bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new hydrate of sodium perborate
Authors: van Gelder D. W. 
Published: September 2010

AbstractA new hydrate of sodium perborate having the composition NaBO3.3H2O, has been discovered. Above 15°C in contact with the saturated solution, it appears to be more stable than the normal commercial salt, NaBO3.4H2O. The preparation of the trihydrate and its most important properties are described.It is indicated briefly how the formation of the trihydrate from the commercial salt is important for the stability of the latter product at slightly raised temperatures.
Tautomerism of hydroxypyridines (I): The structure of 2,4‐dihydroxypyridine
Authors: den Hertog H. J. , Buurman D. J. 
Published: September 2010

AbstractSyntheses of 2‐hydroxy‐4‐methoxypyridine, 4‐hydroxy‐2‐methoxypyridine, 4‐methoxy‐N‐methylpyridone‐2, and 2‐methoxy‐N‐methylpyridone‐4 are described.The ultraviolet absorption spectra of 50% aqueous ethanolic solutions of the above‐mentioned compounds and of 2,4‐dihydroxypyridine and 2,4‐di‐methoxypyridine are measured. Comparison of these spectra enables the determination of the predominant tautomeric structures of 2,4‐dihydroxypyridine and its derivatives.It appears that the chief structure of 2,4‐dihydroxypyridine in aqueous ethanol is that of 4‐hydroxypyridone‐2.Finally it is shown that the methyl derivative of 2,4‐dihydroxypyridine, obtained by Maquenne and Philippea. L. Maquenne and L. Philippe, Compt. rend. 183, 506 (1904). b. Recently E. C. Taylor Jr., Aldo J. Crovetti, and Harvey M. Loux described an analogous synthesis of this substance from an isomer of ricinine ( J. Am. Chem. Soc. 77, 5445 (1955)).
) when heating ricinine with hydrochloric acid solution or by conversion of 4‐methoxy‐N‐methylpyridone‐2 with the same reagent according to Späth and TschelnitzE. Späth and E. Tschelnitz, Monatsh. 42, 251 (1921).
), is 4‐hydroxy‐N‐methylpyridone‐2.
The reaction between silver phosphate and substituted phenoxyacetyl chlorides
Authors: Klaassens K. H. , Schoot C. J. 
Published: September 2010

AbstractThe reaction between silver phosphate and a number of substituted phenoxyacetyl chlorides is described. In all cases liberation of carbon monoxide is observed. After reaction, it is possible in some cases to isolate a substance with the formula R‐O‐CH2‐O‐CO‐CH2‐O‐R (where R represents a substituted phenyl group). The remaining compounds form resins of the phenol‐formaldehyde type but under certain circumstances it is possible to identify an o‐hydroxybenzyl alcohol. A possible mechanism for the reaction is discussed.
Some photochemical properties of alkali salts of aryldiazosulphonic acids
Authors: de Jonge J. , Dijkstra R. 
Published: September 2010

AbstractThe structure of the labile form of an aryldiazosulphonate and the precise result of exposing a stable diazosulphonate to actinic light is considered to be still uncertain.From experiments on the action of light it can be concluded that a stable diazosulphonate is transformed into a product which is in solution at least partly, but possibly completely, dissociated into diazonium ions and sulphite ions.For a number of diazosulphonates the quantum yield for the photochemical reaction has been determined.
Complex coacervation. I. General theoretical considerations
Authors: Voorn M. J. 
Published: September 2010

AbstractSome characteristics of complex coacervation are briefly discussed. A general phase diagram is given, showing the influence of electrolytes on the composition of the two‐phase system at constant charge density and mixing ratio of the two poly‐electrolytes. The applicability of the phase‐rule is discussed.A model for calculations on complex coacervation is proposed, based on the interaction of oppositely charged coils in a sslt solution.
Photochemical acceleration of the hydrolysis of nitrophenyl phosphates and nitrophenyl sulphates
Authors: Havinga E. , de Jongh R. O. , Dorst W. 
Published: September 2010

AbstractNeutral and alkaline solutions in water of the nitrophenyl phosphates are very stable in the dark. These compounds, however, and the meta derivative in particular were found to undergo a remarkable rapid hydrolysis when exposed to visible or ultra‐violet light. The reaction velocity is independent of the hydrogen ion concentration at pH's between 3 and 12 but increases strongly at higher pH's. Nitrophenol and phosphoric acid could be traced as the products of this photochemical reaction. The reaction proved to be zero order; the rate did not change upon varying of the temperature from 25° to 40° C. The nitrophenyl sulphates show an analogous behaviour but for the fact that the increase of reaction rate at higher pH's does not occur and that the difference in the rate of photochemical reaction between the meta compound on the one hand and the ortho and para derivatives on the other hand are even greater than with the phosphates. The experimental evidence points to a purely photochemical (non sensitized) reaction, the nature of which is tentatively discussed.
Méthode d'Obtention Rapide des Indices de Liaison des Hydrocarbures Alternants
Authors: Chalvet O. 
Published: September 2010

AbstractEn utilisant l'idée de classification géométrique des liaisons des hydro‐carbures alternants, on développe une méthode rapide d'obtention des indices de liaison.La méthode est testée par comparaison avec des résultats tirés de la méthode L.C.A.O. dans son application rigoureuse; l'accord obtenu permet de penser que la méthode semble satisfaisante pour le calcul d'indice de liaison en vue d'étude de problèmes concernant la réactivité chimique des hydrocarbures.
Sur la Synthèse de Polyacides Ramifiés par Hydrogénolyse de Composés Thiophéniques
Authors: Buu‐Hoï N. P. , Sy Michel , Xuong N. D. 
Published: September 2010

AbstractOn décrit la synthèse de l'acide 5,5,10,10‐tétraméthyl‐n‐tétradécane‐1,14‐dicarbonique, de l'acide β,β‐diphényladipique, et de l'acide β,β'‐dicarboxyadipique par la méthode de réduction désulfurante de dérivés appropriés du thiophène au moyen de l'alliage de Raney. On montre l'intérêt de cette méthode pour la préparation de polyacides ramifiés difficilement accessibles par d'autres voies.
Synthesis of 1,2‐dehydroderivatives of adrenal cortical hormones
Authors: Szpilfogel S. A. , Posthumus T. A. P. , De Winter M. S. , van Dorp D. A. 
Published: September 2010

AbstractSelenium dioxide dehydrogenation furnishes a method for the introduction of double bonds in ring A of saturated and unsaturated 3‐ketosteroids.
The structures of oxide and hydroxide salts of some tetrapositive ions
Authors: Lundgren Georg 
Published: September 2010

AbstractThe crystal structures of some oxide and hydroxide sulphates or chromates of tetravalent metal ions have been investigated by X‐ray methods. The results show that the crystals contain polynuclear complexes, either infinite or finite. The following types of infinite complexes occur in the crystals:
chains [Me (OH2)2+]n in Th(OH)2CrO4H2O, Th(OH)2SO4, and U(OH)2SO4
chains [MeO2+]n (type I) in TiOSO4H2O
chains [MeO2+]n (type II) in CeOSO4H2O
two‐dimensional, net‐like complexes in zirconium chromates.
Finite complexes, [Me6O4(OH)4]12+, are formed in the crystals of U6O4(OH)4(SO4)6 and Ce6O4(OH)4(SO4)6.In VOSO4(H2O)5, the metal ions do not seem to be joined by oxide or hydroxide bridges, but form mononuclear V‐O6 octahedra.
Komplexbildung in Phosphoroxychlorid
Authors: Gutmann Viktor 
Published: September 2010

AbstractDie geringe Eigenleitfähigkeit des Phosphoroxychlorids beruht auf Eigendissoziation: POCl3 ⇋ POCl2+ + Cl−. Eine Anzahl von Stoffen bildet mit dem Solvens definierte Verbindungen, die das POCl2 +‐Ion enthalten, z.B.: POCl2SbCl6, POCl2AlCl4, (POCl2)2TiCl6. Die Existenz des POCl2+‐Ions in den elektrolytisch dissoziierten Lösungen dieser Stoffe in Phosphoroxychlorid ergibt sich aus ihrem chemischen Verhalten, aus Überführungsmessungen und aus ramanspektrographischen Untersuchungen. Die dadurch ermöglichten Chloridionenübergänge zwischen POCl2+‐Ionen und POCl3‐Molekeln werden für die hohe Überführungszahl dieses Ions verantwortlich gemacht.Säuren des Solvosystems Phosphoroxychlorid treten mit Basen (Chloridionendonoren) zu Chlorokomplexen zusammen, deren Nachweis teils auf präparativem und teils auf konduktometrischem Wege erfolgte. Beispiele hierfür sind: (R4N)2VCl6, (R4N)SbCl6, (R4N) (POCl2) (TiCl6), PCl4SbCl6, oder Al2SnCl10.2 POCl3. Die in den Lösungen vorliegenden Ionengleichgewichte, sowie die Eigenschaften der Chlorokomplexe werden besprochen.
Zur Frage der Bindung in den Cyclopentadienkomplexen mit Übergangselementen
Authors: Fischer E. O. 
Published: September 2010

AbstractIm Zusammenhang mit der Vorstellung eines Eingreifens der gesamten π‐Elektronen der aromatisierten Cyclopentadienylringe in die Elektronenschale der zentralen Übergangsmetalle und des Vorliegens von Durchdringungskomplexen werden Ergebnisse von Hydrierungs‐ und Ozonisierungsversuchen mitgeteilt.Eine Zusammenstellung magnetischer Daten der Verbindungsklasse unter Einbeziehung neu dargestellter, z.B. mit CO, NO, H substituierter Metallcyclopentadienyle wird gegeben und die Verträglichkeit mit der Bindungsauffassung dargetan. Ergebnisse röntgenographischer Untersuchungen werden mitgeteilt.Zur Vorstellung einfach homöopolar gebundener Ringe wird von diesen experimentellen Befunden her Stellung genommen.
Über Interkombinationsspektren von Komplexionen der Übergangsmetalle
Authors: Hartmann H. , Schläfer H. L. 
Published: September 2010

AbstractNach einer kurzen Übersicht über die allgemeinen Gesichtspunkte zur theoretischen Behandlung der Termsysteme der Zentralionen von Komplexen der Übergangsmetalle werden die Ergebnisse quantenmechanischer Überlegungen für die Termsysteme von Ni2+ bei tetraedrischer und quadratisch planarer Anordnung der Liganden mitgeteilt.Weiterhin wird über die Interkombinationsspektren von Mn2+ und Fe3+‐Aquokomplexen berichtet. Die theoretisch ermittelten Termsysteme der Komplexe werden angegeben.
Complexes between tributyl phosphate and inorganic nitrates
Authors: Healy T. V. , Mckay H. A. C. 
Published: September 2010

AbstractMany inorganic nitrates dissolve freely in tributyl phosphate (TBP), forming complexes with the solvent. TBP saturated with uranyl nitrate, for example, corresponds exactly to the composition UO2(NO3)2. 2TBP and has a sharp melting‐point of −6°C; no other complex involving uranyl nitrate and TBP appears to be of any significance. There is only slight ionisation in the TBP phase.A useful general method of determining the number of TBP molecules attached to the inorganic nitrate is by partition experiments between TBP and water. The aqueous phase is kept constant in composition while an inert diluent, e.g. benzene or kerosene, is added to the TBP; the partition of a trace of the inorganic nitrate in question is then measured at a series of dilutions. At high dilutions a limiting law of the form:Partition coefficient ∼ (TBP Concentration)nis obtained, in which the exponent n gives the number of TBP molecules in the complex. The following formulae have been established for different complexes:magnified imageIn all except the first the central atom is co‐ordinated with six groups (O, NO3 or TBP). However in other cases, e.g. the alkali metal nitrates, the co‐ordination number is probably lower.
Stabilities of complex compounds of metals in non‐aqueous solutions
Authors: Burkin A. R. 
Published: September 2010

AbstractBy defining the successive stability constants of metal complex compounds in terms of generalised equilibria it is possible to study metals which do not form simple hydrated metal ions and also non‐water soluble ligands and complexes.If the equilibrium constants are to be interpreted in terms of bond energies etc. it is necessary that the system be defined. That is, the real compositions of the compounds in the equilibrium solution should be known. Some important types of interfering dissociations and reactions can be detected by means of electrical conductivity measurements and some results of such measurements are outlined.The system [PdCl2 (n‐C8H17NH2)2] + PBu3n = [PdCl2 (n‐C8H17NH2) (PBu3n) ] +C8H17NH2 [PdCl2 (n‐C8H17NH2) (PBu3n)] + PBu3n = [PdCl2(PBu3n)2] + C8H17NH2 has been studied and the free energy changes for the replacement of n‐octylamine by tri‐n‐butylphosphine in the two stages are:ΔG1 = −4.56 to −5.08 kcal.ΔG2 =−5.30 to −5.92 kcal.
The exchange of [14C] ethylenediamine with metal‐ethylenediamine complexes
Authors: Wilkins R. G. , Popplewell D. S. 
Published: September 2010

AbstractThe exchange of [14C] ethylenediamine with various metal‐ethylenediamine complexes was studied in aqueous solution. As would be expected from a consideration of the properties of the ions, [Co en3]3+ exchanged very slowly even at 95° C (no exchange in 6 hours at pH = 7 or 12) whereas (Zn en3)2+, [Cu en2]2+ and [Hg en2]2+ exchanged very rapidly at 0° C (within 5 seconds at pH ∼ 11). Although [Ni en3]2+ exchanged rapidly at 0° C (t½ ∼ 5 seconds at pH ∼ 11) the general features of the kinetics were studied. The [Au en2]3+ ion exchanged measurably slowly at 25° C [t½ ∼ 2 hours at pH ∼ 1] and the kinetics of this exchange are being investigated.
The proton complexes of pyrene
Authors: Mackor E. L. , Hofstra A. 
Published: September 2010

AbstractThe basicity constant of an aromatic is one of the main factors determining its partition coefficient over anhydrous HF and n‐heptane.The composition of the conjugate acid formed by the addition of a proton to an aromatic was derived from measurements of the partition coefficient of the aromatic over solutions of NaF in HF and n‐heptane.Pyrene and a few other compounds behave in an exceptional fashion and the mechanism of the reactions involved has been investigated. It was found that this peculiar behaviour is due to the formation of a more complicated ion containing six pyrene molecules and two protons.
Clathrate compounds
Authors: Powell H. M. 
Published: September 2010

AbstractClathrate compounds are those in which two (or more) components are associated without ordinary chemical union through complete enclosure of one molecular kind by a suitable structure formed by the other. There are various related types of molecular compounds frequently referred to as inclusion compounds or by similar names. A limited number of such kinds of molecular compounds has so far been found although the total number of members of the series is very great. Many more are to be expected. Some problems requiring further study include the following:Conditions of formation. Work on related compounds of phenols and on gas hydrates is helpful. In the case of the quinol clathrates there are some difficulties in attaining equilibrium conditions. Some observations on vapour pressures will be discussed.State of the enclosed molecules. Various grades of restriction on motion may arise from their enclosure. Experiments on the electrical, magnetic and other physical properties will be mentioned.Which molecules will form clathrates? Although for a given enclosing structure it is possible by space considerations to predict, within limits, the molecules that can be present as enclosed component, it is more difficult to foresee what is capable of enclosing. Some suggestions will be considered.New structural types of clathrates. A brief mention will be made.
Thermodynamic properties of quinol clathrates
Authors: van der Waals J. H. , Platteeuw J. C. 
Published: September 2010

AbstractThe statistical‐mechanical description of clathrate compounds of quinol with non‐polar gases is discussed on the basis of the Lennard‐Jones and Devonshire model. Formulae are given for the equilibrium vapour pressure of the gaseous component and for the chemical potential of the quinol in the clathrate. From the formulae it appears that the concentration of the gas in a quinol clathrate, which is simultaneously in equilibrium with solid α‐quinol and a gas phase, is independent of the nature of the gas.An experimental method is described for determining the vapour pressure and the composition of the clathrate at the above three‐phase equilibrium. Results are given for the compound with argon. The limited number of experimental data on vapour pressures and heats of mixing at present available seems to support the theory.
A new method of expression of electrokinetic data
Authors: O'Connor D. J. 
Published: September 2010

AbstractThe usefulness of the fundamental electrokinetic ratio ζD/4πη for expression of double layer properties in terms of experimentally measured quantities is discussed and, when electrostatic units are used, the ratio ζD/4πη is shown to have dimensions equivalent to the reciprocal of the e.s.u. magnetic induction or magnetic flux/cm2. It is proposed that the ratio ζD/4πη be assigned the symbol G, and the unit of one (e.s.u. magnetic flux/cm2)−1 be called the Gouy.
A multiple gaschromatographic apparatus for use at temperatures up to 250 °C
Authors: Keppler J. G. , Schols J. A. , Dijkstra G. 
Published: September 2010

AbstractA description is given of an apparatus for the separation of high‐boiling mixtures by means of vapour‐phase chromatography at temperatures up to 250° C. The immobile phase consists of either silicone grease or silicone rubber; the detector is a catharometer working at the same temperatures.
Synthesis and properties of the chlorination products of methyl 4‐amino‐2‐hydroxy‐benzoate. III
Authors: van Der Stelt C. , Nauta W. Th. 
Published: September 2010

AbstractBoth the isomeric chlorination products of methyl 4‐amino‐2‐hydroxy‐benzoate (XIII, P.A.S. methyl ester) with the structure of methyl 1,3,3,5,5,6‐hexachloro‐4‐chlorimino‐cyclohexanone‐2‐carboxylate‐1 (XXIII and XXIV) reacted with an aqueous potassium iodide solution to yield methyl 1,3,5,5,6‐pentachloro‐4‐amino‐cyclohexene‐3‐one‐2‐carboxylate‐1 (XXX). Further reduction converted XXX into methyl 3,5‐dichloro‐4‐amino‐2‐hydroxy‐benzoate (XV). In 2 N sodium hydroxide, one molecule of hydrogen chloride was eliminated from XXX, yielding the yellow product: methyl 1,3,5,6‐tetrachloro‐4‐amino‐cyclohexadiene‐3,5‐one‐2‐carboxylate‐1 (XXXI). Reduction with stannous chloride converted XXXI into methyl 3,5,6‐trichloro‐4‐amino‐2‐hydroxy‐benzoate (XXXII).When reacted with methanolic hydrogen chloride, both the isomers XXIII and XXIV gave an identical reaction product. In view of the fact that the compound did not liberate iodine from a potassium iodide solution, the structure of a dimethyl α‐(1,2,2,4,4,4‐hexachloro‐3‐imino‐butyl)‐α‐chloro‐malonate (XXXIII) was made plausible for this reaction product. Treatment of XXXIII with 2 N sodium hydroxide resulted in the elimination of a molecule of hydrogen chloride. Reduction with stannous chloride converted XXXIII into a pyridine derivative, which is supposed to be a dichloro substitution product of methyl 2‐hydroxy‐6‐methyl‐nicotinate (XXXV) in which the positions of the two chlorine atoms are still unknown.The reaction of XXIV with ethanolic hydrogen chloride led to the formation of two reaction products. One of them is formulated as the diethyl ester homologue of XXXIII (XXXVI), the other one being the methyl ethyl ester homologue (XXXVII). XXXVI was likewise reduced to a 2‐hydroxy‐nicotinic acid derivative.
Total synthesis in the steroid series. I. An tricyclic intermediate to 18‐oxygenated steroids. d,l‐Δ8a‐4bβ‐Methyl‐2β‐formyl‐2α‐(3′‐oxopropyl)‐7‐ethylenedioxy‐4aα,10aβ‐dodecahydrophenanthrene‐4β‐ol‐l‐one)
Authors: Szpilfogelw S. A. , van Der Burg J. , Siegmann C. M. , van Dorp D. A. 
Published: September 2010

AbstractThe total synthesis of racemic aldosterone (I) was achieved recently by J. Schmidlin, G. Anner, J.‐R. Billeter and A. WettsteinA. Wettstein at the XIVth International Congres of Pure and Applied Chemistry, July 1955, Zürich. Experientia 11, 365 (1955).
. Our own efforts in the field of the total synthesis of adrenal cortical hormones and derivatives will be described in the present and forthcoming papersSee Experientia 11, 365 (1955), footnote 2.
Changes in the light‐absorption of intact and killed algal cells upon illumination (Preliminary Communication)
Authors: Spruit C. J. P. 
Published: September 2010

AbstractA comparison of the effects of illumination on the changes in the absorption spectra of intact and killed Chlorella cells between 420 and 600 mμ indicates that several pigment systems contribute to these changes. Some appear to be closely connected with the primary steps of light‐energy conversion, whereas others are more indirectly involved.
Preparation of p,p′‐substituted tetraphenyl‐N,N′‐dimethyl‐thiourea derivatives and investigation into their physiological activity in two fields
Authors: van der Zanden J. M. , de Vries G. , Handelé M. J. 
Published: September 2010

AbstractPreparation of p,p′‐substituted tetraphenyl‐N,N′‐dimethyl‐thiourea derivatives is described.
Studies on vitamin D and related compounds VI: The synthesis and properties of dihydrotachysterol3
Authors: van De Vliervoet J. L. J. , Westerhof P. , Buisman J. A. Keverling , Havinga E. 
Published: September 2010

AbstractWhereas dihydrovitamin D3 I and dihydrovitamin D3 II can be isolated from the mixtures obtained on reduction of cholecalciferol with sodium and alcohols, attempts to obtain dihydrotachysterol3 in a crystalline state from such mixtures were unsuccessful. Pure dihydrotachysterol3, however, could be obtained by reducing tachysterol3 with an excess of lithium in liquid ammonia, concentrating by chromatography on alumina, esterification with phenylazobenzoyl chloride and saponification of the ester. Ultra‐violet and infra‐red absorption spectra are given. The capacity of dihydrotachysterol3 to raise the calcium level of the blood (plasma) proved to be about twice as large as that of dihydrotachysterol2.
The action of p‐toluenesulphonyl chloride on pyridine‐N‐oxide : Preliminary communication
Authors: de Villiers P. A. , den Hertog H. J. 
Published: September 2010

AbstractIt is shown that during the reaction between p‐toluenesulphonyl chloride and pyridine‐N‐oxide, among other substances, N‐(2′‐pyridyl)‐5‐chloropyridone‐2 is formed in a fair yield.
Preparation and constitution of a number of derivatives ofMeta‐di‐Tert. butylbenzene
Authors: Burgers J. , van Hartingsveldt W. , van Keulen J. , Verkade P. E. , Visser H. , Wepster B. M. 
Published: September 2010

AbstractThe synthesis of a number of derivatives ofmeta‐di‐tert.. butylbenzene is described. Wherever the constitution of the compounds obtained did not follow from the method of preparation, it is proved.
Chemistry of acetylenic ethers XVII: The reactions of some ethoxyethynylcarbinols with mercaptans and thio‐acids
Authors: Weiland J. H. Sperna , Arens J. F. 
Published: September 2010

AbstractThe addition of ethyl mercaptan to 1‐ethoxy‐3‐methylbut‐1‐yn‐3‐ol (V) under the influence of peroxides yielded 1‐ethoxy‐2‐ethylmercaptobut‐1‐ene‐3‐ol (VI) in high yield (reaction scheme A). This substance could be rearranged to 2‐ethylmercapto‐3‐methylcrotonaldehyde (VII) (reaction scheme B). The same reaction took place with other mercaptans.The addition of ethyl mercaptan to 1‐(1‐hydroxycyclohexyl)‐2‐ethoxyethyne (XV) and 1‐(1‐hydroxycyclopentyl)‐2‐ethoxyethyne (XVI) under the same conditions yielded 2‐cyclohexylidene‐2‐ethylmercaptoacetaldehyde (XVIII) and 2‐cyclopentylidene‐2‐ethylmercaptoacetaldehyde (XXII) after rearrangement (reaction scheme D).Other thioenol ether compounds were prepared (reaction schemes C and D) starting from the aldehydes VII, XVIII and XXII.Addition of thiobenzoic acid to 1‐ethoxy‐3‐methylbut‐1‐yn‐3‐ol (V) proceeded by a different (probably ionic) mechanism and yielded ‐ after rearrangement and saponification ‐ β,β‐dimethylacrylic acid (reaction scheme E).