Nitrapyrin

Nitrapyrin

Names
IUPAC name 2-Chloro-6-(trichloromethyl)pyridine
Other names N-serve, 2,2,2,6-Tetrachloro-2-picoline
Identifiers
CAS Number	1929-82-4
3D model (JSmol)	Interactive image
ChemSpider	15205
ECHA InfoCard	100.016.076
PubChem CID	16004
InChI InChI=1S/C6H3Cl4N/c7-5-3-1-2-4(11-5)6(8,9)10/h1-3H Key: DCUJJWWUNKIJPH-UHFFFAOYSA-N InChI=1/C6H3Cl4N/c7-5-3-1-2-4(11-5)6(8,9)10/h1-3H Key: DCUJJWWUNKIJPH-UHFFFAOYAC
SMILES c1cc(nc(c1)Cl)C(Cl)(Cl)Cl
Properties
Chemical formula	C6H3Cl4N
Molar mass	230.907
Appearance	colorless/white crystalline solid
Odor	Sweet
Melting point	63 °C; 145 °F; 336 K
Solubility in water	insoluble
Vapor pressure	0.003 mmHg (22.8°C)
Hazards
Main hazards	explosive
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)
REL (Recommended)	TWA 10 mg/m3 (total) ST 20 mg/m3 (total) TWA 5 mg/m3 (resp)
IDLH (Immediate danger)	N.D.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Nitrapyrin is an organic compound with the formula ClC₅H₃NCCl₃. It is a widely used nitrification inhibitor in agriculture as well as a soil bactericide and has been in use since 1974. Nitrapyrin was put up for review by the EPA and deemed safe for use in 2005. Since nitrapyrin is an effective nitrification inhibitor to the bacteria nitrosomonas it has been shown to drastically the reduce NO₂ emissions of soil. Nitrapyrin is a white crystalline solid with a sweet odor and is often mixed with anhydrous ammonia for application.

Nitrapyrin is commonly produced by the photochlorination of 2-methylpyridine:

Produced by DOW Chemical, the product marketed under the trade name N-Serve and contains small amounts (less than 5% wt) of the non-active ingredient 4,6-dichloro-2-trichloromethylpyridine.

Nitrapyrin functions as an inhibitor of the urease enzyme in the nitrifying bacteria Nitrosomonas, preventing hydrolytic action on urea. It is applied to the region of soil and inhibits nitrification for 8–10 weeks. Urease Inhibition specifically prevents the following reaction:

(NH₂)₂CO + H₂O → CO₂ + 2NH₃

Without this capability Nitrosomonas cannot produce nitrite thus inhibiting nitrification:

2NH₄⁺ + 3O₂ → 2NO₂⁻ + 2 H₂O + 4H⁺

Nitrapyrin decomposes both in soil and in plants. The compound itself tends not to persist in nature. The primary decomposition is the hydrolysis of the trichloromethyl functional group, resulting primarily in 6-chloro-picolinic acid which is the only detected residue in plant metabolisms.