Separation of the non-volatile noble metals by reversed-phase extraction chromatography.
The procedure involves the use of tri-n-butyl phosphate (TBP) adsorbed by Porasil C and stepwise elution with sulphuric acid and hydrochloric acid. The distribution coefficients for the two systems (TBP and hydrochloric acid and TBP and sulphuric acid) and the elution characteristics were studied. A description is given of a procedure applicable to the analysis of prills obtained from the fire assay of platinum-bearing ores.
Some vicinal dioximes as gravimetric reagents.
A series of 3,3-substituted indane-1,2-dionedioximes has been synthesized and their reactions with transition metals have been investigated. From the results obtained it is suggested that the selectivity of such dioximes, as gravimetric reagents, is not a function of the dioxime grouping but is due to metal-metal bonding in the complex.
Highly enantio- and diastereoselective synthesis of β-methyl-γ-monofluoromethyl-substituted alcohols.
Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)(2)AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity.