Publisher Summary The properties of a surface are influenced by the surface groups and the knowledge of their existence and of their chemistry are important for many technological processes This chapter examines the surface compounds on carbon—microcrystalline carbon, graphite, and diamond—on silica, on titania, and on alumina and silica–alumina Most important and best known among the surface compounds of carbon are those with oxygen and with sulfur Thus, two kinds of surface oxides are known Basic surface oxides are formed always when a carbon surface is freed from all surface compounds by heating in a vacuum or in an inert atmosphere and comes into contact with oxygen only after cooling to low temperatures Acidic surface oxides are formed when carbon is treated with oxygen a temperatures near its ignition point Unambiguous identification of carboxyl groups has been achieved by two reactions of the acyl chlorides: Friedel–Crafts reaction and Schmidt rearrangement

Chemical Identification of Surface Groups

Publisher Summary This chapter describes the advances with an emphasis on the structures of the alcohol dehydrogenases and the relationship between structure and function Yeast and mammalian alcohol dehydrogenase differ in substrate specificity and rate of catalytic activity The classic yeast enzyme is more specific for acetaldehyde and ethanol, which is consistent with its recognized physiological Significance to participate in alcohol fermentation at the end of the glycolytic pathway Enzyme forms with other functions and properties also occur in yeast The mammalian enzymes have broad substrate specificity and, even with primary alcohols, the maximum activity is not observed with ethanol Alcohols including ethanol, produced in the intestinal tracts mainly by bacterial actions, are found in the portal vein One physiological function of liver alcohol dehydrogenase may be to metabolize these products Structural studies have established that mammalian alcohol dehydrogenases have a distant evolutionary link to both the yeast and bacterial enzymes Ingested alcohol is metabolized to acetaldehyde mainly by the action of liver alcohol dehydrogenase

3 Alcohol Dehydrogenases

https://abulafia.ciencias.uchile.cl/publicaciones/pdf/49-Phytochemistry-27-3349-1988.pdf

Hydroxamic acids (4-hydroxy-1,4-benzoxazin-3-ones), defence chemicals in the Gramineae

Ligand properties of surface silanol groups. I. surface complex formation with Fe3+, Cu2+, Cd2+, and Pb2+

Significant adsorption of Pb(II) on to hydrous γ-Al2O3 from dilute solutions is observed even at pH values far below the zero point of charge. The specific binding of Pb2+ on hydrous γ-Al2O3 in dilute electrolyte is interpreted as surface complex formation. The amphoteric properties of the coordinating surface are characterized in 0.1 M NaC1O4 in terms of a two-protic acid-base system (pHZPC = 8.3). The extent of Pb2+ interaction with the Al2O3 surface was determined both from measurements of residual [Pb2+] with a Pb2+ electrode and from the displacement of alkalimetric titration curves by the presence of Pb(II). The complex forming properties of the surface coordination reaction can be quantified by the equilibria: ≡ AlOH + Pb2+ ⇄ ≡ AlOPb+ + H+; 2 ≡ AlOH +Pb2+ ⇄ (≡ AlO)2Pb + 2H+. Hydrolysis need not be invoked to describe the interaction.

Interaction of Pb2+ with hydrous γ-Al2O3☆

/pdf/precursors-of-benzoxazolinone-in-rye-plants-ii-precursor-i-2aa3p74o7z.pdf

Precursors of Benzoxazolinone in Rye Plants. II. Precursor I, the Glucoside.

The metal ion sorption on silica gel was investigated. The silica gel acts in this respect as an ion exchanger of the weakly acid type and in the case of a monovalent cation the exchange reaction can be written as Si - OH + Me/sup +/ (?) Si - OMe + H/sup +/. For this equilibrium the law of mass action seems to be valid. Moreover an amount of hydrogen ions equivalent to the amount of metal ions sorbed is set free at the sorption on silica gel that is saturated with hydrogen ions. The amount of metal ion sorbed depends strongly on the pH of the solution. At the sorption of strongly hydrolyzed (presumably high molecular) ions the equilibrium is reached slowly, whereas the sorption of nonhydrolyzed (low molecular) ions is quite rapid, the equilibrium usually being reached within five minutes. (auth)

/pdf/the-ion-exchange-properties-of-silica-gel-i-the-sorption-of-22bdxcau28.pdf

THE ION EXCHANGE PROPERTIES OF SILICA GEL. I. THE SORPTION OF Na$sup +$, Ca$sup 2+$, Ba$sup 2+$, UO$sub 2$$sup 2+$, Gd$sup 3+$, Zr(IV) + Nb, U(IV) AND Pu(IV)

/pdf/the-extraction-of-uranium-vi-with-dbp-in-the-presence-of-tbp-1j2y29agst.pdf

The Extraction of Uranium(VI) with DBP in the Presence of TBP. The "Synergic" Effect: Substitution or Addition?.

/pdf/crystalline-leghemoglobin-1-purification-procedure-520c4zufly.pdf

Crystalline Leghemoglobin. 1. Purification Procedure.

A procedure, based on selective sorption on silica gel, was worked out for the separation of plutonium and fission products from uranium which was irradiated with thermal neutrons. (auth) highest distribution ratio. (auth)

/pdf/the-ion-exchange-properties-of-silica-gel-ii-separatioin-of-2uxgz61mny.pdf

Norman E. Levitin

Papers

Precursors of Benzoxazolinone in Rye Plants. II. Precursor I, the Glucoside.

THE ION EXCHANGE PROPERTIES OF SILICA GEL. I. THE SORPTION OF Na$sup +$, Ca$sup 2+$, Ba$sup 2+$, UO$sub 2$$sup 2+$, Gd$sup 3+$, Zr(IV) + Nb, U(IV) AND Pu(IV)

The Extraction of Uranium(VI) with DBP in the Presence of TBP. The "Synergic" Effect: Substitution or Addition?.

Crystalline Leghemoglobin. 1. Purification Procedure.

The ion exchange properties of silica gel. ii. separatioin of plutonium and fission products from irradiated uranium