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首页> 外文期刊>Environmental Science & Technology >Alkaline Hydrolysis/Polymerization of 2,4,6-Trinitrotoluene: Characterization of Products by 13{sup left}C and 15{sup left}N NMR
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Alkaline Hydrolysis/Polymerization of 2,4,6-Trinitrotoluene: Characterization of Products by 13{sup left}C and 15{sup left}N NMR

机译：2,4,6-三硝基甲苯的碱解/聚合反应：通过13 {C}和15 {N} NMR表征产物

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摘要

Alkaline hydrolysis has been investigated as a nonbiological procedure for the destruction of 2,4,6-trinitrotoluene (TNT) in explosives contaminated soils and munitions scrap. Nucleophilic substitutions of the nitro and methyl groups of TNT by hydroxide ion are the initial steps in the alkaline degradation of TNT. Potential applications of the technique include both in situ surface liming and ex situ alkaline treatment of contaminated soils. A number of laboratory studies have reported the formation of an uncharacterized polymeric material upon prolonged treatment of TNT in base. As part of an overall assessment of alkaline hydrolysis as a remediation technique, and to gain a better understanding of the chemical reactions underlying the hydrolysis/polymerization process, the soluble and precipitate fractions of polymeric material produced from the calcium hydroxide hydrolysis of unlabeled and 15{sup left}N-labeled TNT were analyzed by elemental analysis and 13{sup left}C and 15{sup left}N nuclear magnetic resonance spectroscopy. Spectra indicated that reactions leading to polymerization included nucleophilic displacement of nitro groups by hydroxide ion, formation of ketone, carboxyl, alcohol, ether, and other aliphatic carbons, conversion of methyl groups to diphenyl methylene carbons, and recondensation of aromatic amines and reduced forms of nitrite, including ammonia and possibly hydroxylamine, into the polymer. Compared to the distribution of carbons in TNT as 14% sp{sup}3- and 86% sp{sup}2-hybridized, the precipitate fraction from hydrolysis of unlabeled TNT contained 33% sp{sup}3- and 67% sp{sup}2-hybridized carbons. The concentration of nitrogen in the precipitate was 64% of that in TNT. The 15{sup left}N NMR spectra showed that, in addition to residual nitro groups, forms of nitrogen present in the filtrate and precipitate fractions include aminohydroquinone, primary amide, indole, imine, and azoxy, among others. Unreacted nitrite was recovered in the filtrate fraction. The toxicities and susceptibilities to microbial or chemical degradation of the polymeric materials remain unknown.
机译：碱性水解已作为一种非生物方法进行了研究，用于销毁爆炸物污染的土壤和弹药废料中的2,4,6-三硝基甲苯（TNT）。 TNT的硝基和甲基被氢氧根离子的亲核取代是TNT碱性降解的起始步骤。该技术的潜在应用包括污染土壤的原位表面成灰和异位碱处理。许多实验室研究报告说，在碱中长时间处理TNT会形成未表征的聚合材料。作为对作为补救技术的碱性水解方法进行总体评估的一部分，并且为了更好地理解水解/聚合过程的化学反应，由未标记和15 {通过元素分析，13 C和15 N核磁共振波谱分析了N标记的TNT。 Spectra指出导致聚合的反应包括氢氧根离子对硝基的亲核取代，酮，羧基，醇，醚和其他脂肪族碳的形成，甲基向二苯基亚甲基碳的转化以及芳族胺的再缩合和还原形式的亚硝酸盐（包括氨和可能的羟胺）进入聚合物。与14％sp {sup} 3-和86％sp {sup} 2-杂交时TNT中碳的分布相比，未标记TNT水解产生的沉淀级分包含33％sp {sup} 3-和67％sp { sup} 2-杂化碳。沉淀物中的氮浓度为TNT中的64％。 15 N NMR光谱表明，除残留的硝基外，滤液和沉淀部分中存在的氮形式还包括氨基氢醌，伯酰胺，吲哚，亚胺和，氧基等。在滤液级分中回收未反应的亚硝酸盐。聚合材料对微生物或化学降解的毒性和敏感性仍然未知。

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