Microwave-assisted hydrolysis of nitroglycerin (NG) under mild alkaline conditions: New insight into the degradation pathway

作者：Halasz Annamaria; Thiboutot Sonia; Ampleman Guy; Hawari Jalal^*

来源：Chemosphere, 2010, 79(2): 228-232.

DOI：10.1016/j.chemosphere.2010.01.013

• Nitroglycerin
• Alkaline hydrolysis
• Microwave
• 2-Hydroxypropanedial
• Degradation pathway

Nitroglycerin (NC), a nitrate ester, is widely used in the pharmaceutical industry and as an explosive in dynamite and as propellant. Currently NC is considered as a key environmental contaminant due to the discharge of wastewater tainted with the chemical from the military and pharmaceutical industry. The present study describes hydrolytic degradation of NC (200 mu M) at pH 9 using either conventional or microwave-assisted heating at 50 degrees C. We found that hydrolytic degradation of NC inside the microwave chamber was much higher than its degradation using conventional heating. Products distributions in both heating systems were closely related and included nitrite, nitrate, formic acid, and the novel intermediates 2-hydroxypropanedial (O=CHCH(OH)HC=O) and glycolic acid (CH(2)(OH)COOH). Two other intermediates glycolaldehyde (CH(2)(OH)CHO) and glyoxylic acid (CHOCOOH) were only detected in the microwave treated samples. The molar ratio of nitrite to nitrate in the presence and absence of microwave heating was 2.5 and 2.8, respectively. In both microwave assisted and conventional heating a nitrogen mass balance of 96% and 98% and a carbon mass balance of 58% and 78%, respectively, were obtained. The lower C mass recovery might be attributed to further unknown reactions, e.g., polymerization of the aldehydes CH(2)(OH)CHO. CHOCOOH and O=CHCH(OH)HC=O. A hydrolytic degradation pathway for NC was proposed involving denitration (loss of 2 NO(2)(-)) from the two primary carbons and the loss of one nitrate from the secondary carbon to produce 2-hydroxypropanedial.

• 出版日期2010-3