JPH0415813B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing poly-nuclear alkoxy-substituted p-phenylene vinylene by desulfonium salt treatment of a polymeric sulfonium salt.

In general, conjugated polymers are insulators or semiconductors as they are, and high conductivity cannot be obtained.However, in recent years, starting from the discovery that doping polyacetylene to develop metal conductivity, various conjugated polymers have been developed. Attempts have been made to improve conductivity by doping polymeric compounds with appropriate electron acceptors or electron donors. However, many of these conjugated polymers are generally infusible and insoluble as they are, making them difficult to mold and process, which poses a major obstacle to their practical application.

Poly-nuclear alkoxy-substituted-p-phenylene vinylene is known as a linear conjugated polymer, and its production methods include the witting reaction method, which involves the reaction of a diphosphonium salt with a dialdehyde, or the alkali reaction of a nuclear alkoxy-substituted xylylene dihalide. It is known that it can be synthesized by dehydrohalogenation method etc.

However, the polymers obtained by these synthesis methods are thought to have a degree of polymerization of 10 or less, and since they are produced in the form of insoluble and infusible powders, it is virtually impossible to form them into a film or thread as they are. This was impossible, and no useful molded product could be obtained even using a special powder molding method.

The present inventors have intensively investigated the possibility of obtaining a conjugated polymer that can be processed into any desired shape and that can be doped to provide high conductivity. The inventors have discovered that this object can be achieved by the following methods, and have arrived at the present invention.

That is, as a result of studying various production methods for obtaining poly-nuclear alkoxy-substituted-p-phenylene vinylene, the present inventors found that poly-nuclear alkoxy-substituted-p-phenylene vinylene
- A polymeric sulfonium salt is produced by condensation polymerization of a disulfonium salt of xylylene dihalide using an alkali, and after shaping this polymeric intermediate, it is treated with a desulfonium salt to produce a poly-
We have discovered a method for producing nuclear alkoxy-substituted -p-phenylene vinylene.

Furthermore, the poly-nuclear alkoxy-substituted-p-phenylene vinylene produced in this way is
It has also been found that it is possible to produce products with extremely high molecular weights compared to those produced by the wittig method or dehydrohalogenation method, and that significantly higher conductivity can be imparted by doping.

The fact that a polyphenylene vinylene structure can be created by the sulfonium salt decomposition method in this way is explained by J. Polymer.
Sci., A-1. 6 . 1058 (1968) etc., but
Nothing was known about poly-nuclear alkoxy-substituted p-phenylene vinylene in which the phenyl group contains an alkoxy substituent, its production method, and its electrical conductivity.

That is, the present invention is based on the general formula () R: Alkyl group having 1 to 6 carbon atoms R ₂ , R ₃ : Hydrocarbon group having 1 to 10 carbon atoms The object of the present invention is to provide a method for producing poly-nuclear alkoxy-substituted p-phenylene vinylene by processing.

-OR in the general formula () indicates that the benzene nucleus is substituted with an alkoxy group.

R of the alkoxy group is a hydrocarbon group having 1 to 6 carbon atoms, such as an alkyl group such as methyl, ethyl, isopropyl, t-butyl, cyclopentyl, 2-ethyl-hexyl group, phenyl group and its derivatives, etc. The ethyl group, especially the methyl group, is preferred.

R ₂ and R ₃ are hydrocarbon groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, 2-ethylhexyl, dodecyl, oketadecyl, phenyl, cyclohexyl, benzyl groups, etc. 1 to 6 hydrocarbon groups, particularly methyl and ethyl groups are preferred.

Any counter ion X of the sulfonium salt can be used in a conventional manner. For example, halogens, hydroxyl groups, boron tetrafluoride, perchlorate ions, etc. can be used, and among them, halogens such as chlorine, bromine, and iodine and hydroxyl ions are preferred.

The polymeric sulfonium salt used in the present invention can be obtained by any method, but for example, a nuclear alkoxy-substituted -p-xylylene dihalide obtained by reacting a nuclear alkoxy-substituted -p-xylylene dihalide with a dialkyl sulfide can be used.
-The xylylene disulfonium salt can be obtained by condensation polymerization using an alkali in water or a water-soluble organic solvent such as a mixed solvent of alcohols. Further, by coexisting another type of p-xylylene disulfonium salt and similarly performing condensation copolymerization with an alkali, a polymeric sulfonium salt containing a structural unit of phenylene vinylene substituted with nuclear alkoxy can be obtained. Any of these can be used as the polymeric sulfonium salt of the present invention.

The alkaline solution used for condensation polymerization is preferably an organic solvent that does not react with water or sulfonium salts, such as a strongly basic solvent with a pH of 11 or higher in a mixed solvent of alcohols and water, such as sodium hydroxide, potassium hydroxide, water, etc. Calcium oxide, quaternary ammonium salt hydroxide, sulfonium salt hydroxide, strongly basic ion exchange resin (OH type), etc. can be used, but sodium hydroxide, potassium hydroxide, and strongly basic ion exchange resin are preferable. Can be used for In order to obtain a highly conductive molded product, it is preferable that the molecular weight is sufficiently large, and n is at least 5 or more, preferably 5 to 50,000. Things are used effectively.

According to the method of the present invention, a high molecular weight sulfonium salt can be obtained.

A feature of the present invention is that molded articles of arbitrary shapes can be made from polymeric sulfonium salts, especially solutions thereof.

The sulfonium salt used in the present invention is sensitive to heat, light, ultraviolet rays, strong basic conditions, etc., and desulfonium salts gradually occur and tend to become polymeric sulfonium salts with a partially conjugated structure, which may result in heterogeneity. be. Therefore, it is preferable to process quickly at a relatively low temperature, that is, at a temperature of at least 50° C. or lower, particularly 25° C. or lower, and to use a homogeneous polymeric sulfonium salt during processing.

Any method can be used to obtain a polymer molded article from a polymer sulfonium salt. Regarding its form, for example, a film, thread, coated material, or any other molded product can be selected. Particularly useful forming methods are casting or solution spinning from sulfonium salt synthesis aqueous solutions or other media solutions. At this time, it is preferable to use a polymer sulfonium salt solution that has been desalted or unreacted substances removed by dialysis treatment or the like.

Desulfonium salt treatment for sulfonium salts is
This can be carried out by applying conditions such as heat, light, ultraviolet rays, strong base treatment, etc., but heat treatment is preferred. In order to obtain a highly conductive composition, it is important to carry out the desulfonium salt treatment of the polymeric sulfonium salt in an inert atmosphere. The inert atmosphere here refers to an atmosphere that does not cause deterioration of the polymer film during processing, and it is particularly necessary to prevent oxidation reactions due to oxygen and air.

This is generally carried out using an inert gas such as nitrogen, argon, helium, etc., but it may also be carried out under vacuum or in an inert medium.

When desulfonium salt treatment is carried out by heat, the treatment temperature is 0°C to 300°C, preferably 50°C.
~250℃ is suitable. More preferably 100℃~200℃
It's in °C.

Alternatively, the molded product can be stretched and oriented and heat treated. These stretching and orientation treatments can be performed before or simultaneously with the desulfonium salt treatment. Orientation can be achieved by devising a molding method, such as extrusion using high shear force, but high orientation can be imparted by stretching a molded product made from a sulfonium salt solution.

This stretching orientation is an extremely important operation in order to obtain high conductivity.

The poly-nuclear alkoxy-substituted p-phenylene vinylene obtained according to the present invention can be doped with an electron acceptor or an electron donor to give a highly conductive composition. As the electron acceptor or electron donor here, it is effective to use compounds that have been found to have the effect of improving conductivity by doping conventional conductive polymer compounds such as polyacetylene, or by forming an interlayer compound of graphite. used for.

The composition of the present invention can be obtained by any method, but it is preferably doped by conventionally known methods such as chemical doping, electrolytic doping, optical doping, and ion implantation.

Specifically, electron acceptors include halogen compounds: fluorine, chlorine, bromine, iodine, iodine chloride, iodine trichloride, iodine bromide, iodine pentafluoride Lewis acids: phosphorus pentafluoride, arsenic pentafluoride , antimony pentafluoride, boron trifluoride, boron trichloride, boron tribromide, sulfur trioxide Protonic acids: hydrogen fluoride, hydrogen chloride, nitric acid, sulfuric acid, perchloric acid, fluorinated sulfonic acid, chlorinated sulfonic acid, Methanesulfonic trifluoride Transition metal chlorides: titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, niobium pentachloride,
Tantalum pentachloride, molybdenum pentachloride, tungsten hexachloride, iron trichloride Organic compounds: tetracyanoethylene, tetracyanoquinodimethane, chloranil, dichlorodicyanobenzoquinone Alkali metals as electron donors: lithium, sodium, potassium, Examples include rubidium, cesium quaternary ammonium salts: tetraalkylammonium ions, and the like.

The preferred content of the doping reagent varies depending on the type of doping reagent, but can generally be changed arbitrarily depending on doping conditions such as doping time and doping reagent concentration. In general, the preferred content is 0.01 to 0.3 moles of dopant relative to the CH- unit involved in the conjugated system; if the mole number is small, high conductivity will not be achieved, and if the mole number is large, the electric conductivity will be saturated. It is not economical because it has a tendency. Among these doping agents, dopants that do not react with the conjugated bond formed and the dialkoxy substituent are preferred because they provide a highly conductive composition. Particularly effective doping agents include anhydrous or fuming sulfuric acid and iodine.

The polynuclear alkoxy-substituted p-phenylene vinylene obtained according to the present invention can provide a composition with a high conductivity of 100 S/cm or more when iodine, which has a particularly weak oxidizing power, is used as a dopant.

What should be noted here is that the poly-nuclear alkoxy-substituted-p-phenylene vinylene obtained in this way or the copolymer mainly composed of this structural unit can be produced by doping, resulting in a poly-p-phenylene vinylene having no substituents.
- It has been discovered that the conductivity is significantly improved compared to phenylene vinylene.

Although the reason is still speculative, it is thought that the electron-donating alkoxy group is incorporated into the conjugated polymer, lowering the ionization potential of the polymer and making it easier to complex with the dopant.

Furthermore, the poly-nuclear alkoxy-substituted-p-phenylene vinylene obtained in the present invention has surprisingly good oxidation stability and is extremely preferred as a conductive material.

Poly-nuclear alkoxy-substituted-p obtained in the present invention
- By combining phenylene vinylene with a doping agent, it can be applied to various electrical and electronic materials utilizing conductivity, and its uses are not particularly limited.

The present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 After dissolving 3.6 g of 2,5-dimethoxy-P-xylylene bis(dimethylsulfonium bromide) in 50 ml of ion-exchanged water, 50 ml of 0.3N NaOH aqueous solution was added dropwise at 0 to 5°C over 15 minutes. 0
Stirring was continued for 30 minutes at ~5°C. 0.77 regulation after reaction
The mixture was neutralized using an aqueous HBr solution, and 0.77N HBr was added to the equivalent amount of NaOH.

This reaction solution was subjected to dialysis treatment for one day using a dialysis membrane (Cerotube, molecular weight fraction: 8000).

Cast this liquid and dry it under reduced pressure at below 40℃.
A polymeric sulfonium salt film having a pale red sulfonium salt in its side chain and having a thickness of 3 μm was obtained.

This film (length 5 cm, width 3 cm) was heated in a horizontal tube furnace at 200°C for 30 minutes in a nitrogen atmosphere to form a film of poly-2,5-
Dimethoxyphenylene vinylene was obtained.

This structure was confirmed by elemental analysis and characteristic absorption in the infrared absorption spectrum, which matched that of the specimen obtained by the dehydrohalogenation method.

Reference Example 1 When the poly-2,5-dimethoxyphenylenevinylene film obtained in Example 1 was doped from the gas phase at room temperature using iodine as an electron acceptor compound, 18 In time
It showed an electrical conductivity of 155S/cm. (Measurement of conductivity is 4
It was done using the terminal method. ) 4 in the air after doping
The conductivity of the sample left for one day was 11 S/cm.

Reference example 2 Poly-2,5-dimethoxy-p obtained in Example 1
- When a phenylene vinylene film was doped using 30% oleum as a source of sulfuric anhydride, the conductivity was 10.3 S/cm.

Reference Example 3 A polymer sulfonium salt film obtained by the method described in Example 1 was cast and heated at 200°C under a nitrogen atmosphere.
The film obtained by heating for 30 minutes is used as an electrolyte.
When electrolytic doping was performed using a 0.5N LiclO ₄ -propylene carbonate solution, the resulting film was glossy black and had an electrical conductivity of 53S/
It was cm.

Example 2 1.5 gr of 2,5-diethoxy-p-xylylenebisdiethylsulfonium bromide was dissolved in 50 ml of a mixed solvent of distilled water and ethanol (weight ratio 1:2), and then cooled to 0°C. Next, a strongly basic ion exchange resin (Amberlite
1RA-401) gradually over 10 minutes at 0-5℃.
Continue stirring for 100 minutes.

After the reaction, the ion exchange resin was removed by filtration, and the filtrate was subjected to dialysis treatment at 0°C to 5°C using a dialysis membrane (Cerotube molecular weight fraction 3500). This liquid was cast and dried under reduced pressure at 30°C for 24 hours.

The obtained polymeric sulfonium salt film was heated and stretched at up to 200°C under nitrogen flow.
Double-stretched poly-2,5-diethoxy-p-
A phenylene vinylene stretched film was synthesized.

Reference Example 4 The poly-2,5-diethoxyphenylenevinylene film obtained in Example 2 was doped with iodine by a conventional method, and the electrical conductivity was measured to be 71 S/cm for a double stretched film. .

Claims (1)

[Claims] 1. General formula R: Alkyl group having 1 to 6 carbon atoms R ₂ , R ₃ : Hydrocarbon group having 1 to 10 carbon atoms 1. A method for producing poly-nuclear alkoxy-substituted p-phenylene vinylene, which comprises carrying out a desulfonium salt treatment in an active atmosphere.