A combined LEED/RHEED Auger study of oxygen adsorption on the W(112) surface

LEED, RHEED and Auger spectroscopy have been used to study the adsorption of oxygen on to a clean and carbon contaminated (112) face of tungsten. At room temperature all the features reported previously were observed together with a p(1 × 4) surface structure which appeared at an exposure of about 1. 4L just before the formation of the p(1 × 2). Previously a p(1 × 4) structure has been reported only after heating to 2000K. RHEED showed this p(1 × 4) structure clearly; using LEED, the structure was difficult to distinguish. This appears to confirm suspicions that in some situations involving gas adsorption, RHEED has a greater sensitivity than LEED. Possibly most of these situations involve, as does the present p(1 × 4) structure, monolayer islands where the differing coherence widths of the RHEED and LEED beams account for the differing sensitivities. Carbon on the (112) surface also appears to exist as thin islands, either of the previously reported c(6 × 4) structure, or in smaller amounts, on a surface showing (1 × 1) symmetry. Removal of all carbon by heat treatment alone was found to be impossible in a reasonable time and heating in oxygen was necessary. Oxygen adsorption on a carbon contaminated surface did not give rise to any new structures but rather a reduction in the visibility/formation of the clean surface/oxygen structures.     

The kinetics of the decarboxylation of malonic acid in normal alkanols

Rate constants and activation parameters are reported for the decarboxylation of malonic acid in seven normal alkanols (butanol-l to decanol-l inclusive). It is found that the enthalpy of activation of the reaction is a linear function of the number of carbon atoms in the hydrocarbon chain of tthe solvent, expressed by the equation: ΔH^≠ = –600n + 30,000, where n is thenumber of carbon atoms in the chain. Also an equation is developed relatingthe rate constant for the decarboxylation of malonic acid in normal alkanols to n (the number of carbon atoms in the chain): log K = 10.854283 – 0.3212674n + (131.136876n – 6556.5438)/T + log T. With the aid of this equation rate constants may be calulated for the decarboxylationof malonic acid in any alcohol at any temperature which agree with experimental values to within the limit of error of the experiments. A comparison of the data obtained in the present research for the decarboxylation of malonic acid in normal alkanols with previously reported data for the reaction in amines indicates that for reaction taking place in alcohols the transition state probably contains two molecules of solvent but only one for the reaction in amines.     

Rotational structure in the infrared spectra of carbon dioxide and nitrous oxide dimers

High-resolution infrared predissociation spectra have been measured for dilute mixtures of CO₂ and N₂O in helium. Rotational fine structure is clearly resolved for both (CO₂)₂ and (N₂O)₂, the linewidths being instrument-limited. This establishes that predissociation lifetimes are longer than approximately 50 ns.     

Die Heterogenität von kristalliner Hefe-Alkoholdehydrogenase,nachgewiesen durch Stärkezelelektrophorese

Ohne Zusammenfassung     

Reissert compound studies. XXVII. The reaction of the anion with 4-piperidones

The anion of the isoquinoline Reissert compound has been found to react with 4-piperidones to give esters of tertiary alcohols.     

The kinetics of the decarboxylation of n-butylmalonic acid in alkanols and amines

Rate constants and activation parameters are reported for the decarboxylation of n-butylmalonic acid in four normal alkanols (hexanol? 1, octanol? 1, decanol? 1, and dodecanol? 1) and in five amines (aniline, N-methylaniline, N-ethylaniline, N-n-propylaniline, and N-n-butylaniline). Both ΔH? and ΔS? of the reaction in both homologous series decrease regularly with increasing length of the hydrocarbon chain of solvent. If we compare data for the reaction in alkanol–amine pairs containing the same total number of carbon atoms in the molecule, we find that the ΔH? values are identical, but that the value of ΔS? is 0.8 eu/mole higher for the reaction in the amines as compared with the alcohol. The rate constant, at all temperatures, is 1.5 times as large in the amine as it is in the corresponding alcohol. Empirical equations are deduced relating the parameters ΔH? ΔS? ΔG? and k of the reaction to the parameters n and T, where n is the total number of carbon atoms in the solvent molecule and T is the absolute temperature. The results reported herein are compared with previously reported data for malonic acid.     

Reissert compound studies. XXXI. Emetine analogs based on the reaction of the reissert anion with 1,3,4,6,7,11b-hexahydro-9, 10-dimethoxybenzo[a] quinolizin-2-ones

Reaction of the Reissert anion with the carbonyl group of 1,3,4,6,7,11b-hexahydro-9,10-dimethoxybenzo[a]quinolizin-2-one and with 3-ethyl-1,2,3,4,6,7-hexahydro-9,10-dimethoxy-11bH-benzo[a]quinolizin-2-carboxaldehyde give emetine analogs. This anion does not react with the carbonyl group of 3-aIkyl-1,3,4,6,7,11b-hexahydro-9,10-dimethoxybenzo[a]quinolizin-2-one but instead gives a rearrangement product and the benzoquinolizinone cyanohydrin.     

Photo-oxidation of unsaturated ferrocenyl-substituted carboxylic acids

In aqueous solution (pH 9) containing N₂O, the unsaturated acids $\text{trans}$-FcCHCH(CH₂)nCO₂H (n = 0 and 1) and FcCCCO₂H each undergo photo-oxidation, upon illumination with u.v. light of wavelength 240-250 nm, giving dipolar ferricenium species which may be chemically reduced back to the original acids. The mechanism of photo-oxidation, which is inhibited by ethanol, appears to be similar to that previously proposed for saturated ω-ferrocenylalkanoic acids.