Reactions of some sterically-hindered organosilicon hydrides and iodides with halogens

The reaction of TsiSiMe₂H (I) (Tsi = (Me₃Si)₃C) with I₂ or with a molar equivalent of ICl gives the iodide TsiSiMe₂I (II) in hydroxylic media (MeOH, CH₃CO₂H, CF₃CO₂H) as it does in CCl₄. The reaction with I₂ is very fast in CF₃CO₂H, but in MeOH is only about as fast as in CCl₄. The iodide II reacts with ICl in MeOH to give a mixture of TsiSiMe₂OMe (III) and TsiSiMe₂Cl (IV), but the reaction is markedly slower than that in CCl₄ (in which IV is formed). The hydride I also reacts with INO₃ in MeOH to give II, and the latter reacts with INO₃ to give III. The reactions of TsiSiPh₂H (V) and TsiSiPh₂I (VI) with ICl in MeOH are markedly slower than those of I and II; even with one equivalent of ICl in MeOH, V gives a mixture of VI and the (rearranged) methoxide (Me₃Si)₂C(SiPh₂Me)(SiMe₂OMe) (VII). Reaction of VI with ICl in MeOH gives VII and the rearranged chloride (Me₃Si)₂C(SiPh₂Me)(SiMe₂Cl). The formation of methoxides in the reactions of the iodides II and VI with ICl in MeOH, and the rearrangements observed in the case of VI, are consistent with a mechanism involving an intermediate silicocation. Other mechanistic aspects are discussed.     

The reaction of MgCl2·4H2O with CCl2F2

A new reaction of MgCl₂·4H₂O with CCl₂F₂ is investigated by DTA and TG from room temperature to 350 °C. It is observed that MgF₂ was obtained between 252 and 350 °C, Below the temperature, MgCl₂·4H₂O dehydrates and hydrolyzes to MgCl₂ and Mg(OH)Cl, which are the real reactants of the reaction with CCl₂F₂. The formation of MgF₂ is ascribed to the reaction of MgCl₂ and Mg(OH)Cl with HF, which forms by decomposition of CCl₂F₂ with the taking part in of H₂O released from dehydration of hydrated magnesium chloride on the surface of MgCl₂ and Mg(OH)Cl, which catalyzes the decomposition of CCl₂F₂ in this case. Consequently, the reactions are tested in the fluid-bed condition. It is found that MgF₂ formed at temperatures down to 200 °C in a fluid-bed reactor. This reaction may be used as a method of disposing of the environmentally sensitive CCl₂F₂ (rather than release into the atmosphere). It is also a method for the preparation of MgF₂.     

Polymerization of Methyl Methacrylate by Charge-Transfer Mechanism with Amines and Carbon Tetrachloride

The charge-transfer complex formed between an amine and carbon tetrachloride can initiate the polymerization of vinyl monomers in a nonaqueous solvent such as dimethylsulfoxide. Here we use cyclopentylamine (CPA) and heptylamine (HA) as the donor compounds for charge-transfer initiation of the polymerization of methl methacrylate (MMA). The rate of polymerization R_p = k[MMA]¹ [amine]^0.5 [CCl₄]^0.5 when [CCl₄] [amine] ≤ 1; when [CCl₄] [amine] < 1, R_p becomes independent of [CCl₄] and R_p = k[MMA]^1.5 [amine]^0.5. The average constant at 60°C for the polymerization of MMA in terms of monomer were (1.66 ± 0.03) × 10^?5 and (1.46 ± 0.04) × 10^?5 s^?1 with CPA and HA, respectively, when [CCl₄] [amine] ≤ 1, and (1.16 ± 0.04) × 10^?5 and (1.39 ± 0.08) × 10^?1 L/mol·s when [CCl₄]/[amine] < 1.     

Synthesis and reactions of [tris(trimethylsilyl)methyl]ethyl dichlorosilane

The crowded dichlorosilane TsiSiEtCl₂, (1), (Tsi = (Me₃Si)₃C) was prepared from the reaction between EtSiCl₃ and TsiLi, then it was reduced with LiAlH₄ to give TsiSiEtH₂, (2). The hydride (2) was then treated with two equivalents of ICl/CCl₄ or Br₂/CCl₄ to produce TsiSiEtI₂, (3), and TsiSiEtBr₂, (4), respectively. The reaction of compound (2) with one equivalent of ICl/CCl₄ gives TsiSiEtHI, (5). This product reacted with H₂O/dioxane in the presence of AgClO₄ or with dry MeOH to produce TsiSiEtHOH, (6), and TsiSiEtHOMe, (7), respectively. The compound (3) reacted with H₂O in DMSO/CH₃CN to give TsiSiEt(OH)₂, (8), and the compound TsiSiEtIOMe, (9), was prepared from the reaction of the compound (7) with ICl/CCl₄. When the dichloride (1) was treated with NaOMe/MeOH it gave (Me₃Si)₂CHSiEt(OMe)₂. It is suggested that the reaction proceeds through an elimination-addition mechanism. The dichloride (1) was also treated with KSCN, NaN₃ or NaOCN in CH₃CN to give S_N2 substitution products. All the new products were characterized by FTIR, ¹H NMR, and ¹³C NMR spectroscopy, mass spectrometry and elemental analysis.     

Solvent extraction behaviour of iodine and bromine in aqueous-organic systems,analogy with radioactive decay

The extraction of iodine and bromine under various conditions from their saturated aqueous solutions by CCl₄, C₆H₆ and o-xylene has been studied. The data obtained from the experiments carried out at various temperatures, for H₂O(I₂)−CCl₄ and H₂O(I₂)−C₆H₆ systems, exhibit an Arrhenius behaviour. The overall activation energy calculated for the extraction in the H₂O(I₂)−CCl₄ system, 650±50 cal·mol⁻¹ is lower than that of H₂O(I₂)−C₆H₆, 3600±300 cal·mol⁻¹. The use of the solubility parameter for the interpretation of the data in the extraction of iodine is investigated. The data obtained in multiple extractions are treated by using the analogy between extraction and radioactive decay. The half number of extraction for each system is determined. The complex curves obtained in the H₂O(I₂)−CCl₄ and H₂O(I₂) −Br₂)−CCl₄ systems are resolved into two components.     

Charge-transfer polymerization of butyl methacrylate

Butyl methacrylate (BuMA) can be polymerized by charge-transfer complexes formed by the interaction of ethanolamine (EA), BuMA, and carbon tetrachloride (CCl₄) in a non-aqueous solvent, such as N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO). The rate of polymerizationR _p is found to be linear with [BuMA] and proportional to both [CCl₄]^0.5 and [EA]^0.5 when [CCl₄]/[EA]≤1.R _p becomes independent of [CCl₄] when [CCl₄]/[EA]>1.R _p is proportional to [EA]^0.56 and to [BuMA]^1.30 when [CCl₄]>[EA]. The average rate constant at 30°C for the polymerization of BuMA in terms of monomer was 3.32×10⁻⁶ s⁻¹ when [CCl₄]/[EA]≤1, and 5.47×10⁻⁶ L/(mol s) when [CCl₄]/[EA]>1.     

2-Ferrocenyl-substituted pyrylium ions from coupling of ethynylferrocene with cyclomanganated chalcones

2-Ferrocenyl-substituted pyrylium salts are produced when orthomanganated chalcones are reacted with ethynylferrocene in CCl₄. When the reaction is carried out in benzene, intermediate ferrocenyl-substituted (η⁵-pyranyl)Mn(CO)₃ species can be isolated which give the pyrylium cations on oxidation. The electrochemistry of the 2-ferrocenyl-pyrylium cations shows both oxidation (of the ferrocenyl) and reduction (of the pyrylium) processes, and the UV-visible spectra show a broad band at ca 680 nm which can be assigned to an intramolecular charge transfer transition.     

A sensitive spectrophotometric method for determination of carbon tetrachloride with the aid of ultrasonic decolorization of methyl orange

A sensitive method for carbon tetrachloride (CCl₄) determination has been developed with the aid of ultrasonic oxidation decolorization of methyl orange (MO). It is found that the ultrasonic oxidation decolorization rate of MO can be significantly promoted by adding a little amount of CCl₄. The increased ultrasonic decolorization rate of MO is strongly dependent on the concentration of CCl₄ added, and a linear correlation is observed between the amount of CCl₄ and the decolorization rate of MO in the ultrasonic oxidation process. Thus, the CCl₄ determination is transformed to a simple and direct determination of the decoloration extent of MO solution at a given concentration. As an indirect spectrophotometric determination of CCl₄, the new method is sensitive and easy of operation with a maximum wavelength of 508 nm, molar absorptivity of 3.83 × 10⁴ L mol⁻¹ cm⁻¹, and a Sandell sensitivity of 7.96 × 10⁻³ μg cm⁻². Under optimized conditions, Beer's law is obeyed in the range of 0.4-20 mg L⁻¹ of CCl₄ (DL = 0.19 mg L⁻¹, r = 0.9996). The concentrations of CCl₄ in several practical samples have been determined satisfactorily by using this method.     

Electrocarboxylation of CCI<Subscript>4</Subscript> in MeCN during electrolysis with the sacrificial Zn anode

The regularities of galvanostatic electrocarboxylation of CCl₄ in Alk₄NBr/MeCN in an undivided cell with sacrificial Zn anode were studied. The major product of the electrolysis is zinc trichloroacetate, which is formed as a result of the reaction of the cathode-generated CCl₃- anion with CO₂. The further trichloroacetate reduction is prevented by cathode passivation. Therefore, small amounts of zinc dichloro- and monochloroacetates are formed due to the chemical reduction of zinc trichloroacetate with Zn⁰ rather than the cathodic reduction. Zero-valence zinc is formed in minor amounts when Zn²⁺ ions are discharged at the cathode surface because of the low solubility of ZnBr₂ in MeCN. The treatment of (Cl₃CCOO)₂Zn with H₂SO₄ in MeOH gives Cl₃CCO₂Me in 11% yield based on the starting CCl₄.     

Fullerene C60 Trichloromethylation Through CCl4 Plasmalysis or Sonolysis

The trichloromethylation of C₆₀ fullerene was achieved either under plasmalysis conditions, i.e. by arcing a solution of C₆₀ in CCl₄ between two graphite electrodes, or by sonolysis of C₆₀ in CCl₄. The resulting products were studied by UV–VIS and FT-IR spectroscopy as well as by thermogravimetric analysis in comparison to the trichloromethyl adducts formed by radiolysis or photolysis of C₆₀ in CCl₄. A reference study on the plasmalysis of pure CCl₄ has revealed the formation of carbon soot and hexachlorobenzene. The formation of the latter compound was suppressed when C₆₀ was present in CCl₄.     

Polymerization of methyl methacrylate by a charge transfer mechanism with urea and iron (III) complex

Methyl methacrylate (MMA) can be polymerized by a charge transfer complex formed by the interaction of urea, methyl methacrylate, and carbon tetrachloride (CCl₄) in a nonaqueous solvent like dimethylsulfoxide (DMSO). The rate of polymerization can be accelerated by Lewis acids like Fe³⁺. This article reports the polymerization of MMA initiated by urea and CCl₄ and accelerated with hexakisdimethylsulfoxide iron (III) perchlorate, [Fe(DMSO)₆](ClO₄)₃, and A at 60°C. Definite induction periods were observed for the polymerization reaction initiated by urea and CCl₄ alone, but the induction period completely vanished when the molar ratio of urea to A reached 6:1. The molecular weights of the polymers with 6:1 molar ratio of urea to A were higher than with urea alone. The rate constant for the polymerization of MMA in the presence of [Fe(urea)₆]³⁺ was 1.03 × 10^?5 1 mol^?1 s^?1 at 60°C. The transfer constant for CCl₄ for polymerization with urea alone is 2.43 × 10^?3 at 60°C.     

An indirect method for the electrosynthesis of monochloroamine

An indirect two-stage method for the electrosynthesis of NH₂Cl was elaborated. In the first stage, NH₄Cl was electrolyzed in a nondivided cell in the NaCl (aqueous solution)—CCl₄ heterophase system to give NCl₃ as a solution in CCl₄. Under the optimum conditions, the yield of NCl₃ was 80%, and the current efficiency 60%. In the second stage, the obtained solution reacted with an aqueous solution of NH₃ to give an aqueous solution of NH₂Cl in 50% yield (converted to NH₃). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2011–2014, October, 1998.     

Stabilization of CCl4− radical anions in glassy matrices at low temperatures

Optical spectrophotometry has been used to investigate the product of electron addition to CCl₄ in solvents of different nature. It is shown that in “rigid” matrices (η > 10¹⁹ P) CCl₄⁻ radical anions are formed, whereas in a “soft” environment (η < 10¹⁹ P) CCl₄⁻ undergoes dissociation into CCl₃ radicals and Cl⁻ ions. The possible reasons for stabilization of the CCl₄⁻ radical anions in solid media are discussed.     

Radiolysis of carbon tetrachloride-nitrobenzene mixtures. Radiation yields of major liquid products

The yields of major non-gaseous radiolytical products in the mixtures of carbon tetrachloride-nitrobenzene in a wide concentration scale have been established and found to depend on the composition of the mixture. Decrease of the yield hexachloroethane with increasing concentration of nitrobenzene was explained by the energy transfer from CCl₄ to the molecule of C₆H₅NO₂. Chlorobenzene is formed from an exciplex [CCl₄.C₆H₅NO₂]^* or complex with charge transfer or from reaction of the excited molecules of nitrobenzene, and the formation of dichlorobenzenes, trichlorobenzenes and chloronitrobenzene can be explained by radical substitutional reactions.Dedicated to Prof. V. D. Nefedov on the occasion of his 70th birthday     

A Novel Thermooptical Detection Method for Enzyme Reaction Based on the Optical Beam Deflection Induced by Reaction Heat

A novel thermooptical detection method for enzyme reaction based on the optical beam deflection induced by reaction heat is proposed. A probe beam passes through a CCl₄ phase above which a model enzyme reaction occurs. The enzyme reaction medium is arranged to be either interfaced directly with the CCl₄ phase or separated from the CCl₄ phase by a thin gold film. The decomposition reaction of hydrogen peroxide catalyzed by catalase is used as a model enzyme reaction. In the arrangement that the reaction medium is interfaced directly with the CCl₄ phase, both the reaction heat and the reaction product O₂ diffuse into the CCl₄ phase, and thus generate temperature and concentration gradients, respectively. Since both the temperature and concentration gradients induce the deflections of the probe beam, two peaks are observed in the deflection signal. On the other hand, in the arrangement that the reaction medium is separated from the CCl₄ phase by the gold film, only the deflection signal generated by the temperature gradient is detected. The quantitative relations between the deflection signals induced by the reaction heat and the concentrations of catalase and H₂O₂ are investigated. Under the present batch experimental conditions, deflection signals are linear in the concentration ranges of 4 × 10⁻³-4 × 10⁻² mol/liter for H₂O₂, and 11-550 μg/ml (activity, 11-550 unit/ml) for catalase solution, respectively. The detection limits for H₂O₂ and catalase solution are 4 × 10⁻³ mol/liter and 11 μg/ml (activity, 11 unit/ml), respectively. In addition, the possibilities of development as a new thermooptical biosensor and application to the determination of activity distribution of this method are also discussed.     

Polymerization of methyl methacrylate by charge transfer mechanism by melamine and iron(III) complex

Methyl methacrylate (MMA) can be polymerized by the charge-transfer complex formed by the interaction of melamine (MM), MMA and carbon tetrachloride in a non-aqueous solvent like dimethyl sulphoxide (DMSO) or N-N-dimethylformamide. The polymerization can be accelerated by Lewis acids like Fe^3?. This paper reports the polymerization of MMA initiated by MM and CCl₄ and accelerated with hexakis dimethylsulphoxide iron(III) perchlorate [Fe(DMSO)₆] (ClO₄)₃. A, at 60°. Induction periods were observed for the polymerization initiated by MM and CCl₄ alone, but not when the molar ratio of MM to A became 3:1. The molecular weights of the polymers with 3:1 molar ratio of MM to A were higher than with MM alone. The rate constant for the polymerization of MMA in presence of [Fe(MM)₃]³⁺ was 1.4181 × 10^?5 1 mol^?1 sec^?1 at 60°. The transfer constant for CCl₄, in the absence of A, is 4.66 × 10^?3.     

Study of the reaction of sulfur with organic compounds

The reaction of sulfur with phenylchloromethanes of the type (C₆H₅)_mCCl_nH_{4-m -n}(m=1–3; n3) is investigated. New simple methods of synthesizing tetraphenylthiophene (from C₆H₅CH₂Cl) and thianaphtheno [3, 2-b] thianapthene or 2-phenyl-3-chlorothianaphthene (from C₆H₅CHCl₂) are developed. All the heterocyclic sulfur compounds synthesized are oxidized to the corresponding sulfones, Diphenylchloromethane when heated with sulfur smoothly gives a high yield of tetraphenylethylene, and triphenylchloromethane treated similarly gives triphenylmethane. C₆H₅CCl₃ and (C₆H₅)₂CCl₂ undergo practically no reaction with sulfur under the conditions investigated.For Part VII see [1].     

Dichloromethyleneamides of dialkyl phosphates

Summary Dichloromethyleneamide dialkyl phosphates (AlkO)₂P(O)N=CCl₂ (alkyl: C₂H₅,C₃H₇, i-C₃H₇, C₄H₉, i-C₄H₉) were obtained by reaction between chlorine and the corresponding isothiocyanatophosphate esters. The dichlorides obtained reacted vigorously with amines, alcohols, and alcoholates.Translated from Izvestiya Akademii Nauk SSR, Seriya Khimicheskaya, No. 5, pp. 932–933, May, 1964     

Charge Transfer Complex Role in the Formation of Chlorobenzene in the γ‐Irradiated Carbon Tetrachloride‐Benzene System

The formation of carbon tetrachloride‐benzene charge transfer complex was confirmed by UV and NMR spectrometric studies. A change in UV spectrum of benzene is observed upon addition of carbon tetrachloride. Whereas the appearance of new bands supports the formation of charge transfer complex. NMR study shows that, chemical shift of benzene pmr signal depends on the CCl₄‐C₆H₆ molar ratio. This observation is another criterion for the formation of benzene‐carbon tetrachloride charge transfer complex. Job's Continuous Variation method indicates that a 2:1 CCl₄‐C₆H₆ charge transfer complex (2:1 CTC) is formed. The association constants (K_2:1) of (2:1 CTC) was found to be 0.0197 M^?2. The maximum concentration of (2:1 CTC) was found to be in samples with 2:1 CCl₄‐C₆H₆ molar ratio (33% benzene mole). On the other hand the maximum yield of chlorobenzene was obtained, also, upon radiolysis of CCl₄‐C₆H₆ samples at a 2:1 molar ratio (33% benzene mole). Therefore, it could be concluded that (2:1 CTC) participates in the formation of chlorobenzene upon radiolysis of the benzene‐carbon tetrachloride system. This conclusion was supported by the dependence of the chlorobenzene yield of a γ‐irradiated carbon tetrachloride‐benzene system (2:1 molar ratio) on irradiation time according to a third order kinetic equation with a very good linearity (R² = 0.9977). Accordingly, the rate constant for the chlorobenzene formation under this condition was found to be ≈ 5.5 × 10^?7 L².mol^?2.h^?1. We propose a radiation chemical mechanism in which the 2:1 CTC plays a role in the formation of chlorobenzene.     

Extraction of Np(IV) and HNO3 by Triphenylphosphine Oxide

The extraction of Np(IV) and HNO₃ from aqueous solutions containing only this acid (1–10 M) has been studied with solutions of triphenylphosphine oxide (TPPO) in carbon tetrachloride, benzene and chloroform. The species TPPO · HNO₃ and Np(NO₃)₄ · 2TPPO are the most predominently extracted species; there is also experimental evidence for Np(NO₃)₄ · TPPO. An equilibrium “constant” of 0.7 is calculated for the extraction of HNO₃ with solutions of the reagent in CCl₄. This value is found to fit also the measurements on TPPO in C₆H₆. The position of the solvent CHCl₃ is reversed, compared with the extraction of the acid and Np(IV) by the solvents CCl₄ and C₆H₆, respectively.