The crystal structure of diazomethyl beta-D-galactopyranosyl ketone

The title compound (C8H12N2O6) crystallizes in the orthorhombic space group P2(1)2(1)2(1) (Z = 4), with a = 4.871(1), b = 11.136(2), c = 18.301(2) A. The structure was solved by the multi-solution technique and refined by full-matrix least-squares to a final R-index of 0.042. The compound adopts the 4C1(D) conformation. Bond lengths in the diazoacetyl group are consistent with the presence of a zwitterion.     

Compositional analysis of polysaccharides via solvolysis with liquid hydrogen fluoride

A simple procedure is described for solvolysis of the glycosidic linkages of polysaccharides and related compounds in and by liquid hydrogen fluoride (HF), which does so without destruction of acid-sensitive sugars or formation of reversion products from the released monosaccharides. Following solvolysis, water is added to effect hydrolysis of the resulting glycosyl fluorides. Liberated reducing sugars are determined qualitatively and quantitatively, without derivatization, by high-performance liquid chromatography.     

A mechanistic study of oxygen transfer in aqueous systems

Oxygen transfer coefficients were evaluated for a 14-liter stirred tank fermentor equipped with an oxygen probe, employing elemental copper adsorbed on a weakly basic anion-exchange resin as a solid phase oxygen acceptor. The use of a solid phase oxygen acceptor allowed evaluation of mass transfer resistances associated with the solid phase, and the effect of an oxygen adsorbing solid phase on the overall oxygen transport system, portions of the oxygen transfer process that are neglected by the conventional sulfite oxidation method commonly employed. It was concluded from the data obtained that a transport pathway involving transfer of oxygen to particles present near the air-water interface was a significant oxygen transport pathway for the system studied. Oxygen probe measurements performed on the bulk liquid did not recognize this pathway, suggesting that data taken on biological systems by use of techniques involving oxygen concentration measurements in the bulk liquid may not give the true oxygen absorbing capacity of a system.