispersible radical polymerization initiator in a binary system consisting of water and an organic solvent. CONSTITUTION:An aliphatic modified cyclodextrin compound (e.g., hexakis-2,6- O-dimethyl-alpha-cyclodextrin) is added to a binary system consisting of a water phase containing a water-soluble or difficultly water-soluble monomer e.g., (meth)acrylamide, vinyl acetate and an organic solvent phase containing an organic solvent (e.g., chloroform, ether)-soluble or -dispersible radical polymerization initiator (e.g., benzoyl peroxide, 2,2'-azobisisobutyronitrile), whereby the radical polymerization of the above monomer takes place suitably because the oleophilic modified cyclodextrin compound acts as a phase transfer agent which transfers the polymerization initiator from the organic solvent to the water phase.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for radical polymerization of water-soluble or poorly water-soluble monomers.

Conventionally, radical polymerization of water-soluble monomers has been carried out in water using a water-soluble radical polymerization initiator. However, there are very few types of water-soluble radical polymerization initiators, such as inorganic peroxides such as hydrogen peroxide, potassium persulfate-ammonium persulfate, hydrogen peroxide-ferrous salt, persulfate-acidic sodium sulfite, etc. Like redox initiators such as.

Only a limited number of these methods are available, and it is difficult to widely apply such radical polymerization.

On the other hand, there are many types of radical polymerization initiators that are soluble or dispersible in organic solvents, and each of them can be applied to the radical polymerization of a wide range of organic solvent-soluble monomers by utilizing their respective characteristics.

However, these two compounds are hardly soluble in water and are therefore not suitable for conventional radical polymerization methods of water-soluble monomers.

In addition, recently - as the development of water-soluble polymer substances progresses,
Many new water-soluble polymers have appeared, but there is no need to develop any special polymerization initiators for radical polymerization, and a method that can be used to conduct polymerization using existing polymerization initiators is needed. It is hoped that this will be established.

In view of these circumstances, the present invention uses a wide variety of organic solvent-soluble or dispersible radical polymerization initiators, and can be widely applied not only to water-soluble monomers but also to poorly water-soluble monomers. The present invention aims to provide a radical polymerization method.

Generally, when using an organic solvent-soluble or dispersible radical polymerization initiator, an organic solvent is required, but it is simply an organic solvent phase containing the initiator and an aqueous phase containing a water-soluble or poorly water-soluble monomer. Even when brought into contact with each other, radical polymerization is difficult to initiate because both phases do not mix.

However, unexpectedly, the present inventors discovered that lipophilic modification was possible in a two-phase system consisting of an aqueous phase containing a water-soluble or poorly water-soluble monomer and an organic solvent phase containing an organic solvent-soluble or dispersible radical polymerization initiator. Discovered that the IJ compound acts as a phase transport agent to transport the polymerization initiator in the organic solvent phase to the aqueous phase, and radical polymerization of water-soluble or poorly water-soluble monomers is suitably carried out in the aqueous phase. 1. Completed the present invention. I ended up doing it.

That is, according to the method of the present invention, in a two-phase system consisting of an aqueous phase containing a water-soluble or sparingly soluble monomer and an organic solvent phase containing an organic solvent-soluble or dispersible radical polymerization initiator, By adding a lipophilic modified cyclodextrin compound, radical polymerization of the monomer can be carried out in the aqueous phase. The method of the present invention does not require any special polymerization initiator and can be widely applied to various monomers that are soluble or sparingly soluble in water.

The monomers that are soluble or poorly soluble in water may be any monomers that can be dispersed or suspended in water, including so-called water-soluble monomers, even if they have low solubility in water, such as (meth). Acrylamide, 2-methyl(meth)acrylamide, N-methylol(meth)
Acrylamide, methyl (meth)acrylate, (meth)
Ethyl acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 1-chloro(meth)acrylic acid, acrylonitrile, N-vinylpyrrolidone.

Vinyl sulfonic acid, fumaric acid, itaconic acid,
Vinyl acetate, vinyl crotonate, etc. (the term (meth)acrylic means acrylic and methacrylic).

Examples of organic solvents include those that are immiscible with water, such as chloroform, ligroin, and n-hexane.

Examples include ether.

Examples of organic solvent oT14-based or dispersible radical polymerization initiators include diacyl peroxides such as penzoyl peroxide derivatives, acetyl peroxide, and lauroyl peroxide.

Dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide, methyl hydroperoxide, and [-butyl hydroperoxide.

Hydroperoxides such as cumene hydroperoxide and its derivatives, ber esters such as [-butyl perbenzoate, [-butyl peracetate, t-butyl performate], 2,2'-azobisisobutyronitrile, 2.2' -azobis-2,4-dimethylvaleronitrile, 1.1'-azobiscyclohexane-1-carbonitrile, 2,4.4-)rifthyl-2-phenylazovaleronitrile, 2.2'-azobis-4- Methoxy-2,4-dimethylvaleronitrile-1,1'-
Azobis-1-cyclobutanenitrile + 2.2'-azobis-2-methylbutyronitrile, 2.2'-azobis-2-ethylpropionitrile + 1.1''-azobis-1-cyclopentanenitrile, 2. Examples include azo compounds such as 2'-azobis-2-cyclopropylpropionitrile.

In addition, the lipophilic modified cyclodextrin compound used in the method of the present invention - at least a part of the hydrogens of the hydroxyl groups at the 2, 3 and 6 positions of its constituent glucose is replaced with an alkyl group 1, for example, up to 16 carbon atoms, preferably 1 to 1 carbon atoms. It may be α, β or r-cyclodextrin substituted with a straight chain or branched alkyl group of 6 to impart lipophilicity so as to be soluble in both water and organic solvents. Such modified cyclodextrin compounds are known or can be produced according to known methods, for example, hexakis-2,6-0-dimethyl-α
-cyclodextrin, hexakis-2,8,6-0-
) Limethyl-α-cyclodextracyheptakis-2
, 6-0-dimethyl-β-cyclodextrin, heptakis-2,8,6-0-trimethyl-β-cyclodextrin, octakis-2,6-0-dimethyl-r-cyclodextrin.

Examples include octakis-2,8,6-0-)limethyl-r-cyclodextrin.

Thus, in the method of the present invention, a two-phase system is generally prepared by dissolving or dispersing a water-soluble or sparingly soluble radical polymerization initiator and an organic solvent-soluble or dispersible radical polymerization initiator in water and an organic solvent, respectively. This is carried out by forming a lipophilic modified siphrobutycin compound and adding thereto a lipophilic modified sifurobukis compound.

Usually, 2 parts of water per 1 part (by weight, same below) of the monomer.
parts or more, preferably 5 to 100 parts, more preferably 10 to 80 parts, organic solvent 21 parts or more, preferably 2
~50 parts, more preferably 5 to 15 parts 1 polymerization initiator 0. O1 to 0.1 part, preferably 0.02 to 0°05
parts, 0.05 to 0.5 parts of the cyclodextrin compound,
Preferably, 0.1 to 0.2 parts are used at 20 to 90°C.
1. Radical polymerization is preferably carried out at 30-50°C until the desired polymer is obtained.

Next, the present invention will be explained in more detail with reference to reference examples and examples.

Reference Example 1 Preparation of heptakis-2,6-0-dimethyl-β-cyclodextrin β-cyclodextrin 91 (7,94
mmol) in dimethyl sulfoxide 150-
150-dimethylformamide was added to this and stirred well. After cooling with cold water, Ba was added to the solution in a nitrogen atmosphere.
(OH)2-8H2051f (0,162 mol) and BaO519 (0,883 mol), then dimethyl sulfur 105-1 (1°11 mol) were added to the temperature at -θ℃.
The mixture was stirred for one day and night. Furthermore, after reacting at 60°C for 6 hours, 28% aqueous ammonia was added and stirred at room temperature for 8 hours to decompose unreacted dimethyl sulfate. Formamide was removed under reduced pressure. The lifted white solid was extracted with chloroform, and the extract was dried over anhydrous sodium sulfate. The mixture was then concentrated under reduced pressure to about 40% and a large amount of n-hexane was added to precipitate a white crude β-cyclodextrin methylate. The crude product was purified by chromatography on a silica gel column, eluting with benzene-ethanol (4: l v/v), and heptakis-2,6-0-dimethyl-β
- Cyclodextrin 6.98f (82.2%) was obtained. This was roughly recrystallized from chloroform-n-hexane. Specific optical rotation [α]D+123° (C0,18
Reference Example 2 Preparation of heptakis-2,8,6-0-)rifthyl-β-cyclodextrin β-cyclodextrin 8.88F (7.88 mmol) was dissolved in dimethylformamide 400-.

The mixture was cooled to 0"C with ice water. To this was added 19.7f (0,822 mol) of IJium (hydrogenated), stirred at room temperature for 80 minutes, then cooled to 0°C, and 10% of methyl iodide was added.
4.z (1.67 mol) was added and stirred vigorously at room temperature for 5 hours. After the reaction was completed, excess methyl iodide was removed under reduced pressure and the white solid produced was removed.

The furnace liquid was concentrated under reduced pressure to about 50%
- was added. The organic layer was washed with water-0.1N sodium thiosulfate solution, then with water, and dried over anhydrous sodium sulfate. Chloroform was removed under reduced pressure, and the resulting residue was subjected to silica gel column chromatography. , benzene-ethanol (4:1 v/v) to obtain heptakis-2,8,6-0-trimethyl-β-cyclodextrin 6.1f (55%), which was further eluted with -chloroform-〇- Recrystallized from hexane and water.Specific rotation [α]p+161' (cO, i18.
Examples 1 to 4 Acrylamide 0.5 to 10 - of water according to the usual sealed tube method.
g (7.0×10 mol), also in chloroform-
Ligroin (1:4v/v) 5- to 1.1'-azobiscyclohexane-1-carbonitrile 8°64a? (8
. The amount of the cyclodextrin compound added, the yield and intrinsic viscosity of the produced polymer [') ] (I N -N
aN0a (measured at 30°C in aqueous solution) are shown in Table 1. For comparison, Table 1 also shows cases in which the cyclodextrin compound was used without twisting or with twisting.

Table 1 Examples 5 to 11 Similar to Examples 1 to 4, acrylamide was added to 10% of water and 0%.
5 f (7,0 x 1 G-3 mob) - chloroform - ligroin (1:4 v/v) 5 + d plus 8.5 x l of each organic solvent soluble polymerization initiator shown in Table 1 - 5 mol and 7.5X each lipophilic modified cyclodextrin compound
The results were shown in Table 2. For comparison, Table 2 also shows the case without the addition of the Schiflovkis l-IJ compound. show.

Note: In Table 2, each abbreviation means the one indicated.

A I BN: 2,2'-azobisinbutyronitrile ADVN: 2,2'-azobis-2,4-dimethylvaleronitrile ACN: 1,1'-azobiscyclohexane-1-carbonitrile TPVN: 2, 4.4-) Dimethyl-2-phenylazovaleronitrile HDM (p-CD): Hey” Takis-2,6-0
-dimethyl-β-cyclodextrin HTM (1-CD): to7'takis-2,8,6-0
-Trimethyl-β-cyclodextrin Patent applicant Nippon Deka Chemical Co., Ltd.

Claims (1)

[Claims] (1) In a two-phase system consisting of water and an organic solvent, a chemical compound is radically polymerized in the presence of a lipophilic modified cyclodextrin compound using an organic solvent-soluble or dispersible radical polymerization initiator. Method for radical polymerization of chemical compounds. [2) the modified sifurobukis) α, in which the IJ compound has substituted at least a portion of the hydrogens of the 2, 3 and 6-position hydroxyl groups of its constituent glucose with an alkyl group having up to 16 carbon atoms;
The polymerization method according to item (1) above, which is β or r-cyclodextrin.