Kinetic studies are reported of the reactions of 1,3,5-trinitrobenzene with aniline in dimethyl sulfoxide (DMSO). In the presence of buffers containing 1,4- diazabicyclo(2.2.2)octane, (Dabco), and its acid salt, DabcoH(^+), the anilide σ-adduct is formed. The reaction of ethyl 2,4,6-trinitrophenyI ether with aniline in DMSO containing Dabco occurs in two stages. The first gives σ-adduct intermediate on the substitution pathway, which has been identified spectroscopically. The second yields 2,4,6-trinitrodiphenyIamine, the substitution product. Kinetic studies show that proton transfer is rate-limiting both in the formation of the intermediate and in its subsequent acid-catalysed decomposition. Phenoxide is a considerably better leaving group than ethoxide and the substitution reactions of phenyl 2,4,6- trinitrophenyl ethers and phenyl 2,4-dinitronaphthyI ether with aniline in DMSO occur without the accumulation of intermediates. The kinetics indicate both uncatalysed and base catalysed pathways. Values have been determined for the pK(_a) in DMSO of several ammonium ions derived from amines which have previously been widely used as nucleophiles in nucleophilic aromatic substitution reactions; values are also given for four polynitrodiphenylamines used as indicators. Second order rate constants (K(_s)) are presented for the reaction of substituted phenyl 2,4,6-trinitrophenyl ethers with a series of phenolate ions having pK(_a) values both higher and lower than that of the respective leaving groups in aqueous solution. The rate constants for the reverse reaction (k(_-s)) have also been measured. The Brømsted diagram formed when plotting log k(_s) versus pK(_a) shows a change in slope when ΔpK(_a) = 0 (ΔpK(_a) being the difference in pK(_a) values of the leaving group and nucleophile). This is consistent with a two step process involving a discrete σ-adduct intermediate. From the measured β values effective charges have been determined and the overall effective charge map constructed. Kinetic studies have been made for the reactions of substituted phenyl 2,4,6- trinitrophenyl ethers with substituted phenolate ions in 74% DMSO-water (v/v). Two reactions are observed. The evidence suggests that the more rapid involves formation of a 1,1 σ-adduct between the substrate and the phenolate ions. The slower reaction is attributed to hydroxide attack at the 3-position of the substrate.

Stuttgart, Univ., Diss., 2001.

This research presents a critical evaluation of chitin- and chitosan-based materials as innovative treatment alternatives for water contaminated with insensitive munitions (IMs) compounds. Specifically, chitin, chitosan, amineunctionalized chitin (AFC) were evaluated for adsorptive removal of these compounds. Cellulose and cellulose triacetate were evaluated for adsorptive performance for comparison. Chitosan-graphene oxide (CSGO) composite membranes were evaluated for removal via adsorption and filtration and compared against nanofiltration and reverse osmosis membranes in the current market. Insensitive munitions evaluated include nitrotriazolone (NTO), nitroguanidine (NQ), and 2,4-dinitroanisole (DNAN); 2,4,6-trinitrotoluene (TNT) was also studied as a traditional munition for comparison. AFC is an effective adsorbent for NTO, DNAN, and TNT. Cellulose triacetate was the only commercially available biopolymer adsorbent effective at removing munitions compounds from solution; only DNAN and TNT were removed. CSGO membranes effectively removed NTO, DNAN, and TNT, but removal performance degraded with time. Overall, this research shows that the materials studied are viable options for removing IM and traditional munitions from water.

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