bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methylene Blue Absorption by Montmorillonites. Determinations of Surface Areas and Exchange Capacities with Different Initial Cation Saturations (Clay‐Organic Studies XIX)
Authors: Brindley G. W. , Thompson T. D. 
Published: November 2013

AbstractAbsorption isotherms have been determined for methylene blue absorbed from aqueous solutions on montmorillonites saturated with various cations. Surface areas are determined from observations of the amount of methylene blue absorbed on the clay required to produce optimum flocculation; this condition corresponds to an effective coverage of the surfaces with methylene blue ions. Cation exchange capacities are determined from saturation absorptions. With Li‐ and Na‐saturated clays, the surface areas are approximately 750 m2/g and the exchange capacities agree with values obtained by titration techniques. With K‐montmorillonites, values about 15% smaller are obtained and this is probably due to a small fraction of the clay not expanding beyond about 15Å in water. With M2+‐montmorillonites, a marked difference in behavior is observed between a clay from Wyoming and one from Texas. The Wyoming clay gives much smaller effective flocculation areas and clearly defined saturation absorptions are not obtained. These results are attributed to relatively large particle sizes, so that external surfaces are covered when internal surfaces are only partially covered, and ultimate saturation is hindered by the large particles. With finer particles, the Texas clay gives flocculation areas nearer to those obtained with Li‐ and Na‐clays and the apparent exchange capacities also are nearer to those obtained for the monovalent ion clays. A limitation on surface area measurements for montmorillonites with exchange capacities less than about 100 meq/100 g is discussed.
The Occurrence of Fatty Acids in Fulvic Acid, A Soil Humic Fraction
Authors: Schnitzer M. , Ogner G. 
Published: November 2013

AbstractNormal fatty acids ranging from C14 to C36 were found to account for a maximal 0.10% of the dry ash‐free weight of a water soluble soil fulvic acid. Only 10.0% of the total fatty acids could be extracted by organic solvents from untreated fulvic acid. The remaining 90.0% was extractable only after methylation of the fulvic acid and adsorption on neutral aluminum oxide. While the nature of the molecular forces that hold the fatty acids to the fulvic acid is still a matter of conjecture, evidence was obtained that reduction of hydrogen bonding by methylation was related to the release of fatty acids by the fulvic acid.Ninety‐five percent of the acids that were isolated were saturated, the remaining 5.0% were unsaturated and branched‐cyclic. The C24 acid was the major component. The overall C‐even to C‐odd carbon atom ratio for all acids was 2.3. The results suggested two different origins for the fatty acids: the C14 to C26 acids may be of microbiological origin, whereas the C27 to C36 acids may have arisen from plants.Weight distribution plots of fatty acids and n‐alkanes extracted from the fulvic acid showed an inverse concentration relationship between the two components with identical carbon numbers.The data reported herein suggest that fulvic acid may act as a vehicle for the mobilization, transport and immobilization of water‐insoluble organic compounds—some of which may be serious pollutants—in an aquatic environment.
Debrominative Phosphorylation
Authors: Granoth I. , Kalir A. , Pelah Z. , Bergmann E. D. 
Published: November 2013

AbstractThe reaction of o‐ and p‐brominated diphenyl sulfides with phosphorus trichloride in the presence of aluminium chloride has been investigated. After hydrolysis, the reaction yields p‐substituted arylthiobenzenephosphonic acids and bromide ion. Similar results are obtained with brominated diphenyl ethers. A mechanism for this “debrominative phosphorylation”, involving a stabilized σ‐complex 8, is suggested on the strength of chemical evidence.
Three‐Chromophore Compounds I. Reductive Transformations of the 3,5‐diaryl‐2‐cyclohexen‐1‐ones
Authors: Meyer A. Y. , Schlesinger J. 
Published: November 2013

AbstractThe preparation of three 3,5‐diarylcyclohexanones by rhodiumchlorotris(triphenyl‐phosphine)—catalyzed reduction of the parent olefines (IIa—IIc) is described. Other reducing agents produced several intermediate products of the total hydrogenolysis.
Vibrational Spectra and Thermodynamic Functions of the Three Isomeric Methoxyphenols
Authors: Verma V. N. , Nair K. P. R. , Rai D. K. 
Published: November 2013

AbstractInfrared absorption spectra in the range of 250‐4000 cm−1 of the three isomeric methoxyphenols are reported. The para methoxyphenol is in the solid phase at room temperature and its spectrum has been investigated in the range of 700‐4000 cm−1 in chloroform solution in addition to the spectrum recorded for its nujol mull. Under the usual approximation of the two substituent groups taken as point masses the observed bands have been assigned to different modes of vibration. These assignments have been used to calculate the molar thermodynamic functions for these compounds.
Electrocatalytic Oxidation of Amines on Platinum Electrodes. Part III. Oxidation Of Ethylenediamine Via Higher Oxidation States of Nickel
Authors: Fried I. , Meyerstein D. 
Published: November 2013

AbstractThe voltammetric behaviour of aqueous nickel ethylenediamine solutions has been studied. Electrocatalytic oxidation waves were obtained which are attributed to the formation of trivalent and possibly also tetravalent nickel ethylenediamine complexes as intermediates. The mechanism of the electrocatalytic process is discussed.
ESR Study of Cerium (IV) Oxide in Vacuum Air and Hydrogen
Authors: Steinberg M. 
Published: November 2013

AbstractCerium (IV) oxide prepared at high temperatures in air shows ESR absorption signals. The oxide prepared at low temperatures shows very diffuse signals. Heating the oxide in vacuum at 1000° or in hydrogen at 298° results in a reduction of the intensity of the signal. A theory was developed to show that the ESR signal is obtained from the quasi free electron in non‐stoichiometric ceria.
Thiohydrolysis of 6‐Methylthio‐8‐Azapurines (7‐Methylthio‐1,2,3,4,6‐Penta‐Azaindenes) Bearing a Methyl Substituent in the Triazole Ring
Authors: Bergmann F. , Rashi M. , Reichman U. , Neiman Z. 
Published: November 2013

AbstractIn 8‐azapurines, the 1,2,3‐triazole ring can assume three tautomeric forms. The corresponding 7‐, 8‐ and 9‐ methy1‐6‐methylthio derivatives all underwent rapid thiohydrolysis to the respective 6‐thio‐8‐azapurines, when treated with ammonium sulfide at room temperature. The high reactivity of the 8‐methyl derivative was anticipated on the basis of its o‐quinonoid structure. However, thiohydrolysis of 7‐ and 9‐ methyl‐6‐methylthio‐8‐ azapurine is unexpected and contrasts sharply with the refractoriness of 7‐ and 9‐ methyl‐6‐methylthiopurine.
Nephelometric Measurements by Use of a Spectrofluorometer. Part I: (A) Determination of Sulphate; and (B) Determination of Calcium
Authors: Gonen L. , Cogan E. 
Published: November 2013

AbstractAn approach to quantitative nephelometric measurements using a spectrofluorometer is presented. The measurements are performed with the aid of a monochromatic filter, which is transparent for the line 546 nm and by adjusting the monochromator for the same wavelength. The method was applied for the determination of micro amounts of: (1) sulphate as barium sulphate in colorless or colored aqueous solutions, in phosphoric acid, in the presence of large amounts of iron and in ores; is also suitable for determination of total inorganic sulfur after oxidation to sulphate and in organics after combustion; (2) calcium as calcium naphthalhydroxamate in aqueous and phosphoric acid solutions; and (3) calcium in the presence of large amounts of magnesium. The proposed technique has proved useful for quantitative nephelometric determinations in colored solutions. The high sensitivity also permits the use of micro samples.
Reactions of ReF7 and ReOF5 with Fluoride Ion Donors
Authors: Selig H. , Karpas Z. 
Published: November 2013

AbstractReactions of ReF7 and ReOF5 with NOF and NO2 F yielded the compounds NO+ReF8−, NO2+ReF8−, NO+ReOF6− and NO2+ReOF6−. Raman spectra of the solids and NMR spectra of solutions in anhydrous HF show that the complexes are ionic and give tentative indications that ReF8− has D4d symmetry and ReOF6− has C5v symmetry.
Synthesis of Some Polymeric Dyes
Authors: Tahan M. , Perez D. , Zilkha A. 
Published: November 2013

AbstractPolymeric dyes derived from 4‐vinyl phthalic acid and 2,2′‐divinyl benzidine were prepared. Diethyl 4‐vinyl phthalate was synthesized as follows: The Diels‐Alder reaction between 2‐ethyl butadiene and dichloromaleic anhydride led to the formation of 4‐ethyl phthalic anhydride which was esterified, α‐brominated in the side chain by NBS, and dehydro‐brominated by heat. The resulting monomer was polymerized and polydiethyl 4‐vinyl phthalate was reacted with phenol and resorcinol to yield “polyphenolphthalein” and “polyfluorescein” respectively. 2,2′‐Divinyl benzidine was diazotized and coupled with naphthionic acid, anthranilic acid and N,N′‐dimethylaniline respectively, but the resulting vinylic dyes did not polymerize due to steric reasons. However, polymeric dyes were obtained by homopolymerizing, or copolymerizing, 2,2′‐divinyl benzidine with vinyl monomers, diazotizing the corresponding soluble polymers and coupling them with the above reagents. All the polymeric dyes exhibited indicator functions, changing their colour in basic or acidic media.
The Use of Amberlyst Ion‐Exchanger in the Picolyl Ester Method of Peptide Synthesis
Authors: Burton J. , Young G. T. 
Published: November 2013

AbstractThe use of Amberlyst‐15 ion‐exchanger (as the 3‐bromopyridinium salt) for the separation of coupling product in the picolyl ester method of peptide synthesis is exemplified by a description of the synthesis of N‐butoxycarbonyl‐O‐benzyl‐L‐seryl‐S‐benzylthiomethyl‐L‐cysteinylglycyl‐L‐phenylalanine 4‐picolyl ester, in 76.5% overall yield, from phenylalanine 4‐picolyl ester dihydrobromide.
Synthetic Peptides Related to Horse Heart Cytochrome C V. Peptides Corresponding to Positions 94–104
Authors: Wolman Y. , Klausner Y. S. 
Published: November 2013

AbstractSynthesis is described of a series of peptide derivatives which corresponds to positions 94‐104 in the primary structure of horse heart Cytochrome C. The preparations of the C terminus undecapeptide derivative α ‐benzyl‐L‐leucyl‐L‐isoleucyl‐L‐alanyl‐O‐benzyl‐L‐tyrosyl‐L‐leucyl‐Nϵ ‐trifluoroacetyl‐L‐lysyl‐Nϵ‐trifluoroacetyl‐L‐Lysyl‐L‐alanyl‐L‐threonyl‐L‐asparaginyl‐γ‐benzyl‐L‐glutamate trifluoroacetate and the C terminus nonapeptide L‐alanyl‐L‐tyrosyl‐L‐leucyl‐L‐lysyl‐L‐lysyl‐L‐alanyl‐L‐threonyl‐L‐asparaginyl‐L‐glutamic acid is described.
N‐Alkylation During the Removal of a Carbamate‐Type Protecting Group
Authors: Sheradsky T. , Salemnick G. , Frankel M. 
Published: November 2013

AbstractAcidolysis of 2‐(p‐biphenylyl)isopropyl N‐(5‐nitro‐2‐pyridyloxy)carbamate (IV) resulted in loss of carbon dioxide and formation of N‐2‐(p‐biphenylyl)isopropyl‐O‐(5‐nitro‐2‐pyridyl) hydroxylamine (V). The mechanism of this unusual reaction is discussed.
Reactive Species Mutually Isolated on Insoluble Polymeric Carriers. II. The Alkylation of Esters
Authors: Kraus M. A. , Patchornik A. 
Published: November 2013

AbstractPolymer esters of the type magnified image have been alkylated by the use of trityllithium and an alkyl halide. The sole product obtained was that of monoalkylation. No self condensation occurred due to the immobilizing effect of the polymeric carrier.
Palladium Catalysed Reaction of Myrcene with Acetic Acid and Phenol
Authors: Watanabe S. , Suga K. , Hijikata K. 
Published: November 2013

AbstractThis paper concerns the reaction of myrcene, 7‐methyl‐3‐methylene‐1,6‐octadiene, with acetic acid‐sodium acetate and phenol‐sodium phenoxide in the presence of a variety of palladium‐catalysts under various conditions. The reaction of myrcene with acetic acid catalysed by palladous chloride‐triphenyl phosphine in benzene under nitrogen gave a mixture of linalylacetate (I), 2‐acetoxy‐3‐methylene‐7‐methyl‐6‐octene (II), 3‐acetoxymethyl‐7‐methyl‐2,6‐octadiene (III), nerylacetate (IV) and geranylacetate (V) in yield of 15%. The analogous reaction catalysed by palladium‐cupric acetate under oxygen gave the similar acetates mixture in yield of 21%. The reaction of myrcene with phenol catalysed palladous chloride‐benzonitrile complex gave a mixture of various terpene ethers and myrcene dimers.
Infrared Spectra and Surface Reactions of HCl, DCl and Cl2 Adsorbed on Germanium
Authors: Lubezky A. , Folman M. 
Published: November 2013

AbstractAdsorption of HCl, DCl and Cl2 on high surface area germanium films was studied by means of IR absorption spectra. The films were prepared by high temperature evaporation of germanium in a helium atmosphere. On adsorption of HCl and DCl two main absorptions appeared at 460 cm−1 and 408 cm−1 and additional weaker bands at 2050 cm−1 and 2920 cm−1 (with HCl) and at 1313 cm−1 (with DCl). The spectra indicate that both gases undergo dissociation on adsorption. In the case of Cl2 the bands at 460 cm−1 and 408 cm−1 appeared in the spectrum; here again strong evidence exists that dissociative adsorption takes place. Mass spectrometer analysis showed that the desorption product consists mainly of GeCl4.
Preparation and Properties of Tricyclopentadienyl Cerium (IV) Chloride and Bisindenyl Cerium (IV) Dichloride
Authors: Kalsotra B.L. , Multani R.K. , Jain B.D. 
Published: November 2013

AbstractThe reactions of dipyridinium cerium (IV) hexachloride with tetracyclopentadienyl cerium or sodium cyclopentadienide and tetraindenyl cerium or sodium indenide in tetrahydrofuran yield tricyclopentadienyl cerium (IV) chloride and bisindenyl cerium (IV) dichloride. Infrared spectra, thermal stabilities and other characteristics of the compounds have been studied.
Uranium (VI) Complexes of Some Tridentate Schiff Bases
Authors: Mehta R.K. , Gupta R.K. , Singhi V.C. 
Published: November 2013

AbstractProtonation constants (log KH1 and log KH2) of N‐acetylacetoneanthranilic acid (abbr. H2 AA), N‐salicylideneanthranilic acid (abbr. H2SA) and N, (2‐hydroxy‐1‐naphthalidene) anthranilic acid (abbr. H2 NA), and formation constants of their uranium (VI) complexes have been determined potentiometrically in 50% dioxan (vol/vol) solutions (μ = 0.1 M NaClO4) at 30 ± 0.1°C. The stabilities of these complexes were found to be in the order: UO2+2‐H2NA > UO2+2‐H2SA > UO2+2‐H2AA.
Light Scattering of Montmorillonite in NaCl and Na‐Phosphate Solutions Subjected to Pulsed Electric Fields
Authors: Lahav N. , Raziel S. , Pecht I. 
Published: November 2013

AbstractChanges in scattered light of fresh and aged sodium montmorillonite, suspended in sodium chloride and phosphate solutions after application of very short and strong electrical fields, was studied. Montmorillonite suspensions behave like polydispersed systems. Results of phosphate treated montmorillonite were compared with phosphate‐free montmorillonite, in which a flocculation process took place. The range of particle size for the phosphate treated montmorillonite was calculated.
On the Direct Spectrographic Analysis of Steels for Boron
Authors: Schoenfeld Irena 
Published: November 2013

AbstractThe possibility of direct spectrographic analysis for the routine determination of boron in steels in the range 10–150 ppm was investigated. The procedure was worked out that requires no specialized equipment, is rapid and simple, and suitable for routine control analyses when precision is not of prime importance. The method uses DC‐arc excitation of the samples in the form of powder or chips, with LiF added both as buffer and volatilizing agent. The electrodes are deep, with large capacity so that they can hold samples of about 150 mg, as the use of a large sample lowers the detection limit. The analytical line used is BI 2089.6 Å and the spectra are recorded on Ilford Q‐2 plates. One of the results of this work is a correction of the wavelength of the BII 3451 Å line.
Some Calculated Standard Free Energy Changes During Chemical Weathering of Rock‐Forming Silicates
Authors: Yariv S. 
Published: November 2013

AbstractStandard free energy changes of dissolution and hydrolysis of rock‐forming silicates and those of leaching of soluble cations from the same silicates were computed. Correlation between the sequence of Goldich and the order of changes of standard free energies was observed only in the dissolution process. It seems that chemical weathering is governed mainly by aqueous dissolution.
The Luminescence of Some Luminol Oxidation Products
Authors: Nikokavouras J. , Perry A. , Vassilopoulos G. 
Published: November 2013

AbstractThe oxidation of luminol with t‐butyl hypochlorite and the fluorescence and chemiluminescence of some of the products are herein reported. The fluorescence was studied in the present work as a function of pH and the spectral distribution was then recorded at the pH of maximum fluorescence intensity; the chemiluminescence spectrum was obtained under the conditions of the luminol‐chemiluminescence.
Preparation, IR, UV, NMR, and Mass Spectral Fragmentations of New Substituted Phenoxaphosphinic Acids
Authors: Levy J. B. , Whitehead G.W. , Granoth I. 
Published: November 2013

AbstractThe synthesis and IR, UV, NMR; and mass spectral fragmentations of substituted phenoxaphosphinic acids I – XIV are reported. A diazo method gave I, and the Friedel‐Crafts method II – XIV. Infrared assignments: POH, broad bands, 2600, 2250, and 1650; C‐P, 1490 ‐ 1440; C‐O, 1280 ‐ 1260; P=0, 1190 ‐ 1140; and P‐O, 978 ‐ 974 cm−1. Characteristic bands also occur at 1330 ‐ 1320 and 1230 ‐ 1210 cm−1. The UV spectra possess maxima at 210 ‐ 220 mμ (log ∈ 4.50 ‐ 4.60), 240 ‐ 250 (4.20 ‐ 4.30), and 298 – 304 (3.65 – 3.75). The NMR spectra give τ 7.56 ppm for a 2‐methyl substituent, 7.48 for a 4‐methyl and a quartet at 7.26 and a triplet at 8.71 (J = 7.7 Hz) for a 2‐ethyl. The chemical shifts were virtually unaffected by alkyl or halogen substituents on the other aromatic ring but were shifted upfield by ortho or meta methyl substituents on the same ring. Singlets at τ 7.44 and 7.60 ppm in the spectrum of VIII gave calculated base values of about 7.28 and 7.44 for a 1‐methyl and 3‐methyl, respectively. The mass spectra are greatly influenced by the substituents. All showed loss of PO2H from the molecular ion or in the case of ethyl compounds after CH3· expulsion. CHO or CCIO was then eliminated. The molecular ions of methyl compounds eliminated H2O.
2‐Azabicyclo [3.2.0] Heptane‐3‐One
Authors: Nativ E. , Rona P. 
Published: November 2013

Abstract2‐Azabicyclo [3.2.0] heptane‐3‐one was synthesized by the reaction of cyclopentene and chlorosulphonyl isocyanate. The structure of the product was established by its hydrolysis to cis‐2‐amino‐cyclopentanecarboxylic acid.
Absolute Intensities and the Chemical Objectives of Charge Density Studies by Diffraction Methods
Authors: Coppens Philip 
Published: November 2013

AbstractIt is shown that an experimental measurement of the absolute scale is highly desirable for the quantitative measurement of atomic form factors and, more generally, electron distributions in crystals. The experimental scale‐factor measurement on the mineral kernite confirms that atomic orbitals in molecules are contracted relative to isolated‐atom orbitals. Objectives of charge‐density measurements are divided into direct analysis of the charge density and the analysis of derived quantities, such as net atomic charges, dipole moments and the ionic character of bonds.
Organic Carbonates. Part XIII. Separation of Polar and Steric Effects in the Hydrolyses of Substituted Ethylene and Trimethylene Carbonates
Authors: Katzhendler Joshua , Poles L. A. , Sard Shalom 
Published: November 2013

AbstractThe rate constants, the free energies (ΔF#), the energies (ΔH#) and entropies (ΔS#) of activation, and the steric parameter of substituent (Es), for both the acid and the alkaline hydrolyses of four highly branched ethylene carbonates (Ia ‐ d), and 11 trimethylene carbonates (IIa ‐ k) were analysed according to Taft's procedure for a quantitative separation of polar and steric effects of alkyl substituents in the total effect of structure upon reactivity in hydrolysis. Application of Eq. (II) with Σσ* to the most hindered substrates (“α‐axial methyl effect”) (IId ‐ f) and to the moderately hindered substrates (IIa ‐ c) gave well‐separated parallel straight lines for the two groups. Deviations from Eq. (II) were manifested by the rate‐enhanced group of compounds, geminally 2,2‐disubstituted trimethylene carbonates (IIg ‐ k) (“2,2‐gem‐dialkyl effect”), shown to exert a polar “field effect”; the assessment of its substituent constant σF* (= +0.17) is provided by Eq. (III). Analysis of 018 exchange experiments and ΔΔFA# vs ΔΔFB# correlation (Eq. (IV)) show that the acid‐ and base‐catalysed reactions occur in parallel via similar transition states, the attainment of each designating the rate‐determining step in both systems. A value of 0.5 kcal/mole was found for the net steric interaction (ESB ‐ ESA) exerted by an α‐axial methyl substituent on the attacking hydroxide ion in attaining the transition state. It was concluded that in alkaline hydrolysis, the transition states of compounds exhibiting an “α‐axial methyl effect” should closely resemble the tetrahedral intermediate (IX), while the transition states of the 2,2‐gem‐dialkyl series should more closely resemble the ground‐state.
The Crystal and Molecular Structure of Kinamycin C p‐Bromobenzoate
Authors: Furusaki Akio , Matsui Masanori , Watanabé Tokunosuké , Ōmura Satoshi , Nakagawa Akira , Hata Tōju 
Published: November 2013

AbstractThe molecular structure of kinamycin C has been determined by means of an X‐ray study of its p‐bromobenzoate derivative, C31H23N2O11Br. The crystals are monoclinic, P21, with four molecules of the derivative and four molecules of benzene in a unit cell of dimensions: a = 18.404 ± 0.005, b = 21.299 ± 0.004, c = 9.049 ± 0.001 Å, and β = 90.07 ± 0.03°. Reflection intensities were measured visually from equi‐inclination Weissenberg photographs taken with Cu Ka radiation. The structure was solved by the heavy‐atom method, and was refined by the block‐diagonal‐matrix least‐squares method using anisotropic temperature factors for all the atoms. The final R factor is 8.9%. The stereostructures of the two crystallographically independent molecules are almost identical. The skeleton of the molecule is made up of four fused rings: two of these form a 1,4‐naphthoquinone system and the rest are a pyrrole and a cyclohexene ring. A cyano group is bonded to the nitrogen atom of the pyrrole ring, which is rather unusual in an antibiotic.
The Use of a Gel‐Filtration Procedure to Study the Interaction Between Inorganic Phosphate and Alkaline Phosphatase
Authors: Kaufman H. W. , Kleinberg I. 
Published: November 2013

AbstractA gel‐filtration procedure has been used to examine the effects of pH, ionic strength, enzyme concentration, and concentration of inorganic orthophosphate (Pi) on the molecular interaction between alkaline phosphatase and Pi. At pH values above the isoelectric point of the enzyme, repulsion was demonstrated; this was reduced under those conditions favouring a reduction in the effective negative charge on either or both enzyme and phosphate molecules. In addition to providing information on the interaction between Pi and enzyme, the study demonstrates that the gel‐filtration procedure can be used to study repulsion between molecules. Earlier it was shown that it could be used to study attraction.