Bestimmungen von Chlorkohlenwasserstoffen in Siliciumhalogeniden mit Hilfe von zwei gas-chromatographischen Verfahren und deren methodischer Vergleich

Zusammenfassung Zur Bestimmung der Chlorkohlenwasserstoffe trans-Dichlorethen, cis-Dichlorethen und 1,1,1-Trichlorethan wurden 2 gas-chromatographische Verfahren entwickelt. Bei Verfahren I werden die Verunreinigungen nach Abtrennung der Matrix SiHCl₃ durch KHF₂ mittels Dampfraumtechnik angereichert und gas-chromatographisch mit einem Flammenionisationsdetektor bestimmt. Bei Verfahren II werden die Verbindungen direkt gas-chromatographisch erfaßt, wobei ein Massenspektrometer mit fester Masseneinstellung als Detektor eingesetzt wird. Die Nachweisgrenze liegt bei ca. 0,1 Gew.-ppm für diese Verbindungen bei beiden Verfahren. Ein Vergleich beider Methoden wurde durchgeführt.

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Determination of halogenated hydrocarbons in silicon halides with two gas-chromatographic methods and a comparison of these analyses

Summary Two gas-chromatographic methods are developed for the determination of the chlorinated hydrocarbons trans-dichloroethene, cis-dichloroethene and 1,1,1-trichloroethane. In method I the impurities are enriched after separation of SiHCl₃ by KHF₂ with the aid of headspace technique and are determined by gas-chromatography with a flame-ionisation detector. In method II the compounds are analyzed directly by gas-chromatography using a mass spectrometer with focussed peaks as detector. The detection limit was found to be about 0.1 ppm (wt.) of the compounds for these two methods. Measurements of some investigated samples are compared.

     

Nouvelles syntheses de Me2SiCl2 et Me3SiCl

Partial reduction of MeSiCl₃ and Me₂SiCl₂ using CaH₂ or (TiH₂)_n at high temperature (300°C) leads to MeSiHCl₂ and Me₂SiHCl, respectively, in good yields but in low proportion. In the presence of AlCl₃ as catalyst the reaction affords Me₂SiCl₂ and Me₃SiCl, in yields higher than those previously observed in the absence of a reducing agent. These redistribution reactions involve MeSiHCl₂ and Me₂SiHCl as intermediates. Consequently Me₂SiHCl with or without Me₂SiCl₂ and Alcl₃ deposited on carbon black as catalyst can undergo disproportionation to give Me₃SiCl.     

Metal-containing initiator systems. V. Radical and cationic polymerizations with initiator systems of reduced nickel and chlorosilanes

The polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH₃)_nSiCl_4?n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl₄ > CH₃SiCl₃ > (CH₃)₂SiCl₂ > (CH₃)₃SiCl ? 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH₃)₃SiCl > (CH₃)₂SiCl₂ > CH₃SiCl₃ ? SiCl₄. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed.     

Bildung siliciumorganischer Verbindungen. XXXIX. Teilchlorierte Carbosilane

1. Photochlorination in CCl₄ of the Si-chlorinated carbosilanes (Cl₃Si? CH₂)₂SiCl₂ and (Cl₂Si? CH₂)₃ leads to totally chlorinated compounds, e. g. (Cl₃Si? CCl₂)₂SiCl₂. After chlorination has started at one CH₂ group, formation of a CCl₂ group is preferred before another CH₂ group is involved into the reaction. Thus preparation of compounds a, b, c is possible. Cl₃Si? CCl₂? SiCl₂? CH₂? SiCl₃ (a) for (b) and (c) (see “Inhaltsübersicht”). SO₂Cl₂ (benzoyl peroxide) as chlorinating agent reacts more slowly, and opens an access to carbosilanes containing CHCl groups such as (d), Cl₃Si-CHCl? SiCl₂? CH₂? SiCl₃ (e). Reactions of compounds (a) to (d) with LiAlH₄ yields carbosilanes with SiH groups, and partially chlorinated C atoms. 2. By the high reactivity of Si? CCl₂? Si groups an exchange of Cl atoms of CCl groups in perchlorinated carbosilanes is possible for H atoms of Si? H groups in perhydrogenated carbosilanes, thus allowing the preparation of compounds containing CHCl and SiHCl groups, e. g. according to Gl.(1) (Inhaltsübersicht). Further reactions, formulated as the last equations in Inhaltsübersicht, are reported as well as the rearrangement of H₃Si? CHCl? SiH₃.     

Gas-chromatographische Analyse von Chlorkohlenwasserstoffen in Siliciumhalogenverbindungen

Zusammenfassung Die Chlorkohlenwasserstoffe trans-Dichloräthen, 1,1-Dichloräthan, 1,1,1-Trichloräthan und Trichloräthylen werden nach Abtrennung des SiCl₄ mittels Dampfraumtechnik angereichert und gaschromatographisch analysiert. Die Nachweisgrenze liegt bei ca. 1 Gew.-ppm für diese Verbindungen.

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Gas-chromatographic analysis of halogenated hydrocarbons in silicon halides

Summary The chlorinated hydrocarbons trans-dichloroethene, 1,1-dichloroethane, 1,1,1-trichloroethane and trichloroethylene are enriched after separation of tetrachlorosilane with the aid of head-space technique and are determined by gas-chromatography. The detection limit is found to be about 1 ppm (wt.) of these compounds.

     

Ozonolytic determination of double-bond positions in olefins by gas chromatography

Summary Olefinic compounds are reacted with ozone in CCl₄/CH₃OH solution, yielding specific cleavage products, from which the original position of the double bond can be deduced. By reduction with dimethylsulfide the resulting methoxyhydroperoxides are converted into aldehydes and ketones, which are determined by temperature-programmed gas chromatography on silicone columns. The lower compounds (C₁-C₁₀) are analyzed as dinitrophenylhydrazones, the less volatile higher ones as such. 100% yields were obtained for monoolefins of different structures and chain lengths (up to C₃₀).

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Ozonolytische Bestimmung von Doppelbindungen in Olefinen durch Gas-Chromatographie

Zusammenfassung Die Olefine werden in CCl₄/CH₃OH-Lösung mit Ozon behandelt, wodurch spezifische Spaltprodukte entstehen, aus denen man die ursprüngliche Lage der Doppelbindung ableiten kann. Die entstandenen Methoxyhydroperoxide werden durch Reduktion mit Dimethylsulfid zu Aldehyden und Ketonen umgesetzt, die durch temperaturprogrammierte Gas-Chromatographie an Siliconsäulen analysiert werden. Die niedrigeren (C₁-C₁₀) Verbindungen werden als Dinitrophenylhydrazone bestimmt, die weniger flüchtigen höheren als solche. Für aliphatische Monoolefine verschiedener Struktur und Kettenlänge (bis C₃₀) wurden 100%ige Ausbeuten erhalten.

Lecture presented at Euroanalysis I Conference, 28. 8.–1. 9. 1972 in Heidelberg, Germany.     

Pressure Dependence of Rate Coefficients for Formation and Dissociation of Pentachlorodisilane and Related Chemical Activation Reactions

Four entrance channels to the pentachlorodisilane (Si₂HCl₅) potential energy well, namely, SiCl₂ + SiHCl₃, SiCl₄ + SiHCl, Cl₃SiSiCl + HCl, and SiCl₃ + SiHCl₂, were analyzed in detail through transition state theory, Rice–Ramsperger–Kassel–Marcus (RRKM) theory, and solution of the multichannel master equation. The stationary points in the potential energy surface were optimized, and their vibrational frequencies and rotational constants calculated at the (U)B3LYP/6–31+G(d,p) level of theory; the (U)CCSD(T)/aug‐cc‐pVTZ level was then used for accurate estimation of activation energies. The pressure and temperature dependence of the rate coefficients of the channels related to Si₂HCl₅ stabilization/dissociation was determined along a wide range of conditions, for the first time. All channels showed strong pressure dependence in the four cases, at least at low‐to‐moderate pressure conditions. Each entrance channel leads to the formation of different products under different conditions, and the mechanism was analyzed in detail. The results indicated that at atmospheric pressure the reactions are in the falloff region, and therefore do not support the adoption of high‐pressure limit rate coefficients in reaction models designed for simulation of systems at atmospheric or subatmospheric pressure conditions.     

Bildung siliciumorganischer Verbindungen. XXXVII1,3,5,7-Tetrasila-adamantane aus der Pyrolyse des (CH3)3SiCl und Auftrennung des Pyrolysegemisches

Further separation of the pyrolysis products of (CH₃)₃SiCl can be achieved by reaction with LiAlH₄/LiH (transfer of SiCl to SiH groups). By means of adsorptions chromatography a separation is obtained into 4 groups of components. By application of gel chromatography (sephadex LH 20) separation is improved, thus fractions of carbosilanes are found with average molecular weights between 5000 and 200. A given mixture of the compounds [5], [9], [10] has been separated by means of gel chromatography so that pure compounds were obtained. The mixture of the 1,3,5,7-Tetrasila-adamantanes, which are formed in the pyrolysis of (CH₃)₃SiCl, is separated by gel chromatography (efficiency control of separation is performed by NMR and mass spectrography of the different fractions), a concentration of some compounds is obtained, some of them are isolated purely by further operations. The ratio of the compounds [1], [2], [3], [4], found in the pyrolysis products, is 170:26:3:1. Derivatives are formed with SiH, SiCl, and SiCH₃ groups by complete or respectively partial hydrogenation. Comparing the values of the chemical shift of the CH₃-protones [measured in τ) a linear decrease is found in the compounds [9], [4], [3], [2].     

Preparation of bis-(γ-trifluoropropyl)dichloro

Summary It was shown that (CF₃CH₂CH₂)₂SiCl₂, along with Cl₃SiCH₂CH₂CF₃ and CH₃Si(Cl)₂CH₂CH₂CF₃ may easily be prepared without danger by the addition of H₂SiCl₂ and HSiCl₃ or CH₂SiHCl₂ in the presence of platinohydrochloric acid.     

Reactions of organylhalosilanes with 1,1,3,3-tetra- and hexamethyldisilazane

Organylchlorosilanes, and also SiCl₄, decompose 1,1,3,3-tetra- and hexamethyl-disilazanes with formation of hitherto unknown organylchlorosilazanes of general formulas R_4–nSiCl_n–1NHSiH(CH₃)₂ and R_4–nSiCl_n–1NHSi(CH₃)₃ (n=2–4) in yields of 54–98%. The IR and mass spectra of the prepared compounds were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1159–1162, May, 1991.     

Dendrimers with 1, 3, 5‐Trisilacyclohexane as Core Unit

1, 1, 3, 3, 5, 5‐Hexavinyl‐1, 3, 5‐trisilacylohexane [Si(CH=CH₂)₂CH₂]₃ was synthesized and hydrosilylated with trichlorosilane to afford the first generation of a dendrimer. Conversion of this molecule with 18 Si–Cl functions on its surface with an excess of vinylmagnesium bromide yielded the 18‐fold vinylated dendrimer. The new compounds were identified by elemental analyses, multi‐nuclear NMR spectroscopy, and mass spectrometry. Crystal structures were obtained for [Si(CH=CH₂)₂CH₂]₃ and [Si(CH₂–CH₂SiCl₃)₂CH₂]₃.     

1,1-Diethynylsilacycloalkanes and Propellanes Based Thereon

Previously unknown 1,1-diethylnylsilacycloalkanes (CH₂)4nSi(C& = CH)₂ (n = 3, 4) were prepared by the reaction of HC& = CMgBr with 1,1-dichlorosilacycloalkanes (CH₂)4nSiCl₂ (n = 3, 4). The reaction of (CH₂)₄Si(C& = CMgBr)₂ with (CH2)4SiCl2 in THF under conditions of high dilution gives cyclo(tetramethylene)- silethynes [(CH2)4SiC& = C]4 with an admixture of cyclodi(tetramethylene)silethyne [(CH2)4SiC& = C]2. The re- action of Me2Si(C& = CSiMe2C& = CMgBr)2 with (CH2)4SiCl2 was used to prepare 1,1,4,4,7,7-hexamethyl-10,10- tetramethylene-1,4,4,10-tetrasilacyclododeca-2,5,8,11-tetrayne.     

Reaktionen der Siliciumtetrahalogenide mit 2,2′-Dipyridyl und mit 1,10-Phenanthrolin

Zusammenfassung In den Systemen Siliciumtetrahalogenid/2,2-Dipyridyl und Siliciumtetrahalogenid/1,10-Phenanthrolin bilden sich unter Wärmeentwicklung weiße bis leicht getönte röntgenkristalline Additionsverbindungen des Typs Hlg₄Si(dipy) bzw. Hlg₄Si(phen) mit SiHlg₄=SiCl₄, SiHCl₃ und SiBr₄. Mit SiJ₄ waren analog die gelben Verbindungen J₄Si(dipy) und J₄Si(phen)₂ zu erhalten. Methylchlorsilane reagieren mit den beiden Heterocyclen nicht. Pyrazin setzte sich nur mit SiJ₄ um, offensichtlich zu gelbem J₄Si(pyz)₄.

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The reaction of silicon tetrahalides (SiCl₄, SiHCl₃, SiBr₄) with 2.2-dipyridyl and 1.10-phenanthroline respectively results in white, or only slightly coloured crystalline addition compounds of the composition X₄Si(dipy) and X₄Si(phen), whereas SiI₄ formed the yellow compounds I₄Si(dipy) and I₄Si(phen)₂ and, with pyrazine, the yellow I₄Si(pyz)₄. Methylchlorosilanes did not react.

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Ausführliche Darstellung eines Diskussionsvortrages beim 1. Dresdener Symposium für Siliciumchemie, Mai 1958. Vgl. hierzu.

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65. Mitt.:U. Wannagat, K. Hensen undP. Petesch, Mh. Chem.98, 1407 (1967).

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Zugleich 5. Mitt. über Verbindungen von Nichtmetallhalogeniden mit Pyridin und seinen Homologen; 4. Mitt. siehe.

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Mit Auszügen aus der DiplomarbeitP. Petesch, T. H. Aachen 1958, und den DissertationenF. Vielberg, T. H. Aachen 1956, sowieK. Hensen, T. H. Aachen 1962.     

Amperostatische Coulometrie von Ferrocen und seinen Derivaten in Acetonitril

Zusammenfassung Zur amperostatischen Coulometrie von Ferrocenen wird Cu(I)BF₄ als Hilfsstoff zugegeben, da Ferrocen sich leicht durch Cu(II)(BF₄)₂ oxidieren läßt. Der Verlauf der Titration wird biamperometrisch verfolgt. Die Proben enthalten nur wenige Milligramme der betreffenden Verbindungen. Die Resultate sind zufriedenstellend.

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Amperostatic coulometry of ferrocene and its derivatives in acetonitrile

Summary Cu(I)BF₄ was added as an auxiliary substance as Cu(II) (BF₄)₂ can bring about the oxidation of ferrocene. The advancement of the titration was followed by means of biamperometry. The samples contained a few milligrams of the compounds concerned and the results were satisfactory.

     

Vergleich der Siliciumtetrahalogenid-addukte mit den Hydrogenhalogeniden des 2.2′-Dipyridyls und des 1.10-Phenanthrolins

Zusammenfassung Die folgenden Hydrogenhalogenide des Pyridins (=py) und einiger verwandter Verbindungen (dipy=2.2-Dipyridyl,phen=1.10-Phenanthrolin) wiepy·HCl,py·HBr,py·HJ,dipy·2 HCl.dipy·HJ,dipy·2 HJ,dipy·2 HJ·2 H₂O,phen·HCl·H₂O,phen·3 HCl,phen·1/2 HJ,phen·HJ,phen·2 HJ,phen·HJ·2 H₂O, Chinolin·HJ, -Picolin·HJ, Collidin·HJ, Acridin·HJ, werden beschrieben, und ihreDebye-Scherrer-Diagramme mit denen der Siliciumtetrahalogenidaddukte der genannten Heterocyclen, SiCl₄ py ₂, SiHCl₃ py ₂, SiBr₄ py ₂, SiJ₄ py ₄, SiCl₂J₂ py ₄, SiCl₄ dipy, SiHCl₃ dipy, SiBr₄ dipy, SiJ₄ dipy, SiCl₄ phen, SiHCl₃ phen, SiBr₄ phen und SiJ₄(phen)₂ verglichen.

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The following hydrogen halides of pyridine (=py) and some similar compounds (dipy=2.2-bipyridyl,phen=1.10-phenanthroline)py·HCl,py·HBr,py·HI,dipy·2HCl,dipy·HI,dipy·2HI,dipy·2HI·2H₂O,phen·HCl·H₂O,phen·3HCl,phen·1/2HI,phen·HI,phen·2HI,phen·HI·2H₂O, quinoline·HI, -picoline·HI, collidine·HI, acridine·HI are described and compared in their X-ray-diagrams with the addition compounds of silicon tetrahalides SiCl₄ py ₂, SiHCl₃ py ₂, SiBr₄ py ₂, SiI₄ py ₄, SiCl₂I₂ py ₄, SiCl₄ dipy, SiHCl₃ dipy, SiBr₄ dipy, SiI₄ dipy, SiCl₄ phen, SiHCl₃ phen, SiBr₄ phen, and SiI₄(phen)₂.

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Mit 4 Abbildungen

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5. Mitt.:U. Wannagat, K. Hensen, P. Petesch undF. Vielberg, Mh. Chem.98, 1415 (1967).

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Mit Auszügen aus der DiplomarbeitP. Petesch, Techn. Hochsch. Aachen 1958, und der DissertationK. Hensen, Techn. Hochsch. Aachen 1962     

CsCu4S3 und CsCu3S2: Sulfide mit tetraedrisch und linear koordiniertem Kupfer

Thermodynamics of the System Si? Cl? H By static and dynamic methods the equilibria 4SiHCl₃,g = 3SiHCl₄,g + Si,s + 2H₂,g (1) between 800 and 1140 K and SiCl₄,g + H₂,g = SiHCl₃,g + HCl,g (2) between 1170 and 1450 K were investigated. The expression for the temperature dependence of the equilibria were found to be lg Kp [Torr] = (5.688–1520/T) ± 0.32 (1) and lg Kp = (1.38/3250/T) ± 0.16 (2). The values measured for reaction pressures and equilibrium constants lead to the conclusion, that the difference of enthalpies of formation of SiCl₄ and SiHCl₃ found in literature is nessecarily to be corrected by 5–6 kcal/mole. With ΔH(SiCl₄,g) = ?157.1 kcal/mole the equilibrium measurements lead to the enthalpy of formation for SiHCl₃,g of ΔH(SiHCl₃,g) = ?118.2 kcal/mole.     

Extraktion von Selen(IV) mit unges?ttigten Kohlenwasserstoffen aus salzsauren L?sungen

Zusammenfassung Die Extraktion von Selen(IV)-organischen Verbindungen mit inerten organischen Lösungsmitteln im salzsauren Medium wird untersucht. Verwendet wurden 32 aliphatische und cyclische ungesättigte Kohlenwasserstoffe unterschiedlicher Struktur. Verbindungen von Typ (RCHClCH₂)₂SeCl₂-R=Kohlenwasserstoffrest —wurden extrahiert. Zur Festlegung der günstigsten äußeren Bedingungen für eine hochselektive Extraktion wurden die Geschwindigkeitskonstanten der einzelnen ungesättigten Kohlenwasserstoffe mit Selen(IV) berechnet. Als Lö-sungsmittel sind Chloroform und Dichloräthan besonders geeignet. Die Zusammensetzung und Konformation der Verbindungen wurden mit Hilfe der Elementaranalyse, ¹H-NMR-, IR- und massenspektroskopischen Methode bestätigt.

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Extraction of selenium(IV) by unsaturated hydrocarbons from hydrochloric acid solutionAnalytical application and structural analysis

Summary The extraction of selenium(IV)-organic compounds by inert organic solvents from hydrochloric acid media is investigated. 32 aliphatic and cyclic unsaturated hydrocarbons of different structures are used. Compounds of the type (RCHClCH₂)₂SeCl₂ -R=hydrocarbon group —are extracted. The rate constants of the single unsaturated hydrocarbons with selenium(IV) are calculated to define the most favourable conditions of a highly selective extraction. As solvents chloroform and dichlorethane are especially suitable. The composition and conformation of the compounds are confirmed by elemental analysis, ¹H-NMR, IR- and mass spectroscopy.

Für die Gewährung eines Stipendiums (L.F.) danken wir der Alexander von Humboldt-Stiftung und dem Fonds der Chemischen Industrie für Sachmittel.     

Synthesen und Charakteristika von Heterobimetallorganika des Siliciums mit dem 2‐(Dimethylaminomethyl)ferrocenyl‐Liganden FcN (η5‐C5H5)Fe[η5‐C5H3(CH2NMe2)]—

Syntheses and characteristics of the heterobimetalorganics of the silicon with the 2‐(dimethylaminomethyl)ferrocenyl ligand FcN (η⁵‐C₅H₅)Fe[η⁵‐C₅H₃(CH₂NMe₂)]^— The heterobimetallic lithiumorganyl [2‐(dimethylaminomethyl)ferrocenyl] lithium, LiFcN, reacts with silicon(IV)‐chlorid, SiCl₄, under the formation of heterobimetallic silicon(IV) organyl [(FcN)₃SiCl] ( 1 ). The heterobimetallic organosilanol [(FcN)₃SiOH] ( 2 ) is formed at hydrolysis of 1 . A detailed characterization of the defined compounds 1 and 2 was carried out by NMR‐ rsp. mass‐spectrometry and by crystal X‐ray analysis of 2 .     

Photoelectron spectroscopic investigation of phenyl isocyanato silanes

Summary The HeI photoelectron spectra of compounds C₆H₅(CH₃) _n Si(NCO)_3–n were recorded and analysed using semiempirical AM1 quantum chemical calculations. The interaction between phenyl and pseudohalide groups is minimal. The splitting of bands originated from pseudohalide groups is not sensitive to the Si-N-C bond angle.

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Photoelektronenspektroskopische Untersuchungen von Phenyl-isocyanato-silanen

Zusammenfassung Es wurden die Photoelektronenspektren von Verbindungen C₆H₅(CH₃) _n Si(NCO)_3-n aufgenommen und die Spektren mit der Hilfe von semiempirischen quantenchemischen AM1 Rechnungen ausgewertet. Die Wechselwirkung zwischen den Phenyl- und Pseudohalogenidgruppen erwiesen sich als minimal. Die Aufspaltung der infolge der Pseudohalogenidgruppe entstandenen Bänder ist gegen den Bindungswinkel von Si-N-C unempfindlich.