Quantum chemical study of the physical characteristics of the hydroxy groups of zeolites, III

The CNDO/2 method was applied to calculate the electronic structure of HY zeolite using cluster models Si₃AlO₁₂H ₈ ^– and Si₃AlO₁₂H₉. It has been shown that the probability of occurrence of H on a particular type of oxygen as well as the other physical characteristics of zeolite depend on both the type of oxygen and the position of the Al atom.

---

/2 , Si₃AlO₁₂H₈ Si₃AlO₁₂H₉. , , , Al.

     

Study of interaction between trimethyl-substituted silanes and silica surface

Interaction mechanism of (CH₃)₃SiX silanes (X=Br, I, N₃, NCS, NCO, CN, NCNSi(CH₃)₃ and SO₄Si(CH₃)₃ with dehydrated silica surface has been studied by IR spectroscopy. It has been established that (CH₃)₃SiCN, (CH₃)₃SiBr, (CH₃)₃SiI and [(CH₃)₃Si]₂SO₄ can be used as soft silylating agents for endcapping.

---

(CH₃)₃SiX (X=Br, I, N₃, NCS, NCO, CN, NCNSi(CH₃)₃, SO₄Si(CH₃)₃) -. , (CH₃)₃SiCN, (CH₃)₃SiBr, (CH₃)₃SiI [(CH₃)₃Si]₂SO₄ .

     

Acetylene adsorption on a clean iridium surface

The interaction of C₂H₂ with a polycrystalline iridium surface at 140 KT500 K has been studied by AES, XPS and UPS. A model of the bonding between C₂H₂ and Ir by the 1 orbitals of the hydrocarbon is proposed. The more pronounced energy splitting between the orbitals of acetylene during adsorption compared to that in the gas phase is ascribed to deformation of the acetylene molecule.

---

C₂H₂ . 140 KT500 K AES, XPS UPS. C₂H₂ Ir 1- . - , , .

     

Experimental study of the bifurcation diagram in the Belousov-Zhabotinskii reaction

In the citric acid-Mn²⁺–H₂SO₄–KBrO₃ system a hysteresis phenomenon in the switching on and off of the oscillations has been observed. The possible bifurcation diagrams of the system are discussed.

---

-Mn⁺²–H₂SO₄–KBrO₃ . .

     

Dispersity and reducibility of the molybdenum oxide phase in SiO2, SiO2?Al2O3 and γ-Al2O3 supported molybdena catalysts

XRD, isothermal and temperature-programmed reduction (TPR) experiments were carried out with SiO₂, SiO₂–Al₂O₃ and -Al₂O₃ supported catalysts. Molybdena is in a more disperse state on supports containing more alumina and it is more reducible on SiO₂–Al₂O₃ than on SiO₂ or -Al₂O₃. TPR curves were shown to reflect connections between reduction kinetics and dispersity.

---

-, , SiO₂, SiO₂–Al₂O₃ -Al₂O₃. , , SiO₂–Al₂O₃ SiO₂ -Al₂O₃. .

     

Some remarks on the periodical change of the stability constants of the lanthanide complexes

The correlations between the values of the lgK (K = stability constant of the lanthanide complex) and the reciprocal of the ionic radius 1/r or the sum of the ionization potentials ₁ ³ I for the lanthanide ions were reviewed for different ligands. A straight-line relationship (lgK – lgK)/lgK vs. (1/r – 1/r)/(1/r) or vs. ( ₁ ³ I – ₁ ³ I)/ ₁ ³ I was found within the tetrads La-Nd, Gd-Ho, and Er-Lu.

---

Bemerkungen zum periodischen Wechsel der Stabilitätskonstanten von Lanthaniden-Komplexen

Zusammenfassung Es wurde eine Übersicht der Korrelationen zwischen den Werten von logK (K = Stabilitätskonstante der Lanthanidenkomplexe) und den reziproken Ionenradien 1/r oder der Summe der Ionisierungspotentiale ₁ ³ I für die Lanthanidenionen für verschiedene Liganden gegeben. Dabei wurde eine lineare Korrelation für (lgK – lgK)/lgK gegen (1/r – 1/r)/(1/r) oder gegen ( ₁ ³ I – ₁ ³ I)/_1/3 I innerhalb der Tetraden La-Nd, Gd-Ho und Er-Lu aufgefunden.

     

Thermal studies on titanyl,zirconyl and hafnyl dithiocarbamato complexes

The dithiocarbamato complexes of titanyl(IV), zirconyl(IV) and hafnyl(IV), abbreviated as MO(S₂CNRR)₂·nH₂O(M=Ti, Zr or Hf,R=H,R=C₅H₉;R=H,R=C₇H₁₁,n=1 for Ti andn=2 for Zr and Hf), were prepared in aqueous medium and characterized by elemental analyses, magnetic susceptibility measurements and IR spectral studies. The thermal behaviour of these compounds under non-isothermal conditions was investigated by thermogravimetric, derivative thermogravimetric and differential scanning calorimctric techniques in nitrogen and oxygen atmospheres. The intermediates obtained at the end of various thermal decomposition steps were identified on the basis of analyses and IR spectral studies. Kinetic parameters, such as apparent activation energy and order of reaction, were determined by the graphical method of Coats and Redfern. The heats of reaction for the different decomposition steps were calculated from the DSC curves.

---

Zusammenfassung Die Thiocarbamato-Komplexe von Titanyl(IV), Zirkonyl(IV) und Hafnyl(IV) der allgemeinen Formel MO(S₂CNRR)₂·n H₂O (M=Ti, Zr oder Hf;R=H, R=C₅H₉;R=H, R=C₇H₁₁;n=1 für Ti undn=2 für Zr und Hf) wurden in wässrigem Medium hergestellt und durch Elementaranalyse, Messung der magnetischen Suszeptibilität und IR-Spektraluntersuchungen charakterisiert. Das thermische Verhalten dieser Verbindungen unter nicht-isothermen Bedingungen wurde durch TG, DTG und DSC in Stickstoff- und Sauerstoffatmosphäre untersucht. Die nach verschiedenen thermischen Zersetzungsschritten erhaltenen Zwischenprodukte wurden durch chemische Analyse und IR-Spektroskopie identifiziert. Kinetische Parameter, wie die scheinbare Aktivierungsenergie und die Reaktionsordnung, wurden nach der graphischen Methode von Coats und Redfern bestimmt. Für die einzelnen Zersetzungsschritte wurden die Reaktionswärmen aus den DSC-Kurven berechnet.

---

, . MO(S₂CNRR)₂·nH₂O (M=I, Zr, Hf,R=H,R ¹=C₅H₉, C₇H₁₁,n=1 I =2 ) , . , . , , . - . .

---

---

The authors are grateful to Dr. Shyam Kumar for helpful discussions.     

Effect of electronic interaction between metal and support, II. TPD, TPR and chemisorption studies on Ru/Al2O3?MgO catalysts

TPD, TPR and chemisorption were used to characterize Ru/Al₂O₃–MgO catalysts. It is suggested that the acidity of support may influence the properties of catalysts significantly.

---

, Ru/Al₂O₃–MgO. , .

     

Die Extraktion des Silbers als Tri-n-butylammonium-silbersaccharinat

Zusammenfassung Die Flüssig-flüssig-Extraktion des Silbers als Tri-n-butylammonium-silbersaccharinat mittels Methylenchlorid erlaubt die quantitative Trennung des Silbers von Blei, Wismut, Kupfer und Eisen bis zu jeweiligen Verhältnissen AgPb, Bi, Cu oder Fe=15000, 1100, 1230 oder 175 mit analytisch brauchbaren Ergebnissen. Das Silber wird aus der nichtwäßrigen Phase als AgCl oder Ag₂S gefällt und in diesen Formen zur Wägung gebracht.Dem Herrn Bundesminister für Atomkernenergie und Wasserwirtschaft sowie der Deutschen Forschungsgemeinschaft danken wir für Unterstützung.     

Kinetics and mechanism of hydrazine oxidation by oxygenated Co2(L-his)4O2 complex

The kinetics of Co₂ (L-his)₄O₂ reduction by hydrazine in aqueous solution has been studied and the rate constants, the energy and entropy of activation have been determined.

---

, , Co₂ (L-)₄O₂ .

     

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.

---

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.

---

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

     

Application of sol-gel process to H-zeolite synthesis over amorphous aluminosilicate materials

The impregnation preparation of H-zeolite over amorphous aluminosilicate solids (cracking catalysts) is compared with new synthesis procedures based on sol-gel process. The characterization results show that the H-zeolite reacts with the intermediates of the amorphous aluminosilicate.

---

H- ( ) , -. , H- .

     

IR spectroscopic studies of adiponitrile and ammonia adsorption over Ti?Sb?O catalyst

Rate constants for the aminolysis of o-(2,4-dinitrophenyl) cyclopentanone oxime with several primary alkylamines, C₂H₅NH₂–C₆H₁₃NH₂ and one secondary arylamine, purrolidine, in 11 water-acetonitrile are reported. With primary amines, base catalysis is absent, while with pyrrolidine saturation catalysis has been observed. Reduction in size of nonconjugated oxime moiety (leaving group), drastically decreases the rates. Thermodynamic parameters for these reactions have also been calculated.

---

O-(2,4-) (C₂H₅NH₂–C₆H₁₃NH₂) , , : =11. , . ( ) . .

     

Quantum chemical calculations on the catalytic dehydration of 2-propanol

The charge on atoms and the bond strengths in CH₃CHOHCH₃, CH₃ CH₃, CH₃CHOHCH ₂ ^– , CH₃ CH ₂ ^– and CH₃ CH₃...O(H)CH(CH₃)₂ have been calculated by the CNDO/2 method. The results are in agreement with published experimental observations on catalytic dehydration. A modified mechanism of anti-elimination on solid catalysts is proposed.

---

CH₃CHOHCH₃, CH₃ CH₃, CH₃CHOHCH ₂ ^– , CH₃ CH ₂ ^– CH₃ CH₃...O(H)CH(CH₃)₂, CNDO/2. . .

     

Effect of free phosphine on the reactivity of phosphine-containing rhodium(I) complexes

The photolysis products of SO₂-pentane-NO mixtures are N₂O, H₂O and a compound designated as RNO. Kinetic data obtained by OC method confirm the previously proposed scheme of photolysis. Also studied was the photolysis of SO₂, NO and cyclohexane mixtures. From comparison of spectral characteristics of RNO and its analog 2-methyl-2-nitrosopropane, the probable structure of RNO is suggested.

---

SO₂--NO N₂O, H₂O , RNO. , , . SO₂ NO . RNO 2--2- RNO.

     

Uncatalyzed and catalyzed bromate driven oscillations in salicylic and 5-sulfosalicylic acid

Kinetics of the reactions of WCl₆ with Ph₄Sn, Ph₃SnCl and Ph₂SnCl₂ have been studied by UV-VIS spectroscopy. Approximate values of the corresponding rate constants in benzene have been obtained.

---

WCl₆ Ph₄Sn, Ph₃SnCl Ph₂SnCl₂, , - . .

     

Phthalocyaninartige Bor-Komplexe

Zusammenfassung Aus Halogenboranen und Organohalogenboranen (RBX ₂R=C₆H₅, Cl, Br;X=F, Cl, Br) sowie aus Organoboranen oder Thioboranen entstehen mit Phthalodinitril Triisoindolo-[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8,9a,9b]-hexaazaboraphenalene von denen die B–Cl- und B–F-Verbindungen näher charakterisiert werden.Dekaboran(14), Diboran(6) oder Boranaddukte von Stickstoffbasen liefern hingegen mit Phthalodinitril metallfreies Phthalocyanin.

---

Triisoindolo[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8,9a,9b]-hexa-azaboraphenalene

Triisoindolo[1,2,3-cd1,2,3-gh1,2,3-kl][2,3a,5,6a,8, 9a,9b]-hexaazaboraphenalenes are obtained from the reactions of haloboranes and organohaloboranes (RBX ₂R=C₆H₅, Cl, Br;X=F, Cl, Br) as well as from organoboranes or thioboranes with phthalodinitrile. The B–Cl and B–F compound have been characterized by analyses, i.r.-, u.v.- and mass-spectrometry.Diborane(6), dekaborane(14) and amine-boranes, however, upon reaction with phthalodinitrile lead to high yields of metal free phthalocyanine.

---

---

Herrn Prof. Dr.M. Pailer zum 60. Geburtstag gewidmet.     

Infrared studies of CO2(CO)8 adsorption on zeolites Y

Co₂(CO)₈ sublimed onto the surface of HY, CeY, CoY and two dealuminated forms of NaY zeolite is converted at room temperature to Co₄(CO)₁₂ and other surfacebound cobalt carbonyl species. The reaction proceeds in a different way on each of the above zeolites, depending also on their pretreatment.

---

Co₂(CO)₈, HY, CeY, CoY NaY, Co₄(CO)₁₂ - . - .

     

Formation of methyl platinum complex in the reaction of methane with chloroplatinic acid

The¹HNMR method and chemical analysis indicate that a complex of Pt(IV) containing a CH₃–Pt fragment is formed in the reaction of H₂PtCl₆+H₂PtCl₄ with methane at 120 °C in aqueous CF₃CO₂H. The complex was isolated from the solution as an adduct of Ph₃P.

---

, H₂PtCl₆ H₂PtCl₄ CF₃COOH 120°C (IV), Pt–CH₃. Ph₃P , .

     

A model of reaction front propagation in crystals

A spatio-temporal model of anisotropic propagation of the dehydration front in Na₃P₃O₉ · 6H₂O single-crystals is discussed. It is based on the assumption that dehydration proceeds as a periodic displacement of the reaction front from one reacting elementary block to another, and that experimentally fixed dehydration patterns are composed of a multitude of elementary patterns having the same shape. The model can be applied to other crystals.

---

Zusammenfassung Ein Zeit- und Raummodell der anisotropischen Fortschreitung der Dehydratationsgrenzfläche in Na₃P₃O₉ · 6H₂O Einkristallen wird diskutiert. Das Modell ist auf einer Annahme begründet, dass die Wasserabspaltung als eine periodische Propagation der Reaktionsgrenzfläche von einem reagierendem Elementarblock zu anderem verläuft und dass die experimentell fixierte Entwässerungsfiguren aus einer Menge von Elementarfiguren von identischer Form zusammengestellt sind. Das Modell kann auf andere Kristallen verbreitet werden.

---

- Na₃P₃O₉· 6₂. , , . .