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Synthesis of aromatic polynitro compounds

Christofi, Joseph Michael Barry; (1994) Synthesis of aromatic polynitro compounds. Doctoral thesis (Ph.D), UCL (University College London). Green open access

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Abstract

This thesis consists of two main areas of study: the first being the mixed acid nitration of compounds in the series [diagram] where X = NH, S, SO, and SO2, and the second area of study being the mechanism of rearrangement of N-nitrocarbazole. For each compound in the above series, the aim was to synthesise polynitro derivatives in a pure state, with high yields for use as energy rich constituents of pyrotechnic compositions. The tetranitro compounds hold the most interest for this particular application. The first compound studied was carbazole (X = NH). 1-Nitro-, 3-nitro-, 1,6- dinitro-, and 3,6-dinitrocarbazole were synthesised by literature methods. The synthesis of 1,3,6,8-tetranitrocarbazole, first achieved over forty years ago, was improved by changing it from a one step to a two step reaction. Nitration of dibenzothiophene (X = S) was hindered by the ease of oxidation of the sulphur atom. The 2-nitro-, 3-nitro-, 2,8-dinitro-, and 3,7-dinitrodibenzo- thiophenes were synthesised by literature methods. The 2,4,8-trinitro- and 2,4,6,8- tetranitrodibenzothiophenes were identified as minor constituents of product mixtures, after separation by preparative HPLC. Dibenzothiophene-5-oxide (X = SO) also proved difficult to nitrate further than the 3,7-dinitro- compound due to the ease of oxidation of the sulphoxide group. The 3-nitro- and 3,7-dinitro- compounds were synthesised by literature methods. The 2.8-dinitrodibenzothiophene-5-oxide was also synthesised. In dibenzothiophene-5,5-dioxide (X = SO2) there were no problems of further oxidation of the sulphone group during nitration. The 3-nitro, 2-nitro, and 3,7-dinitro- compounds were synthesised by literature methods. The 2,7-dinitro-, 2,8-dinitro-, 1,3,7-trinitro-, 1,3,8-trinitro-, 2,3,7-trinitro-, 2,3,8-trinitro-, 1,3,7,8-tetranitro-, and 2.3.7.8-tetranitro- compounds were also synthesised. The mechanism of the acid catalysed rearrangement of N-nitrocarbazole was studied using both 15N and 1H NMR spectroscopy. The rearrangement proved to be a difficult system to study. Small chemically induced dynamic nuclear polarisation (CIDNP) effects were observed in both the acid catalysed and the thermal rearrangements of N-nitrocarbazole.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Synthesis of aromatic polynitro compounds
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Thesis digitised by ProQuest.
Keywords: Pure sciences; Aromatic polynitro compounds
URI: https://discovery.ucl.ac.uk/id/eprint/10104178
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