Catalysis of the hydrolysis of esters of phosphorus acids byn-decylammonium chloride /n-decylamine mixed micelles

The effect ofn-decylammonium chloride/n-decylamine mixed micelles on the rate of hydrolysis of aryl esters of acids of four-coordinate phosphorus was studied spectrophotometrically. The shape of the concentration curves is characteristic of the micellar catalysis reactions. The binding constants of the substrate, critical micelle concentrations, and the rate constants in the micellar phase were determined. A specific effect of the structure of substrates on these parameters was shown.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2003–2006, August, 1996.     

An equation for the calculation of retention indices in temperature-programmed gas chromatography with allowance for the nonlinear variation of the retention parameters ofn-alkanes

In view of the nonlinear variation of the temperature increments ofn-alkanes found previously, the accuracy of the calculations of the retention indices (I _pr) of substances in temperature-programmed capillary gas chromatography carried out in terms of six known equations was verified. A new four-parameter equation was proposed, and a general method for the calculation of its coefficients, suitable for all stationary phases, based on the adjusted retention times ofn-alkanes was suggested. The coefficients of the equation for 12 temperature variation programs were determined. Using the homologous series of methyl esters of fatty acids as an example, it was shown that the proposed equation ensures the minimum error of determination ofI _pr under various conditions. The equation also makes it possible to carry out interpolation and extrapolation calculations. The coefficients of the equation are found using the least-squares method based on data for any 4–5 referencen-alkanes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 323–327, February, 1997.     

Reactivity of polymer substituents. Aminolysis of p-nitrophenyl ester residues attached to various polymer backbones

Styrene, methyl acrylate, and N,N-dimethylacrylamide were copolymerized with small proportions of p-nitrophenyl acrylate or p-nitrophenyl esters of CH₂?CHCONH(CH₂)_nCOOH (n = 1,3,5). The aminolysis of these copolymers in dioxane and chlorobenzene solution was compared with the corresponding reaction of low molecular weight analogs. The ratio of the reactivity of the polymer substituent and its analog was found to be insensitive to the nature of the amine but strongly dependent on the nature of the polymer backbone. Poly(dimethylacrylamide) chains carrying active ester substituents were in some cases much more reactive than their analogs due to the activating effect of the dimethylamide groups. In the case of the p-nitrophenyl acrylate–styrene copolymer, the aminolysis exhibited a dispersion of the rate constant due to its sensitivity to stereoisomerism in the vicinity of the active ester, but no similar effects were observed with the other copolymers.     

Investigation of the reaction of peroxide radicals derived from di-n-butyl ether withp-phenylenediamine by kinetic spectrophotometry

The kinetics of consumption ofp-phenylenediamine (PDA) in di-n-butyl ether (BE) subjected to oxidation was measured by following the accumulation of the product of the transformation of PDA. The effective rate constant of the reaction of peroxide radicals derived from BE (RO₂) with PDA was measured (k ₇ = 2·10⁴ L mol^–1 s-1) by the inhibitor method, Evidence confirming the formation of a stable complex of RO₂, with PDA were obtained. This leads to retardation of oxidation without the formation of hydroperoxides of BE (ROOH) in the acts of chain termination on PDA.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 12, pp. 2902–2903, December, 1996.     

Study of the transmetallation of silicon derivatives ofo-carboranes on treatment with BunLi

Silyl-substitutedo-carboranes 1-R-2-Me₃Si(CH₂) _n -1,2-C₂B₁₀H₁₀ (R=Me, Ph;n=0, 1) undergo transmetallation on treatment with BuⁿLi to form lithium derivatives ofo-carboranes, 1-R-2-Li(CH₂) _n -1,2-C₂B₁₀H₁₀, wheren=0, 1. A silicon derivative ofo-carborane, 1-Ph-2-(Me₃SiCHPh)-1,2-C₂B₁₀H₁₀, undergoes neither transmetallation nor metallation at the benzyl CH-group on treatment with BuⁿLi due to significant steric hindrance. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 492–494, March, 1998.     

Untersuchungen zurFriedel-Crafts-Reaktion. XVI. Darstellung isomerer 2-Acyl- und 3-Acyl-4-methoxyphenole

Acylation of 4-methoxy phenol according toFriedel andCrafts, as well as the rearrangement of its esters according toFries lead always to 2-acyl-4-methoxy phenols or to their demethylated compounds. The unknown 3-acyl-4-methoxy phenols were prepared in two steps: First, the ester is acylated with the corresponding acyl chloride and SnCl₄ in nitromethane. In the second step the resulting ketoesters are hydrolysed. This is a general method. The yields ofmeta-acylphenols are between 40 and 90%. The isomeric 2-acyl-4-methoxy-phenols which were partly unknown or accessible only in low yields have also been prepared for comparative spectral studies (UV, IR, NMR, MS) ofortho- andmeta-acylphenols.

     

2-(N-Alkyl-p-hydroxyanilino)-1,4-benzochinone ausp-Benzochinonen und primären aliphatischen Aminen

In acetic (aqueous or chloroform) solutionp-benzoquinones yield with primary aliphatic amines mainly 2-(N-alkyl-p-hydroxy-anilino)-1,4-benzoquinones besides the 2-alkylamino- and 2,5-bis(alkylamino)-quinones. The methyl-, ethyl-,n-propyl-,n-butylhomologues ofp-benzoquinone and the isomer methylderivatives of toluquinone are described. Their structure were established by spectroscopic (UV/VIS, IR, NMR) methods and by synthesis of the methylderivative3 a fromp-benzoquinone andp-hydroxy-N-methylaniline. The influence of other acids on the reaction was studied.

Herrn Prof. Dr.G. Zigeuner, Universität Graz, mit den besten Wünschen zum 60. Geburtstag gewidmet.     

Temperature dependence of the free energy of sorption ofn-alkanes and energy contribution of their methylene groups on columns with fullerene C60

The partial molar free energy, enthalpy, and entropy of sorption of C₁₁−C₂₃ n-alkanes were calculated on the basis of the GC data obtained on the glass capillary column coated with fullerene C₆₀ (Ful-60) as stationary phase. The thermodynamic parameters ofn-alkane sorption on a column with Ful-60 and a fused silica capillary column with polydimethylsiloxane OV-1 were determined and compared. The enthalpy-entropy compensation effect for the sorption ofn-alkanes on Ful-60 and OV-1 was found. A linear dependence of the partial molar free energy ofn-alkane sorption on the temperature of analysis and carbon chain length was found. The free energy contributions of the methylene groups were calculated, and their temperature dependences were studied. The differences in the temperature dependences of the energy contributions of methylene groups ofn-alkanes on Ful-60 and OV-1 were revealed. The entropy contribution is 68–82% of the enthalpy contribution which indicates a substantial role of the number of contacts with Ful-60 in retention ofn-alkanes. The ability of Ful-60 for dispersive interactions is similar to those of nonpolar liquid phases and substantially differs from that for carbon adsorbents. Fullerene columns were shown to be convenient for analysis of highly boiling organic substances in aqueous and organic solutions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1490–1495, August, 1999.     

Isomerization ofn-butane on the SO4/ZrO2 catalyst promoted by IV Period metals

The catalytic activity of superacidic systems based on SO₄/ZrO₂ and modified by IV Period metals in isomerization ofn-butane was studied. At low temperatures of the reaction, the introduction of Fe³⁺, Sc³⁺, Co²⁺, or Zn²⁺ ions (1%) increases the yield of isobutane by 1.5 times due to the activation ofn-butane on the sites created by the promoting ions. The addition of Cr³⁺, V⁴⁺, or Mn²⁺ (1%) decreases the catalytic activity because of a decrease in the catalyst acidity, most likely, due to the reduction of surface sulfur species. The influence of the nature of the support and surface additives of SiO₂, TiO₂, and ZrO₂ on the activity and selectivity of the catalytic system inn-butane isomerization was studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7 pp. 1276–1280, July, 1999     

Inequality of temperature increments ofn-alkane homologs as one of the reasons for the nonlinear variation of sorption parameters of substances in temperature-programmed gas chromatography

GC behavior of C₆-C₁₇ n-alkanes has been investigated at different temperatures of isothermal analysis and under temperature programming conditions using two capillary columns coated with OV-101 and OV-351 stationary phases. Temperature increments have been calculated for the homologs and their inequality has been demonstrated for each member of then-alkane series. It was shown that the nonlinear individual temperature variation of the energy of dispersive interaction ofn-alkane homologs with the stationary phase, which was observed under isothermal conditions, may be one of the main reasons for the nonlinear change in sorption parameters ofn-alkanes in temperature-programmed gas chromatography.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 642–645, April, 1994.The present work was carried out with the financial support of the Russian Foundation for Basic Research (Grant 93-03-4969).     

Change in the reactivity of di-tert-butyl peroxide during homolysis with an increase in the degree of conversion and pressure

It was found that the differential reactivity (k _d ) of di-tert-butyl peroxide (DTBP) in a solution of 2-methoxy-(1) and 2-ethoxytetrahydropyran (2) at 130°C and pressuresp=20 and 1000 MPa is a periodic function of the degree of conversion, arbitrarily measured by the concentration oftert-butyl alcohol (TBA) formed. The functionk _d =F([TBA]) was calculated with the spline approximation (SA) of the experimental [TBA] as a function of the reaction time , giving a continuous curve of d[TBA]/d as a function of . The integral reactivityk _d =G([TBA]) calculated with the kinetic equation for a first-order reaction for decomposition of DTBP in1, 2, 1 + C ₆ H ₆ and2 + C ₆ H ₆ in three segments of in the range ofp=20–1000 MPa changes differently with an increase in the degree of conversion for differentp. The volume activation effects ( ) determined by SA of the experimental lnk _d as a function ofp were calculated for close degrees of conversion, [TBA]=0.1–0.14M. The as a function ofp obtained were compared with the similarly processed published data on decomposition of DTBP inn-heptane and dicumyl peroxide (DCP) in different aromatic solvents. The results were attributed to the effect of the type of packing of the solvent molecules surrounding the reacting molecule on the reactivity of the peroxide and not to the effect of radical recombination in the primary cage.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 117913. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 829–837, April, 1992.     

Formation of pore structure in group 4 binary oxides crystallizing with difficulty

Influence of the addition of phenanthrene on the hydroconversion ofn-heptane on an industrially coked catalyst has been studied. Phenanthrene behaves like an inhibitor in the following way 1/r_nh (mol/h/g)⁻¹=447+236 p_ph (kPa)     

Gas-chromatographic method of evaluation ofn-alkanol ability for self-association in pure liquid

The values of the gas-chromatographic indicator reflecting the capacity of analytes for self-association in pure liquids, δT _b.p., were estimated for C₁–C₉ and C₁₁ n-alkanols by capillary gas chromatography on a nonpolar stationary phase under isothermal conditions. The δT _b.p. values ofn-alkanols, found as the difference between the boiling points measured directly and those calculated from GC data, are correlated with thermodynamic characteristics of the formation ofn-alkanol associates in pure liquids. Usingn-alkanols as analytes with insignificant temperature increments of the retention indices, it was shown that the δT _b.p. values can be determined under conditions used in gas chromatography with temperature programming. In this way a single chromatographic run can be used to compare the capacities for self-association of analytes boiling over a wide temperature range. The C₂–C₉ n-alkanethiols, which are not associated in neat liquids, have negative δT _b.p. values. An interpretation of this finding is proposed. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 315–318 February, 2000.     

Oxidation of aliphatic alcohols with the lead tetraacetate—metal halide system under mechanical activation

The mechanochemical oxidation ofn-pentanol,n-hexanol, andn-octanol with the Pb(OAc)₄-MHal system (M=Li, K; Hal=Cl, Br) in the absence of a solvent affords esters. and secondary alcohols with the composition C₈H₁₇OH and C₉H₁₉OH give ketones. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1870–1873, November, 2000.     

Encapsulating property of ap-t-butylcalix[6]arene derivative: Formation of charge-transfer complexes of alkadienes with iodine in the presence of octopus-type calix[6]arene

This paper deals with the ability ofp-tert-butylcalix[6]arene derivative1, which has six 3,6,9-trioxadecyl substituents at the phenolic oxygens, to encapsulate CT complexes of alkadienes with iodine. By adding I₂ to alkadienes in CH₂Cl₂ in the presence of1, the absorbance at 363 nm, which was ascribed to I ₃ ^– ion, increased in the order: 1,5-hexadiene<1,9-decadiene 1,7-octadiene. The reactivity features of the CT complexes in the presence of1 are discussed.     

Temperature dependence of excess enthalpies for systems containing normal hexadecane

Excess enthalpies, and heat capacities derived therefrom, have been obtained between 25 and 65 or 75°C at a constant concentration for cyclohexane and octamethylcyclotetrasiloxane mixed with normal hexadecane and with a highly branched C₁₆ isomer, 2,2,4,4,6,8,8-heptamethylnonane, and also forcis-andtrans-decalin mixed withn-C₁₆. Theh ^E values withn-C₁₆ are positive and much larger than with the branched-C₁₆. They decrease rapidly withT so thatc _p ^E is large and negative. These results imply the presence of orientational order in then-C₁₆, which is destroyed on mixing with the other component and which decreases withT. Theh ^E fortrans-decalin+n-C₁₆ is much smaller than forcis-decalin+n-C₁₆, and becomes negative with increase ofT. This change of sign, which is unexplained by current theory, is interpreted as due to an interference of the flat, plateliketrans-decalin molecule with the molecular motion of then-C₁₆ chain.     

Photoreduction ofortho-benzoquinones in the presence ofpara-substitutedN,N-dimethylanilines

Photoreduction ofo-benzoquinones irradiated at the wavelengths λ_max ≈ 400 and 600 nm corresponding to the S(π → π*) and S(n → π*) electron transitions in the >C=0 groups, respectively, in the presence ofN,N-dimethylaniline and its derivatives was studied. The apparent rate constants of the photoreduction (k _H) ofo-quinones are determined by the free energy of electron transfer from the amine molecule to a photoexcitedo-quinone molecule (ΔG _e.t). The ΔG _e.t. values are calculated as the sums of the energies of the 0→0 transitions of the lowest triplet excited state ofo-quinones, the reduction energies ofo-quinones, and the oxidation energies of amines (the last two terms are numerically equal to the corresponding redox potentials). The maximum rate of photoreduction was found for ΔG _e.t≈0. The reaction mechanism is proposed, in which the reversible formation of a triplet exiplex is the rate-determining stage and hydrogen transfer proceeds in parallel with electron transfer within the exiplex. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1515–1521, September, 2000.     

Variation in the sorption energy of esters ofn-perfluoroalkanoic acids on chromatographic phases of different polarity

The contributions of methylene and difluoromethylene units of six homologous and six pseudohomologous series of esters ofn-perfluoroalkanoic acids to the differential molar free energy, enthalpy, and entropy of sorption on stationary phases of different polarities in glass capillary columns under isothermal conditions were calculated. The features observed characterize the peculiarities of the sorption of esters of polyfluorinated carboxylic acids on phases of different polarities and make it possible to estimate the enthalpy and entropy contributions to the energy of sorption of the esters, the effect of the temperature of the analysis and the length of the alkyl or polyfluoroalkyl chain on the retention parameters of the compound analyzed. The inversion of the retention order of trifluoroacetates and pentafluoropropionates in XE-60 nitrile-containing phase was found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2051–2055, December, 1993.     

Comparative study of the reactions ofn-BuMgBr andn-BuLi with cyclododecanone

The composition of the products obtained in the reactions ofn-BuMgBr andn-BuLi with cyclodecanone (1) has revealed that1 exhibits the properties of a sterically hindered ketone. The highest yield of 1-butylcyclododecanol (2) was achieved with the use ofn-BuMgBr, but in this case cyclododecanol was also formed, whereas the use ofn-BuLi led to the tertiary alcohol more distinctly. Dehydration of alcohol2 resulted in a mixture of three olefins containing up to 90 % ofE- andZ- isomers of 1-butylcyclododecene.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 907–909, May, 1993.     

Isocamphananaloge mandelsäure

The synthesis of some new potentially, nitrogenefree spasmolytics is described. Formally the benzene nucleus in some mandelic acid esters, known by their mild spasmolytic activity, is substituted for the isocamphane bicyclus by a) SeO₂ oxidation of 1-(3,3-Dimethyl-2-exo-norbornyl)-ethanone (5) to the corresponding ketoaldehyde6, b) oxidation of6 to the isocamphane analogous mandelic acid4 and c) esterification of derivatives of4 with isoamylalcohol and benzylalcohol. Attemps to dehydrate the methylester7 to camphenylideneacetic acid methylester (12) by various methods failed, probably because of the ring strain.

Teil der Diplomarbeit vonB. Blach, Universität Wien 1981.