JPH01316386A - Production of 2,6-(4,4'-diamino-diphenyl)benzo(1,2-d:4,5-d')bisthiazole - Google Patents

Abstract

PURPOSE:To obtain the present substance as a raw material for aromatic heterocyclic polymers in high purity by reacting a diaminobenzenedithiol.dihydrochloride with p-aminobenzoic acid using a mixture containing methanesulfonic acid and phosphorus pentoxide as a reaction medium. CONSTITUTION:2,5-Uiamino-1,4-benzenedithiol.dihydrochloride is reacted with p-aminobenzoic acid using a mixture containing methanesulfonic acid and phosphorus pentoxide as a reaction medium to afford the objective compound expressed by the formula. Furthermore, the mixing ratio of the methanesulfonic acid to the phosphorus pentoxide is preferably (20/1)-(5/1) weight ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior Art) ,z,ts-(tt4'-diamino-diphenyl)
Benzo[/, j--d') bisthiazole (1) is a diamine with good symmetry.

By reacting compound (1) as a monomer with other acid components, it is possible to easily synthesize aromatic heterocyclic polymers that have a high elastic modulus, 7 and excellent heat resistance, and are therefore industrially important. It is expected to be a promising compound.

Conventionally, the above compound (1) is x,j-diamino-/
, produced by reacting co-,5-diamino-/,-benzenedithiol, obtained by dehydrochlorinating G4 benzenedithiol dihydrochloride in polyphosphoric acid as a reaction medium, and p-aminobenzoic acid. method is known. (Publication 6
0-10//23 Publication) This reaction is considered to be the following reaction.

(Problem to be Solved by the Invention) However, this method uses polyphosphoric acid with high viscosity as the reaction medium, and the dehydrochloric acid rate must be kept within a range that allows defoaming. It took a long time to complete the process, which caused manufacturing inefficiency.

- Reacting benzenedithiol dihydrochloride and p-amine benzoic acid; 1. ．． 2.6-(11,lI'-diamino-diphenyl)benzo[:/, 2-d:da, s-d']
A process for producing bisthiazole, characterized in that a mixture containing meta/sulfonic acid and phosphorus pentoxide is used as the reaction medium, with λ0//'',2
//N is more preferably in the range of 20// to 3//.

The present invention provides 2. λ,S-diamino-octag by reacting benzenedithiol dihydrochloride and p-aminobenzoic acid.
A-(p4#-diamino-diphenyl)benzo[l,
, 2-d niger r s d'] A method for producing bisthiazole, characterized in that a mixture containing methanesulfonic acid and phosphorus pentoxide is used as the reaction medium, co, t, -(u, ti' -diamino-diphenyl)
In this case, 3-dimethyl-coimidazolidinone (hereinafter abbreviated as DMI) can be used as a recrystallization solvent.

(Example) Next, the present invention will be further explained with reference to comparative examples and examples.
The present invention is not limited to these comparative examples and examples.

Comparative Example 1 s,s-diamino-/,F-benzenedithiol dihydrochloride 6011 (0,2II !r mol) was mixed with polyphosphoric acid,
It was dissolved in yooooy. 30 hours at room temperature under nitrogen, 30
The mixture was stirred at 0.degree. C. for 1 hour, then stirred for 5 hours under reduced pressure at 0.degree. C., followed by dehydrochloric acid reaction, and the solution became transparent and pale green. Furthermore, para-aminobenzoic acid a I (o, s3t3°C) was added to this under normal pressure nitrogen, and the mixture was reacted at 170°C for 1 hour, at 150°C for 5 hours, and at θO°C for io hours. After the reaction, the product was precipitated with aqueous ammonia, washed with water repeatedly, and dried under vacuum to obtain a yellow-brown crude compound (1). The yield was 7/ti. Furthermore, the crude product obtained in this way under a nitrogen stream is 100! DMI i! ;00m1
The insoluble portion was filtered off, and the filtrate was slowly cooled at room temperature and allowed to stand overnight, resulting in the precipitation of yellow needle-like crystals.

The crystals were collected by filtration, washed with methanol using DMIft, and then dried under vacuum at 0°C. The yield was very low.

Example 1 Co,5-diamino/,II-benzenedithiol dihydrochloride b o I (0-CoH mol) was gradually added to a homogeneous solution consisting of 3.1 Ofi of methanesulfonic acid and 32 of phosphorus pentoxide with hydrochloric acid. This was added while looking at the situation.

The generation of hydrochloric acid ceased 30 minutes after the addition, and at this stage a pale green homogeneous solution was obtained.

The temperature was raised to 70°C, and qpg of p-aminobenzoic acid (0,!;
39 mol) was added and kept at this temperature for 30 minutes. During that time the solution turned orange.

After that, the temperature was increased at a rate of 10°C/hour, and finally i s
The reaction was carried out at o'C for 10 hours. During this time the solution took on a reddish-brown color. After the reaction was completed, a recrystallized purified product was obtained using the procedure shown in Comparative Example. The yield was SO.

(Effects of the Invention) According to the present invention, highly purified 2,4-(II,u'-diamino-diphenyl)benzo(/,,2-d: '1.
! ;-d'] bisthiazole can be obtained efficiently.

As is clear from a comparison between the Comparative Example and the Example, there is no difference in the yield of compound (1), but the rapid heating of the present invention is This shows that the rate of removal of the generated hydrochloric acid is extremely fast.

Claims (1)

[Claims] (1) 2,5-diamino-1,4-benzenedithiol dihydrochloride and p-aminobenzoic acid are reacted, and 2,
6-(4,4'-diamino-diphenyl)benzo[1,
2-d:4,5-d'] A method for producing bisthiazole, characterized in that a mixture containing methanesulfonic acid and phosphorus pentoxide is used as the reaction medium, 2,6
-(4,4'-diamino-diphenyl)benzo[1,2
-d:4,5-d'] Method for producing bisthiazole.