3*66 JIKUROROPIKORINSANNOSEIZOHO

摘要

p1469610 3,6-Dichloropicolinic acid DOW CHEMICAL CO 23 Dec 1975 [27 Dec 1974 (2)] 52742/75 Heading C2C 3,6-Dichloropicolinic acid is prepared by (1) reacting 3,5,6 - trichloro - 4 - hydrazinopicolinic acid with an alkali metal hydroxide in a liquid reaction medium comprising water and/or C 1-4 alkanol and (2) acidifying the reaction mixture with a mineral acid. Preferably step (1) is carried out at reflux temperature, e.g. 60- 120‹ C., using an excess of the alkali metal hydroxide such as NaOH in water/ethanol. Step (2) is preferably effected with HCl. 3,5,6 - Trichloro - 4 - hydrazinopicolinic acid is obtained (a) from tetrachloropicolinic acid and hydrazine in an aqueous alkaline medium or (b) by acidic hydrolysis of 3,5,6-trichloro-4-hydrazinopicolinonitrile. Pesticidal and plant growth regulant compositions contain 3,6 - dichloropicolinic acid obtained as above./p[GB1469610A]