bluuebunny/crossref_metadata_2025 huggingface dataset:
SOME CONSIDERATIONS ON THE ROLE OF PROTON TUNNELING IN CERTAIN CHARGE TRANSFER PROCESSES
Authors: Conway B. E.
Published: May 2006

Quantum mechanical tunneling of H atoms in certain reactions can have a rate comparable with that of the corresponding classical reaction. Proton tunneling appears to be the mechanism of proton transport in ice. Further studies of this mechanism have been made by determination of the a-c. and d-c. conductance of D2O (and H2O) ice under rigorous conditions of purification. Pre-electrolysis techniques have been applied to the ultrapurification of the D2O and H2O used for the conductance determinations. Isotopic ratios of conductance in solid H2O and D2O are obtained and discussed in terms of the mechanism of H+ or D+ transport in the solid and liquid substances. The theory of proton tunneling previously given is improved by using a quantal distribution function in the calculation of tunneling rates and better agreement with experiment is then obtained. The theoretical isotopic ratio of conductances by the tunneling mechanism in the ices is similar to that found experimentally and smaller than that predicted classically.Since the proton tunneling theory is quantitatively successful in the case of conductance of ice, its examination for other electrochemical processes involving H is necessary. A favorable case for investigation is the electrochemical hydrogen evolution reaction for which the barrier height for tunneling can be varied. Tunneling probabilities are calculated for proton and deuteron discharge at mercury from acid solutions using the theory of Eckart. At intermediate overpotentials the Tafel equation is still obeyed; at low overpotentials a linear current–potential relation is found as in the classical theory. H/D separation factors are calculated for the tunneling mechanism and it is shown that at intermediate and high overpotentials, tunneling leads to values of the separation factor comparable with those deduced classically. Only at low electrochemical rates of H or D production are high separation factors predicted. The tunneling mechanism, however, is distinguishable from the classical mechanism by a new criterion: the Tafel slopes for the tunneling process would be considerably larger (0.2–0.3) than those arising classically (0.12) for a simple discharge mechanism assuming a symmetry factor of 0.5. It is concluded that in certain cases proton tunneling may occur simultaneously with the classical reaction in electrochemical proton discharge and lead to anomalous Tafel 'b' values which are sometimes observed experimentally.
SOME ABNORMAL HYDROGEN ELECTRODE REACTIONS
Authors: Ives D. J. G.
Published: May 2006

A brief account is given of experiments in which gold electrodes, as a result of thermal deactivation in hydrogen, change from a state in which their behavior in relation to the hydrogen evolution reaction is normal to a state characterized by high positive rest potentials, greatly enhanced overpotentials which increase progressively during current flow, and which decay slowly on open circuit, generating potential–time curves which resemble desorption isotherms.Conclusions based on these phenomena are supported by the results of experiments with poisoned platinum electrodes, which not only behave similarly but are also shown to retain reducing power for a limited time on open circuit.It is suggested that electrodeposited hydrogen atoms may sometimes evaporate from an electrode into solution by a mechanism involving the participation of molecule-ions. A recent theoretical treatment of hydrogen overpotential can be extended to allow for the occurrence of such a final reaction step.
TRANSPORT OF HYDROGEN THROUGH PALLADIUM-CLAD ELECTRODES
Authors: Schuldiner Sigmund , Hoare James P.
Published: May 2006

Electrochemical polarization studies of the transport of hydrogen through Pd, Pt, Pd-clad Pt, Au, Ni, and Fe were conducted under conditions of a concentration gradient of either atoms or protons. Transport of hydrogen through an atom concentration gradient was found for Pd and Pd-clad Fe only. Under a proton concentration gradient, protons migrated readily through Pd, but their transfer through Pt was immeasurable unless the Pt was sandwiched between Pd. Transfer of protons through Fe sandwiched between Pd was also found. Hydrogen atoms evidently did not dissolve to a significant extent in Pt, but if protons are introduced from Pd-clad to Pt they can, under the proper conditions, migrate through Pt. The solution and diffusion of hydrogen atoms and also the migration of protons occurred in Fe. Transport of hydrogen, in any form, through Au and Ni was not detected. Considering the electronic configuration of these metals, it was reasonable that proton migration through Au was negligible; however, it was surprising that protons did not migrate through Ni. Reasons for this anomaly are suggested.
THE INFLUENCE OF SURFACE ACTIVE ANIONS ON THE ELECTROREDUCTION OF THE PERSULPHATE ANION AT NEGATIVE POTENTIALS
Authors: Frumkin A. , Nikolajeva-Fedorovich N. , Ivanova R.
Published: May 2006

not available
THE ANODIC PASSIVATION OF IRON
Authors: Snavely Jr. Earl S. , Hackerman Norman
Published: May 2006

A study was made of the anodic passivation of iron in solutions of 0.1 M sodium sulphate at a pH of 3.0. A mass balance of iron equivalent to coulombs required for passivation and iron found in solution after passivation showed that approximately 0.002 coulomb/cm2 is involved in the passive layer. À Flade arrest does not appear in decay traces of anodic potential unless a potential of at least 1.2 v (EH) is achieved on charging the electrode, indicating incomplete coverage by the passive layer below 1.2 v. Partial cathodic reduction followed by anodic reformation of the passive layer at the Flade arrest showed that the first charging current involved in reformation is highly efficient even when as much as 70% of the Flade arrest is reduced. These results support the view that only a fraction of the passive layer is represented by coulombs involved in the Flade arrest and that after partial reduction the remainder of the passive layer disintegrates spontaneously. Addition of chelating agents to the electrolyte has an adverse effect on passivation by chelation of ferrous ion.
THERMODYNAMICS OF ADSORPTION IN IONIC SYSTEMS
Authors: Parsons Roger
Published: May 2006

not available
ω-HALOALKYL AND ω -AMINOALKYL SULPHIDES CLEAVAGE OF THE ALKYL–SULPHUR BOND
Authors: Kulka Marshall
Published: May 2006

In the homologous series of p-chlorophenyl ω-chloroalkyl sulphides (I), the first and second members reacted abnormally with amines to yield 1, ω-bis(p-chlorophenylmercapto)alkanes (II). The fourth member of the series reacted normally to produce 4-aminobutyl p-chlorophenyl sulphide (III). The formation of II is explained on the basis of an alkyl–sulphur bond cleavage. The members of the p-chlorobenzyl series (VI) in general reacted with amines to form the expected aminoalkyl sulphides (VII). However, the p-chlorobenzyl chloroalkyl sulphides (VI) were thermally labile and decomposed to p-chlorobenzyl chloride and a sulphur component. A cyclic sulphur component originated from VI whose chloroalkyl carbon chain was 4, 5, or 6. The thermal degradation of VI is explained through a sulphonium salt cleavage
THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART II. THE EFFECT OF SOLVENT–SOLUTE INTERACTIONS ON THE INTERMOLECULAR: HYDROGEN BOND IN BENZOIC ACIDS
Authors: Forbes W. F. , Knight A. R.
Published: May 2006

The concentration dependence of some electronic absorption bands, which has previously been ascribed to intermolecular hydrogen bonding, is reinvestigated. The concentration dependences are compared for a number of substituted benzoic acids in inert solvents, and in solvent mixtures containing various amounts of ether. The results are discussed in terms of current theories of hydrogen bonding.
THE QUENCHING OF POTASSIUM RESONANCE RADIATION BY HYDROCARBONS
Authors: Cherniak E. A. , Smith W. M.
Published: May 2006

The quenching of the resonance radiation of potassium by some unsaturated and saturated hydrocarbons has been examined at 67 °C. The behavior was found to be almost identical with that previously observed with sodium, the saturated hydrocarbons quenching to a negligible extent, the unsaturated hydrocarbons exhibiting cross sections with potassium not significantly different from those exhibited towards sodium.
THE INFRARED SPECTRA OF SOME CYCLIC MALONATES
Authors: Abramovitch R. A.
Published: May 2006

The infrared spectra of isopropylidene malonate and some of its derivatives have been examined and compared with those of open-chain malonate esters and of 5,5-dimethylcyclohexane-1,3-dione. Two bands in the carbonyl stretching region are attributed to vibrational coupling of the carbonyl groups in the cyclic esters. There is no evidence that isopropylidene malonate exists in the enolic form either in the solid state or in chloroform solution. This cyclic ester structure for "Meldrum's acid" is thus confirmed.
CO-ORDINATION COMPOUNDS OF NICKEL(II): PART I. THE SPECTRA OF SALICYLALDIMINE DERIVATIVES OF NICKEL(II) IN SOME ORGANIC SOLVENTS
Authors: Clark H. C. , O'Brien R. J.
Published: May 2006

Measurements of the ultraviolet and visible absorption spectra of bis-N-methyl-salicylaldimine nickel(II) and its 5-chloro and 5-bromo derivatives in benzene, chloroform, carbon tetrachloride, and cyclohexane solutions at temperatures between 15° and 45 °C are reported. The results confirm the occurrence of a temperature dependent equilibrium between dia- and para-magnetic forms. The nature of the paramagnetic form is discussed in terms of the recent developments of the ligand field theory. The effect on the equilibrium of substitution of chlorine or bromine in the five position of the salicylaldehyde molecule is also discussed.
THE REACTIVITY OF CELLULOSE: III. THE NITRATION OF COTTON LINTERS ALTERNATELY WETTED WITH WATER AT VARIOUS TEMPERATURES AND DRIED, AND THE PROBABLE DISTRIBUTION OF THE NITRATE GROUPS
Authors: Yin T. P. , Brown R. K.
Published: May 2006

Cotton linters alternately wetted at 0° or 25° and dried show progressively greater ease of nitration paralleling the number of wetting–drying cycles. The reverse is found to be true for linters wetted at 50°, 75°, or 100°. Analysis of the data obtained from lead tetraacetate oxidation of the nitrates favors the depressive concept of nitration and indicates that the observed changes in reactivity occasioned by the wetting–drying treatments are largely due to greater alterations in the accessibility of the primary rather than the secondary hydroxyl groups.
THE KINETICS OF THE EVOLUTION AND DISSOLUTION OF HYDROGEN AT ELECTRODES
Authors: Bockris J. O'M. , Mauser H.
Published: May 2006

not available
ISOLATION OF OLIGOSACCHARIDES IN IMPROVED YIELD BY THE ENZYMATIC DEGRADATION OF POLYSACCHARIDES
Authors: Painter T. J.
Published: May 2006

not available
5-O-β-D-GALACTOFURANOSYL-D-GALACTOSE FROM GALACTOCARALOSE
Authors: Gorin P. A. J. , Spencer J. F. T.
Published: May 2006

not available
THE CONDENSATION OF 1-PHENYL-2-PROPANONE WITH AROMATIC ALDEHYDES
Authors: Abramovitch R. A. , Obach A.
Published: May 2006

not available
A PROPOSED STRUCTURE FOR CHLOROPHYLL d
Authors: Holt A. S. , Morley H. V.
Published: May 2006

Treatment of chlorophyll a or methyl chlorophyllide a with potassium permanganate effected oxidation of the 2-vinyl group without concomitant oxidation of the cyclopentanone ring. One of the products obtained was of especial interest because its visible absorption spectrum was identical with that of a previously known, but chemically uncharacterized, pigment—chlorophyll d. The preparation and identification of this oxidation product as 2-desvinyl-2-formyl-chlorophyll-a is given and its probable identity with chlorophyll d is discussed in detail.
THE DEHYDRATION OF UREA, BENZAMIDE, AND PHENYLUREA BY THIONYL CHLORIDE IN THE PRESENCE OF AMMONIA
Authors: Gagnon Paul E. , Boivin Jean L. , Dickson John H.
Published: May 2006

The decomposition of thionyl chloride in the presence of ammonia was found to give sulphur, ammonium sulphate, and ammonium sulphamate besides ammonium chloride. Heating urea and the reaction products of thionyl chloride and ammonia under pressure yielded guanidine hydrochloride and melamine, under different conditions of temperature, time, and pressure. Under similar conditions, benzamide was transformed into benzonitrile, and phenylurea into aniline or aniline black and diphenylurea, guanidine being absent.
DIALKYL PHOSPHOROISOTHIOCYANATIDATES
Authors: Kulka Marshall
Published: May 2006

An improved method for the preparation of dialkyl phosphoroisothiocyanatidates (II) is given. These compounds (II) are labile and decompose under the influence of heat and catalysts to the corresponding alkyl thiocyanates (III). In the presence of water they hydrolyze to dialkyl hydrogenphosphates (VI) in high yield. A series of thiourea derivatives (VII) has been prepared from II and amines.
REACTIONS OF OXYGEN ACTIVATED BY ELECTRICAL DISCHARGE WITH BUTENE-1
Authors: Jarvie J. M. S. , Cvetanović R. J.
Published: May 2006

Reactions of oxygen activated by electrical discharge with butene-1 have been studied in a "spherical diffusion" reaction zone. When small concentrations of oxygen are passed through the discharge tube in helium as the carrier gas, and the concentration of butene-1 in the reaction zone is sufficiently high, the observed products are entirely explainable by an interaction of the ground-state oxygen atoms with butene-1. With large deviations from these conditions considerable complexities arise, and under some conditions α-butylene ozonide and its decomposition products become important and the products are then explainable without any significant participation of oxygen atoms in the process.
THE ADSORPTION OF HYDROGEN ON RUTHENIUM–ALUMINA
Authors: Low M. J. D. , Taylor H. A.
Published: May 2006

The rate of adsorption of hydrogen on Ru–Al2O3 has been studied at four temperatures from 100 to 257 °C at pressures from 15 to 80 cm DBP. The Elovich parameters α and a for these data have been calculated and their temperature and pressure dependencies found. It is shown that, regardless of temperature, the amount adsorbed at a given time and the parameters α and log aα show a dependence on the initial pressure which is different above and below 25 cm DBP indicating different types of adsorption. The temperature dependencies yield an energy of activation for the initial rate of the high pressure chemisorption of 17.7 kcal mole−1 which is independent of the pressure. Similar E values below 25 cm increase with a decrease in pressure. Four runs showed a very slow nitrogen adsorption on the same surface, raising the question of an enhancement of the adsorption of one gas by traces of another.
VIBRATIONAL SPECTRA OF NAPHTHALENE-d0, -α-d4, AND -d8 MOLECULES
Authors: Mitra S. S. , Bernstein H. J.
Published: May 2006

The infrared and Raman spectra of the naphthalene-α-d4 molecule have been obtained. The spectra of the d0 molecule have also been repeated and for the most part previous measurements have been confirmed. Together with the literature data for the naphthalene-d8 molecule, a complete assignment has been presented for all three molecules. It is recognized that the assignment is not definitive, although satisfactory agreement with the requirements of the band polarizations and contours, as well as product and sum rules, has been obtained. The calculated and observed values for the heat capacity and entropy are also in good agreement.
THE CHARACTERIZATION OF TRI-O-TOSYL SUCROSE
Authors: Bragg P. D. , Jones J. K. N.
Published: May 2006

Tri-O-tosyl sucrose was synthesized by the action of p-tolylsulphonyl chloride upon sucrose in pyridine, and the tosyl groups were shown by methylation to be mainly (84%) located on the three primary hydroxyl groups.
MASS SPECTROMETRIC STUDY OF THE REACTIONS OF SOME HYDROCARBONS WITH ACTIVE NITROGEN
Authors: Herron John T. , Franklin J. L. , Bradt Paul
Published: May 2006

The reactions of active nitrogen with acetylene, ethylene, and propylene have been studied in a flow system using a mass spectrometer to analyze the products continuously. Certain features of the mass spectra of the products can be explained on the basis of cyano radical replacement reactions.
THE BROMINATION OF URACIL AND THYMINE DERIVATIVES
Authors: Moore A. M. , Anderson Shena M.
Published: May 2006

The bromination of 1,3-dimethyluracil, uracil, and thymine and of the nucleosides and nucleotides of the latter two compounds has been followed potentiometrically and spectrophotometrically. The results indicate that all the compounds except uracil react initially with 1 mole of bromine to form 5-bromo-6-hydroxy-hydropyrimidine derivatives. If the resulting compound still has a hydrogen at position 5 it may undergo dehydration on heating or with acid catalysis to form the corresponding 5-bromopyrimidine, which is then capable of further reaction with bromine. Uracil itself appears first to undergo substitution to 5-bromouracil, and then both the uracil and 5-bromouracil are brominated together to yield ultimately 5,5-dibromo-6-hydroxyhydrouracil.
PRESSURE AND TEMPERATURE EFFECTS ON THE KINETICS OF THE ALKALINE FADING OF ORGANIC DYES IN AQUEOUS SOLUTION
Authors: Chen David T. Y. , Laidler Keith J.
Published: May 2006

The rates of the alkaline fading of bromphenol blue, phenolphthalein, crystal violet, and malachite green have been studied from atmospheric pressure to 16,000 pounds per square inch. The rates for phenolphthalein and malachite green were also measured over a range of temperatures in order to determine the activation energies and entropies. The reactions went essentially to completion with the exception of the fading of phenolphthalein, for which the effects of temperature and pressure on the back reaction and equilibrium constant were also studied. No effect of pressure was found for the fading of crystal violet, but the reactions of the other three dyes were accelerated by pressure, so that there are negative volumes of activation. These are correlated with the entropies of activation and are interpreted in terms of the reaction mechanisms.
SOME OBSERVATIONS ON THE THEORY OF DIELECTRIC RELAXATION IN ASSOCIATED LIQUIDS
Authors: Conway B. E.
Published: May 2006

The theory of absolute reaction rates is examined for the case of relaxation in associated polar liquids where the activation process is probably an excitation of a librational motion to one of complete rotation over a rotational potential energy barrier. The rotational barriers in water are calculated using the point-charge model of the water quadrupole and the effect of thermal bond bending is examined. The experimental heats of activation for dielectric relaxation in water and deuterium oxide are discussed and their temperature dependence examined; the heat capacity change for rotational activation is derived. Isotopic effects in the heats of activation, the relaxation times, and frequency factors are discussed. A qualitative explanation is sought for the homogeneity of relaxation times in water; rotation of water molecules in the fields of the hydroxonium and hydroxide ions present in water may account for the narrow distribution of relaxation times observed experimentally. This mechanism is shown to be consistent with other theoretically derived quantities and with the mechanism of proton mobility in water. A different mechanism is indicated in ice, where the proton concentration is lower, but in ice containing extra protons, the mechanism probably reverts to that existing in water.
ELECTRON SPIN RESONANCE ABSORPTION SPECTRUM OF PUMMERER'S OXYGEN RADICAL
Authors: Farmer J. B. , Matsunaga Y. , McDowell C. A.
Published: May 2006

not available
THE REACTIONS OF ACTIVE NITROGEN WITH ACETYLENE, METHYLACETYLENE, AND DIMETHYLACETYLENE
Authors: Schavo A. , Winkler C. A.
Published: May 2006

Hydrogen cyanide was the main nitrogen-containing product of all three reactions, but whereas only about one-half the available active nitrogen was converted to product in the acetylene reaction, the conversion by methyl- and dimethyl-acetylene was substantially complete. A faster-than-linear increase of HCN production with acetylene flow rate was observed at low flow rates. Similar behavior was just perceptible in the corresponding curve for methylacetylene, while no observable inflection was present with dimethylacetylene. Polymer formation was pronounced with acetylene, less so with methylacetylene, and practically absent with dimethylacetylene. Small amounts of cyanogen resulted from all three reactions, while condensable hydrocarbons were obtained in significant yields from the methyl- and dimethyl-acetylene reactions only at higher flow rates of the alkynes.
SOME YIELDS IN THERMAL NEUTRON FISSION OF U233 AND Pu239
Authors: Bartholomew Rosalie M. , Martin J. S. , Baerg A. P.
Published: May 2006

Relative yields of Sr89, Sr91, Ba139, Ba140, and La141 have been measured for U233 and Pu239 thermal neutron fission. Ion exchange separations and 4π beta-counting methods were used. The following relative values were obtained for the nuclides as listed: 1.05, 1.00, 1.00, 1, and 1.10 in U233 fission and 0.301, 0.431, 1.07, 1, and 1.01 in Pu239 fission.
THE REACTION OF METHYL RADICALS WITH FORMALDEHYDE
Authors: Toby S. , Kutschke K. O.
Published: May 2006

Azomethane was photolyzed in the presence of up to 30 mole per cent formaldehyde and formaldehyde-d2 at temperatures from 80 °C to 180 °C. The value of the activation energy for the abstraction reaction with methyl radicals was found to be 6.2 kcal mole−1 for CH2O and 7.9 kcal mole−1 for CD2O. The results indicated that the formyl radical was stable over the temperature range studied.
THEORY OF THE TRANSIENT PHASE IN AN ENZYME SYSTEM INVOLVING TWO ENZYME-SUBSTRATE COMPLEXES: THE CASE OF THE FORMATION OF PRODUCTS FROM THE FIRST COMPLEX
Authors: Ouellet Ludovic , Stewart James A.
Published: May 2006

A theoretical treatment is worked out for the kinetic scheme[Formula: see text]in which the concentration of P1 is followed. The steady-state and transient phase equations are obtained subject to the condition that the substrate concentration is greatly in excess of the enzyme concentration. The conditions under which evidence in favor of this mechanism can be obtained from experimental data are discussed. Under certain conditions, the weight of the enzyme corresponding to one active site can be determined. Methods for the evaluation of the different constants are described.
THE TRYPSIN CATALYZED HYDROLYSIS OFp-NITROPHENYL ACETATE
Authors: Stewart James A. , Ouellet Ludovic
Published: May 2006

The hydrolysis of p-nitrophenyl acetate (NPA) by trypsin has been investigated in the early stage of the reaction using stopped-flow techniques. The influence of pH on the initial rate suggests competitive inhibition of the active site of the enzyme by hydrogen ions. The dissociation constant of the enzyme obtained from the kinetics of this reaction (pK = 6.9) indicates possible catalysis by an ammo group or an imidazole group of the enzyme. Lysine methyl ester as an analogue of the enzyme catalyzes the hydrolysis of NPA under similar experimental conditions. The results are described in terms of an assumed mechanism and the nature of the catalytic site is discussed.
STERIC INHIBITION OF RESONANCE: II. BOND LENGTHS IN MESO-SUBSTITUTED ANTHRACENES
Authors: Trotter James
Published: May 2006

not available
CARBONYL AND THIOCARBONYL COMPOUNDS: I a. REACTION OF 9-DIAZOXANTHENE WITH o-QUINONES b. THE DIRECT PREPARATION OF HALOGENATED CYCLIC ETHERS FROM CERTAIN THIONES AND THEIR MOLLUSCICIDAL ACTIVITY
Authors: Latif Nazih , Fathy Ibrahim
Published: May 2006

The preparation and properties of 9-diazoxanthene are described. It reacts with tetrachloro-and tetrabromo-o-benzoquinone, 4-triphenylmethyl-1,2-benzoquinone, and phenanthraquinone to give the cyclic ethers IIIa, IIIb, IV, and V respectively. The action of hydrochloric acid – dioxane solution on the products is stressed.Tetrachloro- and tetrabromo-o-benzoquinone react with xanthione forming the halogenated cyclic ethers IIIa and IIIb respectively. A 1,2-benzopyran derivative IX is obtained by the action of tetrachloro-o-quinone on coumarin-2-thione. IX is toxic to Biomphalariaboissi snails in high dilution.
THE SYNTHESIS OF 2-KETOCYCLOHEXYLSUCCINIC ACID AND RELATED SUBSTANCES: IV. STUDIES ON SOME CIS- AND TRANS-FUSED γ-LACTONES
Authors: Charlesworth E. H. , Campbell H. J. , Stachiw D. L.
Published: May 2006

The cis and trans lactones of cyclohexanol-2-acetic acid and cyclohexanol-2-α-propionic acid have been subjected to alkaline hydrolysis to determine the relative ease of ring opening. In addition, a new synthesis by way of a Reformatsky reaction followed by dehydration and cyclization has been shown to yield the cis lactone. Finally, the first overtone band of the fundamental carbonyl stretching frequency has been identified.
THE LIMITING CONDUCTANCE OF AQUEOUS SOLUTIONS OF POTASSIUM IODATE, POTASSIUM CHLORATE, AND SILVER NITRATE AT 35.00 °C
Authors: Bock E. , Campbell A. N.
Published: May 2006

Measurements have been made of the equivalent conductances of aqueous solutions of potassium iodate, potassium chlorate, and silver nitrate at 35.00 °C at concentrations ranging from 0.8 × 10−4 to 16×10−4 N. From these, the limiting equivalent conductances and association constants A as obtained by the use of the Fuoss–Shedlovsky extrapolation procedure were found to be at 35.0 °C:[Formula: see text]
PHOTOCHEMICAL SEPARATION OF MERCURY ISOTOPES: III. THE REACTION OF Hg2026(3P1) ATOMS, PHOTOEXCITED IN NATURAL MERCURY VAPOR, WITH HYDROGEN CHLORIDE
Authors: McDonald C. C. , McDowell J. R. , Gunning H. E.
Published: May 2006

An investigation has been made of the reaction of Hg2026(3P1) atoms, photoexcited in natural mercury vapor, with flowing hydrogen chloride at 28–30 °C. Emphasis has been placed on the effect of reaction parameters on the Hg202 content of the calomel product of the reaction.Under fast-flow conditions it has been found that the calomel product contains 44% Hg202, corresponding to an enrichment of 48% over the normal abundance of 29.8%.In the presence of unsaturated compounds such as butadiene and benzene the enrichment is markedly increased. With butadiene and benzene as addends, the maximum enrichments were 98% and 85% respectively.The reaction with pure hydrogen chloride can be explained in terms of the sequence:[Formula: see text]where HgN is natural mercury and M is a third body, including the wall.In the presence of unsaturated compounds (U), additional reactions are postulated to occur:[Formula: see text]The increased enrichment in the presence of unsaturated addends is explained by the reduced rate of formation of HgNCl through cleanup of chlorine and hydrogen atoms by reactions [6] and [7].Under static conditions, the pure hydrogen chloride reaction formed a calomel product of normal Hg202 abundance. This finding is explained as a localized depletion of the unexcited mercury in Hg202, through reaction [1]. With increasing linear flow rate the depletion effect gradually disappears and enrichments maximize at high flow rates.The Hg202 enrichment was found to be very sensitive to the wall temperature of the Hg202 source. In a 50:50 v/v mixture of hydrogen chloride and butadiene the enrichment was found to decrease from 68% to 24% as the lamp temperature was raised from 25.5 °C to 50 °C. The effect is explained by temperature broadening of the emission line leading to overlap of the emission line on absorption contours adjacent to that of Hg202.Both the rate of deposition of the calomel product and the Hg202 enrichment were found to depend upon the concentration of natural mercury in the gas stream for hydrogen chloride – butadiene mixtures. Optimum conditions corresponded to a slight supersaturation of the stream with mercury vapor.
REARRANGEMENT STUDIES WITH C14: VII. THE ACETOLYSIS OF METHYL-C14-ISOPROPYLCARBINYL p-TOLUENESULPHONATE
Authors: Finlayson A. J. , Lee C. C.
Published: May 2006

Acetolysis of methyl-C14-isopropylcarbinyl p-toluenesulphonate (I) at reflux temperature gave a mixture of 2-methyl-2-butene (II), 2-methyl-1-butene (III), and 3-methyl-1-butene (IV) with no isolatable quantity of substitution product. The relative amounts of olefins II, III, and IV were measured by gas–liquid chromatography to be 80%, 18%, and 2%, respectively, and these were substantially verified by estimations with the isotope dilution technique. When the acetolysis was carried out at 50 °C, besides olefins II, III, and IV, present in relative amounts of 83%, 16%, and 1%, respectively, as determined by gas–liquid chromatography, a small quantity of substitution product, t-amyl acetate (V), was obtained. Under the conditions of acetolysis at reflux temperature, however, V was found to decompose to olefins II and III. Degradation of the olefinic products of acetolysis gave, among other compounds, radioactive acetone. Since acetone was derived from the chief product, II, its activity could be attributed to an isotope position rearrangement resulting from a 1,2-methide shift as one of the processes that gave rise to olefin II. This rearrangement amounted to about 2.5% and 0.9%, respectively, in olefin II from acetolysis at reflux temperature and at 50 °C. Considering all these results, it may be concluded that both substitution and elimination reactions could take place during acetolysis of I. The substitution reaction proceeded with neighboring hydrogen participation to yield t-amyl acetate, which would decompose to olefins II and III at reflux temperature under the acetolysis conditions. In the E1 reaction during acetolysis of I, processes involving no neighboring group participation to give olefins II and IV, with neighboring hydrogen participation to give olefins II and III, and with neighboring methyl participation to give isotopically rearranged olefins II and IV, all occurred, the process with neighboring hydrogen participation being predominant.
PREPARATION OF SOME FLUORINE-CONTAINING TRISUBSTITUTED AROMATIC HYDROXYLAMINES
Authors: Gingras B. A. , Bayley C. H.
Published: May 2006

The preparation and properties of aryl dialkyl hydroxylamines in which the aryl group is a fluorobenzene derivative, and the two alkyl substituents are 2-cyano-2-propyl groups, are described.
ELECTRON SPIN RESONANCE ABSORPTION OF ULTRAMARINE: EFFECT OF CATIONS
Authors: Matsunaga Yoshio
Published: May 2006

not available
LOW TEMPERATURE IRRADIATION OF MIXTURES OF HBr AND C2H4
Authors: Armstrong D. A. , Spinks J. W. T.
Published: May 2006

not available
IRRADIATION OF AQUEOUS CHLORAL HYDRATE WITH Sr90–Y90 BETA RAYS
Authors: Platford R. F. , Spinks J. W. T.
Published: May 2006

Air-saturated aqueous chloral hydrate has been irradiated with beta rays and the acid yield as determined by titration has been studied as a function of dose rate, temperature, and initial concentration of the chloral hydrate.The average lifetime of the intermediates has been found, by means of the rotating sector technique, to be about 0.5 second. Propagation and termination rate constants for the reaction have been calculated and an effort has been made to explain the results observed in terms of a free radical chain reaction.
A COMPARISON OF SLATER'S THEORY OF UNIMOLECULAR REACTIONS WITH EXPERIMENTAL DATA
Authors: Thiele Everett , Wilson David J.
Published: May 2006

Slater's theory of unimolecular reactions is tested by comparing theoretical and experimental values of the pressure at which the rate constant has fallen off from the high-pressure limit by 5%. A simplified method is used for calculating lower bounds to the theoretical value of this pressure. Agreement with experimental data on cyclobutane, cyclobutene, and nitrogen pentoxide is rather poor; experimental values are lower than the calculated lower bounds.
THE BIOGENESIS OF ALKALOIDS: XXI. THE BIOGENESIS OF (−)-HOMOSTACHYDRINE AND THE OCCURRENCE OF TRIGONELLINE IN ALFALFA
Authors: Robertson A. V. , Marion Léo
Published: May 2006

In an attempt to find the precursor of the piperidine ring in homostachydrine, young alfalfa shoots were fed (a) lysine-2-14C, (b) lysine-2-14C with pyridoxine, (c) lysine-2-14C with pyridoxine and folic acid, and finally (d) lysine-2-14C with pyridoxine, folic acid, and miethionine. In all cases the homostachydrine isolated from the harvested plants showed no radioactivity. It is shown that homostachydrine is not synthesized at the stage of growth at which the experiments were carried out. Alfalfa has been found to contain a hitherto unreported alkaloid shown to be trigonelline by comparison with an authentic sample. Both homostachydrine and trigonelline are found in the seeds, and are not actively synthesized in the plant until seed formation. Asparagine has also been isolated in relatively high yield.
THE BIOGENESIS OF ALKALOIDS: XXII. SOME INTERMEDIATE STEPS IN THE TRANSFORMATION OF TRYPTOPHAN TO GRAMINE
Authors: Breccia Alberto , Marion Léo
Published: May 2006

In germinating barley it is known that tryptophan is converted into gramine. In an attempt to find the intermediate steps in this conversion, it has been established that neither 3-indolylacetic acid, 3-indolylglyoxylic acid, 3-indolylaldehyde, nor 3-indolylacetamide (all labelled with 14C in the side chain) was a precursor of gramine. It has been shown, however, that both 3-indolylpyruvic acid and 3-indolylacrylic acid gave rise to radioactive gramine when fed to germinating barley. It is likely that these two acids constitute two intermediates in the pathway tryptophan–gramine.
INDEPENDENCE IN HYDROLYSIS OF CONDENSED PHOSPHATES
Authors: Smith M. Joyce
Published: May 2006

not available
NOTE ON THE PHOTOOXIDATION OF TETRAMETHYLRUBRENE
Authors: Hochstrasser Robin M.
Published: May 2006

not available
STUDY OF THE RADIOLYSIS OF BROMAL HYDRATE SOLUTIONS USING C14-LABELLED BROMAL
Authors: Heusinger H. , Woods R. J. , Spinks J. W. T.
Published: May 2006

Bromal labelled with C14 in the carbonyl group has been used to show that small amounts of carbon dioxide and carboxylic acids are produced in the radiolysis of aqueous bromal solutions. G values for the production of CO2 and carboxylic acid are about 7.5% and 15% of those for HBr production, respectively. The observed yield of carboxylic acid is in agreement with that found by titration.
DISPROPORTIONATION AND RECOMBINATION OF CYANISOPROPYL RADICALS: REARRANGEMENT OF DIMETHYLKETENECYANISOPROPYLIMINE TO TETRAMETHYLSUCCINODINITRILE
Authors: Talât-Erben M. , Isfendiyaroğlu A. N.
Published: May 2006

Evidence is presented that the ketenimine intermediate formed in the thermal decomposition of azo-bis-isobutyronitrile (AIBN) rearranges quantitatively to tetramethylsuccinodinitrile (TMSDN), mainly by a molecular mechanism. Interpretation of experimental data on the basis of a reaction scheme consistent with the nature of the main products and the features of the kinetics of the decomposition permits estimation, by means of a simple diagram, of the extent of disproportionation, as well as that of the normal and abnormal recombination of cyanisopropyl radicals. The result obtained for the latter is in good agreement with that determined previously by an alternative method. The analysis does not exclude absolutely the possibility of side reactions in which the azo-compound partly decomposes by a molecular process, and the intermediate decomposes into free radicals. However, it is concluded that these side reactions, if any, must be of minor importance.
REACTIONS OF TITANIUM HALIDES WITH ORGANOMETALLIC COMPOUNDS: I. STOICHIOMETRY OF THE REACTIONS BETWEEN TITANIUM TETRACHLORIDE AND SOME ORGANOMETALLIC COMPOUNDS
Authors: Malatesta Alberto
Published: May 2006

The over-all stoichiometry of the reactions involving titanium tetrachloride and various organometallic compounds has been determined. While titanium tetrachloride reacts with aluminum ethyldichloride and lead tetraethyl according to a 1:1 stoichiometry for any ratio investigated, the reaction between aluminum triethyl and titanium tetrachloride proceeds according to different paths when the ratio of the reagents is changed. Equations describing the reactions between aluminum triethyl and titanium tetrachloride, where the stoichiometries are respectively 1:1, 1:2, 1:3, are derived. Although a certain amount of hydrogen has been isolated after hydrolysis of the products of these reactions, no definite evidence is found for the presence of Ti(II).In all the experiments (except those in which an Al/Ti ratio greater than unity was used) substantial amounts of ethyl chloride and ethylene have been found, together with the main gaseous components, ethane and butane. A higher alkane was also isolated from the solid products of the reaction and is equal to the quantity of ethane liberated.
THE BIOGENESIS OF ALKALOIDS: XXIII. THE ROLE OF PROLINE AND ORNITHINE IN THE BIOGENESIS OF STACHYDRINE
Authors: Robertson A. V. , Marion Léo
Published: May 2006

When methionine-Me-14C, pyridoxine, and folic acid were fed to growing alfalfa, the stachydrine isolated from the plant was radioactive. This observation supports the assumption that stachydrine arises from proline by methylation since pyridoxine has been shown to induce the formation of proline from ornithine in the plant. However, the administration of labelled ornithine, pyridoxine, folic acid, and methionine to alfalfa failed to produce the radioactive alkaloid. Similar experiments were performed in which methionine-Me-14C and folic acid, methionine-Me-14C and pyridoxine, and finally methionine-Me-14C alone were fed to alfalfa, and in each case the stachydrine isolated from the plant was radioactive, while the homostachydrine remained inactive. Feeding proline-carboxyl-14C to alfalfa failed to produce radioactive stachydrine. It must be concluded that in alfalfa which is 2 to 3 weeks old, stachydrine is actively synthesized although homostachydrine is not. The implications of these observations are discussed.
NOTE ON THE INTRINSIC VISCOSITY OF POLYSTYRENE IN MIXED SOLVENTS
Authors: Henderson J. F. , Winkler C. A.
Published: May 2006

not available
ADSORPTION OF STERICALLY HINDERED PHENOLS ON CARBON
Authors: Wheeler Owen H. , Levy Eric M.
Published: May 2006

The Freundlich isotherms for the adsorption of some ortho-alkylated phenols on carbon from cyclohexane solution have been determined. The minimum surface area covered by the adsorbed phenols is compared with the area of the molecules themselves. Large alkyl groups ortho to the hydroxyl group greatly reduce the adsorption.
KINETIC EQUATIONS FOR ENZYME REACTIONS IN THE PRESENCE OF POWERFUL INHIBITORS
Authors: Krupka Richard M. , Laidler Keith J.
Published: May 2006

Steady-state equations are worked out for the case of a competitive inhibitor that is present in concentrations comparable with that of the enzyme; allowance is made for the inhibitor attached to the enzyme. Two cases are considered: in case 1 the enzyme and inhibitor form a simple addition complex, while in case 2 a molecule is split off. Methods of graphical analysis of rate data are described.
CONDUCTANCE IN THE RANGE OF MEDIUM CONCENTRATION
Authors: Campbell A. N. , Friesen R. J.
Published: May 2006

Equivalent conductances, densities, and viscosities of aqueous solutions of ammonium nitrate, of silver nitrate, and of lithium nitrate were determined at 25 °C and at 35 °C at concentrations ranging from 0.01 N to 1.0 N.Experimental equivalent conductances have been compared with those calculated by the Wishaw–Stokes and Falkenhagen–Leist equations. Suitable choice of one parameter, the distance of closest approach, permits reproduction of the experimental data with an error of less than 0.5%. A study of the deviations of the calculated from the experimental conductances reveals that the distance of closest approach (so-called) varies appreciably with concentration and temperature.
LIGHT ABSORPTION STUDIES: PART XIV. THE ULTRAVIOLET ABSORPTION SPECTRA OF PHENOLS
Authors: Dearden J. C. , Forbes W. F.
Published: May 2006

A spectral analysis of benzene derivatives is extended to substituted phenols. The discussion emphasizes hydrogen bonding and steric effects which occur in phenols. Some of the phenolic absorption bands are ascribed to locally excited states.
THE LUMINESCENCE OF COMPLEX MOLECULES IN RELATION TO THE INTERNAL CONVERSION OF EXCITATION ENERGY. PART I
Authors: Hochstrasser Robin M.
Published: May 2006

The relative fluorescence yields of a variety of double molecules have been measured as a function of the wavelength of exciting light. In some cases the yield from the second excited state is lower than from the first. This effect is attributed to either photodecomposition or to the enhancement of intramolecular energy transfer processes which can compete with the internal conversion between the excited singlet states. The experiments on bianthrone have suggested a method of elucidating the mechanism of the photochromic isomerization of this compound.
THE THERMODYNAMIC PROPERTIES OF THE SYSTEM CELLULOSE – WATER VAPOR
Authors: Morrison John L. , Dzieciuch Matthew A.
Published: May 2006

The heats of wetting by water of cotton cellulose containing various amounts of adsorbed and desorbed water were measured. These measurements together with those of the water vapor sorption isotherm were used to calculate the integral and differential enthalpies, free energies, and entropies of adsorption. Irreversible effects were avoided by vacuum-drying all samples at room temperature. The differential enthalpy values suggest hydrogen bonding. The differential entropies are explained in terms of changes in both the adsorbate and adsorbent.The surface area of the cellulose is calculated by applying the Brunauer–Emmett–Teller and Harkins–Jura equations to the adsorption isotherm. The changes in the differential enthalpies and entropies of adsorption follow the same sequence as the changes in film formation given by the surface area calculations.No hysteresis was observed in the heats of wetting of adsorbed and desorbed samples. It is concluded that the hysteresis of the sorption isotherm is an entropy phenomenon. This supports Barkas' explanation of hysteresis in terms of plastic deformation of a gel.
MOLTEN SALTS: THE DENSITY AND ELECTRICAL CONDUCTIVITY OF THE SYSTEMS: AgNO3–Ba(NO3)2, –Ca(NO3)2, AND –Mg(NO3)2
Authors: Murphy J. W. , Wetmore F. E. W.
Published: May 2006

The density and electrical conductivity of the systems AgNO3–Ba(NO3)2, –Ca(NO3)2, and –Mg(NO3)2 have been determined from 210 to 320° and from 0 to 20 equiv. %. The addition of magnesium nitrate causes the greatest shrinkage of the equivalent volume and reduction of the conductivity, barium nitrate the least.The low conductivity of the binary melts is explained in terms of a mechanism involving restricted jumps and variation of the energy barrier with temperature and kind of ion added.
THE SYSTEM Li+–Na+–K+–SO4− − AND WATER, AT 25.0 °C
Authors: Campbell A. N. , Kartzmark E. M.
Published: May 2006

The above system is a further stage in the study of the five-component system, containing the radicals Li2, Na2, K2, Cl2, SO4, and water. The double salts occurring are Li2SO4•K2SO4 and 3K2SO4•Na2SO4: no ternary salt is formed.
THE REACTION OF METHYL RADICALS WITH FORMALDEHYDE
Authors: Blake A. R. , Kutschke K. O.
Published: May 2006

The pyrolysis of di-t-butyl peroxide has been reinvestigated and used as a source of methyl radicals to study the abstraction reaction between methyl radicals and formaldehyde. At low [HCHO]/[peroxide] ratios the system was simple enough for kinetic analysis, and a value of 6.6 kcal/mole was obtained for the activation energy. At higher [HCHO]/[peroxide] ratios the system became very complicated, possibly due to the increased importance of addition reactions.
FREE RADICALS BY MASS SPECTROMETRY: XVI. Hg-PHOTOSENSITIZED DECOMPOSITIONS OF BIACETYL, ACETYLACETONE, AND ACETONYLACETONE
Authors: Harrison A. G. , Lossing F. P.
Published: May 2006

The Hg(3P1)-photosensitized decomposition of biacetyl proceeds by a central bond fission. Of the resulting acetyl radicals, at least 27% survive the primary act long enough to react with other radicals, or with a second excited Hg atom. Under conditions of high illumination, there is evidence that Hg(3S1) atoms produced by stepwise excitation also play a part in the reaction by forming excited biacetyl molecules with a lifetime of the order of 1 millisecond. The photosensitized decompositions of acetylacetone and acetonylacetone were examined qualitatively. The former dissociates mainly into an acetyl and an acetonyl radical, and the latter mainly if not exclusively to form CH3CO and C2H4COCH3 radicals. Further reactions of these radicals, and a possible structure for the C2H4COCH3 radical, are also discussed.
STERIC INHIBITION OF RESONANCE: V. NITROMESITYLENE
Authors: Trotter James
Published: May 2006

A detailed X-ray investigation of the crystal structure of nitromesitylene has shown that the nitro group is twisted 66° out of the plane of the aromatic ring about the C—N bond. The resulting decrease in resonance interaction compared with a completely planar model has been correlated with the characteristic NO2 vibration frequencies.
SOLVOLYSIS IN HYDROGEN AND DEUTERIUM OXIDE: III. ALKYL HALIDES
Authors: Laughton P. M. , Robertson R. E.
Published: May 2006

Rate data for the hydrolysis of a series of α- and β-methylated allyl, benzyl, and cycloalkyl halides in light and heavy water are compared. The major factor determining the rate ratio [Formula: see text] appears to be the relative stability of the initial solvation shell. When the relative viscosity of H2O and D2O is used as a measure of the relative stability of structure in bulk solvent, the observed kinetic isotope effect and the temperature dependence of the isotope effect can be rationalized in terms of accepted properties of aqueous solutions.Attention is drawn to the anomalous rate ratio kRBr/kRI > 1 which appears to be characteristic of solvolysis of these alkyl halides in pure water in contrast to other media.
EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART I. THE SMALL EBULLIOMETER
Authors: Blackmore W. R.
Published: May 2006

An ebulliometer that has been in routine use for the determination of the number average molecular weight of polymers is described. The results obtained with two different series of polythenes (which were also measured elsewhere) are given. These results show this ebulliometer to be subject to experimental difficulties which limit it to number average molecular weights of perhaps 20,000 depending on the precision required.
ELECTROMIGRATION OF IONS ABSORBED BY FILTER PAPER
Authors: Bailey R. A. , Yaffe L.
Published: May 2006

The variation with absorbance of the zone mobilities and obstructive factors for a number of inorganic ions has been investigated in acetic acid and in ammonium hydroxide at several concentrations. The results agree with the form of the semiempirical equation of Crawford and Edward. For a given ion the apparent obstructive factor defined as[Formula: see text]remains fairly constant as the concentration of the background electrolyte is changed, except in the very dilute region. However, the apparent obstructive factor varies with the ion and the background electrolyte indicating that specific effects, which are not considered in the equation, are important.
SODIUM DITHIONITE, DECOMPOSITION IN AQUEOUS SOLUTION AND IN THE SOLID STATE
Authors: Lister M. W. , Garvie R. C.
Published: May 2006

The decomposition of sodium dithionite has been investigated in alkaline aqueous solution. Under these conditions it decomposes by a first order reaction with a rate constant of 4.5 × 10−4 min−1 at 88.5 °C and an activation energy of 26.5 kcal/g-molecule. The ionic strength, and the concentration of the sodium hydroxide also present, affect the rate to some extent. A possible mechanism is suggested. The decomposition of solid sodium dithionite was also examined, and was found to give the best fit to the equations deduced assuming random nucleation, followed by linear growth of nuclei, with possible ingestion and interference of reacting zones. The activation energy of nucleus growth is 32 to 33 kcal/g-molecule, and that for nucleation probably between 40 and 45 kcal/g-molecule.