bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses of polychloro‐compounds with aluminium chloride XI: The reaction between carbon tetrachloride and 1,2‐dichloroethene
Authors: Prins H. J. 
Published: September 2010

AbstractThe course of this reaction depends largely upon the degree of dehydrohalogenation of the reaction products and upon the concentration of the 1,2‐dichloroethene. It is shown that by suitable variation of the experimental conditions the reaction can be used for the preparation of 1,1,2,3,4,5,5‐heptachloropentene‐1, a new compound C6Cl8, m.p. 94°, and the already known isomeric compound, m.p. 183°. The first mentioned isomer can be easily transformed into the latter.A novel feature is the formation of small amounts of hexachlorocyclopentadiene, the origin of which is discussed. It is further shown that 1,1,2,3,4,5,5‐heptachloropentene‐1 reacts with 1,2‐dichloroethene to form the expected nonochloroheptene [1,1,2,4,5,5‐hexachloro‐3(1′,2′,2′‐trichloroethyl)‐pentene‐1].
2‐Methyl‐4‐phenylfuran and 1‐phenylcyclopenten‐1‐one‐3
Authors: Morel Th , Verkade P. E. 
Published: September 2010

AbstractThe substance described by Buchner and Schröder 3) as being 2‐methyl‐4‐phenylfuran has been proved to be 1‐phenylcyclopenten‐1‐one‐3.
The directive influence of the n‐oxide group during the nitration of derivatives of pyridine‐n‐oxide (II)
Authors: den Hertog H. J. , Henkens C. H. , Dilz K. 
Published: September 2010

Abstract3,5‐Dibromopyridine‐N‐oxide, when heated with a mixture of fuming nitric acid and sulphuric acid, just like 3‐bromo‐ and 3‐ethoxypyridine‐N‐oxide, yields the 4‐nitro‐derivative. In 3,5‐diethoxypyridine‐N‐oxide, however, the nitro‐group enters the 2‐position.3,5‐Dibromo‐4‐nitropyridine‐N‐oxide and 3,5‐diethoxy‐2‐nitropyridine‐N‐oxide are found to be phototropic substances.
The reactivities of alpha methylenic groups towards free radicals: II. Steric effects in alkylbenzenes
Authors: Kooyman E. C. , Strang A. 
Published: September 2010

AbstractThe retardation method 1) described previously has been applied to a number of polyalkylbenzenes. The reactivities of the alpha methylenic *) groups towards hydrogen abstraction by trichloromethyl radicals were compared with those of monoalkylbenzenes.Compounds having two alkyl groups in adjacent positions ‐ with the exception of methylated benzenes ‐ were found to be far less reactive than expected on the basis of additivity. In these cases, scale drawings as well as model considerations show that coplanarity of the three remaining valencies at the alpha methylenic carbon atom is markedly interfered with by steric repulsions. With other isomers, reactivity appeared to be nearly additive.The results are interpreted in terms of steric hindrance of resonance: geometrical arguments are put forward to show that this hindrance occurs not only in the final state — i.e. in the benzyl‐type radical formed upon hydrogen abstraction ‐ but also in the transition state.The extremely low reactivity found for the anthracene‐maleic anhydride addition product is attributed to the fact that the bridge prevents formation of a planar radical.
Syntheses with the aid of γ‐picolyllithium I: Preparation of 4‐alkylpyridines
Authors: Wibaut J. P. , Hey J. W. 
Published: September 2010

AbstractIf phenyllithium in an ethereal solution is slowly added to an ethereal solution of the equivalent amount of 4‐methylpyridine, and an equivalent amount of an alkyl bromide is subsequently allowed to act on it, a 4‐alkylpyridine is formed as the main product of the reaction. In this way we prepared the 4‐n‐alkylpyridines, in which the alkyl group contains 3‐10 carbon atoms. The yields amount to at least 60% of the theory, calculated on lithium. By the action of phenyllithium on 4‐ethylpyridine, followed by the action of n‐butyl bromide, we obtained a 30% yield of the 4‐(hexyl‐2′)‐pyridine or 2‐(pyridyl‐4′)‐hexane.
Syntheses of polychloro‐compounds with aluminium chloride XII: The condensation of formaldehyde, chloromethyl methyl ether and of symm. dichlorodimethyl ether with 1,2‐dichloroethene
Authors: Prins H. J. 
Published: September 2010

AbstractThe present paper describes the formation of the di‐ether of 2,3,3‐trichloropropanol‐1 (2,3,3,2′,3′,3′‐hexachloro‐di‐n‐propyl ether) by the condensation of paraformaldehyde with 1,2‐dichloroethene and of the same ether together with 2,3,3‐trichloropropanol‐1 when trioxane is used as the source of formaldehyde.The same ether is also obtained by condensing symm.‐dichlorodimethyl ether with 1,2‐dichloroethene. The condensation of chloromethyl ether with 1,2‐dichloroethene gives the methyl ether of 2,3,3‐trichloropropanol‐1.The mechanism of these reactions is discussed.
Analogues de la ρ‐hydroxypropiophenone dans la serie du biphenyle
Authors: Hoï Buu‐ , Xuong N. D. , van Thang K. 
Published: September 2010

AbstractOn décrit dans ce travail une série de cétones dérivées du 4‐hydroxy‐biphényle ayant une constitution analogue à celle de la ρ‐hydroxypropiophénone, et pouvant ainsi présenter un intérét biologique; quelques dérivés hétérocycliques de ces cétones ont également été synthétisés.
Cyclic oligomers of caprolactam: (An unusual case of stereo isomerism in higher‐membered rings)
Authors: Hermans P. H. 
Published: September 2010

AbstractThe low‐molecular substances other than caprolactam, present in hot water extracts of caprolactam polymerisates with an average DP of about 150, are investigated.Using the guidance of X‐ray powder spectra of high resolution, three individual compounds have been isolated which together constitute the entire substance (or almost so). None of these compounds contains free COOH or NH2 groups, and their elementary composition is identical with that of caprolactam. They obviously represent cyclic oligomers of the lactam.According to the molecular weight determinations in phenol, two of these compounds (m.p. 348° and 248°) are cyclic dimers and one (m.p. 242°) is a cyclic trimer. The first two, designated as the α‐ and β‐dimer, seem to represent stereo‐isomerides of the 14‐membered diamide ring system. The possible nature of this unexpected isomerism is briefly discussed.Some properties and the X‐ray powder spectra of these compounds, together with those of some linear oligomers of ϵ‐aminocaproic acid synthesized by van der Want, are described.
Calculations of the heat of adsorption of hydrogen on platinum
Authors: Sachtler W. M. H. 
Published: September 2010

AbstractThe results of recent measurements on the work functions of a pure and a hydrogen‐covered platinum surface are used to calculate the heat of adsorption of hydrogen on platinum. The value obtained is compared with experimental results and with another theoretical value, calculated from Beeck's velocity constant, for the hydrogenation of ethylene on platinum by using a general relation between velocity constant and heat of adsorption as given by Beeck.
The binary system of selenium tetrachloride with aluminium chloride and of tellurium tetrachloride with aluminium chloride
Authors: Houtgraaf H. , Rang H. J. , Vollbracht L. 
Published: September 2010

AbstractThe binary freezing‐point diagrams of SeCl4AlCl3 and TeCl4AlCl3 were determined. Both systems show a dissociating compound in a molecular ratio 1: 1 with melting points of 163.8° C resp. 149.3° C.In the case of the binary system SeCl4AlCl3 only one half of the system, with AlCl3 in excess, could be determined because of the decomposition of SeCl4 at higher temperatures. The compound TeCl4 · AlCl3 could be distilled in high‐vacuum without decomposition.An approximate value for the heat of fusion of both addition compounds was calculated.
A new synthesis of aryl‐aliphatic alcohols: VI. Application of the method to 4‐styryl‐m‐dioxane
Authors: Drukker E. A. , Beets M. G. J. 
Published: September 2010

AbstractBy application of the method, described in the previous papers of this series2), to trans‐4‐styryl‐m‐dioxane, a mixture of 5‐phenyl‐penten‐4‐ol‐1 and 5‐phenyl‐pentanol is obtained in good yield. 4‐Phenylethyl‐m‐dioxane does not react under the same conditions.
Electrochemical behaviour of ion‐exchanging substances: VII. Characterization of the root substance by a continuous range of titration constants
Authors: MacGillavry D. , Tendeloo H. J. C. 
Published: September 2010

AbstractFor the interpretation of potentials of plant roots in electrolyte solutions it is desirable to know the variations with pH of net charge on the non‐permeating material inside the root wall. Since this is a very complex mixture, it is proposed to use as a model a solution characterized by a continuous range of titration constants.
The synthesis of compounds structurally related to isonicotinic acid hydrazide
Authors: Beyerman H. C. , Bontekoe J. S. , van der Burg W. J. , Veer W. L. C. 
Published: September 2010

AbstractThe synthesis is described of a number of 1‐ and 4‐substituted derivatives of pyridine related to isonicotinic acid hydrazide (INH) and of isonicotinoyl hydrazones of some aldehydes. These compounds were prepared in order to test them for possible growth‐inhibiting properties against Mycobact. tuberculosis.
Structure of α.ω‐diphenylpolyenes: II. Crystal structure of the monoclinic and orthorhombic modification of 1,10‐diphenyl‐1,3,5,7,9‐decapentaene
Authors: Drenth W. , Wiebenga E. H. 
Published: September 2010

Abstract1,10‐Diphenyl‐l,3,5,7,9‐decapentaene crystallizes in a monoclinic and in an orthorhombic modification. Both structures have been determined by means of [010] and [100] Fourier projections. The value of the disagreement factor R ranges from 0.14 to 0.21 for the different modifications and projections; the standard deviations in the bond lengths are 0.03‐0.04 Å. In both modifications the conjugated chain of the molecule shows the all trans configuration; there exists, however, a small but significant difference between the general shapes of the molecules in the two structures. The atomic distances are compared with theoretical values, calculated by the method of molecular orbitals.
Polar effects in some atomic chlorinations
Authors: van Helden R. , Kooyman E. C. 
Published: September 2010

AbstractThe side‐chain chlorination of substituted toluenes as well as the atomic chlorination of some aliphatics t‐butyl‐X were investigated, using sulphuryl chloride as the chlorinating agent.In both cases marked polar effects were observed. As in previous experiments with other strongly electronegative free radicals electronattracting groups cause a decrease in reactivity whereas electron‐repelling groups facilitate hydrogen removal.
Hofmann rearrangement of diphenylacetamide & ββ‐diphenylpropionamide. Schiff's base as a new by‐product of the Hofmann reaction. Benzhydryl‐amine from diphenylacethydroxamic acid
Authors: Rahman Aziz‐Ur , Farooq M. O. 
Published: September 2010

AbstractIn view of the lack of any systematic work already mentioned in the literature on the Hofmann reaction with amides containing two or more simple aryl groups in α‐ or β‐position, work was taken up on the Hofmann rearrangement of diphenylacetamide and ββ‐diphenylpropionamide, to serve as examples of αα‐ and ββ‐arylaliphatic amide respectively. Results indicated that while no special difficulty was encountered with ββ‐diphenylpropionamide, diphenylacetamide could be converted to the corresponding amine only in a more concentrated alkali solution than is customarily employed.Experiments carried out to ascertain the optimum conditions for the successful Hofmann rearrangement of diphenylacetamide yielded, in dilute alkali solution, a new secondary reaction product – a Schiff's base, viz. N‐benzhydryl‐benzophenone‐imine, instead of the expected benzhydryl‐amine. A theoretical explanation has been submitted in support of this abnormal observation.Benzhydrylamine has also been obtained through the Lossen rearrangement of N‐benzoyl‐diphenylacethydroxamic acid in about 20% yield; a by‐product, viz. N‐Nî‐dibenzhydryl‐urea, was isolated in 52% yield.
On the interpretation of the conductivity of soap solutions
Authors: Stigter D. 
Published: September 2010

AbstractIt is shown that measurement of the conductivity of micellar solutions provides a rather sensitive test regarding the size distribution of the micelles. In a number of systems the micelles are found to be practically uniform. In this case information on the equivalent conductance of the micellar soap can be obtained from the conductivity data in the range above the cmc. The data in the transition range (around the cmc) can be interpreted with the help of the law of massaction and lead to the molecular weight of the micelles.Anomalous conductivity curves with a maximum slope just above the cmc are interpreted in terms of a wide size distribution of the micelles.
Simplified isolation of the non‐saponifiable matter in the analysis of oils
Authors: Mulder F. J. 
Published: September 2010

AbstractA simplified method is given for the analytical isolation of non‐saponifiable matter from oils.After saponification in alcohol the alcoholic soap solution is completely dissolved in a measured quantity of benzene and the benzene solution is washed with water. The concentration in the benzene solution is determined after drying. By this method the tedious operations of extraction and quantitative transfer of the extracts are avoided.This method is suitable for the determination of the vitamins A and D.
Thermal rearrangement of sulphonylmethylnitrosamides (IVth communication on sulphonylnitrosamides)
Authors: de Boer Th. J. 
Published: September 2010

AbstractSulphonylnitrosamides, ArSO2N(NO)R, when heated in inert solvents, undergo first order decomposition into nitrogen and alkyl arylsulphonates (ArSO3R). A mechanism involving an intermediate diazosulphonate (ArSO2ONNR) is proposed.
Addition reactions of imenes
Authors: Dijkstra R. , Backer H. J. 
Published: September 2010

AbstractImenes most readily add amines and other nucleophilic reagents, such as water, alcohols, mercaptans, hydrogen sulphide, hydrocyanic acid. Bis‐methylsulphonyl‐N‐methylimene, which was studied more extensively, proved to possess not only electrophilic but also nucleophilic properties. Thus it adds HCl and can be applied in the Friedel‐Crafts reaction.
Ozone absorption and ozonolysis of cyclooctatetraene
Authors: Wibaut J. P. , Sixma F. L. J. 
Published: September 2010

AbstractAt −31° cyclooctatetraene absorbs 3.5 moles of ozone. Among the products of the ozonolysis of cyclooctatetraene, ethane‐1,1,2,2‐tetracarboxylic acid and succinic acid were found. The results may be interpreted either in terms of an equilibrium between cyclooctatetraene and bicyclo‐(4.2.0)‐octatriene or in terms of a reaction mechanism analogous to the one postulated by Friess and Boekelheide 10) for halogen addition.
Amperometrischer Nachweis von Ionen in Papierchromatogrammen
Authors: de Vries G. , van Dalen E. 
Published: September 2010

AbstractDie Chloride und Perchlorate der Alkalimetalle lassen sich papierchromatografisch gut trennen, ihr Nachweis ist aber schwierig. Es wird ein Apparat beschrieben, mit dem die Ionen auf Grund des Stromdurchganges durch die Flecken gefunden werden. Der optimale Spannungsbereich sowie die Empfindlichkeit der Methode werden für die Ionen von Li, Na und K, einzeln und nebeneinander, erörtert.
On the determination of hydroperoxides
Authors: Wibaut J. P. , van Leeuwen H. B. , van der Wal B. 
Published: September 2010

AbstractAn improved iodometric procedure for the determination of hydroperoxides is described. Theoretical values are obtained for seven structurally different compounds. The estimation of 1‐tetralyl hydroperoxide is affected by the presence of α‐tetralone if the determination is carried out at too high a temperature.
On the theory of adsorption chromatography for liquid mixtures
Authors: Baylé G. G. , Klinkenberg A. 
Published: September 2010

AbstractThe theory of adsorption chromatography for liquid multicomponent mixtures is critically reviewed and it is shown to what limitations the introduction of a number of assumptions leads.As regards the shape of chromatograms in development chromatography with two solutes, it is proved that both the discontinuous shape (Glueckauf) and the continuous one (Offord and Weiss) are consistent with the equilibrium theory, the shape to be found in a specific case depending on the mathematical characteristics of the adsorption isotherms that govern the process.The most important check on theory will be to verify in what cases the relation, according to which all concentrations belonging to a given set move at equal velocity through a column, is valid.
The influence of caffeine on the coupling reaction between β‐naphthol and p‐diazobenzenesulphonic acid
Authors: Overbeek J. Th. G. , Vink C. L. J. , Deenstra H. 
Published: September 2010

AbstractThe rate of the coupling reaction between β‐naphthol and p‐diazobenzenesulphonic acid is lowered by addition of caffeine. This effect can be explained by complex formation between caffeine and the two reactants. The complex between caffeine and β‐naphthol is of the 1‐1 type; that between caffeine and p‐diazobenzenesulphonic acid probably also. Complexity constants have been determined. In the presence of caffeine the reaction follows two (or three) separate paths, one involving an activated complex consisting of one β‐naphtholate ion and one diazonium ion, and one (or two) involving an activated complex consisting of one molecule of each of the reactants and one molecule of caffeine. Rate constants have been determined at 20° C, using a colorimetric technique.
The reactivity of alpha‐methylenic groups towards free radicals: V. Azo‐compounds and ketazines
Authors: Kooyman E. C. 
Published: September 2010

AbstractThe reactivity of alpha‐methylenic groups in azo‐compounds and in ketazines has been investigated both theoretically and experimentally.The results of molecular orbital calculations suggest that both groups of compounds are more reactive than olefins or alkylbenzenes. Reactivity measurements using the retardation method described previously lead to the same conclusion.
Steric effects on mesomerism: XIV. The basic strength of dibenzoquinuclidine and its bearing on the basic strength and the mesomeric energy of aromatic amines
Authors: van der Krogt S. M. H. , Wepster B. M. 
Published: September 2010

AbstractThe basic strength of dibenzoquinuclidine (III) is found to be about 3 pKa units lower than that of benzoquinuclidine (II). This corroborates an earlier conclusion that the inductive effect of a phenyl group introduced on the nitrogen atom of an amine, brings about a decrease of the basic strength of this magnitude.Ultra‐violet spectra and the coupling (in) ability are discussed.
The preparation of non‐substituted amidrazones
Authors: van der Burg W. J. 
Published: September 2010

AbstractThe synthesis of a number of non‐substituted amidrazones is described. The compounds were prepared in order to test them for possible growth‐inhibiting properties against Mycobacterium tuberculosis. They were characterised by their N1‐benzylidene derivatives and some of them by their conversion into tetrazoles.
Production and physical properties of radioisotopes
Authors: Bakker C. J. 
Published: September 2010

AbstractThe production of radioisotopes in nuclear reactors and in cyclotrons is discussed. The types of nuclear reactions involved are mentioned. As to the production of radioisotopes, the cyclotron is an important complement to the nuclear reactor. Examples of disintegration schemes of radioisotopes are given. The loss of energy of β‐ or γ‐rays during their passage through matter is briefly discussed. The precautions necessary when working with radioisotopes are mentioned shortly.
Use of I131‐labelled substrates in the estimation of proteolytic and lipolytic enzymes
Authors: Brante G. 
Published: September 2010

AbstractWhen I131‐labelled protein or fat is used as a substrate for proteolytic or lipolytic enzymes, respectively, unsplit substrate as well as split products are readily evaluated quantitatively by measurement of their radioactivity. The application of such substrates in the clinical estimation of enzyme activities has been tried by the author.
Total‐body γ‐radiation from patients with internally deposited thorium
Authors: Rundo J. , Faber Mogens 
Published: September 2010

AbstractThe application of a total‐body γ‐monitor using high‐pressure ionisation chambers to the measurement of radiation from patients is described. Patients with internally deposited thorium have been studied. The interpretation of the measurements in relation to the amount of thorium present, the age of the deposits, the accumulation of daughter products and the distribution of the thorium in the body is discussed.
Über die Anwendung der optischen Testmethoden Warburgs zur Untersuchung von Stoffwechselproblemen in der Klinik
Authors: Englhardt‐Goelkel A. , Prosiegel R. , Seitz W. , Stuhlfauth K. 
Published: September 2010

AbstractDie Verfasser berichten über die Anwendung fermentativer Testmethoden zur Durchführung von Stoffwechseluntersuchungen in der Klinik. Diese Methoden beruhen auf dem Prinzip der Messung der Lichtabsorption des hydrierten DPN, das als Coferment am Ablauf vieler enzymatischer Reaktionen beteiligt ist. Alpha‐Ketoglutarsäure wurde mit Glutaminsäureoxydase, Brenztraubensäure mit Milchsäuredehydrase, beide nach Zusatz von DPNH, getestet. Die Ergebnisse zeigten, dass der alpha‐Ketoglutarsäurespiegel bei Gesunden im Mittel 0.17 mg% beträgt. Ersteigt deutlich im Fieber und nach peroralen und intravenösen Glutaminsäuregaben. Der Gipfel der alpha‐Ketoglutarsäurekurve nach Gluatminsäurebelastung liegt bei Leberkranken deutlich höher als bei Gesunden. Brenztraubensäure steigt besonders nach Fruktose‐ und Glukosegaben, und zwar nach Fruktose rascher und höher als nach Glukose.Ausserdem wurden Messungen von Enzymaktivitäten in laparoskopisch gewonnenen Gewebsstücken aus menschlichen Lebern durchgeführt. Es wurden 5 Enzymssyteme getestet, an deren Reaktionen ebenfalls DPN als Coferment beteiligt ist: Aldolase, Triosephosphatdehydrase, Milchsäuredehydrase, Glutaminsäuredehydrase und Cytochrom‐C‐Reduktase. Nach Behandlung mit Leberextrakten war die Aktivität sämtlicher Enzymsysteme gesteigert.
Potentiometrische Chloridbestimmung im Blutserum, liquor cerebrospinalis und im Urin
Authors: Rosenmund H. 
Published: September 2010

AbstractEs wird über eigene Erfahrungen mit der potentiometrischen Chloridbestimmung in Körperflüssigkeiten berichtet. Die Bestimmung beruht auf der direkten argentometrischen Titration der Chlorionen im nativen Untersuchungsmaterial. Das potentiometrische Verfahren ist genauer und rationeller als die gewöhnlichen Titrationsmethoden, es wird zur allgemeinen Anwendung in der klinisch‐chemischen Analyse empfohlen.
The infrared spectra of some alkoxytrichlorosilanes
Authors: Stuart A. A. Verrijn , la Lau C. , Breederveld H. 
Published: September 2010

AbstractThe infrared spectra of methoxy‐, ethoxy‐, n‐propoxy‐, isopropoxy‐, cyclopentoxy‐, and cyclohexoxytrichlorosilane, and of methoxy cyclopentane have been measured. An interpretation is given, in which the attention is especially focussed on the skeletal stretching vibrations involving the SiO, C‐O and C‐C bonds.
Studies on vitamin D and related compounds II: Preliminary communication on the interconversion and the possible cis/trans isomerism of previtamin D and tachysterol
Authors: Koevoet A. L. , Verloop A. , Havinga E. 
Published: September 2010

AbstractStarting from the hypothesis that previtamin D and tachysterol may be cis/trans isomers, it has been found that previtamin D in solution readily transforms into tachysterol under the influence of small amounts of J2.