JPH0233722B2 - MONOMAANORAJIKARUJUGOHOHO - Google Patents

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. Only a limited number of redox initiators are available, making it 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, since these are hardly soluble in water, they are not suitable for conventional radical polymerization methods of water-soluble monomers. In addition, with the recent progress in the development of water-soluble polymeric substances, many new water-soluble monomers have appeared, but the radical polymerization of these monomers does not require the development of any special polymerization initiators, and can be carried out using existing polymerization methods. It is desired to establish a method that can carry out polymerization using an initiator. In view of these circumstances, the present invention utilizes a wide variety of organic solvent-soluble or dispersible radical polymerization initiators to carry out radical polymerization that can be widely applied not only to water-soluble monomers but also to poorly water-soluble monomers. The purpose is to provide a 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. It was discovered that a cyclodextrin compound acts as an interphase 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, and the present invention was completed based on this discovery. It was 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. Thus, 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 sparingly soluble in water include so-called water-soluble monomers, and any monomers that can be dispersed or suspended in water, even if they have low solubility in water, such as (meth)acrylamide, 2 -Methyl (meth)acrylamide, N-methylol (meth)acrylamide, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylic acid-2 ―
Hydroxyethyl, 1-chloro(meth)acrylic acid, acrylonitrile, N-vinylpyrrolidone,
Vinyl sulfonic acid, dinitrile fumarate, 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, n-hexane,
Examples include ether. Examples of organic solvent-soluble or dispersible radical polymerization initiators include benzoyl peroxide and its derivatives, diacyl peroxides such as acetyl peroxide and lauroyl peroxide,
Dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide, hydroperoxides such as methyl hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide and derivatives thereof, t-butyl perbenzoate, t-butyl peracetate, t- Peresters such as butyl performate, 2,2'-
Azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobiscyclohexane-1-carbonitrile,
2,4,4-trimethyl-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, 2,2′-
Examples include azo compounds such as azobis-2-cyclopropylpropionitrile. Furthermore, in the lipophilic modified cyclodextrin compound used in the method of the present invention, at least a part of the hydrogens of the 2-, 3-, and 6-position hydroxyl groups of its constituent glucose are replaced with alkyl groups, for example, up to 16 carbon atoms, preferably 1 to 1 carbon atoms. It may be α-, β- or γ-cyclodextrin substituted with a straight-chain or branched alkyl group of 6 to impart lipophilicity that makes it 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-O-dimethyl-α-cyclodextrin, hexakis-2,6-O-dimethyl-α-cyclodextrin, hexakis-
2,3,6-O-trimethyl-α-cyclodextrin, heptakis-2,6-O-dimethyl-β
- Cyclodextrin, heptakis - 2, 3, 6
-O-trimethyl-β-cyclodextrin, octakis-2,6-O-dimethyl-γ-cyclodextrin, octakis-2,3,6-O-trimethyl-γ-cyclodextrin, and the like. Thus, the method of the present invention generally involves dissolving or dispersing a water-soluble or sparingly soluble monomer and an organic solvent-soluble or dispersible radical polymerization initiator in water and an organic solvent, respectively, to form a two-phase system. , by adding a lipophilic modified cyclodextrin compound thereto. Usually, the monomer 1
2 parts or more of water, preferably 5 to 100 parts, more preferably 10 to 30 parts (parts by weight, same hereinafter)
parts, 2 parts or more of organic solvent, preferably 2 to 50 parts,
More preferably, 5 to 15 parts, polymerization initiator 0.01 to
0.1 part, preferably 0.02 to 0.05 part, 0.05 to 0.5 part, preferably 0.1 to 0.05 part of the cyclodextrin compound
using 0.2 part at 20-90°C, preferably 30-50°C
Radical polymerization is carried out 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-O-dimethyl-β-cyclodextrin 9 g of β-cyclodextrin under nitrogen atmosphere
(7.94 mmol) was dissolved in 150 ml of dimethyl sulfoxide, and 150 ml of dimethyl formamide was added thereto, followed by thorough stirring. After cooling with cold water, 1 g (0.162 mol) of Ba(OH) 2.8H ₂ O _and 51 g (0.333 mol) of BaO were added to this solution under a nitrogen atmosphere, followed by 105 ml (1.11 mol) of dimethyl sulfate, and the mixture was stirred at 0°C for one day. did. Furthermore, after reacting at 60°C for 6 hours,
45 ml of 28% ammonia water was added and stirred at room temperature for 3 hours to decompose unreacted dimethyl sulfate, and then excess ammonia, dimethyl sulfoxide, and dimethyl formamide were removed under reduced pressure. The obtained white solid was extracted with chloroform, and the extract was dried over anhydrous sodium sulfate. The mixture was then concentrated to about 40 ml under reduced pressure, and a large amount of n-hexane was added to precipitate a white crude methylated β-cyclodextrin. The crude product was purified by chromatography on a silica gel column, eluting with benzene-ethanol (4:1 v/v),
6.93 g (82.2%) of heptakis-2,6-O-dimethyl-β-cyclodextrin was obtained. This was further recrystallized from chloroform-n-hexane. Specific optical rotation [α] _D +123° (c0.180, chloroform) Reference example 2 Heptakis-2,3,6-O-trimethyl-β
-Preparation of cyclodextrin 8.88 g (7.83 mmol) of β-cyclodextrin was dissolved in 400 ml of dimethylformamide and cooled to 0°C with ice water. Sodium hydride
Add 19.7 g (0.822 mol) and stir at room temperature for 30 minutes, then cool to 0°C and add 104 ml of methyl iodide.
(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 to remove the white solid produced. The liquid was concentrated under reduced pressure to about 50 ml, and 200 ml of chloroform was added. The organic layer was washed with water, a 0.1N aqueous sodium thiosulfate solution, then water, and dried over anhydrous sodium sulfate. Chloroform was removed under reduced pressure, and the resulting residue was subjected to silica gel column chromatography, and benzene-ethanol (4:1v/v)
6.1 g (55%) of heptakis-2,3,6-O-trimethyl-β-cyclodextrin
I got it. This was further recrystallized from chloroform-n-hexane and water. Specific optical rotation [α] _D
+161° (c0.118, chloroform), melting point 149-151
℃. Examples 1 to 4 Acrylamide was added to 10 ml of water according to the usual sealing method.
0.5 g (7.0 x 10 ^-3 mol) and 8.64 mg of 1,1'-azobiscyclohexane-1-carbonitrile in 5 ml of chloroform-ligroin (1:4 v/v).
(3.5×10 ^-5 mol) and heptakis-2,6-O-dimethyl-β-cyclodextrin in the amount shown in Table 1 were dissolved, and radical polymerization was carried out at 50° C. for 3 hours with shaking. The amount of the cyclodextrin compound added, the yield of the produced polymer, and the intrinsic viscosity [η] (measured at 30°C in a 1N-NaNO ₃ aqueous solution) were determined in the first step.
Shown in the table. For comparison, Table 1 also shows the case where the cyclodextrin compound was not added.

[Table] Examples 5 to 11 Similarly to Examples 1 to 4, 0.5 g of acrylamide (7.0 × 10 ^-3 mol) was added to 10 ml of water, and Table 2 was added to 5 ml of chloroform-ligroin (1:4 v/v). 3.5 x 10 ^-5 mol of each organic solvent soluble polymerization initiator and each lipophilic modified cyclodextrin compound shown in
7.5×10 ^-5 mol was dissolved and radical polymerization was performed under each reaction condition. The results are shown in Table 2. In addition,
For comparison, Table 2 also shows the case where the cyclodextrin compound was not added.

[Table] Note: In Table 2, each abbreviation means the following. AIBN: 2,2'-azobisisobutyronitrile ADVN: 2,2'-azobis-2,4-dimethylvaleronitrile ACN: 1,1'-azobiscyclohexane-1-
Carbonitrile TPVN: 2,4,4-trimethyl-2-phenylazovaleronitrile HDM (β-CD): Heptakis-2,6-O-dimethyl-β-cyclodextrin HTM (β-CD): Heptakis-2 ,3,6-O
-Trimethyl-β-cyclodextrin

Claims (1)

[Claims] 1. In a two-phase system consisting of water and an organic solvent, a monomer is radically polymerized in the presence of a lipophilic modified cyclodextrin compound using an organic solvent-soluble or dispersible radical polymerization initiator. Characteristic radical polymerization method of monomers. 2. Item 1 above, wherein the modified cyclodextrin compound is an α-, β-, or γ-cyclodextrin in which at least a portion of the hydrogens of the 2-, 3-, and 6-position hydroxyl groups of its constituent glucose are substituted with an alkyl group having up to 16 carbon atoms. polymerization method.