title: Transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by permanganate.
abstract: The chemical oxidant permanganate (MnO(4)(-)) has been shown to effectively transform hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) at both the laboratory and field scales. We treated RDX with MnO(4)(-) with the objective of quantifying the effects of pH and temperature on destruction kinetics and determining reaction rates. A nitrogen mass balance and the distribution of reaction products were used to provide insight into reaction mechanisms. Kinetic experiments (at pH ∼ 7, 25 °C) verified that RDX-MnO(4)(-) reaction was first-order with respect to MnO(4)(-) and initial RDX concentration (second-order rate: 4.2 × 10(-5) M(-1) s(-1)). Batch experiments showed that choice of quenching agents (MnSO(4), MnCO(3), and H(2)O(2)) influenced sample pH and product distribution. When MnCO(3) was used as a quenching agent, the pH of the RDX-MnO(4)(-) solution was relatively unchanged and N(2)O and NO(3)(-) constituted 94% of the N-containing products after 80% of the RDX was transformed. On the basis of the preponderance of N(2)O produced under neutral pH (molar ratio N(2)O/NO(3) ∼ 5:1), no strong pH effect on RDX-MnO(4)(-) reaction rates, a lower activation energy than the hydrolysis pathway, and previous literature on MnO(4)(-) oxidation of amines, we propose that RDX-MnO(4)(-) reaction involves direct oxidation of the methylene group (hydride abstraction), followed by hydrolysis of the resulting imides, and decarboxylation of the resulting carboxylic acids to form N(2)O, CO(2), and H(2)O.
authors: Department of Civil Engineering, University of Nebraska-Lincoln , Lincoln, Nebraska 68588-0531, United States.
authors: Chanat
authors: C
authors: Chokejaroenrat
authors: Steve D
authors: SD
authors: Comfort
authors: Clifford E
authors: CE
authors: Harris
authors: Daniel D
authors: DD
authors: Snow
authors: David
authors: D
authors: Cassada
authors: Chainarong
authors: C
authors: Sakulthaew
authors: Tunlawit
authors: T
authors: Satapanajaru
mesh_terms: D053834:Explosive Agents / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D014227:Triazines / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D053834:Explosive Agents; D017895:Manganese Compounds; D010087:Oxides; D014227:Triazines; D014874:Water Pollutants, Chemical; C048856:permanganic acid; C009160:cyclonite