JP4473148B2 - Method for producing 3,4'-diaminodiphenyl ether - Google Patents

Description

  The present invention relates to a method for producing 3,4'-diaminodiphenyl ether used as a monomer raw material for polymerization of functional polyamide or polyimide, or a modification additive.

  In the production of 3,4'-diaminodiphenyl ether, a method of condensing 3-aminophenol and 4-chloronitrobenzene and then reducing is carried out. In addition, it is known that high purity is required for 3,4'-diaminodiphenyl ether used for special purposes, and various proposals have been made to obtain pure 3,4'-diaminodiphenyl ether. . For example, in order to reduce the proportion of isomers, a method has been proposed in which the content of 2-chloronitrobenzene contained in the raw material 4-chloronitrobenzene is 0.1% by mass or less (see Patent Document 1). Further, in order to prevent the thermal decomposition product during distillation of 3,4'-diaminodiphenyl ether from being mixed into 3,4'-diaminodiphenyl ether, the boiling point range of 240-240 In addition to an inert organic solvent at 350 ° C., a method of performing distillation purification of 3,4′-diaminodiphenyl ether has been proposed (see Patent Document 2).

  In order to suppress thermal decomposition of high-boiling products such as by-products during distillation, the reaction solvent is added within 8 hours under conditions of a tower top temperature of 60 to 150 ° C. and a tower top pressure of 1.3 to 266.6 hectopascals. There has been proposed a method of distilling and distilling 3,4'-diaminodiphenyl ether under conditions of a column top pressure of 66.6 hectopascals or less (see Patent Document 3). On the other hand, 3,4'-diaminodiphenyl ether having a low chlorine concentration is required as a monomer raw material for polymerizing polyamide or polyimide used in the field of special electronic materials. In the above method, it is difficult to obtain 3,4'-diaminodiphenyl ether that satisfies the requirement because the chlorine component is likely to be mixed.

Further, in the conventional method for producing 3,4′-diaminodiphenyl ether, nitrogen-containing organic solvents such as dimethylformamide and N-methylpyrrolidone are widely used as reaction solvents, but these solvents reacted during the condensation reaction. Impurities (such as amidine derivatives) are generated. This impurity is decomposed during the distillation of 3,4'-diaminodiphenyl ether to generate a chlorine component, so that the 3,4'-diaminodiphenyl ether contains a trace amount of chlorine component.
Japanese Patent Laid-Open No. 61-225155 JP-A-61-221159 JP-A-8-27077

  An object of the present invention is to provide a method for producing 3,4'-diaminodiphenyl ether having a low chlorine concentration.

  As a result of intensive studies to achieve the above object, the present inventors condensated 3-aminophenol and 4-chloronitrobenzene, and then reduced to produce 3,4'-diaminodiphenyl ether. At that time, it was found that by using dimethyl sulfoxide without using a nitrogen-containing organic solvent as a reaction solvent, 3,4'-diaminodiphenyl ether having a chlorine concentration of 10 ppm or less can be obtained in good yield, and the present invention has been achieved.

That is, the present invention has the following configuration.
(1) After condensing 3-aminophenol and 4-chloronitrobenzene, the resulting solution after the condensation reaction is further reduced as it is to obtain 3,4'-diaminodiphenyl ether, and the reaction solvent is dimethyl sulfoxide. A process for producing 3,4'-diaminodiphenyl ether, characterized in that
(2) The method for producing 3,4'-diaminodiphenyl ether according to (1), wherein the amount of the dimethyl sulfoxide used is 100 to 500 parts by mass with respect to 100 parts by mass of 4-chloronitrobenzene.

  Since 3,4'-diaminodiphenyl ether obtained by the present invention has a low chlorine concentration, it can be used as a monomer raw material for polymerization of polyamide and polyimide used in the field of special electronic materials.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments.
In the present invention, the solvent used in the condensation reaction of 4-chloronitrobenzene and 3-aminophenol and the subsequent reduction reaction is dimethyl sulfoxide. The amount of dimethyl sulfoxide used is 100 to 500 parts by mass with respect to 100 parts by mass of 4-chloronitrobenzene. If the amount is less than 100 parts by mass, the production of heavy substances increases and the yield is reduced.

  In the present invention, the condensation reaction of 4-chloronitrobenzene and 3-aminophenol is carried out in dimethyl sulfoxide using an alkali metal carbonate that is a condensing agent. The alkali metal carbonate is preferably potassium carbonate or sodium carbonate. The amount of alkali metal carbonate used is preferably 1 to 3 times the number of moles per mole of 4-chloronitrobenzene. The chlorine component can be reduced by using an excessive amount of alkali metal carbonate. The reaction temperature for the condensation reaction is 130 to 160 ° C., and the reaction time is 4 to 12 hours.

  The solution after the condensation reaction obtained above can be directly used for the reduction reaction without isolating the reaction product.

  The reduction reaction method includes (a) a reduction method by blowing hydrogen gas into the condensation reaction product in the presence of a catalyst and (b) a direct reduction method in which hydrazine is added and reacted in the presence of a catalyst. A direct reduction method with hydrazine is preferred.

  As a catalyst used for the direct reduction reaction with hydrazine, it is preferable to use a trivalent iron compound. Examples of the trivalent iron compound include iron (III) oxide powder, iron (III) chloride, and iron (III) hydroxide. Specifically, it is preferable to use iron (III) chloride and activated carbon. In the presence of the reduction catalyst, hydrazine is added to the solution after the condensation reaction to perform direct reduction. The reaction temperature of the direct reduction reaction is 50 to 110 ° C., and the reaction time is 1 to 8 hours. The amount of hydrazine added is preferably 1 to 4 times the number of moles used per mole of 4-chloronitrobenzene.

  Next, water generated by the direct reduction reaction is distilled off, and the reduction catalyst and the inorganic salt are removed by filtration to obtain a dimethyl sulfoxide solution of crude 3,4'-diaminodiphenyl ether. Then, this solution is concentrated under reduced pressure under normal conditions, followed by distillation purification of 3,4'-diaminodiphenyl ether. Since the 3,4'-diaminodiphenyl ether thus obtained has a low chlorine concentration, it can be used as a monomer raw material for polymerization of polyamide and polyimide used in the field of special electronic materials.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited thereto. In the following, “%” of purity is based on mass.
<Example 1>
[I. Synthesis of 3-amino-4′-nitrodiphenyl ether]
157 g of 4-chloronitrobenzene, 109 g of 3-aminophenol, 76 g of potassium carbonate, and 266 g of dimethyl sulfoxide were charged and reacted at 150 ° C. for 8 hours.

[II. Synthesis of 3,4′-diaminodiphenyl ether]
To the obtained reaction solution, 32 g of activated carbon and 8 g of iron (III) chloride were added and heated to 80 ° C. Next, 99 g of hydrazine monohydrate was added dropwise over 3 hours and aged for 2 hours. Next, water was distilled off, and the produced salt (potassium chloride) and activated carbon were separated by filtration to obtain a 3,4′-diaminodiphenyl ether solution.

[III. Concentration / distillation]
The 3,4′-diaminodiphenyl ether solution was concentrated under reduced pressure at 100 ° C. under a reduced pressure of 66.6 hectopascals. Next, the pressure was reduced to 2.6 to 3.9 hectopascals, and 3,4′-diaminodiphenyl ether was distilled at a distillation temperature of 205 to 210 ° C. to obtain 150 g of 3,4′-diaminodiphenyl ether. The yield was 75% based on 4-chloronitrobenzene.

  When the obtained 3,4'-diaminodiphenyl ether was analyzed by gas chromatography, the purity was 99.2%. Further, when 3,4'-diaminodiphenyl ether was subjected to potentiometric titration with silver nitrate, the chlorine ion concentration was 5 ppm.

<Comparative Example 1>
The same operation as in Example 1 was performed except that dimethylformamide was used in place of dimethyl sulfoxide as a reaction solvent.

  When the obtained 3,4'-diaminodiphenyl ether was analyzed by gas chromatography, the purity was 99.2%. Further, when potentiometric titration with silver nitrate was performed on 3,4'-diaminodiphenyl ether, the chlorine ion concentration was 110 ppm.

The 3,4′-diaminodiphenyl ether obtained in the present invention is extremely low in chlorine and can be used as a monomer raw material for polymerization of polyamide and polyimide used in the field of special electronic materials.

Claims (2)

After condensing 3-aminophenol and 4-chloronitrobenzene, the resulting solution after the condensation reaction is further reduced as it is to obtain 3,4'-diaminodiphenyl ether, and the reaction solvent is dimethyl sulfoxide. A process for producing 3,4'-diaminodiphenyl ether, characterized in that   The method for producing 3,4'-diaminodiphenyl ether according to claim 1, wherein the dimethyl sulfoxide is used in an amount of 100 to 500 parts by mass with respect to 100 parts by mass of 4-chloronitrobenzene.