bluuebunny/crossref_metadata_2025_split huggingface dataset:
The behaviour of membranes between electrolyte solutions. II. Membrane potentials at oxidized cellophane
Authors: Hirsch P. 
Published: September 2010

AbstractIn order to test the inference arrived at in Part I that the membrane potential at cellulose membranes depends on the dissociation of acid groups in the membrane substance, experiments were carried out with cellophane membranes, in the cellulose of which carboxyl groups had been produced by oxidation. The membrane potential thus raised and that at the original cellophane depend on the pH in a like manner. This is apparent from the shape and position of the Δ.pH‐curves. In this case Δ is no longer the same for KCl and NaCl.
L'action D'hydrazine sur Quelques Sulfonyl‐Cétones; Réduction Selon Wolff Kishner Sans Catalyseur. (Propriétés du groupe sulfonyle XXIV)
Authors: Kloosterziel H. , Backer H. J. 
Published: September 2010

AbstractL'observation que le groupe carbonyle de la “sulfobenzophénone” (I) est réduit par chauffage avec l'hydrazine nous a amenés à étudier le comportement de quelques autres sulfonylcétones, spécialement de celles où le groupe sulfonyle, soit par proximité soit par vinylogie, peut influer sur le groupe carbonyle.Le thionaphténone‐3‐1‐dioxyde (III) et la p‐méthylsulfonylacétophénone (V) sont réduits par l'intermédiaire de leurs hydrazones. La p‐tolylsulfonylacétone (XI) donne une hydrazone qui n'est pas réduite par chauffage avec l'hydrazine.Les sulfonylcetones suivantes sont scindées:p‐méthylsulfonyl‐α‐(p‐tolylsulfonyl)‐acétophénone (VII)β‐(p‐tolylsulfonyl)‐acrylophénone (X)benzylsulfonyl‐acétone (XII).Enfin l'hydrazone de la 1,3‐bis‐p‐tolylsulfonyl‐acétone (XIII) montre un comportement remarquable que l'on peut expliquer en admettant qu'il se forme, par “hydrazinolyse”, une hydrazide‐hydrazone qui subit la scission de la réaction Wolff Kishner.
Sodium salts of pectin and of carboxy methyl cellulose in aqueous sodium chloride. I. Viscosities
Authors: Pals D. T. F. , Hermans J. J. 
Published: September 2010

AbstractThe extrapolation of the ηsp/c versus c curves for polyelectrolytes in dilute salt solutions is difficult because these curves show a sharp maximum at a polymer concentration, c, where the equivalent concentration of the polyelectrolyte is of the same order of magnitude as that of the extraneous salt. A more reliable figure for the intrinsic viscosity can be obtained if the effective ionic strength is kept constant or nearly constant, in which case ηsp/c versus c becomes a straight line. The slope of this line is discussed in § 8.The intrinsic viscosities discussed are those of a pectinate and three samples of sodium carboxy methyl cellulose (Na—CMC) in aqueous solutions of sodium chloride. The experimental results can be described satisfactorily by the theory of Hermans and Overbeek. The only unknown parameter is the average square of the distance between the ends of the uncharged molecule, and its value compares well with that known for other cellulose derivatives.At the limit of zero ionic strength the molecules are practically fully stretched. The application of Simha's formula for ellipsoidal particles leads to reasonable values for the molecular length.In connection with the high precision aimed at, a study was made of the effect of surface tension in viscometry. This is described in § 4, and leads to the conclusion that for our purpose an Ubbelohde viscometer has preference above an Ostwald viscometer. It was found, further, that the intrinsic viscosity of the polyelectrolytes investigated is a function of the shear‐rate. This phenomenon will be more fully discussed elsewhere.
An improved method for the determination of 2,4 d acid (2,4‐dichlorophenoxy acetic acid) and of M.C.P.A. (2‐methyl‐4‐chlorophenoxy acetic acid) in herbicidal formulations
Authors: Ketelaar J. A. A. , Gersmann H. R. 
Published: September 2010

AbstractA revised method is given for the determination of 2,4 D acid (2,4‐dichlorophenoxy acetic acid) and M.C.P.A. (2‐methyl‐4‐chlorophenoxy acetic acid) in herbicidal formulations (total phenoxy acetic acids). The preliminary removal of free phenols and cresols is not necessary if methyl red and phenol red respectively are chosen as indicators.The dissociation constants were determined of some chlorophenols and ‐cresols of the corresponding phenoxy acetic acids (table I).
Cryoscopic and spectroscopic studies of mixtures of HNO3 and BF3
Authors: Gerding H. , Heertjes P. M. , Revallier L. J. , Steeman J. W. M. 
Published: September 2010

AbstractA cryoscopic study of mixtures of HNO3 and BF3 reveals the existence of a compound HNO3. 2BF3 (melting point 53° C). Mixtures of composition HNO3. 1/2BF3, HNO3. BF3, HNO3. 2BF3 and HNO3. 1/2SO3 were studied spectroscopically. In liquid HNO3. 1/2BF3 and HNO3. BF3 the reaction HNO3 + BF3 → NO+2 + BF3OH‐ takes place to a more or less considerable extent. In HNO3. 2BF3 no clear indication for the presence of NO2+ ions is found. HNO3. 2BF3 probably is an addition compound comparable with those described by Baumgarten c.s. for BF3 with a number of sulphates or pyrophosphates.In liquid HNO3. 1/2SO3 a considerable amount of NO2+ and HSO4 ions are present.
The reaction of urea with formaldehyde
Authors: de Jong J. I. , de Jonge J. 
Published: September 2010

AbstractThe reaction of urea and formaldehyde, giving monomethylolurea, is reversible in a neutral, acid or alkaline aqueous solution, the forward reaction being bimolecular and the reverse reaction monomolecular.The forward and reverse reactions are catalyzed to the same extent by hydrogen ions as well as by hydroxyl ions. The specific rates are directly proportional to the hydrogen and hydroxyl ion concentrations. There appears to be an influence of the buffer concentration on the reaction rates probably due to a general acid and general base catalysis.The equilibrium is almost independent of the pH of the solution and of the buffer concentrations.The activation energies of the forward and the reverse reaction have been determined, giving the heat of reaction. Within experimental error these activation energies may be the same for the non‐catalyzed and for the catalyzed system.The reaction mechanism is discussed.
Separation of small amounts of thorium from the cerite earths of monazite and other elements. Use of cinnamic acid
Authors: Krishnamurty K. V. S. , Venkateswarlu Ch. 
Published: September 2010

AbstractCinnamic acid has been found to be a suitable reagent for the estimation and separation of small amounts of thorium from the cerite earths of monazite. The latter in concentration upto 2000 fold may be conveniently separated in a single precipitation. Using this reagent a separation from other common elements may also be effected. The presence of a little nitric acid (about N/100) in the wash liquid is found useful in giving separations described particularly when dealing with relatively large amounts of the cerite earths.
Amides IX: Acylation of amides and amines
Authors: Dunn P. , Parkes E. A. , Polya J. B. 
Published: September 2010

AbstractFurther proofs are adduced in favour of the theory of add catalyzed acylation of amides to diacylamines. Synthetic examples are given partly as improvements of older methods, partly as illustrations of the theory. The preparation of the following new compounds is described: N‐isobutyrylbenzamide, N‐acetyl‐n‐butyramide, N‐methyldipropionimide and N‐methyldi‐n‐butyrimide.
On the heat of electrolytic dissociation of acetic acid and of the first h‐ion of citric acid in an aqueous solution
Authors: Snethlage H. C. S. 
Published: September 2010

AbstractThe heat of solution of citric and of acetic acid is calculated for various concentrations from the calorimetric experiments of Richards and his coworkers. From these data the heat of electrolytic dissociation of the two acids is calculated. By extrapolation, the heat effect at infinite dilution is evaluated. It is pointed out that for both acids the value of this last heat effect is in good agreement with the value which was obtained by Bates and Pinching for citric acid and by Harned and Ehlers for acetic acid from experiments on the change of the E.M.F. of suitable cells by temperature. Calculation of the heat of dilution from the heat of electrolytic dissociation at infinite dilution is possible at sufficiently low concentrations.
Contribution to the knowledge of metanethole III
Authors: van der Zanden J. M. , de Vries G. 
Published: September 2010

AbstractWe confirmed the structure of an oxidation product of metanethole with m.p. 180–180.5°, obtained by us on an earlier occasionI and II in Rec. trav. chim. 68, 261‐274 and 407‐418 (1949).
), by means of a synthesis.We synthesized metanethole in two different ways, and the stereoisomer, m.p. 99°, for which we had already found two methods of preparation, in a third way. In the light of the results obtained, we discussed the position of the H atoms in the 5‐membered ring of these products.For the metanethole oxidation product, m.p. 115–116°, we suggested a new structure as a possibility.
On the synthesis of ascorbic acids
Authors: Stedehouder P. L. 
Published: September 2010

AbstractThe preparation of ascorbic acids from derivatives of aldoses and esters of hydroxy‐alkoxy‐acetic acid, is describedDutch patent no. 59,711 of July 15th 1947. This investigation was carried out in 1942.
.l‐Ascorbic acid (Vitamin C) has been obtained from tetra‐acetyl‐l‐xylonic acid nitrile (tetra‐acetyl‐l‐threose‐cyanohydrin) and hydroxy‐ethoxy‐acetic acid ethyl ester. The latter compound is stable and easily accessible; a simplified method of preparation has been worked out for tetra‐acetyl‐l‐xylonic acid nitrile.d‐Ascorbic acid, l‐arabo‐acetic acid, and d‐gluco‐ascorbic acid have been prepared similarly.
The preparation of alkylthio substituted naphthoquinones‐1,4 and benzoquinones‐1,4
Authors: Tjepkema J. J. 
Published: September 2010

AbstractThe preparation of a number of 2,3‐dialkyl(aryl)thio‐naphthoquinones‐1,4 and 2,3,5,6‐tetraalkyl(aryl)thio‐naphthoquinones‐l,4 is described.
Polymerization of methylchavicol: Dimerization coupled with hydration II
Authors: van der Zanden J. M. , de Vries G. 
Published: September 2010

Abstractmagnified imageIn the preparation of II, just as in the earlier dimerization coupled with hydration of methylchavicol, , the two inactive stereoisomers were obtained. By reduction of the alcohol function they yielded, in accordance with the nature of the isomerism in question, the same final product.
Synthesis of potential chemotherapeutics in bile duct infections. I
Authors: van Kampen E. J. 
Published: September 2010

AbstractThe preparation of a chemotherapeutic for combating infections of the bile ducts is described.By coupling of 3′,3″‐diaminophenolphthalein withp‐acetylaminobenzene sulphochloride we obtained 3′,3″‐di‐acetylsulphanilylamidophenolphthalein, which by saponification was transformed into 3′,3″‐di‐sulphanilylamidophenolphthalein. This product was found, both by bacteriological and pharmacological investigation, to possess desirable chemotherapeutic properties.
A simple theory of electrophoresis: Determination of the equivalent weight of colloid electrolytes
Authors: de Wael J. , Wegelin E. 
Published: September 2010

AbstractA simple theory of electrophoresis has been given, starting from Kohlrausch's regulating function. Stress is laid on the correct method of calculating the mobility from the velocities of rising and descending boundaries. It appears to be possible to calculate the equivalent weight of colloid electrolytes from a Tiselius diagram
Synthesis of linear oligomers of ε‐amino. Caproic acid: Synthesis of a tri‐, tetra‐ and penta‐ω‐peptide
Authors: van der Want G. M. , Peters H. , Inklaar P. 
Published: September 2010

AbstractThe syntheses of three linear condensation products of ε‐aminocaproic acid of a low degree of condensation, H[NH(CH2)5CO]xOH x = 3, 4 and 5, are described. The purification of these compounds has been accomplished by means of chromatographic adsorption.
The rate of hydrolysis of some p‐nitrophenol esters of ortho‐phosphoric‐ and thio‐phosphoric acid
Authors: Ketelaar J. A. A. , Gersmann H. R. , Koopmans K. 
Published: September 2010

AbstractThe rate of alkaline hydrolysis of some p‐nitrophenyl esters of ortho phosphoric and thiophosphoric acid has been investigated at different temperatures. The energies of activation have been computed. All results can be read from table II.
On the tuberculostatic activity of the thiazole carboxylic acid hydrazides
Authors: Beyerman H. C. , Bontekoe J. S. 
Published: September 2010

AbstractThe high anti‐tuberculosis activity of pyridine‐4‐carboxylic acid hydrazide (isonicotinic acid hydrazide, INH), together with the chemical similarity of pyridine and thiazole, has induced us to synthesize the thiazole carboxylic acid hydrazides and to investigate their possible effects upon Mycobact. tuberculosis.The chemical structure/biological activity relationship is extensively discussed.In agreement with the hypothesis, thiazole‐2‐carboxylic acid hydrazide in in vitro and in in vivo tests proved to be of equal tuberculostatic activity to pyridine‐2‐carboxylic acid hydrazide (picolinic acid hydrazide); they almost completely inhibited the development of experimental tuberculosis in mice.
Synthesis and reactivity of 5‐chloro‐2,4‐dihydroxypyridine
Authors: Kolder C. R. , den Hertog H. J. 
Published: September 2010

AbstractA synthesis of the 5‐chloro‐derivative of 2,4‐dihydroxypyridine is described. In addition to this compound, 5‐chloro‐2‐ethoxy‐4‐hydroxypyridine, 5‐chloro‐4‐ethoxy‐2‐hydroxypyridine, and 5‐chloro‐2,4‐diethoxypyridine were prepared.The reactivity of 5‐chloro‐2,4‐dihydroxypyridine towards bromine and aqueous solutions of hydrobromic and hydrochloric acid has been examined.
Oxydation de thiophènes en sulfones propriétés du groupe sulfonyle XXXIV
Authors: Melles J. L. , Backer H. J. 
Published: September 2010

AbstractLa difficulté d'obtenir des sulfones par oxydation de thiophènes a deux causes: la stabilité du groupement électronique dans L'anneau “aromatique” de thiophène et L'abaissement de cette stabilité par suite de L'oxydation du soufre. Ce mémoire étudie L'influence de substituants sur la possibilité de préparer des sulfones.
Synthetic anticoagulants. I. 1‐Alkoxy‐2,2‐bis‐(4‐hydroxy‐coumarinyl‐3) ethanes
Authors: Veldstr H. , Wiardi A. P. W. , Alberda G. 
Published: September 2010

AbstractNew synthetic anticoagulants were obtained in the series of 1‐alkoxy‐2,2‐bis‐(4‐hydroxy‐coumarinyl‐3)ethanes (III). In the rabbit the most active members of this group are as active as dicoumarol (I), while they equal ethyl biscoumacetate (II) with respect to resorption and rapid elimination. Clinical investigations are in progress.
Phosphatide acids and derivatives: I. Synthesis of phosphatidic acids derived from glycol, starting from monoacylglycols
Authors: van der Neut J. H. , Uhlenbroek J. H. , Verkade P. E. 
Published: September 2010

AbstractIn the presence of pyridine or quinoline monoacylglycols and diphenyl chlorophosphate react smoothly at room temperature, with the formation of acylglycolphosphoric acid diphenyl esters. Upon hydrogenolysis the latter substances yield the acylglycolphosphoric acid and cyclohexane.Some properties of these new types of compounds are discussed.
The activation of chymotrypsinogen
Authors: Mars P. H. 
Published: September 2010

AbstractKunitz and Northrop1) found that a small amount of non‐protein‐Nitropen (N.P.N) was formed during slow activation of chymotrypsinogen by trypsin. No conclusion was drawn whether or not the appearance of N.P.N. coincided with the formation of α‐chymotrypsin. Butler2) repeated their experiment, using higher concentrations of trypsin in order to speed up the activation. He concluded that no N.P.N. was formed during rapid activation. Jacobsen3) also employed rapid activation in his investigations, and he found that hydrolysis consisted of two steps: first, π‐chymotrypsin was formed and, secondly, δ‐chymotrypsin. The amount of N.P.N. released during conversion was ascribed to a side reaction.In the present work the slow activation of chymotrypsinogen was investigated chromatographically. The chymotrypsinogen used was dialysed at pH 3.0, and was found to contain neither peptides nor amino‐acids. The products of slow activation were chromatographed, and several spots appeared. One was due to a peptide. This peptide contains arginine, since the spot gave a positive Sakaguchi reaction.The peptide was isolated and analysed by paper chromatography, and was found to consist of: arginine, lysine, alanine, serine, glutamic acid, and phenylalanine. Faint spots were also found at the places of threonine, aspartic acid, glycine, and methionine.On the other hand, in rapid activation the peptide spot appeared much later than the other spots. This agrees with Jacobsen's finding that the formation of δ‐chymotrypsin exceeds the formation of α‐chymotrypsin during rapid activation.Desnuelle4) found no dinitrofluorobenzene‐reactive N‐terminal groups in chymotrypsinogen, but he did find two such groups in α‐chymotrypsin.According to Neurath et al.5) leucine (or isoleucine) and tyrosine occupy C‐terminal positions in α‐chymotrypsin. This, in conjunction with the substrate specificity of trypsin and carboxypeptidase, led them to the conclusion that a peptide containing lysine or arginine is split off during the conversion of chymotrypsinogen. Our findings are in agreement with their hypothesis.A detailed study will be published later.
Phosphatide acids and derivatives: III. The behaviour of glycerophosphatidic acids towards alkali
Authors: Uhlenbroek J. H. , Verkade P. E. 
Published: September 2010

AbstractBoiling α‐glycerophosphatidic acids with alcoholic sodium hydroxide gives only glycerol‐α‐phosphoric acid, whereas from β‐glycerophosphatidic acids only glycerol‐β‐phosphatidic acid is formed. It is pointed out that esters of these phosphatidic acids behave quite differently.
Complex ‐ chlorides II: Conductometric titration of PCl5 ‐ compounds
Authors: Groeneveld W. L. , Zuur A. P. 
Published: September 2010

AbstractThe existence of POCl3‐complexes of complex‐forming chlorides (e.g. SnCl4, TiCl4, SbCl5), combined with the precipitation method in POCl3for the preparation of PCl5‐compounds 1). strongly creates the impression that there might be an analogy between the H2O and the POCl3 systems. It is known that hydrates of complex‐forming chlorides are decomposed by e.g. CsCl2CsCl + SnCl4 · nH2O → Cs2SnCl6 + n H2O2 PCl5 + SnCl4 · n POCl3 → (PCl4)2SnCl6 + n POCl3In order to get some information about the possibility of this process, the system POCl3‐PCl5‐complex‐forming chloride is investigated by conductometric titration.
Steric effects on mesomerism: XI, The ultra‐violet absorption spectrum of Tröger's base and the stereochemistry of aromatic amines
Authors: Wepster B. M. 
Published: September 2010

AbstractA careful analysis of molecular models shows that in Tröger's base (I) the configuration of the two aniline systems can be described as skewpyramidal with an angle of twist of 45°. The ultra‐violet spectrum of this compound reveals that in this configuration the mesomeric interaction between the benzene ring and the amino group is by no means eliminated. The consequences of this are discussed with respect to the connection between spatial configuration and mesomerism in aromatic amines, and are placed on a semi‐quantitative basis by comparison of oscillator strengths.The results obtained are utilized in a fairly detailed discussion of the stereochemistry of aromatic amines. Configurations with pyramidal nitrogen appear to be definitely more favourable from an energy point of view than configurations with planar nitrogen.
The calculation of the specific refraction of tri‐n‐alkylalkoxysilanes
Authors: Breederveld H. , Waterman H. I. 
Published: September 2010

AbstractThe specific refraction (r) of tetra‐n‐alkylsilanes and tetraalkoxysilanes can be calculated very accurately by adding the respective group refractions according to Smith1) 2) and dividing the obtained molar refraction (M) a) by the molecular weight. If this method is used to calculate the specific refraction of silanes containing groups of different types, deviations are said to occur. In agreement with this principle, which holds in general and can be explained on the ground of the English theory3), the present authors found that the specific refractions of tri‐n‐alkylalkoxysilanes are in general lower than the calculated values. This decrease of the specific refraction is caused by the fact that alkoxy groups have greater electron‐attracting properties than alkyl groups, which will be discussed.
On the reaction of phenylbutadiene with formaldehyde
Authors: Beets M. G. J. , Drukker E. A. 
Published: September 2010

AbstractThe reaction of trans‐1‐phenylbutadiene‐1.3 with aqueous formaldehyde solution in the presence of an acid catalyst has been studied. The main reaction product is shown to be trans‐4‐styryl‐m‐dioxane. The structure and properties of both this compound and its hydrogenation product are discussed.
The heats of adsorption of hydrogen on Ni‐SiO2 catalysts
Authors: Schuit G. C. A. , de Boer N. H. 
Published: September 2010

AbstractThe heats of adsorption of hydrogen on several Ni‐SiO2 catalysts were determined from the dependence of the amounts adsorbed on the pressure and the temperature. Three systems were investigated: a sample obtained by reduction of an imperfectly crystallized Ni‐montmorillonite, a coprecipitate and an impregnation catalyst. The three systems were only found to differ in the total amounts of hydrogen adsorbed. The following equation was found to apply for temperatures between 195° K and 673° K and pressures from 0.1 to 100 mm Hg.\documentclass{article}\pagestyle{empty}\begin{document}$${\rm RT}\ln {\rm p}({\rm atm}) + {\rm T}\left\{ {\frac{{\mu _{\,{\rm T}}^ \circ - {\rm h}_{\, \circ }^ \circ }} {{\rm T}}} \right\} - 2{\rm RT}\ln \frac{{\Theta _{\rm H} }} {{1 - \Theta _{\rm H} }} = - 24.000 + 14.400\Theta _{\rm H} {\rm cal}\,{\rm mole}^{ - 1}$$\end{document}In this equation μ°T‐° °/T is the “free energy function” of gaseous hydrogen and ΘH is the fractional coverage assuming total coverage at 195° K and 1 atm.Heats of adsorption deduced from this equation were found to be 5 kcal/mole−1 lower than those reported for Ni‐films, but higher than others reported for nickel obtained by reduction. The possible causes of these differences are discussed.
The influence of the refractive index on the absorption of light by solutions
Authors: Schuyer J. 
Published: September 2010

AbstractStarting from the theory of Onsager‐Böttcher a new formula is derived by which the influence of the refractive index on the molar extinction coefficient of a solution can be calculated.As this formula is rather complicated, approximation formulae are given for certain types of solutions. These formulae prove to be in better agreement with experiments than the formula of Chako‐Kortüm.
The Raman and infrared absorption spectrum of selenophene
Authors: Gerding H. , Milazzo G. , Rossmark H. H. K. 
Published: September 2010

AbstractThe Raman frequencies of liquid selenophene are communicated here. The infrared absorption bands of liquid selenophene have been determined in the region 1600‐670 cm−1 mainly, using a Perkin Elmer instrument with a rock salt prism and by Dr. Lecomte in Paris for the lower frequency region (about 390‐600 cm−1), making use of a grating spectrometer. Quantitative depolarization ratios were determined for the not too weak Raman lines.Selenophene has a non‐planar configuration with only one symmetry plane remaining (symmetry C15). A striking analogy exists between many features of the vibrational spectra of selenophene and thiophene.
Preparation of 4‐nitro‐2,6‐xylidine
Authors: Kloosterziel H. 
Published: September 2010

Abstract4‐Nitro‐2,6‐xylidine (4‐nitro‐2,6‐dimethylaniline) has been obtained by the interaction of ammonia and 4‐nitro‐2,6‐xylenol (4‐nitro‐2,6‐dimethylphenol), an easily accessible compound.