A study of the process of lignification of one-year willow wood

Conclusions 1. The content of lignin in the wood ofSalix viminalis andSalix acutifolia increases with the growth of the shoots during shortened days and also in drier climatic periods.2. The monosaccharides, glucose, fructose, and arabinose take part in the synthesis of the lignin of young wood ofSalix viminalis andSalix acutifolia. The formation of lignin of one-year willow wood takes place from May to January (with a maximum in June–July). The content of methoxyl groups in it gradually rises.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 6, pp. 546–550, 1969     

The molecular structure of the N-chloroimine product of rearrangement of N,N-dichloroperfluoroaniline: A study by gas-phase electron diffraction

A gas-phase electron-diffraction study of the product of rearrangement of N,N-dichloro-perfluoroaniline has assisted in establishing it to be the N-chloroimine, I, rather than the azepine, II. The molecule is found to be planar apart from atoms Cl13 and F14. The detailed dimensions shown in Fig. 2 were obtained by least-squares refinements in which several structural constraints were applied to reduce the total number of independent parameters. Of particular interest is the evidence for overcrowding around the CN bond: ∠N7C1C2 = 128°, ∠C18N7C1 = 126°, ∠N7C1C6 = 118° ; the distance C18 β F9 is 2.73 Å.     

Arylation with aryllead triacetates produced in situ by mercury-lead exchange

Reaction of a diarylmercury with lead tetraacetate to give an aryllead triacetate has been found to be a rapid reaction. The in situ generation of aryllead triacetates is thus an attractive alternative to the use of the purified reagents in the various electrophilic arylation reactions of these compounds.     

Some investigations on the photostabilization of polypropylene

The effect of substituted hydroxybenzophenone, benzotriazole and organic metal complexes on the photooxidation of PP films has been studied. It has been established that NiDBTC added in 1.0 wt. % is the most effective photostabilizer.While in the case of other stabilizers there is a slight increase in the Co content even during the induction period, with the application of NiDBTC practically no oxidation can be observed before the stabilizer completely disappears. This means that NiDBTC inhibits the photooxidation of the polymer even in low concentration.

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, - . , Ni, 1,0 . %. . , Ni , . , Ni .

     

Study of air pollution particulates by X-ray photoelectron spectroscopy

Summary This paper discusses the application of X-ray photoelectron spectroscopy to the determination of the chemical composition of sulfur and nitrogen species in air pollution particulates. Core electron chemical shift measurements are augmented by the determination of relative concentrations and volatility of particulate species.

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Untersuchung von Verunreinigungsteilchen in der Luft durch Röntgenphotoelektronen-Spektroskopie

Zusammenfassung Die Anwendung der Röntgenphotoelektronen-Spektroskopie auf die Bestimmung der chemischen Zusammensetzung von Schwefel und Stickstoff enthaltenden Verunreinigungsteilchen in Luft wird diskutiert. Messungen der chemischen Verschiebung werden ergänzt durch die Bestimmung der relativen Konzentrationen und der Flüchtigkeit der Verbindungen.

Presented at the 6th Annual Symposium on Recent Advances in the Analytical Chemistry of Pollutants, April 21–23, 1976; Vienna, Austria.     

The reaction of 2-picoline N-Oxide with o-substituled benzoates and lsatoic anhydrides

The reaction of 2-picoline N-Oxide anion with o-substituted henzoates and isatoic anhydrides to give synthetically useful l-(2-methoxyphenyl)-2-(2-pyridinyl)ethanone N-oxides, I-(2-hydroxy-phenyJ)-2-(2-pyridinyl)ethanone N-oxides and I -(2-arninopheny])-2-(2-pyridinyl)ethanone N-oxides is described.     

Reaction of some sympathomimetic amines with sodium 1,2-naphthoquinone-4-sulphonate

Summary The condensation products of 4 sympathomimetic amines with 1,2-naphthoquinone-4-sulphonic acid have been prepared and examined. A spectrophotometric procedure based on the chloroform-soluble orange-red condensation product is described. The same products were investigated fluorimetrically after reduction with sodium borohydride. The results obtained are satisfactory.

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Zusammenfassung Die Kondensationsprodukte vier sympathicomimetischer Amine mit 1,2-Naphthochinon-4-sulfonsäure wurden dargestellt und untersucht. Ein spektralphotometrisches Verfahren auf der Grundlage des chloroformlöslichen, orangeroten Kondensationsproduktes wurde beschrieben. Die gleichen Produkte wurden auch fluoreszenzanalytisch nach ihrer Reduktion mit Natriumborhydrid untersucht. Die Ergebnisse sind befriedigend.

     

Medium-sized cyclophanes—XVII : Tetra-, hexa-, octa- and decahydropyrenes from [2.2]metacyclophane. Transannular dehydrogenation,isomerization, and disproportionation reactions by means of benzoyl peroxide,metal salts and sulfuric acids

[2.2]Metacyclophane (1) undergoes a variety of reactions according to the reagents and conditions. These include (1) substitution (path a), (2) transannular dehydrogenation (path b and c), (3) cycloisomerization (path d) and (4) transannular hydrogenation. A brief summary of these reactions is presented.The diversity of the reactions of 1 is further explored using benzoyl peroxide (BPO), cupric chloride, aluminum chloride, other metal salts, H₂SO₄ and FSO₃H. With BPO or cupric chloride, one-electron transfer mechanism is postulated. This involves a tautomeric ion pair formed by the intramolecular arylation with an aryl cation radical. A supporting evidence in favor of the mechanism is presented from experiments using various metal salts in different solvents.On the contrary, the reaction with aluminum chloride gives decahydropyrene (8) and octahydropyrene (11) together with cycloisomerization product 5 and dehydrogenation products 2, 3 and 4. When treated with AlCl₃HCl 1 gives similar products as above but the product ratios are quite different. The major product is 5 but only a trace amount of 8 is formed. The reaction with H₂SO₄ or FSO₃H also produce 2, 4, 5 and 11. Some mechanistic evidence in favor of the disproportionation reaction is presented.     

Vertical excitation as a transient phenomenon

For a particular model with two electronic states, each with two vibrations, the dipole correlation function governing electronic absorption is e ^?iωOt cosγt with spectrum ω ₀±γ. The function starts as e ^?iωOt (γ?ω ₀), with Fourier transform peaking around ω ₀ instead of ω ₀±γ, and this is associated with vertical excitation. After a time t～2/γ the spectrum goes over into the normal one. As a generalization, a procedure is outlined for characterizing the state reached first after interaction with light is initiated. Finally it is suggested that one can understand aspects of internal conversion by analogy with the case of vertical excitation.     

Qualitative features of the two-dimensional Raman spectrum in liquids

The theory presented earlier [J. Kim and T. Keyes, Phys. Rev. E 66, 051110 (2002)] is analyzed to determine the information available from the two-dimensional Raman spectrum R((5))(t(2),t(1)) in liquids. The known spectra are well represented by the sum of two products of ordinary time correlations predicted by the theory. The shape of R((5)) is related in general to the values of simple same-time averages and concepts amenable to physical intuition. Using standard models for the time correlations entering the theory, specific analytic expressions for the spectrum are obtained depending on two parameters and a time scale, and the behavior of the spectrum is mapped out in the parameter space.