Isolation,purification, and characterization of cyclomaltodecaose (ε-CD)

-Cyclodextrin (-CD) is a cyclic oligosaccharide, composed of ten -1,4-linked D-glucoses reported by Frenchet al. in 1965¹⁾, but has not been studied because of the difficulty in the preparation and purification of large-ring CDs composed of more than nine -1,4-linked D-glucose units. This report describes the purification and characterization of -CD. Furthermore, the crystal and molecular structure of -CD hydrate -CD 19H₂O) was elucidated by X-ray analysis.     

The electronic spectrum of acrylonitrile

The vapor absorption spectrum of acrylonitrile CH₂CHCN has been measured in the vacuum ultraviolet region. In addition, an all-valence-electron molecular orbital calculation has been used to calculate the electronic structure and spectrum of the molecule. On the basis of the MO calculation, as well as a vibrational analysis of the observed spectrum, several electronic transitions are assigned. The lowest energy absorption band (2107Å, = 150) is assigned as an n ^* transition. Absorption bands at 2030Å (=1600), 1725Å ( = 2100), and 1570Å ( = 1920) are assigned as 0–0 bands associated with transitions that are, respectively, ^*,^*, and ^* in character.

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Zusammenfassung Das UV-Absorptionsspektrum von dampfförmigen Acrylnitril wurde gemessen und eine CNDO/2-Rechnung für die Elektronenstruktur durchgeführt. Auf dieser Basis konnten unter Zuhilfenahme der Analyse der Schwingungsstruktur im beobachteten Spektrum mehrere Banden zugeordnet werden: die 2107-Å-Bande ( = 150) einem n^*-Übergang, die drei Banden bei 2030Å ( = 1600), 1725Å ( = 2100) und 1570 Å ( = 1920)0-0-Übergängen von ^*-, ^*- bzw. ^*-Banden.

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Résumé Mesure du spectre d'absorption en phase vapeur de l'acrilonitrile CH₂CHCN dans la région de l'ultraviolet. Par ailleurs, la structure électronique et le spectre de la molécule ont été calculés à l'aide d'une méthode des orbitales moléculaires semi-empirique pour tous les électrons de valence. Sur cette base, ainsi que sur une analyse vibrationnelle du spectre expérimental, on procède à l'attribution de plusieurs transitions électroniques. La bande d'absorption de plus basse énergie (2107 Å, = 150) est attribuée à une transition n ^*. Les bandes d'absorption à 2030Å ( = 1600), 1275Å ( = 2100) et 1570Å ( = 1920) sont considérées comme des bandes 0 - 0 associées à des transitions ^*, ^* et ^* respectivement.

     

The relative permittivity of 1,2-dimethoxyethane and N,N-dimethylformamide mixtures from −10 to 40°C

Binary solutions of N,N-dimethylformamide and 1,2-dimethoxyethane have been investigated by means of dielectric measurements at temperatures ranging from –10 to +40°C, and for nine mixtures covering the whole miscibility field expressed by the mole fraction of one component (0X₁1). The experimental data were used to study the dependence of on T and X₁, of the type = (T), = (X₁), and = (T,X₁). Further, the excess mixing function _E has been evaluated in order to identify particular patterns of interaction between unlike molecules and any other factor that could modify such patterns. The minimum in the _E vs. composition plots suggests the formation of an adduct of stoichiometric ratio DMFDME=11 at all the investigated temperatures.     

Kinetic analysis of thermogravimetric data. XI thermal decomposition of some metal dithionates

A thermal analytical study of Li, Na, K, Rb, Cs, NH₄, Mg, Ca, Sr, Ba and Zn dithionates is reported. The decomposition of the dithionate ion is endothermic in the case of the Na, K, Rb, Cs and NH₄ salts, but exothermic with Li, Mg, Sr, Ba and Zn. Kinetic parameters have been derived from the TG curves by means of the Coats-Redfern method. The validity of a linear kinetic compensation law is reported for the loss of crystal water and separately for the decomposition of the dithionate ion.

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Zusammenfassung Es wird über eine thermoanalytische Untersuchung der Dithionate von Li, Na, K, Rb, Cs, NH₄, Mg, Ca, Sr, Ba und Zn berichtet. Die Zersetzung des DithionatIons ist im Falle von Na, K, Rb, Cs und NH₄-Salzen endotherm, im Falle von Li, Mg, Sr, Ba und Zn hingegen exotherm. Die kinetischen Parameter wurden aus den TG-Kurven mittels der Coats-Redfern-Methode abgeleitet. Es wird über die Gültigkeit eines linearen kinetischen Kompensationsgesetzes für den Verlust von Kristallwasser berichtet und gesondert für die Zersetzung des Dithionat-Ions.

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Résumé On présente les résultats d'une étude par analyse thermique des dithionates de Li, Na, K, Rb, Cs, NH₄, Mg, Ca, Sr, Ba et Zn. La décomposition est endothermique dans le cas des sels de Na, K, Rb, Cs et ammonium tandis qu'elle est exothermique dans le cas des sels de Li, Mg, Sr, Ba et Zn. Les paramètres cinétiques sont déduits des courbes TG par la méthode de Coats-Redfern. La validité d'une loi de compensation cinétique linéaire est étudiée pour la perte de l'eau d'hydratation ainsi que pour la décomposition de l'ion dithionate.

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Li, Na, K, Rb, Cs,. NH₄, Mg, Ca, Sr, Ba Zn. [ Na, K, Rb, Cs NH₄ , Li, Mg, Sr, Ba Zn . - . .

     

Dielectric study of poly(methyl methacrylate) microcapsules in particular reference to the effect of the frequency dependence of the permittivity of the capsule wall

The dielectric behavior of poly(methyl methacrylate) (PMMA) microcapsules was analyzed theoretically by taking account of the frequency dependence of the relative permittivity _s and the electrical conductivity _s of the capsule wall. For comparison, similar analysis was applied to polystyrene (PS) microcapsules which have frequency-independent _s and _s . The behavior of _s and _s of the PMMA microcapsules was assumed to be represented by a dielectric relaxation of them-th power type on the basis of dielectric data on underwater PMMA films. By means of a theory of the interfacial polarization, some consideration was carried out regarding the effect of the frequency dependence of _s and _s on the dielectric behavior of the PMMA microcapsules. The consideration led to predictions that the frequency dependence of _s and _s causes (i) the variation in the relaxation intensity with the change in the conductivity of suspending medium, (ii) the frequency dependence of the permittivity at low frequencies and (iii) the frequency dependence of the conductivity at high frequencies. The theoretical prediction (i) was verified by observed data, (ii) and (iii) remaining unverified owing to the experimental difficulty.     

Effect of temperature of calcining hydrated aluminium oxides on their sorption properties

The effect of the temperature of calcining hydrated aluminium oxides on their sorption properties was investigated.It was found that the sorption properties and the porous structure of aluminium oxides depend on the type of material calcined and on the conditions under which this process occurs.

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Zusammenfassung Es wurde der Effekt der Kalzinierungstemperatur von hydratiertem Aluminiumoxid auf dessen Sorptionseigenschaften untersucht. Es wurde festgestellt, daß die Sorptionseigenschaften und die Porenstruktur von Aluminiumoxid von Typ des kalzinierten Materials und von den Bedingungen abhängen, unter denen dieser Prozess abläuft.

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. , .

     

Thermal and some other properties of the complexes crystallizing from the system Ni(II)-en-[Ni(CN)4]2−-H2O

Seven complex compounds exhibiting the compositions Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) and-Ni(en)₂Ni(CN)₄ (VII) were prepared from the system Ni-en-[Ni(CN)₄]^2–-H₂O. These compounds were examined by the methods of infrared spectroscopy, X-ray powder diffractometry, UV-VIS reflectance spectroscopy, and also by the measurement of magnetic moments. The thermal stability, the stoichiometry of thermal decomposition and the mutual transformations were investigated with a derivatograph. The reactions proceeding according to the following schemes were observed if the system was heated to appropriate temperature: (I)(II)(III)(V)(IV) and (VI)(VII)(III)(V)(IV) Process (VII)(III) represents isomerization. The reversibility of the process (V)(IV) is due to the high hygroscopicity of the anhydrous complex. The changes in structure in the course of the individual processes are discussed.

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Zusammenfassung Aus einem System Ni-en-[Ni(CN)₄]^2–-H₂O wurden sieben Komplexe der Formeln Ni(en)₃Ni(CN)₄·H₂O (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄·2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2.5H₂O (VI) und-Ni(en)₂Ni(CN)₄ (VII) hergestellt. Diese Verbindungen wurden mittels IR-Spektroskopie, Röntgenpulverdiffraktometrie, UV-Reflexionsspektroskopie und durch Messungen des magnetischen Momentes untersucht. Die Wärmestabilität, die Stöchiometrie des thermischen Zerfalles und die gegenseitigen Umwandlungen wurden mittels eines Derivatographen untersucht. Wird das System auf geeignete Temperaturen erhitzt, kann der Reaktionsverlauf durch folgendes Schema dargestellt werden: (I)(II)(III)(V)(IV) und (VI)(VII)(III)(V)(IV).Der Prozeß (VII)(III) verkörpert eine Isomerisierung. Die Umkehrbarkeit von Prozeß (V)(IV) ist auf die ausgeprägten Hygroskopieeigenschaften des wasserfreien Komplexes zurückzuführen. Es werden die im Ablaufe der einzelnen Prozesse vorgehenden Strukturveränderungen besprochen.

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Ni- -[No(N)]² -₂ Ni(en)₃Ni(CN)₄ · ₂ (I), Ni(en)₃Ni(CN)₄ (II),-Ni(en)₂Ni(CN)₄ (III), Ni(en)Ni(CN)₄-2H₂O (IV), Ni(en)Ni(CN)₄ (V), Ni(en)₂Ni(CN)₄ · 2,5H₂O (VI) -Ni(en)₂Ni(CN)₄ (VII). , , - , . , . (I)(II)(III)(V)(IV) (VI)(VII)(III)(V)(IV). (VII)(III) . (V)(IV) . .

     

Analysis of correlation effects in HeI,LiI and BeI iso-electronic sequences by Z-expansion methods

Correlation effects for the energy and the expectation values of the electron-nuclear attraction and the inter-electronic repulsion in atomic states are discussed in terms of Z expansions for these quantities. Numerical examples are given for the HeI, LiI and BeI iso-electronic sequences.It is shown that a series expansion of the type V _en =2₀Z² + ₁Z (a.u.) gives very accurate results for the expectation value of the electron-nuclear attraction.

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Zusammenfassung Der Korrelationsanteil an der Energie und an den Erwartungswerten der Elektron-Kernanziehung sowie der Elektronenabstoßung für atomare Zustände wird mit Hilfe der Z-Entwicklung dieser Größen diskutiert. Für die isoelektronischen Reihen HeI LiI und BeI werden numerische Beispiele angegeben. Es wird gezeigt, daß eine Reihenentwicklung vom Typ V _en +2Z² + ₁Z(a.E.) sehr genaue Ergebnisse für den Erwartungswert der Elektron-Kernanziehung liefert.

     

Eigenvalues of the real generalized eigenvalue equation perturbed by a low-rank perturbation

The low-rank perturbation (LRP) method solves the perturbed eigenvalue equation (B +V) _k = _k (C +P) _k , where the eigenvalues and the eigenstates of the related unperturbed eigenvalue equationB _i = _i C _i are known. The method is designed for arbitraryn-by-n matricesB, V, C, andP, with the only restriction that the eigenstates _i of the unperturbed equation should form a complete set. We consider here a real LRP problem where all matrices are Hermitian, and where in addition matricesC and (C +P) are positive definite. These conditions guarantee reality of the eigenvalues _k and _i . In the original formulation of the LRP method, each eigenvalue _k is obtained iteratively, starting from some approximate eigenvalue _k . If this approximate eigenvalue is not well chosen, the iteration may sometimes diverge. It is shown that in the case of a real LRP problem, this danger can be completely eliminated. If the rank of the generalized perturbation {V, P} is small with respect ton, then one can easily bracket and hence locate to any desirable accuracy the eigenvalues _k (k = 1, ...,n) of the perturbed equation. The calculation of alln eigenvalues requiresO(² n ²) operations. In addition, if the perturbation (V, P) is local with the localizabilityl p, then onlyO(² n) operations are required for a derivation of a single eigenvalue.     

Catalysts for selective hydrogenation of conjugated dienes into olefins in the presence of PdCl2 complexes

Complexes of PdCl₂ with amines or pyridine reduced by (iso-Bu)₂ AlH are shown to be catalytically active in the selective hydrogenation of conjugated dienes into olefins in aromatic media. The promoting effect of H₂O and O₂ has been established.

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PdCl₂ , (-Bu)₂ AlH, . H₂O O₂.

     

Vibrational isotope effect of linear and planar molecules: Deuterated bromoethenes

Linear (planar) molecules A and B which are identical except for isotopic substitutions at the atomic sites are considered. Stretching (bending, out-of-plane) frequencies _k and normal modes _k of the isotopically perturbed molecule B are expressed in terms of stretching (bending, out-of-plane) frequencies _i and the corresponding normal modes _i of the unperturbed molecule A. Complete specification of the unperturbed normal modes is not required. All that is needed are stretching (bending, out-of-plane) amplitudes | _i of the normal modes _i at those sites that are affected by isotopic substitution. The rule which interlaces frequencies _k of molecule A with frequencies _i of molecule B is derived. Given two isotopic molecules A and B that differ by a single isotopic substitution at site , the inversion relation is derived. This relation expresses unperturbed stretching (bending, out-of-plane) amplitudes at the site in terms of stretching (bending, out-of-plane) frequencies of molecules A and B . As an example, out-of-plane vibrations of deuterated bromoethene were considered. In the simplest method 12 out-of-plane frequencies of four polydeuterated bromoethenes were calculated from 12 out-of-plane frequencies of bromoethene and three monodeuterated bromoethenes. Standard deviation of thus calculated frequencies from experimental frequencies is =2.74 cm^–1. In another method, 15 out-of-plane frequencies of four polydeuterated bromoethenes and selected monodeuterated bromoethene are calculated from 9 out-of-plane frequencies of bromoethene and the remaining two monodeuterated bromoethenes. Depending on which monodeuterated bromoethene is selected (1-, cis- or trans-), standard deviation of thus obtained frequencies from experimental frequencies is 1=2.84 cm^–1, c=2.96 cm^–1 and t=2.72 cm^–1.     

Temperature and velocity fields in a gas stream exiting a plasma torch. A mathematical model and its experimental verification

A mathematical model was developed to predict the velocity and temperature fields in a free plasma jet issuing from a D.C. plasma torch. It was assumed that the temperature and velocity at the torch nozzle were specified and the turbulent Navier-Stokes equations were solved in conjunction with a two-equation model of turbulence and the energy transport equation. The model was formulated in terms of the two-dimensional elliptic equations to facilitate its future extension to nonparabolic problems. The predictions of the model were compared with experimental measurements obtained from laser Doppler and spectroscopic techniques. Good overall agreement was found between the theoretical predictions and the experimental measurements for two sets of initial conditions corresponding to nitrogen/hydrogen and argon/hydrogen plasmas. Radiation was found to have a small effect on the overall heat transfer process, and it is suggested that the assumption of an optically thin radiation loss per unit volume is sufficiently accurate for most engineering applications. The significance of this work lies in the fact that, for the first time, it is possible to test the assumptions of the current model against a reliable set of experimental measurements.Notation C ₁,C ₂,C _D constants inK- turbulence model, Table III - C _P average specific heat of plasma at constant pressure - h ₁ length of integration region - h ₂ width of integration region - K turbulent kinetic energy per unit mass - P pressure - r radial coordinate - R ₀ internal radius of anode - S _K source term forK equation - S _R radiation loss per unit volume - S source term for equation - T ₀ temperature of plasma atz=0 - T temperature of plasma - T _a ambient temperature - u velocity inz direction - u ₀ velocity of plasma atz=0 - v radial velocity of plasma - z axial coordinate - dissipation rate of turbulence energy - , _eff, _t molecular, effective, and turbulent viscosities, respectively - density - _K, _T, Prandtl numbers forK, T, and, respectively     

Dehydration-dehydrogenation of 1- and 2-butanols on lanthanide oxide catalysts

Catalytic decomposition of 1- and 2-butanols on the rare earth oxides CeO₂, Pr₆O₁₁, and Me₂O₃ (Me=La, Sm, Eu, Dy, Ho and Yb) has been studied. Dehydration-dehydrogenation selectivity of these oxides was analyzed from the point of view of the fractional selectivity (S_F). For the decomposition of 2-butanol and the product distribution on the lanthanide oxides, preferential orientation to Hofmann olefin as well as a cis/trans ratio slightly higher than that of the equilibrium value is observed.

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1- 2- CeO₂, Pr₆O₁₁ Me₂O₃ (Me=La, Sm, Eu, Dy, Ho Yb). - (S_F). 2- , , / .

     

Influence of substituents on rate constants for recombination of tertiary peroxy radicals

A linear correlation between the logarithm of rate constant (2k_t) for recombination of tertiary peroxy radicals (ROO)^* and ^* constants of substituents R was found to be 1g 2k_t=lg 2k _t ^° . The calculated values are 1g 2k _t ^° =4.59±0.08 and ^*=5.56±0.35.

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I (2k_t) (ROO) R: 1g 2k_t=lg 2k _t ^° . , 1g 1g 2k _t ^° =4,59±0,08 =5,56±0,35

     

Propos sur l'interpretation de l'energie d'activation experimentale

Résumé Les résultats de divers travaux montrent que la valeurE _e de l'énergie activation expérimentale tirée des diagrammes d'Arrhénius varie avec la pression, dans le cas de réactions de décompositions endothermiques.L'analyse de divers modèles permet d'expliquer cette constatation en montrant que la grandeurE _e n'a pas le sens d'une énergie d'activation mais est une fonction de nombreux paramètres. Deux d'entre eux ont été retenus dans le cadre de cette étude: le terme d'écart à l'équilibre et le terme de gradient thermique, provoqué par l'endothermicité du phénomène.Cette analyse permet d'établir une prévision de la fonctionE _e (P) conforme aux résultats expérimentaux.

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The results from various investigations show that the experimental activation energy valueE _e derived from the Arrhenius diagrams varies with pressure for endothermic decomposition reactions.The analysis of various models allows this fact to be accounted for by showing thatE _e should be regarded not in its fundamental formulation, but as being a function of numerous parameters. Two of these were taken into account in the present study, i.e. deviation from equilibrium and a thermal gradient due to the fact that the phenomenon is endothermic.FunctionE _e (P) fitting the experimental results may be predicted by such an analysis.

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Zusammenfassung Die Ergebnisse verschiedener Untersuchungen zeigen, dass die aus den Arrhenius-Diagrammen abgeleiteten experimentellen Werte der AktivierungsenergieE _e bei endothermen Zersetzungsreaktionen mit dem Druck variieren.Die Analyse verschiedener Modelle ermöglicht eine Erklärung dieser Tatsache, indem gezeigt wird, dassE _e nicht in ihrer grundliegenden Formulierung betrachtet werden darf, sondern als Funktion einer Anzahl von Parametern. Zwei dieser Parameter wurden in der vorliegenden Untersuchung berücksichtigt d.h. die Abweichung von dem Gleichgewicht und der thermische Gradient, welcher infolge der endothermen Beschaffenheit der Erscheinung auftritt.Eine den Versuchsergebnissen entsprechende FunktionE _e (P) kann mittels einer solchen Analyse vorausgesagt werden.

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, _e, , . , _ee , . , : , , . _e (), , .

     

Mass spectral and thermogravimetric studies of some iron(III) binuclear complexes with bridging thiuram disulfide ligands

Mass spectral and thermal studies by TG and DTG of some iron(III) binuclear complexes of the general type Fe₂(R₂dtc)₂(tds)X₂X/ have been carried out to determine their modes of decomposition. Fragmentation patterns are given and possible mechanisms are discussed.

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Zusammenfassung Massenspektrometrische und thermische Untersuchungen (TG und DTG) einiger zweikerniger Eisen(III)-Komplexe des allgemeinen Typs (R₂dtc)₂(tds)X₂X₂ wurden ausgeführt, um deren Zersetzungsmechanismus zu ermitteln. Fragmentspektren werden angegeben und mögliche Mechanismen diskutiert.

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- ( ) Fe₂(R₂dtc)₂(tds)X₂X₂ . .

     

Some mathematical aspects of nonisothermal kinetics

The results of an attempt to derive correct nonisothermal kinetic equations from isothermal ones through the classical nonisothermal change (CNC) of the postulated primary kinetic equations are presented. An alternative possibility through use of the model of infinitesimal isothermal portions (MIIP) is discussed.

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Zusammenfassung Die Autoren stellen die Ergebnisse eines Versuchs vor, korrekte Gleichungen für die nicht-isotherme Kinetik durch den klassischen nichtisothermen Übergang aus den als primär postulierten isothermen kinetischen Gleichungen abzuleiten. Als alternative Möglichkeit wird das Modell der infinitesimalen isothermen Abschnitte diskutiert.

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Quinazolines

A method was developed for the preparation of 2,3-polymethylene-3,4-dihydro-4-quinazolones with substituents in the benzene and polymethylene chains by reaction of anthranilic acid and its substituted derivatives with -butyro-, 5-phenyl--butyro-, -capro-, and -chloro--caprolactams in the presence of dehydrating agents. The corresponding quinazolines were obtained by reduction of the synthesized quinazolones.See [1] for communication V.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1564–1569, November, 1976.