bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new spectrophotometric method for the evaluation of complex‐stability constants
Authors: Janssen M. J. 
Published: September 2010

AbstractAn exact spectrophotometric method has been devised for the evaluation of stability constants of metal complexes.This method is developed for complex‐formation in two steps and is especially useful when complex‐formation occurs in acid solutions where the conventional Calvin‐Bjerrum titration method becomes inaccurate. Knowledge of the extinction coefficients of the different species in the solution is necessary.The method has been successfully applied to the determination of stability constants of the complexes of 8‐hydroxyquinoline and 8‐hydroxyquinoline‐5‐sulphonic acid with copper in ethanol/water mixtures.The conditions are examined which must be satisfied in order to obtain accurate results by this method [equations (11) and (15)].
New musk odorants: A new synthesis of polyalkylindans II
Authors: Weber S. H. , Stofberg J. , Spoelstra D. B. , Kleipool R. J. C. 
Published: September 2010

AbstractThe reaction of p‐cymene with tert.amyl alcohol, which yields indans, has been extended to other alcohols and homologues of cymene. It has been found that straight chain secondary alcohols yield substituted cymenes, but secondary alcohols containing a tertiary carbon atom, and tertiary alcohols, yield polyalkylindans. Under the conditions of the reaction cumene does not yield indans.
Chemistry of acetylenic ethers. XXII: Reactions of ethoxyacetylene with formaldehyde and amines
Authors: Arens J. F. , Koerts D. H. , Plieger P. 
Published: September 2010

AbstractEthoxyacetylene I reacts readily with a mixture of aqueous solutions of formaldehyde and non‐aromatic amines yielding ethyl esters of derivatives of β‐aminopropionic acid III instead of “Mannich bases” II.Attempts to prepare the true Mannich bases under anhydrous conditions failed.
Investigations on bongkrekic acid, the toxine from Pseudomonas cocovenenans
Authors: Nugteren D. H. , Berends W. 
Published: September 2010

AbstractReliable methods for the preparation, isolation and determination of bongkrekic acid, the antibiotic from Pseudomonas cocovenenans, are described.Bongkrekic acid (C29H40O7) is shown to be a branched olefinic tricarboxylic acid with a tertiary methoxyl group in a δ‐position with respect to one of the carboxylic acid groups. Seven double bonds are present, forming at least two conjugated systems.A fragment of the structure of the completely hydrogenated bongkrekic acid (C29H54O7) has been elucidated.
Isomerisation of unsaturated fatty acid esters. Part I: The effect of certain catalysts upon the migration of the double bond
Authors: Blekkingh J. J. A. , Janssen H. J. J. , Keppler J. G. 
Published: September 2010

AbstractAn investigation was carried out to study the effect of certain catalysts on the migration of the double bond especially without simultaneous hydrogenation in esters of unsaturated fatty acids. The position of the double bond, before and after isomerisation, was determined by oxidative degradation, followed by chromatographic analysis of the oxidation products.It was observed, that under the influence of a nickel isomerisation catalyst, migration of the double bond to many positions in the chain occurred.
Dimerisation of allylbenzene under the influence of 43% sulphuric acid: (Dimerisation along with isomerisation and hydration; continued)
Authors: van der Zanden J. M. , Rix Th. R. 
Published: September 2010

AbstractPropenylbenzene (III), 1‐phenylpropanol‐2 (II) and 1,3‐diphenyl‐2‐methyl‐ 3‐ethylpropene (IV) are obtained on boiling allylbenzene (I) with 43% sulphuric acid.
The formation of pyrimidinols from α‐acylbenzyl cyanides or α‐acylphenylacetamides
Authors: Wajon J. F. M. , Arens J. F. 
Published: September 2010

AbstractCertain α‐acylbenzyl cyanides are converted into derivatives of pyrimidinol‐4 by heating with a mixture of acetic and sulphuric acids. Scheme A could possibly explain this reaction, but is not entirely satisfactory. According to step 3, the pyrimidinol‐4 is formed by reaction of an α‐acylphenylacetamide with another amide. It is indeed possible to obtain derivatives of pyrimidinol‐4 by such a reaction (scheme B) but only for R′ = phenyl or benzyl. In some cases, a complicated mixture is obtained, due to secondary reactions. One of these, the self condensation of the α‐acyl phenylacetamide, is followed by hydrolytic cleavage of the product to a pyrimidinol‐4 or to a pyrimidine‐diol (scheme C, 2 and 3). Other secondary reactions of a simpler nature occur too. The yields of the derivatives of pyrimidinol‐4 are therefore moderate to low.
The ortho/para distribution of methylol groups in the reaction of phenol and formaldehyde II
Authors: Dijkstra R. , de Jonge J. 
Published: September 2010

AbstractA potentiometric method is described for the quantitative determination of o‐methylol phenol. The method is based on the acidic properties of the complex formed by o‐methylol phenol and boric acid.In the reaction of phenol and formaldehyde, leading to the formation of mono‐methylol compounds, 57‐61% ortho substitution takes place. The distribution of the methylol groups over the ortho and para places of the phenolic nucleus was determined with the aid of the potentiometric method mentioned above.
Determination of the surface tension at 20° C of mineral oil fractions from their ultrasonoric sound velocity and density both measured at 20° C
Authors: Cornelissen J. , Waterman H. I. 
Published: September 2010

AbstractThe surface tension of mineral oil fractions has been determined from their ultrasonoric sound velocity and density. Use is made of a graph with the ultrasonoric sound velocity at 20° C and the density at 20° C, both determined experimentally, as coordinates.For non‐hydrogenated and hydrogenated oil fractions a different graph has to be used, contrary to the determination of the surface tension from kinematic viscosity and density, where one graph was sufficient.
New musk odorants III. Synthesis of several new acetylpolyalkylindans
Authors: Weber S. H. , Kleipool R. J. C. , Spoelstra D. B. 
Published: September 2010

AbstractThe acetyl derivatives of 1,1,2,3,3,5‐hexamethylindan, 1,1,3,3,5‐pentamethylindan and 1,1,3,5‐tetramethyl‐3‐ethylindan prepared previously have been shown to possess musk odour. The hexamethyl compound is the most important of these and has the best properties as a musk substitute. Chloromethylation of the polyalkylindans followed by removal of chlorine by reduction gave a series of methyl‐homologues which were acetylated in the manner described in an earlier publication. These new compounds had less musk odour than the parent ketones.The acetyl group in the acetylpolyalkylindans, having an alkyl group attached to carbon‐5 was found to occupy position 6 in the benzene nucleus.
Hydrocarbures polycycliques aromatiques. III. Dérivés de substitution de l'anthanthrène
Authors: Buu‐Hoï N. P. , Lavit Denise 
Published: September 2010

AbstractIl est montré que l'anthanthrène est formylé par la N‐méthylformanilide en 6‐formylanthanthrène, cet aldéhyde pouvant être réduit par la méthode de Kishner‐Wolff en 6‐méthylanthanthrène. Ce dernier corps peut être à son tour converti en 6,12‐diméthylanthanthrène par l'intermédiaire du 12‐formyl‐6‐méthylanthanthrène; la réactivité des 2 positions méso‐anthracéniques dans la molécule de l'anthanthrène a été en outre mise en évidence par l'action du chlorure de sulfuryle, qui conduit au 6,12‐dichloro‐anthanthrène.
Acid anilides: V. Qualitative separation of fatty acid anilides by paper chromatography
Authors: de Jonge A. P. , Verhage A. 
Published: September 2010

AbstractA new method is described for the qualitative separation and identification of fatty acids in the range C1 to C12 by paper chromatography of their anilides.The basic principles underlying this method are discussed. Use has been made of one of three closely related systems.The location of the spots is determined by means of ultra‐violet absorption measurements.The smallest amount of anilide which can be detected is about 1 μg.
Reactivity of 3,5‐Disubstituted Derivates of Pyridine‐N‐Oxide Towards Sulphuryl Chloride
Authors: den Hertog H. J. , Hoogzand C. 
Published: September 2010

AbstractThe action of sulphuryl chloride on 3,5‐dibromopyridine‐N‐oxide at 120° yields a mixture of chiefly 2‐chloro‐3,5‐dibromopyridine along with a considerable amount of 4‐chloro‐3,5‐dibromopyridine.The conversion of 3,5‐diethoxypyridine‐N‐oxide by the same reagent at lower temperatures results in the formation of a reaction product from which 2,6‐dichloro‐ and 2,4,6‐trichloro‐3,5‐diethoxypyridine‐N‐oxide were isolated.
Dipole moments of α,ω‐disubstituted alkanes
Authors: Ketelaar J. A. A. , van Meurs N. 
Published: September 2010

AbstractThe dipole moments of terms of three series of α,ω‐disubstituted alkanes have been determined in the liquid phase using several methods of calculation. The measurements included the dibromoalkanes, the glycols and the ethyl esters of the dicarboxylic acids. From the resulting moments of the dibromides it is obvious an alternating effect exists for the first members of this series with regard to the influence of temperature. In the other series no definite temperature effect is shown by the different terms, with the exception of the oxalic esters.
Studies on tautomerism VI.): A preliminary communication on the molecular structures of α‐3‐methyl‐6‐chloroquinone‐4‐oxime and 3‐chloroquinone‐4‐oxime in the solid phase
Authors: Romers C. , Shoemaker Clara Brink , Fischmann E. 
Published: September 2010

AbstractIt follows from an X‐ray determination of the crystal structures of “a”‐3‐methyl‐6‐chloroquinone‐4‐oxime and 3‐chloroquinone‐4‐oxime that in the solid state the molecules of these compounds occur in the quinone‐oxime form and not in the tautomeric nitrosophenol form.
Simultaneous transitions in liquid mixtures
Authors: Ketelaar J. A. A. , Hooge F. N. 
Published: September 2010

AbstractSimultaneous transitions were observed in the infra‐red absorption spectra of 19 mixtures; experimental details are given. The influence of the temperature, the mixing ratio and dilution on the intensity of the simultaneous band of CS2 + Br2 is investigated and discussed.
Association of fatty acids in the liquid phase
Authors: Sarkadi D. Szabo , de Boer J. H. 
Published: September 2010

AbstractUsing high paraffins as solvent the association of the fatty acids has been investigated in the liquid phase by an infra‐red spectrophotometric method. Firstly, the association of stearic acid was investigated at temperatures between 40° and 220° C and at concentrations from 0.02 mole/kg up to the pure acid. The degree of association and the equilibrium constants were calculated from the relative intensities. From the temperature dependence of the equilibrium constant a heat of dissociation of 13,400 cal/mole and a standard entropy change of 24 cal/mole × degree could be calculated. Measurements with other fatty acids showed that neither the chain length nor the presence of one or two double bonds, nor the branching of the chain influences the association. The relatively high heat of dissociation and entropy indicate that the high paraffins are very indifferent solvents for the polar parts of the molecular; little or no solvation of these parts occurs.
Investigations on agricultural fungicides. III. The reaction between trichloromethanesulphenyl chloride and benzoic acid)
Authors: Uhlenbroek J. H. , Koopmans M. J. 
Published: September 2010

AbstractA mixed anhydride of trichloromethanesulphenic acid and benzoic acid has been prepared for which we propose the name of benzoic trichloromethanesulphenic anhydride. Some chemical and biological properties of the new compound are described.
Dimerisation ofp‐methylthio‐isopropenyl‐ benzene under the influence of 43 % sulphuric acid
Authors: van der Zanden J. M. , Nieuwenhuis J. , Bos H. J. T. 
Published: September 2010

AbstractOn boiling with 43% sulphuric acidp‐methylthio‐isopropenylbenzene dimerises more slowly than thep‐methoxy‐compound1) and about as rapidly as isopropenylbenzene2) when treated under similar conditions.
Hydrocarbures polycycliques aromatiques. VI. Nouvelles synthèses du 5‐méthylnaphtacène et du dibenzo[a,c]naphtacène
Authors: Buu‐Hoï N. P. , Lavit Denise 
Published: September 2010

AbstractLa réaction de formylation du naphtacène a ét examinée, et une synthèse nouvelle proposée pour le 5‐méthylnaphtacène, consistant en la réduction du 5‐formylnaphtacène. D'autre part, on montre que la ré;action de Friedel‐Crafts entre le triphénylène et le chlorure d′o‐toluoyle conduit au 2‐(2‐méthyl‐benzoyl) triphénylène, et que cette dernière cétone, soumise à la réaction d'Elbs, conduit au dibenzo[a,c]naphtacène.
Electrochemical researches on paraffin membranes I. The specificity of special paraffin membranes as calcium‐ion electrodes
Authors: Tendeloo H. J. C. , Krips A. 
Published: September 2010

AbstractA membrane consisting of a mixture of pure paraffin of low melting point, a calcium salt of low solubility in water and a non‐ionogenic detergent can be used as an electrode for the determination of calcium‐ion concentrations. viz. pCa. Investigations are here reported on solutions of single salts.
Polarography with a stationary platinum plate electrode. Part II: The anodic waves of iodides and bromides
Authors: el Wakkad S. E. S. , Khalafalla S. E. , el Din A. M. Shams 
Published: September 2010

AbstractPrevious reports on the behaviour of iodide solutions when subjected to anodic oxidation are limited and not in agreement. This has been clarified by carrying out the oxidation in solutions of different pH values using the stationary platinum microelectrode and a special technique which applied the potential to the electrode intermittently. The anodic oxidation of the iodide ion produces two well defined waves. The first wave corresponds to a one electron process and is due to the formation of elementary iodine at its reversible potential. The wave height is proportional to the concentration of the iodide ion in solution. The second wave showed irregularities and corresponds to the irreversible formation of iodous acid HIO2. This was concluded from the fact that the height of the wave was roughly four times that of the first wave, and from its dependence on the pH value of the solution. At fairly positive potentials and prior to evolution of oxygen, the wave was found to lose a part of its height, and a minimum appeared in the current which was interpreted by the interaction between the diffusing iodide ion and hydroxyl radicals formed as intermediaries in the evolution of oxygen.Investigations on the bromide ion reveal that it is oxidised in a simple one electron wave to yield bromine. This took place with some overvoltage. The wave height was a linear function of the concentration of the bromide ion in solution.
Electric polarisation of hydrocarbon dinegative ions
Authors: Hoijtink G. J. 
Published: September 2010

AbstractThe influence of a homogeneous electric field on the charge distribution in the di‐negative ions of naphthalene, anthracene, phenanthrene, pyrene, triphenylene, tetrahydroanthracene, tetrahydrophenanthrene and tetrahydro‐triphenylene has been calculated with the aid of a variation treatment and a first order perturbation treatment based on the Hückel m.o. wave functions for the ground and excited states of the unperturbed system. Permanent dipole moments and polarisabilities have been roughly estimated.
The temperature variation of orthobaric density difference in liquid‐vapour systems. I: Normal liquids
Authors: Bowden S. T. , Costello J. M. 
Published: September 2010

AbstractThe chief modifications of the Verschaffelt relation are reviewed, and the generally accepted method of applying the equation is criticised.Analysis of the data for representative non‐associated liquids reveals that the exponent in the equation is specific for each system. Formulated in this way the relation is brought into line with the power laws representing the variation of surface tension and heat of vaporization with temperature and orthobaric density difference, respectively.
The temperature variation of orthobaric density difference in liquid‐vapour systems. II. Water and deuterium oxide
Authors: Costello J. M. , Bowden S. T. 
Published: September 2010

AbstractThe density of deuterium oxide has been determined over the range 20‐200° by means of a sealed‐ dilatometer. The densities above the boiling point are found to be higher than those reported by previous workers.The applicability of the Verschaffelt equation to ascociated systems of the water type has been examined, and it is shown that the exponent has different values for ranges of temperature below and above the boiling point, and is substantially lower than that found for a normal liquid.
Quantitative determination of antioxidants, after chromatographic separation on completely acetylated filter paper. III. Determination of 1. ρ‐(ρ′‐tolylsulphonylamino)phenyl‐ρ‐toluidine; 2. di‐o‐tolylethylenediamine; 3. hydroquinone monobenzyl ether
Authors: Zijp J. W. H. 
Published: September 2010

AbstractMethods are described in this paper for the quantitative determination of three antioxidants in vulcanised rubber. The antioxidants are extracted from the rubber compound, separated by partition chromatography on completely acetylated filter paper and determined colorimetrically by appropriate colour reactions.ρ‐(ρ′‐Tolylsulphonylamino)phenyl‐ρ‐toluidine is oxidised by means of a substituted benzoylperoxide. Both the other antioxidants are coupled with diazotized sulphanilic acid.
Ionylamines I: Synthesis of di‐ and tetra‐hydro‐α‐ and ‐β‐ionylamines and their spasmolytic action
Authors: Kralt T. , Moed H. D. , van Dijk J. 
Published: September 2010

AbstractThe synthesis and properties of amines and quaternary ammonium compounds with the C‐skeleton of ionone and C18‐ketone are described. The spasmolytic activities of the compounds were determined.The results are discussed and it is concluded that these series of amines show a high musculotropic spasmolytic activity. The relationship between the chemical structure and the spasmolytic activity in these series of amines is fairly clear and regular.
Foam stability: Part. II. Gas diffusion in foams
Authors: de Vries A. J. 
Published: September 2010

AbstractPressure differences between foam bubbles of unequal size are the cause of gas transfer from small to larger bubbles. The rate at which the small bubbles decrease in size is calculated as a function of the radius of the bubbles, the surface tension of the liquid and the thickness and permeability of the liquid lamellae between the bubbles. The calculation is based on the assumption that the pressure difference between a small and an adjacent large bubble is dependent only, to a first approximation, on the radius of the smaller bubble.Values of the average lamella thickness calculated by means of the derived rate equation from the observed rate of shrinking of small bubbles in various foams, are of the right order of magnitude, if it is supposed that the permeability of the lamellae is determined by the solubility and the diffusion constant of the gas in the liquid.The rate equation enables the number of bubbles per unit volume of foam to be expressed as a function of time if the initial bubble size frequency distribution is known. It is shown that the bubble size distribution function can be calculated from the bubble sizes observed in the plane of contact between the foam and the glass wall of a container. An experimental method of determining the number and sizes of the bubbles in this plane is described.
On the conversion of kojic acid to 5‐hydroxypipecolic acid, a natural imino‐acid
Authors: Beyerman H. C. 
Published: September 2010

Abstract5‐Hydroxypipecolic acid has recently been found in several plants. A practical synthesis of this acid seemed desirable. In this paper a convenient conversion of kojic acid to 5‐hydroxypipecolic acid and its diastereoisomer is described.
Synthesis of stearoylamino‐acids
Authors: Zeelen F. J. , Havinga E. 
Published: September 2010

AbstractA series of stearoylamino‐acids was synthesized by condensing stearoyl chloride with the esters of the amino‐acids in a two phase system, one of chloroform and one of an aqueous solution of K2CO3 or KHCO3, followed by saponification of the stearoylamino‐acid esters.
Foam stability: Part III. Spontaneous foam destabilization resulting from gas diffusion
Authors: de Vries A. J. 
Published: September 2010

AbstractBubble size frequency distributions in foamed Tee‐pol solutions, oil‐in‐water emulsions and Hevea rubber latex have been calculated from the observed bubble sizes in the plane of contact between the foam and the glass wall of the container. The bubble size distribution in these foams can be satisfactorily described by the same mathematical expression containing one adjustable parameter.Using this expression for the distribution function, a relation is derived between the total number of bubbles per unit area of the cross‐section and the age of the foam, assuming that the disappearance of the small bubbles is caused only by transfer of gas to larger bubbles. With the aid of the derived relationship the average thickness of the liquid lamellae in a number of foams is calculated from the observed rate of decrease in the number of bubbles in the front layer.The calculated values of the average film thickness are of the same order of magnitude as those calculated directly from the observed bubble size distribution and the liquid content of the foam. Additional evidence of the proposed destabilization mechanism is obtained from experiments, in which the nature of the gaseous phase was varied and from comparison of the rate of decrease in the number of bubbles with the rate of shrinking of individual bubbles.
Dissociation and electrical conductance of the sodium, potassium, calcium and magnesium salts of haemoglobin
Authors: van Os G. A. J. , Möller W. 
Published: September 2010

AbstractThe interaction of Na, K, Ca and Mg with bovine and human haemoglobin has been investigated by means of conductivity measurements. It has been found that in unbuffered solutions at pH = 7.8 and protein concentrations from 2.5‐4%, Na, K, Ca and Mg, are not bound by haemoglobin.
Quantitative investigation of the nitration of benzonitrile
Authors: Wibaut J. P. , van Strik R. 
Published: September 2010

AbstractThe nitration of benzonitrile has been investigated at 0°. −9° and −20° and the ratios of the isomers produced, determined quantitatively. The varation of this ratio with variation in the temperature can be represented by Scheffer's formula.Attempts to introduce a second nitro group into p‐nitrobenzonitrile were unsuccessful, this compound being extremely resistant towards nitrating agents.
Studies on vitamin‐D and related compounds VIII: The photoisomerisations of provitamin‐D and its irriadation products. Short communication
Authors: Rappoldt M. P. , Buisman J. A. Keverling , Havinga E. 
Published: September 2010

AbstractResults of kinetic investigations and measurements of quantum yields are reported, which cannot be explained by the most simple scheme imaginable for the photochemical interconversions of provitamin‐D and its isomers. At least two excited transitory species have to be assumed.More experimental data will be needed before a decision can be made in favour of one or other of the hypothetical, more complicated, pathways.