Selenium is widely used in the fields of electronics, glass, metallurgy, chemical industry, medical care and agriculture, although its yield is low and dispersed in the earth's crust and most of it is recovered as a by-product of copper processing. Selenium and its compounds are often used as catalysts, vulcanizing agents and antioxidants. Selenium as a catalyst has the advantages of mild reaction conditions, low cost, small environmental pollution, convenient post-treatment, etc.
Compared with traditional transition metal catalysts, organic selenium catalysts are ecologically friendly. In addition, organic selenium catalysts also have a series of other advantages, such as low dosage, simple catalyst system, and reusable, clean reaction. These advantages make it possible for organic selenium catalysts to be used in large-scale industrial production in the future.
Deoxime reaction plays an important role in the preparation of drug intermediates. At present, most of the reported deoxime methods use the equivalent heavy metal load as the catalyst, which has the problems of high cost, complicated process and heavy metal pollution. Organic selenium catalysts have unique catalytic performance in oxidation reaction. Because organic selenium catalysis does not use metal elements, the products will not have metal residues, which is suitable for the field of drug synthesis with strict requirements on metal residues. Organic selenium catalysts have been widely used in the oxidation reaction.
The most common inorganic selenium catalysts are elemental selenium and selenium dioxide. The application of elemental selenium as a catalyst is to prepare elemental sulfur by sulfite reaction. Selenium as a catalyst has the advantages of stable structure and performance, which can be recycled and used repeatedly, simple process and equipment, low production cost, no environmental pollution and so on. In addition, selenium can also effectively activate CO to synthesize carbonyl compounds, and plays a phase transfer catalytic role in the reaction process, which is convenient for separation and recovery. Selenium dioxide is one of the most important selenium compounds and has been widely used in the fields of pharmacy, chemical industry and metallurgy. Selenium dioxide, as a cheap and readily available oxidant and catalyst, is used in industry to catalyze propyl oxidation, carbonyl ortho-oxidation, etc., and has been widely used in organic synthesis. Zinc selenide catalyst can adjust the energy band gap width by doping other metals to produce hydrogen by photocatalysis. Cobalt-selenium catalysts have good ORR(Oxygen Reduction Reaction) activity in acidic media and have important applications in the field of fuel cells.