Diffusion coefficient and solubility of isobutene and trans-2-butene in aqueous sulfuric acid solutions

The diffusion coefficient and the physical solubility of isobutene and tran s-2-butene in aqueous sulfuric acid solutions cannot be determined experime ntally due to the occurrence of fast chemical reactions. In the present con tribution these physicochemical parameters are estimated. For the solubilit y an isobutane-isobutene analogy is applied for the range 0-100% H2SO4. A c orrelation technique, initially proposed by Rudakov et al.,(11) was used fo r describing the experimental data at low acid concentrations and for estim ation purposes for more concentrated solutions. Diffusion coefficients for inert gases in electrolyte solutions were measured using a modified diaphra gm cell. It was found for CO2 and N2O in KCl solutions that the diffusion c oefficient is not a function of the ionic strength of the electrolyte solut ion and therefore not a function of the activity coefficient of the diffusi ng component. It appears that the correlation D eta (0.6) = constant holds up to 80 mass % sulfuric acid, as is the case for several other aqueous ele ctrolyte solutions. Diffusion coefficients for butenes in sulfuric acid sol utions (up to 96 mass %) are estimated from CO2 coefficients in these solut ions.