bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Raman spectra of the compounds NaCl. ALCL3 and NOCl. ALCL3
Authors: Gerding H. , Houtgraaf H. 
Published: September 2010

AbstractThe Raman frequency shifts and the depolarization ratio of the Raman lines have been determined for the compounds NaCl. AlCl3 and NOCl. AlCl3 (in the last case with qualitative polarization measurements only). The preparation of pure NOCl. AlCl3 is described in extenso. The properties of the compound finally obtained are different from those given in the literature. NaCl. AlCl3, has to be considered as Na+AlCl4−, and NOCl. AlCl3 as NO+AlCl4−. There is a perceptible interaction between nitrosyl and the chlorines of AlCl4− in the last compound. The properties of NOCl. AlCl3 are intermediate between those for a pure heteropolar compound (NO+AlCl4−) and a pure molecular compound NOCl. AlCl3, being more alike those of the heteropolar form.Force constants have been calculated for AlCl4;−, making use of the Lechner formulae and of those for a Urey‐Bradley field and also of those for the orbital valence force field of Heath and Linnett.
Derivatives of p‐diethoxybenzene: I. 1,4‐diethoxy‐2‐chlorobenzene‐5‐diazoniumborofluoride
Authors: Klaassens K. H. , Schoot C. J. 
Published: September 2010

AbstractThe preparation of 1,4‐diethoxy‐2‐chlorobenzene‐5‐diazoniumborofluoride is described and the structure is proved.
Influence of the solvent on the reactivity of halogeno‐ and alkoxy‐derivatives of nitropyridines towards ammonia
Authors: den Hertog H. J. , Jouwersma C. 
Published: September 2010

AbstractThe reactivity of 2‐bromo‐3‐ethoxy‐6‐nitropyridine, 2‐bromo‐6‐ethoxy‐3‐nitropyridine, 5‐bromo‐2‐nitropyridine, and 3‐ethoxy‐2‐nitropyridine towards solutions of ammonia in water and ethanol has been investigated.It was shown that in these reactions higher polarity of the solvent accelerates all the substitution processes observed. This effect influences the replacement of substituents occupying the para or ortho position towards the nitro‐group rather than that of the other substituents.Applying the effect of the solvent, methods were developed for the synthesis of several derivatives of 2‐ and 3‐aminopyridine, inter alia 2‐amino‐3‐ethoxy‐6‐nitropyridine (an analogon of the 1‐alkoxy‐2‐amino‐4‐nitrobenzenes, the group of sweeting substances studied by Blanksma and Verkade) and two mononitro‐derivatives of 3‐aminopyridine.
Chemical investigation of “Karaffs” (english equivalent, celery, apium graveolens, linn.) seed oil
Authors: Farooq M. O. , Kiamuddin M. , Osman S. M. 
Published: September 2010

AbstractThe fixed oil from the seeds of ‘Karaffs’ has been analysed and its fatty acid composition determined by ester fractionation method. Petroselinic (Δ‐6,7‐octadecenoic) acid has been isolated in colourless shining crystals m.p. 29‐30° and found to be the major component of the fatty acids. The total acids of the oil are composed of resin acids 7% and fatty acids 93% (consisting of palmitic 11.7%, petroselinic 41.1%, oleic 30.5% and linoleic 9.7%).
Kinetics of the formation of methylene linkages in solutions of urea and formaldehyde
Authors: de Jong J. I. , de Jonge J. 
Published: September 2010

AbstractA kinetic investigation is made of the reactions between monomethylol urea, dimethylol urea and urea in acid aqueous solution.Strong indications are obtained that these reactions are all of one type viz. bimolecular hydrogen ion catalyzed reactions between an amidomethylol group and an amide group, leading to the formation of methylene linkages between urea fragments:magnified imageThe rate constant of this reaction appeared to depend on the type of amide group or amidomethylol group that are reacting. The activation energy is about 15 kcal/mole.The reaction between two molecules of dimethylol urea was found to be very slow if occurring at all.The formation of cyclic structures by trimerisation of monomeric methylene urea and the formation of dimethylene ether linkages between urea fragments may be excluded.
Viscous flow through an elastic tube
Authors: Prins W. , Hermans J. J. 
Published: September 2010

AbstractAn approximate theory of viscous flow in elastic capillaries was developed in earlier work2). Because of its biological interest, this theory is compared with the results of model experiments. The wall of the capillary is of rubber; the liquid investigated is a 2.5% Na‐CMC solution in water. Since this liquid is not Newtonian, the theory is extended to non‐Newtonian flow (Sect. 2).It is found that the agreement between theory and experiment is quite satisfactory. The experimental errors are discussed, and an estimate is made of the error involved in the theoretical treatment.
Kinetical experiments on ozonization reactions: V. The ozonization of some norcaradiene derivatives
Authors: Sixma F. L. J. , Detilleux E. 
Published: September 2010

AbstractThe addition of ozone to some norcaradiene derivatives has been studied quantitatively. The reaction of ozone with methyl and ethyl norcaradiene‐7‐carboxylate (I) results in the formation of a diozonide. Ethyl benzonorcaradiene carboxylate (II) forms a monozonide, which subsequently reacts at a much lower reaction rate, probably producing a tetraozonide.These results are in opposition to the hypothesis of Badger, stating that the reactivity of the double bond reagents in norcaradiene derivatives towards “double bond reagents” is greatly reduced by conjugation with the cyclopropane ring.Pure methyl norcaradiene‐7‐carboxylate has been prepared via its dibromo‐derivative.
Derivatives of p‐Diethoxybenzene: II. 1,4‐diethoxy‐2‐aminobenzene‐5‐diazoniumborofluoride
Authors: Klaassens K. H. , Schoot C. J. 
Published: September 2010

AbstractThe preparation of 1,4‐diethoxy‐2‐aminobenzene‐5‐diazoniumborofluoride is described and the structure is proved.
Chloramphenicol analogues I: DL‐2‐dichloroacetamido‐1‐(4‐pyridyl)‐1,3‐propanediol
Authors: van der Meer S. , Kofman H. , Veldstra H. 
Published: September 2010

AbstractThe synthesis of one of the stereoisomeric forms (probably the threo‐form) of DL‐2‐dichloroacetamido‐1‐(4‐pyridyl)‐1,3‐propanediol, the pyridine analogue of chloramphenicol, is described.Its activity against Salm. typhimurium and Ebert. typhi is 1‐3 per cent of that of chloramphenicol only.
On the reaction of Cyclopentadiene with formaldehyde
Authors: Beets M. G. J. , Drukker E. A. 
Published: September 2010

AbstractWhen cyclopentadiene reacts with formaldehyde in the presence of an acid catalyst, an unsaturated m ‐dioxan‐derivative or, under different reaction conditions, an unsaturated diol is formed. Both have been hydrogenated and the properties of the unsaturated and the saturated compounds are described.Some experiments with other unsaturated compounds are reported.
Polarography of some tropolones
Authors: Neish William J. P. , Müller Otto H. 
Published: September 2010

AbstractThe polarographic behaviour of β,γ‐benzotropolone, tropolone, β‐methyltropolone, and β‐methyltropolone methyl ether is described. Certain correlations between these compounds and the naturally occurring tropolones, colchicine and colchiceine, are pointed out. An explanation is offered for discrepancies between the present results for tropolone and data given by James and Speakman 10) for this substance.
Sesquioxydes obtenus par oxydation de thiophenes: (Propriétés du groupe sulfonyle XXXVI
Authors: Melles J. L. , Backer H. J. 
Published: September 2010

AbstractL'oxydation de quelques dérivés simples de thiophène rappelle celle du thiophène lui‐même, en conduisant à des produits ayant la composition de sesquioxydes. Ces produits présentent la formule moléculaire de dimères qui se sont formés par addition diénique entre des sulfones et des sulfoxydes.
Kinetics of the hydroxymethylation of phenols in dilute aqueous solution
Authors: de Jong J. I. , de Jonge J. 
Published: September 2010

AbstractThe hydroxymethylation of phenols has been investigated in the pH range 1‐11 and between 70‐130° C in dilute aqueous solution.The reaction appeared to be bimolecular. Below about pH = 4 the rates were found to be proportional to the concentration of the hydrogen ions, while a proportionality to the concentration of the hydroxyl ions was observed in more alcaline solutions. An influence of the concentration of buffers on the rates has not been observed. The presence of small amounts of triethanolamine does not influence the rate of the reaction. The mechanism of the reaction is discussed.
On the theory of aromatic substitution: II. The orienting effect in some β‐substituted styrene derivatives
Authors: Sixma F. L. J. 
Published: September 2010

AbstractA theoretical discussion is given of the orienting effect of electrophilic substitution in cinnamic acid, cinnamic aldehyde, β‐nitrostyrene, and similar styrene derivatives. The principal formation of ortho‐ and para‐substitution products is in accordance with the theory.
On the theory of aromatic substitution: III. Reactivity in electrophilic and nucleophilic substitution reactions
Authors: Sixma F. L. J. 
Published: September 2010

AbstractThe effect exercised by substituents on the velocity of electrophilic and nucleophilic substitution reactions of benzene derivatives is discussed in the light of a theoretical treatment of the inductive effect2). The theory is checked against the bromination of substituted phenols and the reaction velocity of piperidine with 2‐nitrobromobenzenes substituted in the 4‐position. A linear relationship exists between the logarithm of the reaction velocity and the effect of the substituent on the activation energy of the reaction (as calculated from the theory).
Reaction of hydrogen atoms with elaidic acid
Authors: Boelhouwer C. , van Steenis J. , Waterman H. I. 
Published: September 2010

AbstractThe reaction of elaidic acid with atomic hydrogen at low temperatures (50° C) was investigated. Besides polymerization, a considerable hydrogenation took place; in contrast with catalytic hydrogenation processes no cis‐trans isomerism could be detected, and displacement of the double bond occurred to a small extent only.
Ueber eine synthese des 3,5‐dinitropyridins
Authors: Plažek Edwin 
Published: September 2010

AbstractDas 3,5‐Dinitropyridin wurde auf synthetischem Wege dargestelt, seine Eigenschaften wurden untersucht und einige neue, bisher unbekannte Pyridinderivate als Zwischenprodukte erhalten.
The effect of certain biologically active substances upon photosynthesis and dark CO2 fixation
Authors: Havinga E. , Lynch V. , Norris L. , Calvin M. 
Published: September 2010

AbstractThe influence of certain antibiotics and other biochemically active substances on CO2 fixation in the dark and in the light was studied by C14 tracer techniques. Dinitrophenol stopped both processes, whereas antifolics did not show any influence on the rate or the pattern in CO2 fixation by Scenedesmus obliquus under the conditions of our experiments. Chloromycetin did not alter the velocity of CO2 uptake in the dark or in the light.Penicillin did not alter the total uptake of CO2 but apparently altered the metabolic pattern in dark fixation, e.g. the decrease in the amount of radioactive malic acid formed. In control experiments it was confirmed that malic acid becomes strongly labeled during dark CO2 fixation. Pyrithiamine had no significant influence on total dark fixation, although it lowered the activity of the malic acid spot.Aureomycin hydrochloride had an inhibiting effect on dark fixation in concentrations of about 10−3 M. It accelerated photosynthesis about two times in 3 × 10−5 M concentration and six times in 1.5 × 10−4 M and higher concentrations. Terramycin hydrochloride showed a similar behaviour. Probably part of this effect is due to shifts in pH and another part to increased buffering capacity. While it was possible to eliminate the direct pH effect, it is difficult to estimate the influence of the buffer capacity. Analysis of the chromatograms of the products formed revealed that the activity in most of the products found in short period photosynthesis was increased proportionally. However, addition of aureomycin produced an abnormally high increase in sucrose. Phosphate increased the amount of alanine produced. A short discussion of these phenomena has been given.
The polarographic reduction of conjugated hydrocarbons: II. The reduction of 1,n‐diphenylpolyenes
Authors: Hoijtink G. J. , van Schooten J. 
Published: September 2010

AbstractThe current‐voltage curves of some 1,n‐diphenylpolyenes were measured in a 0.175 molar solution of tetrabutylammoniumiodide in 96% dioxanewater at 25° and 75° C. The experimental half‐wave potentials and the roots a of the M.O. secular equation, corresponding to the lowest non‐occupied π‐electronic level of the conjugated systems, fit the linear equation: ϵ1/2 = a · γ − 1.05 Volts, discussed in part I, giving a mean value of y¯ = − 2.18 ± 0.04 ev (stand, dev.).The theoretical discussion of the course of the reduction of conjugated hydrocarbons has been extended, taking into account the effect of the methylene group on the π‐electronic distribution in the intermediately formed radical ions. From a comparison between the results of these theoretical approximations and the experimental data some reasonable suppositions have been made about the behaviour of these polyenes and their partial reduction products at the dropping mercury electrode during electrolysis.
The preparation of some 1,2,3‐tri(trialkylsiloxy) propanes
Authors: Breederveld H. , Steuns C. H. , Waterman H. I. 
Published: September 2010

AbstractSome 1,2,3‐tri(trialkylsiloxy)propanes have been prepared from the respective trialkylchlorosilanes and glycerol in the presence of pyridine. The specific refractions of these compounds deviate from the theoretical values, as may be expected on the ground of the English theory.
Synthesis of tetrahydroquinoline‐3‐alkyl‐carboxylic acids: Part I. Synthesis of 2‐carboxy‐4‐hydroxy‐3‐quinoline‐alkylcarboxylic acids
Authors: Stefanovic Gjorgje , Čelap Milenko B. 
Published: September 2010

AbstractThe synthesis of 2‐carboxy‐4‐hydroxy‐3‐quinoline‐alkylcarboxylic acids is described, these acids being prepared by the condensation of the triethyl esters of α‐oxalyldicarboxylic acids with aniline. By heating the anils thus obtained, esters are formed which, upon saponification, yield the free acids.
Vinylogie chez les composés de sulfonyle II: (Propriétés du groupe sulfonyle XL)
Authors: Backer H. J. , Strating J. , Hazenberg J. F. A. 
Published: September 2010

AbstractPoursuivant leurs recherches sur les composes sulfones vinylogues, les auteurs ont fait réagir le 1,2‐dichloro‐1‐tertiobutylsulfonyl‐éthène (I) avec l'ammoniac, plusieurs amines primaires et secondaires; quelques composés à méthylène actif et avec des magnésiens.Enfin on a soumis le sulfochlorure vinylogue (I) à une réduction, qui conduit à plusieurs produits.
Die Absorptionsgeschwindigkeit von Ammoniak in Wasser bei vorhandensein von Kohlendioxyd: Ein Beitrag zur Berechnung von Ammoniakwäschern in Gaswerken
Authors: Bramslev E. 
Published: September 2010

AbstractDie für Gaswerke so wichtige gleichzeitige Auswaschung von Ammoniak und Kohlendioxyd wird als ein Diffusionsprozess in Verbindung mit einer chemischen Reaktion behandelt.Die aufgestellten Differentialgleichungen werden unter Vernachlässigung von Gliedern weniger Bedeutung integriert und, es wird gezeigt, wie das Resultat für einen Satz gegebener Werte mit einer numerischen Integration in guter Übereinstimmung ist.Die Absorption von Kohlendioxyd in Ammoniakwasser wird nach derselben Methode behandelt und die Resultate stimmen hier mit van Krevelen5) überein.In einem mit 5 mm Raschigringen gefüllten Glasturm werden Absorptions‐versuche mit Gas mit wechselndem Ammoniak‐ und Kohlendioxydgehalt ausgeführt, und die Resultate sind mit den entwickelten Formeln in guter Übereinstimmung.
Migration of halogen atoms in halogeno‐derivatives of 2,4‐dihydroxypyridine (II)
Authors: Kolder C. R. , den Hertog H. J. 
Published: September 2010

AbstractWhen 3‐bromo‐2,4‐dihydroxypyridine is heated with an aqueous solution of nitric acid, 5‐bromo‐2,4‐dihydroxy‐3‐nitropyridine is formed. This reaction product was also obtained by nitrating 5‐bromo‐2,4‐dihydroxypyridine and by brominating 2,4‐dihydroxy‐3‐nitropyridine; its structure was established by converting it into the known 5‐bromo‐2,3,4‐trichloropyridine.The mechanism of the nitration of 3‐bromo‐2,4‐dihydroxypyridine is discussed in comparison with that of its chlorination.
The polarographic reduction of conjugated hydrocarbons: III. Comparison of various M.O. approximations with experimental half‐wave potentials of alternant hydrocarbons
Authors: Hoijtink G. J. , van Schooten J. 
Published: September 2010

AbstractThe linear relation ϵ = a. γ −1.05 Volts1a) has been discussed, using for the computation a the following M.O. approximations:a) the original method of Hückel;b) the approximation used by Wheland (overlap integral 1/4);c) the non‐bonding M.O. method of Longuet‐Higgins.Substituting in the linear equation the half‐wave potentials of twenty alternant hydrocarbons and the computed roots a, the following mean values of the resonance parameter γ were obtained:magnified imageSome conclusions have been drawn about the applicability of these semiempirical methods.
Thorium ‐ its estimation and separation from cerite earths: Use of 7‐hydroxy coumarin‐4‐acetic acid
Authors: Eswaranarayana N. 
Published: September 2010

Abstract7‐Hydroxy coumarin‐4‐acetic acid precipitates thorium completely in the pH range 2.5 to 3.2. The precipitate is crystalline and may be filtered easily. Thorium in monazite is estimated after a single precipitation. As little as 1 mg of thorium is accurately estimated. The metal is further separated from twice its amount of uranium in a single precipitation. Most of the common elements do not interfere.
The chemical composition of some condensates of urea and formaldehyde
Authors: de Jong J. I. , de Jonge J. 
Published: September 2010

AbstractSome condensates of urea and formaldehyde were prepared from solutions of pH 2‐7 at temperatures of 20‐76° C. These products have been analysed with respect to their content of methylene groups, methylol groups and urea groups. The average molecular weights could be estimated. The analytical data are in harmony with the occurrence of methylene bridges between the urea fragments. The condensates will be formed by a stepwise condensation reaction.“Methylene urea” may be a mixture of condensates with an average molecular weight of 300‐500.
Steric hindrance in the para‐nitroanilides of 2,3‐ and 2,5‐dimethylbenzoic acid
Authors: Soei Ng Tet , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractThe deacylation rate constants of the compounds mentioned in the title provide corroborative evidence for the existence of the “ortho‐xylene effect”.
Copolymerization of drying oils
Authors: Boelhouwer C. , Tien Liem Tjing , Waterman H. I. 
Published: September 2010

AbstractUnsaturated hydrocarbons were prepared from methyl esters of stearic, oleic, linoleic, and linolenic acid, and from linseed oil fatty acid methyl esters, by replacing the ester group by an alkene group (reaction of the esters with alkyl magnesium halide and dehydration of the tertiary alcohols formed).These olefins show the same polymerization phenomena as do the esters from which they are derived. Thermal polymerization of olefins derived from methyl linoleate and methyl linolenate leads to monocyclic and bicyclic dimers, respectively, in accordance with the results of polymerization of the corresponding esters.Copolymerization of tung oil with olefins prepared from linseed oil fatty acid esters only occurs at higher temperatures (275° C); the reaction is promoted by sulphur dioxide. Copolymerization of tung oil and linseed oil is therefore unlikely at temperatures below 250° C.Copolymerization of oleic and elaidic esters with olefins derived from linoleic acid esters does not occur at 300° C; this makes it probable that mono‐unsaturated acids, when present in drying oil glycerides, do not participate in the polymerization.
Empêchement stérique dans la réaction des amines sur les quinones halogénées
Authors: Buu‐Hoï Ng. Ph. , Royer René , Hubert‐Habart Michel 
Published: September 2010

AbstractIl est montré que la réaction entre les amines et les quinones halogénées telles que la 2,3‐dichloro‐l,4‐naphtoquinone et la chloranile est très sensible à l'empêchement stérique: plusieurs amines aromatiques encombrées en position ortho n'ont pas réagi dans les conditions expérimentales habituelles avec ces deux quinones.
The synthesis of thiazole‐2‐ and of thiazole‐5‐ carboxylic acid via a halogen‐metal exchange reaction)
Authors: Beyerman H. C. , Berben P. H. , Bontekoe J. S. 
Published: September 2010

AbstractTwo syntheses of the hitherto unknown 5‐bromothiazole are described. 2‐Bromothiazole and 5‐bromothiazole could be converted via the corresponding thiazolyllithium compounds into thiazole‐2‐ and thiazole‐5‐carboxylic acid respectively. This constitutes a new convenient synthesis of these acids, which up to now were rather difficultly accessible.
A two‐circle optical goniometer, specially adapted to measuring small crystals of organic compounds
Authors: Perdok W. G. , Terpstra P. 
Published: September 2010

AbstractAfter a historical review of the development of goniometers for crystal measurements, a description is given of an improved, modernized construction.It is emphasized that the instrument in its present form can be used for routine measurements without difficulty by any chemist with a minimum of crystallographic knowledge.
Aconic acid and related compounds: I. Discussion of the structure of aconic acid
Authors: Rekker R. F. , Brombacher P. J. , Hamann H. , Nauta W. Th. 
Published: September 2010

AbstractTo aconic acid, first described in literature by Kekulé, the structure of a β,γ‐butenolide was given by Fittig and Beer. In 1947 Campbell and Hunt put forward arguments for an α,β‐butenolide structure. These arguments were based on a new synthesis of the acid and a comparison of the U.V. absorption spectrum of aconic acid with those of mesaconic acid and itaconic acid. Close inspection of the properties of aconic acid shows however that Campbell and Hunt's synthesis of aconic acid is not proving for its structure.Moreover these authors drew their spectral conclusions only from curveshapes, so we found it necessary to repeat the U.V. measurements at lower wave lengths. The rightness of the structure proposed by Campbell and Hunt could be proved.
On the ozonization and the ozonolysis of naphthalene, 2,3‐dimethylnaphthalene, and 1,4‐dimethylnaphthalene in connection with the reactivity of the ring system
Authors: Kampschmidt L. W. F. , Wibaut J. P. 
Published: September 2010

AbstractFrom a kinetic investigation of the action of ozone on naphthalene and 2,3‐dimethylnaphthalene it appears that in both cases two molecules of ozone are rapidly taken up; the diozonide formed continues to react very slowly with ozone.From the compounds formed upon ozonolysis of 2,3‐dimethylnaphthalene it follows that upon the action of ozone on 2,3‐dimethylnaphthalene two isomeric diozonides are formed; in one diozonide (main product) the O3 groups are bound in the methylated six‐membered ring, the other diozonide (by‐product) contains the O3 groups in the non‐methylated six‐membered ring.On the strength of theoretical considerations and kinetic investigations of the ozonization reaction, a reaction mechanism is framed according to which the first molecule of ozone adds on to an α‐β bond of the ring system. From the reaction mechanism framed it is inferred what aliphatic and aromatic decomposition products may be formed in the ozonolysis of naphthalene and of 2,3‐dimethylnaphthalene. The decomposition products to be expected have all been found and identified. From the aromatic and aliphatic decomposition products formed in the ozonolysis of 1,4‐dimethylnaphthalene it follows that also upon the action of ozone on this naphthalene homologue a molecule of ozone primarily adds on to an α‐β bond.