The invention relates to a method for preparing 2, 2apos; process for the preparation of-diaminobiphenyl

Abstract

The invention relates to a preparation method of 2, 2 '-diaminobiphenyl. The preparation method of 2, 2 '-diaminobiphenyl comprises the following steps: weighing reaction raw materials o-chloroaniline and a catalyst NiCl2 (PPh3) 2; the method comprises the following steps: adding a raw material o-chloroaniline and a catalyst NiCl2 (PPh3) 2 into a reaction kettle, adding a solvent tetrahydrofuran, and carrying out a heating reflux reaction; and cooling and recovering the solvent to obtain the product 2, 2 '-diaminobiphenyl. The method has the advantages that the o-chloroaniline is used as a raw material, the 2, 2 '-diaminobiphenyl is produced through coupling under the catalysis of the catalyst NiCl2 (PPh3) 2, the raw material o-chloroaniline is wide in source and low in price, the purity of the 2, 2'-diaminobiphenyl obtained through reaction is high, and industrial production can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a method for preparing 2,2'-diaminobiphenyl. Background Art

[0002] 2,2'-Diaminobiphenyl is an important intermediate of new materials. In the prior art, the preparation process of 2,2'-diaminobiphenyl mainly includes: 1. o-iodoaniline undergoes Ullmann reaction (Ullmann) for coupling under copper catalysis. This method uses the iodide o-iodoaniline, and the raw material is more expensive than the product, so this route has only theoretical value and no practical value; 2. 2,2'-dinitrobiphenyl is reduced to obtain 2,2'-diaminobiphenyl. This route uses the raw material 2,2'-dinitrobiphenyl. Since biphenyl nitration mainly obtains 4,4'-dinitrobiphenyl, 2,2'-dinitrobiphenyl is only a small amount of by-product, so the source is small and the cost is high. Therefore, it is urgent to develop a new synthesis route for 2,2'-diaminobiphenyl, and it is of great research value to use o-chloroaniline, which is widely available and cheap, as a raw material. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing 2,2'-diaminobiphenyl, which can solve the problem of high cost caused by limited raw material sources for preparing 2,2'-diaminobiphenyl in the prior art.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: comprising the following steps: S1, weighing the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2; S2, adding raw material o-chloroaniline and catalyst NiCl2(PPh3)2 into a reactor, adding solvent tetrahydrofuran, heating and reflux reaction, the reaction process is: ; S3, cooling, recovering the solvent, and obtaining the product 2,2'-diaminobiphenyl.

[0005] Furthermore, the mass ratio of the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2 is 1270:3-5.

[0006] Furthermore, the mass ratio of the added volume of the solvent tetrahydrofuran to the raw material o-chloroaniline is 100:127.

[0007] Furthermore, in step S2, the heating reflux time is 12 hours and the heating temperature is 66°C.

[0008] Furthermore, in step S3, the cooling temperature is 25°C.

[0009] The advantages of the present invention are as follows: the present invention uses o-chloroaniline as a raw material, and produces 2,2'-diaminobiphenyl by coupling under the catalysis of a catalyst NiCl2(PPh3)2; the raw material o-chloroaniline is widely available and cheap; the 2,2'-diaminobiphenyl obtained by the reaction has high purity, and industrial production can be realized. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific implementation methods. The following examples can enable technicians in this field to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0011] This specific implementation adopts the following technical solution: comprising the following steps: S1. Weigh the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2. The mass ratio of the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2 is 1270:3-5.

[0012] S2, adding raw material o-chloroaniline and catalyst NiCl2(PPh3)2 into a reactor, and adding solvent tetrahydrofuran, the mass ratio of the added volume of solvent tetrahydrofuran to the raw material o-chloroaniline is 100:127, heating reflux reaction for 12 hours, and the heating temperature is 66°C.

[0013] The reaction process is ; S3, cooling to 25°C, recovering the solvent, and obtaining the product 2,2'-diaminobiphenyl.

[0014] Embodiment 1: 127 g o-chloroaniline, 0.3 g catalyst NiCl2(PPh3)2, add 100 ml solvent tetrahydrofuran, heat to reflux for 12 hours, heating temperature is 66°C, cool to 25°C, recover the solvent, direct gas phase analysis, product purity is 96%, the structural analysis of the obtained product 2,2'-diaminobiphenyl is shown in the following table.

[0015] Elemental analysis C(78.13%), H(6.52%), N(15.10%) Mass spectrometry m / z 185 1 HNMR(CDCl3) δ=3.8(4H,NH), 6.7-6.8(6H), 7.0(2H) Embodiment 2: 127 g o-chloroaniline, 0.5 g catalyst NiCl2(PPh3)2, 100 ml solvent tetrahydrofuran were added, heated to reflux for 12 hours, cooled, the solvent was recovered, and direct gas phase analysis showed that the product purity was 95%.

[0016] Comparative Example 1: 127 g of o-chloroaniline, 0.8 g of catalyst NiCl2(PPh3)2, 100 ml of solvent tetrahydrofuran were added, heated under reflux for 12 hours, cooled, the solvent was recovered, and direct gas phase analysis showed that the product had a purity of 91%.

[0017] Comparative Example 2: 127 g o-chloroaniline, 1 g catalyst copper powder, add 100 ml solvent tetrahydrofuran, heat to reflux for 12 hours, cool, recover the solvent, direct gas phase analysis, the product purity is 21%.

[0018] By comparing Example 1-2 with Comparative Example 1-2, it can be seen that Example 1-2 uses the catalyst NiCl2(PPh3)2 to catalyze the reaction, and the product purity is relatively high, while Comparative Example 2 uses copper powder as a catalyst to catalyze the reaction, and the product purity is significantly reduced. In addition, in Example 1-2, the amount of catalyst used is less, which reduces the production cost. In Comparative Example 1, the amount of catalyst used is excessive, there are many side reactions, and the product purity is reduced.

[0019] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing 2,2'-diaminobiphenyl, characterized in that: The following steps are involved: S1, weighing the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2; S2, adding raw material o-chloroaniline and catalyst NiCl2(PPh3)2 into a reactor, adding solvent tetrahydrofuran, heating and reflux reaction, the reaction process is: ; S3, cooling, recovering the solvent, and obtaining the product 2,2'-diaminobiphenyl.

2. The method for preparing 2,2'-diaminobiphenyl according to claim 1, characterized in that: The mass ratio of the reaction raw material o-chloroaniline and the catalyst NiCl2(PPh3)2 is 1270:3-5.

3. The method for preparing 2,2'-diaminobiphenyl according to claim 1, characterized in that: The mass ratio of the added volume of the solvent tetrahydrofuran to the raw material o-chloroaniline is 100:

127.

4. The method for preparing 2,2'-diaminobiphenyl according to claim 1, characterized in that: In step S2, the heating reflux time is 12 hours and the heating temperature is 66°C.

5. The method for preparing 2,2'-diaminobiphenyl according to claim 1, characterized in that: In step S3, the cooling temperature is 25°C.

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