bluuebunny/crossref_metadata_2025 huggingface dataset:
INFRARED ABSORPTION OF THE SO2 CLATHRATE-HYDRATE MOTION OF THE SO2 MOLECULE
Authors: Harvey K. B. , Mccourt F. R. , Shurvell H. F.
Published: May 2006

not available
NMR SPECTRA OF O,O-DIALKYLORGANOPHOSPHORUS ESTERS. P31CHEMICAL SHIFTS BY HETERONUCLEAR SPIN DECOUPLING
Authors: Stothers J. B. , Robinson J. R.
Published: May 2006

not available
PROTON MAGNETIC RESONANCE AND THE STRUCTURE OF MALEIC HYDRAZIDE
Authors: Ohashi Osamu , Mashima Mitsuo , Kubo Masaji
Published: May 2006

not available
THE DECOMPOSITION OF SILYL PEROXIDES
Authors: Hiatt Richard R.
Published: May 2006

The thermal decomposition of tert-butyl trimethylsilyl peroxide has been investigated and found to be sensitive to acid and base catalysis and to the nature of the solvent. In heptane and iso-octane the first-order rate constant could be expressed as 1.09 × 1015e−41200/RT and in 1-octene as 3.90 × 1015e−41200/RT (sec−1). The half life at 203 °C was about 1 hour. The reaction was faster in aromatic solvents; in chlorobenzene it was complicated by formation of HCl from the solvent.Products of the reaction were acetone, tert-butyl alcohol and hexamethyldisiloxane.
DEUTERIUM–HYDROGEN EXCHANGE BETWEEN WATER AND SILK FIBROIN
Authors: Morrison John L.
Published: May 2006

A gravimetric method for measuring deuterium–hydrogen exchange between light and heavy waters and macromolecular solids has been applied to the fibrous protein, silk fibroin (Bombyxmori). The accessibility of the protein to water vapor can be estimated from the amount of exchange, and it appears to be related to the amorphous regions of the fiber. A comparison of the amount of exchange with the water monolayer content as obtained from the adsorption isotherm and the equilibrium evaporation technique suggests that the water molecules use the polar side chains of the amino acid residues as the sites of primary adsorption.
THE INHIBITED AUTOXIDATION OF STYREN: PART IV. SOLVENT EFFECTS
Authors: Howard J. A. , Ingold K. U.
Published: May 2006

The influence of solvents on the rate of the uninhibited oxidation of styrene can be roughly correlated with the dielectric constants of the solvents. It is suggested that the propagation reaction involves a dipolar transition state and that the magnitude of the solvent effects might be used to identify dipolar transition states in other oxidation reactions. The effect of solvents on the rate of oxidation of styrene inhibited by phenolic antioxidants is attributed to hydrogen bonding interactions between the phenolic hydroxyl group and the solvent. The magnitude of these interactions depends on the acidity of the phenol and on the degree of steric protection afforded the hydroxyl group by ortho-alkyl substituents.
COMPLEXES OF PLATINUM (0): I. COMPLEXES WITH TRIPHENYLPHOSPHINE AND SUBSTITUTED PHENYLACETYLENES
Authors: Allen A. D. , Cook C. D.
Published: May 2006

Kinetic and equilibrium measurements have been made on the exchange of one arylacetylene for another of different structure in the compounds bis-triphenylphosphineacetylene-platinum (0). The rate of exchange is proportional to the concentration of the complex but is independent of the reagent. The complexes are stabilized by electron-withdrawing groups in the acetylene ligand. A mechanism for the reactions is proposed in which an intermediate Pt(Ph3)2 is formed which has a significant stability.
UREA INCLUSION COMPOUNDS OF n-ALKYL BROMIDES AND IODIDES
Authors: Radell Jack , Brodman B. W. , Bergmann E. D.
Published: May 2006

The formation and stability of urea inclusion compounds of n-alkyl bromides and iodides were established from X-ray powder diffraction data. The stability of both homologous families is greater than would be expected from a consideration of the cross-sectional diameter of the molecules only. The procedure for isolating the complexes has been simplified.
THE SYNTHESIS AND PROPERTIES OF THE ANHYDROUS HEXACHLOROZIRCONATES OF SODIUM AND POTASSIUM
Authors: Lister R. L. , Flengas S. N.
Published: May 2006

The hexachlorozirconates of sodium and potassium have been produced in a closed system following the reaction:[Formula: see text]where M is Na and K, respectively. The zirconium tetrachloride was reacted at approximately 1 atm. pressure, and at temperatures of the alkali metal chloride between 425 °C and 525 °C. The densities, melting points, and the corresponding X-ray diffraction patterns for both compounds have been determined.
REARRANGEMENT STUDIES WITH 14C: XIX. THE REACTION OF 2-PHENYL-1-14C-ETHANOL WITH THIONYL CHLORIDE
Authors: Lee C. C. , Kroeger D. J. , Thornhill D. P.
Published: May 2006

The reaction of 2-phenyl-1-14C-ethanol with thionyl chloride in pyridine, dioxane, toluene, or excess thionyl chloride as solvent gave 2-phenylethyl chloride showing, respectively, about 0, 15, 44, and 48% rearrangement of the 14C-label from the C-1 to the C-2 positions. When reactions of 2-phenyl-1-14C-ethauol or 2-p-anisyl-1-14C-ethanol with thionyl chloride in dioxane or excess thionyl chloride were carried only to partial completion and the undecomposed chlorosulphites hydrolyzed by aqueous sodium hydroxide, the recovered alcohols showed only 0.1 to 0.5% isotope position rearrangement. This indicated a lack of return from ion-pairs to isotopically rearranged 2-arylethylchlorosulphite and suggested that the first stage of ionization may involve ion-pairs with structures that will not result in rearrangement on return to covalent bonding, or that the first ion-pair may decompose faster than it can return to reactant. The possibility that rearrangements via rigidly oriented ion-pairs and via the concerted SNi′ mechanism may represent the two extremes of a graded series is discussed. It is suggested that the relative contributions from the ion-pair and from the SNi′ mechanisms will depend on the stability of the carbonium ion as well as on the nature of the reaction solvent.
STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART I. THE DENSITIES AND MOLAR VOLUMES OF LITHIUM CHLORATE AND OF LITHIUM CHLORATE – LITHIUM NITRATE MIXTURES
Authors: Campbell A. N. , Nagarajan M. K.
Published: May 2006

The densities at different temperatures of pure molten lithium chlorate and of mixtures of lithium chlorate with lithium nitrate have been determined by a method of high precision. The change of molar volume with temperature has been interpreted in the light of possible structural changes in the melt.
RELATIVE RATES OF ABSTRACTION OF HYDROGEN FROM PROPANE AND n-BUTANE BY ATOMIC HYDROGEN
Authors: Kazmi H. A. , Roy D. J. Le
Published: May 2006

The activation energy for the abstraction of hydrogen from n-butane by atomic hydrogen was found to be approximately 1 kcal mole−1 smaller than for the analogous reaction with propane. The A factor is smaller by a factor of two. The A factors are discussed in terms of activated complex theory.
SYNTHESES OF ALPHA AMIDE AND PEPTIDE DERIVATIVES OF DL-ASPARTIC ACID
Authors: Zilkha A. , Lerman N.
Published: May 2006

not available
REACTION OF PERFLUOROALKYL RADICALS WITH MOLECULAR HYDROGEN
Authors: Kutschke K. O.
Published: May 2006

not available
AN IMPROVED METHOD FOR DECARBOXYLATING INDOLE-2-CARBOXYLIC ACIDS AND ITS APPLICATION IN THE SYNTHESIS OF 7-AMINO-DL-TRYPTOPHAN
Authors: Casini Giovanni , Goodman Leon
Published: May 2006

not available
ACID-CATALYZED REACTIONS OF VINYL COMPOUNDS: PART III. 2,7,9,10-TETRAMETHYLANTHRACENE FROM VINYL ACETATE AND TOLUENE
Authors: Pepper J. M. , Howell Margaret , Robinson B. P.
Published: May 2006

not available
REACTIONS OF ORGANOTIN COMPOUNDS: III. ADDITIONS OF DIMETHYLTIN DIHYDRIDE TO SIMPLE OLEFINS
Authors: Clark H. C. , Kwon J. T.
Published: May 2006

The addition reactions of dimethyltin dihydride with ethylene, butadiene, and cis- and trans-butene are described. With ethylene and butadiene, the products (CH3)2SnH(R) and (CH3)2SnR2 are fully characterized, where R = C2H5, or —CH2CH=CHCH3, the latter being the first butenyltin compounds to be reported. The butenes were virtually unreactive towards the dihydride. From a consideration of these and previous results, the possible reaction mechanism is discussed, and the tentative conclusion is reached that the rate-determining factor involves the formation of radicals from the tin dihydride.
REACTION MECHANISM STUDIES: 2. REDUCTIVE ELIMINATION OF 1,2-DIHALIDES WITH LITHIUM ALUMINUM HYDRIDE
Authors: King J. F. , Pews R. G.
Published: May 2006

1,2-Dibromides and bromohydrin p-toluenesulphonates of favorable geometry are readily reduced by lithium aluminum hydride in good yield to the corresponding olefin. Small quantities of water are found to have a temporaryacceleratingeffect on the reduction. The normal course of the reaction is a trans elimination, but when steric factors inhibit this, then substitution or cis elimination reactions may occur. It is shown that the cis elimination in the case of cis-1,2-dibromocyclohexane cannot involve reduction to the monobromide followed by dehydrobromination to the olefin. The reaction of some other 1,2-dihalides and related compounds with lithium aluminum hydride, and the reaction of a 1,2-dibromide with a number of other complex hydrides are reported.A general scheme for the mechanism of the olefin-forming elimination reaction is proposed. The limits that this study places on the possible positions of the reductive elimination of 1,2-dibromides with lithium aluminum hydride within this general scheme are discussed.
ELECTRODE POTENTIALS OF THORIUM TETRACHLORIDE IN ALKALI CHLORIDE MELTS
Authors: Srinivasan R. , Flengas S. N.
Published: May 2006

The electrode potentials of the system Th, ThCl4 (KCl, NaCl) were measured at various concentrations of thorium chloride, and at temperatures between 670 °C and 850 °C, using a silver – silver chloride reference electrode. It was shown by a direct gravimetric method that the reaction,Th(metal) + ThCl4(melt) = 2ThCl2(in melt),postulated by previous investigators, did not take place.The activity coefficients, and the other partial molal properties of the solutions of ThCl4, in the equimolar mixture of potassium and sodium chlorides, were calculated as a function of temperature from the e.m.f. measurements.
LCAO MO CALCULATIONS ON A SERIES OF NITRILES AND SOME RELATED MOLECULES BY A METHOD OF SELF-CONSISTENT FORMAL CHARGES
Authors: Moffat J. B.
Published: May 2006

A method of self-consistent charges has been applied to an LCAO MO calculation of a series of nitriles and some related molecules. The π-electron bond orders and π-electron densities were calculated for all the molecules considered. The entire calculation was programmed for operation on the IBM 1620 with alterations of the input data for the different molecules. The calculated bond orders yield bond lengths for C—C and C=C bonds in good agreement with experimental data, except when two or more triple bonds are present in the molecule. By the assumption of additivity of the bond orders obtained for the two orthogonal pi-electron systems, bond orders are obtained which yield bond lengths in satisfactory agreement with the experimental results for all CC bonds. For the nitrile bonds the calculated bond orders were fitted to a linear equation with the experimental bond lengths.
β-KETO ESTERS FROM REACTION OF ETHYL DIAZOACETATE WITH KETONES
Authors: Tai W. T. , Warnhoff E. W.
Published: May 2006

The Lewis acid catalyzed reaction of diazoacetic ester with ketones has been extended. Convenient conditions have been found for the preparation of some pure β-keto esters in fair to good yields by reaction of ethyl diazoacetate with ketones in the presence of boron trifluoride at −40° to −70°. The reaction is apparently general since cyclopentanone, cyclohexanone, and acetophenone gave nearly pure β-keto esters in 44%, 79%, and 38% yields, respectively, based on diazoacetic ester. In the case of acetophenone the phenyl group migrated. Acetone gave 78% of a mixture of β-keto ester and glycidic ester.
THE BEHAVIOR OF LEAD ELECTRODES IN SULPHURIC ACID SOLUTIONS
Authors: Ekler K.
Published: May 2006

Lead electrodes were anodically etched in NH2SO3H. Immersion potentials, self-passivation potentials, passivation times, PbO2/O2 potential, and the potential of the first discharge plateau were determined in H2SO4 solutions ranging from 0.5 to 20.0 N and were found to be concentration-dependent. Interruption of the anodizing current had no detectable influence on passivation time. Data obtained with the anodizing current turned on fall into three categories; those obtained with (1) short-immersion anodes, (2) anodes which had reached a hydrogen-like potential, and (3) anodes which were self-passivated before the current was switched on. An inflection in the relation between potential and time during charging was investigated. Its length was dependent upon acid concentration and current density, while its potential was +300 ± 30 mv, and seemed to correspond to the self-passivation potential. The lengths of the first and second discharge plateaus increased with the number of coulombs passed and were dependent upon acid concentration, but were identical for electrodes treated by four different methods. The hydrogen-like potential appeared to be due to the presence of PbO•PbSO4. The self-passivation potential seemed to be caused by formation of PbO.
D-MANNOFURANOSE 2,3-CARBONATE. PREFERRED SIZE OF THE SUGAR RING IN SOME FUSED-RING DERIVATIVES
Authors: Perlin A. S.
Published: May 2006

Treatment of 6-O-trityl-D-mannose with phosgene gives 6-O-trityl-D-mannose 2,3-carbonate (II), which on partial hydrolysis, yields D-mannose 2,3-carbonate (VI). Chemical properties of II and VI agree with the proposition that fusion of the cyclic carbonate group at the 2- and 3-positions of D-mannose converts the latter to a furanose derivative. Nuclear magnetic resonance spectral evidence supports the furanoid assignment and indicates also that in aqueous solution VI does not rearrange significantly to a pyranose form. Substantial disagreement is found between proton-proton coupling observed for VI and corresponding data predicted from the Karplus curve. A similar situation is encountered with a related fused-ring derivative, 2,3-O-isopropylidene-L-rhamnose.5-O-Methyl-D-mannofuranose has been synthesized via methylation of II. 5,6-Di-O-acetyl-α-D-mannofuranosyl bromide 2,3-carbonate (VIII), prepared from VI, permits synthesis of either of the anomeric methyl D-mannofuranosides. On treatment of VIII with methanol in the presence of excess sodium the α-D-glycoside is obtained, whereas in the presence of silver oxide a β-D-anomeric derivative is formed.
GAS–SOLID EXCHANGE REACTIONS: ZINC VAPOR AND POLYCRYSTALLINE ZINC SULPHIDE
Authors: Secco E. A.
Published: May 2006

The exchange kinetics of zinc vapor with polycrystalline zinc sulphide, wurtzite structure, have been studied in a static system in the temperature range 720–960 °C.Plots of log10(1−α*), i.e. exchange fraction, versus time reveal two processes. The initial process is a rapid simple exchange, for which the data fit a first-order rate law and which persists to a depth of 15–18 molecular thicknesses. At this depth the second, slower process, which appears to be diffusion-controlled, sets in. Kinetic and structural interpretations of these results along with the existing data on Zn–ZnO exchange are discussed.
ALIPHATIC CHEMISTRY OF FLUORENE: PART IX. SOME BIFUNCTIONAL DERIVATIVES
Authors: Bavin P. M. G.
Published: May 2006

Methyl phenanthrene-9-carboxylate, dimethyl phenanthrene-9,10-dicarboxylate, and N,N-dimethyl phenanthrene-9-carboxaraide have been prepared directly from fluorene by a novel route. Neighboring group participation by carbomethoxy has been clearly demonstrated in the reactions of some 9,9-disubstituted fluorenes.
THE MERCURY-PHOTOSENSITIZED DECOMPOSITION OF AMMONIA AND AMMONIA–PROPANE MIXTURES
Authors: Takamuku S. , Back R. A.
Published: May 2006

A study of the mercury-photosensitized decomposition of ammonia, both with pure ammonia and with propane added as a scavenger for hydrogen atoms, suggests that the quantum yield of the primary decomposition into H and NH2 is much less than unity at 33 °C and rises with increasing temperature. The interaction of ammonia–propane mixtures with Hg 6(3P1) atoms cannot be explained in terms of simple competitive quenching; a tentative mechanism involving a long-lived Hg 6(3P1) – propane complex and Hg 6(3P0) atoms has been suggested. A temperature dependence in the relative quenching rates of C3H8 and C3D8 has also been observed.
NUCLEAR MAGNETIC RESONANCE STUDIES OF THE PROTONATION OF WEAK BASES IN FLUOROSULPHURIC ACID: IV. PHENOLS AND AROMATIC ETHERS
Authors: Birchall T. , Bourns A. N. , Gillespie R. J. , Smith P. J.
Published: May 2006

The n.m.r. spectra of phenol, anisole, and other phenols and aromatic ethers in solution in fluorosulphuric acid and in 70% perchloric acid show that in every case they protonate on an aromatic carbon. Earlier evidence from ultraviolet spectroscopy that phenol and anisole protonate on oxygen is reinterpreted.
CONDENSATION OF HEXACHLOROCYCLOPENTADIENE WITH DIETHANOLAMINE
Authors: Kamal Marwan R. , Wicklatz John E.
Published: May 2006

not available
REARRANGEMENT STUDIES WITH 14C. XX. SOME OBSERVATIONS ON REACTIONS BETWEEN GRIGNARD REAGENT, COBALTOUS BROMIDE, AND 2-PHENYLETHYL BROMIDE
Authors: Lee C. C. , Thornhill D. P.
Published: May 2006

not available
SYNTHESIS OF POTENTIAL ANTINEOPLASTIC AGENTS. XII. SOME BIS(2-CHLOROETHYL)AMINES CONTAINING A p-FLUOROPHENYL GROUP AND RELATED COMPOUNDS
Authors: Popp Frank D. , Alwani Dru W.
Published: May 2006

not available
CHEMISTRY OF ETHYL 2-METHYL-4-OXO-Δ2-PYRROLINE-3-CARBOXYLATE AND RELATED COMPOUNDS
Authors: Atkinson R. S. , Bullock E.
Published: May 2006

Ethyl 2-methyl-4-oxo-Δ2-pyrroline-3-carboxylate (Ia) is oxidized by one-electron oxidizing agents to a colored dimer which has been synthesized by an alternative route. Acetylation of (Ia) and its N-methyl derivative (Ib) gives a variety of products some of which show unusual infrared absorptions. The products of dimerization of (Ia) and (Ib) in strong acid show nuclear magnetic resonance absorptions at variance with previously claimed structures and alternatives are suggested.
ON THE ANODIC OVERVOLTAGE IN ALUMINUM ELECTROLYSIS
Authors: Thonstad Jomar , Hove Eirik
Published: May 2006

The overvoltage on the carbon anode in aluminum electrolysis has been measured against a CO2/C reference electrode placed in the cryolite melt. The behavior of the reference electrode was first investigated against the aluminum cathode. This galvanic cell showed a stable potential of 1.15 V, which was close to the reversible potential for the cell reaction in aluminum electrolysis. Similar measurements were made with CO/C and CO2,CO/C electrodes. The potential of the CO/C electrode was in fair agreement with the reversible potential for the most probable cell reaction. The potentials obtained with CO2–CO mixtures were intermediate between those for the pure gases, increasing with increasing CO2 content. An explanation for the behavior of the CO2,CO/C electrode is suggested.The anodic overvoltage depended only to a limited extent on the chemical reactivity of carbon with respect to oxygen. Graphite anodes showed higher overvoltage than all other types of carbon anodes. Catalyzing and inhibiting additives to the carbon had small but significant influences on the overvoltage. Straight Tafel plots were obtained with slopes varying between 0.26 and 0.27. On this basis it is shown that the overvoltage may be due either to slow transport of oxygen ions through the double layer or to slow reaction between chemisorbed oxygen and carbon.
PLATINUM(II) COMPLEXES: INFRARED SPECTRA IN THE 300–800 CM−1 REGION
Authors: Allen A. D. , Theophanides T.
Published: May 2006

Bands have been assigned to stretching frequencies of bonds between platinum and chlorine, nitrogen and oxygen which are observed in the far infrared region. The positions of these bands have been related to the structures of several complexes. Improved procedures are given for the preparation of complexes of the type K[PtCl3L] and trans- PtCl2L(am), where L is an unsaturated organic ligand and am is an aromatic amine.
COMPLEXES OF STANNIC CHLORIDE WITH AROMATIC HYDROCARBONS AND OXYGEN-CONTAINING DONORS IN SOLUTION
Authors: Myher J. J. , Russell K. E.
Published: May 2006

Complex formation between stannic chloride and various alkylbenzenes has been investigated by means of optical measurements. It is found that weak 1:1 complexes are formed in methylene chloride solution at 25 °C. The absorption at 355 mμ can be used to determine the concentration of free stannic chloride in benzene to which oxygen-containing donors have been added. The results are interpreted in terms of 1:1 and 1:2 complex formation between stannic chloride and donor. For the stronger donors such as tetrahydrofuran and acetone, the main complexes formed with excess of stannic chloride must contain equimolar amounts of stannic chloride and donor, and it is probable that they involve tin with a coordination number of five. Ethyl esters of chloroacids are very much weaker donors than ethyl esters of unsubstituted acids. The heat of reaction for the addition of a donor molecule to the 1:1 complex is usually close to the heat of reaction for the addition of the first donor molecule to stannic chloride. The decrease in entropy in each case is approximately 30 e.u./mole.
THE RADIATION CHEMISTRY OF SQUALENE
Authors: Danon Jeanne , Golub Morton A.
Published: May 2006

Squalene was irradiated with Co60 γ-rays at room temperature and with 1-MeV electrons at −30 °C. The main radiation-induced effects, and their G-values for the room temperature irradiations, were loss of unsaturation (4.6), crosslinking (1.35), trans → cis isomerization (0.83), and evolution of hydrogen (0.58). The G-values for the first three processes in the low temperature runs were 3.8, 0.82, and 0.83, respectively. The large drop in unsaturation is attributed in part to the formation of crosslinks involving double bonds, but principally to cyclization. The loss of double bonds occurs only in the immediate vicinity of the crosslinks and not at random throughout the irradiated squalene. This result has important implications for the radiolysis of diene polymers. Squalene in 10% benzene solution isomerizes with a much higher yield (apparent G-value of 2.6 trans double bonds converted initially per 100 eV absorbed by both solute and solvent) than that of the pure olefin, indicating very efficient energy transfer from excited benzene molecules to the squalene double bonds. The isomerization in the solution case was accompanied by a loss of double bonds in squalene (G-value of 0.98) due to phenylation as well as to the other indicated saturation reactions.
FOMECIN A AND B, PHENOLIC ALDEHYDES FROM THE BASIDIOMYGETE FOMES JUNIPERINUS
Authors: McMorris T. C. , Anchel Marjorie
Published: May 2006

Fomecin A and B obtained previously from the basidiomycete Fortiesjuniperinus Schrenk have been characterized as 6-hydroxymethyl-2,3,4-trihydroxy benzaldehyde and 2,3,4-trihydroxy o-phthalaldehyde, respectively.
STRONGLY BASIC SYSTEMS: III. THEH−FUNCTION FOR VARIOUS SOLVENT SYSTEMS
Authors: Stewart Ross , O'Donnell J. P.
Published: May 2006

The Hammett acidity function concept has been used to determine simultaneously the pKavalues of 24 substituted anilines and diphenylamines and the H−values of various solvent systems. The following solvent systems were examined (the most basic H−value obtained for each is shown in parentheses): water containing benzyltrimethylammonium hydroxide (16.20); pyridine–water containing tetramethylammonium hydroxide (18.91); sulpholane–water containing tetramethylammonium hydroxide (19.18); dimethyl sulphoxide–water containing tetramethylammonium hydroxide (18.61); water containing lithium hydroxide (14.31).In addition to these results adjustments have been made to previously published scales for hydrazine–water (15.08) and ethylenediamine–water (15.48).
THE ACTIVATION PROCESS IN SOLVOLYSIS
Authors: Robertson R. E.
Published: May 2006

The structural nature of water is a major factor in determining the solvent isotope effect and the apparent heat capacity of activation for solvolysis. The consequences of this assumption are examined for the SN2 mechanism in terms of solvation changes at the transition state and the probable make-up of the activation energy.
ULTRASONIC ABSORPTION IN CRITICAL BINARY LIQUID SYSTEMS. II
Authors: Kruus Peeter
Published: May 2006

The results of ultrasonic absorption measurements for the systems perfluoromethylcyclohexane – carbon tetrachloride and triethylamine–water are presented. A pulse reflection method was used for the measurements. Intermolecular correlation lengths were calculated from the absorption data for these and two other systems. They are in reasonable agreement with lengths calculated from light scattering data. The absorption results also substantiate the suggestion that, in the critical solution region, the system may already be in two phases. However, these are not present in the form of two distinctly separated phases, but as regions in a type of emulsion.
METHYLATION OF METALATED INDENE AND METHYLINDENE
Authors: Bosch A. , Brown R. K.
Published: May 2006

The reaction of metallic lithium and potassium with indene and fluorene in refluxing 1,2-dimethoxyethane (DME) yields reduction products of indene and fluorene, 1-metalated indene, and 9-metalated fluorene, and as well is accompanied by the production of some hydrogen gas due to the acidic methylene group. The amount of hydrogen is small for fluorene but quite substantial for indene.Metalation of indene, 1-methylindene, and 3-methylindene in refluxing DME, followed by methylation of these metalated indenes at 0°, gave a mixture consisting of starting material, the corresponding indan, monomethylindene, dimethylindene, and in some cases trimethylindene. Two competing reaction mechanisms resulting in the formation of the metalated indenes are suggested and possible routes for the formation of the di- and tri-methylindenes are examined.
CLEAVAGE OF XANTHENE ETHERS: A NEW ROUTE TO 9-SUBSTITUTED XANTHENES
Authors: Latif N. , Fathy I. , Mishriky N.
Published: May 2006

9,9-(Tetrachloro-o-phenylenedioxy) xanthene (IIa) and its thio-analogue (IIb) are cleaved by hydrazines to give the corresponding hydrazones of xanthone and thiaxanthone, respectively, together with tetrachlorocatechol. The unsaturated nitriles (Va), (Vb), and (Vc) are produced similarly by the action of malononitrile and cyanoacetic ester. Dixanthenyl ether itself reacts in a similar manner with active hydrogen compounds to give the corresponding 9-xanthyl derivatives. (IIb) is prepared by the action of 9-diazothiaxanthene on tetrachloro-o-benzoquinone and is readily cleaved by lithium aluminum hydride to give thiaxanthene and tetrachlorocatechol. The reaction mechanisms are discussed.
HYDROGENOLYSIS OF CARBOHYDRATES. X. HYDROGENOLYSIS OF (±)-EPI-INOSOSE-2
Authors: Gorin P. A. J.
Published: May 2006

not available
AN ELECTRON IMPACT STUDY OF METHYLMERCAPTOBENZYL CHLORIDES
Authors: Meyer F. , Harrison A. G.
Published: May 2006

not available
SYNTHESIS OF TRYPTOPHAN-CARBOXYL-14C
Authors: Slater G. P.
Published: May 2006

not available
REARRANGEMENT STUDIES WITH 14C: XXI. SIDE CHAIN REARRANGEMENT AND FRAGMENTATION FOLLOWING FRIEDEL–CRAFTS ALKYLATION OF BENZENE WITH β-14C-ETHYL IODIDE
Authors: Lee C. C. , Hamblin M. C. , Uthe J. F.
Published: May 2006

The aluminum chloride catalyzed reaction between β-14C-ethyl iodide and benzene in 1,2,4-trichlorobenzene as solvent was studied under different conditions of temperature and reaction time. Yields of ethylbenzene were estimated by isotopic dilution. Up to 20% rearranged product, α-14C-ethylbenzene, was found. The trend indicated that yield of ethylbenzene was lower and side chain rearrangement greater when the reaction mixture was heated at higher temperature for longer time. The rearrangement apparently occurred after the initial formation of β-14C-ethylbenzene. After a reaction time of 5 min at 154 °C, only 0.1–0.3% unreacted and unrearranged β-14C-ethyl iodide was recovered while the ethylbenzene obtained from the reaction showed about 2% rearrangement. When β-14C-ethylbenzene was heated with aluminum chloride in 1,2,4-trichlorobenzene for 2 or 24 h, rearrangement to α-14C-ethylbenzene was observed. In some experiments, a fragmentation product, toluene, was isolated. Its specific activity suggested that 1 mole of active ethylbenzene gave 2 moles of toluene only one of which was active. The mechanistic implications of these findings are discussed.
CHEMICAL REACTIONS IN ELECTRICAL DISCHARGES: I. THE SPECTRUM OF THE METHANE–OXYGEN SYSTEM AT LOW PRESSURE IN THE POSITIVE COLUMN OF A D-C. GLOW DISCHARGE
Authors: D'enghien Pierre A. Bois , Deckers Jacques M.
Published: May 2006

A technique is described which permits the study of changes in the spectra emitted by fast flowing reacting gas mixtures in the plasma of the positive column of a weak d-c. glow discharge. In certain cases a quantitative relationship is shown to exist between the concentration of a species and the intensity of emission of its spectrum. In particular such a correlation exists between the emission intensity of CO and its concentration. Use of this fact is then made to follow the rate of formation of carbon monoxide in methane–oxygen mixtures flowing through a discharge. The mechanism of formation of the various emitters either by means of a chemical reaction or by electron impact on molecules or radicals is discussed. It is concluded that to account for the rate of formation of CO, at least in the early stages of the presence of the gases in the discharge, before the steady state concentrations of atoms, radicals, and molecules have been approached, most of the energy of the electrons is used in breaking chemical bonds. The electric Held values needed to impart the necessary amount of energy to the electrons are of the same magnitude as those measured in this laboratory (~60 V cm−1).
DIAMAGNETIC SUSCEPTIBILITIES OF SOME COMPOUNDS CONTAINING OXYGEN LINKED TO NITROGEN OR PHOSPHORUS
Authors: Lister M. W. , Marson R.
Published: May 2006

The diamagnetic susceptibilities of a number of compounds containing oxygen linked to nitrogen or phosphorus have been measured. The results are interpreted in terms of the apparent contribution of the oxygen atoms to the susceptibility in these and other series of compounds, and are compared with other evidence on the nature of the bonds to oxygen. The results support the usual formula of an amine oxide as R3N → O, but phosphine oxides behave as would be expected for R3P = O. Phosphorus oxyhalides have molar susceptibilities about 4.6 (in units of −10−6 e.m.u.) larger than the corresponding trihalides, a difference close to that for singly bound oxygen in ethers or alcohols. Each oxygen contributes 4.4 in trialkyl phosphites, as might be expected for P(OR)3; but the value in dialkyl phosphites is 4.9 per oxygen, thereby showing behavior similar to that of carboxylic esters. The extra oxygen in trialkyl phosphates as compared with trialkyl phosphites contributes 9.4, a surprisingly large amount.
A MODEL FOR THE HYDROGEN BOND AND PROTON TRANSFER REACTIONS
Authors: Bader R. F. W.
Published: May 2006

A simple extension of Platt's model for determining the force constants in diatomic hydrides is used to investigate the properties of transition states for proton transfer reactions. The model is first tested by comparing the predicted and observed changes in bond lengths and stretching and bending frequencies for [Formula: see text] systems. The quantities predicted for the transition state are the geometry and the perpendicular bending frequencies. The implications of the results with regard to the interpretation of hydrogen–deuterium kinetic isotope effects are discussed. In particular, the variations in both the isotope effect and the geometry of the transition state with changing acid or base strength are considered in detail.
KINETICS AND MECHANISMS OF THE THERMAL DECOMPOSITION OF ACETALDEHYDE: I. THE UNINHIBITED REACTION
Authors: Eusuf M. , Laidler K. J.
Published: May 2006

The kinetics of the uninhibited decomposition of acetaldehyde have been reexamined. The initial rates of the decomposition of pure acetaldehyde show strict three-halves-order dependence at temperatures from 480 to 525 °C, and the activation energy is 47.6 kcal per mole. Foreign gases, which decrease the rate of reaction, cause a significant increase in order. The rate of ethane formation is second order in acetaldehyde, and Trenwith has found the hydrogen formation to be second order in acetaldehyde. The results are shown to be consistent only with a mechanism involving second-order initiation and the third-order reaction 2CH3 + M → C2H6 + M as the terminating step. The rate of the initiation process is increased only to a small extent by the addition of inert foreign gases; it is suggested that the initial process may be CH3CHO + CH3CHO → CH3CHOH + CH3CO, with a subsequent breakdown of CH3CHOH into CH3CHO + H. The mechanism is shown to account for the overall kinetic behavior and for the formation of the minor products.
RADIOLYSIS OF CYCLOHEXANONE: I. PURE LIQUID
Authors: Singh Ajit , Freeman Gordon R.
Published: May 2006

The G values of the major products of the gamma-radiolysis of liquid cyclohexanone are: hydrogen (0.76), carbon monoxide (0.45), 1-pentene (0.22), 5-hexenal (0.85), cyclohexenone (0.4), cyclohexanol (0.5), "dimer" (1.15), and polymer (1.8 cyclohexanone units). A large number of minor products were also measured.The amount of ring cleavage that occurs in cyclohexanone is much greater than that which occurs in the radiolysis of cyclohexane. The increase has been attributed to the influence of the carbonyl group on the course of the reaction. Ring cleavage occurs preferentially at the C—C bonds to the carbonyl group.Much of the radiolytic reaction appears to occur from energy states higher than those of importance in the photolytic studies.
sGAS–LIQUID CHROMATOGRAPHY OF TERPENES: PART XI. THE VOLATILE OIL OF THE LEAVES OF JUNIPERUS SCOPULORUM SARG
Authors: Rudloff E. von , Couchman F. M.
Published: May 2006

The neutral leaf oil of Rocky Mountain juniper was analyzed by gas–liquid chromatography. d-Sabinene was found to be the major constituent (45.7%) and smaller amounts of d-limonene (11.4%), d-α-pinene (4.2%), γ-terpinene (1.15%), p-cymene (1.4%), l-linalool (1.2%), d-terpinen-4-ol (2.9%), citronellol (0.2%),l-β-elemene (0.2–0.3%), three isomeric cadinenes (2.7%), l-elemol (6.0%), and safrole (1.85%) were isolated. α-Thujene, camphene, car-3-ene, myrcene, α-terpinene, terpinolene, thujone, isothujone, methyl citronellate, sabinyl acetate, sabinol, geraniol, α- and δ-cadinol, and trans-isoeugenol were tentatively identified. An unidentified acetate (II) (4.7%) was isolated from the oxygenated sesquiterpene fraction and another appears to be present in trace amounts.The composition of the oils from the leaves of four local ornamental plants was found to differ significantly from that of the wild juniper.
MECHANISM OF THE BIMOLECULAR NUCLEOPHILIC DISPLACEMENT REACTION ON α-HALOCARBONYL COMPOUNDS
Authors: Sisti A. Joseph , Lowell Seymour
Published: May 2006

Two mechanisms have previously been postulated for the high reactivity of a-halocarbonyl compounds in the nucleophilic displacement reaction. Kinetic data for α-halocarbonyl compounds and various nucleophiles (cyanate, acetate, azide, and thiocyanate) in anhydrous methanol are presented. The new data, in conjunction with previously reported results, are in better agreement with the concept of neighboring group overlap than with that of Pearson's electrostatic facilitation between the nucleophile and the α-carbonyl group.
A SPECTROPHOTOMETRIC REEXAMINATION OF THE SPECTRA AND STABILITIES OF THE IRON (III) – TIRON COMPLEXES
Authors: McBryde W. A. E.
Published: May 2006

Variations in the spectra of the aqueous solutions of the iron (III) – sodium catechol disulphonate (Tiron) complexes may be interpreted in relation to pH of the solutions to show which complexes are present at any chosen pH. With this knowledge it is possible in this system to evaluate equilibrium constants for the formation of each complex in turn. Combining these with separately determined acidity constants for Tiron, the stability constants of the complexes may be calculated. These have been determined for background solutions of potassium nitrate or sodium perchlorate each at three different concentrations, and for three different ratios of reagent to metal. Averages of a number of determinations made under these conditions are given in Table III of the paper. The constant K1 in perchlorate media shows an unmistakable dependence suggestive of the existence of a protonated species at low pH as well as the simple complex ML. However, there is some ambiguity in the interpretation of the results so that the exact nature of the protonated complex cannot be decided.
AZOXYCOMPOUNDS: I. THE PHOTOLYSIS OF AZOXYMETHANE
Authors: Gowenlock B. G.
Published: May 2006

A study of the photolysis of azoxymethane has been made. The reaction products include nitrogen, nitrous oxide, methane, and ethane. The ratio N2:N2O is independent of temperature and two primary photolytic processes are postulated to account for this fact. On the assumption that methane arises from the reaction CH3 + CH3N2OCH3 → CH4 + CH2N2OCH3, the activation energy of this reaction is 6 ± 2 kcal/mole. Other reactions that take place during the photolysis are discussed.
THE RATE OF REACTION OF ACTIVE NITROGEN WITH ETHANE, PROPANE, AND NEOPENTANE
Authors: Jones W. E. , Winkler C. A.
Published: May 2006

The reactions of active nitrogen with ethane, propane, and neopentane have been studied over the temperature range 0 to 450 °C. A cobalt probe technique was used to stop the reactions after various reaction times. Second order rate constants have been calculated on the assumption that nitrogen atoms are the only reactive species in active nitrogen. Broken Arrhenius lines were obtained for both the ethane and neopentane reactions but this behavior was not observed with the propane reaction. The dual activation energies have been attributed to a mechanism involving initiation by both excited molecules and either nitrogen or hydrogen atoms. Methods are outlined by which an estimate has been made of the concentration of excited species assumed to be involved in the ethane reaction.
THE IONIZATION BEHAVIOR OF AMIDES IN CONCENTRATED SULPHURIC ACIDS: I. A NEW ACIDITY FUNCTION BASED ON A SET OF PRIMARY AMIDE INDICATORS
Authors: Yates Keith , Stevens Joan B. , Katritzky A. R.
Published: May 2006

A set of eight suitably substituted primary amides of progressively weaker basicity have been prepared. Their ionization curves have been determined in sulphuric acids by spectrophotometric methods. These show good overlap and parallelism for successive indicators, enabling the pK values of the indicators to be determined by direct stepwise comparison. Using these pK values and measured ionization ratios, values of a new acidity function, HA, have been obtained for aqueous solutions up to 82% sulphuric acid. The HA function decreases much less rapidly than H0 in this range, being nearly 3 log units less negative at the highest acidity studied. The reasons for this large difference are discussed. The HA function is shown to be applicable to other amides which have not been employed as indicators.
STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART IV. THE ELECTRICAL CONDUCTANCES OF MOLTEN LITHIUM CHLORATE AND OF ITS MIXTURES WITH PROPYL ALCOHOL, LITHIUM NITRATE, WATER, METHYL ALCOHOL, AND LITHIUM HYDROXIDE
Authors: Campbell A. N. , Williams D. F.
Published: May 2006

The electrical conductance and its temperature dependence of molten lithium chlorate have been determined. Similar results have been obtained for lithium chlorate melts containing small quantities of methyl alcohol, propyl alcohol, lithium nitrate, lithium hydroxide, and water.The results obtained, taken in conjunction with the results of previous work, all indicate that the melt is complex. There is probably considerable association and this is especially evident slightly above the melting point: at temperatures in this region the temperature change of the properties of the lithium chlorate melt is greatest.The activation energy of conductance is approximately the same as the activation energy of viscous flow, for pure lithium chlorate melt and for mixtures of lithium chlorate with lithium nitrate. From this it appears that the melt constituents are not principally the simple ions, but that some form of cohesion exists between the simple constituents of the melt.The addition of water to the lithium chlorate melt causes the melt properties to alter considerably, especially the transport properties, viscosity and conductance. It is suggested that these changes may in part be due to a breakup of the structural entities of the pure melt, though the increase in electrical conductance cannot be completely explained in this way. A cryoscopic investigation seems to indicate that water is •not present as such in the melt.
AN ELECTRON IMPACT STUDY OF METHYL PHENYL ETHERS
Authors: Meyer F. , Harrison A. G.
Published: May 2006

The mass spectra of anisole, anisole-methoxy-d3, meta and para methylanisole, meta and para methyl-d3-anisole, and meta and para niethylanisole-methoxy-d3 have been recorded. From the deuterium labelling and appearance potential studies, the main fragmentation paths on electron impact have been elucidated. The energetics of formation of the CH3OC7H6+ ion from the methylanisoles, benzyl methyl ether, 7-methoxycycloheptatriene, and the ethylanisoles have been studied.
ASYMMETRIC SYNTHESIS BY THE REACTION OF MERCURIC ACETATE WITH OPTICALLY ACTIVE THIOACETALS
Authors: Painter Edgar Page
Published: May 2006

not available
THE REACTION OF UNSATURATED CARBOHYDRATES WITH CARBON MONOXIDE AND HYDROGEN: III. STRUCTURE AND STEREOCHEMISTRY OF THE HEXITOLS FROM 3,4-DI-O-ACETYL-D-ARABINAL
Authors: Rosenthal Alex , Koch Hans J.
Published: May 2006

not available
THE PHENYL EFFECT IN DISTORTION POLARIZATION
Authors: Huber Helmut , Wright George F
Published: May 2006

Diphenylmercury has been used as a model to show that the electron and atom parts of the distortion polarization cannot reliably be evaluated by optical methods. The measured electron polarization extrapolated to infinite wavelength is larger than the combined electron and atom polarization measured at radio frequency. The difference has been defined as the "phenyl effect" and has been attributed to the mobility at radio frequencies of electrons in the resonance-hybridized orbitals of the aromatic nucleus. It has been suggested that the effect is general for aromatic compounds.
SYNTHESIS OF 1-PHENYLPROPYNE-2,3-13C2
Authors: Renaud R. N. , Leitch L. C.
Published: May 2006

A method of preparing the title compound from methyl-13C iodide through acetophenone-2-13C, 1-phenylethanol-2-13C, styrene-2-13C, styrene-2-13C dibromide, and 1-phenylacetylene-2-13C is described. The overall yield based on methyl-13C iodide was 24%.
MAGNETIC SUSCEPTIBILITIES OF SOME COMPOUNDS OF SILICON
Authors: Lister M. W. , Marson R.
Published: May 2006

Magnetic susceptibility measurements are reported for a number of derivatives of silicon of general formula SiRaHbXc, where R is an alkyl group and X is a halogen. The results are compared with earlier measurements on similar compounds of carbon and show deviations from additivity that can be interpreted in terms of bond interactions. The interactions, in general, are less for compounds of silicon than they are for compounds of carbon.
A STUDY OF HINDERED ROTATION IN SOME PROTONATED BENZYLAMINES
Authors: Reynolds W. F. , Schaefer T.
Published: May 2006

The effect of hindered rotation upon methylene and ammonio proton shifts and coupling constants of eight protonated benzylamines has been determined. It is shown that the necessary and sufficient condition for methylene proton asymmetry in protonated benzylamines is the absence of a plane of symmetry along the C6H5CH2—N bond axis. It is established that the maximum value of the gauche H—C—N—H+ coupling constant is 3.15 c/s and that the minimum value of the trans H—C—N—H+ coupling constant is 9.45 c/s. From the relative values of the rotationally averaged coupling constants, it is established that the steric effect of the substituent decreases in the following order: isopropyl, phenyl > benzyl ≈ ethyl > methyl. It cannot be decided from the available evidence whether the phenyl group or the isopropyl group causes greater steric hindrance.
NEW PHENCYCLONE ADDUCTS FROM ETHYLENIC COMPOUNDS
Authors: Allen C. F. H. , Ning R. Y.
Published: May 2006

not available
THE HYDROGEN–CHLORINE SYSTEM IN THE MM PRESSURE RANGE II. THE VIBRATIONAL GROUND STATE STUDIED BY SELF-ABSORPTION
Authors: Alrey J. R. , Findlay F. D. , Polanyi J. C.
Published: May 2006

Studies of energy distribution among reaction products, through the agency of infrared chemiluminescence, have previously only yielded information concerning the distribution among vibrationally excited states. In the work described here it was shown that self-absorption of the infrared emission could be used as a measure both of the relative and the absolute amount of product present in the vibrational ground state, ν = 0. Two independent methods were used to measure the extent of self-absorption. The first method relied on measurements of an apparent deviation from Boltzmann-type rotational intensity distribution within the ν(1–0) and ν(2–1) bands. The second method depended on measurements of an apparent deviation of the relative intensity of corresponding H35Cl and H37Cl isotopic lines from the natural abundance ratio. (It was shown, at the same time, that the isotopic reactions H + 35Cl2 → H35Cl + 35Cl and H + 37Cl2 → H37Cl + 37Cl have the same rate constant, within ±10%). A third method of measuring the extent of self-absorption, which depends on the detection of an anomaly in the relative intensity of P- and R-branch emission lines is discussed.The self-absorption method was applied to the study of the hydrogen–chlorine system in the 1–2 mm Hg pressure range (see also Part I). Mean partial pressures of HClν=0 ~ 10−2 mm Hg were measured in individual rotational states to an accuracy of ca. ±10%, using an optical path length of 20 cm. The rotational distribution in ν = 0 corresponded to a temperature of 1150 ± 150 °K (the uncertainty in this figure encompasses two independent methods of estimating the self-absorption), as compared with 1300 ± 100 °K for all vibrationally excited states (Part I).
OCCURRENCE OF TRANS-3-HEXADECENOIC ACID IN A SEED OIL
Authors: Hopkins C. Y. , Chisholm Mary J.
Published: May 2006

trans-3-Hexadecenoic acid was found to be a component of the glyceride oil of seeds of Heleniumbigelowii A. Gr. It constituted about 10% of the total fatty acids. The acid was isolated and identified by oxidative cleavage and by its infrared and nuclear magnetic resonance (n.m.r.) spectra. Reaction with alkaline permanganate gave 3-hydroxypalmito-γ-lactone. Mild alkaline treatment of methyl 2 tyrans-3-hexadecenoate caused a shift of the double bond to the 2-position. A sample of Heleniumhoopesii seed oil did not contain any trans-unsaturated acid.
PHOTO-INITIATED REACTIONS OF THIOLS AND OLEFINS: II. THE ADDITION OF METHANETHIOL TO UNCONJUGATED OLEFINS
Authors: Graham D. M. , Mieville R. L. , Pallen R. H. , Sivertz C.
Published: May 2006

Kinetic studies have been made of the addition of methanethiol to ethylene, propylene, and butene-2. The results obtained are consistent with the mechanism postulated for the isomerization reaction (1). The overall activation energy was found to be negative and could be explained in terms of two competing reactions of the adduct radical: thermal decomposition leading to [Formula: see text] and olefin and dehydrogenation of thiol yielding addition product. Only the ratio of the rate constants for these two reactions could be determined. The method of intermittent illumination was used to evaluate the termination rate constant for the combination of two [Formula: see text] radicals which was found to be (2.5 ± 0.7) × 1010 l mole−1 s−1.