Kinetics and mechanism of the reaction of sodium azide with hypochlorite in aqueous solution

Eric Betterton, Joe Lowry, Robin Ingamells, Brad Venner

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Production of toxic sodium azide (NaN3) surged worldwide over the past two decades to meet the demand for automobile air bag inflator propellant. Industrial activity and the return of millions of inflators to automobile recycling facilities are leading to increasing release of NaN3 to the environment so there is considerable interest in learning more about its environmental fate. Water soluble NaN3 could conceivably be found in drinking water supplies so here we describe the kinetics and mechanism of the reaction of azide with hypochlorite, which is often used in water treatment plants. The reaction stoichiometry is: HOCl+2N3-=3N2+Cl-+OH-, and proceeds by a key intermediate chlorine azide, ClN3, which subsequently decomposes by reaction with a second azide molecule in the rate determining step: ClN3+N3-→3N2+Cl- (k=0.52±0.04M-1s-1, 25°C, μ=0.1M). We estimate that the half-life of azide would be ≈15s at the point of chlorination in a water treatment plant and ≈24 days at some point downstream where only residual chlorine remains. Hypochlorite is not recommended for treatment of concentrated azide waste due to formation of the toxic chlorine azide intermediate under acidic conditions and the slow kinetics under basic conditions.

Original languageEnglish (US)
Pages (from-to)716-722
Number of pages7
JournalJournal of Hazardous Materials
Volume182
Issue number1-3
DOIs
StatePublished - Oct 2010

Fingerprint

Hypochlorous Acid
Sodium Azide
Azides
Chlorine
chlorine
Water treatment plants
aqueous solution
Sodium
sodium
kinetics
Kinetics
automobile
Automobile air bags
Automobiles
environmental fate
Water Purification
Poisons
Chlorination
stoichiometry
Propellants

Keywords

  • Air bag
  • Azide
  • Chlorine azide
  • Hypochlorite
  • Kinetics and mechanism
  • Water treatment

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Pollution
  • Waste Management and Disposal
  • Environmental Chemistry
  • Environmental Engineering

Cite this

Kinetics and mechanism of the reaction of sodium azide with hypochlorite in aqueous solution. / Betterton, Eric; Lowry, Joe; Ingamells, Robin; Venner, Brad.

In: Journal of Hazardous Materials, Vol. 182, No. 1-3, 10.2010, p. 716-722.

Research output: Contribution to journalArticle

Betterton, Eric ; Lowry, Joe ; Ingamells, Robin ; Venner, Brad. / Kinetics and mechanism of the reaction of sodium azide with hypochlorite in aqueous solution. In: Journal of Hazardous Materials. 2010 ; Vol. 182, No. 1-3. pp. 716-722.
@article{9bbeb42293c247acad2eb26404907fcc,
title = "Kinetics and mechanism of the reaction of sodium azide with hypochlorite in aqueous solution",
abstract = "Production of toxic sodium azide (NaN3) surged worldwide over the past two decades to meet the demand for automobile air bag inflator propellant. Industrial activity and the return of millions of inflators to automobile recycling facilities are leading to increasing release of NaN3 to the environment so there is considerable interest in learning more about its environmental fate. Water soluble NaN3 could conceivably be found in drinking water supplies so here we describe the kinetics and mechanism of the reaction of azide with hypochlorite, which is often used in water treatment plants. The reaction stoichiometry is: HOCl+2N3-=3N2+Cl-+OH-, and proceeds by a key intermediate chlorine azide, ClN3, which subsequently decomposes by reaction with a second azide molecule in the rate determining step: ClN3+N3-→3N2+Cl- (k=0.52±0.04M-1s-1, 25°C, μ=0.1M). We estimate that the half-life of azide would be ≈15s at the point of chlorination in a water treatment plant and ≈24 days at some point downstream where only residual chlorine remains. Hypochlorite is not recommended for treatment of concentrated azide waste due to formation of the toxic chlorine azide intermediate under acidic conditions and the slow kinetics under basic conditions.",
keywords = "Air bag, Azide, Chlorine azide, Hypochlorite, Kinetics and mechanism, Water treatment",
author = "Eric Betterton and Joe Lowry and Robin Ingamells and Brad Venner",
year = "2010",
month = "10",
doi = "10.1016/j.jhazmat.2010.06.093",
language = "English (US)",
volume = "182",
pages = "716--722",
journal = "Journal of Hazardous Materials",
issn = "0304-3894",
publisher = "Elsevier",
number = "1-3",

}

TY - JOUR

T1 - Kinetics and mechanism of the reaction of sodium azide with hypochlorite in aqueous solution

AU - Betterton, Eric

AU - Lowry, Joe

AU - Ingamells, Robin

AU - Venner, Brad

PY - 2010/10

Y1 - 2010/10

N2 - Production of toxic sodium azide (NaN3) surged worldwide over the past two decades to meet the demand for automobile air bag inflator propellant. Industrial activity and the return of millions of inflators to automobile recycling facilities are leading to increasing release of NaN3 to the environment so there is considerable interest in learning more about its environmental fate. Water soluble NaN3 could conceivably be found in drinking water supplies so here we describe the kinetics and mechanism of the reaction of azide with hypochlorite, which is often used in water treatment plants. The reaction stoichiometry is: HOCl+2N3-=3N2+Cl-+OH-, and proceeds by a key intermediate chlorine azide, ClN3, which subsequently decomposes by reaction with a second azide molecule in the rate determining step: ClN3+N3-→3N2+Cl- (k=0.52±0.04M-1s-1, 25°C, μ=0.1M). We estimate that the half-life of azide would be ≈15s at the point of chlorination in a water treatment plant and ≈24 days at some point downstream where only residual chlorine remains. Hypochlorite is not recommended for treatment of concentrated azide waste due to formation of the toxic chlorine azide intermediate under acidic conditions and the slow kinetics under basic conditions.

AB - Production of toxic sodium azide (NaN3) surged worldwide over the past two decades to meet the demand for automobile air bag inflator propellant. Industrial activity and the return of millions of inflators to automobile recycling facilities are leading to increasing release of NaN3 to the environment so there is considerable interest in learning more about its environmental fate. Water soluble NaN3 could conceivably be found in drinking water supplies so here we describe the kinetics and mechanism of the reaction of azide with hypochlorite, which is often used in water treatment plants. The reaction stoichiometry is: HOCl+2N3-=3N2+Cl-+OH-, and proceeds by a key intermediate chlorine azide, ClN3, which subsequently decomposes by reaction with a second azide molecule in the rate determining step: ClN3+N3-→3N2+Cl- (k=0.52±0.04M-1s-1, 25°C, μ=0.1M). We estimate that the half-life of azide would be ≈15s at the point of chlorination in a water treatment plant and ≈24 days at some point downstream where only residual chlorine remains. Hypochlorite is not recommended for treatment of concentrated azide waste due to formation of the toxic chlorine azide intermediate under acidic conditions and the slow kinetics under basic conditions.

KW - Air bag

KW - Azide

KW - Chlorine azide

KW - Hypochlorite

KW - Kinetics and mechanism

KW - Water treatment

UR - http://www.scopus.com/inward/record.url?scp=77955564835&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77955564835&partnerID=8YFLogxK

U2 - 10.1016/j.jhazmat.2010.06.093

DO - 10.1016/j.jhazmat.2010.06.093

M3 - Article

C2 - 20667654

AN - SCOPUS:77955564835

VL - 182

SP - 716

EP - 722

JO - Journal of Hazardous Materials

JF - Journal of Hazardous Materials

SN - 0304-3894

IS - 1-3

ER -