bluuebunny/crossref_metadata_2025 huggingface dataset:
Infrared absorption of HCl and HBr in solid nitrogen. Evidence for rotation in a nitrogen matrix
Authors: Harvey K. B. , Shurvell H. F.
Published: May 2006

The infrared absorption of HCl and HBr in solid nitrogen at liquid helium temperatures has been recorded. Multiplets have been observed in the region of the fundamental of each molecule. An interpretation is given, based on rotation of the HCl and HBr molecules in the nitrogen matrix.
The hydrogenation of methylacetylene. II. The reaction of methylacetylene with hydrogen catalyzed by nickel, iron, and cobalt
Authors: Mann R. S. , Khulbe K. C.
Published: May 2006

The reaction between methylacetylene and hydrogen over unsupported nickel, iron, and cobalt catalyst has been investigated in a static constant volume system for a wide range of temperature and reactant ratios. The reaction over metals is largely simple hydrogenation, the early stages being principally a selective production of propylene with small yields of reduced polymers of methylacetylene. The orders of the hydrogenation were first and zero to slightly negative with respect to hydrogen and methylacetylene. The overall apparent activation energies for nickel, iron, and cobalt were 12.2, 8.1, and 7.3 kcal/mole respectively. Selectivity was highest with iron and least with nickel.
Mercury-photosensitized decomposition of dimethyl ether. Part I. Mechanism
Authors: Loucks L. F , Laidler K. J
Published: May 2006

The mercury-photosensitized decomposition of dimethyl ether was investigated from 200 to 300 °C and over the pressure range 3 to 600 mm Hg. Measurements were made of the initial rates of formation of the products of reaction, which are CO, H2, C2H6, CH4, CH3OC2H5, and CH3OCH2CH2OCH3. It is concluded that the primary step involves a C—H split; there is no evidence for a primary C—O split. Over the range 200 to 300 °C the methoxymethyl radical, CH3OCH2, decomposed to give formaldehyde and a methyl radical, whereas at 30 °C no decomposition of the CH3OCH2 radical was detected. The mass balance is consistent with the mechanism proposed. The homogeneity of the reaction conditions was examined by varying the concentration of mercury in the reaction vessel.
Solubility of p-dimethylaminobenzaldehyde in aqueous solutions of HCl and H2SO4 at 25.00 °C
Authors: Gamble Donald S.
Published: May 2006

The solubility of p-dimethylaminobenzaldehyde (DABH) in aqueous HCl and aqueous H2SO4 solutions has been measured at 25.00 °C. The concentration ranges of HCl and H2SO4 were 0.01 m to 1 m, and 0.005 m to 0.5 m respectively. The equilibrium constants for solubility in H2O and for protonation of the dimethylamino group are 0.604 × 10−2 m (±0.5%) and 43. m−1 (±2.4%) respectively. Sufficiently concentrated acid solutions of this aldehyde are treated as mixed electrolytes owing to the extensive protonation of the tertiary amino group. Cation molal activity coefficient ratios (γdabh/γh+) for the tertiary ammonium and H+ ions have been calculated.
Spectrophotometric studies on surfactants. II. Infrared study of adsorption from solutions of single and mixed surfactants, on copper substrates
Authors: Scowen R. V. , Leja J.
Published: May 2006

Adsorption studies were carried out from solutions of alkyl dithiocarbormtes (xanthates) or alkyl carboxylates and from mixtures of these anionic species with cationic alkyl trimethyl ammonium bromides (CnTAB). The substrates consisted of polished copper plates in three states of oxidation, i.e. either with a thick oxide coating left after polishing, a thin oxide residue left after acid etching, or an adsorbed layer of oxygen formed on vacuum deposition of copper film.The infrared reflectance spectra of the copper plates have indicated that the nature of the adsorbed species is not limited to a single constituent. In adsorption of lauric acid, either cupric laurate, laurate ion, or a mixture of the two species can be detected in the spectra of the adsorbed coatings. The degree of hydroxylation of copper surface and the degree of ionization of the adsorbate appear to be governed by the pH at the copper/liquid interface and not by the pH in the bulk of solution; in turn, the interfacial pH is determined by the amount of copper oxide present initially at the solid surface and undergoing dissolution during treatment with the solution of adsorbate.Adsorption from mixtures of sodium laurate and CnTAB was found to depend on the relative chain lengths; C12TAB yielded a precipitate containing laurate ion and lauric acid, together with C12TA ion, and resulted in slowing the adsorption (as cupric laurate); on the other hand, C18TAB kept laurate ions in mixed micelles which completely prevented adsorption of either component on copper substrates.In solutions of alkyl xanthates, cuprous xanthate was the main product of adsorption, with dixanthogen coadsorbing mainly when short chain xanthates (i.e. ethyl) were used. With mixed solutions, no coadsorption of CnTAB was detected, but the rate of xanthate adsorption was increased severalfold; in addition, complexed xanthate−CnTAB species were capable of adsorbing under conditions when uncomplexed xanthate ion did not adsorb (i.e. when free oxygen and oxide layers were excluded from the system).
Reaction of active nitrogen with oxygen
Authors: Vlastaras A. S. , Winkler C. A.
Published: May 2006

The maximum yields of oxygen atoms, estimated at different levels in a long-tube reactor by gas-phase "titration" with NO2, were equal for the reactions of active nitrogen with NO and O2. In this reactor, the maximum oxygen-atom production from the oxygen reaction, determined by the amount of N2O3 produced with excess NO2, was found to correspond to the NO "titration" value for the active nitrogen and not to the maximum amount of HCN produced in the active nitrogen – ethylene reaction. A second-order rate constant,

[Formula: see text]

[Formula: see text]was obtained for the active nitrogen – oxygen reaction.Experiments in a short reactor showed that the validity of the analytical method based on the trapping of N2O3 depended upon adequate reaction time for the NO + NO2 reaction to occur.
The infrared spectra of theobromine salts
Authors: Cook Denys , Regnier Zephyr R.
Published: May 2006

From the infrared spectra of theobromine salts it is concluded that the salts are probably arranged in hydrogen-bonded centrosymmetric pairs involving

[Formula: see text] interactions.

[Formula: see text] anion− hydrogen bonds are formed by protonation of the free nitrogen atom (N9) in the imidazole ring. Infrared absorption bands arising from the former hydrogen bond constantly appear near 3 000 cm−1, whereas those from the latter shift from 2 580 to 3 300 cm−1, depending on the anion. In-plane NH and N+H deformation modes give bands near 1 485 and 1 160 cm−1, respectively. Out-of-plane NH modes have been located, but precise assignments are not possible.The assignments for some other bands which show deuteration shifts are detailed, and the carbonyl stretching vibrations which increase in frequency on protonation of the free base are identified.
Thiazolo[3·2-a]benzimidazoles
Authors: Alper Anne E. , Taurins A.
Published: May 2006

Thiazolo[3·2-a]benzimidazole (I) and several of its derivatives were synthesized by annelation of the thiazole ring to a benzimidazole. The intermediate 3-hydroxy-2,3-dihydrothiazolo[3·2-a] benzimidazoles were identified and the 3-position of the hydroxyl group was established by oxidation to 3-(2H)-thiazolo[3·2-a]benzimidazolone. Tautomerism of the 3-hydroxy-2,3-dihydrothiazolo[3·2-a]benzimidazoles was also investigated.3-Hydroxy-2,3-dihydrothiazolo[3·2-a]benzimidazole and the corresponding 3-methyl compound were found to undergo nitrogen acetylation and rearrangement under acetylating conditions.
Pyrolysis gas chromatography of some hydrocarbons
Authors: Sutton Russell , Harris W. E.
Published: May 2006

The variables important to the development of pyrolysis gas chromatography as a means of identification of liquids and gases were studied by placing a pyrolysis tube at the inlet of a gas chromatographic column. The pyrolysis conditions can be controlled to limit the formation of methane and to yield the maximum quantities of other products for identification of the parent compounds. Conditions that reduce methane formation are the absence of air, low temperatures, a long residence time, and the use of quartz rather than stainless-steel pyrolysis tubes. There is a limited range of pyrolysis temperatures that permits the formation and observation of all products in a pyrogram.
Calculation of kinetic isotope effects in formation of carbon dioxide from a diester of oxalic acid
Authors: Warkentin J. , Singleton D. M.
Published: May 2006

Equations for the calculation of isotope effects (k12/k13 and k16/k18) in the concerted twobond thermolysis of oxalates are presented. The equations are developed for material of low isotopic abundance such that the presence of doubly labelled molecules can be ignored. No assumption is made about the distribution of 18O between the carbonyl and ether functions, other than that the distribution is known. The experimental data required are the ratios CO246/CO244, and CO245/CO244, corrected for the presence of 17O and 14C, in the CO2 obtained from partial decomposition and in the CO2 from total decomposition and the fractional extent of reaction.
Ion lifetimes in gaseous radiolysis systems
Authors: Wood C. J. , Back R. A. , Dawes D. H.
Published: May 2006

A technique is described for measuring ion lifetimes in irradiated gases. Gases were irradiated continuously, and lifetimes were determined by measuring average ion currents, obtained with an intermittent square-wave applied field, as a function of square-wave period. The dose rates, pressures, and vessel geometry were similar to those commonly used in radiolysis experiments, so that the information obtained can be applied directly to an understanding of radiolysis mechanisms. The theory of the method and analysis of ion-loss processes are discussed in some detail.Measurements in oxygen at pressures from 30 to 300 Torr and dose rates from 1.5 to 56 × 1010 eV cc−1 s−1 gave mean ion lifetimes ranging from 0.014 to 0.082 s. The dependence of lifetime on dose rate and pressure indicated that ion loss under these conditions was almost entirely by gas-phase combination. Values of α, the gas-phase combination coefficient, are compared with those measured by other methods.
Ion–molecule reactions in gaseous methyl amine
Authors: Jones E. G. , Harrison A. G.
Published: May 2006

The ion–molecule reactions in gaseous methyl amine have been studied. The following reactions have been identified and their rate coefficients (all in cm3 molecule−1 s−1 units) determined for ions of 3.4 eV ion exit energy.

[Formula: see text]Reactions [a] and [c] were also studied at thermal ion energies and little variation of the rate coefficients with ion energy was found in contrast with theoretical predictions.
H-atom scrambling and cis–trans isomerization of dideuteroethylene photosensitized by several organic compounds
Authors: Hirokami Shun-Ichi , Sato Shin
Published: May 2006

H-atom scrambling and cis–trans isomerization of dideuteroethylene have been observed with various photosensitizers: benzene, toluene, p-xylene, o-xylene, m-xylene, mesitylene, fluorobenzene, and benzotrifluoride. The pressure dependences are satisfactorily explained in terms of the two excited state mechanism previously proposed.Using Kassel's equation for the rate of unimolecular reactions, the energies of the triplet states of the sensitizers have been estimated. The values obtained coincide with the spectroscopic values.
Hydrogen bonding and conformation in cis- and trans-2-alkoxy-3-hydroxytetrahydrofurans
Authors: Zajac Jr. W. W. , Sweet F. , Brown R. K.
Published: May 2006

Infrared spectra show both free and hydrogen bonded hydroxyl absorption in several trans-2-alkoxy-3-hydroxytetrahydrofurans. The extent of non-bonded hydroxyl is greater than that of bonded hydroxyl. Suggestions are made of possible conformations which might account for the infrared data.
Reactions of nitro sugars. VII. A study on acetylation and some chemical properties of acetates
Authors: Baer Hans H. , Kienzle Frank , Rajabalee Farouk
Published: May 2006

The 2,4,6-tri-O-acetates of methyl 3-deoxy-3-nitro-β-D-glucopyranoside, -galactopyranoside, and-mannopyranoside, the 2-O-acetates of the 4,6-O-benzylidene derivatives of the two first-mentioned glycosides, and the tetra-O-acetate of 1,4-dideoxy-1,4-dinitro-neo-inositol are prepared by boron trifluoride–catalyzed acetylation. The advantages of the procedure over acetylation in pyridine are pointed out. The gluco triacetate, when produced in the presence of pyridine, is accompanied by crystalline by-products of a novel nature. It suffers undetermined changes by the action of activated alumina, and in dilute aqueous alkali it is instantly converted into an unsaturated nitronate.
Two-step synthesis of cis,cis-1,6-cyclodecadiene
Authors: Sharma S. N. , Srivastava R. K. , Devaprabhakara D.
Published: May 2006

A convenient synthesis of cis,cis-1,6-cyclodecadiene (3) has been described starting from cis,cis-1,5-cyclononadiene (1). This two-step sequence involves the synthesis of 1,2,6-cyclodecatriene (2) in one-step followed by chemical reduction with sodium and liquid ammonia.
γ-Radiolysis of cyclohexane with electron scavengers. III. Perfluorocarbons as electron scavengers
Authors: Sagert N. H.
Published: May 2006

The room temperature, liquid phase radiolysis of cyclohexane in the presence of three solutes, per fluorocyclohexane (PCH), perfluoromethylcyclohexane (PMCH), and perfluorocyclobutane (PCB) has been examined. All decrease the hydrogen yield from 5.6 to 2.6 G units by capturing electrons. However, with PMCH and PCB the yields of cyclohexene and bicyclohexyl are not decreased as much as the hydrogen yield and with PCH, dimer and olefin yields are increased. Furthermore, large yields of monohydrofluorocarbon (e.g. undecafluorocyclohexane) are produced, indicating that a carbon–fluorine bond has been broken. It is concluded that electron capture by these fluorocarbon compounds causes dissociation; possible mechanisms are discussed, but it was not possible to reach a clear conclusion on the basis of our results.The radiolysis of homogeneous solid solutions of these solutes at 77 °K has also been studied, but only PMCH was studied in detail. Under these conditions there is no evidence for dissociative electron capture and apparently the combination of solute anion and hydrocarbon cation on warming does not lead to bond breaking.
Nature of the coordination bond in metal complexes of substituted pyridine derivatives. I. The substituent effect on the coordination bond
Authors: Wong Patrick T. T. , Brewer D. G.
Published: May 2006

The nature of the coordination bond in some metal complexes of 4-substituted pyridines has been investigated by thermodynamic and infrared spectroscopic methods. The effects of the substituents upon the coordination bond strength in the copper(II) complexes of these ligands have been found by direct measurement of the heats of coordination. These effects have been further described by the substituent effect upon the change in free energy of the coordination center in the ligands. A new parameter, Rπ, measuring the relative π bonding in the complexes of 4-substituted pyridines has been introduced. For this purpose a series of complexes of the types [M(4—R—C5H4N)2Cl2] and [(4—R—C5H4N)•HCl] (R = CH3, CH2OH, H, COCH3, CONH2, COOCH3, CN; M = Cu(II), Zn(II)) has been isolated, and the infrared spectra of these complexes and the free ligands have been examined.
Pyrolysis of phenylmercaptoacetic acid
Authors: Tan A. T. C. H. , Sehon A. H.
Published: May 2006

The pyrolysis of phenylmercaptoacetic acid was investigated by the toluene-carrier technique over the temperature range 760–835 °K. The main products of the decomposition were phenyl mercaptan, carbon dioxide, acetic acid, phenyl methyl sulfide, carbon monoxide, and dibenzyl.The overall decomposition was a first-order reaction with respect to phenylmercaptoacetic acid and could be represented by the two parallel steps:[Formula: see text]Reaction [1] was shown to be a homogeneous first-order dissociation process, and its rate constant was represented by the expression[Formula: see text]The activation energy of this reaction, i.e. 58 kcal/mole, was identified with D(C6H5S—CH2COOH).
Intermolecular fluorine exchange between tetrabutylammonium hexafluorophosphate and BF3 or PF5
Authors: Brownstein S. , Bornais J.
Published: May 2006

A rapid exchange of fluorine between hexafluorophosphate ion and BF3 or PF5 in methylene chloride solution has been found to occur by a bimolecular mechanism. The exchange rates were determined by fluorine magnetic resonance spectroscopy and the apparent Arrhenius activation energies were obtained.
Potentiometric and conductometric studies on the composition and stability of zinc complexes of thiomalic acid
Authors: Saxena R. S. , Gupta K. C. , Mittal M. L.
Published: May 2006

The precise nature of the reaction between zinc and thiomalic acid in aqueous 0.1 M KNO3 has been investigated potentiometrically and conductometrically. The formation of two complexes, one predominating at pH 5.5–7 and another at pH 8–9.5, was found. The stability constants of the complexes formed have been determined by applying Calvin and Melchior's extension of Bjerrum's method at three different temperatures. The log K values for 1:1 and 1:2 complexes computed by alternative methods at 25, 30, and 35 °C have been found to be 8.75, 8.85, 8.86, and 6.82, 6.75, 6.93, respectively. The values of the overall changes in ΔG, ΔH, and ΔS accompanying the reaction have also been evaluated at 30 °C and found to be −21.61 kcal/mole, −5.3 kcal/mole, and +53.8 cal/deg respectively.
Erratum: Radiation chemical data in water using nitrous oxide
Authors: Head D. A. , Walker D. C.
Published: May 2006

not available
Reinvestigation of the Polonovski reaction. Synthesis of deuterated dimethylamine and formaldehyde
Authors: Renaud R. N. , Leitch L. C.
Published: May 2006

Dimethylaminomethyl acetate, a postulated intermediate in the Polonovski reaction, has been isolated for the first time in 80% yield from the reaction between trimethylamine N-oxide and one equivalent of acetic anhydride. With more acetic anhydride the dimethylaminomethyl ester gave N,N-dimethyl acetamide and two other products which have been identified as 2-(dimethylaminornethyl)acrylic acid and 2,2-bis(acetoxymethyl)-3-(dimethylamino)propionic acid. The manner of formation of these two products has been clarified by using deuterium and 13C labelled reagents.Hydrolysis of deuterated dimethylaminomethyl acetate prepared from trimethyl-d9 amine N-oxide and acetic anhydride gave satisfactory yields of dimethyl-d6 amine and formaldehyde-d2.
Synthesis and chemistry of 1-methyl-3-hydroxy-3-phenyl-6-chloro-1,2,3,4-tetrahydroquinoline-2,4-dione
Authors: Podesva C. , Solomon C. , Vagi K.
Published: May 2006

Treatment of 2-(N-methyl)-dichloroacetamido-5-chlorobenzophenone with an aqueous-alcoholic solution of sodium acetate yields 1-methyl-3-hydroxy-3-phenyl-6-chloro-1,2,3,4-tetrahydroquinoline-2,4-dione. Some transformation products of this compound are described.
Two general intermediates for the synthesis of anhydropenicillins
Authors: Wolfe Saul
Published: May 2006

A procedure is given for the preparation of the hydrated potassium salt of 6-N-tritylaminopenicillanic acid (1). Conversion of 1 to the acid chloride followed by treatment with triethylamine produced the anhydro derivative 2. Reaction of 2 with p-toluenesulfonic acid monohydrate gave the p-toluenesulfonic acid salt 3 of anhydro 6-aminopenicillanic acid. The free base 4 was generated with sodium bicarbonate; acylation with phenylacetic acid by the carbodiimide method afforded anhydropenicillin G.
Fluoranthene studies. III. A synthesis of 3-bromo-6-nitrofluorenone
Authors: Charlesworth E. H. , Mathiaparanam P.
Published: May 2006

A synthesis of 3-bromo-6-nitrofluorenone has been accomplished by the diazotization and Pschorr cyclization of 2-amino-4-bromo-4′-nitrobenzophenone, the synthesis of which is described. The identity of the above bromonitrofluorenone with the degradative oxidation product of 9-bromo-2-nitrofluoranthene establishes unequivocally the structure of the latter substance.
Properties of the solutions of the alkali-chlorozirconate compounds in alkali-chloride melts
Authors: Flengas S. N. , Dutrizac J. E. , Lister R. L.
Published: May 2006

The activities of Li2ZrCl6, Na2ZrCl6, and K2ZrCl6 in the systems LiCl–Li2ZrCl6, NaCl–Na2ZrCl6, and KCl–K2ZrCl6, respectively, were calculated from available pressure data using a modified form of the Gibbs–Duhem relationship. The calculations indicate positive deviations from ideality that decrease with increasing size of the alkali metal cation.
High field kinetic processes in anodic oxide films on aluminium. II. Current transients for constant field conditions
Authors: Dignam M. J. , Ryan P. J.
Published: May 2006

Anodic oxide films were formed on high purity aluminium (99.996%) in a glycol–borate electrolyte. Following aging of the films under zero field conditions either at room temperature or 60 °C the electrodes were returned to the electrolysis cell where the anodic overpotential was increased rapidly until a predetermined value was reached, then maintained constant. The ensuing current transients were recorded and analyzed. As little film growth occurred during these measurements the conditions correspond closely to constant field strength. For sufficiently low field strengths the observed current decreased monotonically with increasing time. No single empirical equation could be found to represent these data, although they appear to be in the nature of charging currents rather than ion currents. For somewhat higher applied fields the current is observed to decrease initially, reach a minimum, and then increase approaching ultimately the steady-state ion current for the applied field strength. These data can be accounted for satisfactorily by only the polarization theory of ionic current transients.
Tellurium isotope fractionation study
Authors: Smithers R. M. , Krouse H. R.
Published: May 2006

"Normal vibration equations" have been solved to yield vibrational frequencies for isotopic compounds of tellurium. These frequencies were used to evaluate "partition function ratios" for 122Te- and 130Te-containing compounds. Theoretical "isotopic equilibrium exchange constants" and estimates of "kinetic isotope effects" were derived from these ratios. The results suggest that the 122Te/130Te abundance may be altered significantly in laboratory reactions and terrestrial processes.Preliminary experiments have realized kinetic isotope effects of 0.7 and 0.6% in inorganic and microbiological reductions respectively of tellurite to elemental tellurium. These results are interpreted in terms of the isotope effect in Te—O bond breakage.The maximum variation in the 130Te/122Te abundance ratio of six natural tellurides and two commercial preparations of TeO32− was found to be 0.4%.The results are compared with those found in analogous selenium and sulfur isotope investigations.
Radiolysis of n-hexenes
Authors: Brash J. L. , Golub M. A.
Published: May 2006

The radiolysis of hexene-1, hexene-2, and hexene-3 at room temperature was studied with particular emphasis on the mechanisms leading to dimer formation. The structures of the hexene dimers were investigated by means of infrared and n.m.r. spectroscopy. The dimers from hexene-1, -2, and -3 had average unsaturations of 1.0, 1.2, and 1.2 double bonds/molecule, respectively, and were formed with G values of 4.6, 4.6, and 4.1 respectively. The dimerization of hexene-1 could be interpreted as proceeding, in part, through an ionic mechanism leading exclusively to monoolefinic structures, and in part through another ionic mechanism leading to a mixture of saturated, monoolefinic, and diolefinic structures. Hexene-2 and hexene-3 were found not to dimerize by the first of these ionic mechanisms, but largely by the second mechanism, along with some contribution from an exclusively radical process. The hexene-1 results are in qualitative accord with those previously reported for this olefin, while the differences noted here between this terminal olefin and the nonterminal olefins, hexene-2 and hexene-3, are qualitatively similar to the differences reported previously for butene-1 and butene-2.
Crystal structure of β-Cu2P2O7
Authors: Robertson B. E. , Calvo C.
Published: May 2006

The crystal structure of β-CU2P2O7 has been determined by X-ray methods. The crystals are monoclinic with a = 6.827(8) Å, b = 8.118(10) Å, c = 4.576(6) Å, β = 108.85(10)°, Z = 2, and space group C2/m. This structure is analogous to that of the mineral thortveitite and the high temperature forms of the pyrophosphates of Zn, Mg, and Mn. The cations are octahedrally coordinated to oxygen atoms with equatorial Cu—O bonds of 2.00 Å and 1.94 Å while the axial bond lengths are 2.58 Å. The anion has inner P—O bonds of 1.542 Å and average terminal bonds of 1.509 Å. In addition to the usual refinement with anisotropic thermal parameters, the structure has been refined in terms of a disordered structure generated from the low temperature α form of CU2P2O7. This disordered model agrees as well with the data (R = 0.12) as the structure based on the thortveitite structure with large anisotropic motion assigned to the atoms.
Hydrogenation of methylacetylene. III. The reaction of methylacetylene with hydrogen catalyzed by nickel, copper, and their alloys
Authors: Mann R. S. , Khulbe K. C.
Published: May 2006

The reaction between methylacetylene and hydrogen over unsupported nickel, copper, and their alloys has been investigated in a static constant volume system between 20 and 220 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and nearly independent of temperature. While the order of reaction with respect to methylacetylene over nickel catalyst was slightly negative and temperature dependent, it was always positive and nearly independent of temperature for copper and copper-rich alloys. Selectivity was independent of initial hydrogen pressure for nickel and copper only; for others it decreased rapidly with increasing hydrogen pressure. The overall activation energy varied between 9 and 21.2 kcal/g mole. Selectivity and extent of polymerization increased with increasing amount of copper in the alloy.
Line-width effects in the electron spin resonance spectra of ion-pairs of 2,3- and 2,5-dimethyl-p-benzosemiquinones
Authors: Gill P. S. , Gough T. E.
Published: May 2006

Electron spin resonance spectra of ion-pairs of 2,3- and 2,5-dimethyl-p-benzosemiquinone are reported. Numerical relationships between the various splitting constants suggest the equality of QC–Mc and QC–H. Unexpected sharp lines in the spectra recorded under conditions of line-width alternation are interpreted in terms of these numerical relationships.
Phenolysis of 1-menthyl borate
Authors: Lalancette J.-M. , Beauregard Y.
Published: May 2006

The phenolysis of 1-menthyl borate has been made by a variety of phenols, the kinetics of the reaction being followed by polarimetry. The behavior of the system can be related to the acidity of the phenol. With phenols of pKa < 10.0, the course of the reaction indicates a phenolysis proceeding normally towards an equilibrium. With phenols of pKa > 10.0, the rotatory power of the reaction mixture increases and in the case of phenols of [Formula: see text] an intermediate type of curves is obtained. Hydrolysis and solvent effects are reported.
Co-extraction of phosphoric and tetrachloroferric acids
Authors: McCorkell Robert H. , Irvine Jr. John W.
Published: May 2006

The presence of an extracting strong acid greatly enhances the extraction of phosphoric acid from aqueous solutions into organic solvents, but no type of compound forms between the phosphoric acid and the other extracted species. Only the alteration of the solvent properties when an ionic species and water are added to it can account for the increase in [Formula: see text]
Erratum: γ-Radiolysis of cyclohexane with electron scavengers. IV. CO2 as an electron scavenger
Authors: Sagert N. H.
Published: May 2006

not available
Methods for the synthesis of L-lactyl-L-valine-1-14C
Authors: Slater G. P. , Spencer H.
Published: May 2006

The preparation of L-lactyl-L-valine from L-lactic acid and L-valine, by methods used for the synthesis of peptides, was investigated. Initial experiments with O-benzoyl-DL-lactic acid and DL-valine benzyl ester unexpectedly gave N-benzoyl-DL-valine benzyl ester. However, coupling between O-benzyloxycarbonyl-DL-lactic acid and either DL-valine, or DL-valine benzyl ester, occurred in good yield. A simpler method, which was reported to give a 39% yield of L-lactyl-L-valine, gave only 10% of product but was modified to give L-lactyl-L-valine-1-14C in 90% yield.
Steroids and related products. XXV. Cardiotonic steroids. II. The synthesis of 17β-substituted 14(15)-unsaturated steroids of the A/B-cis series. Part I
Authors: Bach G. , Capitaine J. , Engel Ch. R.
Published: May 2006

The synthesis, from smilagenin, progesterone, and pregnenolone, of Δ14-3β-hydroxy-5β-etienic acid and some of its ester derivatives, as well as of β-anhydrodigitoxigenin acetate, is described. Since these 14-unsaturated products have served as starting materials for our previously published syntheses of 3β,14β-dihydroxy-5β-etianic acid and of digitoxigenin, the present work establishes that these 17β-substituted 14β-hydroxylated products are available from readily accessible materials and that the syntheses of these 14β-hydroxylated products must be regarded, from a formal point of view, as total syntheses. We have thus elaborated a general pathway from common steroids—also available by total synthesis—to 14β-hydroxylated derivatives, in particular to steroid cardiotonics.
Spirocyclic tetrahydropyrimidines derived from pentaerythritol
Authors: Salvador Romano L. , Saucier Michel
Published: May 2006

A series of seven spirocyclic compounds bearing the newly synthesized 6,8-diaza-2-oxaspiro[3•5]nonane ring system are reported. Their preparation consists in the condensation of 3,3-bis(aminomethyl)oxetane monohydrate, obtained via pentaerythritol tribromide and, 3,3-bis(bromomethyl)oxetane, with certain amidines and guanidines.
Etude quantitative des réactions d'ozonolyse. VI. Sur la réduction du zwitterion de Criegee en composé carbonylé
Authors: Fliszár S. , Chylińska J. B.
Published: May 2006

It is shown for a series of symmetric olefins that ca. 44 % of the zwitterion which does not react to give ozonide yields open-chain peroxides. The latter, when formed of [Formula: see text] units, decompose rapidly into aldehyde and O2 (at room temperature), whereas such polymeric peroxides are relatively stable at 25° in CCl4 when built of ketonic carbonyloxides.
The molecular structure of ryanodol-p-bromo benzyl ether
Authors: Srivastava Surendra Nath , Przybylska Maria
Published: May 2006

The molecular structure of ryanodol-p-bromo benzyl ether was solved without any chemical assumptions, using three dimensional data obtained by the heavy atom technique. It was found to be identical with the structure proposed by Dr. K. Wiesner, except that the configuration was reversed at one carbon atom. The refinement of atomic parameters with a least-squares method is still in progress. The R factor is at present 0.12.
Dielectric studies. Part XVIII. Dipole moments and relaxation times of some symmetrically substituted alkylbenzenes
Authors: Crossley J. , Walker S.
Published: May 2006

The dielectric absorption at four microwave frequencies of pure liquid benzene and p-cymene at 25 °C, p-xylene and mesitylene at 25, 40, 50, and 60 °C, and solutions of durene and hexamethylbenzene in mesitylene at 60 °C has been examined. All show measurable loss factors and apparent dipole moments of about 0.1 to 0.2 D. These moments are less in magnitude than those associated with the short relaxation time (τ2) process for the polar monoalkylbenzenes. o-xylene and m-xylene. Their relaxation times are too short for molecular reorientation and there is a rough correlation between the number of collisions/molecule s and the reciprocal relaxation time.
Ultrasonic study of hydrochloric acid association in N,N-dimethylformamide
Authors: Chan Siu C. , Valleau J. P.
Published: May 2006

Ultrasonic absorption and velocity have been measured in anhydrous N,N-dimethylformamide solutions of hydrogen chloride, over the frequency range 13 to 143 mc/s, and the concentration range 0.05 M to 3.5 M. A large relaxation is observed and ascribed to the association of the acid. The rate constants for this reaction are obtained, and their variations with concentration are discussed. The association rate appears to be entirely diffusion controlled, and the corresponding "reaction distance" is large. This may be related to the very large effect on the sound velocity (and hence on the compressibility) that arises from the introduction of these ions.
Beryllium and scandium electrode potentials in fused LiCl–KCl eutectic
Authors: Plambeck James A.
Published: May 2006

Electrode potentials of the Be(II)–Be(0) and Sc(III)–Sc(0) systems were measured in dilute solutions of the ionic species in fused LiCl–KCl eutectic at 450 °C. Standard molar electrode potentials of these couples of −2.039 ± 0.013 V and −2.553 ± 0.015 V against a standard molar platinum reference were calculated. It was shown by voltammetric and chronopotentiometric methods that the equilibrium [Formula: see text] suggested by previous authors was not significant in this medium.
Le volume libre dans les liquides
Authors: Godbout Germain , Sicotte Yvon
Published: May 2006

not available
Some aspects of cis–trans-isomerization mechanisms
Authors: Lin M. C. , Laidler K. J.
Published: May 2006

It is shown that there is a linear relationship between the activation energy for a thermal cis–trans isomerization and the heat of hydrogenation of the C=C bond. There is also a linear relationship between the entropy of activation and the heat of activation, there being a partial compensation effect. It is pointed out that the activation energy for these processes is very close to the π-bond energy of the C=C bond. The significance of these relationships is discussed in terms of the reaction mechanisms.
Pyrolysis of HNCO vapor
Authors: Back R. A. , Childs J.
Published: May 2006

The pyrolysis of HNCO vapor has been studied briefly at pressures from 5 to 20 Torr and temperatures from 550 to 700 °C. Products observed were CO, N2, H2, CO2, HCN, and C2N2; the elemental balance suggests that NH3 and NH2CN may also have been products. The pyrolysis is complicated by surface effects, polymerization, and secondary reactions, and is not amenable to quantitative kinetic studies.
Electron spin resonance studies of radiation damage. Part I. An alternating linewidth effect for the (CH3)2ĊOH radical in gamma-irradiated acetone at low temperatures
Authors: Sargent F. P.
Published: May 2006

The e.s.r. spectrum of the (CH3)2ĊOH radical showed a drastic temperature dependence of linewidth in the range −196 to −100 °C, this being particularly pronounced for the M1 = ±2 lines. Possible mechanisms are discussed in terms of restricted rotation of the methyl groups and of the OH groups.
Quenching of hexafluoroacetone phosphorescence by mercury
Authors: Lang N. C. , Kutschke K. O.
Published: May 2006

The ratio of the relative yield for fluorescence to that for phosphorescence of hexafluoroacetone excited at 3130 Å was measured; the ratio was a linear function of mercury concentration. This observation confirms that the deactivation of the triplet state proceeds by a reaction which is first order in [Hg]. A quenching constant was obtained which is in excellent agreement with that based on lifetime measurements under mercury-free and mercury-saturated conditions.
Deuterated amino acids. IV. The synthesis of L-phenyl d5-alanine-2,3,3-d3
Authors: Blomquist A. T. , Cedergren R. J.
Published: May 2006

The synthesis of L-phenyl-d5-alanine-2,3,3-d3 is described. The synthetic route involved the enzymatic deacylation of acetylphenyl-d5-alanine-2,3,3-d3, which was obtained by catalytic reduction (deuteriumation) of the hydrolyzed 2-methyl oxazolone derivative of benzaldehyde-d6. The ultraviolet, infrared, and optical rotatory dispersion spectra of L-phenylalanine-d8 are reported along with some corresponding data on the deuterated intermediates.
Concerning the mechanism of the addition of ethanesulfenyl chloride to 3,4-dihydro-2H-pyran
Authors: Baldwin M. J. , Brown R. K.
Published: May 2006

The nuclear magnetic resonance spectrum, at −40°, of the crude mixture obtained by the reaction of ethanesulfenyl chloride with 3,4-dihydro-2H-pyran at −40° clearly supports the view that the product is trans-2-chloro-3-ethylthiotetrahydropyran. The possibility that there is initial formation of 3-chloro-2-ethylthiotetrahydropyran followed by its rapid rearrangement to 2-chloro-3-ethylthiotetrahydropyran is ruled out because of the stability of 3-chloro-2-ethylthiotetrahydropyran to distillation under vacuum. The latter compound is obtained as a mixture of cis and trans isomers by the reaction of ethyl mercaptan with 5-chloro-3,4-dihydro-2H-pyran in the presence of sulfur dioxide.
Nucleosides. XLIX. Nuclear magnetic resonance studies of 2′-and 3′-halogeno nucleosides. The conformations of 2′-deoxy-2′-fluorouridine and 3′-deoxy-3′-fluoro-β-D-arabinofuranosyluracil
Authors: Cushley Robert J. , Codington John F. , Fox Jack J.
Published: May 2006

Nuclear magnetic resonance data for a series of 2′-halogeno and 3′-halogeno pyrimidine nucleosides are presented. Using a combination of proton–proton and proton–fluorine couplings vs. dihedral angle values 2′-deoxy-2′-fluorouridine is proposed to have an envelope conformation with C–3′ endo, and 1-(3-deoxy-3-fluoro-β-D-arabinofuranosyl)uracil proposed to have a twist conformation with O-ring endo and C–1′ exo. Correlations between substituent electronegativity and both vicinal coupling constants and internal chemical shifts are discussed.Syntheses of several new 2′-halogeno and 3′-halogeno nucleosides are described.
Chemistry of diarylazoalkanes. I. Synthesis of p,p′-disubstituted azocumenes and their decomposition products
Authors: Shelton J. Reid , Gormish Joseph F. , Liang Chih Kuo , Samuel Patricia Lyons , Kovacic Peter , Haynes Leroy W.
Published: May 2006

p,p′-Disubstituted azocumenes were prepared from the requisite p-substituted cumylamines, p-XC6H4C(CH3)2NH2, X = CH3, CH3CH2, (CH3)2CH, (CH3)3C, or Br, by treatment with iodine pentafluoride. The major products from thermal decomposition were dicumyls, along with minor amounts of cumenes and α-methylstyrenes. Syntheses of the corresponding authentic materials are described.
Preparation and structure of dimethyl-α-conidendrin-8-sulfonamide
Authors: Barton G. M.
Published: May 2006

The synthesis and structure of a new derivative of α-conidendrin, an extractive from western hemlock (Tsuga heterophylla [Raf.] Sarg.), are described. Elemental analyses together with high resolution nuclear magnetic spectroscopy enabled the structure to be designated as 2-naphthoic acid, 1,2,3,4-tetrahydro-3-hydroxymethyl-6,7-dimethoxy-4-(3′,4′-dimethoxyphenyl)-8-sulfonamide γ-lactone.
Effects of electron scavengers in the radiolysis of water vapor
Authors: Dixon R. S. , Bailey M. G.
Published: May 2006

Water vapor irradiated with X-rays in the presence of nitrous oxide gives mainly nitrogen and oxygen together with small amounts of hydrogen and, possibly, hydrogen peroxide. The yield of nitrogen, G(N2) = 3.0 ± 0.3, is constant over a wide range of conditions and G(O2) = 1.6 ± 0.3 after an induction period. The hydrogen yield is constant at low doses with G(H2) = 0.45 ± 0.1, but reaches a steady state at higher doses. The nitrogen yield is equated with the yield of scavengeable electrons in water vapor, the value g(e) = 3.0 ± 0.3 being in reasonable agreement with the theoretical value based on W(H2O) = 30 eV. Addition of other electron scavengers to water vapor containing nitrous oxide suppresses the nitrogen yield by competing efficiently for electrons. On the basis of their efficiency in suppressing the nitrogen yield, limiting values for the relative rates of reaction of N2O, SF6, CCl4, and HCl with electrons in water vapor are obtained and comparisons are made with their known electron attachment cross sections in the gas phase.
Studies on the decomposition of tetra-alkylammonium salts in solution. Part I. Phenylbenzylmethylallylammonium iodide
Authors: Leffek K. T. , Tsao F. H.-C.
Published: May 2006

The loss of optical activity from phenylbenzylmethylallylammonium iodide in chloroform solution has been found to be entirely due to decomposition; racemization as such does not take place. The products are benzyl iodide and allylmethylaniline. A mechanism involving decomposition via a triple ion is deduced from the reaction kinetics. The activation parameters (ΔH≠ and ΔS≠) and a secondary deuterium isotope effect are reported.
Spectrophotometric determination of traces of nickel as dithio-oxalate complex
Authors: Ujihira Y. , Roy J. C.
Published: May 2006

The reaction between nickel and potassium dithio-oxalate has been developed into a simple, quick, and precise method for the spectrophotometric determination of traces of nickel and has been applied to the analysis of this element in our studies on its electrodeposition on thin metallized plastic films. On making absorption measurements of the colored compound formed by the reaction in various bases and acids at different concentrations, it was found that a dilute sulfuric acid solution is a good medium for preparation of samples and making the measurements. Maximum absorption of the compounds occurs at 500 mμ and obeys the Beer–Lambert law over a suitable range. The effect of various ions on the determination of nickel by the method has been measured along with the absorption curves of the compounds formed by the reaction of potassium dithio-oxalate with cobalt and copper. The relative merits of the method are discussed with reference to other methods of analysis of traces of nickel.
Hg(3P1) photosensitized reactions of cyclopropane
Authors: Strausz O. P. , Kozak P. J. , Woodall G. N. C. , Sherwood A. G. , Gunning H. E.
Published: May 2006

Under static conditions the major reaction product is a polymer. Polymerization is inhibited by free radical scavengers such as NO, O2, butadiene-1,3, etc. with a simultaneous large increase in propylene yields. The NO inhibited reaction affords propenaldoxime and acrylonitrile as principal products, indicating the presence of allyl radicals, and N2O which is indicative of H atoms. Polymerization can also be suppressed by rapid flow: it is entirely a secondary process. The products of the flow experiments are: propylene, biallyl, allylcyclopropane, 4-methyl pentene-1, hexene-1, 2,3-dimethyl butane, C5 and C9 hydrocarbons, H2, CH4, C3H8, and traces of bicyclopropyl. Most of the products can be accounted for by the self-scavenging of H atoms by propylene and the ensuing reactions of isopropyl and allyl radicals. The major primary step is the formation of an electronically excited cyclopropane, possibly the ground state triplet of trimethylene with a large excess of vibrational energy. The primary decomposition is retarded by pressure. Φ(decomp.) > 0.38, at 20 Torr, but is less than unity.
Chemisorption sites on porous silica glass and on mixed-oxide catalysts
Authors: Cant N. W. , Little L. H.
Published: May 2006

It has been shown previously that two types of adsorption sites exist on the surface of porous silica glass (Corning code no. 7930) for the adsorption of polar molecules, such as ammonia. One site is the surface hydroxyl group which forms a hydrogen bond to the adsorbate molecule. The second type of site is provided by traces of foreign oxides on the glass surface.In the present study, the infrared spectrum of ammonia adsorbed on the silica glass has been compared with that of ammonia adsorbed on samples prepared by adding B2O3, ZrO2, and Al2O3 to a pure silica powder. This comparison suggests that surface boron atoms (a Lewis acid) are the adsorption sites for ammonia on the porous silica glass. An additional type of site (a Bronsted acid or a different type of Lewis acid site, such as aluminium atoms) may exist in small concentrations on the glass and be responsible for isomerization and polymerization reactions with olefins.
Chemistry of phosphorus pentaselenide. I. Its reaction with alcohols
Authors: Kudchadker Mohan V. , Zingaro Ralph A. , Irgolic Kurt J.
Published: May 2006

The reaction of phosphorus pentaselenide with a number of alcohols has been studied. The predicted products, the dialkyldiselenophosphoric acids, were unstable. Derivatives were isolated as the potassium salts or as the chromium(III) complexes. When the salts of the acids were not isolated from the reaction mixture, different derivatives having bridged selenium atoms, viz. (RO)4P2Se4 and (RO)4P2Se5, were isolated. The properties of these compounds as measured using infrared, ultraviolet, n.m.r. spectroscopic and differential thermal analytical methods are reported.
Vacuum ultraviolet chemiluminescence from the reactions of active nitrogen with I2, IBr, ICI, and ICN
Authors: Phillips L. F.
Published: May 2006

Numerous emission lines from excited I, Br, and Cl atoms have been observed between 1261 and 2062 Å. For the flames with I2, IBr, and ICl it is possible to assign excitation mechanisms on the basis of the dependence of emission intensity on either [N] or [N]2. In the case of dependence on [N] the emission is the result of energy transfer from an excited nitrogen molecule, which is produced by reaction of N with NI, has an energy of 185 ± 3.5 kcal/mole, and is identified with the predicted 3Δu species. The dissociation energy of NI is found to lie between 35.6 and 40 + 3.5 kcal/mole. It is proposed that excited nitrogen molecules can be produced as well as removed very rapidly by processes of the type[Formula: see text]
The mechanism of isomerization of cyclopropanes
Authors: Crawford Robert J. , Lynch Thomas R.
Published: May 2006

The racemization rate of trans-(−)-1,2-diphenylcyclopropane has been observed to be greater than that of trans–cis isomerization, in support of a trimethylene intermediate.
Formation et stabilité de complexes hydroxo–ammonio en solution aqueuse. I. Complexes de zinc
Authors: Gubeli A. O. , Ste-Marie J.
Published: May 2006

A new method has been developed for the calculation of the formation constants of complexes in equilibrium with a precipitate in aqueous solution. This has been applied to the study of ammonio and ammonio–hydroxo complexes of zinc in the presence of the hydroxide. The curves of solubility vs. pH and pNH3 tot have been established by means of 65Zn at 25 °C and ionic strength 1.0 with NaClO4.
The chlorosulfuric acid solvent system. Part I. Electrical conductivity, transport number, and density measurements on solutions of simple bases
Authors: Robinson E. A. , Ciruna J. A.
Published: May 2006

Electrical conductivity, transport number, and density measurements on solutions of some simple bases, including alkali metal and alkaline earth metal chlorosulfates, are reported in the chlorosulfuric acid solvent system. The SO3Cl− ion was found to have a high mobility compared with, for example, the mobilities of the alkali metal and alkaline earth metal cations, and is believed to conduct by an abnormal Grotthus-type chain mechanism. Alkali metal chlorosulfates appear to behave as fully dissociated electrolytes, whereas alkaline earth metal chlorosulfates are incompletely dissociated. Difficulties encountered in preparing pure chlorosulfuric acid are discussed.