bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Preparation of 1‐Alkoxy‐2‐Amino‐4‐Nitrobenzenes in Aqueous Solution
Authors: Blanksma J. J. 
Published: September 2010

Abstract1‐Alkoxy‐2‐amino‐4‐nitrobenzenes are prepared by reduction of 1‐alkoxy‐2:4‐dinitro‐benzenes with sodium disulphide in aqueous solution instead of in the appropriate alcohols with a corresponding economy in the use of the latter.J. J. Blanksma and P. W. M. van der Weyden, This Journal 59, 629 (1940).
This can be accomplished without difficulty because the alkoxy group in the 1‐alkoxy‐2‐amino‐4‐nitrobenzenes is so slightly reactive that it is not replaced by hydroxyl during the reduction.
Über Die Synthese von Epi‐g‐glutathion: 10. Mitteilung über die Chemie der Tumoren
Authors: Kögl F. , Akkerman A. M. 
Published: September 2010

AbstractIn der Arbeit wird die Synthese eines stereoisomeren Glutathions beschrieben, das im Gegensatz zum gewöhnlichen Tripeptid den d‐Glutaminsäure‐Baustein enthält. Die Eigenschaften von Epi‐g‐glutathion (γ‐d‐Glutamyl‐1‐cysteinyl‐glycin) sind in Zusammenhang mit den Untersuchungen über die Konfiguration der Bausteine von Tumorproteinen von Interesse.
The adsorption of carbon disulphide vapour and water vapour by active charcoal
Authors: Vreedenberg H. A. , van Nouhuys H. L. 
Published: September 2010

AbstractThe adsorption isotherms of CS2 and of H2O by Norit charcoal were determined. In addition the adsorption from mixtures of the two vapours was investigated. Some measurements were carried out about the rate at which the equilibrium of adsorption is reached; in the case of adsorption from a mixture it was found that CS2 is at first adsorbed, but that afterwards H2O is substituted for the adsorbed CS2. All experimental results are described by means of a theory differing from the Langmuir theory by the assumption that the number of adsorbed molecules passing into the vapour phase per unit of time depends on the vapour pressure.
Synthèse de Nouveaux Acides Gras α, α‐Disubstitués
Authors: Buu‐Hoï N. G. Ph. , Cagniant Paul 
Published: September 2010

AbstractPoursuivant leurs recherches sur la chimie des acides gras α, α‐disubstitués les auteurs décrivent dans le présent travail une série de représentants nouveaux de cette famille de substances. II est montré en outre que les amides des acides gras α, α‐diméthylés ne peuvent être saponifiés par la potasse alcoolique que lorsqu'ils renferment une double liaison dans leur molécule.
The purification of carbon rods for spectrochemical analysis: I. A simple apparatus for purification by means of resistance heating
Authors: Hoogland P. L. 
Published: September 2010

AbstractA method is described for the purification of carbon electrodes for the purpose of obtaining material which can be used as supporting electrode in spectrochemical analysis of biological material according to the cathode‐layer method.The principle of the method is that of raising the carbon rods to a very high temperature by resistance heating as employed by Gatterer.Starting with “Siemens‐Plania Superbio Negativ Kohle” a useable product was obtained.The heating process took place in such a way that several quantitative considerations could be related to it.
The purification of carbon rods for spectrochemical analysis: II. Carbon rods for spectrochemical analysis of solutions
Authors: Schmidt R. 
Published: September 2010

AbstractThe Scheibe‐Rivas method of spectrochemical analysis of solutions makes use of carbon rods which are impregnated with the solution to be analysed. The carbon rods must be pure, homogeneous and porous. The preparation of pure carbon rods fulfilling these requirements is described.
The sweet taste of 4‐nitro‐2‐aminotoluene, 4‐nitro‐2‐aminobenzoic acid and 2‐nitro‐4‐aminobenzoic acid
Authors: Blanksma J. J. , Hoegen D. 
Published: September 2010

Abstract4‐Nitro‐2‐aminotoluene is 330 times as sweet as sugar. 2‐Nitro‐4‐aminotoluene is tasteless, 4‐nitro‐2‐aminobenzoic acid is 25 times, and 2‐nitro‐4‐aminobenzoic acid 120 times, as sweet as sugar. The acetyl derivatives of these compounds, as well as the esters of the acids and their acetyl derivatives, are all tasteless.
The bromination of 2‐aminopyridine in the gas phase at 500°
Authors: den Hertog H. J. , Bruin P. 
Published: September 2010

AbstractWhen 2‐aminopyridine and bromine in the form of vapour diluted with nitrogen are passed over pumice at 500°, a violent reaction takes place, much carbon is deposited and a complex mixture of brominated aminopyridines is formed.3 isomeric monobromo‐compounds could be isolated from the mixture, i.e. 2‐amino‐3‐bromopyridine, 2‐amino‐5‐bromopyridine and 2‐amino‐6‐bromopyridine. It contained further 3 dibromo‐compounds (2‐amino‐3,5‐dibromopyridine, 2‐amino‐3,6‐dibromo‐pyridine and 2‐amino‐5,6‐dibromopyridine) and one tribromo‐compound (2‐amino‐3,5,6‐tribromopyridine).The reaction described differs considerably from the bromination of 2‐amino‐pyridine at room temperature, by the last process a mixture of only 2‐amino‐5‐bromo‐pyridine and 2‐amino‐3,5‐dibromopyridine being formed.
Vaccenic acid in butterfat and the fluctuations in its amount
Authors: Brouwer E. , Jonker‐Scheffener M. C. E. 
Published: September 2010

AbstractButterfat contains a notable quantity of vaccenic acid when the cows are on grass. On two winter rations the contents were only small. In butterfat from evening milk and from morning milk the contents are about the same.There exists a positive correlation between the vaccenic acid content and the iodine value of butterfat. However, the iodine value being the same, the vaccenic acid contents on the winter rations were distinctly lower than on grass.
Quantitative evaluation of orientation in cellulose fibres from the X‐ray fibre diagram
Authors: Hermans J. J. , Hermans P. H. , Vermaas D. , Weidinger A. 
Published: September 2010

AbstractThe theory of fibre diagrams as given by Polanyi and first applied to cellulose fibres by Sisson and Kratky enables one to derive the orientation in a fibre from the intensity distribution in the diatropic interferences. Since these interferences are usually too weak in the X‐ray diagrams of cellulose fibres, we must resort to the paratropic reflexions. The present paper shows how these paratropic reflexions must be evaluated to obtain the orientation factor fr as a rational measure of average orientation. It is shown on experimental grounds that the proximity of the A4 interference does not invalidate the evaluation of the A3 sickle. A special procedure must be applied to fibres in which the orientation is not very pronounced, since here the interferences of the (021) planes partly overlap those of the paratropic A3 planes.It is assumed throughout this article that in all experiments the Bragg angle is negligible. The correction required when dealing with finite Bragg angles is discussed in section 6.The relation between orientation and optical constants is set forth in section 5. Finally, section 8 gives an illustration along with a short summary of the method.
Des Quinoléines Substituées. V: Polyalkyl‐Quinoléines et Polyalkyl‐Naphtoquinoléines
Authors: Buu‐Hoï Ng. Ph. , Guettier Daniel 
Published: September 2010

AbstractOn décrit la synthèse de plusieurs homologues polysubstituées de la quinoléine et des α‐ et β‐naphtoquinoléines, substances dont on désirait étudier certaines propriétés physiologiques. La méthode utilisée dans ces préparations est celle de Beyer‐Combes, méthode qui a également été appliquée à la synthèse de quelques amino‐quinoléines polysubstituées dont l'intensité de la fluorescence est tout à fait remarquable.
Equilibrium and stability
Authors: Bijvoet J. M. , Wiebenga E. H. 
Published: September 2010

AbstractAn isolated system in thermodynamical equilibrium is still in equilibrium after allowing for the possibility of interchange of heat or work between the system and properly adapted surroundings (i.e. for instance a bath at the temperature and pressure of the system). On the other hand the type of equilibrium ‐ stable, neutral or unstable ‐ can be changed by this contact.
Association in solutions of colloidal electrolytes; Hexanolamine elaidate and trihydroxy stearate
Authors: Gonick Emanuel , Mcbain James W. 
Published: September 2010

AbstractData for the electrical conductance and the lowering of freezing point of solutions of hexanolamine elaidate and of hexanolamine δ‐trihydroxy stearate are presented. It is shown that whereas the elaidate is a typical colloidal electrolyte, very highly associated into more or less conducting colloidal particles, the trihydroxy stearate, with soluble groups at both ends of the molecule, is an ordinary, fully dissociated electrolyte up to a concentration of at least 0.08 N.
On the diffusely diffracted radiation in the X‐ray diagrams of cellulose fibres
Authors: Hermans P. H. , Weidinger A. 
Published: September 2010

AbstractThis paper is concerned with the technique which can be used for the evaluation of the character of the X‐ray spectrum of the amorphous portion in cellulose from the general diffuse “background” scattering. It is shown that this spectrum consists of a very broad band with a flat maximum between the 101 and the 101 interference (fig. 3), corresponding to a spacing of 5‐6 Å.
A combined micro‐gravimetric and titrimetric micro‐determination of thallium in toxicological material
Authors: Reith J. F. , Gerritsma K. W. 
Published: September 2010

AbstractA method is described for the specific determination of from 0.01 to 5 mg of thallium in excreta and organs. It is based upon the partial destructive oxidation with potassium chlorate and hydrochloric acid, extraction with ether as TlCl3, removal from the ether layer as TlCl with water containing SO2 and destruction of minute quantities of accompanying organic substances. The thallium is precipitated as TlI and isolated by centrifuging. The precipitate can be determined micro‐gravimetrically, however, with < 0.1 mg of thallium the error in weighing is relatively large.The iodometric titration of the TlI here first described is always more accurate. The principles of sources of error of the operations are discussed. The ions Pb, Hg, Cu, As, Sb, Bi and Fe do not interfere.
The difference in reactivity of aromatic bonds
Authors: Kooyman E. C. , Ketelaar J. A. A. 
Published: September 2010

AbstractA hypothesis) Compare E. C. Kooyman, Thesis, Amsterdam 1946, § 3.
) is given concerning the mechanism of some reactions of aromatic compounds, which tries to reconcile the fact that, as a result of resonance, no double bonds are present in these molecules, and the conclusion following from organic chemical experiments, that in some aromatic molecules fixed double bonds seem to occur.The hypothesis offers among other things an explanation for the striking difference between the 1,2‐ and 2,3–bonds in naphthalene.
Studies of gas absorption: II. Application of the liquid film resistance relationship to the absorption of carbon dioxide by solutions of diethanolamine
Authors: van Krevelen D. W. , Hoftijzer P. J. 
Published: September 2010

AbstractThe general equation for liquid film resistance to gas absorption in scrubbers, derived by us in a previous paper 1), was applied to experiments of Cryder and Maloney2), treating the absorption of carbon dioxide in diethanolamine solutions. Our equation proved to be valid also in this case, when it is assumed that the reaction is a pseudo‐third order reaction. In reality it will be a succession of two second order reactions, as no temperature influence on the reaction velocity constant is found.
Chemical constituents of mundulea suberosa benth. Part I
Authors: Meijer Th. M. 
Published: September 2010

AbstractA review is given of the literature on the occurrence and application of Mundulea suberosa. Chemical investigation of the bark of the branches led to the isolation of rotenone, a white substance C23H20O7, m.p. 193‐195° C, and from the root bark a yellow substance C23H20O7, m.p. 216‐220° C was isolated. Both products contained two methoxyl groups. Treatment of the colourless crystals with glacial acetic acid and sulphuric acid furnished a yellow product of the composition C23H18O6. Oxidation with chromic acid gave a substance C23H18O7, m.p. 262°C. A comparison was made with known rotenoid substance of similar composition.
Preparation of hydrogen peroxide from the peroxides formed on oxidizing propane
Authors: Kooijman P. L. 
Published: September 2010

AbstractAn investigation is described of the conversion of the peroxide solution, obtained on oxidizing propane, into hydrogen peroxide. The method of doing this is based on the conversion of the said peroxide solution into calcium or barium peroxide by means of calcium or barium hydroxide, which process gives a high yield. Following this conversion, the calcium or barium peroxide is transferred into a dilute hydrogen peroxide solution by means of carbon dioxide, whereas the carbonate is precipitated and filtered off. This conversion, too, proceeds with a high yield.
The colorimetric evaluation of Derris root
Authors: Meijer Th. M. , Rachmad A. 
Published: September 2010

AbstractA more precise procedure for the colorimetric evaluation of Derris root is described, making use of the colour which rotenone and the matter which may be extracted from Derris root by ether produce with concentrated sulphuric acid containing a trace of sodium nitrite. Rotenone is used as a standard. A number of samples of Derris powder with varying contents of rotenone and ether extract were analyzed. It was found that the amount of “rotenoid” substances present in the different samples corresponded fairly well to the ether extract.
Preparation and some physical constants of 2‐methyltetradecane and 3‐methylpentadecane
Authors: Lunshof H. J. , van Steenis J. , Waterman H. I. 
Published: September 2010

AbstractSince the authors were interested in the physical constants of some branched chain hydrocarbons in connection with other work, 2‐methyltetradecane and 3‐methylpentadecane were prepared and some of their physical constants determined.
On metastable eutectics in binary salt systems
Authors: Korvezee A. E. , Dingemans P. , Dijkgraaf L. L. 
Published: September 2010

AbstractThe eutectic in any given binary system cannot be derived from the melting point and heat of fusion of the components. Formulae based upon an ideal form of the melting‐point curves cannot of course give more than a rough approximation.When one of the components in a binary system occurs in two crystalline modifications, a metastable eutectic occurs in addition to the stable eutectic. If the transition point lies close to this metastable eutectic, simple formulae, based upon ideal behaviour, can be derived for the distance between the two eutectics.With the small differences in question these formulae are found to be useful for salt melts. The values found give reasonable agreement with those which are obtained by extrapolation of relative vapour‐pressure curves.
The preparation of peroxides by the oxidation of ethane
Authors: Kooijman P. L. 
Published: September 2010

AbstractA description is given of an investigation into the optimum conditions for preparation of the peroxides which are formed when ethane is incompletely oxidized with oxygen. It has appeared that under optimum reaction conditions the ethane is only reactive in a high temperature range. On adding a small quantity of acetaldehyde, however, it also reacts at low temperature producing peroxides. The addition of 0.1% by vol. of acetaldehyde vapour to the ethane‐oxygen mixture proved to be a means of raising the hydrogen‐peroxide yield from 0.4 mol. % to 0.7 mol. % of the ethane feed.
Vapour‐liquid equilibria in ternary systems. V. The system water‐formic acid‐metaxylene
Authors: Reinders W. , de Minjer C. H. 
Published: September 2010

AbstractThe equilibria between liquid and vapour in the system water‐formic acid‐metaxylene have been investigated. The system has a saddle point in the region of partial miscibility, which is situated for a pressure of 760 mm at a temperature of 97.5° and at a vapour composition of 10.6% water, 40.4% formic acid and 49.0% m‐xylene.From these equilibria was deduced how one can use m‐xylene for dehydrating the azeotropic water‐formic acid mixture with 22.6% water and with what yield.
Gradual separation and economy: 5th Communication, separation by distillation
Authors: Treub J. P. 
Published: September 2010

AbstractIn this communication the requirements a distillation column has to meet will be dealt with and the way, wherein a theoretically correct column may be built up and has to be economically manipulated, will be shown. In such a column, which has an “uphold”, that is negligible, relations may be applied for practical purposes, which hold for theoretical plates, so that in many cases a simple mathematical analysis of the process of distillation is possible.
Quantity of adsorbent and temperature as factors in adsorption from solution
Authors: Groves T. E. , Bowden S. T. , Jones W. J. 
Published: September 2010

AbstractThe effect of variation of mass of adsorbent and of temperature on the adsorption of acetic acid from dilute aqueous solution by charcoal has been measured. It has been found, first, in agreement with Burgers but contrary to Wo. Ostwald, that for each temperature the amount of solute adsorbed per unit mass of adsorbent is a uniform function of the final concentration of the solution, independent of the quantity of adsorbent used per unit volume of the solution, and secondly, in disagreement with some of the results published by Freundlich, that for a given value of the final concentration the amount adsorbed per unit mass of adsorbent falls consistently as the temperature is raised.
A cis‐C18‐ketone, related to vitamin A
Authors: Arens J. F. , van Dorp D. A. 
Published: September 2010

AbstractA by‐product of the Reformatzky‐reaction of β‐ionone and ethyl γ‐bromocrotonate is a cis‐β‐ionylidene‐crotonic acid I. This acid can easily be converted into the cis‐C18‐ketone by means of lithiummethyl.
Über 4(7)‐amino‐benzimidazol: 2. Mitteilung über des‐aza‐purin‐derivate
Authors: van der Want G. M. 
Published: September 2010

AbstractIn der vorliegenden Arbeit wird gezeigt, dass die in der Literatur als 4(7)‐Amino‐benzimidazol beschriebene Verbindung in Wirklichkeit die Aminogruppe an Stelle 5 (bzw. 6) trägt. Das bisher unbekannte 4(7)‐Aminobenzimidazol ‐ dem wegen seiner strukturellen Beziehung zu Adenin ein gewisses Interesse zukommt ‐ wurde dargestellt und mit der isomeren Verbindung verglichen.
The calcium salts obtained by the complete extraction of coca leaves and the determination of the acid esters of l‐nor‐ecgonine
Authors: de Jong A. W. K. 
Published: September 2010

AbstractThe calcium salts contain besides the acid esters of l‐nor‐ecgonine, calcium salts of ordinary acids, one or more esters of ordinary acids and an amide.The quantity of the acid ester of l‐nor‐ecgonine is determined in the following way. The calcium salts are acidified with a few drops of strong HCl solution and the acids and the esters of ordinary acids extracted by ether. The neutralized HCl solution basified with a known quantity of n/10 NaOH solution and boiled in a Kjehldal apparatus as used for ammonia determinations. The quantity of acid esters is equivalent to the loss of NaOH diminished by the quantity of ammonia obtained.
The vapour pressure of saturated solutions of sodium nitrate in water
Authors: Dingemans P. , Dijkgraaf L. L. 
Published: September 2010

AbstractThe vapour pressure of saturated solutions of NaNO3 in water was measured from 10° C to 150° C.From these measurements it is found that the relative vapour pressure p/pw plotted as a function of the temperature gives a slightly curved line, as previously obtained for some other saturated salt solutionsMiss A. E. Korvezee and P. Dingemans, Rec. trav. chim. 62, 625 (1943).
).
Investigations on sterols II): Vitamin‐D2 and ‐D3 in irradiated sterol from the mussel (mytilus edulis))
Authors: van der Vliet J. 
Published: September 2010

AbstractThe following compounds have been detected in the sterol fraction from the mussel (mytilus edulis) after irradiation with ultra‐violet light: Vitamin‐D2 and ‐D3 and a compound closely related to ‐D2 and having a vitamin‐D structure, but which is practically devoid of anti‐rachitic action. A mixture of this compound with vitamin‐D2 has been isolated in a crystalline state (‐Dx).
Decomposition of o‐hydroxydiazonium compounds by light
Authors: de Jonge J. , Dijkstra R. 
Published: September 2010

AbstractConditions could be found for decomposing a solution of an o‐hydroxybenzene diazonium compound into a colourless product.Such an irradiation product couples with diazonium salts in slightly acidic solution to red‐shaded dyes according to a bimolecular reaction.However, it is not stable in solution at room temperature, but is converted slowly into a non‐coupling dimeric form.The irradiation of the diazonium salt gives rise to a new, weak acid function, that disappears again on heating, with evolution of CO2.Titration curves show that the o‐hydroxybenzene‐ and o‐hydroxynaphthalene‐diazonium compounds are decomposed in a similar way.Two irradiation products of o‐hydroxynaphthalene‐diazonium compounds have been isolated.Our results are completely understood by assuming the conversion of the benzene‐nucleus into a five‐membered ring, as recently concluded by Süs from other experiments.
The chemistry of 2‐aminofluorene: 2. Reaction with dihydroxymalonic ester
Authors: Neish W. J. P. 
Published: September 2010

Abstract2‐Aminofluorene reacts with dihydroxymalonic ester yielding ethyl fluorene dioxindole carboxylate, which is readily hydrolysed and oxidised to an isatin derivative, 2′,3′‐indeno‐4,5‐isatin. The latter compound yields an oxime.
Titration of adsorbed acids
Authors: Tendeloo H. J. C. , Mans A. E. , de Hoogh G. 
Published: September 2010

AbstractThe researches here described deal with electrometric titrations of strong acids in the presence of adsorption charcoal (Norit). The titration curves of the system containing charcoal are of the type of titration curves of weak acids; the systems have a pronounced buffer capacity.
Steric effects on mesomerism: I. General considerations on the deacylation of aromatic acylaminocompounds with a nitro group in the ortho‐ or para‐position
Authors: Wepster B. M. , Verkade P. E. 
Published: September 2010

AbstractThis paper is the first of a series dealing with an investigation of the rates of deacylation of aromatic acylamino compounds having a nitro group in ortho‐ or para‐position, with the aim of obtaining further (semi‐) quantitative information with regard to “steric effects on mesomerism” (“steric hindrance of resonance”).In the first section some remarks on the nomenclature have been made, more in particular on the use of the “neutral” word “effect”, rather than the more customary “hindrance”. Further, it has been pointed out that the so‐called “Mills‐Nixon effect” should be regarded as a special case of steric effects on mesomerism, viz. as a steric effect on mesomerism due to changes in valency angles.The mechanism of the deacylation has been discussed in some detail; the mesomerism in the ortho‐ or para‐nitrophenylamino grouping is regarded to be mainly responsible for the “catalytic” deacylation.The question as to whether the slow deacylation observed in some cases might be caused by steric hindrance in the classical sense, rather than by steric effects on mesomerism, has been considered, the conclusion being that steric hindrance is certainly not of prime importance.In the last section the method by which the rates of deacylation are compared in order to get an insight into the magnitudes of the steric effects on the mesomerism, has been given and discussed briefly.