Catalytic Synthesis of Levulinic Acid by Phosphotungstic Acid

Levulinic acid, also known as fructose, is the basic raw material for the synthesis of various light chemical products, and has high activity.
 
levulinic acid preparation image
 
High value-added products can be produced by chemical reactions such as esterification, halogenation, hydrogenation, oxidative dehydrogenation and condensation. They are widely used in organic synthesis, industry, agriculture and pharmaceutical industry.
 
Although levulinic acid is good, the preparation method is relatively troublesome. There are many problems in the preparation of traditional acid process, such as corrosion of equipment, serious pollution, complex treatment process and difficult separation of products. To solve these problems, scientists are trying to find the appropriate solid acid catalyst to replace the traditional acid catalyst. However, a variety of solid acid catalysts have been tried with little success until the appearance of phosphotungstic acid.
 
Phosphotungstic acid is a kind of heteropoly acid. Because of its excellent catalytic properties and environmental friendliness, it has attracted more and more attention of researchers. It is a new environmentally friendly green catalyst, phosphorus salts include phosphotungstic acid, silver, cesium phosphotungstic, zinc tungstate and copper tungstate. They are generally Keggin structures.
 
Some scholars used silver tungstate to catalyze the conversion of levulinic acid to glucose, in the process, a certain amount of tungstate catalyst was added into glucose solution and placed in a high pressure reactor at 550 °C. The rotational speed was 400r/min, and the reaction temperature was 180 °C for 2h, after the reaction is finished, remove the reactor and cool down to room temperature. The reaction liquid is filtered by 0.22 m microporous filter membrane to form levulinic acid.
 
The experimental results show that the synthesis of levulinic acid with phosphotungstic acid catalyst is stronger than other solid catalysts, and it is also non-toxic and environmentally friendly, at the same time, after using the silver can be washed, recycled, reuse, green chemistry catalyst is significance to promote.
 

 

 

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