Thermochemical investigations of associated solutions: calculation of solute--solvent equilibrium constants from solubility measurements.
A simple solution model that has lead to successful predictive equations for the partial molar excess properties of a solute in simple binary solvent mixtures containing only nonspecific interactions is extended to include association between the solute and one of the solvent components. An expression is derived and tested for its ability to describe anthracene solubilities in binary solvent mixtures containing benzene. The best description of the experimental solubilities requires the formation of a 1:1 anthracene-benzene complex, with a molarity-based equilibrium constant of KcAC approximately equal to 0.107 M-1. In comparison, a stoichiometric complexation model which attributes all solubility enhancement to the formation of anthracene-benzene complexes requires a somewhat larger equilibrium constant (KcAC approximately equal to 0.228 M-1) to describe the solubility behavior of anthracene in the benzene-n-heptane system. The results of these calculations illustrate that the determination of solute-solvent equilibrium constants from solubility data depends on the theoretical model used and the manner in which nonspecific interactions are incorporated into the model.
Vapour pressures and excess Gibbs energies of mixtures of benzene with chlorobenzene, n-hexane, and n-heptane at 25°C
Excess Gibbs energies, which were calculated from static vapour pressure measurements, are reported for benzene + chlorobenzene, benzene + n-hexane, and benzene + n-heptane at 25°C. The excess Gibbs energy per unit volume is found to be a symmetrical function of the volume fraction for the benzene + alkane systems.
Human Rights Obligations and Transnational Corporations: The Limits of Direct Corporate Responsibility
To date, multinational corporations have had no direct human rights obligations under international law. Nonetheless, international lawyers can no longer ignore the increasing role of non-state actors in international society. This article suggests analysing existing mechanisms and new proposals for enhancing the accountability of transnational corporations, grouped into those focusing on the responsibility of the home and host states and those centred on the imposition of direct obligations on corporations. This article will specifically draw attention to the limits of some of the suggested normative changes, from a legal-theoretical perspective and in terms of their capacity to address effectively the challenges of the lack of respect for human rights laws.