2-Chloronicotinic acid

Appearance and shape:
Off-white to brown powder
density:
1.47
Melting point:
176-178℃
Boiling point:
316.8 °C at 760 mmHg
Flash point:
316.8 °C at 760 mmHg
Storage conditions:
Store in a tightly closed container. Store in a cool, dry, well-ventilated area, away from incompatible materials.
PSA:
50.19000
LOGP:
1.43320
Security Information
Hazard category:
IRRITANT
Customs code:
29333999
Dangerous goods transport code:
25kgs
WGK Germany:
3
Hazard category code:
R36/37/38
safety instructions:
S24/25;S26;S37/39
Dangerous goods signs:
Xi
Production methods and uses
production method
There are two preparation methods.
(1) Using 3-methylpyridine as raw material, firstly react with hydrogen peroxide to generate N-oxy-3-methylpyridine, and then in the presence of acid binding agent diisopropylamine, add trichlorooxygen in the solvent. Phosphorus is used as a chlorinating agent for cyclic chlorination to obtain a mixture of 2-chloro-5-methylpyridine and 2-chloro-3-methylpyridine. Using a separation technology combining crystallization and rectification, 2-chloro -5-methylpyridine and 2-chloro-3-methylpyridine. 2-Chloro-3-methylpyridine is chlorinated on the side chain to obtain 2-chloro-3-trichloromethylpyridine, and further hydrolysis can obtain 2-chloro-3-pyridinecarbonyl chloride or 2-chloro-3-pyridinecarboxylic acid (2-Chloronicotinic acid).
(2) Chlorine gas is introduced into the mixture of phosphorus oxychloride and phosphorus trichloride, and the temperature is controlled at about 60°C until the remaining chlorine gas escapes, cooling and adding niacin N-oxide in batches, heating and mixing Liquid in. The reaction was carried out at 100～105℃ for 1～1.5h. After the reaction mixture was transparent, the reaction was stirred for another 30min, and the phosphorus oxychloride was removed under reduced pressure. The resulting residue was cooled to room temperature and water was added to obtain the finished product.
use
1. 2-Chloro-3-pyridinecarboxylic acid is an intermediate of the herbicides nicosulfuron and diflufenican.
2. Used as pharmaceutical intermediates, used in the manufacture of nicotinamic acid, flufenamic acid, etc.; pesticide intermediates, used in the manufacture of nicosulfuron, diflufenican, etc.