Agrochemicals

Pyridine is a six membered heterocyclic compound containing one aza atom, that is, a compound formed by the substitution of one carbon in benzene molecule with nitrogen. It is similar to benzene in that it has the same electronic structure and still has aromaticity. Pyridine and its derivatives are more stable than benzene, and their reactivity is similar to nitrobenzene. Due to the electron absorption of nitrogen atoms in the ring, the electron density at positions 2, 4 and 6 is lower than that at positions 3 and 5. The typical aromatic electrophilic substitution reaction occurs at positions 3 and 5, but the reactivity is lower than that of benzene, so it is generally not easy to nitration, halogenation and sulfonation. In addition, these substitution reactions are carried out in acidic medium. Pyridine forms positively charged ions, which make electrophilic reagents inaccessible. The halogens of 2-or 4-halopyridines are active. Because of the low electron density at positions 2 and 6, nucleophilic substitution reactions can take place at these positions, such as reaction with sodium amino or potassium hydroxide, to give corresponding 2-aminopyridine or 2-hydroxypyridine. Pyridine can also be used as denaturant and dyeing aid in industry, as well as the starting material for synthesis of a series of products, including drugs, disinfectants, dyes, food seasonings, adhesives, explosives and so on. Pyridine is toxic, inhalation, ingestion or skin contact can lead to reduced male fertility, can also cause cancer.

Fipronil is the first benzopyrazole used for pest control. Since its discovery in 1987, it has been widely used in many fields such as agriculture and veterinary medicine, and has become an important insecticide variety. Non prednisolone, trade name regent, is a new type of benzopyrazole insecticide. Compared with traditional insecticides (organophosphorus, pyrethroid and carbamate), it has the advantages of broad spectrum and high efficiency. It has been widely used in many agricultural fields and is a common insecticide for pest control. Fipronil is mainly produced by blocking γ- Aminobutyric acid receptor controlled Cl - channel induces Cl - flow, which causes the nervous system to be extremely excited and leads to the death of insects, so as to achieve the control effect on a variety of economic pests.

Ammonium chloride (chemical formula: NH4Cl) is colorless cubic crystal or white crystal. It tastes salty, cool and slightly bitter. It is easily soluble in water and liquid ammonia and slightly soluble in alcohol, but insoluble in acetone and ether. The aqueous solution is weakly acidic and the acidity increases when heated. Due to the coordination of ammonium ions, the ammonium chloride solution is corrosive to metals, especially copper.

Cyhalofop-butyl is an oxyphenoxypropionic acid type herbicide. It is mainly used in rice seedling field, direct seeding field and transplanting field to control most malignant gramineous weeds such as barnyardgrass, Qianjin and niujin grass, and can effectively control weeds resistant to dichloroquinolinic acid, sulfonylurea and amide herbicides. It has the characteristics of high efficiency, low toxicity and low residue.

It is used to produce hydrogenation, desulfurization and other petroleum refining catalysts, trace element fertilizers, and raw materials for manufacturing ceramic pigments, pigments and other molybdenum compounds.