Dichloroethane

Abstract: On the Depolymerization of Poly-(R)-3-hydroxy-butanoate (PHB) From cell-free PHB or from dried cells of Alcaligenes eutrophus H 16, which had been grown in an aqueous fructose solution, enantiomerically pure methyl, ethyl, butyl or β-methoxyethyl (R)-3-hydroxy-butanoates are obtained in yields ranging from 75–90% (0.1 to 70 g scale). The depolymerization is achieved by heating the PHB-containing materials to temperatures of 80–160° in the corresponding alcohol with or without the cosolvent dichloroethane in the presence of either sulfuric acid or tetraethoxytitanium catalyst. Since (S)-3-hydroxy-butanoates are also readily obtained (by yeast reduction of aceto-acetates), starting materials derived from 3-hydroxy-butyric acid now belong to the especially useful group of synthetic building blocks which are available in both enantiomeric forms.

Abstract: TpRuPPh3(CH3CN)2PF6 (3 mol %) was very active in catalytic benzannulation of 1-phenyl-2-ethynylbenzenes in dichloroethane (60 °C, 36 h) to afford phenanthrene in 95% yield This method is applicable to the synthesis of various polycyclic aromatic hydrocarbons via two- and four-fold benzannulations, including various substituted coronene derivatives (53−86% yields) using this catalyst at a moderate loading (10 mol %)

Abstract: The solubility of 27 1:1 electrolytes in 1,2-dichloroethane and 25 1:1 electrolytes in 1,1-dichloroethane has been determined. Combination of the solubility values with association constants, and correction for activity coefficients by the extended Debye–Huckel theory, yields standard free energies of solution of the ionic species (M++ X–). From like data in water, free energies of transfer from water to the dichloroethanes have been calculated and have been split into single-ion values through the assumption that ΔGt°(Ph4P+, Ph4As+)=ΔGt°(Ph4B–). It is shown that the free energy of anions (Cl–, Br–, I– and ClO4–) in the dichloroethanes is much higher in value than in water and in dipolar approtic solvents (DMSO, DMF and MeCN). The free energy of most cations (Na+, K+, Rb+, Cs+, Me4N+, Et4N+, Pr4N+ and Bu4N+) is also higher in value in the dichloroethanes than in the dipolar approtic solvents. Both anions and cations are invariably higher in free energy by ∼1 kcal mol–1 in 1,1-dichloroethane than in 1,2-dichloroethane. It is concluded that the (Ph4P+, Ph4As+)=(Ph4B–) assumption yields single-ion free energies of transfer to or from the dichloroethanes that are chemically reasonable.