Oscillation chemiluminescence in liquid phase oxidation of organic compounds

It is for the first time that distinct chemiluminescence oscillations have been observed in the liquid phase oxidation for the system: oxidative substrate — thermal initiator — photosensitizer — O₂. Oscillations and their parameters are dependent on the experimental conditions.

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: — — —O₂. .

     

A new Ba(OH)2 catalyst for synthesis of diacetone alcohol

The application of new Ba(OH)₂ catalysts for the preparation of diacetone alcohol is described. No loss of activity is observed when they are stored in a dessiccator over NaOH. The same yield as that described in the literature is obtained, but in a much shorter reaction time (9.5 h against 72–120 h)

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Ba(OH)₂ . NaOH . , , (9,5 72–120 ).

     

Selectivity of the steam reforming of methane over metallic catalysts

The activity and selectivity of the methane-steam reaction has been studied in a gradientless reactor at atmospheric pressure and 700–850 °C. Differences were found in the course of the reaction on Pd relative to other metals, viz. Ni, Pt and Ru, and an interpretation of the results is proposed.

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700–850°C. Pd , ., Ni, Pt Ru, .

     

Triterpene glycosides ofSophora japonica seeds

We have isolated from the seeds of Sophora japonica the known soyasaponogenol B-3-[O--D-glucopyranosyl-(12)-O--D-glucopyranuronoside] (adzukisaponin II), soyasapogenol B [3-O--galactopyranosyl-(12)-O--L-glucopyranuronoside] (soyasaponin III), soyasapogenol B 3-(O--L-rhamnopyranosyl-(12)-O--L-glucopyranosyl-(12)-O--D-glucopyranuronoside] (adzukisaponin V), soyasapogenol B 3-(O--D-rhamnopyranosyl-(12)-O--D-galactopyranosyl-(12)-O--D-glucopyranuronoside] (soyasaponin I), and the new glycoside (1) — soyasapogenol B 3-[O--D-glucopyranuronoside]. The structure of this glycoside has been established on the basis of the results of enzymatic, complete, and partial hydrolyses and¹³C NMR spectra.Simferopol' State University and Kursk State Medical Institute, Kursk. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 709–713, September–October, 1995. Original submitted March 3, 1995.     

Reaction between the OH group of hydroxyproline and diisocyanate catalyzed by an organotin compound

We have studied the kinetics of the reaction of L-hydroxyproline with OCH(CH₂)₆NCO, catalyzed by organotin, avoiding side reactions by protecting the other active hydrogens of the aminoacid, and comparing it with the MeOH/n-BuNCO system.

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L-- -OCN(CH₂)₆NCO, , . . - .

     

Catalytic activity of transition metal silicides in hydrogen oxidation

The catalytic activity of transition metal silicides in H₂ oxidation is much higher compared to metal-like carbides, which can be due to the lower electronegativity of silicon compared to carbon.

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, , .

     

A simple model for oscillations in a chain-branching reaction

A model of a chain-branching reaction with reactant consumption and regeneration is suggested to describe weakly damped oscillations. The number of variables in the model is two and the order of reactions steps is not more than two. Taking into account of the step of quadratic branching leads to the appearance of sustained oscillations (to the limit cycle).

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- , . , . ( ).

     

Study of hydrogen isotope exchange on calcium, strontium and barium hydrides

The isotope exchange of hydrogen on rare-earth metal hydrydes has been studied. When passing from Ca to Sr and Ba, the activation energy decreases and, correspondingly, the rate of exchange increases. A similar dependence is observed for the isotope exchange of oxygen on the corresponding oxides and of nitrogen on nitrides.

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. Ca Sr Ba . .

     

Determination of CO adsorption heats from kinetic data for CO hydrogenation over metals

Studies of catalytic CO hydrogenation following the Langmuir-Hinshelwood mechanism indicate that the observed decrease in the activation energy with increasing temperature is due to the decreased surface coverage with reactants. The relationships obtained permit to carry out approximate estimates for the adsorption heat of CO.

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CO, -, , . CO.

     

Spinels as heterogeneous catalysts for oxidation of water to dioxygen by tris-bipyridyl complexes of iron(III) and ruthenium(III)

Cobaltites, ferrites and chromites of some metals were found to be catalytically active in oxidation of water to dioxygen by trisbipyridyl complexes of Fe(III) and Ru(III). The possible catalytic action of surface compounds of hydroxide type is discussed.

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, , - (III) (III). .

     

Assay of nitro and nitroso compounds by solution thermochemistry

Some nitro and nitroso compounds have been determined by direct reduction with Ti(III) chloride without the necessity for degassing the analyte solutions. Methods have been developed for the determination of some binary mixtures by both enthalpimetry and catalytic thermometric titrimetry. The accuracy at the 0.1 mMole level is±1%, and the time taken for a single titration is less than 2 minutes.

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Zusammenfassung Einige Nitro- und Nitrosoverbindungen wurden durch direkte Reduktion mit Ti(III)-chlorid bestimmt, ohne dass die Notwendigkeit der Verdampfung der Analysenlösung besteht. Es wurden Methoden zur Bestimmung einiger binärer Gemische durch Enthalpimetrie und katalytische thermometrische entwickelt. Die Genauigkeit beträgt im Bereich von 0.1 mMol±1%, und eine Titration erfordert weniger als 2 Minuten.

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- . . 0,1 ± 1%, , 2 .

     

Synthesis of new condensed analogs of isoindolinium salts

Quaternary ammonium salts that contain a 3-(-naphthyl)propargyl group in addition to a group of the propargyl type undergo intramolecular cyclization of the diene-synthesis type under base-catalysis conditions to give condensed isoindolinium analogs.Communication 209 from the series Research on amines and ammonium compounds. See [1] for Communication 208.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 759–762, June, 1991.     

A calorimetric investigation into copper–arginine and copper–alanine solid state interactions

Complexes of formula CuCl₂ · 2arg and CuCl₂ · 4ala (arg = arginine; ala = alanine) were prepared at room temperature by a solid state route. The metal–amino acid solid state interactions were studied by i.r. spectroscopy and solution calorimetry. For both complexes, participation of the carboxylate group as well as nitrogen in coordination are inferred, based on the i.r. data. For the copper–arginine compound, the calculated thermochemical parameters are: _rH_m = –114.9 ± 1.42 and _fH_m = –1608.3 ± 11.6 kJ mol^–1. For copper–alanine compound, a complete set of thermochemical parameters were calculated: _rH_m = –18.0 ± 0.9; _fH_m = –2490.4 ± 4.3; _DH_m = 597.2 ± 17.7; _MH_m = 771.9 ± 18.7; _gH_m = 627.1 ± 22.3 and D (Cu–L) = 156.8 ± 5.7 kJ mol^–1. Based on _rH_m and dissolution enthalpy values, a stronger intermolecular solid state interaction can be inferred for the arginine complex, than for the alanine one complex, probably due to the formation of intermolecular hydrogen bonds in the former.     

Evaluation of triplet repulsion energies

The equation is suggested for predicting triplet repulsion energies. X=R–R^o, while R^o and¹V^o are the equilibrium bond length and the spectroscopic dissociation energy, respectively. Parameters and may be estimated from known bond properties.

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( X=R–R^o, a R^{o 1}V^o , . , .

     

Triterpene and steroid glycosides of the genusMelilotus and their genins II. Melilotoside D from the roots ofMelilotus albus

A new triterpene glycoside of the oleanane series — melilotoside D — has been isolated from the roots of plantMelilotus albus Medik. (Leguminosae). Melilotoside D is a tetraoside of soyasapogenol B. Its structure has been shown on the basis of chemical transformations and spectral characteristics as soyasapogenol B 3-O-{[O--L-rhamnopyranosyl-(12)]-[O--L-arabinopyranosyl-(13)]-O--D-galactopyranosyl-(12)--L-arabinopyranoside}.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 762–765, November–December, 1994.     

Testing thermal stabilities of base oils and their additives via high-temperature infrared spectroscopy

The thermal stabilities of base oils and their additives could be examined by employing an infrared spectroscopic technique. As the heat temperature was increased, changes in absorption were recorded at different wavelengths characteristic of the chemical groups. These changes were observed to occur slowly at first, but then turn to become more marked at specific temperatures. The magnitudes of these changes and temperatures were taken as indications of the thermal stabilities of the samples. The thermal stability was found to decrease in the following sequence: aromatics > naphthenes > hetero compounds > substituted aromatic rings > paraffins.

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Zusammenfassung Ziel der Arbeit ist die Untersuchung der thermischen Stabilität von Ölen und deren Additiven bei Temperaturen bis zu 250 °C. Die angewandte Technik beruht auf der Verfolgung der bei verschiedenen Temperaturen eintretenden Veränderungen der Infrarotspektren der getesteten Proben. Die Probe wird in eine spezielle, auf unterschiedliche Temperaturen aufheizbare IR-Zelle eingefüllt. Die Zelle wird zunächst direkt auf 80 °C aufgeheizt, danach wird in Abständen von 10 °C je ein Spektrum aufgenommen, bis eine Temperatur von 250 °C erreicht ist. Die Referenzzelle wird ebenfalls mit der zu untersuchenden Probe gefüllt, jedoch nicht aufgeheizt. Bemerkenswerte und sich klar unterscheidende Veränderungen in der Intensität von einigen, charakteristischen Gruppen chemischer Verbindungen zuzuordnenden Banden wurden beobachtet. Diese Veränderungen gehen zunächst langsam vor sich, werden dann aber bei spezifischen Temperaturen sehr schnell. Das Ausmaß dieser Veränderungen und die spezifischen Temperaturen unterscheiden sich für die verschiedenen Gruppen chemischer Verbindungen. Die thermische Stabilität nimmt in der Reihenfolge Aromaten >Naphthene> Heteroverbindungen > substituierte Aromaten > Paraffine ab. Ein Antioxidant-Additiv des Zinkdialkyldithiophosphat-Typs wurde ebenfalls getestet und bewertet.

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250°. , . . 80°, 10° 250°. , . , , . , . , , . > > > > . , .

     

Synthesis of potential antagonists to amino acids in the quinoline series

The following potential antagonists to amino acids were synthesized: -(6-quinolyl)--alanine, -(8-quinolyl)--alanine, and -(2-phenyl-4-carboxy-6-quinolyl)--alanine.     

Influence of HCl on butene isomerization catalyzed by ethanolic rhodium trichloride II. Calculation and interpretation of the rate constants of the triangle scheme

The values of the rate constants of the triangle scheme, calculated by means of a non-linear least-squares method, depend systematically on the HCl concentration. The alteration of the cis-trans selectivity expressed by the ratio k_1c/k_1t might indicate a change in the mechanism of isomerization with the HCl concentration.

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, , . - , k_1c/k_1t, .

     

Über das 2-Dichlormethyl-oxazolin und seine Kondensation mit 4-Nitrobenzaldehyd

Zusammenfassung N-Dichloracetyläthanolamin (I) wurde über das mit SOCl₂ erhaltene N-Dichloracetyl--chloräthylamin (II) durch Alkali in das 2-Dichlormethyl-oxazolin (III) übergeführt, dessen sehr leicht erfolgende hydrolytische Umwandlungen beschrieben werden. Kondensation von 4-Nitrobenzaldehyd mit (III) erfolgt ohne jedweden Katalysatorzusatz unter den mildesten. Bedingungen an der überaus reaktiven Methingruppe des Dichlormethylrestes von (III) zu 2-[-(4-Nitrophenyl)--oxy-, -dichloräthyl]-oxazolin (VI), dessen Konstitution an Hand eines O-Acetats und durch die saure Hydrolyse zu einer -(4-Nitrophenyl)-, -dichlorhydracrylsäure und Äthanolamin bewiesen wird.Herrn Prof. Dr.L. Ebert zum 60. Geburtstag gewidmet.     

Infrared study of the adsorption and reactions of nitric oxide on CuY zeolites

The adsorption and the reactions of nitric oxide on CuY zeolites with copper ions in various states have been studied by IR-spectroscopy. Forms of NO adsorbed on individual Cu²⁺ ions, on weak and strong magnetic formations, and on Cu⁺ ions have been observed. Processes of oxidation and reduction of NO to NO₂, N₂O and N₂ occurring on CuY zeolites are discussed. Adsorption of nitrogen on coordinatively unsaturated copper ions has been observed.

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- CuY . NO Cu²⁺, Cu¹⁺. --, CuY NO₂, N₂O N₂. .