The chemical process accompanying the hydrogenation of fats I. Geometrical isomerization
Summary1. It has been shown for numerous examples that the catalytic hydrogenation of fats is accompanied by the cis-trans isomerization of the radicals of the unsaturated acids.2. A scheme is proposed which explains the mechanism of the isomerization through a process of the hydrogenation-dehydrogenation of the olefinic compounds.
Modern State of the Multiplet Theor of Heterogeneous Catalysis
Publisher Summary This chapter reviews the modern state of the multiplet theory of heterogeneous catalysis. The multiplet theory deals with numerical values of bond lengths and bond energies, as well as with the geometrical form of reacting molecules and the crystal lattices of catalysts. This allows definite results to be obtained for many reactions on an atomic level. This is how the multiplet theory differs from a number of other theories on catalysis. The theory of the structure of matter is based on both electronic theory and quantum mechanics—the basis for the multiplet theory. Bond lengths and energies represent a stable complex of electronic properties essential for catalysis. The multiplet theory proceeds from the premise that catalysis is a chemical phenomenon and that covalent bonds require catalytic activation.
Protective effect of ginsenoside Re on acute gastric mucosal lesion induced by compound 48/80
The protective effect of ginsenoside Re, isolated from ginseng berry, against acute gastric mucosal lesions was examined in rats with a single intraperitoneal injection of compound 48/80 (C48/80). Ginsenoside Re (20 mg/kg or 100 mg/kg) was orally administered 0.5 h prior to C48/80 treatment. Ginsenoside Re dose-dependently prevented gastric mucosal lesion development 3 h after C48/80 treatment. Increases in the activities of myeloperoxidase (MPO; an index of neutrophil infiltration) and xanthine oxidase (XO) and the content of thiobarbituric acid reactive substances (TBARS; an index of lipid peroxidation) and decreases in the contents of hexosamine (a marker of gastric mucus) and adherent mucus, which occurred in gastric mucosal tissues after C48/80 treatment, were significantly attenuated by ginsenoside Re. The elevation of Bax expression and the decrease in Bcl2 expression after C48/80 treatment were also attenuated by ginsenoside Re. Ginsenoside Re significantly attenuated all these changes 3 h after C48/80 treatment. These results indicate that orally administered ginsenoside Re protects against C48/80-induced acute gastric mucosal lesions in rats, possibly through its stimulatory action on gastric mucus synthesis and secretion, its inhibitory action on neutrophil infiltration, and enhanced lipid peroxidation in the gastric mucosal tissue.