Process for producing 2,3,5-trichloropyridine
US4258194A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | Sep 10, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07F9/4075
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A novel process for producing 2,3,5-trichloropyridine is described. In this process, 2,3,4,5-tetrachloropyridine is reacted, in an alkanephosphonic acid dialkyl ester (dialkyl alkane phosphonate) having 1 to 4 carbon atoms in each of the alkyl groups or in a phosphoric acid trialkyl ester (trialkyl phosphate) having 1 to 4 carbon atoms in each of the alkyl groups as the solvent, at 60.degree. to 120.degree. C., in the presence of 1.4 to 2.8 mols, per mol of 2,3,4,5-tetrachloropyridine, of an ammonium salt of an inorganic or organic acid, with 1.2 to 1.6 gram atoms of zinc per mol of 2,3,4,5-tetrachloropyridine, the 2,3,4,5-tetrachloropyridine being selectively dechlorinated in the 4-position. 2,3,5-Trichloropyridine is a valuable intermediate for producing herbicidally effective .alpha.-[4-(3',5'-dichloropyrid-2-yloxy)-phenoxy-]-alkanecarboxylic acids and derivatives thereof. There are also described novel ammonium salts of methanephosphonic acid monomethyl ester, in the presence of which salts the selective dechlorination of 2,3,4,5-tetrachloropyridine in the 4-position is advantageously performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.