JP2009269905A - Method of synthesizing electroconductive polymer simple substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of synthesizing an electroconductive polymer simple substance which prepares high purity 3,4-ethylenedioxythiophene. <P>SOLUTION: The method of synthesizing an electroconductive polymer simple substance uses thioglycolic acid as an initial material and advances reactions in turn. Specifically, first, esterification, then cyclization, ring closure reaction, acidization, and decarboxylation are carried out, and without using a halogen reactant in the above ring closure reaction, an electroconductive polymer simple substance having high purity 3,4-ethylenedioxythiophene (EDT) represented by the chemical formula can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for synthesizing a single conductive polymer. In particular, the present invention relates to a method for synthesizing a single conductive polymer for producing high purity 3,4-ethylenedioxythiophene (EDT).

In 1958, Natta used an organic material containing aluminum and titanium as a catalyst, the so-called Ziegler-Natta catalyst, and polymerized acetylene gas to synthesize polyacetylene (PA). At that time, he had already discovered that this conjugated polymer had electrical conductivity, but he did not continue his research.
In the early 1970s, a Korean student, led by Dr. Hideki Shirakawa, Tokyo Institute of Technology, synthesized a silver-white cis-polyacetylene (cis-PA) film by mistakenly increasing the amount of catalyst by a factor of 1000. When this thin film is heated in vacuum or in an inert gas, cis-polyacetylene becomes gold yellow trans-polyacetylene (trans-PA). At that time he was unaware that this film could be a conductor.
In 2000, Hideki Shirakawa, American chemist Alan G. MacDiarmid, and physicist Alan J. Heeger, when polyacetylene (PA) was oxidized in iodine vapor, the conductivity of polyacetylene (PA) was significantly increased. (10 ⁹ ) was found to be nearly doubled and won the Nobel Prize in Chemistry. The three scientists made a revolutionary contribution in the discovery and development of conducting polymers, paving the way for commercialization in industry. Their research changed the general public's impression of polymers (resins) as insulators and showed that conductive polymers have both semiconductor and conductor properties. Since then, research on conducting polymers has progressed rapidly internationally and many important applications have been made.

In recent years, with the rapid development of conductive polymer materials, electronic products and information products using general metal materials are becoming more compact, thinner and lighter. Since conductive polymers have special photoelectric characteristics, their application areas are extremely wide. For example, (1) Light-emitting diode (LED), (2) Field effect transistor (FET), (3) Electrochromic, (4) Rechargeable battery, (5) Solar battery (6) Biomedical sensors, (7) Solid capacitors, (8) EMI shielding, etc.
In the last 30 years, several useful conductive polymers such as polyaniline, polypyrrolidone and polythiophene have already been developed. In the aforementioned polymers, thiophene is a simple substance of polythiophene, and it has been used relatively early, but its disadvantages are its low solubility and dark color, which is disadvantageous for processing and application. is there.

In the late 1980s, the German Bayer company (Bayer) successfully developed a new polythiophene derivative. It is poly (3,4-ethylenedioxythiophene) (PEDT). Here, 3,4-ethylenedioxythiophene (EDT) is a simple substance of poly (3,4-ethylenedioxythiophene).
Initially, it was discovered that PEDT is a high molecular weight polymer of insoluble water, but it has unique properties such as very high conductivity (300 S / cm), transparency of the thin film, and resistance to oxidation. Since PEDT and its derivatives have good conductive properties, they are widely applied in areas such as solid electrolytic capacitors, plastic antistatic coatings and photographic film coatings.

In the area of capacitors, conventional aluminum electrolytic capacitors have characteristics of liquid electrolytes and have various drawbacks. For example, (1) The amount of electricity easily changes due to the influence of ambient temperature and humidity at the time of use, so the stability is poor. (2) The capacitor degenerates depending on the usage time and has a limited service life. (3) In the capacitor There are resistance loss and dielectric loss phenomena, which consume power and generate heat, and the temperature rises, accelerating capacitor deterioration, and (4) poor high frequency characteristics and inductance For this reason, the use of this type of capacitor on high frequency circuits is limited.
Therefore, next-generation aluminum electrolytic capacitors have begun to adopt conductive polymer materials with high conductivity and excellent thermal stability as solid electrolytes, replacing the electrolyte solution in traditional aluminum electrolytic capacitors. It greatly improves the shortcomings of conventional liquid aluminum electrolytic capacitors, and exhibits extremely excellent electrical characteristics and reliability.
For example, the ripple current receiving power of a conductive polymer solid aluminum electrolytic capacitor is about 10 times that of a conventional liquid aluminum electrolytic capacitor of the same standard and is not affected by temperature. The high frequency resistance of the capacitor does not reach half that of the conventional capacitor, and at the same time has a very good service life. Therefore, the conductive polymer aluminum solid electrolytic capacitor has already become the mainstream of the development of the next generation solid electrolytic capacitor, and the conductive polymer solid capacitor is a synonym for the tip and advanced capacitor.

In 2003, US Patent No. 6,528,662 obtained by Bayer is a 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid derivatives. ) Is posted.
Here, the 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid derivative passes through thiodiacetic acid diesters and oxalic acid diesters, and 3,4-dihydroxyl derivatives. Forms thiophene-2,5-dicarboxylate (3,4-dihydroxythiophene-2,5-dicarboxylic acid esters) and uses dihaloalkanes (dichloroethane, etc.) to produce 3,4-alkylene diesters. Oxythiophene-2,5-dicarboxylic acid esters are obtained. Finally, 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid is obtained through an oxidation reaction.

  Incidentally, US Publication No. 6,369,239, acquired by Bayer in 2002, discloses a method for producing dialkylthiophenes and alkylenedioxythiophenes. Here, 3,4-dialkoxythiophene or 3,4-alkylenedioxythiophene is 3,4-dialkoxy-2,5-thiophenedicarboxylic acid or Synthesized via decarboxylation in a high boiling point solvent using 3,4-alkylenedioxy-2,5-thiophenedicarboxylic acid. The boiling point of this high-boiling solvent is higher than the product after decarboxylation (3,4-dialkoxythiophene or 3,4-alkylenedioxythiophene) and is not an aromatic amine compound.

As described above, 3,4-ethylenedioxythiophene can be manufactured by combining the manufacturing processes of the aforementioned 6,528,662 and 6,369,239 patents.
However, during the manufacturing process of the 6,528,662 patent, an intermediate product (3,4-alkylenedioxythiophene-2,5-dicarboxylate) must be made using a dihaloalkane (eg dichloroesane) . As a result, the final product (3,4-alkylenedioxythiophene-2,5-dicarboxylic acid) or its subsequent product (dialkylthiophene) may have a residual halogen reactant, which is why It is not possible to meet the toxic substance content regulations of the environmental protection regulations.
In addition, the step of producing the intermediate product using the dihaloalkane requires a reaction at a temperature of 80 to 125 ° C., and thus consumes a large amount of energy and even has a risk of causing a large explosion.
Conductive polymer simple substance (3,4-ethylenedioxythiophene, EDT) has wide material applicability, so its synthesis method is improved, its production rate and purity are secured, its experimental conditions and raw materials are improved There is a need.
US Publication No. 6,528,662 patent US Publication No. 6,369,239 Patent

The main object to be solved by the present invention is that no halogen reactant is used in the ring-closing reaction step of 3,4-ethylenedioxythiophene (EDT) production, and the entire production process is the last. In this decarboxylation reaction step, the product can be obtained only by purification by distillation, and thus the product purity can be improved.
Another object to be solved by the present invention is to perform the reaction at a relatively low temperature in the ring-closing reaction step of 3,4-ethylenedioxythiophene (EDT) production. It is an object of the present invention to provide a method for synthesizing a single conductive polymer capable of lowering the resistance and improving the operational safety.

In order to solve the above problems, the present invention provides the following method for synthesizing a single conductive polymer.
The method for synthesizing a single conductive polymer is as follows:
Thiodiglycolic acid is the initial product,
In order, esterification reaction (cyclization), ring closure reaction (ring closure reaction), oxidation reaction (acidization) and decarboxylation (decarboxylation),
In the ring-closing reaction, a conductive polymer simple substance comprising high-purity 3,4-ethylenedioxythiophene (EDT) can be obtained without using a halogen reactant.

ここで、Rはメチル基、エチル基、プロピル基或いはブチル基等のアルキル基から選択する。 In an optimal embodiment of the present invention, the method for synthesizing the conductive polymer alone includes the following steps:
Step 1: Using thiodiglycolic acid (formula I) as an initial product, esterification with alcohols to obtain thiodiglycolic acid ester (formula II),
Step 2: Cyclization of thiodiglycolic acid ester (formula II) with esters to produce dialkyl 3,4-dihydroxythiophene-2,5-dicarboxychelate , 5-dicarboxylate, formula III)
Step 3: Dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III) is converted to diisopropylazodicarboxylate (DIAD), ethylene glycol, triphenyl phosphine , Pph ₃ ) to perform a ring closure reaction to obtain 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV),
Step 4: Oxidation of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV) to produce 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (Equation V)
Step 5: Decarboxylation of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula V) yields 3,4-ethylenedioxythiophene (formula VI).

Here, R is selected from an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group.

In the following, the present invention will be described in detail with reference to an optimal embodiment.
In the method for synthesizing a single conductive polymer of the present invention, thiodiglycolic acid is an initial product, and in order, esterification, cyclization, ring closure reaction, ring closure reaction, Oxidation reaction (acidification) and decarboxylation reaction (decarboxylation) are performed to obtain a single polymer product of 3,4-ethylenedioxythiophene (EDT).

..................................(式I)

..................................(式II)
ステップ2：チオジグリコール酸エステル(式 II)とエステル類を環化反応(cyclization)させ、ジアルキル3,4-ジハイドロキチオフェン-2,5-ジカルボキレート(dialkyl 3,4-dihydroxythiophene-2,5- dicarboxylate，式 III)を得る。

..................................(式III)
ステップ3：ジアルキル3,4-ジハイドロキチオフェン-2,5-ジカルボキレート(式 III)をジイソプロピラゾジカルボキシレート(diisopropylazodicarboxylate，DIAD)、エチレングリコール(ethylene glycol)、トリフェニルホスフィン(triphenyl phosphine，Pph₃)を利用し、閉環反応(ring closure reaction)を行い、3,4-アルキレンジオキシチオフェン-2,5-ジカルボキシル酸(式 IV)を得る。

..................................(式IV)
ステップ4：3,4-アルキレンジオキシチオフェン-2,5-ジカルボキシル酸(式 IV)に対して酸化反応(acidization)を行い、，3,4-アルキレンジオキシチオフェン-2,5-ジカルボキシル酸(式 V)を得る。

..................................(式V)
ステップ5：3,4-アルキレンジオキシチオフェン-2,5-ジカルボキシル酸(式 V)に対して脱炭酸反応(decarboxylation)を行い、3,4-エチレンジオキシチオフェン(式 VI)を得る。

..................................(式VI)
ここで、R₁及びR₂はメチル基、エチル基、プロピル基或いはブチル基等のアルキル基から選択する。 More specifically, the method for synthesizing the conductive polymer alone in the optimum embodiment of the present invention includes the following steps.
Step 1: Using thiodiglycolic acid (formula I) as an initial product, esterification with alcohols is performed to obtain thiodiglycolic acid ester (formula II).

.................... (Formula I)

.................................. (Formula II)
Step 2: Cyclization of thiodiglycolic acid ester (formula II) with esters to produce dialkyl 3,4-dihydroxythiophene-2,5-dicarboxychelate , 5-dicarboxylate, formula III).

.................................. (Formula III)
Step 3: Dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III) is converted to diisopropylazodicarboxylate (DIAD), ethylene glycol, triphenyl phosphine , Pph ₃ ) to perform a ring closure reaction to give 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV).

.................... (Formula IV)
Step 4: Oxidation of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV) to produce 3,4-alkylenedioxythiophene-2,5-dicarboxyl The acid (formula V) is obtained.

.................... (Formula V)
Step 5: Decarboxylation of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula V) yields 3,4-ethylenedioxythiophene (formula VI).

.................... (Formula VI)
Here, R ₁ and R ₂ are selected from an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group.

The alcohol of step 1 is preferably selected from C ₁ -C ₄ alcohols such as methanol, ethanol, propanol, butanol and the like. The propanol is selected from n-propanol (n-propyl alcohol) or isopropanol, and butanol is linear or branched n-butanol, isobutanol or tert-butanol (tert -butanol) and the like.

The esters in Step 2 are preferably selected from C ₁ -C ₄ esters such as dimethyl oxalate, diethyl oxalate or dibutyl oxalate.
In Step 3, the ring closure reaction is preferably performed using diisopropyrazodicarboxylate (DIAD), ethylene glycol and triphenylphosphine (Pph ₃ ) at a temperature of 25 to 65 ° C.

  The step 4 is first treated with an alkaline earth metal hydroxide and then acidified with hydrochloric acid (HCl). The alkaline earth metal hydroxide is sodium hydroxide (NaOH), hydroxylated. Selection from potassium (KOH) or lithium hydroxide (LiOH) is preferred. The aqueous solution concentration of the alkaline earth metal hydroxide (such as sodium hydroxide) is preferably between about 5 to 90 wt%, and the aqueous solution concentration of hydrochloric acid is preferably between about 5 to 37 wt%.

  In step 5, decarboxylation is preferably performed using a heavy metal compound, heavy metal powder and dimethylformamide (DMF). Here, the heavy metal compound is preferably selected from copper oxide, copper carbonate, copper sulfate or copper hydroxide, and the heavy metal powder is preferably selected from copper powder.

The method for synthesizing a single conductive polymer according to the present invention will be described in detail in the following first to fifth examples, with specific details of steps 1 to 5 in order. The present invention is not limited, and the present invention can include steps 1 to 5 of other implementation modes.

Step 1 is a synthesis reaction of thiodiglycolic acid ester (formula II).
Under a nitrogen system, 75 g thiodiglycolic acid (formula I), 82.5 g butanol (BuOH) and 60 mL toluene (toluene) are placed in a three-necked flask and the condenser, oil-water separator and temperature controller are placed in the three-necked flask. Connect and start agitation. Heat to 120 ° C. and allow to flow for 18 hours to remove the resulting water. Next, it is cooled to 100 ° C., and the solvent is separated by a vacuum distillation method until the solvent is completely evaporated. Filtration and drying yields 133 g thiodiglycolic acid ester (formula II).

Step 2 is a synthesis reaction of a dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III).
Under a nitrogen system, 483 mL of methanol (CH 3 OH) is placed in a three-necked flask, cooled to 10 ° C., 44 g of sodium metal is added, and stirred at room temperature for 1 hour. Place a condenser, temperature controller, and a feeding tube in a three-necked flask, set 200 g of thiodiglycolate (formula II) and 123 g of diethyl oxalate (EtO ₂ C-CO ₂ Et) in the feeding tube, and slowly Add into a three-necked flask. Heat to 80 ° C and let it flow for 4 hours. Cool to 35 ° C, add 1.5 L of deionized water and stir for 30 minutes. Continue to lower the temperature of the three-necked flask to 10 ° C. Next, 158 mL of 37% hydrochloric acid (HCl) is placed in the additive tube and slowly added dropwise to the three-necked flask. Stir for 10 minutes and measure whether the pH value is acidic with litmus paper. It is then filtered to obtain a solid product. The product is put into 500 mL deionized water, stirred for 30 minutes, and then filtered. Next, it is dried to obtain 151 g dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III).

、52gのエチレングリコール(ethylene glycol)

と333mLのテトラハイドロフラン(tetrahydrofuran，THF)

を三ツ口フラスコ中に入れ、コンデンサー、温度制御器及び加料管を設置し、撹拌を開始する。363mLのジイソプロピラゾジカルボキシレート(diisopropylazodicarboxylate，DIAD)

を加料管に入れ、ゆっくり三ツ口フラスコ中に加える。次に40℃に加熱し、撹拌反応を24時間で継続させる。次に、室温に戻し、n-ヘキサン(n-hexane)を加え、30分間に撹拌する。ろ過後、乾燥して、644gの白色固体産物(式 IV)を得る。 Step 3 is a synthesis reaction of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV).
Under a nitrogen system, 193 g dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III), 480 g triphenylphosphine (Pph ₃ )

, 52 g ethylene glycol

And 333 mL of tetrahydrofuran (THF)

Is placed in a three-necked flask, and a condenser, a temperature controller and a additive tube are installed, and stirring is started. 363 mL of diisopropylazodicarboxylate (DIAD)

Is slowly added to a three-necked flask. It is then heated to 40 ° C. and the stirring reaction is continued for 24 hours. Next, the temperature is returned to room temperature, n-hexane is added, and the mixture is stirred for 30 minutes. Filtration followed by drying gives 644 g of a white solid product (formula IV).

Step 4 is a synthesis reaction of 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula V).
Under a nitrogen system, 215 g of white solid product and 618 mL of 10% sodium hydroxide (NaOH) solution are placed in the flask, a condenser and temperature controller are installed, stirring is started and heated to 100 ° C., 24 Circulate in time. Return to room temperature, slowly add 618 mL of 37% concentrated hydrochloric acid, and precipitate a solid until the pH value is 4 or less. The solid is filtered, washed with deionized water and dried to give 160 g of white solid product (V).

を三ツ口フラスコ中に入れ、コンデンサー及び温度制御器を設置し、撹拌を開始する。155℃まで加熱し、24時間に回流させる。室温に戻し、コンデンサー及び温度制御器を外すと、減圧蒸留設備を三ツ口フラスコに設置し、純化し、透明無色液体3,4-エチレンジオキシチオフェン(式 VI)を得る。その生産率約は53%で、ガスクロマトグラフィー(gas chromatography，GC)測定の純度は約99.67%、含水率は約0.0763%である。 Step 5 is a synthesis reaction of 3,4-ethylenedioxythiophene (formula VI).
Under a nitrogen system, 192g white solid product, 3.3g copper oxide (CuO), 2.7g copper powder (Cu) and 417mL dimethylformamide (DMF)

Is placed in a three-necked flask, a condenser and a temperature controller are installed, and stirring is started. Heat to 155 ° C and circulate for 24 hours. After returning to room temperature and removing the condenser and temperature controller, vacuum distillation equipment is placed in a three-necked flask and purified to obtain a transparent colorless liquid 3,4-ethylenedioxythiophene (formula VI). Its production rate is about 53%, the purity of gas chromatography (GC) measurement is about 99.67%, and the water content is about 0.0763%.

As mentioned above, the well-known process of the 6,528,662 patent uses a dihaloalkane to produce an intermediate product (3,4-alkylenedioxythiophene-2,5-dicarboxylate), so the product is a residual halogen reaction. There is a possibility of containing a product, and there are drawbacks such as increasing the risk to safety.
In contrast, the present invention uses diisopropyrazodicarboxylate (DIAD), ethylene glycol and triphenylphosphine (Pph ₃ ) in the ring-closing reaction step of 3,4-ethylenedioxythiophene preparation. Instead, the entire production process can be obtained simply by distillation and purification in the final decarboxylation reaction step, thus improving the product purity, and even the stricter environmental protection regulations. Meet the toxic substance content regulations. Further, the ring-closing reaction step of the present invention only needs to be carried out at a relatively low temperature, so that power consumption in the process can be reduced and operational safety can be improved.
Although the optimum embodiment has been described above, this embodiment does not limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope is based on the claims.

Claims (12)

A method for synthesizing a single conductive polymer,
Using thiodiglycolic acid (formula I) as an initial product and esterifying with alcohols to obtain thiodiglycolic acid ester (formula II);

... (Formula I)

... (Formula II)
Cyclizing a thiodiglycolic acid ester (formula II) with esters to obtain a dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III);

... (Formula III)
Dialkyl 3,4-dihydroxythiophene-2,5-dicarboxylate (formula III) is subjected to a ring-closing reaction with diisopropylamino dicarboxylate, ethylene glycol, and triphenylphosphine, and 3,4-alkylenedioxy Obtaining thiophene-2,5-dicarboxylic acid (formula IV);

... (Formula IV)
A step of oxidizing 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula IV) to obtain 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula V) When,

... (Formula V)
Decarboxylating 3,4-alkylenedioxythiophene-2,5-dicarboxylic acid (formula V) to obtain 3,4-ethylenedioxythiophene (formula VI);

... (Formula VI)
R1 and R2 are selected from alkyl groups such as methyl group, ethyl group, propyl group, or butyl group.   2. The method for synthesizing a single conductive polymer according to claim 1, wherein the alcohol for the esterification reaction is selected from methanol, ethanol, propanol or butanol.   The propanol is selected from n-propanol or isopropanol, and butanol is selected from linear or branched butanol, and the linear or branched butanol includes n-butanol, isobutanol, and tert-butanol. The method for synthesizing a single conductive polymer according to claim 2. The method for synthesizing a single conductive polymer according to claim 1, wherein esters of the cyclization reaction are selected from C ₁ -C ₄ esters. The method for synthesizing a single conductive polymer according to claim ₄ , wherein the C ₁ -C ₄ esters include dimethyl oxalate, diethyl oxalate, and dibutyl oxalate.   The method for synthesizing a single conductive polymer according to claim 1, wherein the ring closure reaction proceeds at a temperature of 25 to 65 ° C. or lower.   2. The method for synthesizing a single conductive polymer according to claim 1, wherein the oxidation reaction is first treated with an alkaline earth metal hydroxide and then reacted with hydrochloric acid.   The method for synthesizing a single conductive polymer according to claim 7, wherein the alkaline earth metal hydroxide is selected from sodium hydroxide, potassium hydroxide or lithium hydroxide.   The method for synthesizing a single conductive polymer according to claim 7, wherein the concentration of the alkaline earth metal hydroxide aqueous solution is between about 5 and 90%.   The method for synthesizing a single conductive polymer according to claim 7, wherein the concentration of the aqueous hydrochloric acid solution is between about 5 to 37%.   The method for synthesizing a single conductive polymer according to claim 1, wherein the decarboxylation reaction is carried out using a heavy metal compound, heavy metal powder, or dimethylformamide.   The method according to claim 11, wherein the heavy metal compound is selected from copper oxide, copper carbonate, copper sulfate, or copper hydroxide, and the heavy metal powder is copper powder.