Preparation method of 4, 4'-dinitrobibenzyl

Abstract

The invention discloses a novel preparation method of 4, 4'-dinitrobibenzyl. According to the method, p-nitrotoluene is used as a reactant, oxygen is used as an oxidizing agent, ethanol is used as a solvent, transition metal doped FDU-12 mesoporous molecular sieve supported guanidine salt ionic liquid is used as a catalyst, and 4, 4 '-dinitrobibenzyl is prepared through high-selectivity oxidative dehydrogenation coupling reaction. After the reaction is finished, the catalyst phase and the product phase are easily subjected to heterogeneous separation and can be well recycled. The method has the advantages of simple operation, mild reaction conditions, small catalyst dosage, high reaction efficiency and selectivity, and small discharge of three wastes, and is a novel green and clean preparation method.

Description

technical field [0001] The invention relates to a method for preparing 4,4'-dinitrobibenzyl through the oxygen-selective oxidative dehydrogenation coupling of p-nitrotoluene catalyzed by a mesoporous molecular sieve-loaded guanidinium salt ionic liquid, which belongs to the technical field of fine chemicals. [0002] technical background [0003] 4,4'-Dinitrobibenzyl is an important fine organic synthesis intermediate, which can be used in the production of medicines, pesticides, dyes, polymers, etc. At present, there are mainly three synthetic methods for preparing 4,4’-dinitrobibenzyl at home and abroad, namely reductive coupling method, diphenylethane nitration method and oxidative coupling method. The reductive coupling method mainly uses p-nitrobenzyl halides as raw materials, organic solvents, inorganic solvents or ionic liquids as solvents, and transition metals, metal salts, metal complexes, etc. as catalysts for catalytic reactions (Tetrahedron Lett., 2015, 56 (19),...

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Problems solved by technology

The reductive coupling method mainly uses p-nitrobenzyl halides as raw materials, organic solvents, inorganic solvents or ionic liquids as solvents, and transition metals, metal salts, metal complexes, etc. as catalysts for catalytic reactions (Tetrahedron Lett., 2015, 56 (19), 2480-2487; New J.Chem., 2016, 40(12), 9912-9916; Catal.Sci.Technol., 2015, 5(9), 4336-4340; Chem.Commun., 2014, 50(36), 4674-4676), the product yield of this process is high, but a large amount of halogen-containing by-products will cause environmental pollution and corrode equipment during the reaction process, and the catalyst cannot be recovered well, and the operating cost is high

The diphenylethane nitration method mainly uses diphenylethane as a raw material, and the nitric acid with a specific gravity of 1.42 is used as a nitrating reagent or a mixed acid for nitration reaction (Ind.Eng.Chem.Prod.Res.Dev., 1977,16,309-311), The product yield of this process is high, but the selectivity of the reaction process is low, and a large amount of waste acid will be produced, the post-treatment is troublesome, the operation cost is high, and it is not environmentally friendly.

Oxidative coupling is a very promising method. The oxidation performance of hydrogen peroxide is better than that of oxygen, and it can be removed by heating. It is green and environmentally friendly. The disadvantage is that the industrialization cost is high, and the operation has certain hazards.

Oxygen oxidation method Oxygen is cheap and easy to obtain, low cost, and simple to operate, but the methods reported so far have more or less problems such as low conversion rate, low yield, high energy consumption, a large amount of waste alkali that cannot be recycled and recycled, and environmental pollution, etc. question

Other preparation methods include electrochemical reduction and coupling without adding an oxidant (Bul.Chem.Soc.Jpn., 2003, 76(11), 2155-2165; CN107298645A; CN101362695): the electrochemical reduction method first synthesizes sulfonium Salt, then carry out cathodic reduction reaction, the target product is obtained by the reduction of sulfonium salt, the advantage of this method is that the yield is high, but the reaction operation is troublesome, the cost is high, safety control is difficult to achieve, and it is difficult to realize industrial production; without adding oxidant coupling method, which has low yield, poor selectivity and serious pollution

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