TWI621641B - Method for synthetic oligo-aniline - Google Patents

Abstract

A method for synthesizing an aniline oligomer, firstly preparing a first brine solution and a second brine solution; then adding a first aniline compound and a second aniline compound to the first brine solution to form a mixture of aniline compounds Next, an oxidizing agent is dissolved in a second brine solution to form an aqueous oxidizing agent solution; then an aqueous oxidizing agent solution is added to the aniline compound mixture to react the first aniline compound with the second aniline compound to form a monoaniline oligomer.

Description

Method for synthesizing aniline oligomer

The present invention relates to a method of synthesis, and more particularly to a method of synthesizing an aniline oligomer.

In general, since organic conductive polymers have both the properties of conductive materials and polymer materials, many scientists have conducted research on conductive polymers in recent years. Among them, polyaniline itself has a reversible doping property and conductivity, so it can be applied in a wide range of fields; however, polyaniline has a poor solubility due to the large molecular weight of its own polymer, so many scientists have prepared it. An aniline oligomer having an electroactive chain end, thereby increasing solubility and being electrically active.

According to the above, since the polymerization of polyaniline is mainly polymerized under a strong acid environment, the prior art also prepares an aniline by using an oxidative coupling method in the preparation of an aniline oligomer. Oligomers, but since the yield is only up to about 40%, and it usually takes 4 to 8 hours to carry out the reaction, the aniline oligomer cannot be efficiently produced.

In view of the prior art, the preparation method of aniline oligomers mainly takes a large amount of time to prepare aniline oligomers by using oxidative coupling in a strong acid environment, and the yield is only up to 40%, but A large amount of acidic waste liquid is produced; thus, it is an object of the present invention to provide a method for synthesizing an aniline oligomer to improve the yield of an aniline oligomer by utilizing a change in synthesis conditions.

In order to achieve the above object, the present invention provides a method for synthesizing an aniline oligomer, comprising the steps of: first step (a) is to prepare a first brine solution and a second brine solution; and step (b) is to construct a structure. a first aniline compound represented by the formula (1) and a second aniline compound represented by the formula (2) are added to the first brine solution to form a mixture of aniline compounds,

Next step (c) is to dissolve an oxidizing agent in the second brine solution to form an aqueous oxidizing agent solution. Then, the step (d) is: adding an aqueous oxidizing agent solution to the aniline compound mixture to react the first aniline compound with the second aniline compound to form an aniline oligomer represented by the structural formula (3).

Wherein x=0 to 7, y=1 to 8, and (x+y)=1 to 8.

In an auxiliary technical means derived from the above-mentioned essential technical means, in the structural formula (2) of the second aniline compound, the functional group R is a hydrogen group, a hydroxyl group, an ester group, an ether group, a sulfonic acid group or a carbonate group. .

In the subsidiary technical means derived from the above-mentioned essential technical means, the step (a) is that a salt compound is dissolved in water to form an aqueous salt solution, and the brine solution is divided into a first salt solution and a second salt solution.

Among the subsidiary technical means derived from the above-mentioned essential technical means, the salt compound is sodium chloride.

In an auxiliary technical means derived from the above-mentioned essential technical means, the oxidizing agent is a mixture of ferric chloride and hydrogen peroxide, ammonium persulfate, potassium persulfate or potassium dichromate.

In an auxiliary technical means derived from the above-mentioned essential technical means, in the step (d), when the aqueous oxidizing agent solution is added to the aniline compound mixed solution, the reaction temperature is controlled to be 0 to 5 °C.

In a subsidiary technical means derived from the above-mentioned essential technical means, the molar concentration ratio of the first aniline compound, the second aniline compound and the oxidizing agent is L:M:N, wherein L=1, M=1, N= 1 to 3.

As described above, since the aniline oligomer provided by the present invention is synthesized by adding a first aniline compound and a second aniline compound to the first salt aqueous solution to form a monoaniline compound mixture, and adding the oxidizing agent aqueous solution to the aniline compound mixture. In the liquid, the first aniline compound is reacted with the second aniline compound to form an aniline oligomer; wherein, since the first aniline compound and the second aniline compound are dissolved in a neutral salt solution, they are not dissolved in the acidic solution. Therefore, the discharge of the acidic waste liquid can be effectively reduced, and the first aniline compound reacts with the second aniline compound in an environment equivalent to the neutral unfavorable polymerization, thereby leading to the formation of the aniline oligomer, and The yield of the aniline oligomer is increased.

The first figure is a flow chart showing the steps of the synthesis method of the aniline oligomer of the present invention.

Please refer to the first figure, which is a flow chart showing the steps of the synthesis method of the aniline oligomer of the present invention. As shown in the figure, a method for synthesizing an aniline oligomer comprises the following steps: First, step S1 is to dissolve a salt compound into water to form an aqueous salt solution, and to divide the brine solution into a first salt solution and a solution. A second brine solution.

Next, in step S2, a first aniline compound represented by the formula (1) and a second aniline compound represented by the formula (2) are added to the first salt aqueous solution to form a mixture of aniline compounds, and the structural formula (1) for , structural formula (2) is Wherein, when the first aniline compound and the second aniline compound are added to the first brine solution, the first aniline compound and the second aniline compound are actually dissolved or suspended in the first salt aqueous solution to form a aniline compound mixed solution.

Next, step S3 is to dissolve an oxidizing agent in the second brine solution to form an aqueous oxidizing agent solution.

Finally, in step S4, an aqueous oxidizing agent solution is added to the aniline compound mixture to react the first aniline compound with the second aniline compound to form an aniline oligomer represented by the structural formula (3), and the structural formula (3) is Wherein x=0 to 7, y=1 to 8, and (x+y)=1 to 8.

As described above, in the present embodiment, the first aniline compound has the formula (1) wherein x=0, that is, the first aniline compound is aniline, and the structural formula is

The second aniline compound has a structural formula (2) of y=1, and the functional group R is H, that is, the second aniline compound is 4,4′-diaminodiphenylamine, and the structural formula is In fact, in fact, 4,4'-diaminodiphenylamine will be used as a source of sulfate, and its structural formula is

As described above, the parameters of the structural formulae (1) and (2) are x=0, y=1, R=H, and the molar concentration ratio of the first aniline compound, the second aniline compound and the oxidant is 1: 1:2, the salt compound of the step (a) is sodium monochloride, the oxidizing agent of the step (b) is ammonium persulfate, and the reaction temperature of the aqueous solution of the oxidizing agent of the step (d) is added to the aniline compound mixture at 0. After stirring to 5 ° C for 1 hour, the first aniline compound and the second aniline compound can react to synthesize an aniline oligomer with a yield of about 86%, and the aniline oligomer is a monoaniline trimer, and the structural formula is

In more detail, in practice, the volumetric molar concentration of the salt compound in the first salt aqueous solution and the second salt aqueous solution in step (a) is 1.28M, and the first aniline compound in step (b) and the second Since the volume fraction of the aniline compound was 8 M, the first aniline compound and the second aniline compound were added to the first salt aqueous solution by continuous stirring for about three minutes to form a aniline compound mixed solution. In the present embodiment, the salt compound is sodium chloride, but is not limited thereto, and may be an alkali metal such as potassium chloride, magnesium chloride or potassium bromide, or a normal salt in which an alkaline earth metal and a halogen are combined.

Step (c) is to dissolve the oxidizing agent in the second brine solution, and the ammonium oxysulfate oxidizing agent is dissolved in the second brine solution to have a molar concentration of 16 M.

Step (d) is to first adjust the temperature of the aniline compound mixture to 0 to 7 ° C by using an ice bath or other cooling means in combination with temperature detection using an ice bath or other cooling means, and then modulating the step (c) The aqueous oxidizing agent solution is gradually added to the aniline compound mixture, and the first aniline compound and the second aniline compound are reacted and oxidized by the oxidizing agent to react and polymerize the aniline oligomer, wherein after the aniline oligomer is formed, it is actually pumped through The aniline oligomer of the solid product was obtained by gas filtration and drying.

Further, since the functional R in the above structural formula (2) is a hydrogen group, the second aniline compound is 4,4'-diaminodiphenylamine, but not To be limited thereto, the functional group R may be a hydroxyl group, an ester group, an ether group, a sulfonic acid group or a carbonate group, and the aniline oligomer produced therefrom is also a derivative having the functional group R.

According to the above, in the case that the first aniline compound is aniline and the second aniline compound is 4,4'-diaminodiphenylamine, the synthesis conditions of the aniline oligomer of the aniline trimer are changed as shown in Table 1 below. Table VII.

Please refer to Table 1 below. Table 1 shows that the salt compound is sodium chloride, the oxidant is ammonium persulfate, the acidic solution of the dissolved oxidant is hydrochloric acid, the reaction temperature is 0 ° C, the first aniline compound, the second aniline compound and the salt The solvent of the compound is hydrochloric acid, the ratio of the molar concentration (M) of the first aniline compound, the second aniline compound and the oxidizing agent is 1:1:1, and the reaction time is 1 hour, and the concentration of the acidic solution is changed to produce different pH. A comparison of the yield changes obtained for the values.

As can be seen from the above Table 1, when the pH of the acidic solution is controlled between 1 and 2, the yield is higher than when the pH is controlled to be 1 or less. Therefore, it is presumed that the strong acid is not suitable for the synthesis of the aniline oligomer.

Please refer to Table 2 below. Table 2 shows that the salt compound is sodium chloride and the oxidant is ammonium persulfate. The acidic solution of the dissolved oxidant is 1M (pH=0.4) hydrochloric acid, the reaction temperature is 0 ° C, the ratio of the volume concentration of the first aniline compound, the second aniline compound and the oxidant to the molar concentration (M) is 1:1:1, and the reaction time is 1 hour. A change table of the yield changes obtained by changing the solvent of the first aniline compound, the second aniline compound and the salt compound.

It can be seen from the above Table 2 that when the solvent of the first aniline compound, the second aniline compound and the salt compound is changed from the hydrochloric acid (HCl) used in the prior art to other weaker acids, the yield is gradually increased, even using water ( When H ₂ O) is used as a solvent, the yield can be effectively increased to 65.82%. Therefore, it is presumed that the synthesis of the aniline oligomer is suitable under the condition that the weak acid is near neutral.

Please refer to Table 3 below. Table 3 shows that the salt compound is sodium chloride, the oxidant is ammonium persulfate, the acidic solution of the dissolved oxidant is 1M (pH=0.4) hydrochloric acid, the first aniline compound, the second aniline compound and the oxidant. The molar concentration (M) of the molar concentration is 1:1:1, and the solvent of the first aniline compound, the second aniline compound and the salt compound is hydrochloric acid, and the reaction temperature is changed to 1 hour, and the reaction temperature (° C.) is changed. Obtained production Rate change table.

It can be seen from Table 3 above that the synthesis yield of aniline oligomers can be effectively improved in a low temperature environment, especially between -5 ° C and 0 ° C, but even if the temperature is slightly increased to 5 ° C, A certain yield can be maintained.

Please refer to Table 4 below. Table 4 shows that the salt compound is sodium chloride, the oxidant is ammonium persulfate, the acidic solution of the dissolved oxidant is 1M (pH=0.4) hydrochloric acid, the reaction temperature is 0 ° C, the first aniline compound, The ratio of the molar concentration (M) of the second aniline compound to the oxidizing agent is 1:1:1, and the yield of the first aniline compound, the second aniline compound and the salt compound is hydrochloric acid, and the reaction time is changed. Rate change table.

As can be seen from Table 4 above, the elongation of the reaction time can increase the synthetic yield of the aniline oligomer, but the range of increase can be limited.

Please refer to Table 5 below. Table 5 shows that the salt compound is sodium chloride, the acidic solution of the dissolved oxidant is 1M (pH=0.4) hydrochloric acid, the reaction temperature is 0 ° C, the first aniline compound, the second aniline compound and the oxidant The volume molar concentration (M) ratio is 1:1:1, and the solvent of the first aniline compound, the second aniline compound and the salt compound is hydrochloric acid, and the reaction time is 1 hour, and the oxidant species is changed. Rate change table.

As can be seen from Table 5 above, ammonium persulfate, potassium persulfate, potassium dichromate, and a mixture of ferric chloride and hydrogen peroxide can all yield a yield of 40% or more.

Please refer to Table 6 below. Table 6 shows that the salt compound is sodium chloride, the oxidant type is ammonium persulfate, the acidic solution of the dissolved oxidant is 1M (pH=0.4) hydrochloric acid, the reaction temperature is 0 ° C, the first aniline compound The yield of the second aniline compound and the salt compound is hydrochloric acid, and the reaction yield is 1 hour, and the ratio of the molar concentration (M) of the first aniline compound, the second aniline compound and the oxidant is changed. Change comparison table.

As can be seen from the above Table 6, when the volumetric molar concentration of the oxidizing agent is twice that of the first aniline compound and the second aniline compound, the yield reaches the highest 73.25%.

It can be seen from the above experimental data that the conditions for influencing the synthesis yield of the aniline oligomer are the first aniline compound, the solvent of the second aniline compound and the salt compound, and the oxidizing agent relative to the first aniline compound and the second aniline. The ratio of the compound, based on which the synthesis conditions are changed to the data as shown in Table 7 below, the yield can be obtained from the prior art 40.21% can be achieved by the surgery to 85.53%

In summary, compared with the prior art, in the strong acid environment, the oxidative coupling method is used to prepare the aniline oligomer, but only about 40% yield can be obtained, and a large amount of acidic waste liquid is generated; The invention is characterized in that the first aniline compound and the second aniline compound are dissolved by using the first salt aqueous solution, and the oxidizing agent aqueous solution obtained by dissolving the salt compound in the second salt aqueous solution is added to the aniline compound mixture to make the first aniline compound and the second aniline compound. An aniline oligomer with a yield of up to 86% can be produced, and the discharge of acidic waste liquid can be effectively reduced, and the reaction can be completed in a short time.

The above is only a preferred embodiment of the invention and is not intended to limit the invention. Any person skilled in the art will disclose the invention without departing from the technical means of the invention. Any changes in the technical means and technical contents of the present invention that do not depart from the technical means of the present invention are still within the scope of the present invention.

Claims (6)

A method for synthesizing an aniline oligomer comprises the steps of: (a) preparing a first salt aqueous solution and a second salt aqueous solution; (b) forming a first aniline compound represented by structural formula (1) and a structure a second aniline compound represented by the formula (2) is added to the first salt aqueous solution to form a mixture of aniline compounds. And the functional group R is a hydrogen group, a hydroxyl group, an ester group, an ether group, a sulfonic acid group or a carbonate group; (c) an oxidizing agent is dissolved in the second salt aqueous solution to form an aqueous oxidizing agent solution; and (d) An aqueous oxidizing agent is added to the aniline compound mixture to react the first aniline compound with the second aniline compound to form an aniline oligomer represented by the structural formula (3). Wherein x=0 to 7, y=1 to 8, and (x+y)=1 to 8. The method for synthesizing an aniline oligomer according to claim 1, wherein the step (a) dissolves a salt compound in water to form an aqueous salt solution, and divides the brine solution into the first salt solution. And the second saline solution. The method for synthesizing an aniline oligomer according to claim 2, wherein the salt compound is sodium chloride. The method for synthesizing an aniline oligomer according to claim 1, wherein the oxidizing agent is a mixture of ferric chloride and hydrogen peroxide, ammonium persulfate, potassium persulfate or potassium dichromate. The method for synthesizing an aniline oligomer according to claim 1, wherein the step (d) is carried out by adding the oxidizing agent aqueous solution to the aniline compound mixture at a temperature of 0 to 5 °C. The method for synthesizing an aniline oligomer according to claim 1, wherein a ratio of a volume concentration of the first aniline compound, the second aniline compound and the oxidizing agent is L:M:N, wherein L =1, M=1, N=1 to 3.