bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of crystalline organic compounds by means of X‐ray analysis
Authors: de Lange J. J. , Houtman J. P. W. 
Published: September 2010

AbstractSimple comparison of X‐ray diagrams of crystalline organic derivatives can be a very useful method for identification purposes.The X‐ray patterns of the 2,4‐dinitrophenylhydrazones of several carbonyl compounds and of the 3,5‐dinitro benzoic acid esters of some alcohols were compared using Astbury's recording technique.The differences in melting point of several samples of the 2,4‐dinitrophenylhydrazone of acetaldehyde are not due to different crystal structures, but are merely the result of irremovable contaminations.
Untersuchungen über indolderivate. X . Einige von 2,3‐Dimethylindol abgeleitete Bz‐Carbonsäuren
Authors: Verkade P. E. , Lieste J. 
Published: September 2010

AbstractEs wird die Synthese der vier theoretisch möglichen 2,3‐Dimethylindol‐Bz‐carbonsäuren, ausgehend von Methyl‐α‐bromäthylketon und einem aminobenzoesauren Ester, beschrieben.
On the structure of leucaenine (leucaenol) 3rd communication
Authors: Wibaut J. P. , Kleipool R. J. C. 
Published: September 2010

AbstractN‐methyl‐3‐hydroxypyridone‐4 has been synthesized from meconic acid and methylamine. This synthetic product is identical with the N‐methyl‐hydroxypyridone that has been obtained by Bickel and Wibaut as a decomposition product from leucaenine (leucaenol).
Properties and constitution of the peroxides prepared oxidizing propane and their analysis
Authors: Kooijman P. L. , Ghijsen W. L. 
Published: September 2010

AbstractThe present publication describes the experimental facts which led to the assumption that the aqueous peroxide solutions formed by incomplete oxidation of propane consist mainly of a mixture of hydrogen peroxide and the lower aldehydes and their association products, the hydroxyalkylhydro peroxides and the dihydroxyalkyl peroxides.Further an analytical method is given for the determination of the total active oxygen content; for the determination of the free hydrogen peroxide content a method has been worked out yielding the approximate content. Moreover, the values obtained by this method are compared with the free hydrogen peroxide content calculated from the equilibrium constants.
The system NH4NO3  AgNO3  Pb(NO3)2  H2O
Authors: Dingemans P. , Dijkgraaf L. L. 
Published: September 2010

AbstractAs a continuation of a number of previous investigations of the binary combinations of the salts NH4NO3, AgNO3 and Pb(NO3)2, the meltingpoint diagram of the ternary system has now been studied. The ternary eutectics were of special interest.Furthermore the vapour pressures of the following systems were measured:
solutions in water saturated with respect to Pb(NO3)2 + NH4NO3. AgNO3 + NH4NO3 from 10°C to the ternary eutectic at 97.4°C.
solutions in water saturated with respect to Pb(NO3)2 + NH4NO3. AgNO3 + AgNO3 from 10°C to the ternary transition point at 107.9°C.
These are the first cases in which the entire course of the vapour‐pressure line has been measured for solutions saturated with respect to three salts. Both lines show the customary form with a maximum, many cases of which are already known for solutions saturated with respect to one or two salts.For these quaternary systems also, the relative vapour‐pressure line was also found to be almost straight, as had already been found in this laboratory for several binary and ternary systems.A formula for the calculation of the maximum in the vapour‐pressure line, previously derived for solutions saturated with respect to one salt, was also found to be applicable to these solutions saturated with respect to three salts.
Des Quinoléines Substituées: VI. Dérivés macrocycliques de la quinoléine
Authors: Hoï Ng. Ph. Buu‐ , Royer René 
Published: September 2010

AbstractDans le présent mémoire, il est montré que les cyclanones à très grand cycle peuvent réagir avec l'isatine et ses homologues dans les conditions de la réaction de Pfitzinger. Les acides cinchoniniques substitués en positions 2 et 3 par un grand cycle qui prennent ainsi naissance fournissent par décarboxylation des quinoléines macrocycliques, non odorantes.
Untersuchungen über Indolderivate. XI: Die Reaktion zwischen Monobromacetaldehyd‐diäthylacetal und primären und sekundären aromatischen aminen
Authors: Janetzky E. F. J. , Verkade P. E. , Meerburg W. 
Published: September 2010

AbstractEs wird die Reaktion zwischen Monobromacetaldehyd‐diäthylacetal und primären und sekundären aromatischen Aminen untersucht. Dabei tritt das Arylaminoacetaldehyd‐diäthylacetal als primäres Produkt auf. Zwei neue Methoden zur Darstellung derartiger Substanzen werden beschrieben. Es gelang nicht hiervon ausgehend Indol bezw. Indolderivate zu erhalten.
The taste of 1‐alkoxy‐ and 1‐halogeno‐2‐amino‐4‐cyano‐benzenes
Authors: Blanksma J. J. , Petri E. M. 
Published: September 2010

Abstract3‐Nitroaniline is 40 times and 3‐cyanoaniline 25 times as sweet as cane sugar. The taste of their derivatives, the 1‐alkoxy‐ and 1‐halogeno‐2‐amino‐4‐nitrobenzenes, which are very sweet, are now compared with those of the 1‐alkoxy and 1‐halogeno‐2‐amino‐4‐cyanobenzenes, which are also very sweet substances. The sweet taste diminishes when the nitro group is replaced by the cyano group. When the cyano group is hydrolysed to amido the sweet taste disappears.
Some properties of the ecgonines and their esters. VI. The calcium and lead salts of l‐ecgonine, the conversion of l‐ecgonine into l‐benzoylecgonine and its esterification with methyl alcohol and benzoic anhydride or benzoyl chloride
Authors: de Jong A. W. K. 
Published: September 2010

AbstractThe calcium salt of l‐ecgonine is soluble in methyl and ethyl alcohols and also in anhydrous benzene. It crystallises in fine needles. Ecgonine forms a compound with calcium chloride.The lead salt also crystallises in needles and is readily soluble in alcohol and benzene.An almost complete conversion of l‐ecgonine into l‐benzoylecgonine is obtained in 5 days at ordinary temperature in aqueous acetone with the addition of 2–3 times the theoretical quantity of benzoic anhydride.By the action of benzoic anhydride and methyl alcohol on benzoylecgonine at ordinary temperature the anhydride of benzoylecgonine is formed as the main product, which can then give cocaine and benzoylecgonine with methyl alcohol. The conversion into cocaine obtained, however, by using 7 times the theoretical quantity of benzoic anhydride was only 80%.Benzoylecgonine when treated with methyl alcohol and 3.5 times the theoretical quantity of benzoyl chloride at ordinary temperature gives an almost complete conversion into cocaine.
Investigations concerning polymerization of propene and ethene induced by various substances
Authors: Kooijman P. L. , Ghijsen W. L. 
Published: September 2010

AbstractThis publication presents a description of an experimental investigation on the induced polymerization of propene and ethene at an initial pressure of ∼ 250 at and at temperatures of 280‐375°C. A series of substances belonging to the metal alkyls, azo‐ and diazo compounds, nitro compounds, oximes and hydrazine derivatives, was found to accelerate the polymerization of these olefines.With some exceptions, the polymerizing action of these substances is greater on ethene than on propene.An investigation at varying reaction temperatures with some substances representing the above groups, showed that the initiator yield (i. e. the quantity of olefines in gmol polymerized under the influence of 1 gmol of the initiator) is probably determined by the number of free radicals formed per molecule in the thermal decomposition of these substances. At higher temperatures, the initiator yield decreases.It was also found that the action of the above substances was not influenced when the wall surface area is increased by a factor of 6 by filling the autoclave with splintered glass. Impurities, such as water, sulphur and lubricating oil, when present in small quantities, have no appreciable influence on the reactions.The available factual material hardly enables us to make any definite statements on the actual mechanism of these induced chain reactions.
Vapour pressures and heats of vaporization of cis‐ and trans‐1,2‐dichloroethene
Authors: Ketelaar J. A. A. , van Velden P. F. , Zalm P. 
Published: September 2010

AbstractVapour pressures of cis‐ and trans‐1,2‐dichloroethene have been measured over a temperature range from zero‐point up to about 90°C, using glass spring tensimeters of the type, applied in this laboratory for all determinations of this kind. Special care was taken in purifying the samples of the two isomers. Dielectric constant measurements were carried out in order to control the degree of purity of the samples. The values of the vapour pressures obtained are compared with those, determined by some authors in the past. Heats of vaporization and Trouton constants are derived from the measurements.
On the electrometric determination of vanadium in steels
Authors: Claassen A. , Corbey J. 
Published: September 2010

AbstractProcedures are given for the electrometric determination of vanadium in alloy steels. In tungsten‐free steels vanadium is determined by titration with ferrous sulphate under specified conditions of acidity. It is shown that this method gives low results for steels containing tungsten, due to the incomplete reduction of the vanadophosphatotungstate complex; complete reduction however takes place by boiling with excess ferrous sulphate, enabling the determination to be finshed by electrometric titration with standard permanganate. Small amounts of vanadium accompanied by large amounts of tungsten can only be determined by titration with ferrous sulphate when the amount of phosphoric acid is greatly increased.
Röntgenographic observation of the ripening of silver bromide emulsions
Authors: Burgers W. G. , Kooy J. N. 
Published: September 2010

AbstractDebye‐Scherrer photographs of silver bromide emulsions were taken before and after the emulsion had undergone a “ripening‐process” by keeping it at a temperature of about 40° C for a few hours. An increase of resolution of the Co‐Kα‐doublet of the AgBr‐line σ(H2 + K2 + L2) = 40 confirmed that the ripening‐process was accompanied by growth of the silver bromide crystals. It was further shown that this crystal growth took place in the first stage of the ripening‐process, before the soluble salts had been eliminated by rinsing.
Preparation and properties of 1,4‐dihydrobenzene and of the addition and substitution products produced from it by the action of bromine
Authors: Wibaut J. P. , Haak F. A. 
Published: September 2010

Abstract1,4‐Dihydrobenzene has been obtained by reducing benzene by the method of Wooster and has been prepared in a pure state; the structure of this hydrocarbon is apparent from the formation of malonic acid and benzoquinone on oxidation. Some of its physical constants have been determined. The addition products with bromine. C6H8Br2 and C6H8Br4, are described.
Some properties of hydrocarbons having more than twenty carbon atoms
Authors: Mazee W. M. 
Published: September 2010

AbstractThe heat of fusion, heat of transition, specific heat, molecular refraction calculated by means of the Lorentz‐Lorenz equation, boiling point under reduced pressure, heat of evaporation and viscosity are given for a number of normal and branched alkanes and a cyclane, all having more than 20 carbon atoms.The crystallographic properties of n‐heneicosane and n‐tetracosane at different temperatures are discussed.
Researches on the alkoxy‐amino‐nitrobenzenes: IV). Nitration of 1‐alkoxy‐2‐arylsulphonylaminobenzenes
Authors: Bosma G. S. K. , Meerburg W. , Verkade P. E. 
Published: September 2010

AbstractThe nitration of some 1‐alkyloxy‐2‐p‐toluenesulphonylaminobenzenes under different conditions is described. The results are discussed from a theoretical standpoint.
Études dans la Série du Thiophène: I. Cétones dérivées du 2,5‐diméthylthiophène (2,5‐thioxène) et certaines de leurs réactions
Authors: Buu‐Hoï Ng. Ph. , Nguyen‐Hoán  
Published: September 2010

AbstractDans ce travail, on décrit la synthèse et les propriétés d'une série de cétones dérivées du 2,5‐thioxène (2,5‐diméthylthiophène). Certaines des cétones aromatiques ainsi obtenues subissent aisément la réaction d'Elbs, et conduisent à des substances polycycliques appartenant au noyau du thiophanthrène; ces corps sont des isostères d'hydrocarbures du groupe de l'anthracène et du 1,2‐benzanthracène. Une nouvelle méthode de préparation commode est indiquée pour l'acide 2,5‐diméthyl‐3‐thenoïque, et plusieurs dérivés de ce corps sont décrits, ainsi que certains aryléthylènes dérivant du 2,5‐thioxène. L'étude de la réaction de Pfitzinger montre enfin que le noyau 2,5‐thioxène produit un empêchement stérique.
Energetic data on the carbon ‐ carbon bond IV. Energy of activation, arrhenius constant and period of half‐life for the radical‐dissociation reaction of six hydrocarbons of the pentaphenylethane type in o‐dichlorobenzene as a solvent
Authors: Coops J. , Galenkamp H. , Haantjes J. , Luirink H. L. , Nauta W. Th. 
Published: September 2010

AbstractThe energy of activation (E), the Arrhenius constant (A) and the period of half‐life at 80° (t1/2) for the radical‐dissociation reactions of the following compounds:pentaphenylethane (I)1,1,1,2‐tetraphenyl‐2‐(2‐methylphenyl)ethane (II)1,1,1,2‐tetraphenyl‐2‐(3‐methylphenyl)ethane (III)1,1,1,2‐tetraphenyl‐2‐(4‐methylphenyl)ethane (IV)1,1,1‐triphenyl‐2,2‐di‐(3‐methylphenyl)ethane (V)1,1,1‐triphenyl‐2,2‐di‐(4‐methylphenyl)ethane ((VI)have been calculated from the velocity constants for the first‐order reactions of the radicals concerned with oxygen in o‐dichlorobenzene as a solvent:magnified image
Kinetics of gas‐liquid reactions part I. General theory
Authors: van Krevelen D. W. , Hoftijzer P. J. 
Published: September 2010

AbstractWhen a gaseous component is absorbed by a liquid under simultaneous reaction with a component of the liquid, the overall rate of reaction proves to be a dimensionless function of four limiting rates:
the maximum rate of diffusion of the gaseous component through the liquid film
the maximum rate of diffusion of the liquid‐component through the liquid film
the limiting rate of reaction within the liquid film (during diffusion)
the maximum rate of reaction within the main body of the liquid.
A graphical representation of the theoretical relationship enables one to predict the overall rates of interphase mass exchange under arbitrary conditions, as soon as reaction velocity coefficients and mass transfer coefficients are available.
Permanganometrische Untersuchungen III: Die Bestimmung der Azide und der Stickstoffwasserstoffsäure mit Kaliumpermanganat
Authors: van der Meulen J. H. 
Published: September 2010

AbstractMéthode d'analyse volumétrique de l'acide azothydrique et des azotures au moyen de permanganate de potassium, préalablement réduit par un sel de manganèse bivalent en excès, en présence d'acide sulfurique et d'acide phosphorique.L'excès de permanganate est dosé avec d'iodure de potassium par titrage de l'iode libéré au moyen de thiosulfate de sodium décinormal.
Etude sur les Oxydes de Thiouree. IV
Authors: Böeseken J. 
Published: September 2010

AbstractLa propriété fortement réductrice d'une solution ammoniacale du dioxyde de thiourée ne peut pas être attribuée à la formation passagère du sel d'ammonium de l'acide sulfoxylique, car les éthers éthyliques de cet acide, en solution alcaline, ne précipitent pas les sels de cadmium à l'état de cadmium métallique. Le dioxyde lui‐même doit être la cause de cette propriété remarquable.Cependant, la décomposition en solution ammoniacale:

est prouvée par la présence, après quelque temps, des ions S2O3, SO4, SO3 et S. Le Ni et le Cd précipités contiennent toujours des quantités assez considérables de S et d'oxygène.Le fait que le cadmium et tous les éléments plus électronégatifs provoquent un dégagement lent d'hydrogène peut être déduit de la place de l'hydrogène dans la série des forces électromotrices des éléments.En solution ammoniacale, le dioxyde s'empare d'un atome d'oxygène: en présence des sels de Ni, Fe, Co, etc., deux atomes d'oxygène sont fixés; le soufre est alors transformé en sulfate. Cette réaction, partiellement catalytique, a étè étudiée de plus près.La méthylthiourée donne avec H2O2 l'acide méthylformamidine‐sulfinique, qui montre les mêmes réactions que l'acide formamidine‐sulfinique lui‐même; en solution aqueuse et légèrement acide, il est un peu plus stable.Enfin, nous avons étudié l'oxydation de la benzylisothiourée par H2O2, dans l'espoir d'obtenir l'éther benzylique de l'acide formamidine‐sulfinique, mais en vain.En oxydant la benzylisothiourée par l'acide peracétique, nous avons obtenu une substance C23H17S3N3O5; dont nous avons établi la structure avec quelque probabilité.
A general method for quantitative spectrochemical analysis: (Preliminary communication)
Authors: Addink N. W. H. 
Published: September 2010

AbstractTill now Gerlach's internal standard method has been applied to all kinds of quantitative spectrochemical analysis. According to this method it is necessary to prepare for each individual material to be analysed series of samples in order to set up working curves, relating concentration and intensity ratio of lines of the element sought for and the standard‐element.Harvey (1947) uses the background near a line of the element as a kind of internal standard and his book contains many useful data for two‐component systems.However, materials containing many major constituents as mixtures of salts, oxides or metals themselves cannot be analysed with great accuracy according to Harvey's method.In the following paper a general method derived from Harvey's is described; it can be divided into two parts; one for the rough estimation of the element concentration and a second part for the exact determination, obtained by successive additions of the element sought for. If the straight portion of the characteristic curve of the photographic emulsion is used, a simple evaluation of the concentration is given whereas the knowledge of the accurate shape of the characteristic curve is not essential.
Ultraviolet absorption spectra and stereochemical structure of plant growth substances of the cis cinnamic acid type and of stilboestrol
Authors: Havinga E. , Nivard R. J. F. 
Published: September 2010

AbstractUltraviolet absorption spectra are recorded of cis‐ and trans‐ cinnamic acid, of cis‐ and trans‐1,2,3,4,‐tetrahydronaphthylidene (1) acetic acid and of cis‐ and trans‐β‐(naphthyl‐1) acrylic acid. The cis isomers all show a lower extinction coefficient and a shift of the maximum of absorption to shorter wave‐length in comparison with the trans isomers. It is concluded that as a result of steric hindrance in the case of the cis compounds the conjugation between aromatic ring system and carboxyl group is hindered, the molecules not possessing a plane structure. The fact that all these cis compounds show marked activity as plant growth promoter, whilst the trans isomers are totally inactive, is in accordance with the conclusions about their stereochemical structure. Comparison of the ultraviolet absorption spectra of stilboestrol and of p,p′‐dihydroxystilbene leads to the conclusion that the stilboestrol molecule does not have a plane structure and that it is doubtful whether the explanation of the oestrogenic activity based on its often suggested „formal”︁ similarity to the natural oestrogenic hormones is justified.
Bromo‐derivatives of 3,5‐diethoxypyridine
Authors: den Hertog H. J. , Mulder B. 
Published: September 2010

AbstractTwo dibromo‐diethoxypyridines of undetermined structure are described in the literature, viz. a compound melting at 142° bySelland an isomer with m.p. 165°, byKönigs, GerdesandSirot.We have shown that the bromine atoms occupy the 2 and 6 positions in the bromo‐derivative melting at 142°. The compound melting at 165°, prepared according to the directions ofKönigsand his co‐workers, appears to be 2‐bromo‐3,5‐diethoxy‐6‐nitro‐pyridine instead of a dibromo‐diethoxypyridine.2,6‐Dibromo‐3,5‐diethoxypyridine was isolated bySellas the sole reaction product from the bromination of 3,5‐diethoxypyridine in an acid medium. By carrying out the bromination in pyridine as solvent, we have obtained 2‐bromo‐3,5‐diethoxypyridine along with the dibromo‐compound. The further bromination of this mono‐bromo‐compound is a reversible process; the dibromo‐derivative is converted into mono‐bromo‐diethoxypyridine by heating with a solution of hydrobromic acid in glacial acetic acid.Finally we have examined the action of cuprous cyanide, sodium ethylate and nitric acid on the 2‐bromo‐ and the 2,6‐dibromo‐derivative of 3,5‐diethoxypyridine.In proving the structure of derivatives of 3,5‐diethoxypyridine, the possibility of the occurrence of various abnormal substitution reactions with these substances must be taken into account.
The carbohydrates in grass. I. The soluble carbohydrates
Authors: de Man Th. J. , de Heus J. G. 
Published: September 2010

AbstractA method is worked out according to which a separate determination of aldoses, fructose, sucrose and fructosan in grass is possible.The contents of these substances in relation to the age of the grass are determined; the fructosan content passed through a peak.Evidence was obtained that the sucrose content was highest on bright sunny days.Sucrose appeared to be the only carbohydrate which showed a distinct diurnal variation.
The heat of mixing in the system n‐heptane‐n‐hexadecane: Preliminary communication)
Authors: van der Waals J. H. , Hermans J. J. 
Published: September 2010

AbstractThe heat of mixing in the system n‐heptane‐n‐hexadecane is measured. When this heat of mixing is subtracted from the excess free energy determined by Brønsted and Koefoed an excess entropy is obtained which is in good agreement with the theoretical formula developed by Guggenheim.
Oxidative phenomena in dilute solutions of substances with a system of conjugated double bonds. I. Vitamin‐A Acetate
Authors: Groot E. H. 
Published: September 2010

AbstractIn measuring absorption spectra of substances containing a system of conjugated double bonds, in very dilute solutions with the aid of a Beckman spectrophotometer, typical abnormalities in the spectra are sometimes found which in all probability have their origin in autoxidative phenomena of the substance in solution.
Syntheses of polychloro compounds with aluminium chloride VII: The auto‐condensation of 1,2,3,3‐tetrachloropropene‐1
Authors: Prins H. J. 
Published: September 2010

AbstractThe synthesis of polychloro compounds by the catalytic action of aluminium chloride has been extended to the auto‐condensation of 1,2,3,3‐tetrachloropropene‐1 giving 1,2,3,4,5,5,6,6‐octochlorohexene‐1.This octochlorohexene gives hexachlorohexadienes when treated with alcoholic potash solution.
Absorption spectra of quinones. I. Naphthoquinones and naphthohydroquinones
Authors: Spruit C. J. P. 
Published: September 2010

AbstractThis paper reports the ultraviolet and visible absorption spectra of a number of derivatives of 1,4‐naphthoquinone and 1,4‐naphthohydroquinone. A statistical analysis of the spectra shows that the absorption bands of the quinones may be divided into three groups. Two of these groups contain absorption bands, the position of which is only slightly dependent upon the nature of the substituents, and which are characteristic of the class of the naphthoquinones. The bands of the third group, situated mainly in the visible and near ultraviolet, are determined by the structure of the molecule as a whole. It is shown by several examples that the wavelengths of bands from the last group increase when negative charge is introduced into the nucleus by the attachment of substituents able to donate electrons, such as hydroxy groups. The reverse holds for electron‐attracting groups such as the carbonyl group.