Issue 32/2013 - Pesticide intermediate trichloropyridol sodium cleaning process passed qualification

The cleaning process of sodium trichloropyridinol, a pesticide intermediate, passed the identification

Recently, a new clean production process for the production of organic phosphorus insecticidal chlorpyrifos, methyl chlorpyrifos and herbicide chloropyridin sodium 3,5,6-trichloro-2 pyridinol (referred to as trichloropyridol sodium), an important intermediate for the production of organophosphate insecticidal chlorpyrifos, methyl chlorpyrifos and herbicide chloropyridin sodium (referred to as trichloropyridol sodium), has passed the scientific and technological achievements appraisal
organized by the China Petroleum and Chemical Industry Federation in Shandong, China.

The traditional production process of sodium trichloropyridol at home and abroad has the characteristics of high energy consumption and high pollution; The new process adopts the innovative pyridine bidirectional synthesis method, which has the outstanding advantages
of low energy consumption, low "three wastes" emissions, high conversion rate, high selectivity, and product purity greater than 99%.

The innovation points of the project are mainly manifested in the following aspects:
First, a new photochlorination reactor was independently developed, and the conversion rate of pyridine was increased from 90% to more than 99%; The reaction products are monochloropyridine and dichloropyridine, of which 2,6-dichloropyridine accounts for more than
60%.

Second, the use of a solvent with catalytic function can make 2,6-dichloropyridine quantitatively converted into sodium 6-chloro-2-pyridol in one step, the reaction conditions are mild, the separation process is simple, and the yield is more than
99%.

Third, sodium hypochlorite was used as an electrophilic substitution reagent for the β-position directional substitution of sodium 6-chloro-2-pyridinol, and the sodium 3,5,6-trichloro-2-pyridinol was directly generated, with a yield of 80%.


The Chinese government attaches great importance to safety, energy conservation and environmental protection issues, and the delisting of highly toxic and high-residue pesticides has brought a broad market space and development opportunities for chlorpyrifos, and it is expected that the production of chlorpyrifos in China will account for about
45% of global production in 2015.
One of the keys to the rapid increase in the production capacity of chlorpyrifos is the development and innovation
of the synthesis process of sodium trichloropyridinol, an important intermediate.
(Ren)