JP2010095623A - Method for recovering iron complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recovering a divalent or trivalent iron complex having 1,4,7-triazacyclononane compound used in a reaction as a ligand, as a trivalent iron complex reutilizable as a catalyst, in an atom transfer radical reaction. <P>SOLUTION: In an atom transfer radical reaction using, as a catalyst, a divalent or trivalent iron complex obtained by coordinating a specific cyclic amine compound to an iron compound, there is provided the method for recovering a trivalent iron complex comprising, after the reaction, subjecting a reaction mixture to the following steps (1) and (2): the step (1) in which after the reaction mixture is treated with oxygen, the iron complex and the reaction mixture are separated, or after the iron complex and the reaction mixture are separated, the iron complex is treated with oxygen; and the step (2) in which the iron complex obtained in the step (1) is treated with a halogenating agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

In the present invention, in an atom transfer radical reaction using a divalent or trivalent iron complex having a 1,4,7-triazacyclononane compound as a ligand as a catalyst, 3 The present invention relates to a method for recovering as a valent iron complex.

Unlike conventional radical polymerization, living radical polymerization, which has an activity capable of chemically converting the polymer growth terminal, can control the molecular weight, monomer residue order, dimensional structure, etc. of the polymer arbitrarily. I gathered it. Among them, in particular, the atom transfer radical polymerization reaction (ATRP) based on the combination of a metal complex and a halogen compound has shown the applicability of a wide range of monomer types. Not only synthesis, but also chemical modification of the substrate surface / interface and device construction have been extended.

In many cases, the metal catalyst used in the atom transfer radical polymerization reaction is used after mixing a compound composed of a metal and a ligand (for example, amines) into a polymerization reaction system as well as a metal complex synthesized in advance. In such a polymerization system, removal of metals and ligands from the polymer after polymerization is a major issue. In a sense, the removal of residual metals and ligands from the polymer rather than the polymerization reaction itself is a practical problem for the practical application of living radical polymerization.

Regarding removal of residual metals and ligands, 1) a method in which the solution after polymerization is completed (or diluted with a suitable solvent) is passed through an alumina or silica column, and 2) a copper component is removed by an ion exchange resin ( Non-Patent Document 1), 3) A method in which water or a poor solvent is added to a polymerization solution to separate a solid or solution polymer from a catalyst-containing solution (Patent Documents 1 to 4), and 4) a metal complexing agent. A method of use (Patent Document 5) has been studied.

In general, many of the catalysts and ligands used in atom transfer radical polymerization reactions are relatively expensive, and if they can be efficiently separated and recovered from the polymer and the catalyst components can be reused, they can be manufactured. This technology can be an industrially superior technology from the viewpoint of cost reduction as well as waste reduction. However, the low-valent metal catalyst used in the polymerization reaction is generally susceptible to air (oxygen) oxidation and needs to be stored and handled in an inert atmosphere. Therefore, in the above method, the catalyst components can be removed from the polymer, but it is difficult to recover and reuse them.
In the polymerization using an iron (divalent) -triazacyclononane complex as a low-valent iron catalyst by the present inventor, the iron catalyst can be separated from the polymer by a simple operation after polymerization, and further the separated iron catalyst Is reusable as a polymerization catalyst. However, divalent iron compounds are easily oxidized, and there are many problems from the viewpoint of industrial polymer synthesis, such as the need for recovery and reuse in an inert atmosphere (Patent Document 6).

A polymerization reaction in which the active halogen compound in the atom transfer radical polymerization reaction is replaced with a conventional radical generator (for example, a peroxide or an azo compound) is called a reverse atom transfer radical reaction. In the polymerization reaction, the catalyst used is a high-valent metal compound, and is an extremely easy-to-handle compound that exists stably in air. By adding this high-valence catalyst to the conventional radical polymerization process, living radical polymerization is possible, and reactive residues can be introduced at the ends of the polymer, thereby making it possible to synthesize block copolymers. is there. Accordingly, the reverse atom transfer type radical polymerization reaction is a useful production method capable of obtaining a polymer whose structure is controlled by an existing production process. The high valence catalyst in the iron complex is a trivalent iron complex. For example, an iron (trivalent) -triazacyclononane complex catalyst corresponding to the above-described iron (divalent) -triazacyclononane complex by the present inventor. A reverse atom transfer type radical polymerization reaction due to is reported (Patent Document 7). In this case as well, the iron catalyst can be separated from the polymer and the separated iron catalyst can be reused. However, after the polymerization is completed, the iron valence is divalent. It was necessary to carry out the utilization process in an inert atmosphere.
As described above, in the atom transfer radical polymerization reaction using either a low valence complex or a high valence complex, a reusable catalyst has a low valence, but the catalyst can be used as a high valence complex without impairing the catalytic activity. There were no reports of stable recovery and reuse.

JP 2002-356510 A JP 2002-363213 A JP2004002520 JP2008-106094 JP 2005-105265 A Japanese Patent Application No. 2005-267584 JP 2006-257293 A Matyjaszewski et al., Macromolecules, 2000, 33, 1476. Ando et al., Macromolecules, 1997, 30, 4507. Rauchfuss et al., Inorganic Chemistry, 2000, 39, 3029. McGowan et al., Inorganica Chimica Acta, 2004, 357, 689. Neuse et al., Journal of Crystallographic and Spectroscopic Research, 1986, 16, 483.

The problem to be solved by the present invention is that a divalent or trivalent iron complex having a 1,4,7-triazacyclononane compound used in the reaction as a ligand in an atom transfer radical reaction is again obtained. It is to provide a method for recovering as a trivalent iron complex that can be used as a catalyst.

The present invention relates to an iron compound represented by the general formula (1)

(In the formula (1), Fe is Y-valent (Y represents an integer of 2 or 3) and X1 represents a monovalent anionic functional group). Cyclic amine compound represented

(In the formula (2), R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring. In an atom transfer radical reaction using a Y-valent iron complex (Y represents an integer of 2 or 3) formed by coordination as a catalyst,
After completion of the reaction, a method for recovering the iron complex represented by the general formula (3) is provided by performing the following step 1) and then step 2) on the reaction mixture.
Step 1) A step of separating the iron complex and the reaction mixture after treating the reaction mixture with oxygen, or
Step of treating the iron complex with oxygen after separating the iron complex and the reaction mixture 2) Step of treating the iron complex obtained by the above step 1) with a halogenating agent

(Wherein Fe is trivalent, X ¹ represents a monovalent anionic functional group, R 1, R 2 and R 3 are carbon atoms on a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an aromatic ring. Represents a benzyl group optionally having a substituent of 1 to 40.)

According to the present invention, in an atom transfer radical reaction, a divalent or trivalent iron complex having a 1,4,7-triazacyclononane compound used in the reaction as a ligand can be converted again by a simple method. It can be recovered as a trivalent iron complex that can be used as a catalyst.

First, the iron catalyst used in the atom transfer radical reaction of the present invention will be described.
In the present invention, the iron compound represented by the general formula (1)

(In the formula (1), Fe is Y-valent (Y represents an integer of 2 or 3) and X1 represents a monovalent anionic functional group).

(In the formula (2), R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring. Characterized in that it has a cyclic amine compound represented by a Y-valent iron complex (Y represents an integer of 2 or 3) as a ligand. A triazacyclononane group having a hydrogen atom on the nitrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring is present on the iron ion. It is characterized by being coordinated and having an anionic functional group.
Examples of the anionic functional group represented by X1 include halogen ions such as fluorine ion, chlorine ion, bromine ion or iodine ion, R4COO- (wherein R4 is a carbon atom in which a hydrogen atom on a carbon atom may be substituted with a halogen atom) -4 alkyl group, or a phenyl group in which a hydrogen atom on a carbon atom may be substituted with an alkyl group having 1 to 4 carbon atoms), or R4SO3- (R4 is a hydrogen atom on a carbon atom is a halogen atom) Or an alkyl group having 1 to 4 carbon atoms which may be substituted with an atom, or a phenyl group in which a hydrogen atom on the carbon atom may be substituted with an alkyl group having 1 to 4 carbon atoms). Preferably there is. Furthermore, it is more preferable to show any one group selected from the group consisting of halogen ions, CH3COO-, C6H5COO-, CF3COO-, CH3SO3-, C6H5SO3- and CF3SO3-, for long-term stabilization of the catalytic activity. It is particularly preferable that it is a chlorine ion or a bromine ion.

The cyclic amine compound represented by the general formula (2) is a triazacyclononane having R1, R2, and R3 as substituents. Here, R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring. In terms of
1) hydrogen atom,
2) an alkyl group having 1 to 20 carbon atoms, and 3) a hydrogen atom of the aromatic ring is composed of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a polyoxyalkylene group having 1 to 40 carbon atoms. It is preferably any one group selected from the group consisting of benzyl groups which may be substituted with at least one group selected from the group. More preferably,
1) hydrogen atom,
2) from a group consisting of an alkyl group having 1 to 8 carbon atoms, and 3) a benzyl group in which the hydrogen atom of the aromatic ring may be substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. Any one group selected. Particularly preferably, it is an alkyl group having 1 to 3 carbon atoms, or a benzyl group in which an aromatic ring hydrogen atom may be substituted with an alkoxy group having 1 to 2 carbon atoms, and most preferably a methyl group, an ethyl group, or a benzyl group. Group, or 4-methoxybenzyl group. R1, R2 and R3 may be the same or different.

  Examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n -Linear alkyl groups such as octadecyl group; branched alkyl groups such as i-propyl group, i-butyl group, i-hexyl group, i-octadecyl group, sec-butyl group and tert-butyl group. Examples of the benzyl group include benzyl group, 4-methylbenzyl group, 4-ethylbenzyl group, 4-n-propylbenzyl group, 4-isopropylbenzyl group, 4-n-butylbenzyl group, and 4-isobutylbenzyl group. 4-t-butylbenzyl group, 4-methoxybenzyl group, 4-ethoxybenzyl group, 4-n-propoxybenzyl group, 4-isopropoxybenzyl group, 4-n-butoxybenzyl group, 4-isobutoxybenzyl group , 4-t-butoxybenzyl group, 4-trifluoromethyl group and the like.

More specifically, examples of the divalent iron complex of the present invention include those represented by the following general formulas (4) to (8).

(In the formula (4), Fe is divalent, X2 represents a monovalent anionic functional group, R1, R2 and R3 are a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an aromatic ring. A benzyl group optionally having a substituent having 1 to 40 carbon atoms, An- represents an anion, and n represents an integer of 1 to 3).
The anionic functional group represented by X2 is a halogen ion such as fluorine ion, chlorine ion, bromine ion or iodine ion, R4COO- (wherein R4 is a carbon atom having 1 to 1 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom) An alkyl group of 4 or a phenyl group in which a hydrogen atom on a carbon atom may be substituted with an alkyl group having 1 to 4 carbon atoms), or R4SO3- (R4 is a halogen atom in which the hydrogen atom on the carbon atom is a halogen atom) Or an alkyl group having 1 to 4 carbon atoms which may be substituted with a hydrogen atom on a carbon atom or a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms). It is preferable. Furthermore, it is more preferable to show any one group selected from the group consisting of halogen ions, CH3COO-, C6H5COO-, CF3COO-, CH3SO3-, C6H5SO3- and CF3SO3-, for long-term stabilization of the catalytic activity. It is particularly preferable that it is a chlorine ion or a bromine ion.

R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group which may have a substituent having 1 to 40 carbon atoms on the aromatic ring. In
1) hydrogen atom,
2) an alkyl group having 1 to 20 carbon atoms, and 3) a hydrogen atom of the aromatic ring is composed of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a polyoxyalkylene group having 1 to 40 carbon atoms. It is preferably any one group selected from the group consisting of benzyl groups which may be substituted with at least one group selected from the group. More preferably,
1) hydrogen atom,
2) from a group consisting of an alkyl group having 1 to 8 carbon atoms, and 3) a benzyl group in which the hydrogen atom of the aromatic ring may be substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. Any one group selected. Particularly preferably, it is an alkyl group having 1 to 3 carbon atoms, or a benzyl group in which an aromatic ring hydrogen atom may be substituted with an alkoxy group having 1 to 2 carbon atoms, and most preferably a methyl group, an ethyl group, or a benzyl group. Group, or 4-methoxybenzyl group. R1, R2 and R3 may be the same or different. n represents an integer of 1 to 3, and is preferably 1 or 2.

  Examples of the alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n -Linear alkyl groups such as octadecyl group; branched alkyl groups such as i-propyl group, i-butyl group, i-hexyl group, i-octadecyl group, sec-butyl group and tert-butyl group. Examples of the benzyl group include benzyl group, 4-methylbenzyl group, 4-ethylbenzyl group, 4-n-propylbenzyl group, 4-isopropylbenzyl group, 4-n-butylbenzyl group, and 4-isobutylbenzyl group. 4-t-butylbenzyl group, 4-methoxybenzyl group, 4-ethoxybenzyl group, 4-n-propoxybenzyl group, 4-isopropoxybenzyl group, 4-n-butoxybenzyl group, 4-isobutoxybenzyl group , 4-t-butoxybenzyl group, 4-trifluoromethyl group and the like.

Moreover, what is represented by General formula (5) is mentioned.

(In the formula (5), Fe is divalent, X3 represents a monovalent anionic functional group, R1, R2 and R3 are a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an aromatic ring. A benzyl group optionally having a substituent having 1 to 40 carbon atoms, An- represents an anion, and n represents an integer of 1 to 3).
In Formula (5), X3 is a halogen ion, a cyano group, a phenylthio group, R4COO- (R4 is a C1-C4 alkyl group in which a hydrogen atom on a carbon atom may be substituted with a halogen atom, or carbon The hydrogen atom on the atom represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.) And R4SO3- (R4 is carbon on which the hydrogen atom on the carbon atom may be substituted with a halogen atom). An alkyl group having 1 to 4 carbon atoms, or a hydrogen atom on a carbon atom represents a phenyl group optionally substituted with an alkyl group having 1 to 4 carbon atoms). Of these, halogen ions are more preferable, and chlorine ions and bromine ions are particularly preferable.
R1, R2 and R3 are the same as in the case of the general formula (2). n represents an integer of 1 to 3, and is preferably 1 or 2.
In the above general formulas (4) and (5), An- represents an anion, specifically, the following general formula (6)

(In the formula (6), Fe is divalent, X4 represents a monovalent anionic functional group, R1, R2 and R3 are a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or an aromatic ring. A benzyl group optionally having a substituent having 1 to 40 carbon atoms is shown.) Or the general formula (7)

(In formula (7), X5 represents a monovalent anionic functional group, m is 0 or 1, n is 1 when m is 0, and n is 1 or 2 when m is 1. .) Is represented.
In the above formula (6), X4 is a halogen ion, a cyano group, a phenylthio group, R4COO- (R4 is an alkyl group having 1 to 4 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom, or A hydrogen atom on a carbon atom represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms) and R4SO3- (R4 is a hydrogen atom on the carbon atom may be substituted with a halogen atom). Any one group selected from the group consisting of an alkyl group having 1 to 4 carbon atoms or a phenyl group in which a hydrogen atom on a carbon atom may be substituted with an alkyl group having 1 to 4 carbon atoms. It is preferable that a halogen ion is more preferable, and a chlorine ion and a bromine ion are particularly preferable.
R1, R2 and R3 are the same as in the case of the general formula (2). n represents an integer of 1 to 3, and is preferably 1 or 2.
In the above formula (7), X5 is preferably a fluorine ion, a chlorine ion, a bromine ion or an iodine ion, and particularly preferably a chlorine ion or a bromine ion.

Of such iron complexes, the following are most preferred.
(I) In general formula (4) and general formula (6), R1, R2 and R3 are methyl groups, X2 and X4 are chlorine ions, and n is 1.
(Ii) An iron complex in which R1, R2, and R3 are methyl groups, X2 and X4 are bromine ions, and n is 1 in general formula (4) and general formula (6).
(Iii) The iron complex in which R1, R2, and R3 are ethyl groups, X2 and X4 are chlorine ions, and n is 1 in general formula (4) and general formula (6).
(Iv) In the general formula (4), R1, R2, and R3 are ethyl groups, X2 is a bromine ion, n is 1, in the general formula (7), X5 is a bromine ion, and m is 1. An iron complex in which n is 1.
(V) In the general formula (4), R1, R2, and R3 are benzyl groups, X2 is a bromine ion, n is 1, and in the general formula (7), X3 is a bromine ion, and m is 1. An iron complex in which n is 1.
(Vi) In the general formula (4), R1, R2 and R3 are 4-methoxybenzyl groups, X2 is a chlorine ion, n is 1, and in the general formula (7), X5 is a chlorine ion. , M is 0 and n is 1.
(Vii) In the general formula (4), R1, R2 and R3 are 4-methoxybenzyl groups, X2 is a chlorine ion, n is 2, and in the general formula (7), X5 is a chlorine ion. , M is 1, and n is 2.
(Viii) In the general formula (4), R1, R2 and R3 are n-butyl groups, X2 is a chlorine ion, n is 1, and in the general formula (7), X5 is a chlorine ion, An iron complex in which m is 1 and n is 1.

According to the present invention, the triazacyclononane compound having various substituents on the nitrogen atom and FeCl2 or FeBr2 are used in appropriate combination to be represented by the above general formulas (4) to (7). Cation type dinuclear iron complexes having different anion moieties (A) can be obtained in good yield. By such a synthesis method, an iron complex having high solubility in a polymerizable monomer or an organic solvent is provided by increasing the number of carbon atoms of R1, R2, and R3 in the general formulas (4) to (7). be able to.
Furthermore, the thing of the structure represented by General formula (8) is mentioned.

(In the formula (8), Fe is divalent, and R1, R2 and R3 may have a hydrocarbon group having 1 to 20 carbon atoms or a substituent having 1 to 40 carbon atoms on the aromatic ring. A good benzyl group, and X6 represents a monovalent anionic functional group.)
R1, R2 and R3 are the same as in the case of the general formula (2), but a substituent which is a secondary alkyl group such as an isopropyl group, cycloheptyl, or phenylethyl group is particularly preferable.
X6 represents a halogen ion, a cyano group, a phenylthio group, R4COO- (wherein R4 represents an alkyl group having 1 to 4 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom, or a hydrogen atom on the carbon atom). Represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms) and R4SO3- (R4 is an alkyl group having 1 to 4 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom); A hydrogen atom on a carbon atom or a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.), Preferably a group selected from the group consisting of halogen ions Are more preferable, and chlorine ion and bromine ion are particularly preferable.
Furthermore, the thing of the structure represented by General formula (9) is mentioned.

（式（９）中、Ｆｅは２価であり、Ｒ１、Ｒ２及びＲ３は、炭素数１〜２０の炭化水素基又は芳香環上に炭素数１〜４０の置換基を有していてもよいベンジル基を示し、Ｘ７は１価のアニオン性官能基を示す。）

(In Formula (9), Fe is bivalent and R1, R2, and R3 may have a C1-C20 hydrocarbon group or a C1-C40 substituent on an aromatic ring. Represents a benzyl group, and X7 represents a monovalent anionic functional group.)

  In the divalent iron complex used in the present invention, the structure of the divalent iron complex among the above general formulas (4) to (9) varies depending on the types and combinations of R1, R2 and R3. There is no particular limitation on the structure of the divalent iron complex used in the above.

By increasing the number of carbon atoms of R1, R2 and R3 in the general formulas (4) to (9), an iron complex having high solubility in a polymerization monomer or an organic solvent can be provided. More specifically, an N—R1, N′—R2, N ″ —R3-1,4,7-triazacyclononane solution is added to a suspension of Fe (X1) 2 and a solvent at room temperature and stirred. It can be prepared by adding ether or the like and allowing to stand.

Specifically, examples of the general formula (4) include complexes represented by the following general formula (4 ′) and general formula (4 ″).

(In the formula (4 ′), Fe is all divalent, X8 represents any of fluorine ion, chlorine ion, bromine ion or iodine ion, and X9 represents a halogen ion, a cyano group, a phenylthio group, R 4 COO— ( In R4, a hydrogen atom on the carbon atom may be substituted with a halogen atom, or an alkyl group having 1 to 4 carbon atoms, or a hydrogen atom on the carbon atom may be substituted with an alkyl group having 1 to 4 carbon atoms. Represents a phenyl group.) And R4SO3- (wherein R4 represents an alkyl group having 1 to 4 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom, or a hydrogen atom on the carbon atom having 1 to 4 carbon atoms). And represents any one group selected from the group consisting of R1, R2 and R3 are the same as those in the formula (2). Of these, X8 and X9 are preferably chlorine ions or bromine ions.

(In the formula (4 ″), Fe is all divalent, X8 represents one of fluorine ion, chlorine ion, bromine ion or iodine ion, X10 represents a halogen ion, and R1, R2 and R3 are Same as in formula (2): m is 0 or 1, n is 1 when m is 0, and n is 1 or 2 when m is 1.) Among these, X8 and X10 is preferably a chlorine ion or a bromine ion.

On the other hand, the trivalent iron complex of the present invention includes those represented by the following formula (10).

(In the formula (10), Fe is trivalent, X ¹¹ represents a monovalent anionic functional group, R 1, R 2 and R 3 are a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or an aromatic ring. Represents a benzyl group optionally having a substituent having 1 to 40 carbon atoms.)
X ¹¹ is more preferably a halogen ion among the anionic functional groups, particularly preferably a chlorine ion or a bromine ion, and R 1, R 2 and R 3 are each a hydrocarbon group having a lower alkyl group such as a methyl group or an ethyl group. Preferably, in the case of a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring, the benzyl substituted with a lower alkoxy group such as a benzyl group having no substituent or a 4-methoxybenzyl group The group is particularly preferred.

  When a polymerization reaction of a radical polymerizable monomer is performed using the catalysts represented by the general formulas (4) to (9), examples of the organic halogen compound used in the polymerization reaction include an α-halogenocarbonyl compound, α It is preferably at least one organic halogen compound selected from the group consisting of halogenocarboxylic acid esters, α-halogenoalkylarenes, sulfonyl halides, and polyhalogenated alkanes. More specifically, 2-chloroacetophenone, 2-bromoacetophenone, 2,2-dichloroacetophenone, 2,2-dibromoacetophenone, 1-chloro-2-propanone, 1-bromo-2-propanone, 1,1-dichloro Carbonyl compounds such as 2-propanone, 1,1-dibromo-2-propanone, or methyl 2-chloropropionate, ethyl 2-bromopropionate, methyl dichloroacetate, ethyl dibromoacetate, 2-bromo-isobutyric acid Ethyl, ethyl 1-chloro-1-phenylacetate, ethyl 1-bromo-1-phenylacetate, anthracenylmethyl 2-bromo-isobutyrate, dimethyl 2-chloro-2,4,4-trimethylglutarate, 1, Esters such as 2-bis (2-bromoisobutyryloxy) ethane, benzenesulfone Sulfonyl halides such as chloride, p-toluenesulfonic acid chloride, p-toluenesulfonic acid bromide, (1-chloroethyl) benzene, (1-bromoethyl) benzene, (1-iodoethyl) benzene, α, α-dichlorotoluene, Examples include α-halogenoalkylarenes such as α, α-dibromotoluene, and compounds of polyhalogens such as carbon tetrachloride and carbon tetrabromide.

  By using an active halogen compound having three or more active sites as the organic halogen compound, a star polymer can be easily synthesized. Examples include 1,3,5-tris (chloromethyl) benzene, 1,3,5-tris (bromomethyl) benzene, 1,3,5-tris (1-chloroethyl) benzene, 1,3,5-tris. (1-bromoethyl) benzene, 1,2,4,5-tetrakis (chloromethyl) benzene, 1,2,4,5-tetrakis (bromomethyl) benzene, 1,2,3,4,5,6-hexakis ( And α-halogenoalkylarenes compounds such as chloromethyl) benzene and 1,2,3,4,5,6-hexakis (bromomethyl) benzene.

Moreover, the polymer which has the said halogen compound residue in the terminal or side chain of a polymer can also be used as a polymerization initiator. For example, polyhaloacrylates, polyacrylates, polyacrylamides, polystyrenes, polyvinyl pyridines, polyethylene glycols, polyethers The above halogen compound residues at one or both ends of the polymer, for example, α-halogenocarbonyl, A polymer to which an α-halogenocarboxylic acid ester residue is bonded can be suitably used. In addition, for example, a polymer having a hydroxyl group in a side chain and a halogen compound residue, for example, an α-halogenocarboxylic acid residue, can be used, such as a polymer such as epoxy resins, polyvinyl alcohols, and polysaccharides. . When such a polymer is used as a halogen compound, a block polymer or a comb polymer can be easily obtained.

  When the iron complex represented by the general formulas (4) to (9) and the organic halogen compound are used in combination, the molar ratio represented by the complex / organic halogen compound is in the range of 0.1 to 1. However, in view of high iron catalyst activity, it is preferable that the organic halogen compound is in excess of the complex.

  In the polymerization reaction using the iron complex represented by the general formula (10) in the present invention, as a radical generator, if it is usually used in radical polymerization of vinyl monomers, Of course, any one of them can be used, and a typical example of them can be used as a perme such as t-butyl peroxy (2-ethylhexanoate) and t-butyl peroxybenzoate. Organic compounds such as oxyesters, dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide, and peroxyketals such as 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane Peroxides: azobisisobutyronitrile, azobiscyclohexanecarbonitrile, 2,2'-azobis (2,4-dimethyl Reronitoriru) azo compounds such as and the like.

  Moreover, a water-soluble peroxide and a water-soluble azo compound can also be used as a radical generator. For example, hydroxy-t-butyl peroxide, ammonium peroxide sulfate, potassium peroxide sulfate, peroxides such as hydrogen peroxide, and azo polymerization initiators such as VA-046B, VA-057, VA-060, VA -067, VA-086, VA-044, V-50, VA-061, VA-080, and the like. In particular, by using an azo-based water-soluble initiator, a useful functional group derived from an initiator residue can be introduced at one end of the polymer.

  The atom transfer radical reaction by the iron complex of the present invention can be applied to radical polymerizable monomers in general. Examples of the polymerizable monomer include (meth) acrylates, (meth) acrylamides, styrenes, vinyl pyridines and the like. More specifically, methacrylate monomers such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-dimethylaminoethyl methacrylate, or methyl acrylate, Acrylate monomers such as ethyl acrylate, butyl acrylate, t-butyl acrylate, hexyl acrylate, cyclohexyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, 2-dimethylaminoethyl acrylate, or N, N-dimethylacrylamide, N, N -Acrylic acid such as diethyl acrylamide and N-isopropyl acrylamide Styrene monomers such as styrene, 2-chloromethyl styrene, 3-chloromethyl styrene, 4-chloromethyl styrene, p-methoxy styrene, p-vinyl benzoate, p-vinyl phenyl sulfonate, Alternatively, vinyl pyridine monomers such as p-vinyl pyridine and o-vinyl pyridine can be used.

These monomers can be used alone or in combination of two or more kinds. Two or more types of monomers can be added and used at regular intervals of the polymerization reaction. By adding the next monomer after the first monomer is consumed, the resulting polymer can be made into a diblock, triblock, or higher block copolymer structure.

  In the synthesis with a block copolymer, a block copolymer composed of the two polymer skeletons can be obtained by selecting a polymerizable monomer from styrene and (meth) acrylate. Further, by using a hydrophilic monomer and a hydrophobic monomer, an amphiphilic block copolymer comprising a hydrophilic polymer skeleton and a hydrophobic polymer skeleton can be obtained.

  Moreover, as a method for obtaining a block copolymer, a polymerizable monomer can be polymerized by using a polymer having a halogen residue at the terminal as a macroinitiator.

  When obtaining a block copolymer, when a basic monomer is used as a polymerizable monomer, a block copolymer composed of a basic polymer skeleton and another polymer skeleton can be obtained.

  When a polymerizable monomer and an organic halogen compound or radical generator are mixed and polymerized, the molar ratio represented by the polymerizable monomer / halogen compound or radical generator should be 10 to 10,000, and the degree of polymerization can be improved. In order to control, the molar ratio is more preferably 50 to 1000.

  When performing a polymerization reaction using the polymerization initiator system in the present invention, the reaction temperature can be set to room temperature or higher, but it is preferable to perform the reaction in a temperature range of 30 to 120 degrees.

  The reaction time is sufficient in the range of 1 to 48 hours, but the reaction time can be set shorter or longer depending on the type of halogen compound or radical generator, the type of olefin monomer, and the reaction temperature. Furthermore, it is desirable to set the reaction time according to the molecular weight control of the obtained copolymer.

  In the copolymerization reaction in the present invention, different polymerization methods such as bulk polymerization without a solvent, solution polymerization in the presence of a solvent, or polymerization in an alcohol solvent or an aqueous medium can be applied.

  Solvents that can be used in the polymerization reaction of the present invention include dichloromethane, 1,2-dichloroethane, tetrahydrofuran, acetonitrile, butyl acetate, benzene, toluene, chlorobenzene, dichlorobenzene, anisole, cyanobenzene, dimethylformamide, N, N- Examples include dimethylacetamide, methyl ethyl ketone, methanol, ethanol, propanol, butanol, pentanol, hexanol and the like, and acetonitrile, butyl acetate, toluene, and anisole are preferable.

  In the polymerization in an aqueous medium, organic solvents that can be mixed with water at an arbitrary ratio are preferable. Specifically, methanol, ethanol, acetone, acetonitrile, dimethylacetamide, dimethylformamide, tetrahydrofuran and the like can be used.

  Furthermore, the water-soluble monomer can be polymerized in complete water. Alternatively, the polymerization can be carried out by dispersing a hydrophobic monomer in water.

  Next, a method for recovering the iron complex after completion of the atom transfer radical reaction will be described.

In the recovery method of the present invention, the iron compound represented by the general formula (1)

(In the formula (1), Fe is Y-valent (Y represents an integer of 2 or 3) and X1 represents a monovalent anionic functional group). Cyclic amine compound represented

(In the formula (2), R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring. In an atom transfer radical reaction using a Y-valent iron complex (Y represents an integer of 2 or 3) formed by coordination as a catalyst,
After completion of the reaction, the reaction mixture is characterized by recovering the iron complex represented by the general formula (3) by performing the following step 1) and then step 2).
Step 1) A step of separating the iron complex and the reaction mixture after treating the reaction mixture with oxygen, or
Step of treating the iron complex with oxygen after separating the iron complex and the reaction mixture 2) Step of treating the iron complex obtained by the above step 1) with a halogenating agent

(Wherein Fe is trivalent, X ¹ represents a monovalent anionic functional group, R 1, R 2 and R 3 are carbon atoms on a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an aromatic ring. Represents a benzyl group optionally having a substituent of 1 to 40.)

In the recovery method of the present invention, first, the reaction mixture is treated with oxygen. As oxygen, an oxygen gas can be used, or a gas containing oxygen, for example, air can be used. The treatment with oxygen can be performed by bringing oxygen into contact with the reaction mixture after completion of the reaction. As a method of contacting, oxygen can be introduced into the reaction vessel containing the reaction mixture and the reaction mixture can be mixed after the oxygen atmosphere is brought into an oxygen atmosphere. However, a tube for introducing oxygen is introduced into the reaction mixture. Alternatively, oxygen can be injected into the reaction mixture through a tube.
By performing the treatment with oxygen, for example, when the following complex 1 is used, an oxidized crosslinked complex represented by the following complex 3 can be obtained.

The preferable temperature in the oxygen treatment in this step is 20 to 40 ° C., and the treatment time is usually 0.5 to 1 hour.
Since the oxidized crosslinked complex usually precipitates from the reaction mixture, it can be easily isolated by a generally known method such as filtration or centrifugation.
Further, after the reaction mixture and the iron complex are separated, oxygen treatment may be performed. For example, after the polymerization is completed, the solution containing the polymer and the divalent iron complex is separated by a reprecipitation operation. The solution may be placed in an oxygen atmosphere and oxidized.
Next, the oxidized cross-linked complex obtained by the oxygen treatment is treated with a halogenating agent to obtain an iron complex represented by the general formula (3).
As the halogenating agent used, trialkylsilyl halides such as trimethylchlorosilane and trimethylbromosilane, and hydrogen halides such as hydrogen chloride and hydrogen bromide can be used. As the hydrogen halide, hydrogen halide such as hydrogen chloride or hydrogen bromide is preferable. The hydrogen halide can be preferably used either water-containing or anhydrous, but it is more preferable because the trivalent iron complex represented by the general formula (3) obtained in an anhydrous manner is high in yield.
When anhydrous hydrogen halide is used, it is desirable to use it in the form of a solution by dissolving it in alcohol, ether, haloalkane or the like. When hydrogen chloride is used, a hydrogen chloride methanol solution or a hydrogen chloride diethyl ether solution may be used. When hydrogen bromide is used as the hydrogen halide, a hydrogen bromide chloroform solution may be used.
The preferable temperature in the hydrogen halide treatment in this step is 20 to 40 ° C., and the treatment time is usually 0.5 to 1 hour.
After the treatment, the trivalent iron complex represented by the general formula (3) usually precipitates from the reaction mixture and can be easily isolated by a generally known method such as filtration or centrifugation. At that time, an organic solvent which is a poor solvent for the trivalent iron complex represented by the general formula (3) may be added to improve the recovery rate.
The trivalent iron complex obtained by the recovery method of the present invention has a catalytic ability equivalent to that of an unused trivalent iron catalyst for the post-adjustment reaction as a polymerization catalyst in an atom transfer radical reaction.

The polymer and block copolymer obtained by the production method of the present invention are used in various applications such as ink, pigment dispersion, color filter, film, paint, molding material, adhesive, electrical / electronic product member, medical member. It can be used widely.

Hereinafter, the present invention will be described in more detail with examples and comparative examples.

Measurements in the examples were performed by the following methods.
(GPC measurement method)
High-performance liquid chromatography (Waters GPC610 differential refractometer system), UV and RI detector, columns used: Showdex KF802 × 1 + KF803 × 1 + KF804 × 2, solvent THF, flow rate: 1.0 mL / min, temperature Tuning: Measured at 40 ° C.
(NMR measurement)
The measurement of ¹ H-NMR was performed with Lambda 300 manufactured by JEOL.

(Synthesis Example 1) Synthesis of Iron Complex 1 (Reference: Inorganic Chemistry 2000, 39, 3029)
In a reaction solution in which FeCl ₂ (317 mg, 2.50 mmol) and 20 mL of acetonitrile were suspended in a 100 mL Schlenk tube and suspended, 1,4,7-trimethyl-1,4,7-triazacyclononane (441.1 mg, 441.1 mg, 2.58 mmol) was added, and the mixture was stirred for 2 hours, and then insoluble matters were removed by filtration. After concentration under reduced pressure until the volume of the reaction solution reached about 5 mL, 50 mL of ether was added to precipitate a white solid. This solid was recrystallized from acetonitrile / ether to obtain 664 mg of iron complex 1 (yield 89%).

(Synthesis Example 2) Synthesis of Iron Complex 2 To a 500 mL four-necked flask equipped with a stirrer, a dropping funnel and a reflux tube, anhydrous FeCl ₃ (2.43 g, 15 mmol) and 200 mL of anhydrous diethyl ether were added under an argon atmosphere. After complete dissolution, 50 mL of 1,4,7-trimethyl-1,4,7-triazacyclononane (3.08 g, 18 mmol) in anhydrous diethyl ether was slowly added dropwise at room temperature and stirred for 1 hour. Thereafter, the crude product containing the iron complex 1 was separated by filtration. This solid was dissolved in 500 mL of acetonitrile with heating and insoluble matters were removed by filtration, and then the filtrate was concentrated to obtain orange iron complex 2. (Yield: 4.50 g, 90% yield). The structure of the complex was confirmed by single crystal X-ray structural analysis.

Example 1
<Step 1: Formation of oxygen-bridged iron complex 3 by oxygen treatment of divalent iron complex>
The divalent iron complex 1 (260 mg, 0.261 mmol) synthesized in Synthesis Example 1 was charged into a 50 mL Schlenk tube under an argon atmosphere and dissolved in 20 mL of dehydrated acetonitrile. At this time, the state of the solution was a pale yellow uniform solution. This solution was degassed under reduced pressure, and immediately after being brought to an atmosphere of oxygen at 1 atm using a balloon at room temperature, the solution immediately turned dark green, and when stirred for about 5 minutes, an orange crystalline powder was precipitated. The supernatant color at this time was also orange. After stirring for 15 minutes, the solution was allowed to stand, the supernatant was taken out with a syringe, the remaining powder was washed twice with 20 mL of diethyl ether, and dried under reduced pressure to obtain a brown powdered iron complex 3 in a yield of 86% ( 220 mg, 0.359 mmol). The IR spectrum of the iron complex 3 is shown in FIG.
(Reference: Inorganic Chemistry 2000, 39, 3029)

<Step 2: Synthesis of iron complex 2 by hydrogen chloride treatment of iron complex 3>
The iron complex 3 (30 mg, 0.049 mmol) and 8 mL of dehydrated methanol were added to a 20 mL Schlenk tube and stirred for 10 minutes to obtain a uniform solution. At this time, the color of the solution was orange. When 0.5 mL (0.5 mmol) of a 1 mol / L hydrogen chloride diethyl ether solution was added to this solution at room temperature, the color of the solution immediately changed to yellow, and a small amount of yellow powder was precipitated. After stirring for 10 minutes, the reaction solvent was distilled off under reduced pressure. The obtained yellow powder was subjected to IR measurement to confirm that iron complex 2 was quantitatively formed, and then this yellow powder was washed twice with 5 mL of diethyl ether, dried under reduced pressure, and 30 mg of iron complex. 2 was obtained (yield 92%, 0.09 mmol). The IR spectrum of the iron complex 2 is shown in FIG.

(Example 2)
Instead of 1 mol / L hydrogen chloride diethyl ether solution, chlorotrimethylsilane (Me ₃
The same procedure as in Example 1 was performed except that (SiCl) (54.3 mg, 0.5 mmol) was used. Iron complex 2 was produced quantitatively, yielding 29 mg of iron complex 2 (yield 89%, 0.087 mmol). A comparison of the IR spectra of the obtained iron complex 2 is shown in FIG.

(Test example) Confirmation of change in valence of iron complex in polymerization of polystyrene Iron tube 2 (16 mg, 0.048 mmol), AIBN (4 mg, 0.024 mmol) synthesized from Stirrer, Synthetic Example 2 in a test tube with a thread Styrene monomer (1 g, 9.6 mmol) was added, and argon gas was blown in for 1 hour, and then the vessel was sealed and stirred in an oil bath at 100 ° C. for 30 hours. The conversion rate at this time was 95%. This polymer was dissolved in THF (2 mL) degassed in advance under an argon atmosphere and dropped into methanol (20 mL) degassed in advance for reprecipitation purification. The precipitated polymer and the solution portion containing the catalyst were each dried under reduced pressure to recover 980 mg of nearly colorless polystyrene (Mn = 23000, Mw / Mn = 1.3) and 18 mg of a yellow solid containing an iron complex. When 1H-NMR of this yellow solid was measured, it was a cationic divalent iron complex similar to iron complex 1. A comparison of ¹ H-NMR spectra is shown in FIG.
In an argon atmosphere, add a stir bar, 18 mg of the catalyst-containing solid recovered above, a previously degassed styrene monomer (1.04 g, 10 mmol), and 1-chloroethylbenzene (5.6 mg, 0.04 mmol) to a test tube with a thread. It was. The vessel was sealed and stirred in an oil bath at 120 ° C. for 20 hours. The conversion was 90%, and the produced polystyrene had Mn = 25000 and Mw / Mn = 1.4.
According to this test example, it was confirmed that the iron complex was divalent after the reaction.

In the polymerization reaction using a trivalent iron complex as a catalyst, it is confirmed that the divalent iron complex exists in the reaction system after the polymerization is completed, and the divalent iron complex can be reused as the next polymerization catalyst. did.

(Example 3) Recovery of trivalent iron complex 2 in polymerization reaction (polymerization reaction of styrene monomer)
In a 200 mL reaction vessel equipped with a stirrer and a reflux tube, iron complex 2 (1.0 g, 3.0 mmol) synthesized from Synthesis Example 2, styrene monomer (62.4 g, 0.6 mol), azobiscyclohexanecarbonitrile. (367 mg, 1.5 mmol) was charged, and argon gas was blown for 1 hour, followed by stirring at 120 ° C. for 16 hours in an argon atmosphere. The conversion rate at this time was 95% or more, and when the reaction mixture was subjected to GPC analysis, Mn = 22600 and Mw / Mn = 1.28.

(Step 1: Separation of oxygen-bridged iron complex 3 by air treatment)
After cooling the reaction mixture to 100 ° C., toluene (240 g) into which argon gas had been previously blown was added to dissolve the polymer. Subsequently, this toluene solution was cooled to room temperature, and air was blown in for 2 hours with stirring. At this time, the toluene solution changed from a yellow uniform solution to a brown heterogeneous solution. The solution was filtered and separated into a brown solid and a yellow solution. The obtained brown solid was washed with a small amount of toluene and then dried under reduced pressure to obtain 877 mg of a brown powder. When the IR spectrum of this brown powder was measured, it almost coincided with the oxygen-bridged iron complex 3 in Example 1. The recovery rate of the iron complex as an oxygen bridged complex was 95%. The IR spectrum is shown in FIG.

(Step 2: Regeneration of iron complex 2 by treatment of iron complex 3 with hydrogen chloride)
In 50 mL of Schlenk, the iron complex 2 (92 mg, 0.15 mmol) and 24 mL of dehydrated methanol were added and stirred for 30 minutes. At this time, the color of the solution was orange. To this solution, 1.2 mL (1.5 mmol) of a 1.25 mol / L hydrogen chloride methanol solution was added at room temperature and stirred overnight, resulting in a yellow heterogeneous solution. This solution was filtered, and the resulting solid was washed twice with 20 mL of diethyl ether and dried under reduced pressure to obtain 76 mg of a yellow powder. When the IR spectrum was measured, it was found that it almost coincided with the trivalent iron complex 4 and that the iron complex 2 could be regenerated. (Yield 76%, 0.23 mmol). The IR spectrum of the iron complex 2 before and after regeneration is shown in FIG.

(Polymerization reaction of styrene monomer using regenerated trivalent iron complex)
In a 50 mL reaction vessel, the regenerated iron complex 2 obtained above (83.3 mg, 0.25 mmol), styrene monomer (5.12 g, 50 mmol), azobiscyclohexanecarbonitrile (30.5 mg, 0.125 mmol) were added. After charging and blowing in argon gas for 1 hour, the mixture was stirred at 120 ° C. for 16 hours in an argon atmosphere. The conversion rate at this time was 95% or more. When the reaction mixture was subjected to GPC analysis, Mn = 23600 and Mw / Mn = 1.29.

FIG. 5 shows a GPC chart of the polymerization using the synthesized iron complex 2 (upper) and the polymerization using the regenerated iron complex 2 (lower). In this way, the regenerated iron complex can be used again for polymerization, and a polymerization reaction can be suitably performed even if it is reused.

(Example 4) Recovery of trivalent iron complex 2 in polymerization reaction of methyl methacrylate Under argon atmosphere, stir bar, iron complex 2 (33.3 mg, 0.1 mmol), AIBN (8. 2 mg, 0.05 mmol) was added, and methyl methacrylate (2.0 g, 20 mmol) and acetonitrile 2 mL were added. After blowing argon gas for 1 hour, the container was sealed and stirred at 80 ° C. for 14 hours. The conversion rate at this time was 95% or more, and when the reaction mixture was subjected to GPC analysis, Mn = 29300 and Mw / Mn = 1.42. The reaction mixture was diluted with 15 mL of toluene, and air was blown for 1 hour with stirring. At this time, the toluene solution changed to a brown heterogeneous solution. The solution was filtered and separated into a brown solid and a yellow solution. The obtained brown solid was washed with a small amount of toluene and dried under reduced pressure to obtain 32 mg of a brown powder.
Subsequently, this brown solid whole quantity and dehydrated methanol 10mL were added in 50 mL Schlenk, and it stirred for 30 minutes. At this time, the color of the solution was orange. To this solution, 0.4 mL (0.5 mmol) of a 1.25 mol / L hydrogen chloride methanol solution was added at room temperature and stirred overnight, resulting in a yellow heterogeneous solution. This solution was filtered, and the resulting solid was washed twice with 20 mL of diethyl ether and dried under reduced pressure to obtain 28 mg of a yellow powder. When the IR spectrum was measured, it almost coincided with the trivalent iron complex 2.

(Synthesis Example 3) Synthesis of Iron Complex 4 1,4,7-Tris (4-methoxybenzyl) was suspended in a reaction solution in which 26 mg (0.2 mmol) of anhydrous FeCl ₂ and 10 mL of acetonitrile were added and suspended in a 20 mL Schlenk tube. -1,4,7-Triazacyclononane 100 mg (0.2 mmol) was added and stirred for 14 hours. After concentration under reduced pressure until the volume of the reaction solution reached about 5 mL, 15 mL of diethyl ether was added to precipitate a white solid. This solid was recrystallized from acetonitrile / diethyl ether to obtain iron complex 4 (mixture of complexes of Chemical Formulas 32 and 33) as a mixture of two types (86 mg). The structure of the complex was confirmed by single crystal X-ray structural analysis. This is shown in FIGS.

(Synthesis Example 4) Synthesis of iron complex 5 To a 200 mL reaction vessel equipped with a stirrer and a dropping funnel, 422 mg (2.6 mmol) of anhydrous FeCl ₃ and 80 mL of anhydrous diethyl ether were added and dissolved completely in an argon atmosphere. 15 mL of 1,4,7-tris (4-methoxybenzyl) -1,4,7-triazacyclononane 978 mg (2.0 mmol) in anhydrous diethyl ether was slowly added dropwise at room temperature and stirred for 1 hour, The crude product containing complex 5 was isolated by filtration. This solid was dissolved in 130 mL of methylene chloride and insoluble matters were removed by filtration, and then the filtrate was concentrated to obtain Yamabuki-colored iron complex 5 (Chemical Formula 35) (1.22 g, yield 94%). The structure of the complex was confirmed by single crystal X-ray structural analysis. This is shown in FIG.

(Example 5) Conversion from divalent iron complex to trivalent iron complex (Step 1: Synthesis of oxygen-bridged iron complex 6 by oxygen treatment of divalent iron complex)
The iron complex 4 (50 mg) synthesized in Synthesis Example 3 was dissolved in acetonitrile (5 mL), placed in an oxygen atmosphere, and stirred for 15 minutes. In the meantime, the color of the solution changed to reddish brown, and when stirring was continued for about 5 minutes, a precipitate started to precipitate. The supernatant solution was extracted, and the solid was washed twice with diethyl ether and then dried to obtain iron complex 6 (25 mg). The structure of the obtained complex was clarified by X-ray crystal structure analysis. The structure is shown in FIG.

(Step 2: Synthesis of iron complex 5 by treatment of iron complex 6 with hydrochloric acid)
In a 20 mL Schlenk tube, iron complex 6 (25 mg, 0.02 mmol), methanol (5 mL), and benzene (6 mL) were added and dissolved. When 0.1 mL (0.1 mmol) of a 1 mol / L hydrogen chloride diethyl ether solution was added to the obtained yellow solution at room temperature, the color immediately changed. After stirring for 10 minutes, the solvent was distilled off to obtain iron complex 5 quantitatively as a yellow solid (26 mg). The structure of the obtained complex was clarified by X-ray crystal structure analysis after recrystallization with methylene chloride, toluene, and ether. FIG. 10 shows the IR spectra of the oxygen-bridged iron complex 6 and the iron complex 5 before and after the regeneration.

Example 6 Recovery of trivalent iron complex 5 in a polymerization reaction using divalent iron complex 4 (polystyrene synthesis)
Under a nitrogen atmosphere, a Schlenk tube was charged with a stirrer, the iron complex 4 synthesized in Synthesis Example 3 (24 mg, 0.02 mmol), 1-chloroethylbenzene (5.6 mg, 0.04 mmol), and styrene (1.04 g). , 10 mmol). The vessel was sealed and stirred in an oil bath at 120 ° C. for 26 hours. The conversion was 95% or more, and the produced polystyrene had Mn = 23000 and Mw / Mn = 1.27.

(Step 1: Separation of oxygen-bridged iron complex 6 by air treatment)
After cooling the reaction mixture to 100 ° C., toluene (4 g) into which argon gas had been previously blown was added to dissolve the polymer. Subsequently, this toluene solution was cooled to room temperature, and air was blown in for 1 hour with stirring. At this time, the toluene solution changed from a yellow uniform solution to a brown heterogeneous solution. The solution was filtered and separated into a brown solid and a yellow solution. The obtained brown solid was washed with a small amount of toluene and then dried under reduced pressure to obtain 14 mg of a brown powder. On the other hand, a yellow solution containing polystyrene was dropped into 24 g of methanol with stirring, and the precipitated polystyrene was separated by filtration, and then the filtrate was concentrated to obtain a brown solid. This was washed with diethyl ether and then dried under reduced pressure to obtain 9 mg of brown powder. When the IR spectrum of these brown powders was measured, it almost coincided with the oxygen-bridged iron complex 6 in Example 3. The recovery rate of the iron complex as an oxygen bridged complex was 95%.

(Step 2: Regeneration of iron complex 5 by treatment of iron complex 6 with hydrochloric acid)
A yellow solid was obtained in the same manner as in Example 5 except that this brown solid was used instead of the iron complex 6 in Example 5 (25 mg). When the IR spectrum of the obtained solid was measured, it almost coincided with the iron complex 5 in Example 5.
(Polymerization reaction of styrene monomer using regenerated trivalent iron complex)
Under argon atmosphere, a Schlenk tube was mixed with a stirrer, the regenerated iron complex 5 (25 mg, 0.02 mmol), azobiscyclohexanecarbonitrile (2.4 mg, 0.01 mmol), pre-degassed styrene monomer (832 mg, 8 mmol). And stirred at 120 ° C. for 16 hours under an argon atmosphere. The conversion rate at this time was 95% or more. When the reaction mixture was subjected to GPC analysis, Mn = 23000 and Mw / Mn = 1.21.

(Example 7) Recovery of trivalent iron complex 5 in polymerization reaction (polymerization reaction of styrene monomer)
In a 200 mL reaction vessel equipped with a stirrer and a reflux tube, iron complex 5 (652 mg, 1.0 mmol) synthesized from Synthesis Example 4, styrene monomer (20.8 g, 0.2 mol), azobiscyclohexanecarbonitrile (122 mg, 0.5 mmol) was added, and argon gas was blown in for 1 hour, followed by stirring at 120 ° C. for 16 hours in an argon atmosphere. The conversion rate at this time was 95% or more. When the reaction mixture was subjected to GPC analysis, Mn = 22600 and Mw / Mn = 1.22.

(Recovery of iron complex 5)
After the reaction mixture was cooled to 100 ° C., toluene (80 g) into which argon gas had been previously blown was added to dissolve the polymer. Subsequently, this toluene solution was cooled to room temperature, and air was blown in for 2 hours with stirring. At this time, the toluene solution changed from a yellow uniform solution to a brown heterogeneous solution. The solution was filtered and separated into a brown solid and a yellow solution. The obtained brown solid was washed with a small amount of toluene and then dried under reduced pressure to obtain 367 mg of brown powder. On the other hand, a yellow solution containing polystyrene was added dropwise to 800 g of methanol with stirring, and the precipitated polystyrene was separated by filtration, and then the filtrate was concentrated to obtain 290 mg of a brown solid. This was washed with methanol and diethyl ether and then dried under reduced pressure to obtain 230 mg of a brown powder. When the IR spectrum of these brown powders was measured, it almost coincided with the oxygen-bridged iron complex 6 in Example 3. The recovery rate of iron complex as oxygen bridge complex was quantitative.
The brown powder (187 mg, 0.15 mmol) and 30 mL of dehydrated methanol were added to 100 mL of Schlenk, and stirred for 30 minutes. At this time, the color of the solution was brown. To this solution, 1.2 mL (1.5 mmol) of a 1.25 mol / L hydrogen chloride methanol solution was added at room temperature and stirred overnight, resulting in a yellow heterogeneous solution. This solution was filtered, and the resulting solid was washed twice with 20 mL of diethyl ether and dried under reduced pressure to obtain 160 mg of a yellow powder. When the IR spectrum was measured, it almost coincided with the trivalent iron complex 5, and it was found that the iron complex 5 could be regenerated. (Yield 80%).

(Polymerization reaction of styrene monomer using regenerated trivalent iron complex)
A 50 mL reaction vessel was charged with the regenerated iron complex 5 obtained above (163 mg, 0.25 mmol), styrene monomer (5.12 g, 50 mmol), azobiscyclohexanecarbonitrile (30.5 mg, 0.125 mmol), After blowing argon gas for 1 hour, the mixture was stirred at 120 ° C. for 16 hours in an argon atmosphere. The conversion rate at this time was 95% or more. When the reaction mixture was subjected to GPC analysis, Mn = 23600 and Mw / Mn = 1.23.

Table 1 shows the polymerization results of styrene monomers using trivalent iron complexes before and after regeneration. As described below, even when the regenerated iron complex was used, the polymerization reaction proceeded without impairing the catalyst activity, and even when the catalyst was reused, the polymerization could be suitably performed.
(Styrene monomer: iron catalyst: radical initiator = 200: 1: 0.5 (molar ratio))

Comparison of IR spectra in Example 1 ¹ H-NMR comparison of the iron complex in Example 2 Comparison of IR spectra in Example 3 Comparison of GPC spectra in Example 3 ORTEP diagram of the iron complex (Formula 1) in Synthesis Example 3 ORTEP diagram of the iron complex (Chemical Formula 2) in Synthesis Example 3 ORTEP diagram of the iron complex (Formula 3) in Synthesis Example 4 ORTEP diagram of oxygen-bridged iron complex 5 in Example 6 Comparison of IR spectra in Example 6

Claims (17)

Iron compound represented by general formula (1)

(In the formula (1), Fe is Y-valent (Y represents an integer of 2 or 3) and X1 represents a monovalent anionic functional group). Cyclic amine compound represented

(In the formula (2), R1, R2 and R3 represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a benzyl group optionally having a substituent having 1 to 40 carbon atoms on the aromatic ring. .) In an atom transfer radical reaction using a Y-valent iron complex (Y represents an integer of 2 or 3) as a catalyst.
A method of recovering the iron complex represented by the following general formula (3) by performing the following step 1) and then step 2) after the reaction is completed.
Step 1) A step of separating the iron complex and the reaction mixture after treating the reaction mixture with oxygen, or
Step of treating the iron complex with oxygen after separating the iron complex and the reaction mixture 2) Step of treating the iron complex obtained by the above step 1) with a halogenating agent

(In the formula, Fe is trivalent, X represents a monovalent anionic functional group, and R2 and R3 are each a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or an aromatic ring having 1 to 40 carbon atoms. Represents a benzyl group optionally having a substituent. The Y-valent iron complex has the general formula (4)

(In the formula (4), Fe is divalent, X2 is a monovalent anionic functional group, R1, R2 and R3 are hydrogen atoms, hydrocarbon groups having 1 to 20 carbon atoms or carbon atoms on the aromatic ring. A benzyl group optionally having 1 to 40 substituents, An- represents an anion, and n represents an integer of 1 to 3)
The method of collect | recovering the iron complex of Claim 1 represented by these. The Y-valent iron complex has the general formula (5)

(In the formula (5), Fe is divalent, X3 is a monovalent anionic functional group, R1, R2 and R3 are carbon atoms on a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or an aromatic ring. A benzyl group optionally having 1 to 40 substituents, An- represents an anion, and n represents an integer of 1 to 3)
The method of collect | recovering the iron complex of Claim 1 represented by these. An- is represented by the general formula (6)

(In the formula (6), Fe is divalent, X4 is a monovalent anionic functional group, R1, R2 and R3 are hydrogen atoms, hydrocarbon groups having 1 to 20 carbon atoms or carbon atoms on the aromatic ring. (The benzyl group which may have 1 to 40 substituents is shown.)
Or general formula (7)

(In formula (7), X5 represents a monovalent anionic functional group, m is 0 or 1, n is 1 when m is 0, and n is 1 or 2 when m is 1. .)
The method of collect | recovering the iron complex of Claim 2 or 3 represented by these. In the general formula (1), X1 is a halogen ion, R4COO - ^(R4 is an alkyl group having 1 to 4 carbon atoms which may be substituted by a halogen atom is a hydrogen atom on a carbon atom, or a hydrogen atom on a carbon atom Represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.) And R 4 SO 3 ⁻ (wherein R 4 is a carbon atom having 1 to 4 carbon atoms in which a hydrogen atom on the carbon atom may be substituted with a halogen atom). An alkyl group or a hydrogen atom on a carbon atom represents a phenyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms), and represents any one group selected from the group represented by the general formula (2 ), R1, R2 and R3 are
1) hydrogen atom,
2) an alkyl group having 1 to 20 carbon atoms, and 3) a hydrogen atom of the aromatic ring is composed of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a polyoxyalkylene group having 1 to 40 carbon atoms. The method for recovering an iron complex according to claim 1, which shows any one group selected from the group consisting of a benzyl group optionally substituted with at least one group selected from the group. In the general formula (1), X1 is a halogen ^{ion, CH3COO -, C6H5COO -, CF3COO} -, CH3SO3 -, C6H5SO3 - and CF3 SO3 ^- indicates any one group selected from the group consisting of, in the general formula (2) , R1, R2 and R3 are
1) hydrogen atom,
2) from a group consisting of an alkyl group having 1 to 8 carbon atoms, and 3) a benzyl group in which the hydrogen atom of the aromatic ring may be substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The method for recovering an iron complex according to claim 1, which shows any one group selected. In the general formula (4), X2 is a chlorine atom or a bromine atom, R1, R2 and R3 are the same, and a group consisting of a methyl group, an ethyl group, an n-butyl group, a benzyl group and a 4-methoxybenzyl group The method for recovering an iron complex according to claim 2, wherein any one group selected from the group consisting of 1 and n is 1. In the general formula (5), X3 is a chlorine atom or a bromine atom, R1, R2 and R3 are the same, and a group consisting of a methyl group, an ethyl group, an n-butyl group, a benzyl group and a 4-methoxybenzyl group The method for recovering an iron complex according to claim 3, which represents any one group selected from the group consisting of 1 and n is 1. The method for recovering an iron complex according to claim 4, wherein in the general formula (6), X4 is a chlorine atom or a bromine atom, R1, R2 and R3 are a methyl group or an ethyl group, and n is 1. The method for recovering an iron complex according to claim 4, wherein in the general formula (7), X5 is a chlorine atom or a bromine atom, m is 1, and n is 1. The Y-valent iron complex has the general formula (8)

(In Formula (8), Fe is bivalent and R1, R2, and R3 may have a C1-C20 hydrocarbon group or a C1-C40 substituent on an aromatic ring. Benzyl group, X6 represents a monovalent anionic functional group.)
The method of collect | recovering the iron complex of Claim 1 represented by these. The Y-valent iron complex has the general formula (9)

(In Formula (9), Fe is bivalent, and R1 and R2 are benzyl optionally having a hydrocarbon group having 1 to 20 carbon atoms or a substituent having 1 to 40 carbon atoms on the aromatic ring. Group X7 represents a monovalent anionic functional group.)
The method of collect | recovering the iron complex of Claim 1 represented by these. The Y-valent iron complex has the general formula (10)

(In the formula (10), Fe is trivalent, X represents a monovalent anionic functional group, R ¹ , R ² and R ³ are a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or an aromatic group. (The benzyl group which may have a C1-C40 substituent on a ring is shown.)
The method of collect | recovering the iron complex of Claim 1 represented by these. 14. The iron complex according to claim 13, wherein R ¹ , R ² and R ^{3 in the} general formula (10) are benzyl groups having a substituent having 1 to 8 carbon atoms at the 4-position on the benzene ring. Method. The method for recovering an iron complex according to claim 14, wherein the substituent is an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a fluorinated alkyl group having 1 to 8 carbon atoms. The method for recovering an iron complex according to any one of claims 13 to 15, wherein the anionic functional group is a chlorine ion or a bromine ion. The method for recovering an iron complex according to any one of claims 1 to 16, wherein the halogenating agent is trimethylchlorosilane, hydrogen chloride, or hydrogen bromide.

Images