CN111440096A

CN111440096A - ODB-2 dye impurity and preparation method thereof

Info

Publication number: CN111440096A
Application number: CN202010406986.8A
Authority: CN
Inventors: 李敏; 郑庚修; 武海潮; 高令峰; 郑广兵; 崔中倩
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2020-05-14
Filing date: 2020-05-14
Publication date: 2020-07-24

Abstract

The invention relates to a new fluorane thermal pressure sensitive dye 2-phenylamino-3-methyl-6-dibutylamino fluorane (ODB-2) impurity and a preparation method thereof, wherein the impurity is named as 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid, which belongs to the field of organic dyes, the impurity has higher content in the synthesis of ODB-2 dye and has obvious influence on the quality of finished products, and the impurity has poorer refining effect in the refining procedure, so that the ODB-2 dye impurity is easy to exceed the standard, therefore, the generation way of the impurity is researched, the impurity is directionally synthesized, and the method has important significance for the quality control of ODB-2; the method for synthesizing ODB-2 impurities has the advantages of short reaction steps, easily obtained raw materials, high yield and high purity.

Description

ODB-2 dye impurity and preparation method thereof

Technical Field

The invention belongs to the field of organic dyes, and particularly relates to a preparation method of fluorane thermal-pressure sensitive dye ODB-2 impurities.

Background

ODB-2 is a thermosensitive dye for thermal and pressure-sensitive recording paper which is most widely applied in the world at present, has a chemical name of 2-phenylamino-3-methyl-6-dibutylamino fluorane, and has a structural formula shown as a formula III. The dye is developed by NCR company in the United states in 1969, the demand is continuously increased in recent years, the annual demand in the world is up to 10000 tons, and the dye has high color forming sensitivity, deep dyeing, high whiteness, single color development, good light resistance, stable structure and low price, so the dye can be widely used for heat and pressure sensitive recording paper such as labels and faxes, high-speed faxing paper and the like, and can also be used as a thermochromic dye temperature indicating material for electric equipment, mechanical equipment, vehicles and heating equipment.

ODB-2 can be obtained by using 2-methyl-4-methoxydiphenylamine (formula II) and 4-N, N-dibutylamino-2-hydroxy-2' -carboxybenzophenone (formula IV) as raw materials, condensing under an acidic condition to generate an intermediate V, and then closing a ring under an alkaline condition.

The synthetic route of ODB-2 is as follows:

。

ODB-2 dye impurity is very important for dye quality research, the inventor accidentally discovers the impurity in production and finds that the impurity is widely existed in the thermal pressure sensitive dye taking 2-methyl-4-methoxydiphenylamine as a raw material, and documents disclosing the impurity are not found in the prior art.

Disclosure of Invention

The invention aims to solve the technical problem of providing an ODB-2 dye impurity aiming at the current situation of the prior art, and the impurity further provides conditions for the research of ODB-2.

The invention provides a method for synthesizing ODB-2 impurities, aiming at the current situation of the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: an ODB-2 dye impurity, designated 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid, characterized by: the structural formula is shown as the following formula I:

。

of the compound of the formula I¹H NMR spectrum parameters were:¹H NMR（300MHz，CD₃OD）7.79（s，1H），7.37-7.32（t，3H），7.15（s，1H），7.12-6.85（d，2H），3.90（s，3H），2.26-2.18（s，3H）。

a method for synthesizing the novel ODB-2 dye impurity is characterized in that: comprises the following steps

Adding a certain amount of 2-methyl-4-methoxydiphenylamine (formula II) into sulfuric acid with a proper concentration, reacting for a period of time at a certain temperature, and carrying out post-treatment to obtain a compound I.

The reaction formula is as follows:

。

in the step, the mass ratio of the 2-methyl-4-methoxydiphenylamine (formula II) to the sulfuric acid is 1: 3-1: 7, preferably 1: 5; the proper concentration of the sulfuric acid is 85-100%, and the optimal concentration is 100%; the reaction temperature is 25-85 ℃, and the optimal temperature is 50 ℃; the reaction time is 0.5-1.5 h, preferably 0.5 h; the post-treatment method is that the reaction solution is cooled to room temperature, slowly dropped into 50 ml of distilled water, cooled and crystallized, and filtered to obtain the compound I.

Compared with the prior art, the invention has the advantages that: the invention discovers an ODB-2 dye impurity accidentally in the production process, the impurity has higher content in the ODB-2 dye synthesis, the impurity has obvious influence on the quality of a finished product, the refining effect of the impurity is poorer in the refining procedure, and the impurity in the ODB-2 is easy to exceed the standard, so that the research on the generation path of the impurity is carried out, the impurity is directionally synthesized, and the invention has important significance on the quality control of the ODB-2 dye; the synthetic method of ODB-2 dye impurities provided by the invention has the advantages of short reaction steps, easily available raw materials, high yield and high purity.

Drawings

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of an ODB-2 dye impurity of the present invention;

FIG. 2 is a mass spectrum of an ODB-2 dye impurity of the present invention;

FIG. 3 is a graph of HP L C as an impurity for ODB-2 dye prepared in example 1 of the present invention.

Detailed Description

Specific examples of the preparation method provided by the present invention are as follows to further describe the technical scheme of the present invention, but the protection scope of the present invention is not limited to these examples. All changes, modifications and equivalents that do not depart from the spirit of the invention are intended to be included within the scope thereof.

The novel ODB-2 dye impurity of the present invention has the structural formula I:

the synthesis of the novel ODB-2 dye impurity in this example is as follows:

example 1:

adding 50 g of 100% concentrated sulfuric acid into a 100ml three-necked bottle at room temperature, starting stirring, adding 10 g of 2-methyl-4-methoxydiphenylamine solid into a small amount of the three-necked bottle for multiple times, slowly heating to 50 ℃, completely dissolving the solid, controlling the reaction process, reacting for 0.5 h, then removing the raw material point, slowly dropping the reaction solution into 500 ml of distilled water, completely dissolving, cooling, and separating out 13.5 g of solid, namely the target product ODB-2 dye impurity, wherein the yield is 98.47%, and the purity is 99.41%. Subjecting the resulting impurities to mass spectrometry, as shown in FIG. 2; high performance liquid chromatography for purity, as shown in figure 3.

Example 2

Taking a 100ml three-necked bottle, adding 30 g of 100% concentrated sulfuric acid into the three-necked bottle under the same environment as that of the example 1, starting stirring, adding 10 g of 2-methyl-4-methoxydiphenylamine solid into a small amount of the three-necked bottle for multiple times, slowly heating to 50 ℃, completely dissolving the solid, controlling the reaction progress, continuously heating to 80 ℃ after reacting for 0.5 h, reacting for 0.5 h again until the content of the raw material is about 20%, dripping the raw material into 500 ml of distilled water to generate white flocculent undissolved substances, and taking the reaction liquid to perform high performance liquid chromatography analysis, wherein the purity is 79.37%.

Example 3

Under the same environment as that of the example 1, 45 g of 100% concentrated sulfuric acid is put into a 100ml three-necked bottle, stirring is started, 10 g of 2-methyl-4-methoxydiphenylamine solid is added into the three-necked bottle for a few times, the temperature is slowly raised to 50 ℃, the solid is completely dissolved, the reaction progress is controlled, after 0.5 h of reaction, the raw material part is remained, the temperature is continuously raised to 80 ℃, the reaction is carried out for 0.5 h again, the raw material point disappears, the raw material point is dropped into 50 ml of distilled water to be completely dissolved, 13.3 g of solid is separated out after cooling, the yield is 97.01%, and the purity is 98.69%.

Example 4

Under the same environment as that of the example 1, 50 g of 98% concentrated sulfuric acid is added into a 100ml three-necked bottle, stirring is started, 10 g of 2-methyl-4-methoxydiphenylamine solid is added into the three-necked bottle for a few times, the temperature is slowly raised to 50 ℃, the solid is completely dissolved, the reaction progress is controlled, after 0.5 h of reaction, the majority of the raw materials are remained, the temperature is continuously raised to 80 ℃, the reaction is carried out for 0.5 h again, about 30% of the raw materials are remained, the raw materials are dropped into 500 ml of distilled water to generate white flocculent insoluble substances, and the reaction liquid is taken for detection, wherein the purity is 81.32.

Claims

1. An ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid, characterized in that the compound has the formula i:

。

2. a synthetic method of ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula I) is characterized in that: adding a certain amount of 2-methyl-4-methoxydiphenylamine (formula II) into sulfuric acid with a proper concentration, reacting for a period of time at a certain temperature, and performing post-treatment to obtain the compound, wherein the reaction formula is as follows:

。

3. the method for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula I) according to claim 2, wherein the mass ratio of 2-methyl-4-methoxydiphenylamine (formula II) to sulfuric acid is 1:3 to 7.

4. The method of claim 2 for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula i), suitable concentration of sulfuric acid is 85% to 100%.

5. The method of claim 2 for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula i), wherein: sulfuric acid serves both as a solvent and as a reactant.

6. The method for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula I) according to claim 2, wherein the reaction temperature is 25-85 ℃.

7. The method for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula I) according to claim 2, wherein the reaction time is 0.5-1.5 h.

8. The method for synthesizing ODB-2 dye impurity 2-methoxy-4-methyl-5-phenylamino-benzenesulfonic acid (formula I) as claimed in claim 2, wherein the post-treatment is that after the reaction is completed, the reaction solution is cooled to room temperature, slowly dropped into 20-50 ml of distilled water, cooled, crystallized and filtered to obtain compound I.