Thermal study of some sulphosuccinates

The thermal properties of some sulphosuccinates and their intermediates were studied by using combined dynamic thermal analysis and mass spectrometry. The temperature ranges were similar in the two methods, and a scheme of thermal decomposition of the compounds investigated was suggested. In the first temperature range of thermal decomposition of the sulphosuccinate a-rupture of the molecular ion occurs. In the second temperature range, the fragmentation proceeds in two directions: either-rupture of the ethoxylated nonylphenol, or-rupture of the acid residue of the sulphosuccinates.

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Zusammenfassung Mittels einer Kombination von dynamischer Thermoanalyse und Massenspektroskopie wurden die thermischen Eigenschaften einiger Sulfosukzinate und deren Zwischenprodukte untersucht. Im ersten Temperaturbereich der thermischen Zersetzung des Sulfosukzinates findet eine-Spaltung des Molekülions statt. Im zweiten Temperaturbereich tritt auch ein alternativer Fragmentierungsweg auf: eine-Spaltung des Säurerestes des Sulfosukzinates.

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- . . - -. : - - .

     

ESR spectra of O2? on SnO2. effect of adsorbed CO on the conditions of stabilization of O2?

The physical adsorption of CO molecules on SnO₂ is shown to be accompanied by a reversible change in the ESR parameters of CO ₂ ^– anion radicals. The effect of CO is different for SnO₂ samples with different life histories.

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, CO SnO₂ - O ₂ ^– , CO SnO₂ .

     

Derivatives of 3-aminopiperidine-2, 6-dione

Several N-substituted 3-phthalimidopiperidine-2,6-diones and 3-(3phthalimido-2,5-dioxopyrrolid-1-yl)piperidine-2,6-dione have been synthesized.     

Monohalogenobenzoylhydrazones VI. New antimony(III) complexes with monochlorobenzoylhydrazones of 2-furaldehyde, 2-pyrrolaldehyde and 2-thiophenaldehyde as ligands

The antimony(III) trihalides, SbX₃ (X=Cl, Br and I), react with the title ligands to give the compounds SbX₃L, where L=benzoyl- and monochlorobenzoylhydrazones of 2-furaldehyde (FBHH and FClBHH), 2-pyrrolaldehyde (PBHH and PClBHH) and 2-thiophenaldehyde (TBHH and TClBHH). The characterization of the new species was based on their elemental analyses, spectral data (IR and UV-Vis) and thermal studies. The ligands appear to offer two coordination sites (the carbonyl and azomethine groups) and perhaps a third one (the heteroatom of the heterocyclic ring). The thermal decompositions of the studied complexes proceed via one or three stages, the number of stages depending on the nature of both the hydrazones and the halogens. The structures proposed for the investigated complexes are either pseudo- or distorted octahedral.

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Zusammenfassung Antimon(III)-trihalogenide, SbX₃ (X=Cl, Br und I) reagieren mit den Titelliganden und liefern Verbindungen der allgemeinen Formel SbX₃L (L=Benzoylbzw. Monochlorobenzoylhydrazon von 2-Furfuraldehyd (FBHH und FClBHH), von 2-Pyrrolaldehyd (PBHH und PClBHH) und von 2-Thiophenaldehyd (TBHH und TClBHH). Die neuen Verbindungen wurden mittels Elementaranalyse, Spektraldaten (IR und UV) sowie thermischen Untersuchungen beschrieben. Zwei Koordinationsstellen scheinen von den Liganden bevorzugt zu sein: die Carbonylund die Azomethingruppe. Eine dritte könnte das Heteroatom des heterocyclischen Ringes sein. Die thermische Zersetzung der untersuchten Komplexe vollzieht sich in Abhängigkeit von der Natur der Hydrazone und der Halogene in einem oder in drei Schritten. Als Struktur für die untersuchten Komplexe wird eine pseudo-oder verzerrte oktaedrische Struktur vorgeschlagen.

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SbX ₃ (X=Cl, Br, I) - , 2- 2- , SbX ₃ L. , ( ), . , , . . .

     

Comparative study of the activity of Al?Pd and Al?Pt catalysts in deep oxidation of hydrocarbons

Atomic catalytic activity of palladium has been revealed to be higher than that of platinum in deep oxidation of methane and lower in the case of butane. According to the experimental data and the quantum-chemical calculation, the observed effects are ascribed to the different bond strength of the surface oxygen due to different reaction conditions.

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, _{Pd Pt}, . _{Pd Pt} - , .

     

Proanthocyanidins of Polygonum coriarium. I

Six proanthocyanidins have been isolated from the roots ofPolygonium coriarium. The structures of three oligomeric proanthocyanidins have been established: taranin, consisting of [epigallocatechin gallate]-(48)-[epigallocatechin gallate]-(48)-[epigallocatechin-(48)-epigallocatechin₂-(48)-epigallocatechin; taranoside A - [epigallocatechin gallate]-7-0-[-(16)--D-Glcp]₃-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-gallocatechin; and taranoside B - [epigallocatechin gallate]-7-O-[-(16)--D-Glcp]₄-(48)-[epigallocatechin-(48)-epigallocatechin]₂-(48)-epigallocatechin-(48)-[epigallocatechin gallate).Institute of the Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 59–67, January–February, 1992     

Chlorination of V2O5 by CCl4. The proposed reaction mechanism

Initial stage of the reaction of CCl₄ with V₂O₅ has been studied by MS and XPS techniques. According to the proposed mechanism dissociatively chemisorbed CCl₄ transforms to CO₂ via adsorbed COCl₂, while surface vanadium atoms involved are gaining step by step two chlorine atoms before the formation of the volatile end-product VOCl₃.

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CCl₄ V₂O₅ . - CCl₄ CO₂ COCl₂, VOCl₃.

     

Triterpene glycosides ofHedera taurica. XI. Structures of taurosides St-G1, St-H1, and St-H2 from the stems of Crimean ivy

The previously known glycosides 3-O--L-arabinopyranosyl-28-O-[-L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl]hederagenin and 3-O-[-L-rhamnopyranosyl-(12)-O--L-arabinopyranosyl]-28-O-[-L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl]hederagenin and the new triterpene glycoside tauroside St-H₁ — 3-O--D-glucopyransyl-28-O-[-L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl]hederagenin — have been isolated from the stems ofHedera taurica Carr.M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 571–579, July–August, 1993.     

Preparation of cobalt doped γ-Fe2O3 and Mn-Zn ferrites by the thermal decomposition of the hydrazine precursors

Fine particle cobalt doped-Fe₂O₃ and Mn-Zn ferrites have been prepared by the thermal decomposition of N₂H₅Co _x Fe_1–x (N₂H₃COO)₃.H₂O wherex=1–10 atom% and (N₂H₅)₃Mn_xZn_1–x Fe₂(N₂H₃COO)₉· 3H₂O wherex=0.2–0.8, respectively. Formation of these oxide materials has been confirmed by thermogravimetry and X-ray powder diffraction patterns. The fine particle nature of these oxide materials is evident from particle size analysis and surface area measurements.

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Zusammenfassung Mit fein verteiltem Kobalt versetztes-Fe₂O₃ sowie Mn-Zn Ferrite wurden durch thermische Zersetzung von N₂H₅Co _x Fe_1–x (N₂H₃COO)₃·H₂O mit jc=1–10 Atomprozent bzw. (N₂H₅)₃Mn _x Zn_1–x Fe₂(N₂H₃COO)₉·3H₂O mitx=0,2–0,8 hergestellt. Die Bildung dieser Oxidstoffe wurde durch Thermogravimetrie und Pulverdiffraktionsmethoden bekräftigt. Die Feinkornstruktur dieser Oxidstoffe wird durch Korngrößenverteilungs- und Oberflächenmessungen augenscheinlich.

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N₂H₅Co _x Fe_1–x (N₂H₃COO)₃·H₂O, x-1–10 %, (N₂H₅)₃Mn _x Zn_1–x Fe₂(N₂H₃COO)₉ · 3H₂O, x=0,2–0,8, , , -Fe₂O₃ Mn-Zn . . .

     

Triterpene glycosides ofHedera taurica XVI. Structures of glycosides St-A, St-B1, St-B2, St-C, St-D1, St-D2, St-E, St-F1, and St-F2 from the stems of Crimean ivy

From the stems of Crimean ivyHedera taurica Carr. (fam. Araliaceae) we have isolated previously known glycosides of oleanolic acid — the 3-O-[O--L-rhamnopyranosyl-(12)--L-arabinopyranoside], the 3-O--D-glucopyranuronoside, and the 3-O-[O--D-galactopyranosyl-(12)--D-glucopyranuronoside]; known glycosides of hederagenin — the 3-O--L-arabinopyranoside, the 3--D-glucopyranoside, the 3-O-[O--D-glucopyranosyl-(12)-O--L-arabinopyranoside], and the 3-O--D-glucopyranuronoside; and also the new triterpene glycoside St-D₂, hederagenin 3-O-[O--L-rhamnopyranosyl-(12)--D-glucopyranoside].Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 411–416, May–June, 1997.     

Effect of hydrolysis catalyst and thermal treatment on titania synthesis via sol-gel

The effect of acidic and basic catalysts and of thermal treatment on the preparation of TiO₂ by the sol-gel method has been studied. The resultant solids were characterized by UV-Vis spectroscopy. A displacement of the band due to a fundamental transition to lower energies was observed when acid catalysts were used.

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, TiO₂ - . . .

     

Calorimetric study of the BrO3?/Ce4+/cyclohexanone and BrO3?/Ce4+/cyclopentanone oscillating systems

The heat output (Q) during the induction period of a Belousov-Zhabotinskii oscillating reaction usually evolves at a constant rate /6/; we observe in the BrO ₃ ^– /Ce⁴⁺/Cyclohexanone system a sudden change in the slope of the function Q=f(t), which corresponds to the beginning of the quasistationary phase /3/.

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(Q) - ; BrO ₃ ^– /Ce⁺⁴/ Q=f(t), .

     

Kinetic analysis of thermogravimetric data. XX. Study of the thermal decomposition of some tetrathiocyanato-diamino-chromate complexes with derivatograph

The thermal decompositions of 8 complexes of the type A · H[Cr(NCS)₄(am)₂] (A=NH₃, pyridine,-picoline or aniline, andam=NH₃ or aniline) and of 14 complexes of the type M[Cr(NCS)₄(am)₂] (M=K, Ag, Tl, 1/2 Cd, 1/2 Pb or 1/3 Bi, andam=NH₃, benzylamine or aniline derivatives) were studied by means of a derivatograph. In the case of the A · H salts the formation of Cr(NCS)₃ was observed as a labile intermediate. Characteristic temperatures are discussed in terms of the polarizing effect of the outer sphere cations and of the nucleophilic character of the ligands. The results are compared with those obtained in the thermal decompositions of the analogous salts of the complex acid H₃[Cr(NCS)₆].

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Zusammenfassung Die thermische Zersetzung von 8 Komplexverbindungen des Typs A ·H[Cr(NCS)₄(am)₂] (A=NH₃, Pyridin, -Picolin, Anilin und am=NH₃ und Anilin) und von 14 Komplexen des Typs M[Cr(NCS)₄(am)₂] (M=K, Ag, Tl, 1/2 Cd, 1/2 Pb, 1/3 Bi und am=NH₃, Anilin und Anilinderivate) wurde mit dem Derivatographen untersucht. Im Falle der A. H Salze wird die Bildung von Cr(NCS)₃ als labiles Zwischenprodukt beobachtet. Die charakteristischen Temperaturen und kinetischen Parameter werden abgeleitet und auf der Basis der molekularen Struktur erörtert. Im Falle der M Salze werden die DTAPeaks aufgrund des Polarisationseffektes der Kationen der äußeren Sphäre und des nukleophilen Charakters der Liganden diskutiert. Die Ergebnisse werden mit jenen der thermischen Zersetzung der analogen Salze des H₃[Cr(NCS)₆] Komplexes verglichen.

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A. H[Cr(NCS)₄ ()₂], — , , - , «» . M[Cr(NCS)₄ ()₂], -, Ag, Tl, 1/2 Cd, 1/2Pb 1/3 Bi, « » — , . . Cr(NCS)₃, . , . , - . H₃[Cr(NCS)₆].

     

Ammoxidation of 3- and 4-picolines over V2O5?SnO2/γ?Al2O3 catalyst

The ammoxidation of 3- and 4-picolines has been studied over V₂O₅–SnO₂/–Al₂O₃ catalysts prepared by surface impregnation technique. Best results were obtained for the generation of cyanopyridines in the temperature range 400–450°C and sub-stoichiometric value with respect to O₂. Catalysts that were calcined above 700°C showed no activity.

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3- 4- V₂O₅–SnO₂/–Al₂O₃, . 400–450°C O₂. , 700 K, .

     

On the pattern of hydrogenolysis of hexane isomers over four Group VIIIB metals

The hydrogenolysis patterns of five hexane isomers have been compared over Rh, Pd, Ir and Pt. The selectivity of rupture of various C–C bond types is different for various metals. The fingerprint-like patterns are, as a rule, similar to those reported in the literature, their correlation with the position of the metal in the periodic system is pointed out.

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5- Rh, Pd, Ir Pt. C–C , . .

     

Temperature dependence of CO insertion on S-, Ag-, and Cu-promoted Rh/SiO2 catalysts

The addition of sulfur and silver to Rh/SiO₂ inhibits hydrogenation of C₂H₄, but promotes CO insertion and extends the linearity of Arrhenius curves for CO insertion above 543 K.

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Rh/SiO₂ C₂H₄, CO CO 543 .

     

On the dioximine complexes of transition metals. LXXVIII1 TG and DTA study of the thermal decomposition of some complexes M[Co(DH)2XY] and [Co(DH)2(H2O)X]

18 monobasic complex acids of the type H[Co(DH)₂XY] (X, Y=Cl, Br, I, NO₂, N₃, NCS, NCSe, CN), or their alkalimetal and ammonium salts, and 5 aquo-acido-nonelectrolytes, [Co(DH)₂(H₂O)X] (DH=deprotonated dimethylglyoxime), were obtained and their thermal decompositions were studied by means of TG and DTA. The thermolysis processes are discussed. Kinetic parameters have been derived for several decomposition stages and are discussed in terms of the kinetic compensation effect.

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Zusammenfassung 18 monobasische Komplexsäuren des Typs H[Co(DH)₂XY] X, Y=Cl, Br, I, NO₂, N₃, NCS, NCSe, CN) oder deren Alkalimetall- und Ammoniumsalze und 5 Aquoacido-Nichtelektrolyte [Co(DH)₂(H₂O)X] (DH=deprotoniertes Dimethylglyoxim) wurden hergestellt. Die thermische Zersetzung dieser Verbindungen wurde mittels TG und DTA untersucht. Die Thermolyseprozesse werden diskutiert. Kinetische Parameter wurden für verschiedene Zersetzungsstufen ermittelt und werden in Verbindung mit dem kinetischen Kompensationseffekt diskutiert.

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H[Co(H)₂XY], H = , X, Y=Cl, Br, I, NO₂, N₃, NCS, NCSe, CN, , -- [Co(H)₂(H₂O)X]. . , .

     

Thermal decomposition of Y,La and light lanthanide complexes of hippuric acid

The conditions of thermal decomposition of the hippurates of Y, La and the light lanthanides from Ce(III) to Gd have been studied. When heated, the Y, Ce(III), Pr and Gd complexes decomposed in two stages, those of La, Sm and Eu in three stages, and that of Nd in four stages, the oxides finally being formed. The complexes lost crystallization water to form anhydrous (Nd) or hydrated salts, and then decomposed to oxides directly (Y, Ce(III), Pr(III) and Gd) or with intermediate formation of Ln₂O₂CO₃ (La, Nd, Sm and Eu). The temperature of oxide formation varied periodically with the ionic potential in the lanthanide series.

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Zusammenfassung Die Bedingungen der thermischen Zersetzung der Hippurate von Y, La und der leichten Lanthanide von Ce(III) bis Gd wurden untersucht. Beim Aufheizen zersetzen sich die Komplexe von Y, Ce(III), Pr und Gd in zwei Schritten, die von Sm und Eu in drei Schritten und der von Nd in vier Schritten zu den Oxiden. Die Komplexe verlieren Kristallwasser unter Bildung wasserfreier (Nd) oder hydratisierter Salze und zersetzen sich dann direkt (Y, Ce(III), Pr(III), Gd) oder über Ln₂O₂CO₃ (Ln, Nd, Sm, Eu) zu den Oxiden. Die Temperatur der Oxidbildung verändert sich periodisch mit abnehmenden Ionenpotential in der Lanthanidenreihe.

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, . , , , , — , — , . , , (, , ) Ln₂O₂CO₃ (, , ). .

     

Low-temperature adsorption of oxygen over platinum monocrystals

Adsorption of O₂ over Pt(111), (110) and (100) at 80 K has been studied by thermodesorption mass-spectrometry. The results indicate the formation of chemisorbed molecular oxygen species and the influence of the surface structure of platinum on the low-temperature adsorption of oxygen.

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- O₂ 80 Pt(111), (110), (100). . .