bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion of gases in liquids: the constant size bubble method
Authors: Ng Wing Y. , Walkley John
Published: May 2006

A method is described by which the diffusion of a gas in a liquid is measured by maintaining a bubble of the gas at constant size in the liquid. A steady state solution to the diffusion equation is seen to fit the observed experimental data. The measured diffusion coefficients for nitrogen, oxygen, and carbon dioxide in water at 25 °C are found in good agreement with previously determined values.
Reaction of dihalocarbene with N,N-dimethylaniline
Authors: Saraf S. D.
Published: May 2006

The reaction of dihalocarbenes with N,N-dimethylaniline is discussed. α,α-Dihaloacetanilides and 4,4′-dimethylaminodiphenylmethane were the products isolated.
Formation of a C22 dihydroxyketo acid by a yeast
Authors: Vesonder Ronald F. , Stodola Frank H.
Published: May 2006

Saponification of extracellular lipids from the yeast NRRL YB-2501 yielded 8,9,13-trihydroxydocosanoic acid and a new keto dihydroxy acid of melting point 131–132 °C. The keto acid was shown to be 8,9-dihydroxy-13-oxodocosanoic acid by conversion to 5-ketotetradecanoic acid and suberic acid. By means of the method of Ames and Bowman (3), it was established that the vicinal hydroxyls of the new acid have the erythro configuration.
Microwave spectrum and conformation of tetrahydropyran
Authors: Rao V. M. , Kewley R.
Published: May 2006

The microwave spectrum of tetrahydropyran has been recorded in the region 8–40 GHz. The rotational constants of the molecule in its ground vibrational state are, in MHz, A = 4673.48 ± 0.05, B = 4495.02 ± 0.11, and C = 2601.31 ± 0.05. The dipole moment components are, in Debye units, μa = 1.53 ± 0.02, μc = 0.82 ± 0.02, and μ = 1.74 ± 0.03. The direction of μ with respect to the principal axes of rotation together with the rotational constants show that the observed spectrum is due to the chair form of tetrahydropyran.
Solvation thermodynamics of ions: free energies in water, ammonia, and fused LiCl–KCl eutectic
Authors: Plambeck James A.
Published: May 2006

Conventional free energies of solvation of ions are calculated from appropriate thermodynamic data in water, liquid ammonia, and fused LiCl–KCl eutectic. These are fitted to a modified Born-charging equation, whose origin and significance are discussed. Statistical tests are applied to certain aspects of the form of the equation. Parameters obtained from the equation can be used to calculate the free energies of solvation of single ions.
Thermal reaction of the U(VI) and Th(IV) 8-hydroxyquinoline adducts
Authors: Corsini A. , Abraham J.
Published: May 2006

The use of [14C]-8-hydroxyquinoline has shown that when the 8-hydroxyquinoline adducts, [Formula: see text] and Th(C9H6NO)4•C9H7NO, are thermally converted to the normal compounds, UO2(C9H6NO)2 and Th(C9H6NO)4, intermolecular ligand exchange in the solid phase occurs. The extent to which the exchange equilibrium proceeds suggests that the thermal energy absorbed is sufficient to promote considerable metal–ligand bond rupture.
Distortions in tetrahedral copper(I)–phosphine complexes: bis(triphenylphosphine)copper(I) nitrate
Authors: Messmer G. G. , Palenik Gus J.
Published: May 2006

The crystal structure of bis(triphenylphosphine)copper(I) nitrate has been determined by a three-dimensional X-ray diffraction study. The copper(I) atom is bonded to the two phosphines and two oxygen atoms of the nitrate group. However, the molecule is distorted from that of an ideal tetrahedron, with the P—Cu—P angle being 131.1°.
Kinetic isotope effect for the thermally-induced migration of hydrogen in cyclopentadienes
Authors: McLean Stewart , Webster C. J. , Rutherford R. J. D.
Published: May 2006

The Arrhenius parameters have been obtained for the rearrangement of 5-methylcyclopentadiene by a 1,2-hydrogen migration and for the corresponding rearrangement of 5-methylpentadeuteriocyclopentadiene. The results, taken in conjunction with those reported previously, allow the effect of the methyl group on the rate of hydrogen migration to be assessed. The kinetic isotope effect is of particular interest because the hydrogen transfer takes place through a transition state that is unequivocally non-linear.
Vibrational spectra and a force field for H2S3 and H2S4
Authors: Wieser H. , Krueger P. J. , Muller E. , Hyne J. B.
Published: May 2006

The infrared and Raman spectra of H2S3 and H2S4 in CCl4 and CS2 solutions are reported and a complete assignment is presented. On the basis of the spectra and their temperature and concentration dependence, H2S3 is considered to be in the GG and H2S4 in the GG′G conformation. A valence force field is derived which provides a least-squares fit between observed and calculated frequencies for both molecules simultaneously, with an average error of 1.5 cm−1 (or 0.4%) over all frequencies.
Complexes of Co(II), Ni(II), and Zn(II) with pyrazolone ligands
Authors: Bailey R. A. , Peterson T. R.
Published: May 2006

Complexes of Co(II), Ni(II), and Zn(II) with 4-aminoantipyrine and 4-dimethylaminoantipyrine have been prepared and characterized. These contain chloride, bromide, thiocyanate, nitrate, and perchlorate anions. Magnetic, conductivity, and electronic spectral data show that all of the Ni(II) and Co(II) complexes have high spin configurations and octahedral geometries, with coordinated halide, thiocyanate, and probably nitrate anions in the respective examples. Infrared analysis indicates that all of the complexes containing Cl−, NCS−, and NO3− anions involve chelated 4-aminoantipyrine, whereas the bromide complexes are only bonded to the organic ligands through nitrogen.
Inelastic scattering of high energy electrons by atmospheric gases
Authors: Lassettre Edwin N.
Published: May 2006

Inelastic scattering of electrons by nitrogen, oxygen, carbon monoxide, carbon dioxide, water, argon, and helium is reviewed. Electron impact spectra at both high (less than 40 keV) and low (greater than 15 eV) kinetic energies are presented and discussed. Collision cross sections and generalized oscillator strengths are described, when data are available, and the connection with optical oscillator strengths is discussed. The limiting selection rules which hold in the excitation of atoms and molecules by electron impact are discussed and typical examples of forbidden transitions are described.
Comments, Replies, and Summary
Authors: Hunten D. M.
Published: May 2006

not available
Comments
Authors: Lint V. A. J. van
Published: May 2006

not available
Absorption in the spectral range of the Schumann–Runge bands
Authors: Ackerman M. , Biaume F. , Nicolet M.
Published: May 2006

Absorption of silicon lines by O2 in the Schumann–Runge bands has been measured. The results lead to some conclusions about the nature of the absorption and about the general behavior of the spectrum.
Chemiluminescent reactions of He(23S) atoms
Authors: Cher Mark , Hollingsworth C. S.
Published: May 2006

Rate coefficients for the reactions of He(23S) atoms with N2, O2, CO, and CO2 were determined by measuring the fractional absorption of 3889 Å light from a helium lamp as a function of the concentration of the neutral gas in a flowing afterglow apparatus. The rate coefficients are in reasonable agreement with those obtained previously from measurements of the emission intensity. It is concluded that the observed chemiluminescence arises from Penning ionization reactions involving the He(23S) atom.
Configuration of echinulin. II. Optical rotatory dispersion of echinulin, hydroechinulin, and the stereoisomeric 3-methyl-6(indolyl-3-methyl)-piperazine-2,5-diones
Authors: Nakashima R. , Slater G. P.
Published: May 2006

The optical rotatory dispersion spectra of echinulin and hydroechinulin have been compared with the spectra of the 4 stereoisomers of cyclo-alanyltryptophan. The results indicate appreciable differences in the spectra of the cis- and trans-piperazinediones and that echinulin has the cyclo-L-alanyl-L-tryptophan configuration.
Gas–liquid chromatography of terpenes. Part XVIII. The volatile oil of the leaves of Juniperus communis L.
Authors: Rudloff E. von , Sood V. K.
Published: May 2006

The volatile leaf oil of the local common juniper was found to consist mainly of α-pinene (73 to 83%) and smaller amounts (0.5 to 5%) of β-pinene, 3-carene, myrcene, limonene, methyl citronellate, bornyl acetate, myrtenal, myrtenol, myrtenyl acetate, α-terpineol, citronellol, citronellyl acetate, nerolidol, farnesol, and an unusual hydroxy ketone. Of the many trace constituents, β-phellandrene, citronellal, "iso-" citronellal, linalool, geraniol, isopulegol, 4-terpinenol, and ε-cadinene were isolated, whereas camphene, sabinene, α-phellandrene, γ-terpinene, terpinolene, p-cymene, fenchone, thujone, isothujone and δ-cadinene could only be tentatively identified.There was little variation in the quantitative composition of the leaf oil from one plant to another. Since the composition of this oil differs significantly from that of other juniper leaf oils, chemotaxonomic studies by means of leaf oil analysis are feasible.
Structure of cryptosporiopsin: a new antibiotic substance produced by a species of Cryptosporiopsis
Authors: Strunz G. M. , Court A. S. , Komlossy J. , Stillwell M. A.
Published: May 2006

The structure of cryptosporiopsin, a novel chlorine-containing antifungal agent produced by a species of Cryptosporiopsis, has been elucidated on the basis of spectral and chemical studies.
Pyrazolines VIII. Migration of a carbomethoxy group in a bromopyrazoline to pyrazole conversion
Authors: McGreer D. E. , Wigfield Y. Y.
Published: May 2006

The stereoisomers of 4-bromo-3-methyl-3-carbomethoxy-1-pyrazoline (1 and 2) have been prepared and are both transformed readily into 3-methyl-4-carbomethoxypyrazole (6). This transformation requires preferential migration of a carbomethoxy group over a methyl group.
Electrochemical methoxylation of vinyl ethers: a novel anodic dimerization reaction
Authors: Belleau B. , Au-Young Y. K.
Published: May 2006

Electrolysis of vinyl ethers in methanol using a platinum anode and nickel cathode was found to yield the corresponding 1,2-dimethoxylation products (60–66%) and products resulting from a tail-to-tail dimerization to succindialdehyde acetals (20–22%). A mechanism involving radical cation intermediates is proposed.
Osmotic and activity coefficients of some simple borates in aqueous solution at 25°
Authors: Platford R. F.
Published: May 2006

Activity coefficients for sodium tetraborate, potassium tetraborate, sodium metaborate, sodium fluoroborate, and orthoboric acid were derived from isopiestic vapor pressure measurements. The osmotic behavior of sodium tetraborate, at concentrations up to its solubility limit, was the same as that of the more soluble potassium salt. The mean activity coefficients of both tetraborates were quite low: 0.355 at 0.1 m; the activity coefficients of sodium metaborate and fluoroborate were less than those of sodium chloride, indicating partial association in solution.The boric acid results were not very reliable because boric acid apparently volatilized during the measurements, but the results obtained indicated that it behaves like a non-electrolyte at all concentrations up to saturation, with an activity coefficient never less than 0.92.
Synthesis of acetylenic diols
Authors: Watanabe Shoji , Suga Kyoichi , Suzuki Toshimitsu
Published: May 2006

Lithium naphthalene reacts with acetylenic carbinol, such as 3-methyl-1-butyn-3-ol or propargyl alcohol, to give the corresponding dilithio compounds. The reaction of these dilithio compounds with various ketones gives the corresponding acetylenic diols in good yield. By the new convenient one-step procedure for chain-lengthening, various acetylenic diols can be prepared from two kinds of ketones and acetylene using lithium naphthalene.
Thermal decomposition of optically active unsymmetrical azoalkanes. (−)-(S)-1,1′-Diphenyl-1-methylazomethane
Authors: Kopecky Karl R. , Gillan Thomas
Published: May 2006

The ratio, (Kc/Kr)cage, of the rate of coupling of the 1-phenylethyl radical with the benzyl radical to the rate of its rotation with respect to the benzyl radical in the solvent cage has been determined for several solvents. The optically pure title compound, (−)-(S)-4, has been prepared and its absolute configuration determined. Thermal decomposition of (−)-(S)-4 yields (−)-(R)-1,2-diphenylpropane, (−)-(R)-9, with partial retention of configuration. The maximum rotation of (−)-(R)-9 has been determined. At 100° in benzene, cyclohexane, chlorobenzene, (all containing ca. 1 M butanethiol) and butanethiol, the cage effects for the decomposition of (±)-4 were found to be 28.3, 31.7, 33.4, and 18.2%, respectively. Under these conditions (−)-(R)-9 was formed from (−)-(S)-4 with 10.3, 10.9, 13.0, and 17.3% net retention of configuration, respectively. A simple expression for (Kc/Kr)cage can be derived:[Formula: see text]F is the fraction of radicals consumed within the solvent cage and f is the fraction of radicals consumed within the solvent cage that disproportionate. Under the above conditions values for (Kc/Kr)cage were found to be 0.059, 0.069, 0.090, and 0.070, respectively. The values of the cage effect and (Kc/Kr)cage given were calculated assuming f = 0.1, but change little if f is assumed to be 0. The relevance of these results to the stereochemistry of the Wittig and Meisenheimer rearrangements and of the decomposition of diacyl peroxides is discussed.
Enzymic deacylation of esterified mono- and disaccharides. 3. The location of acetylated positions in partially acetylated sugars
Authors: Fink A. L. , Hay G. W.
Published: May 2006

not available
Coordination complexes of acetylene diphosphines. II. Diphosphine bridged palladium(II) and platinum(II) derivatives
Authors: Carty A. J. , Efraty A.
Published: May 2006

Complexes of the type (MX2)2(DPPA)2 (M = Pd, Pt; X = Cl, Br, I, SCN; DPPA = bis(diphenylphosphino)acetylene) have been prepared and characterized. Raman, infrared, and molecular weight data have been used to show that the structures are binuclear with bridging bis(diphenylphosphino)acetylene groups. The infrared spectra of the compounds [M(SCN)2]2(DPPA)2 are suggestive of the presence of both N and S bonded thiocyanate within the same molecule.
Crystal structures of potassium, ammonium, rubidium, and cesium tetrafluoborates
Authors: Clark M. J. R. , Lynton H.
Published: May 2006

The crystal structures of potassium, ammonium, and rubidium tetrafluoborates have been redetermined. The structure of cesium tetrafluoborate has also been established. These 4 compounds are isomorphous and show orthorhombic symmetry, space group Pbnm. Atomic parameters have been obtained from a block diagonal least squares refinement using anisotropic temperature parameters. The final agreement residuals for observed reflections were KBF4, R = 0.072; NH4BF4, R = 0.075; RbBF4, R = 0.064; and CsBF4, R = 0.051.There are significant differences between some of the B—F bond distances in the [BF4]− ions. The shortest N—(H)F distance in NH4BF4 is 2.914 Å (estimated standard deviation 0.005 Å) which is long for a hydrogen bond. The positions of the hydrogen atoms in the NH4+ ion could not be established.
Structural studies on the glycolato, lactato, and mandelato solid complexes of some bivalent iron series metals
Authors: Fischinger Andrew , Sarapu Allen , Companion Audrey
Published: May 2006

Electronic absorption spectra, infrared vibrational spectra, and X-ray powder patterns have been measured for anhydrous bis(glycolato), bis(lactato), and bis(mandelato) complexes of bivalent Mn, Co, Ni, Cu, and Zn. Despite indications of considerable differences in crystal structure, the visible spectra of all complexes are quite similar to those of analogous hexaaquo complexes. A ligand field analysis yields as new data a spectrochemical series for the ligands[Formula: see text]in agreement with the order of proposed metal–oxygen stretch frequencies and previously measured acid pK's of the ligands.An interesting red to blue color change, observed in all cobalt complexes on heating, is shown to be reversible in the glycolate. A tentative model proposed for the complex appears to be consistent with all the experimental data including the color change phenomena.
Thermal reactions of O2+ and O− ions in gaseous ammonia
Authors: Bohme D. K. , Fehsenfeld F. C.
Published: May 2006

The reaction channels and rate coefficients for the reactions of O2+ and O− ions with NH3 have been determined at 21.4 °C in a flowing afterglow of pure oxygen and a mixture of helium and oxygen. Charge-transfer was found to be the dominant O2+ reaction channel whereas hydrogen atom abstraction was found to be the dominant O− reaction channel. The secondary NH3+ ions were found to react further with NH3 by hydrogen abstraction to yield NH4+ ions, which readily associated with NH3 to yield cluster ions. The further reaction of secondary OH− ions with NH3 was not observed suggesting that the electron affinity of NH2 may be less than 1.10 eV.
Infrared spectra, rotational correlation functions, band moments, and intermolecular mean squared torques of methane dissolved in liquid noble gases
Authors: Cabana A. , Bardoux R. , Chamberland A.
Published: May 2006

Extensive measurements of the infrared (i.r.) absorption spectra of liquid methane and of methane dissolved in liquid argon, krypton, and xenon have been carried out. Band profiles for the v3 and v4 modes of CH4 and CD4 are reported. From these profiles the rotational correlation functions have been calculated. Comparison of the experimental functions with the functions calculated for the free rotators at the appropriate temperatures reveals that each molecule rotates freely for only 1.3 × 10−13 s before it undergoes a hard collision; the same result was obtained for all the systems investigated. Difficulties in obtaining accurate values of the band moments are discussed and suggestions for overcoming them are presented. Values ranging from 6.9 to 8.2 × 104 cm−2 have been obtained for the mean squared torques acting on methane in the various solutions.
Relaxations of molecular charge distributions and the vibrational force constants in diatomic hydrides
Authors: Bader R. F. W. , Ginsburg J. L.
Published: May 2006

The force constants for LiH, HF, NaH, and HCl are calculated from Hartree–Fock wavefunctions by a polynomial fit of the forces exerted on the nuclei as a function of the internuclear separation. The magnitude of the force constant is interpreted in terms of the relaxation of the molecular charge distribution induced by the nuclear displacement. In LiH or NaH, for which the molecular charge distribution exhibits the characteristics of ionic binding, two distinct relaxations are evident: a relaxation in the region of the cationic core and a relaxation of the density localized on the proton. The relaxation of the charge density in the vicinity of the Li+ or Na+ core opposes the motion of either nucleus while the relaxation of the density localized on the proton facilitates the displacement of the nuclei. In HF or HCl the relaxation of the molecular charge distribution is dominated by one continuous region of charge increase (for bond contraction) or decrease (for bond extension) over the whole of the binding region, a relaxation which facilitates the motion of the nuclei. Thus the relaxation of a molecular charge distribution and its effect in determining the magnitude of the force constant is dominated by the same features of the static charge distribution which serve to distinguish ionic from covalent binding.
Effect of chain length on storage stability and hydrolytic reversion of sodium polyphosphate glasses
Authors: Fuchs Robert J. , Lutz Charles W.
Published: May 2006

At low concentrations in hard water, the polyphosphates revert to orthophosphate at rates which are not predictable from data obtained at higher concentrations. A reversal in the effect of pH on reversion rate at lower concentrations appears to be due to complex formation between the polyphosphate and the hard water metal ions. A minimum in the rate of reversion of polyphosphate glasses to orthophosphate occurs at an average chain length between about 13 and 40 under the low concentration hard water conditions. Phosphate glasses having an average chain length below 30 show good storage stability but longer-chain glasses undergo a decrease in chain length under normal "dry" storage conditions, with the rate of degradation increasing with increasing chain length.
Mechanism of formation of trimethylisoxazole and intermediates upon alkaline hydrolysis of nitroethane
Authors: Lockhart R. W. , Ng K. W. , Nott P. E. , Unrau A. M.
Published: May 2006

Nitroethane and higher homologous primary nitroalkanes undergo a base-catalyzed condensation yielding the corresponding 2,3,4-trialkyisoxazoles. Basic hydrolysis of nitroethane to acetaldehyde is the key initial step followed by a series of condensation and elimination reactions. Through the use of appropriately 14C-labelled intermediates and acetaldehyde-d4, a relatively simple mechanism is indicated which will satisfactorily account for all observed intermediates indicated in a summary of the reaction sequence.[Formula: see text]
Study of the exchange rates of ethanol and water on ferriprotoporphyrin IX by n.m.r. line broadening
Authors: Angerman N. S. , Hasinoff B. B. , Dunford H. B. , Jordan R. B.
Published: May 2006

The nuclear magnetic resonance (n.m.r.) line broadening technique has been used to determine the rate of solvent exchange from the first coordination sphere of ferriprotoporphyrin IX (hemin) in aqueous ethanol. The line broadenings of the methyl and methylene protons of ethanol and the water protons have been studied as a function of solvent composition at 35° and of temperature in 48.8 mole % ethanol.The average values of the kinetic parameters for ethanol molecule exchange, taken from the CH3 and CH2 proton broadening are ΔH≠ = 6.2 ± 1.0 kcal mole−1 and ΔS≠ = −9.1 ± 4.4 cal mole−1 deg−1. Both proton transfer and water molecule exchange contribute to the water proton line broadening with a net value of ΔH≠ = 6.3 ± 0.5 kcal mole−1 and ΔS≠ = −3.8 ± 2.0 cal mole−1 deg−1.From the n.m.r. study at varying solvent composition, it is concluded that monomeric and dimeric hemin undergo solvent exchange at the same rate. The equilibrium constant for formation of the monoethanol solvated hemin from hydroxyhemin is determined as 8.7 at 35° from this study.A comparison of the rate of ethanol exchange (1.8 × 106 s−1 at 25°) and the rate of imidazole binding to hemin (from a separate temperature jump study) indicates that the imidazole substitution occurs through an SN1 ion pair mechanism.
New synthesis of S-alkyl-DL-homocysteines
Authors: Kolenbrander Harold M.
Published: May 2006

A simple method for the synthesis of S-alkyl-DL-homocysteines is described. The method involves the reaction of homocysteine thiolactone with a primary alkyl halide in sodium methoxide solution.
Arrhenius parameters for the reaction of propyl radicals with propane
Authors: Berkley R. E. , Woodall G. N. C. , Strausz O. P. , Gunning H. E.
Published: May 2006

The reaction of n-propyl radicals from the photolysis of azo-n-propane with propane has been studied and Arrhenius parameters for hydrogen atom abstraction relative to the recombination of n-propyl radicals determined. From the Arrhenius parameters obtained and the available thermodynamic data, the Arrhenius parameters of the reverse reaction, the hydrogen atom abstraction from propane by iso-propyl radicals, have been calculated.Some complicating factors in the photolysis of azopropane are discussed.
Etude polarographique des méthoxyhydroperoxydes
Authors: Renard Jean , Fliszár Sándor
Published: May 2006

The polarographic behavior of selected α-methoxyhydroperoxides, produced by ozonization of olefins in methanol, has been studied. A mechanism is proposed for the electrode process. An analytical application for the quantitative determination of these methoxyhydroperoxides and for the study of the mechanism of ozonolysis of unsymmetrical olefins is described.
Constitution of magnesium–indium alloys containing 23–100 atomic % indium
Authors: Pickwick K. M. , Alexander W. A. , Gamble R. H.
Published: May 2006

A constitutional diagram for magnesium–indium alloys containing between 23.2 and 100 atomic % indium has been established using differential thermal analysis, electrical resistivity, and metallographic methods.An intermediate solid solution, β, with a wide range of homogeneity, is formed peritectically from the liquid and α, the magnesium primary solid solution. It extends between 23 atomic % indium at 485.3 °C and 86 atomic % indium at 160.2 °C, where it is in equilibrium with γ, the indium primary solid solution. Magnesium has a limited solid solubility in indium of about 6 atomic %.For alloys containing up to 50 atomic % indium, the derived constitutional diagram is in good agreement with that of a previous investigation (2). Two exceptions are noted: first, there is no evidence of a long period superlattice, β′′′ of the CuAu II type, and second, a reaction is observed involving a transition between the two ordered phases β′ and β′′. For the indium-rich alloys no intermediate or ordered phase formation is observed.The results have been discussed in terms of the existing phase diagrams.
Equisorptic compositions in reverse osmosis
Authors: Kopeček J. , Sourirajan S.
Published: May 2006

The existence of equisorptic solution compositions in reverse osmosis systems is illustrated.
A new method of synthesis of aldosuloses
Authors: Walton D. J.
Published: May 2006

As a new approach to the synthesis of aldosuloses (osones), epimeric pairs of the allylic alcohols, 1 and 2, and 4 and 5, were oxidized to the corresponding vinyl ketones, 3 and 6, respectively. Degradation of the latter by reductive ozonolysis and hydrolysis gave D-glycero-tetrosulose and D-arabino-hexosulose (D-glucosone), respectively.
Permanganate–periodate oxidation. Part VIII. The oxidation of some cyclic mono-olefins and monoterpenes
Authors: Suga T. , Rudloff E. von
Published: May 2006

The reaction of cyclic mono-olefins with the permanganate–periodate reagent was investigated. 4-Terpinenol and its acetate, and to a lesser degree α-terpineol and camphene gave in addition to the expected products, several neutral and acidic products. In contrast, α-pinene, β-pinene, sabinene, pulegone, and several cyclo-olefins which can be considered as simple analogues of these monoterpenes, afforded the predicted products in high yield. Cyclo-hexanone and menthone, though saturated, were oxidized extensively, enolization offering a plausible pathway for this result. Saturated terpene alcohols reacted only very slowly indicating that attack at a tertiary hydrogen is not a significant part of the permanganate–periodate reaction.
A new synthesis of poly-γ-D- and L-glutamic acid
Authors: Kovacs J. , Schmit G. N. , Johnson B. J.
Published: May 2006

A new synthesis of native polyglutamic acid is described through the polycondensation of γ-glutamylglutamic acid-α,α′-di-t-butyl-γ-pentachlorophenyl ester. This route eliminates the possibility of transpeptidation.
Substituent effects in the reaction of aromatic amines and peroxydisulfate
Authors: Venkatasubramanian N. , Sabesan A.
Published: May 2006

The kinetics of the reaction between aromatic amines and the peroxydisulfate ion in aqueous basic conditions have been investigated. The effect of substituents has been studied by employing about 25 ortho-, meta-, and para-substituted anilines. The reaction is accelerated by electron-releasing substituents and is retarded by electron-withdrawing substituents, pointing to an electrophilic attack by the S2O82− ion. A better correlation between rate and the Hammett constants is obtained for an electrophilic attack at the nitrogen atom of the amine rather than at the carbon atom of the amine. A good correlation also exists between the log k2 values and the pKb of the corresponding amines.
Adamantanethione and its reduction to 2-adamantanethiol
Authors: Greidanus J. W. , Schwalm W. J.
Published: May 2006

Reaction of adamantanone with phosphorus pentasulfide affords the corresponding thioketone. This new, comparatively very stable alicyclic thione was also obtained by an indirect route from 2-ethoxy-2-adamantanethiol. Reduction of the thioketone with sodium borohydride yields 2-adamantanethiol.
Studies on the decomposition of tetra-alkylammonium salts in solution. Part II. Dependence of the activation parameters on the structure of the substrate
Authors: Burns J. T. , Leffek K. T.
Published: May 2006

The enthalpy and entropy of activation for the decomposition reaction of seven tetra-alkylammonium iodides in chloroform solution have been measured. All the salts contained the benzyl group attached to the nitrogen atom and decomposed to yield benzyl iodide and a tertiary amine as the only products.A Hammett free energy correlation is made and used to deduce the nature of the transition state, and a rationalization of the variation of the enthalpy and entropy of activation with the structure of the substrate is given.
Absolute rate constants for hydrocarbon autoxidation. XVII. The oxidation of some cyclic ethers
Authors: Howard J. A. , Ingold K. U.
Published: May 2006

The propagation and termination rate constants have been determined for the autoxidation of 1,4-dioxan, tetrahydropyran, tetrahydrofuran, 2,5-dimethyltetrahydrofuran, and phthalan. The rate constants for α-hydrogen atom abstraction from some of the ethers by the tetralylperoxy radical and from tetralin by some ether peroxy radicals have been measured and compared. The chain transfer rate constants have been estimated for the reaction of the cumylperoxy radical with α-hydroperoxytetrahydrofuran, α-hydroperoxytetrahydropyran, and α-ethoxyethyl hydroperoxide.
Infrared spectra and rotational isomerism of mono-, di-, and tri-ethylene glycol monoalkyl ethers
Authors: Srinivasan T. K. K. , Jose C. I. , Biswas A. B.
Published: May 2006

Infrared spectra have been recorded of the following mono-, di-, and tri-ethylene glycol monoalkyl ethers: CnH2n+1OCH2CH2OH where n = 17 and 19; CnH2n+1(OCH2CH2)2OH where n = 17, 18, 19, and 22; and C18H37(OCH2CH2)3OH. Spectra of the pure liquids, solutions in CCl4, and the solids at room and liquid air temperatures have been studied. From a study of the CH2 rocking modes at 927–934, 889, 900, and 862 cm−1 during the liquid–solid transformation and from solution studies, it has been shown that both the OCH2CH2O groups in diethylene glycol monoalkyl ethers exist predominantly in the gauche conformation in liquid and in solution. However, in the solid, while the end OCH2CH2O group takes both trans and gauche forms, the OCH2CH2O group adjacent to the polymethylene chain appears to take a trans configuration. The long polymethylene chain is found to pack in a triclinic subcell in the solid state, while in the quenched liquid state an orthorhombic or monoclinic packing is indicated. The present investigation has led to the conclusion that the difference in the conformations of end CH2CH2CH2OH groups found between the odd and even chain n-alcohols is removed in mono- and diethylene glycol monoalkyl ethers by the introduction of one or two OCH2CH2 groups.
Carbohydrates in alkaline systems. II. Kinetics of the transformation and degradation reactions of cellobiose, cellobiulose, and 4-O-β-D-glucopyranosyl-D-mannose in 1 M sodium hydroxide at 22 °C
Authors: MacLaurin Donald J. , Green John W.
Published: May 2006

Rates of isomerization, epimerization, and degradation reactions were measured for cellobiose (7), cellobiulose (8), and 4-O-β-D-glucopyranosyl-D-mannose (9) at 0.001 M in 1 M NaOH under N2 in the dark at 22 °C. Reaction system resolution was by column chromatography on anion resins in the borate form. Assay for D-glucose (1), D-fructose (2), D-mannose (3), and 7,8, and 9 was by continuous automated colorimetry of column effluent with orcinol–sulfuric acid as reagent. Reaction rate constants (h−1) found: k78 0.078, k79 0.0005, k7,10 0.002, k87 0.022, k89 0.003 k81 0.065, k8,12 0.023, k97 0.002, k98 0.013, k9,11 0.006 where 10,11, and 12 are other products than 1,2,3,7,8, and 9. Details for preparation of 8 and 9 are given.
Polarographic half-wave potentials and ultraviolet absorption spectra of some conjugated heteroenoid compounds
Authors: Holmes H. L. , Currie D. J.
Published: May 2006

The half-wave potentials of phenyl substituted derivatives for each series of conjugated heteroenoid compounds studied follow a Hammett relationship. The effect of change in the functional groups and of increase in length of the conjugated system upon half-wave potentials and ultraviolet absorption maxima is briefly discussed. Terephthalylidene derivatives of active methylene compounds function like the cinnamylidene derivatives.
Metal oxide trialkylsilyloxide polymers. Part V. Further studies on titanium oxide triethylsilyloxide polymers
Authors: Bradley D. C. , Lorimer J. W. , Prevedorou-Demas C.
Published: May 2006

Tetrakis(triethylsilyloxy)titanium, Ti(OSiEt3)4, was hydrolyzed under controlled conditions in dioxane at 60 °C. The soluble initial products [TiOx(OSiEt3)4−2x]n, with x = 0.1–0.5, underwent disproportionation when heated at 65 °C under high vacuum to give Ti(OSiEt3)4 and products with values of x in the range 0.4–1.4. Molecular weights were determined by cryoscopy in cyclohexane, and the linear dependence of 1/n on x was used as a basis for structural proposals. The results are compared with those obtained previously for the initial products of hydrolysis.
An investigation of the structures of the adducts of SF4 with BF3, PF5, AsF5, and SbF5 in the solid state and in solution in HF
Authors: Azeem M. , Brownstein M. , Gillespie R. J.
Published: May 2006

The structure of the solid adducts of SF4 with several fluoride acceptors has been studied by investigations of the 18F exchange between S18F4 and BF3 and between SF4 and B18F4, the infrared spectrum of SF4.BF3, and the Raman spectra of SF4.BF3, SF4.PF5, SF4.AsF5, and SF4.SbF5. The experimental observations are best accounted for in terms of an ionic structure SF3+.MXn− in each case, but there is good evidence for relatively strong fluorine bridging between the ions.In anhydrous hydrogen fluoride solution, SF4 and the adducts SF4.BF3 and SF4.SbF5 were studied conductimetrically and by 19F nuclear magnetic resonance. Both methods indicate complete ionization of the adducts to SF3+ and the complex fluoroanion. SF4 is a weak base in hydrogen fluoride ionizing to SF3+ and HF2−.
Heat capacity of activation for the hydrolysis of methanesulfonyl chloride and benzenesulfonyl chloride in light and heavy water
Authors: Robertson R. E. , Rossall B. , Sugamori S. E. , Treindl L.
Published: May 2006

Rates of solvolysis of methanesulfonyl chloride and benzenesulfonyl chloride have been determined in H2O and D2O. The free energy, enthalpy, entropy, and heat capacity of activation were calculated. The exceptional accuracy of the data permitted an estimation of dΔCp≠/dT from a four parameter temperature dependence of the kinetic rates.From these data we conclude that both sulfonyl chlorides hydrolyse by the same mechanism (Sn2) The change in R from CH3 to C6H5 in RSO2Cl did not alter ΔCp≠ but ΔS≠ (20°) was changed from −8.32 to −13.25 cal deg−1 mole−1, respectively. The significance of this difference is attributed to the probability of bond formation rather than to differences in solvent reorganization.
Cryoscopic studies with molten fluorides. I. Depression of the freezing point of calcium fluoride by alkaline-earth fluorides and oxides and calcium silicates
Authors: Kojima H. , Masson C. R.
Published: May 2006

The depression of the freezing point of CaF2 by BaF2 and MgF2 is ideal in the limit of low concentrations, and excess partial free energies of CaF2 at finite concentrations are in accord with data for other systems. Limiting depressions due to SrF2, CaO, and SrO are each approximately 1/4, and due to BaO and MgO, 1/2, of the ideal values. Calcium orthosilicate behaves ideally on the basis of 1 SiO44− ion per molecule. For calcium metasilicate, the results are interpreted in terms of a distribution of fluorosilicate ions of general formula (SiO3)nF(2n+1)− in the melts. For Ca3SiO5, the depressions are complicated by the nonideal behavior of oxygen ions. From the phase diagrams at low concentrations, CaO behaves ideally in CaCl2, and MgO is ideal in MgF2. The results are discussed in terms of possible formation of solid solutions in some of these systems.
Adducts of oxovanadium(IV) dithiocarbamates
Authors: McCormick B. Jack
Published: May 2006

Pyridine and 4-methylpyridine adducts of oxovanadium(IV) dithiocarbamates have been isolated and characterized as solids. It has been shown that the addenda can be removed under mild conditions with concomitant regeneration of the parent dithiocarbamate (DTC) complexes. Attempts to isolate dimethyl-sulfoxide adducts have not been successful, although spectral evidence suggests that adducts are formed in solution. A qualitative rationalization of the molecular orbital ordering and electronic spectral properties of the adducts is presented.
Absolute configuration of conhydrine
Authors: Fodor G. , Bauerschmidt E. , Craig J. Cymerman
Published: May 2006

Catalytic hydrogenation of optically active 2-pyridyl ethylcarbinol (1) formed the alkaloid conhydrine (2) stereospecifically. Application of the von Braun reaction gave conversion of (+)-conhydrine into R-(−)-3-octyl benzoate and of (−)-conhydrine into the S-(+)-antimer. Both the relative and absolute configuration of the two asymmetric centers in natural (+)-conhydrine have been determined by the combined use of optical rotatory dispersion (o.r.d.) and circular dichroism (c.d.). The results are in agreement with other physical and chemical evidence.
Ring B conformation in 9,10-dihydroanthracenes by nuclear magnetic resonance
Authors: Jimenez F. Garcia , Perezamador M. C. , Alcayde J. R.
Published: May 2006

The nuclear magnetic resonance data of some 9,10-dihydroanthracenes with substituents on the aromatic rings allow the assignment of a pseudoboat conformation for the central ring. The dihedral angle formed by the two planes in the molecule changes according to the substituents.
Spectroscopy of chromium compounds in molten salts
Authors: Brookes H. C. , Flengas S. N.
Published: May 2006

Modifications to the Hitachi Perkin–Elmer 139 ultraviolet–visible spectrophotometer are described which enable absorption spectra of molten salts to be measured to 865 °C. The instrument can be readily reconverted for ambient temperature measurements. The solubilities and the limiting heats of solution of Ag2CrO4 and PbCrO4 in equimolar NaNO3–KNO3 have been measured spectrophotometrically from 250 to 350 °C. The absorption spectrum of dilute solutions of Cr(III) in CsCl has been measured, the octahedral CrCl63− being present in solution at 700 °C.
Reaction of 3-aroylaziridines with diphenylcyclopropenone. Synthesis and properties of novel 4-aroyl-4-oxazolines
Authors: Lown J. W. , Smalley R. K. , Dallas G. , Maloney T. W.
Published: May 2006

3-Aroylaziridines and 3-acylaziridines react with diphenylcyclopropenone with the formation of novel 4-aroyl-4-oxazolines and 4-acyl-4-oxazolines respectively. The unusual physical and chemical properties of these reactive heterocycles are discussed.
Radiolysis of aqueous chloroform solutions
Authors: Rezansoff B. J. , McCallum K. J. , Woods R. J.
Published: May 2006

Saturated aqueous chloroform solutions (0.07 M) with pH ranging from 0.8 to 12.6 have been irradiated with 60Co γ-radiation in the presence and absence of air. G(Cl− + ClO−) increases with increasing pH in the pH range 1–3 (aerated solutions) or 3–6 (deaerated solutions) and again at pH greater than 10.5. The variation in yield from aerated solutions in the region pH 1–3 is attributed to competition between chloroform and hydrogen ions for hydrated electrons. However, such competition cannot account for the pH effect observed in deaerated solutions between pH 3 and 6. Increased yields from both aerated and deaerated solutions at high pH are attributed to the formation of O− by reaction of hydroxyl radicals and hydroxide ions. Formic acid and oxalic acid have been identified as minor products when aerated chloroform solutions are irradiated.
Dipole moments, charge-transfer parameters, and ionization potentials of the methyl-substituted benzene–tetracyanoethylene complexes
Authors: Chan R. K. , Liao S. C.
Published: May 2006

The dipole moments of a series of charge-transfer complexes of methylbenzenes with tetracyano-ethylene in carbon tetrachloride solutions at 25 °C and the various parameters derived from Mulliken's theory have been evaluated. The energies of various states of the complexes were calculated via their relationships with the parameters, charge-transfer transition energies, and heats of formation of the complexes by means of the variation principle. Vertical ionization potentials of the donors were obtained from the calculated energies of the dative structures of the complexes. The dipole moments contributed from the charge-transfer interaction can also be reasonably interpreted as charge-transfer energies in terms of vertical ionization potentials of the donors.
Novel cycloaddition reactions with alkyl substituted nitrogen heterocycles
Authors: Lown J. W. , Westwood R. , Aidoo A. S. K.
Published: May 2006

2-Methylquinoxaline reacted with two molar equivalents of tetrachloro-1,2-benzoquinone to give two products (a) a colored polycyclic heterocycle structurally related to quinoxaline orange and (b) 2-(2-quinoxalino)-4,5,6,7-tetrachlorobenzo-1,3-dioxole. 2,6-Dimethylquinoline, 2-methylquinoline, and 1-methylisoquinoline react with the quinone to give products of type (a) whilst, 2,3-dimethylquinoxaline, 2,3-dibenzylquinoxaline, and 2-benzylpyridine react with the quinone to give products of type (b). Thermal decomposition of 2-quinoxalinylmethyltrimethylammonium hydroxides results in cycloaddition to form the new 5,8,13,16-tetraazadibenz[a,h]anthracene system. Similar thermal decomposition of 2-quinolinylmethyltrimethylammonium hydroxide produced the new 8,16-diazadibenz[a,h]anthracene ring system.
New synthesis of (±)-cyclohexene-1,3/2,4-tetrol (conduritol-B)
Authors: Nagabhushan T. L.
Published: May 2006

1,4,5,6-Tetra-O-acetyl-myoinositol is reacted with N,N′-thiocarbonyl diimidazole to give 1,4,5,6-tetra-O-acetyl-myoinositol-2,3-thionocarbonate. This is desulfurized with trimethyl phosphite to yield tetra-O-acetyl-(±)-cyclohexene-1,3/2,4-tetrol (tetra-O-acetyl-conduritol-B).
Hydrogen bonding in lidocaine salts. I. The stretching band and its dependence on the associated anion
Authors: Neville George A. , Regnier Zephyr R.
Published: May 2006

not available
Heats of formation of some alkylthio radicals
Authors: Fine D. H. , Westmore J. B.
Published: May 2006

From a comparison of the dissociation energies of carbon–oxygen and carbon–sulfur bonds in alcohols, thioalcohols, ethers, and thioethers, a self-consistent set of values for the heats of formation of the methylthio-, ethylthio-, n-butylthio-, iso-butylthio-, sec-butylthio-, t-butylthio-, phenylthio-, and benzylthio-radicals is derived.
Crystal structure of di-p-tolyl mercury
Authors: Mathew M. , Kunchur N. R.
Published: May 2006

Di-p-tolyl mercury crystallizes in space group P21/c with cell constants a = 10.12, b = 5.07, c = 11.65 Å, β = 91.8°, Z = 2. The structure was solved by mercury-phased three-dimensional electron density Fourier synthesis and refined by least-squares. The final R-index was 0.085 for all reflections. The molecule of di-p-tolyl mercury is found to be planar having linear carbon–mercury–carbon bonds. There are no significant intermolecular close approaches, the structure is, therefore, of molecular type.
N-Chlorination of secondary amides. III. Kinetics of dechlorinationof N-chloroamides
Authors: Wayman M. , Thomm E. W. C. W.
Published: May 2006

Several N-chlorinated secondary amides have been dechlorinated in aqueous or aqueous methanol solutions of phenol. The dechlorinating agents were found to be OH− and C6H5O−, with the rate expression [Formula: see text] The substituent groups R1 and R2 of the N-chloroamide [Formula: see text] influence the dechlorination reactions through induction and resonance effects. The reactivity of the N-chloroamides was found to be in the order [Formula: see text] and [Formula: see text]These results are discussed and reaction mechanisms proposed.
Preparation and reactions of triarylsilylmethylmetallic reagents
Authors: Brook A. G. , Duff J. M. , Anderson D. G.
Published: May 2006

Triarylsilylmethylmetallic reagents have been prepared by several routes: metalation; addition of phenyllithium to vinyltriphenylsilane; direct synthesis; and by halogen–metal exchange. The latter method is highly superior as regards both generality of application and yields. Dibromomethylsilanes undergo halogen-metal exchange at −78°, and reaction of the product with hydrogen bromide serves as a valuable way of converting geminal dibromides to monobromides. The organometallic reagents have been characterized in several ways, in particular by carbonation to give the related carboxylic acid.
Competitive chlorination reactions with ICl. II. CH4, C2H6, C3H8, and C2H5Cl
Authors: Kelly Carol C. , Yu W. H. S. , Wijnen M. H. J.
Published: May 2006

The H atom abstraction from CH4, C2H6, C3H8, and C2H5Cl by Cl atoms produced by photolysis of ICl in daylight has been studied. Relative rates for the abstractions from CH4, C2H6, primary and secondary hydrogens from propane, and for the abstraction from the CH3 and CH2Cl sides of C2H5Cl have been obtained at room temperature. These data are compared with other literature values.
Thermal decomposition of cyclopentene
Authors: Mackay G. I. , March R. E.
Published: May 2006

The thermal decomposition of cyclopentene, which had previously been shown to proceed by a gas-phase homogeneous process, has been found to be accelerated in the presence of glass wool fibers. The roles of products in the lowering of the overall rate in the later stages of decomposition have been investigated.
Supersonic molecular beam intensities
Authors: LeRoy Rodney L. , Govers Thomas R. , Deckers Jacques M.
Published: May 2006

This paper attempts to obtain agreement between theoretical and experimental supersonic molecular beam intensities. Measurements of absolute beam intensities are presented, corrected for the effect of background scattering in the expansion chamber. It is found that these intensities are considerably lower than those predicted by existing theories. This is true even when losses due to imperfect skimming are negligible. A new mechanism is therefore proposed which postulates a considerable attenuation of the beam due to "self-scattering" collisions upstream of the skimmer and downstream of the onset of translational freezing. Using this mechanism it is possible to reasonably reproduce the experimental intensities.
Free radicals by mass spectrometry. XLIL Ionization potentials and ionic heats of formation for C1—C4 alkyl radicals
Authors: Lossing F. P. , Semeluk G. P.
Published: May 2006

Ionization potentials for C1—C4 alkyl free radicals have been re-measured by electron impact, using an energy-resolved electron beam from a double-hemispherical electrostatic monochromator. From these values and kinetic data for heats of formation of the radicals, ionic heats of formation for C1—C4 alkyl ions have been calculated. New values for the four isomeric butyl ions are given. The ionization efficiency curves for the simpler radicals show linear sections corresponding to excitation of vibrational levels; for larger radicals these segments are not resolved and only a smooth upward curvature is seen. In disagreement with earlier results, no evidence for formation of low-lying excited states of the ions could be found, either for parent or fragment ions.