JPH0229430A - Production of furan polymer - Google Patents

Abstract

PURPOSE:To produce an org. solvent-soluble high-MW furan polymer without using any catalyst safely and easily, by reacting a specific furan compd. with a specific alkali metal compd. in an org. solvent in the absence of water and then in an O2 atmosphere. CONSTITUTION:A furan compd. of formula I (wherein R is H, alkyl, phenyl or alkyl-substd. phenyl; each of X<1> and X<2> is H or halogen) (e.g., furan, 3- methylfuran etc.) is reacted with an alkali metal compd. of formula II(wherein R<1> is alkyl, phenyl or alkyl-substd. phenyl; M is an alkali metal) (e.g., n- butyllithium, sec-butyllithium etc.) in an org. solvent and substantially in the absence of water and then in an O2 atmosphere to give a furan polymer. By this method a high-MW furan polymer is safely and easily obtd. without using any catalyst.

Description

[Detailed description of the invention] The present invention relates to a method for producing furan-based polymers.

[Conventional technology]

Recently, research on conductive materials made of organic polymers such as polyacetylene and polypyrrole has been actively conducted. Since furan has a similar structure to thiophene, it can be assumed that it becomes a conductive material when polymerized, but polyfurans with excellent conductivity have not been reported.

Eur, Polym, J, Vo123, No9, 7
19-722 (1987) K describes a polymerization method in which furan is reacted with iodine or bromine in a nitrogen atmosphere.
The polymer obtained by this method was a complex of iodine and bromine, a brittle film, and insoluble in solvents.

[Problem to be solved by the invention]

An object of the present invention is to provide a method for chemically polymerizing furan compounds, particularly a method for producing soluble furan polymers.

Examples of organic solvents used in the present invention include ether solvents such as ethyl ether, methyl phenyl ether, and tetrahydrofuran, benzene, toluene, ethyl acetate, hexane, cyclohexane, and petroleum ether. Ether solvents having excellent reactivity with alkali metal compounds shown in are preferably used.

If the organic solvent contains water, the alkali metal compound represented by general formula (II) reacts with water and loses reactivity, so the organic solvent is used in a substantially water-free state.

The furan compound used in the present invention is a compound represented by the general formula (I), where Rii represents a hydrogen atom, an alkyl group, a phenyl group, or an alkyl-substituted phenyl group, and Xi and x2 represent a hydrogen atom or a halogen atom. Indication: Xi and x2 may be the same or different.

Incidentally, examples of the halogen atom include chlorine, chlorine, bromine and iodine, with bromine and iodine being preferred.

Examples of the above-mentioned furan compounds include furan, 3-methylfuran, 3-phenylfuran, 2.5-dibromofuran, 2.5-dibromo-3-methylfuran, 2.5-
Examples include dibromo-3-phenylfuran.

The alkali metal compound h used in the present invention is represented by the general formula (formerly R1.M...(n), in which RI Fi is an alkyl group, a phenyl group, or an alkyl-substituted phenylfuran, and M Vi is an alkali Indicates a metal.The above alkyl group preferably has 10 or less carbon atoms, such as methyl, ethyl, n-7'
Examples include groups such as lobil, tso-7'pyl, n-butyl, 5ec-butyl, n-pentyl, n-hexyl,
More preferred are ethyl, n-propyl, 1so-propyl, n-butyl, and 1so-butyl groups, and as the alkyl-substituted phenyl group, phenyl groups substituted with carbon & 10 or less alkyl groups are preferred. Examples include methylphenyl, dimethylphenyl, and ethylphenyl groups. Further, examples of the alkali metal include lithium, sodium, caritum, etc., and Vin-butyrrhizicum and 5ec-butyrrhizicum are preferable as the alkali metal compound.

In the present invention, first of all, the above-mentioned furan compound (I
) and the alkali metal compound (II) are reacted in an organic solvent substantially in the absence of water.

The furan compound (I) and the alkali metal compound (II) melt and undergo an anionization reaction to form an anion intermediate, and this intermediate undergoes a polymerization reaction in an oxygen atmosphere to form a furan polymer. It is preferable to carry out the polymerization in an oxygen atmosphere after the completion of the anionization reaction, since the yield will be higher and a polymer with a higher molecular weight will be obtained if the polymerization reaction is carried out afterwards.

Incidentally, the above anionization reaction Fi is preferably carried out at a low temperature,
More preferably Vi-70°C to 10°C. Moreover, it is preferable to carry out the polymerization reaction Fi at a temperature of -10°C to 50°C. Although the anionization reaction may be carried out in any atmosphere, it is preferably carried out under an inert gas atmosphere, more preferably under a nitrogen atmosphere, so that side reactions may proceed.

The addition amount of the furan compound (I) and the alkali metal compound (II) is such that if the addition amount of the alkali metal compound (11) is small, the amount of anions produced will be small, making it difficult to obtain a high molecular weight furan polymer. On the other hand, when the amount increases, polyvalent anions are formed and side reactions proceed more easily, making it easier to obtain by-products and low molecular weight furan-based polymers. Since it is easily deactivated, the alkali metal compound (II) is preferably added in an amount of α5 to 5.0 equivalents, more preferably Fito to 3.0 equivalents, relative to the furan compound (I).

〔Effect of the invention〕

The method for producing a furan-based polymer of the present invention is as described above, and a high-molecular-weight furan-based polymer can be obtained safely and easily without using a catalyst.

The obtained furan-based polymer is soluble in organic solvents and can be easily molded. Furan-based polymer moldings have an affinity for electron acceptors such as iodine, sulfur trioxide, sulfuric acid, tetracyanoquinodimethane, and tetracyanoethylene, and they strongly adsorb these electron acceptors. By adsorption, an excellent organic polymer semiconductor can be easily obtained.

〔Example〕

Next, the present invention will be explained in detail.

Example 1 Furan 39 (44 mmol) and dry ethyl ether 60- were supplied to a Yotsuro flask, and while stirring at θ°C in a nitrogen stream, a hexane solution of 5ee-butyrrhizicum (1
48 mol/V) (50 mmol of see-butyrrhizicum) was added dropwise over 15 minutes, and after the addition, the reaction was continued for 2 hours to obtain a deep yellow reaction solution.

Next, oxygen was injected into the flask, and the resulting reaction solution was reacted in an oxygen atmosphere for 2 hours to obtain a black-red reaction solution. Add tetrahydrofuran and toluene to the resulting reaction solution,
After washing with water, the water was removed with anhydrous sodium sulfate, and the solvent was removed with a rotary evaporator to obtain a black product. The obtained product was reprecipitated with tetrahydrofuran and hexane to obtain a black solid L03.

The obtained black powder was soluble in tetrahydrofuran and dimethyl sulfoxide, and its molecular ffi was about 5,000 when its GPc spectrum was measured. (Polystyrene equivalent) Even when the black solid was exposed to air at 25° C. for one month, there was no change in the GPC spectrum and infrared absorption spectrum.

Table 1 also shows the elemental analysis values of the black solid.

The obtained black solid was fed to an infrared molder and heated at 2400
The electrical conductivity of the molded product obtained by molding at a pressure of Kg/cd was measured to be 10/4S/6R at 25°C. The obtained molded product was exposed to iodine vapor at 80° C. for 3 days to obtain a molded product doped with 230% by weight of iodine. The electrical conductivity of this molded body is 9.8 x 10 at 25°C.
'It was in S/a1.

Example 2 sec-Butyrrhizicum hexane solution (t48 mol
/l 65i (5ec-Putylrichicum 97 dishes 1)
A black solid of L459 was obtained in the same manner as in Example 1 except that the solution was added dropwise over 15 minutes. When the obtained black powder was measured by GPC spectrum, the molecular weight was approximately 10.0.
It was 00. (Polystyrene equivalent) Elemental analysis values Fi are shown in Table 1. In addition, when the electrical conductivity was measured in the same manner as in Example 1, L at 25°C.
4 x 10'-'' S/(!II.The obtained molded body was exposed to iodine vapor at 80°C for 3 days to obtain a molded body doped with 260% by weight of iodine. The electrical conductivity was 9.8×10 S/unit at 25°C.

Table 1 (Note) Value obtained by subtracting C and H from the value of O Fi100 Example 3 Hexane solution of n-butyrrhizicum (148 mol /
l) 36ml! A black powder of α88F was obtained by pressing in the same manner as in Example 1, except that . (
Polystyrene equivalent) Example 4 Hexane solution of n-butyrrhizicum (L48 mol/l
) Black powder of (L95) was obtained in the same manner as in Example 1 except that 66 me was added dropwise, and the molecular weight was #i2.000 when measured by GPC Svetator.

(Polystyrene conversion 1v-)

Claims (1)

[Claims] 1. In an organic solvent, substantially in the absence of water, the general formula (
There are furan compounds represented by I) and ▲mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I) (In the formula, R represents a hydrogen atom, an alkyl group, a phenyl group, or an alkyl-substituted phenyl group, X^1 and X^2 represent hydrogen atoms or halogen atoms.) Alkali metal compound R^1 represented by general formula (II)
After reacting M... (II) (in the formula, R^1 represents an alkyl group, a phenyl group, or an alkyl-substituted phenyl group, and M represents an alkali metal), further under an oxygen atmosphere. A method for producing a furan-based polymer, which comprises reacting it.