The solvatochromic comparison method. 4. Dilution studies

Abstract

2) are carried out in progressively more dilute mixtures of HBA (hydrogen bond acceptor) solvents in non-HBA cosolvents. VF50 values of Me2S0 (volume fractions of MezSO in the cosolvents at which the hydrogen bonded complex with 1 is approximately half dissociated) are shown to increase in magnitude with increasing polarity of the cosolvent. A linear relationship between log VFbO values for the Me2SO:1:Me2S0 complex and formation constants reported earlier for the 4-fluorophen01:Me~SO hydrogen bonded complex in the same cosolvents is demonstrated. Self-associating alcohol solvents show nontypical dilution behavior. Dissociation of the (ROH), complexes simultaneously with the l:(ROH), complexes causes -AAv( 1-2) values (enhanced bathochromic shifts attributable to hydrogen bonding) to fall off more rapidly on dilution into non-HBA cosolvents. A comparison of dilution behavior provides strong evidence that the (MeOH), self-association equilibrium constant is significantly higher than that for (t-BuOH),.

Binding of Nitrodiphenylamines to Reverse Micelles of AOT inn-Hexane and Carbon Tetrachloride: Solvent and Substituent Effects

“…The same behavior is observed with phenols having large Kb values (37) and with nitroanilines (20). Thus, since these nitrodiphenylamines as well as nitroanilines can form strong hydrogen bonded complexes with proton acceptors in pure solvents (29,38,39) pre-cmc binding is observed and the use of Eq. [6] to calculate Kb is fully justified.…”

Quick estimation of heats of detonation of aromatic energetic compounds from structural parameters

“…The heat of detonation, Q, defined as the negative of the enthalpy change of the detonation reaction, can be determined from the heats of formation of reactants and decomposition products as following [5]:…”

“…Detonation parameters can also be calculated by some empirical methods [4]. Detonation pressure for ideal explosives, as an example, can be evaluated by different methods such as heat of detonation at loading density greater than 1 g/cm 3 [5][6][7] or any loading density [8], approximate detonation temperature [9][10][11][12] and gas phase heat of formation of explosive [13].…”

“…Moreover, it can also be used to determine detonation pressure and velocity of explosives via assumed different decomposition pathways [5][6][7][8]15]. Predicting fairly simple and accurate heats of detonation, by simple empirical methods, are desired to determine the performance of energetic compounds.…”

“…This work assumes that the number of nitrogens, ratios of oxygen to carbon and hydrogen to oxygen as well as the contribution of some functional groups are sufficient for reliable prediction of heats of detonation as compared to the other available empirical methods. The calculated heats of detonation will be applied to 31 CHNO energetic compounds and compared the results with measured data as well as two empirical methods, namely Kamlet and Jacobs (K&J) [5] as well as Keshavarz and Pouretedal (K&P) [8] methods. It will be shown that the new method is much simple in form and easy to use in a practical sense for quick calculations and screening of notional energetic materials without using any experimental data.…”