bluuebunny/crossref_metadata_2025 huggingface dataset:
On the quantitative analysis of gas mixtures, which contain nitrogen as well as the various oxides of nitrogen
Authors: Meyer G. , Voogel P.
Published: September 2010

A method has been worked out to determine nitrogen in the presence of the various oxides of nitrogen by the processes of gas analysis. According to this method, the gas is divided into three fractions, which consist respectively of nitrogen, nitrogen peroxide and a mixture of nitrous oxide and nitric oxide, after which the two latter fractions are analysed. The volumetric determination of gases, which contain nitrogen peroxide, is not required for this analysis.

We believe that the accuracy of the method described by us is certainly not worse than that of the customary titrimetric methods of determination.
O‐hetero‐analogues of steroids
Authors: Bolt C. C.
Published: September 2010

Several 1,2‐cyclopentano‐2,5‐dimethyldecalone‐6‐propionic acid‐5 derivatives have been prepared by ozonization of ▵4‐3‐ketosteroids, followed by reduction with sodium and ethanol, yielding hydroxycarboxylic acids. In neutral or acid solution ring closure occurs to the lactones. The resulting 4‐oxa‐3‐ketosteroids probably have the cholestane configuration. This group of substances crystallize readily from the usual organic solvents.
Investigations on organic fungicides: V. Chemical constitution and fungistatic activity of aliphatic bisdithiocarbamates and isothiocyanates
Authors: Klöpping H. L. , van der Kerk G. J. M.
Published: September 2010

In this paper, the investigations on the relations of structure to antifungal activity of sulphur compounds described in the previous publication of this series are extended to bisdithiocarbamates and isothiocyanates. The most active sulphur fungicide described in the literature so far, disodium ethylenebisdithiocarbamate, is surpassed by a new fungicide mentioned below, viz. ethylene diisothiocyanate. It is suggested that the antifungal action of bisdithiocarbamates is primarily attributable to the formation in situ of the corresponding diisothiocyanates.
On the reactions of the lithium compound of 2,6‐dimethylpyridine with benzyl chloride, benzoic anhydride or benzonitrile
Authors: de Jong J. I. , Wibaut J. P.
Published: September 2010

When 2 mol. of phenyllithium are allowed to react with 1 mol. of lutidine and the mixture is then treated with an excess of benzyl chloride, α‐methyl‐α′‐(dibenzyl‐methyl) pyridine (I) is produced along with α‐methyl‐α′‐phenylethylpyridine (VI). The statement of Bergmann and Rosenthal, that α,α′‐bis‐(phenylethyl)pyridine (II) should be produced in this reaction, is incorrect.

When 2 mols. of phenyllithium are allowed to react with 1 mol, of lutidine and the product is treated with an exces of benzoic anhydride, a derivative of lutidine is produced, which, contrary to the opinion of Kloppenburg and Wibaut, is to be considered as the benzoate of the enol form of 2‐phenacyl‐6‐methylpyridine (VIIb).

(VIII). By the interaction of 2 mols. of phenyllithium and 2 mols. of

The action of 1 mol. of phenyllithium and 1 mol. of benzonitrile on 1 mol. of α,α′‐lutidine leads to the formation of 6‐methyl‐2‐phenacylpyridine (VIII). By the interaction of 2 mols of phenyllithium and 2 mols of benzonitrile on 1 mol. of α,α′‐lutidine, a complicated reaction takes place with the formation of a compound C21H19N3, to which a tricyclic structure (XI) is ascribed.
Kinetical experiments on ozonisation reactions: I. Apparatus
Authors: Boer H. , Sixma F. L. J.
Published: September 2010

A description is given of the apparatus used for the kinetic measurements on ozonisation reactions described in part II1).

A constant stream of a mixture of ozone and oxygen of variable but constant (within 3‰) composition is electrolytically generated by a stabilized generating device.

A thermostat suitable for temperatures between 0° and −70° C, varying within 0.04° C, is described.

The solubility of ozone in chloroform has been determined.
Preparative chromatographic separation of glycine, sarcosine and dimethylglycine using starch
Authors: Sluyterman L. A. Æ. , Veenendaal H. J.
Published: September 2010

Glycine, methylglycine (sarcosine) and dimethylglycine can be quantitatively separated in starch columns using water‐alcohol 2:1 (v/v) as eluting agent. If amino acid hydrochlorides are to be separated, the eluting agent must be acidified with HCl.

Likewise the partial separation of some peptides has been achieved by applying water‐alcohol 2:1.
Etude Spectrographique et Thermogravi‐Metrique de Quelques Antimoniates
Authors: Dupuis Thérèse
Published: September 2010

Cette étude porte sur les antimoniates de potassium, sodium, baryum, argent et plomb, considérés à l'état solide, à froid, et après déshydratation par chauffage. Pour chacun d'eux, on a enregistré le spectre d'absorption infrarouge, entre 600 et 2000 cm−1 et la courbe de thermolyse, entre 20° et 1000° C, afin, 1° de vérifier la formule de Pauling pour les produits non chauffés, 2° de connaitre la structure des corps qui en dérivent par chauffage.
Etude des Produits de Condensation du Benzaldehyde Avec la Methylamylcetone et la Methylisobutylcetone
Authors: Metayer Maurice
Published: September 2010

L'auteur étudie la condensation du benzaldéhyde sur la méthylisobutylcétone et la méthylamylcétone. Les propriétés chimiques des styryl‐alkyls cétones obtenues sont investies.
Reaction products of primary β‐hydroxy‐amines with carbonyl compounds. II. Molecular refraction and infrared spectrum
Authors: Bergmann Ernst D. , Zimkin E. , Pinchas S.
Published: September 2010

The condensation of a number of carbonyl compounds with ethanolamine and with amino‐alcohols having a tertiary hydroxy‐ and a primary amino‐group, has been studied. The molecular refraction and the infrared spectrum have been used to distinguish between the oxazolidine and Schiff's base structures which are both possible for the condensation products.

Aromatic and α,β‐unsaturated carbonyl compounds, on the whole, tend to form Schiff's bases, saturated carbonyl compounds oxazolidines, with ethanolamine. Introduction of C‐alkyl groups into the ethanolamine system favours the formation of oxazolidines even with aromatic aldehydes and ketones.

In the infrared spectrum of simple CN‐compounds in alcoholic solution, a solvation effect has been observed. Also, the tautomerisability of substances containing the system CH−1—CN, to HC  C—NH has been demonstrated.

The (non‐conjugated) CN double bond absorbs in the infrared at about 1670 cm−21 whilst the oxazolidine system is characterised by three bands (1149—1185; 1116—1139; 1086—1118 cm−1) in the 1100—1200 cm−1 region.

The similarity of the infrared spectra of all heterocyclic substances of the general type magnified image is stressed.
Reaction products of primary β‐hydroxy‐amines with carbonyl compounds. IV. Infrared and ultraviolet absorption spectra of ethylenediamine derivatives
Authors: Bergmann Ernst D. , Meeron E. , Hirshberg Y. , Pinchas S.
Published: September 2010

Eight ketones and p‐chlorobenzaldehyde have been condensed with ethylenediamine. Only cyclohexanone and its methyl‐derivatives give imidazolidines; in all other cases, double Schiff's bases are formed. The assignment of structures is based on the infrared spectrum.

The infrared spectra of two hexahydropyrimidine derivatives have been studied for the sake of comparison.

The ultraviolet spectra of the double Schiff's bases have been measured.

The similarity in the infrared spectrum of 1,3‐dioxolanes, oxazolidines, imidazolidines and thioxolanes is stressed. Two representatives of the last class of compounds have been prepared and their physical properties studied.
Reaction products of primary β‐hydroxy‐amines with carbonyl compounds. VII. Oxazolidines derived from N‐methylethanolamine
Authors: Bergmann Ernst D. , Zimkin E. , Pinchas S.
Published: September 2010

The preparation of ten N‐methyloxazolidines, their molecular refraction and infrared absorption spectrum are reported. The molecular refractions show a depression which is ascribed to the oxazolidine ring. The infrared absorption spectra consist of a number of bands in the 1050–1190 cm−1 region, characteristic of the magnified image group and the tertiary nitrogen.
Reaction products of primary β‐hydroxy‐amines with carbonyl compounds: VIII. Variation thermique de la réfraction moléculaire
Authors: Metzger Jacques
Published: September 2010

Deux problèmes de tautomérie posés par l'étude expérimentale de certains dérivés de condensation de β‐hydroxyamines primaires avec des composés carbonylés sont envisagés à la lumière de la technique réfractométrique. L'étude de la Réfraction Moléculaire (R.M.) à 20° permet de confirmer l'hypothèse de cette tautomérie. La variation thermique de cette R.M. ajoute un argument supplémentaire et permet de prévoir le sens de l'évolution de la tautomérie en fonction de la température. Un mécanisme raisonnable est proposé pour expliquer cette transformation tautomère.
Thermal quantities of some cycloparaffins. Part III. results of measurements
Authors: Kaarsemaker Sj. , Coops J.
Published: September 2010

The heats of combustion, melting points, heats of fusion, boiling points, refractive indices and in four cases the densities have been determined on selected samples of the cyclanes with 4 to 9 C‐atoms; some hitherto unknown transition points were discovered and the heats of transition measured. The heats of vaporisation at 25° are estimated. Results of the measurements are discussed.
Reductive alkylation of 2‐aminopyridine and 2‐aminopyrimidine
Authors: Kaye Irving Allan , Kogon Irving C.
Published: September 2010

N‐Monosubstituted 2‐aminopyridines are formed in high yield when the corresponding Schiff bases are refluxed in formic acid‐cumene solution. For the preparation of N‐monosubstituted 2‐aminopyrimidines, refluxing 2‐aminopyrimidine and an aldehyde in formic acid seems preferable. The products are readily purified, and yields are increased by vacuum distillation followed by recrystallization. A procedure which is satisfactory for the preparation of 2‐aralkylideneaminopyridines gives N,N′‐benzilidene‐bis‐2‐aminopyrimidine from benzaldehyde and 2‐aminopyrimidine.
Preparation and ultraviolet absorption spectrum of meta‐nitroisopropylbenzene
Authors: Biekart H. J. B. , Verkade P. E. , Wepster B. M.
Published: September 2010

The preparation and the ultraviolet absorption spectrum of meta‐nitro‐isopropylbenzene are described.
Hydrolyse et Aminolyse DBS 1,1,1,1‐Disulfure‐Disulfones. (Propriétés du groupe sulfonyle XXVI)
Authors: Backer H. J.
Published: September 2010

Après l'étude de l'hydrolyse de (CH3S)2C(SO2CH3)22) on a examiné les dérivés portant un ou plusieurs groupes phényle au lieu de méthyle.

L'hydrolyse acide de ces composés conduit à des esters de l'acide dithiocarbonique; outre des esters connus on a obtenu ainsi le di‐ester mixte de méthyle et de phényle.

L'hydrolyse basique expulse un groupe méthylthio ou phénylthio. qui est reraplacé par l'hydrogène. Lorsque les deux fonctions thioéther ne sont pas égales, l'hydrolyse s'accomplit en deux directions.

La pipéridinolyse réussit dans la plupart des cas aisément avec dégagement de chaleur. Pour les composés à deux fonctions thioéther différentes, la préférence entre les deux groupes diffère de celle observée pour l'hydrolyse alcaline.
The use of glass electrodes for the measurement of activities of metal ions
Authors: van Schuylenborgh J. , Vervelde G. J.
Published: September 2010

Glass electrodes of the “mixed electrode” type can be used with advantage to measure activities of metal ions in systems of known pH, containing only one kind of metal ions. The use of a valve electrometer adapted to very high input resistances made it possible to use robust bulb electrodes of a high chemical and electrical resistance. These electrodes appeared to be very suitable for this purpose and produced remarkably reproducible figures.

The relationship between the potentials measured and the ion concentrations was examined theoretically and found to be in agreement with the assumption, that glass behaves as a weak acid and that the potentials are essentially membrane potentials in a Donnan system.
Arenicochrome, a new pigment from arenicola marina L: Isolation and composition
Authors: van Duijn P.
Published: September 2010

Arenicochrome, a green granular pigment in the epithelial cells of Arenicola marina L., first described histologically and histochemically by Lignac, was extracted from the worm by means of ammoniacal alcohol containing cyanide. After chromatography on aluminium oxide, crystallization of the pigment as a potassium salt was achieved. The formula of this salt proved to be (C21 H15 S2 O14 K3)n where n = 1 or n = 2. Of the three salt‐forming groups (minimum formula) one has a pK of 5.7; the dissociation of this group is accompanied by a colour‐shift from orange to blue. The two remaining groups are of a strong acid character. The absorption spectra of the compound at different pH values are reported. Some biological problems resulting from the investigation are briefly discussed. In addition some other properties of he pigment are mentioned.
The adsorption of nitrogen, hydrogen and their mixtures on silica gel
Authors: van der Waarden M. , Scheffer F. E. C.
Published: September 2010

Adsorption isotherms of hydrogen and nitrogen on silica gel were determined up to equilibrium pressures of approx. 800 mm mercury and at temperatures between +300 and —195°C. The adsorption of nitrogen‐hydrogen mitxures at a total equilibrium pressure of 760 mm mercury was determined at 0, —78 and —183°C.

At 0 and —78°C the adsorption of hydrogen is increased by the presence of nitrogen and the adsorption of nitrogen is reduced by the presence of hydrogen; at —183°C the adsorption of hydrogen is strongly reduced by the presence of nitrogen and the adsorption of nitrogen is hardly affected by the presence of hydrogen.

The adsorption at temperatures above the critical temperature of the individual gases, as well as that of their mixtures is qualitatively in agreement with the conception that the adsorbed phase is a gas phase condensed under the influence of the adsorbent.
The redox potential as a critical factor in the hill reaction
Authors: Wessels J. S. C. , Havinga E.
Published: September 2010

The photochemical reduction of various quinones and dyes by water in the presence of chloroplasts was studied by measurement of the redox potential during illumination. Whether this Hill reaction will proceed to a measurable degree appears to be determined by the standard potential of the redox substance. With systems having a standard potential of about 40 millivolts

Redox potentials in this paper are given with reference to the normal hydrogen electrode at pH = 6.5, and if possible at a temperature of 16° C.

or lower, no reduction was observed.
The properties of a number of cyclic olefins
Authors: van der Bij J. R. , Kooyman E. C.
Published: September 2010

A number of cyclic olefins having six, seven or eight carbon atoms were prepared and some of their properties investigated.

The olefins were synthesized by pyrolysis of acetates; olefin contents were determined by means of the ozone addition method. Purities were investigated by ozonolyses, separating and isolating the carbonyl compounds formed by chromatography of the 2,4‐dinitrophenylhydrazones.
The quantum yield of the photo‐decomposition of some aromatic diazonium salts
Authors: de Jonge J. , Dijkstra R. , Wiggerink G. L.
Published: September 2010

The quantum yield of the photo‐decomposition of some aromatic diazonium salts in solution is estimated, using light with a wavelength of 3650 Å.

The photo‐decomposition of phenyl‐amino benzene diazonium sulphate is proposed as a suitable actinometer.

The quantum yield of the photochemical isomerisation of stable p‐methoxy‐benzenediazo‐cyanide was found to be about 0.35.
The dehydrogenation of hydrocarbons by means of quinones. II. Kinetics of the reaction with chloranil; dehydrogenations with other quinones
Authors: Dost N.
Published: September 2010

The dehydrogenation of hydrocarbons by means of tetrachloro‐p‐benzo‐quinone (chloranil) was found to proceed according to the overall equation: hydrocarbon + quinone → dehydrogenated hydrocarbon + hydroquinone. The kinetic order of the reaction proved to be bimolecular. The rate of reaction depended on the concentration of hydrocarbon and of quinone.

A correlation was found to exist between the oxidation‐reduction potentials of a number of substituted quinones and their activity in the dehydrogenation of tetralin to naphthalene.
A investigations in the vitamin A‐series. II. Allylic rearrangements in the vitamin A‐series
Authors: Huisman H. O. , Smit A. , Vromen S. , Fisscher L. G. M.
Published: September 2010

By splitting off water from the intermediate hydroxy‐compounds in the Vitamin A‐series allylic rearrangement takes place into the cyclohexene ring. This rearrangement occurs throughout the whole Vitamin‐A‐series‐ with those hydroxy‐intermediates wherein the hydroxy‐group is in an allyl position with regard to the double bond in the cyclohexene ring.

The reason why so many attempts to prepare synthetic Vitamin A in reasonable yields, starting with “key” intermediates other than the C14aldehyde, lead to a failure, has been outlined.
Trityl derivatives of amines: I. N‐trityl derivatives of aromatic primary amines
Authors: Verkade P. E. , Nijon H. , Tollenaar F. D. , van Rij J. H. , van Leeuwen M.
Published: September 2010

The reaction of aromatic primary amines with trityl chloride at room temperature and in the presence of an excess of pyridine as a rule leads to N‐trityl derivatives.
Sur L'activité Optique D'échantillons de Mimosine (Leucaenol) de Provenance Différente
Authors: Wibaut J. P. , Schuhmacher J. P.
Published: September 2010

Un échantillon de leucaenol qui a été isolé, dans le temps, par Mascré des graines de Leucaena glauca B, provenant de Cochinchine, et que cet auteur décrit comme optiquement inactif est, d'après nos observations, lévogyre: [α]D22=−20°. Cet échantillon est identique ä un échantillon de mimosine (leucaenol) que nous avons isolé des graines de Leucaena glauca B provenant de Java.
Quelques Thiolsulfonates de Trichloro‐Méthyle. (Propriétés du groupe sulfonyle XXVIII )
Authors: Backer H. J. , Westerhuis E.
Published: September 2010

Le chlorure trichlorométhanesulfénique CCl3SCl réagit aisément sur les sulfinates de sodium en donnant naissance à des thiolsulfonates de trichlorométhyle: RSO2SCCl3. Plusieurs composés décrits dans nos trois mémoires présentent des propriétés fungicides.
Free‐radical reactions involving sulphur compounds. I. The interaction of 2‐cyano‐2‐propyl radicals and thiols
Authors: Bruin P. , Bickel A. F. , Kooyman E. C.
Published: September 2010

The reaction of thiols (R'SH) with 2‐cyano‐2‐propyl radicals (R), generated by thermal decomposition of 2,2′‐azoisobutyronitrile (RN = NR), was investigated.

The radicals (R) readily abstract a hydrogen atom from the thiol (R'SH), producing isobutyronitrile (RH) and thiyl radicals (R'S), whilst their dimerisation product, tetramethylsuccinonitrile (RR), is also formed in appreciable quantities. Using primary, secondary and tertiary thiols respectively, decreasing yields of isobutyronitrile (RH) and increasing yields of tetramethylsuccinonitrile (RR) were obtained. This indicates that the reactivity of thiols towards R decreases in the same order. There appeared to be little difference between toluene‐α‐thiol and n‐octane‐1‐thiol.

The thiyl radicals (R'S) combine to form disulphide (R'SSR') and with 2‐cyano‐2‐propyl radicals (R), to form mixed sulphides (R'SR). The latter are formed in far lower yields than both the disulphides and tetramethylsuccinonitrile. This phenomenon may be related to the fact that the CS bond is weaker than could be expected from the energies of the CC and SS bonds.
On the use of matrix‐like arrays as chemical symbols
Authors: Zernike J.
Published: September 2010

The isomorphous replacement of two elements simultaneously by two others is symbolized by a square matrix. Again three such matrices, representing the cyclic replacement of two elements out of three by two others, may be contracted into one matrix of three columns and two rows. In all these the coordinative binding of aluminium is indicated by its place.

These symbols may be combined with one another, or with existing symbols concerning the isomorphous replacement of one element by one other. Thus a clear survey of silicate chemistry is obtained.

By placing appropriate coefficients above the columns of the matrix, a particular mixed crystal may be represented. On the strength of this, an opinion is advanced as to the most probable composition of sarcolite.
Dérivés 9‐Méthylthio et 9‐Méthylsulfonyle du Thioxanthène‐10‐Dioxyde et leur Hydrolyse: Propriétés du groupe sulfonyle XXX
Authors: Kloosterziel H. , van der Veen W. , Backer H. J.
Published: September 2010

Ayant complété la série des thioxanthène‐10‐dioxydes, substitués en position 9 par des groupes méthylthio et méthylsulfonyle, les auteurs ont étudié l'hydrolyse acide et basique de ces composés, qui peuvent être envisagés comme des vinylogues de 1,1‐disulfones substituées.
La Réaction de L'Anhydride Sulfureux et du Dioxyde de Sélénium sur le Diphényl‐Diazomethane . Propriétés du groupe sulfonyle XXXI
Authors: Kloosterziel H. , Backer H. J.
Published: September 2010

Le diphényldiazométhane réagissant avec SO2 fournit la tétraphényléthènesulfone, qui, par l'intermédaire d'un radical bivalent, subit un élargissement de l'anneau sulfonique en donnant naissance, selon le solvant, soit au 1,1,3‐triphényl‐1,7a‐dihydro‐isothionaphtène‐2,2‐dioxyde jaune (III), soit au 1,1,3‐triphényl‐1,3‐dihydro‐isothionaphtène‐2,2‐dioxyde (IV) incolore. La décomposition thermique de ces deux sulfones (III, IV) conduit, avec élimination de SO2, au 9,9‐diphényl‐9,10‐dihydro‐anthracène (V) et au 9,10‐diphényl‐9,10‐dihydro‐anthracène (XIII).
Electrochemical behaviour of ion‐exchanging substances.: VI. potential measurements on plant roots and the amphoteric nature of the root substance
Authors: Vervelde G. J. , Tendeloo H. J. C.
Published: September 2010

Potentials measured on plant roots in media of varying acidity reverse their sign at a certain pH usually lying in or near the range 3 to 3.5. The value of this pH depends on the plant species. The reversal is explained by the amphoteric character of the root substance. If the root substance carries more dissociated acidoid than dissociated basoid groups, the root potential, pictured as a membrane potential in a Donnan system, will be negative. If there is a surplus of basoid dissociated groups, the potential will be positive. In the intermediate case, where equal numbers of both groups are present, there is no potential because the conditions for a Donnan system are absent. Quantitatively, the electrical behaviour of the amphoteric root substance can be satisfactorily described by assuming a linear relationship between its net acid‐ or base‐binding capacity and the pH.
The formation of trimethylol urea
Authors: De Jong J. I. , De Jonge J. , Eden H. A. K.
Published: September 2010

In concentrated aqueous solution and in the presence of an excess of formaldehyde more than two methylol groups may be attached to one molecule of urea. The equilibrium constant of the formation of trimethylol urea is evaluated.
The Hofmann degradation of 4‐hydroxy‐phthalimide
Authors: van der Stelt C. , Suurmond B. G. , Nauta W. Th.
Published: September 2010

According to Rodionow and Fedorowa1), Hofmann degradation of 4‐hydroxy‐phthalimide yields 2‐amino‐4‐hydroxy‐benzoic acid. This has been shown to be incorrect. Only 2‐amino‐5‐hydroxy‐benzoic acid could be isolated from the reaction mixture. The spectra of both the acids mentioned were measured, and a few derivatives were prepared.
The hydrolysis of methylene diurea
Authors: de Jong J. I. , de Jonge J.
Published: September 2010

The hydrolysis of methylene diurea giving urea and monomethylolurea was found to be a monomolecular reaction. The rate of the reaction is directly proportional to the hydrogen ion concentration in the pH range measured (3‐5) and independent of the buffer concentration. The activation energy appeared to be 19.5 kcal.

Generally, the reaction of an amidomethylol group with an amide group leading to the formation of a methylene bridge between urea fragments, will be a reversible reaction. The rates of both the forward and the reverse reactions are proportional to the hydrogen ion concentration.
The reaction of methylene diurea with formaldehyde
Authors: de Jong J. I. , de Jonge J.
Published: September 2010

The reaction of methylene diurea with formaldehyde showed a close resemblance to the previously studied reaction of urea and formaldehyde1), i.e. the reaction appeared to be bimolecular and the rates were found to be directly proportional to the concentration of hydroxyl ions while further an influence of the buffer concentration on the rates was observed. Obviously the reaction is subject to a general acid and/or base catalysis. The activation energy appeared to be about 15 kcal/mol. The values for the rate constants were almost the same as were found for the reaction between urea and formaldehyde.
Rayonne‐viscose ‐ role physico‐chimique des bains de regeneration
Authors: Pariaud Jean‐Charles , Ferrier Jean
Published: September 2010

L'influence des concentrations des bains acides, sur le processus de régénération de la cellulose à partir de la viscose a été éxaminée. La méthode statique employée, en dehors de la filature, est basée sur la mesure de L'épaisseur de la couronne de cellulose, apparaissant lorsqu'on trempe un cylindre de viscose dans ces bains. On propose une interprétation du phénomène.
Etude physico‐chimique de la vagotonine: I. Électrophorèse
Authors: Michel G. F.
Published: September 2010

L'hétérogénéité de la vagotonine a été signalée par quelques auteurs. Nous avons étudié le comportement de cette substance et des différentes fractions isolées par précipitation saline, à L'électrophorèse et à L'ultracentrifugation.
On the theory of aromatic substitution: I. A theoretical treatment of the effect of poles and dipoles on the substitution type
Authors: Sixma F. L. J.
Published: September 2010

The method previously described

This is the second of a series of communications on the influence of substituents on the reactivity of aromatic compounds. For the first communication cf: F. L. J. Sixma, J. Chem. Phys. 19, 1209 (1951).

for calculating the influence of the electric field of a substituent (inductive effect) on the energy content of the intermediate complex of substitution reactions in the benzene nucleus, proceeding from the known values of dipole moments, bond lengths and valency angles, is further elaborated.

The theory is tested on the experimental results for electrophilic substitution reactions. The agreement between calculated and experimental values for the percentage meta‐substitution is very satisfactory for those substituents which show little or no resonance interaction (E‐effect) with the pentadienate cation.
The reactivities of alpha methylenic groups towards free radicals: III. Steric effects in tetralin, indan and dihydroanthracene derivatives
Authors: Kooyman E. C. , Strang A.
Published: September 2010

The relative reactivities towards trichloromethyl radicals were determined for a number of tetralin, indan and dihydroanthracene homologues, using the retardation method described previously 1) 2).

As in the case of alkylbenzenes 2), several of the hydrocarbons showed marked decreases in reactivity compared with the additive values. The effects are again attributed to steric interference with the most favourable transition state configuration. They were found to become increasingly important in the order (1‐methylindan, hexahydrofluorene), 1,4,7‐trimethylindan, (cumene, 1‐methyltetralin, 9,10‐dimethyl‐9,10‐dihydroanthracene), 9,10‐diisopropyl‐9,10‐dihydroanthracene, (o‐cymene, hexaethylbenzene, 1,2,4,5‐tetraisopropylbenzene).

The magnitudes of the effects are discussed on the basis of the calculated distances between the centres of the interfering groups in the absence of steric repulsion. This leads to an estimate of the effective methyl radius of about 1.5 Å at angles of approach of about 80°, i.e. a value considerably smaller than the Van der Waals radius (2.0 Å).
Researches on heterogeneous redox‐systems
Authors: Tendeloo H. J. C. , de Vries T. J.
Published: September 2010

Measurements on the redox‐system methylene blue‐leuco‐base of methylene blue in water and the same system containing active carbon lead to the conclusion that adsorbed methylene blue shows markedly different properties. The reduction of adsorbed methylene blue by TiCl3 is hindered.
Phosphatide acids and derivatives: II ). Synthesis of glycerophosphatidic acids, starting from diglycerides
Authors: Uhlenbroek J. H. , Verkade P. E.
Published: September 2010

The present paper describes the synthesis of the seven possible glycerophosphatidic acids (formulae IX‐XII) containing palmitic and/or stearic acid as component acids, by the hydrogenolysis of the corresponding diphenyl esters with hydrogen in the presence of a platinum/active carbon catalyst. The diphenyl esters are obtained by the action of diphenyl chlorophosphate on the monoacid and diacid αβ‐ and αγ‐diglycerides in the presence of an excess of pyridine.

Some properties of the glycerophosphatidic acid diphenyl esters and the glycerophosphatidic acids are described.
Stability of oil‐in‐water emulsions I: The electrical double layer at the oil‐water interface
Authors: van den Tempel M.
Published: September 2010

The electrostatic interaction between charged oil globules in water is determined by the potential drop at the aqueous side of the interface. This potential drop is, under the conditions of the present investigation, practically entirely determined by the amount of adsorbed soap ions and the electrolyte concentration in the aqueous phase. A model is described according to which the charge in the diffuse layer is compensated by the charge of the adsorbed soap anions minus the charge of the counter‐ions situated between the ionic heads of the adsorbed soap ions. The capacity of the double layer in the oil phase may be neglected.

The amount of adsorbed soap ions has been determined by measuring the dependency of the interfacial tension on the soap concentration, followed by application of the Gibbs adsorption isotherm. The potential drop at the aqueous side of the interface has been calculated; it was found to be practically independent on the soap concentration in the range of concentrations investigated. The potential drop is decreased by increasing the salt concentration; the effect of an addition of salt on the potential drop is strongly dependent on the valency of the counter ions.

Determination of the zeta‐potential by measurement of electrophoretic mobility of oil droplets indicates that the values of the surface potential as calculated are of the right order of magnitude.
An exact vapour pressure equation
Authors: Gottschal A. J. , Korvezee A. E.
Published: September 2010

In this paper a general vapour pressure equation is derived from the thermodynamic equilibrium condition. For pressures under or slightly over one atmosphere, where the equation of state

pv = RT + Bp

is valid for the vapour, three correction terms must be added to log p to obtain (log p)corr = −A/T + D. The three correction terms can be calculated from precise specific heat and density data for either phase.

The variation of the heat of vaporization with temperature is shown to depend on the same data.
The second virial coefficient of benzene II
Authors: Korvezee A. E.
Published: September 2010

Recent experimental evidence allows of fixing the constants in the B(T) relation for benzene as given in an earlier paper.

The present expression is supposed to represent this second virial coefficient to within 25 cm3/mole from room temperature to well over the boiling point.
On the mutual stability relationship of MeAn complexes consisting of a metal ion Me and a ligand A in aqueous solution, for consecutive values of n
Authors: van Panthaleon van Eck C. L.
Published: September 2010

The stability of MeAn complexes formed by a metal ion Me and a ligand A in aqueous solution, as a function of consecutive n values is discussed. Literature data constitute the basis of this discussion.

For quite a number of systems it is possible to draw up an equation accurately correlating the stability of the MeAn complex with that of the MeA1 complex and with the n value.
The determination of molecular polarisabilities and effective RADII of some normal alkanes
Authors: Scholte Th. G. , de Vos F. C.
Published: September 2010

Results are given of a number of measurements of the refractive index, dielectric constant and density of some normal alkanes at different temperatures. From the data obtained the radii and the polarisabilities of the molecules are evaluated.
Steric hindrance of resonance in a substituted phenylmethylsulphone: (Properties of the sulphonyl group XXXVIII)
Authors: Kloosterziel H. , Backer H. J.
Published: September 2010

N‐acetyl‐4‐methylsulphonyl‐2,6‐xylidine (I) has been prepared by the convenient method used before, involving thiocyanation of 2,6‐xylidine and reduction of the thiocyano group with LiAlH4, followed by methylation and subsequent oxidation of N‐acetyl‐4‐methylmercapto‐2,6‐xylidine to the corresponding sulphone. The latter compound (I) has an U.V. spectrum intermediate between those of phenylmethylsulphone and N‐acetyl‐p‐methylsulphonylaniline, indicating that the extended resonance is sterically hindered.
Synthesis of some aliphatic β‐amino‐dicarboxylic acids
Authors: Gootjes J. , Nauta W. Th.
Published: September 2010

Three β‐amino‐dicarboxylic acids were prepared by reduction of the corresponding ethyl β‐oxo‐dicarboxylate acetylhydrazones. The melting point and the tuberculostatic activity of β‐amino‐pimelic acid are not in accordance with the data found by Romeo for a compound obtained by hydrogenation of p‐amino‐salicylic acid, which seemed to be β‐amino‐pimelic acid.
An investigation as to the type of particles occurring in concentrated solutions of electrolytes in relation to the hydration of the ions
Authors: van Ruyven B. H.
Published: September 2010

In this communication we make an investigation in the domain of concentrated electrolytic solutions on a larger scale and of a more profound kind than was possible in 19371). Principally use is made of depressions of vapour pressure determined by Tammann, if possible up to a weight‐normal concentration (n ω) = 10.

Raoult's law (in the domain of vapour pressures), combined with ideas of Arrhenius, leads to the calculation of degrees of ionisation. The values found necessitate the assumption of hydration of ions or of ion pairs and ions. Remy determined ion hydrations by a direct method. The literature on the subject was difficult to survey and not very convincing2).

Thus various ideas lead to the study of footnote 1 and of this communication

Can the assumption of ion hydration cooperate in the explanation of the anomalies acknowledged by Arrhenius himself?

Can ion hydrations be calculated in the above way?

Can further insight be obtained that way into the nature of concentrated electrolytic solutions?

We began our exploration at the time without taking into account the effect of forces acting between the ions on the observed depressions of vapour pressure because their total effect could not be calculated. We have now worked up all Tammann's data and have not found a single electrolyte which gives exclusively naked ions. This did not make that total effect any clearer. We had to organize this expedition in the same way, in the footsteps of my former teacher the late Prof. M. de Haas, who always insisted on attempting to arrive at “Knowledge through Measurement” (“door meten tot weten”) and mindful of the words of Debye3) and of Remy2). The results have indeed often surprised us and spurred us to continue.
The specific rotation of lactose
Authors: Ter Horst Maria G. , Wiersma H.
Published: September 2010

The specific rotation of lactose has been estimated for wave‐lengths 5461 and 5893. The influences of concentration, temperature and pH of the solution have been studied and expressed in new formulae.
Reduction of m‐nitrobenzaldehyde
Authors: Gaylord Norman G. , Snyder J. A.
Published: September 2010

The reduction of m‐nitrobenzaldehyde with lithium aluminium hydride gave m,m′‐azobenzyl alcohol rather than the reported m‐aminobenzyl alcohol.
Synthese einiger optisch aktiver α,α′‐Iminosäuren: Untersuchungen in Beziehung zu Eiweissproblemen. I
Authors: Kögl F. , de Flines J.
Published: September 2010

Die vier Stereoisomeren der von Alanin und Asparaginsäure abgeleiteten α,α′‐Imino‐propionsäure‐bernsteinsäure und jene der von Alanin und Glutaminsäure abgeleiteten α,α′‐Imino‐propionsäure‐glutarsäure wurden dargestellt und mit Hilfe eines Kationenaustauschers mit guten Ausbeuten in kristallisierter Form erhalten.

Aus L‐Glutaminsäure‐1,2‐C14‐2,3‐D‐N15 und D‐α‐Brompropionsäure wurde L‐α‐L‐α′‐Imino‐propionsäure‐glutarsäure synthetisiert, die im Glutaminsaure‐Rest mit den drei Isotopen markiert war.
Synthesis, refractometric constants, and some other physical properties of a homologous series of branched alkenes
Authors: Schuhmacher J. P. , Wibaut J. P.
Published: September 2010

The preparation of eleven terms of the homologous series of the 2‐methyl‐1‐alkenes (2‐methyl‐α‐alkenes) is described. The purity of the preparations obtained was determined by measuring the melting curves. The densities and refractive indices of the synthesized compounds at 20° C and 25° C were determined; the measurements of the refractive indices were carried out at nine wave‐lengths. From the values of the densities and the refractive indices the molecular refractions were determined according to the formula of Lorentz‐Lorenz. By the method of the least squares we derived, with the aid of these data, the values of the refraction equivalent of the CH2‐group and the increment of the double bond. The densities and refractive indices determined experimentally appeared to correspond excellently with values calculated from empirical formulae. Besides densities and refractive indices the final melting points, the boiling points and the infra‐red spectra of the synthesized compounds were determined.
Studies on the hill reaction (II)
Authors: Wessels J. S. C. , Havinga E.
Published: September 2010

The influence of the presence of oxygen on the Hill reaction has been investigated by redox potential measurements.

A very simple reaction scheme, implying primary formation of a specific reductant reacting subsequently with the oxidant added, seems to fit kinetical and other data of the reaction.

Some of the results of investigations on the influence of inhibitors and biochemically important substances are reported and discussed; possible causes for the discrepancies in the literature concerned with the action of inhibitors are indicated.
Steric effects on mesomerism: XII). On the effective size of methyl(ene) groups, especially in ortho‐xylene derivatives
Authors: van Helden R. , Verkade P. E. , Wepster B. M.
Published: September 2010

The phenomenon mentioned in an earlier paper,viz.that a methyl group inortho‐xylene derivatives may behave as a larger substituent than the methyl group in comparablepara‐xylene or toluene derivatives, has been investigated more in detail with the aid of deacylation rates, ultra‐violet absorption spectra, molecular refractions, and basic strengths. The phenomenonper sehas been confirmed by this work. Naturally, however, it does not always manifest itself to the same degree; various factors play their part in this respect.

On the strength of the data collected, the order of steric effects of methyl (ene) groups found byArnoldand co‐workers has to be modified as follows: CH2(in o‐xylyl) > CH2(in a 6‐membered ring) > CH2(in tolyl) > CH2(in a 5‐membered ring).
Isomerism in the 2,4‐dinitrophenylhydrazones of α‐keto‐acid esters
Authors: van Duin H.
Published: September 2010

The 2,4‐dinitrophenylhydrazones of α‐keto‐acid esters occur in isomeric forms, here called α‐ and β‐isomers. The α‐isomers differ from the β‐isomers in melting point, UV absorption, and retention volume in partition chromatography. In the presence of hydrogen ions or on irradiation with UV light, these isomers yield equilibrium mixtures in which, at any rate after irradiation, the β‐isomers greatly predominate. The α‐ and β‐isomers of pyruvic esters of homologous normal aliphatic alcohols both form a homologous series, but it is possible to separate not too complicated mixtures of these alcohols from C1 to C18, to identify the individual terms, and to determine their amounts by UV absorption measurements. Finally, some aspects of isomerism in hydrazones and the possible structure of the isolated α‐ and β‐isomers are discussed. For the β‐isomers an extrastabilized syn structure is probable.
Light‐scattering by a number of solvents, in conjunction with data on solutions of Ludox, saccharose‐octa‐acetate, and polystyrene
Authors: Trap H. J. L. , Hermans J. J.
Published: September 2010

A light‐scattering apparatus is described. It is calibrated by means of Ludox solutions, whose absolute turbidities are determined in transmission measurements. A check on the method is made with solutions of sucrose octa‐acetate in methanol and of the international polystyrene sample 2 (2‐1‐49) in butanone and in toluene.

Finally, the turbidities of various solvents are reported, and compared with values quoted from the literature (Sect. 7).
A new method for the preparation of diazomethane
Authors: de Boer TH. J. , Backer H. J.
Published: September 2010

Readily accessible and stable p‐tolylsulphonylmethylnitrosamide C7H7SO2N(NO)CH3 is introduced as an excellent starting material for the synthesis of diazomethane.
Radio‐active exchange studies on the transformations of the hydrates of CaSO4.
Authors: Ketelaar J. A. A. , Heijmann D.
Published: September 2010

The exchange of sulphate ions labelled with sulphur 35 in solution with solid CaSO4 · 2H2O and CaSO4 · 1/2 H2O was studied in saturated solutions at 80° C containing orthophosphoric acid of different concentrations. When the solid phase did not undergo transformation, no appreciable exchange was observed. However, when a transformation into a different modification took place, this was accompanied by total exchange. This indicates that the transformations

magnified image

all take place by the growth of nuclei of the new phase from the solution, thus excluding a zeolithic nature of these phase changes as suggested.
A serial determination of isobutanol in dilute aqueous solutions
Authors: Heertjes P. M. , Steyne P. C. , Talsma H.
Published: September 2010

A combustion method for accurate isobutanol determination in dilute aqeous solutions, to be used for serial determinations, is given.
The effect of surface‐active compounds on the polarographic waves of oxygen and zinc and the electrocapillary curve of mercury
Authors: Bonting Sj. L. , Aussen B. S.
Published: September 2010

The accidental observation of a pronounced shift of the half‐wave potential of oxygen in bacterial media containing small amounts of tween‐80, a surface‐active agent, caused us to investigate the effect of surface‐active agents on the polarographic wave in more detail.

As a result of our studying simultaneously the effects on the electrocapillary curve of mercury, this behaviour could be attributed to the formation of an adsorption layer on the mercury surface. The different effects of different types of surface‐active agents on this curve can be understood from their chemical nature.
Synthesis and physical constants of some 2‐n‐alkylnaphthalenes
Authors: Wibaut J. P. , van Nes K. , Stofberg J.
Published: September 2010

A series of five 2‐n‐alkylnaphthalenes has been synthesized. Several physical properties of these substances have been determined. Their purity has been determined from melting curve data.
Studies on tautomerism III: The nitrosation products of meta‐chlorophenol
Authors: Kraaijeveld A. , Havinga E.
Published: September 2010

As was first reported by Hodgson and his collaborators3) 4), the nitrosation of meta‐chlorophenol gives two products depending on the conditions, the one having a melting point of approx. 142° and the other melting at 184°. The present and the subsequent paper provide experimental evidence showing that of these two “tautomers”, which have been the subject of extensive studies in the past, the low melting compound (m.p. 142°) is an addition complex of equimolecular amounts of the high melting one (3‐chloroquinone‐4‐oxime or 3‐chloro‐4‐nitrosophenol3), m.p. 184°) with 3‐chlorobenzene‐6‐diazo‐oxide (m.p. 124°); the components could be separated and identified by means of chromatography. This conception explains the unorthodox properties of the substance, reported by several authors, e.g. the products of its chemical reactions are derived either from the diazo‐oxide or from the quinone monoxime, the latter reacting according to either of its tautomeric forms5).
Studies on tautomerism IV: The complexes of 3‐halogenobenzene‐6‐diazo‐oxides with quinone monoximes (nitrosophenols) and some other complexes
Authors: Kraaijeveld A. , Havinga E.
Published: September 2010

The nature of the product of m.p. 142°, formed during the nitrosation of meta‐chlorophenol in neutral or weakly acidic medium, has been investigated. The view that it should be considered as a complex compound of equimolecular amounts of 3‐chlorobenzoquinone‐4‐oxime (3‐chloro‐4‐nitrosophenol) and 3‐chlorobenzene‐6‐diazo‐oxide is supported by the analytical data, by its formation from the components, by its behaviour during crystallization and by X‐ray data. Moreover, many discrepancies in the literature find an obvious explanation and there are no longer difficulties such as arise in explaining the chemical behaviour of the substance when regarded as a tautomer of the 3‐chloroquinone‐monoxime (m.p. 184°). One of the possible reactions leading to the formation of the diazo‐oxide is the diazotization of the corresponding nitroso‐compound. The presence of 3‐chlorobenzene‐4‐diazo‐oxide amongst the nitrosation products of meta‐chlorophenol is demonstrated. The nitrosation of m‐bromophenol is shown to give products completely analogous to the chloro‐compounds. Finally, the formation of some characteristic complexes, in which diazo‐oxides take part, are discussed. The conclusion is reached that the 3‐halogeno‐4‐nitrosophenols (3‐halogeno‐benzoquinone‐4‐oximes) now fit in smoothly with the other nitrosophenols.
Additions nucleophiles au bis‐tertiobutylsulfonyl‐acétylène I: (Propriétés du groupe sulfonyle XLI)
Authors: Backer H. J. , Strating J.
Published: September 2010

Le bis‐tertiobutylsulfonyl‐acétylène présente une remarquable tendance à l'addition de réactifs nucléophiles. Les alcools se fixent sans catalyseur et les mercaptannes sont encore plus actifs. Pour les phénols la présence d'un phénolate est de rigueur.
Convenient synthesis of cycloheptanone: (IIIrd communication on sulphonylnitrosamides)
Authors: de Boer Th. J. , Backer H. J.
Published: September 2010

Cyclohexanone and p‐toluenesulphonylmethylnitrosamide yield in a modified Meerwein procedure cycloheptanone (40‐42%).
Δ5‐steroids and provitamins D with branched side chains, I. Synthesis of Δ5‐keto‐steroids
Authors: Louw D. F. , Strating J. , Backer H. J.
Published: September 2010

In order to investigate the influence of the isopropyl group on the antirachitic properties of vitamin D, we synthesised a number of C24 and C22 Δ5‐keto‐steroids with C17 side chains of varying length but all ending in a swallow‐tailed group. As starting materials 3β‐acetoxy‐Δ5‐cholenic acid (I) and the corresponding bisnorcholenic acid (IV) were available. These acids were transformed into their chlorides and made to react with suitable cadmium dialkyls. The latter were prepared from the Grignard reagents and anhydrous CdBr2, which proved much more reactive than CdCl2.