JPH1045899A - Production of phenol condensate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the production of phenol condensate at a low temperature near the ambient one with high reactivity almost in no need of thermal energy by using a specific copper complex as a catalyst in the oxidative coupling reaction of phenol. SOLUTION: In the presence of (A) a copper complex of the formula [R<1> is a (substituted) hydrocarbon group; R<2> is a difunctional (substituted) hydrocarbon group; X is a counter anion; n is the number of X decided by the valences of Cu and X], (B) phenol is oxidatively coupled with (C) oxygen. In the coupling reaction, the component (A) is used in an amount of 0.01-50mol%, particularly 0.02-10mol% based on the component (B) and the polymerization is preferably carried out in a concentration of 0.5-50wt.%, particularly 1-30wt.% in the solvent at a temperature lower than 60 deg.C, particularly at 10-45 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a phenol condensate.

[0002]

2. Description of the Related Art As a method for oxidatively coupling an unsubstituted phenol with an oxidizing agent, a method using an equivalent amount of a transition metal complex as the oxidizing agent is known. For example, J. Org. Chem., 34
(8), 2388 (1969) and Inorg.Chem., 5 (5), 801 (1966)
Describes a method in which a transition metal complex oxidizing agent of vanadium tetrachloride and oxomolybdenum tetrachloride is used in an equivalent amount in the production of a phenol condensate by CC coupling. However, the method using an equivalent amount of the transition metal complex as the oxidizing agent has a problem in that the oxidizing agent is expensive and the transition metal complex generated in an equivalent amount after the reaction must be removed.

On the other hand, in the oxidative coupling of phenols, a method of using inexpensive oxygen as an oxidizing agent in the presence of a catalyst is a method excellent in mass production because water is generated from the oxidizing agent after the reaction. For example, for the oxygen oxidative polymerization of 2,6-dimethylphenol, transition metal complexes such as copper, manganese, and cobalt are already widely known as catalysts (for example, Japanese Patent Publication No. 63-6091, Japanese Patent Application Laid-Open No. No. 131627, etc.).

[0004] The catalysts used for the oxygen oxidative polymerization of unsubstituted phenols are described in JP-B-36-18692, Industrial Chemistry Magazine, Vol. 72, No. 10, 106 (1969) and JP-B-48-17395. A catalyst comprising pyridines (for example, 2,6-dimethylpyridine and the like) and a cuprous salt has been proposed, but the polymerization activity, particularly at a low temperature near normal temperature, was insufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a catalyst system having a high reaction activity at a low temperature near normal temperature in the oxygen oxidative coupling of phenol.

[0006]

Under these circumstances, the present inventors have conducted intensive studies to achieve the above object, and as a result, have obtained a transition metal complex catalyst having a specific polydentate ligand. As a result, the present invention has been completed. That is, the present invention relates to a method for producing a phenol condensate using a copper complex catalyst represented by the general formula (I) when oxidatively coupling phenol with oxygen. (Wherein, R ¹ represents a hydrocarbon group or a substituted hydrocarbon group, and all R ¹ may be the same or different. R ²
Represents a bifunctional hydrocarbon group or a substituted hydrocarbon group,
All R ² may be the same or different. X is a counter anion, and n is the number of X, which is appropriately determined by the valences of Cu and X. )

[0007]

Next, the present invention will be described in detail. (1) Copper complex catalyst The catalyst of the present invention is a copper complex catalyst represented by the above general formula (I).

The hydrocarbon group for R ¹ in the general formula (I) is preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group and an aryl group.
Ethyl group, n-propyl group, iso-propyl group, n-
Butyl, iso-butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, decyl, benzyl, 2-phenylethyl, 1-phenylethyl, phenyl, 4 -T
-Butylphenyl group, 3,5-dimethylphenyl group,
3,5-di-t-butylphenyl group, 1-naphthyl group,
And a 2-naphthyl group.

The substituted hydrocarbon group represented by R ¹ in the general formula (I) is a hydrocarbon group substituted with a halogen atom, an alkoxy group, a disubstituted amino group and the like.
Examples thereof include a trifluoromethyl group, a 2-t-butyloxyethyl group, and a 3-diphenylaminopropyl group.

As R ^{1 in the} general formula (I), a hydrocarbon group is preferable, an alkyl group having 1 to 20 carbon atoms and an aralkyl group are more preferable, and an alkyl group having 1 to 20 carbon atoms is more preferable.

The bifunctional hydrocarbon group represented by R ² in the general formula (I) is preferably an alkylene group having 1 to 20 carbon atoms, an arylalkylene group, a cycloalkylene group or an arylene group. , Methylene group, 1,2-ethylene group, 1,2-propylene group, 1,
3-propylene group, 2,4-butylene group, 2,4-dimethyl-2,4-butylene group, 1,2-diphenyl-1,
2-ethylene, 1,2-cyclopentylene group, 1,2-
Cyclohexylene group, 1,2-phenylene group, 4,5-
Examples thereof include a dimethyl-1,2-phenylene group and a 2,3-naphthylene group.

The bifunctional substituted hydrocarbon group represented by R ² in the general formula (I) is a difunctional substituted hydrocarbon group substituted with a halogen atom, an alkoxy group, a disubstituted amino group, or the like. Examples are 1,1,2,2-tetrafluoro-1,2-ethylene groups, 4,5-dimethoxy-1,
Examples thereof include a 2-phenylene group and a 4-dimethylamino-1,2-phenylene group.

R ^{2 in the} general formula (I) is preferably a bifunctional hydrocarbon group, more preferably an alkylene group having 1 to 20 carbon atoms and a cycloalkylene group, and more preferably an alkylene group having 1 to 20 carbon atoms. Groups are more preferred.

The valence of Cu in the above general formula (I) is monovalent or divalent, preferably divalent.

In the general formula (I), X is a counter anion, and n is the number of X, and is determined by the valence of Cu and X. The counter anion is not particularly limited, but a conjugate base of Bronsted acid is usually used. Specific examples thereof include fluoride ion, chloride ion, bromide ion, iodide ion, sulfate ion, nitrate ion, and carbonate ion. , Perchlorate, tetrafluoroborate, hexafluorophosphate, methanesulfonate, trifluoromethanesulfonate, toluenesulfonate, acetate, trifluoroacetate, propionate, benzoate, water Oxide ions, oxide ions, methoxide ions, ethoxide ions and the like can be mentioned. Preferably, chloride ion, bromide ion, sulfate ion,
It is a nitrate ion or an acetate ion, more preferably a chloride ion or a bromide ion.

In the copper complex of the present invention, the structure other than the above is not particularly limited as long as the catalytic activity is not deactivated. In the copper complex catalyst of the present invention, a solvent or the like may be coordinated in the raw material of the complex, the synthesis process and / or the oxidative coupling reaction process.

The copper complex of the present invention can be synthesized by, for example, a method of mixing a tridentate ligand compound and a copper compound in an appropriate solvent. Such copper compounds include:
A Bronsted acid salt of copper or the like is appropriately used. Further, the tridentate ligand compound is described in J. Chem. Soc. Dalton Trans., 83
(1993). And J. Am. Chem. Soc., 8865, 117 (1995). As the copper complex, a complex synthesized in advance can be used, but the complex may be formed in a reaction system.

In the present invention, the catalysts can be used alone or as a mixture. In the present invention, the catalyst can be used in any amount, but generally, the amount of the copper complex to phenol is preferably 0.01 to 50 mol%, more preferably 0.02 to 10 mol%.

(2) Oxidative Coupling Reaction In the present invention, oxygen is used as the oxidizing agent. Oxygen may be a mixture with an inert gas or air. The amount of oxygen used is usually greater than or equal to the amount of phenol in a large excess.

Although the reaction of the present invention can be carried out in the absence of a reaction solvent, it is generally preferable to use a solvent. The solvent is not particularly limited as long as it is inert to phenol and liquid at the reaction temperature. Preferred examples of the solvent include aromatic hydrocarbons such as benzene, toluene and xylene; linear and cyclic aliphatic hydrocarbons such as heptane and cyclohexane; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene and dichloromethane; acetonitrile , Nitriles such as benzonitrile; alcohols such as methanol, ethanol, n-propyl alcohol and isopropyl alcohol;
Ethers such as dioxane, tetrahydrofuran and ethylene glycol dimethyl ether; amides such as N, N-dimethylformamide and N-methylpyrrolidone; nitro compounds such as nitrotan and nitrobenzene; and water. More preferred are aromatic hydrocarbons and halogenated hydrocarbons. These are used alone or as a mixture.

When the solvent is used, the phenol concentration is preferably 0.5 to 50% by weight, more preferably 1 to 50% by weight.
It is used in such a ratio that it becomes 30% by weight.

When the copper complex has a conjugate base of an acid stronger than phenol as a counter ion, a base which does not inactivate the copper complex catalyst may coexist with the counter ion in an equivalent amount or more during the reaction. preferable. Examples of such bases include hydroxides, oxides, alkoxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, calcium oxide, sodium methoxide, sodium ethoxide; methylamine, ethylamine, Propylamine, butylamine,
Amines such as dibutylamine and triethylamine; and pyridines such as pyridine, 2-methylpyridine, 2,6-dimethylpyridine and 2,6-diphenylpyridine. Usually, amines and pyridines are often used.

The reaction temperature for carrying out the present invention is not particularly limited as long as the reaction medium is kept in a liquid state, but is preferably lower than 60 ° C. in order to reduce the energy required for heating. ℃ is more preferable, 10-45 ℃
Is more preferred.

[0024]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited by these examples.

Phenol conversion (Conv.): 15 m of reaction mixture containing diphenyl ether as internal standard
g, acidified by adding a small amount of concentrated hydrochloric acid,
2 g of methanol was added to obtain a measurement sample. This sample was subjected to high performance liquid chromatography (pump: Waters 600E system, detector: Waters UV / VIS-486, detection wavelength: 278 nm, column: YMC ODS-AM, developing solvent: methanol /
Water = Start from 50:50 and 100/0 after 25 minutes
, And then kept for up to 45 minutes), and quantified using diphenyl ether as an internal standard.

Number average molecular weight (Mn), weight average molecular weight (Mw) of the polymer: gel permeation chromatography (pump: 600E system manufactured by Waters, detector: UV / VIS-484 manufactured by Waters, detection wavelength: 254 nm) , Column: Ultrastyra manufactured by Waters
gel Linear = 2 + 1000A = 1 + 100A = 1
(Developing solvent: chloroform), and the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured in terms of standard polystyrene.

REFERENCE EXAMPLE 1 The copper complex catalyst used in this example was obtained from J. Chem. Soc. Dalton
Trans., 83 (1993). That is, 1,4
7-Triazacyclononane is reacted with isopropyl bromide in toluene in the presence of potassium hydroxide at 80 to 90 ° C., and then sodium perchlorate is added to add 1,4,7-triisopropyl-1,4,7. -Crystals of the perchlorate of triazacyclononane were obtained. After neutralizing 0.3 g of the perchlorate with potassium hydroxide in toluene, the solvent was distilled off under vacuum. In this, acetone 15mL, Cu
0.15 g of Cl ₂ .2H ₂ O (equivalent to the perchlorate of the ligand) and 20 mL of methylene chloride are added.
Stirred for hours. After completion of the reaction, the solvent was distilled off under vacuum, dissolved in a mixed solvent of methylene chloride / tetrahydrofuran, filtered and desalted. The solvent was further distilled off under vacuum, and recrystallized from octane / methylene chloride. Complex (hereinafter referred to as Cu
(tacn). ) Got.

Example 1 A rubber balloon filled with oxygen was attached to a 25 ml two-necked round bottom flask equipped with a magnetic stirrer, and the inside of the flask was replaced with oxygen. Add 0.020 mmol of Cu (tacn) to this,
0.80 mmol of phenol and 0.20 mmol of 2,6-diphenylpyridine as a base are added to 0.80 mmol of toluene.
g was added. While stirring the contents, the flask was kept warm in a 40 ° C. water bath and reacted for 30 hours. After the reaction was completed, a few drops of concentrated hydrochloric acid were added to make the mixture acidic, and then 20 ml of methanol was added, and the precipitated polymer was collected by filtration. The polymer was washed three times with 10 ml of methanol, three times with 10 ml of ion-exchanged water, three times with 10 ml of methanol, and dried under reduced pressure at 100 ° C. for 5 hours to obtain a polymer.
After 30 hours at 40 ° C., the conversion of phenol (Con
v.) was 37%, and the yield of the polymer was 33%. Also,
The molecular weight of the polymer was determined based on the Mw of chloroform-soluble part.
= 16900 and Mn = 3300.

Comparative Example 1 A rubber balloon filled with oxygen was attached to a 25 ml two-necked round bottom flask equipped with a magnetic stirrer, and the inside of the flask was replaced with oxygen. To this, 0.030 mmol of cuprous chloride was added, and 0.030 mmol of 2,6-dimethylpyridine and 1.20 mmol of phenol dissolved in 1.2 g of toluene were added. While stirring the contents,
The mixture was kept warm in a water bath at 0 ° C. and reacted for 33 hours.
After the reaction was completed, a few drops of concentrated hydrochloric acid were added to make the mixture acidic, and then 20 ml of methanol was added, and the precipitated polymer was collected by filtration. Washed 3 times with 10 ml of methanol, 3 times with 10 ml of ion-exchanged water, 3 times with 10 ml of methanol, 100 times
After drying under reduced pressure at 5 ° C. for 5 hours, a polymer was obtained. 40 ° C, 3
After 3 hours, the conversion of phenol (Conv.) Was 13
%, And the yield of the polymer was 11%. The molecular weight of the polymer was Mw = 20900 and Mn = 4800.

[0030]

As described above, in the oxygen oxidative coupling of phenol, the catalyst system of the present invention has a much higher reaction activity at a low temperature near normal temperature than the conventional catalyst system, and the heat energy for keeping the temperature warm. Is almost unnecessary.

Claims (2)

[Claims] 1. A process for producing a phenol condensate using a copper complex catalyst represented by the general formula (I) when oxidatively coupling phenol with oxygen. (Wherein, R ¹ represents a hydrocarbon group or a substituted hydrocarbon group, and all R ¹ may be the same or different. R ²
Represents a bifunctional hydrocarbon group or a substituted hydrocarbon group,
All R ² may be the same or different. X is a counter anion, and n is the number of X, which is appropriately determined by the valences of Cu and X. ) 2. The method for producing a phenol condensate according to claim 1, wherein the reaction temperature at the time of oxidative coupling of phenol with oxygen is lower than 60 ° C.