Continuous TNT process studies : III. Thin-layer chromatographic analysis of oxidation products from nitration
✍ Scribed by C.D. Chandler; J.A. Kohlbeck; W.T. Bolleter
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- English
- Weight
- 538 KB
- Volume
- 64
- Category
- Article
- ISSN
- 1873-3778
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✦ Synopsis
Thin-layer chromatographic separations are shown of all major oxidation products from various steps OF the continuous TNT nitration process and of nitration compounds resulting from impurities'in the toluene used for nitration. This technique has been, used to correlate the formation of the various oxidation products with plant operating conditions and thereby exercise control on the nitration process to minimize oxidation.
INTRQDUCTI&
Two earlier, papers in this series dealt with the thin-layer (TLC)1 and gas chromatographic (GC)2 analysis of samples from the continuous TNT process. The first paper describes the nitration system but was devoted principally to the purification process. The second paper describes a method for determining the amount of the various nitrotoluenes in the organic phase with the aid of response factors and normalization techniques. This third paper deals only with the TLC investigations of oxidation products in nitration.
Although several analytical techniques have been reported for quantitative analysis of TNT, only a few have been concerned with oxidation products, since the majority of the products are present in minor quantities. GEI-IRING~ used NMR to analyze the red oil exudate which appears on the surface of crude TNT after it has stood for several d.ays. This material represents a highly concentrated source of impurities. GEHRING ascribes the color of this exudate to the red z,+dinitrobenzoic acid (z,+DNBA). Other compounds detected by NMR were z,4,6-trinitrobenzoic acid (TNBA), z,4,6-trinitrobenzaldehyde (TNBAl), 3,+dinitrobenzoic acid (3,+DNBA), m-dinitrobenzene (DNB), and a-nitrato-2,4,64rinitrotoluene (a-nitrato-TNT). 'YA~UDA~ reports a TLC separation where oxidation products such as trinitrofl benzene (TNB) and a-nitrato-TNT were observed in,TNT, Several other papers report results. from an intensive investigation of oxidation products resulting ,from the nitration of several aromatic compounds as analyzed by TLC methods (op. cit. ref.
In the first paper by the author+, some oxidation products inherent to the