bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dosage Rapide de L'Aluminium dans les Alliages Cuivreux
Authors: Detmar D. A. , van Aller H. C. 
Published: September 2010

AbstractUn mode opératoire pour le dosage gravimétrique de l'aluminium applicable ã tous les alliages cuivreux dont la teneur en aluminium est supérieure ou égale à 0.5 %, est décrit.L'aluminium est précipité par la 8‐hydroxyquinoléine dans une solution ammoniacale, contenant du cyanure de potassium, de l'acide tartrique et du complexone‐III.Les éléments, qui se trouvent normalement dans ces alliages, c.à.d. Cu, Zn, Sn, Fe, Mn, Pb, Ni et Co ne gênent pas et ne sont pas séparés.
The sterical structure of tropinol and pseudo‐tropinol
Authors: Beyerman H. C. , Siegmann C. M. , Sixma F. L. J. , Wisse J. H. 
Published: September 2010

AbstractIn a preliminary communication F. L. J. Sixma, C. M. Siegmann and H. C. Beyerman, Proc. Koninkl. Nederl. Akad. Wetenschap. B 54, 452 (1951).
some of us have reported on the rates of alkaline hydrolysis of the benzoic and p‐nitrobenzoic esters of tropinol and ψ‐tropinol and of their methiodides in aqueous ethanol.It is shown in the present investigation, that in the afore‐mentioned solvent mixture a rapid trans‐esterification of the methiodides takes place. This caused the assignment of wrong structures to tropinol and ψ‐tropinol.Our measurements have been repeated therefore in aqueous dioxan. The reaction rates are now in complete accordance with the expectations based on the configurations and conformations deduced for the tropane alkaloids by other means.
Chemistry of acetylenic ethers. XXIII. Some reactions of acetylenic thioethers
Authors: Arens J. F. , Volger H. C. , Doornbos T. , Bonnema J. , Greidanus J. W. , van den Hende J. H. 
Published: September 2010

AbstractFrom acetylenic thioethers, Grignard or lithium derivatives can be obtained, which react with carbonyl compounds to yield the expected carbinols. The reactions with carbon dioxide and ethyl chlorocarbonate also are normal. By oxidative “dimerisations” of the thioethers the diacetylenic bis‐thioethers are obtained. Hydration of acetylenic thioethers is much less easy then for oxygen ethers. Piperidine is added in an anti‐Markownikow way as is also the case for thiols and thiol acids.Rearrangement of carbinols derived from acetylenic thioethers by acids yields the expected thiol esters. This is a method for the preparation of α,β‐unsaturated thioesters.Partial reduction of the carbinols and hydrolysis of the products yields α,β‐unsaturated aldehydes.
Phenoxyacetic acid
Authors: van Essen H. , Beets M. G. J. 
Published: September 2010

AbstractIn a recent paper by Brettle a synthesis of phenoxyacetic acid in two steps giving an overall yield of 56% of the theoretical is recorded.This method is described as a favorable alternative for the single step process because, as the author of the above mentioned paper observes “the condensation of phenol and chloroacetic acid in aqueous alkali gave poor yields of phenoxyacetic acid”.Several years ago, however, we developed a process which gives reproducible yields of about 82% in one step. As the literature gives little information on the single step process, we describe our method in some detail.
Investigations on agricultural fungicides. I. Trichloromethyl thiolsulphonates
Authors: Uhlenbroek J. H. , Koopmans M. J. , Huisman H. O. 
Published: September 2010

AbstractThe preparation and the biological properties of a number of strongly fungitoxic compounds of the general type RSO2SCCl3 (trichloromethyl thiolsulphonates) are described in this paper. The phytotoxic character of these compounds may be lowered considerably by suitable substitution in the group R.
Theoretical interpretation of the temperature‐viscosity equation of slotte in connection with vitrification
Authors: Bêlehrádek Jan 
Published: September 2010

AbstractSlotte's equation fits the viscosimetric data on water (‐10 to 140° C) and various watery solutions; it is applicable also to the rate of diffusion in water and to the electric conductivity of weak electrolyte solutions. The term ‐a is identified as the temperature at which a supercooled liquid ceases to flow under the force applied; it is suitable as a specific characteristic of the vitreous state.
Free radical reactions involving sulphur compounds: II. The relative reactivities of substituted thiophenols with respect to hydrogen abstraction by a free trivalent carbon radical
Authors: Schaafsma Y. , Bickel A. F. , Kooyman E. C. 
Published: September 2010

AbstractIn continuation of previous work on aliphatic thiols, a quantitative comparison has been made of the relative reactivities of substituted thiophenols with respect to hydrogen abstraction by a free trivalent carbon radical.A competition method was employed involving reactions of 1‐cyano‐1‐cyclohexyl radicals with a mixture of two thiophenols in toluene solution at 110° C; 1‐cyano‐1‐cyclohexyl radicals were generated by thermal dissociation of 1,1′‐azo‐bis‐1‐cyclohexane nitrile. Relative reactivities were determined by measuring the residual amounts of thiophenols.In agreement with theoretical expectations the effects of the substituents appeared to be small, electron‐withdrawing groups decreasing the rate of the hydrogen abstraction reaction and electron‐repelling substituents increasing it; results were roughly in accordance with a Hammett ϱσ‐relationship, the value of ϱ amounting to about −0.4.
New musk odorants: Aldehydes derived from polyalkylindans. IV
Authors: Spoelstra D. B. , Weber S. H. , Kleipool R. J. C. 
Published: September 2010

AbstractIn previous communications, the preparation of acetylpolyalkylindans possessing musk type odours has been described. The present paper describes the preparation of several of the corresponding aldehydes that have a similar type of odour. These aldehydes were obtained by chloromethylation of the polyalkylindan followed by conversion of the chloro‐compound to the aldehyde.
Reactions of Bisamides. X. Condensations of N,N′‐(arylmethylene)bisamides with phenols and naphthols
Authors: Stefanović G. J. , Bojanović J. , Vandjel V. , Maksimović Z. , Mihailović M. Lj. 
Published: September 2010

AbstractN,N′‐(Arylmethylene)bisamides react with phenols by substitution of one amide residue, affording α‐acylaminobenzylcresols. Ortho‐derivatives are usually obtained, but when both ortho‐positions are occupied the reaction takes place at the para‐position, although in the latter case the yields are lower. The same compounds are obtained by condensing aldehydes, acid amides and phenols. β‐Naphthol reacts with bisamides or with aldehydes and acid amides in the same way as phenols. With α‐naphthol, however, the reaction takes a different course; both amide residues in the bisamide molecule are eliminated and benzylidenedi‐α‐naphthol, a compound of the triphenylmethane type, is obtained.
The reactivity of the bromine atom of some nitro‐bromonaphthalenes towards piperidine
Authors: van Berk P. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractReaction rate constants are determined for the piperidino‐debromination of a number of nitro‐bromonaphthalenes. The results are discussed and compared with those obtained in the catalytic deacetylation of the corresponding nitro‐acetylaminonaphthalenes in an alkaline medium.
The electrolysis of some 3‐arylpropionic acids isomerization of free radicals
Authors: Breederveld H. , Kooyman E. C. 
Published: September 2010

AbstractThe electrolysis of some substituted 3‐arylpropionic acids has been investigated with a view to a possible rearrangement of free radicals formed through discharge of anions.With 3‐phenylisovaleric acid in methanol containing an excess of sodium acetate the main product isolated was t‐amylbenzene, no rearrangement having occurred.3,3,3‐Triphenylpropionic acid in methanol containing sodium ions gave mainly the phenyl ester of 3,3‐diphenyl‐3‐methoxypropionic acid. The analogous tri‐p‐t‐butylphenylpropionic acid yielded the p‐t‐butylphenyl ester of 3,3‐di‐p‐t‐butylphenyl‐3‐methoxypropionic acid. The latter results are interpreted as involving a novel type of rearrangement of acyloxy radicals, an oxygen atom attacking an aromatic ring at its point of attachment to the C‐3 atom:magnified imageIn a discussion on the mechanism of isomerizations occurring in electrolysis, it is suggested that acyloxy radicals may also play a part rather than alkyl radicals only.
Hydrocarbures polycycliques aromatiques. IV. Sur la chimie du dibenzo[a, h] pyrène
Authors: Buu‐Hoï N. P. , Lavit Denise 
Published: September 2010

AbstractQuelques réactions de substitution du dibenzo [a,h] pyrène, hydrocarbure fortement cancériqène, ont été examinées: l'action du chlorure de sulfuryle a conduit au dérivé 7,14‐dichloré, et celle de la N‐méthylformanilide, au dérivé 7‐formylé; le 7‐méthyl‐dibenzo [a,h] pyrène, préparé à partir de ce dernier par réduction, peut être converti en 14‐formyl‐7‐méthyl‐dibenzo [a,h] pyrène, lequel, à son tour, est réductible en 7, 14‐diméthyl‐dibenzo [a,h] pyrène.
Mollisin, a dichloronaphthoquinone derivative produced by the fungus: Mollisia caesia
Authors: van der Kerk G. J. M. , Overeem J. C. 
Published: September 2010

AbstractThe isolation and characterisation of mollisin, the yellow pigment from the fungus Mollisia caesia, are described.Mollisin must be regarded as 2,3‐dichloro‐5‐hydroxy‐7‐(or 6‐) methyl‐8‐acetonylnaphthoquinone‐1,4.
The Raman and infra‐red spectra of methane‐, ethane‐ and isopropane‐phosphoryl dichloride
Authors: Gerding H. , Maarsen J. W. 
Published: September 2010

AbstractThe Raman and infrared spectra of H3CPOCl2, H5C2POCl2, and iso‐H7C3POCl2 have been investigated. Assuming the symmetry C8 for the skeletal structure CPOCl2 in these compounds, the frequencies found can be assigned fully for H3CPOCl2 and H5C2POCl2, and in the lower region in iso‐H7C3POCl2 only in part. The doubling of the P  O stretching in H5C2‐ and iso‐H7C3POCl2 can be explained from Fermi interaction with a CH deformation vibration. Of the two possible P‐Cl stretching frequencies only the symmetrical one is of high intensity.
On the theory of chromatography II
Authors: van den Hoek A. , Smit W. M. 
Published: September 2010

AbstractExperimental part.A careful experimental check carried out on the theory presented in part I, shows fair agreement between theory and experimental results. A simple chromatographic method for separating aromatic and paraffinic hydrocarbons is demonstrated.Experimental evidence is given that apparent deviations from the equilibrium theory may be due mainly to channeling and to a far less extent to diffusion or lack of equilibrium.
Isolation of dehydroepiandrosterone sulphate from the urine of a male patient with adrenal neoplasm
Authors: Huis in 'T Veld Leonora G. 
Published: September 2010

Abstract1) A compound with the empirical formula C19H27O5SNa. 2 H2O was isolated from the butanol extract of the urine of a male patient suffering from an adrenal‐cortical tumour with liver metastasis.2) It has been identified by m.p., mixed m.p., optical rotation and infrared spectrum as sodium dehydroepiandrosterone sulphate.3) Hydrolysis of this compound in a neutral medium produced i‐androstan‐6‐ol‐17‐one.
The action of p‐toluenesulphonyl chloride on pyridine‐N‐oxide (II) : The reaction of pyridine‐N‐oxide with 2‐, 3‐ and 4‐pyridyl p‐toluenesulphonate
Authors: de Villiers P. A. , den Hertog H. J. 
Published: September 2010

Abstract2‐ and 3‐Pyridyl p‐toluenesulphonate behave differently when heated with pyridine‐N‐oxide. Whilst 3‐pyridyl p‐toluenesulphonate remains practically unchanged, the 2‐pyridyl compound yields a complicated reaction mixture, from which N‐(2′‐pyridyl)‐pyridone‐2 as chief product and further N‐(4′‐pyridyl)‐pyridone‐2 and 2,3′‐dipyridyl ether have been isolated. In order to elucidate the mechanism of this reaction, we also reacted 2‐pyridyl p‐toluenesulphonate with 3‐bromopyridine‐N‐oxide; this process yielded chiefly N‐[2′‐(3′‐bromopyridyl)]‐pyridone‐2. In an orienting experiment we isolated N‐(4′‐pyridyl)‐pyridone‐4 from the mixture obtained by heating 4‐pyridyl p‐toluenesulphonate and pyridine‐N‐oxide. The picrates and mercuric chloride compounds of the reaction products and some related substances are described, and their UV absorption spectra have been measured.
Investigations on agricultural fungicides. II. Compounds structurally related to trichloromethyl thiolsulphonates
Authors: Uhlenbroek J. H. , Koopmans M. J. 
Published: September 2010

AbstractThe preparation and the fungitoxic properties of some thiolsulphonic esters (type p‐CH3C6H4SO2SR′) and of some reaction products of trichloromethanesulphenyl chloride with thiosulphonic acid salts and with thiophenols are described in this paper.
A chemical routine determination of vitamin‐D; correlation with the biological determination. (Analysis of fat soluble vitamins II))
Authors: Mulder F. J. , Roborgh J. R. , de Man Th. J. , Keuning K. J. , Hanewald K. H. 
Published: September 2010

AbstractA chemical routine method for the determination of vitamins‐D2 and ‐D3 in a number of preparations is presented. The results obtained agree very well with those obtained with the rat and chick assays respectively.A procedure for the routine determination of vitamin‐D especially for synthetic ergo‐ and chole‐calciferol is described in detail.It is a combination of a maleic anhydride addition extrapolated to zero time, and a colorimetric determination with antimony trichloride. Solutions of crystalline calciferols, irradiation products (resins and solutions in oil or volatile solvents), emulsions, solubilized solutions and dry products are covered by this method.The concentration limit after removal of volatile solvents from the products or from an extract is about 50,000 I.U./g.Interferences by fatty oils, unsaturated acids, by‐products from the irradiation, especially tachysterols, are allowed for. Interference by vitamin‐A could not be eliminated however.A determination takes about 200,000 I.U. A number of representative analyses is presented.The coefficient of variation is about 2 %.The curative test (rat assay) for vitamin‐D2 and the prophylactic test (chick assay) for vitamin‐D3 give essentially the same results (94.4 ± 16.7 % and 106.8 ± 15.8 %) as the chemical determination.It is possible to substitute the determination presented here for the bio‐assay as an analytical routine method.
Electronic spectra of mono‐ and di‐negative aromatic ions
Authors: Balk P. , Hoijtink G. J. , Schreurs J. W. H. 
Published: September 2010

AbstractThe electronic spectra in the 32‐4 kK region of the mononegative ions of naphthalene, anthracene, tetracene, phenanthrene, diphenyl, terphenyl, quaterphenyl, pyrene, perylene, triphenylene and coronene are given. The spectra of the dinegative ions of anthracene, tetracene, terphenyl, quaterphenyl and perylene have also been investigated.
The stability constants of metal complexes of some N‐dialkyldithiocarbamic acids: Part II. Copper complexes in ethanol/water mixtures of various compositions
Authors: Janssen M. J. 
Published: September 2010

AbstractThe stability constants of copper complexes of N‐dimethyl‐, N‐di‐n‐propyl‐, cyclotetramethylene‐ and 3‐carboxy‐cyclo‐pentamethylene‐dithiocarbamic acids were measured in 51.7, 75.0 and 89.0% (v/v) ethanol/water; that of the last‐mentioned compound also in water. With the aid of these results a fairly good estimate could be made of the stability constants of copper complexes of the three first‐mentioned acids in water.
Chemistry of acetylenic ethers XXVI. Ethyl orthothioacetate and 1,1‐bis‐ethylthioethene (ketene diethyl mercaptal)
Authors: Volger H. C. , Arens J. F. 
Published: September 2010

AbstractThe preparation of ethyl orthothioacetate (VII) from acetyl chloride and excess of ethanethiol in the presence of zinc chloride has been studied. The substance can easily be converted into 1,1‐bis‐ethylthioethene (VI), which can also be obtained directly from acetyl chloride (or ethyl acetate) and two moles of ethanethiol under the influence of zinc chloride. 1,1‐bis‐Ethylthioethene (VI) is produced also by the action of potassium tert.butoxide on ethylthioacetaldehyde diethylmercaptal (X).
Electronic spectra of alternant hydrocarbon mononegative ions
Authors: Balk P. , de Bruijn S. , Hoijtink G. J. 
Published: September 2010

AbstractThe electronic spectra of the mononegative ions of naphthalene, anthracene, tetracene, phenanthrene, pyrene, perylene, biphenyl, terphenyl and quater‐phenyl have been qualitatively interpreted with the aid of L.C.A.O.‐M.O. calculations including configuration interaction. The calculated dipole strengths are on the average about twice to three times as high as the experimental values. In a relative sense, however, the agreement between observed and calculated dipole strengths is satisfactory.
A kinetical investigation of the reaction between amides and formaldehyde
Authors: Ugelstad J. , de Jonge J. 
Published: September 2010

AbstractThis paper deals with the kinetic measurement of the reaction between formaldehyde and the amides of carboxylic acids and urea.It is shown that the formation of a methylol amide proceeds by a bimolecular reaction, while its decomposition is a monomolecular reaction. The reactions are catalysed by H3O+ and OH− ions and show general acid catalysis. General base catalysis was found in the urea‐formaldehyde system, but could not be detected in reactions of formaldehyde with amides of carboxylic acids. A mechanism for the reactions of formaldehyde with amides in general (including urea) is proposed.In strongly alkaline solution the rates of decomposition of methylol amides were found to be independent of the hydroxyl ion concentration. The acid dissociation constant of some methylol amides have values of about 10−14 moles 1−1 at 0° C.
Chemistry of acetylenic ethers XXVII: Reactions of 1,1‐diazido‐1‐ethoxyethane with nucleophilic reagents
Authors: Sinnema Y. A. , Arens J. F. 
Published: September 2010

AbstractThe reactions of 1,1‐diazido‐1‐ethoxyethane with several nucleophilic reagents have been studied. Strong nucleophilic reagents rapidly substitute both azido groups. Weak nucleophiles require a reaction temperature of about 70° C. At this temperature nitrogen splits off from the diazide, so that side reactions may occur. One of these is the reduction of an azido group by a thiol. Another is the “reductive” removal of an azido group by the action of hydrazoic acid. The latter reaction can be applied for the conversion of ethoxyethynylcarbinols into α, β‐unsaturated aldehydes.
Hydrocarbures Polycycliques Aromatiques: VII. Synthèse du 2‐phényl‐ et du 2‐p‐biphénylanthracène par la réaction d'Elbs
Authors: Buu‐HoÏ N. P. , Lavit Denise , Jacquignon Pierre 
Published: September 2010

AbstractOn décrit une nouvelle synthèse du 2‐phenylanthracène, par pyrolyse du 4‐o‐toluoylbiphényle; le 2‐p‐biphénylanthracène, non encore décrit jusqu'à présent, a été synthétisé de façon analogue par pyrolyse du 4′‐o‐toluoyl p‐terphényle. Cette dernière cétone est préparée, en méme temps que le 4′,4″‐bis(o‐toluoyl)‐p‐terphényle, dans la réaction de Friedel‐Crafts entre le chlorure d'o‐toluoyle et le p‐terphényle. Les spectres d'absorption et de fluorescence du 2‐phényl‐ et du 2‐p‐biphénylanthracène ont été déterminés.
Thermodynamic properties of mixtures of alkanes differing in chain length, IV: Volumes of mixing
Authors: Desmyter A. , van der Waals J. H. 
Published: September 2010

AbstractThe change in volume on mixing two alkanes of different molecular weight has been studied in order to provide further experimental data for testing current theories of solutions. A description is given of a dilatometer which permits a determination of the volume of mixing as a function of composition over a wide range of concentrations in a single experiment.Binary mixtures of n‐alkanes (C5 + C16, C6 + C16, C7 + C16, C8 + C16, C10 + C16 and C6 + C12) and the system iso‐octane‐n‐hexadecane were investigated in the temperature range of 20‐50° C. In all cases a contraction is observed which increases with temperature and with the difference in chain length of the two components. It ranges from 0.03% for the system n‐decane/n‐hexadecane to about 0.5% for a mixture of n‐pentane and n‐hexadecane at room temperature.It appears that the excess volumes of binary mixtures of n‐alkanes can be predicted from the molal volumes of the pure n‐alkanes on the basis of Brønsted's principle of congruence.
Foam stability. Part I. Structure and stability of foams
Authors: de Vries A. J. 
Published: September 2010

AbstractA critical survey is given of the various factors governing the stability of foams. Special attention is paid to the role of surface tension and to the importance of Gibbs' effect of surface elasticity of thin liquid films: The contribution of the last factor to the free energy of deformation of foam lamellae is estimated.The two different forms of foam structure which may occur, foams with spherical bubbles and foams containing polyhedral cells, are described and their differences are explained in particular with respect to both processes responsible for the spontaneous destabilization of foams: transfer of gas between the bubbles and collapse of the lamellae.
Untersuchungen ueber Nitroderivate des Pyridins
Authors: Czuba Wladyslaw , Plaźek Edwin 
Published: September 2010

Abstract2,6‐Dinitro‐3‐hydroxypyridin bildet sich bei der Nitrierung des 2‐Nitro‐3‐hydroxypyridins in Gegenwart von Essigsäureanhydrid. Mit PCl5 entsteht daraus 2,6‐Dinitro‐3‐chlorpyridin. Diese Verbindung tauscht bei der Einwirkung von NH2‐NH2, NH3, KOH nicht das Chloratom, sondern ausschliesslich die NO2 Gruppe in 2‐Stellung aus.
The preparation of pyridine derivatives from halogenopyridines by means of the Grignard Reaction VI: Preparation of 2‐allylpyridine from 2‐bromopyridine and of 2,6‐diallylpyridine from 2,6‐dibromopyridine
Authors: Wibaut J. P. , Bloemendal H. 
Published: September 2010

AbstractThe synthesis of 2‐allylpyridine and 2,6‐diallylpyridine by the reaction of allyl bromide with 2‐pyridylmagnesium bromide and pyridenyl‐2,6‐bis‐magnesium bromide, respectively, is described.
On the sensitivity to light of polyene fungicides
Authors: Hendriks B. , Berends W. 
Published: September 2010

AbstractDuring recent years various fungicides having a polyene structure have been isolated from streptomycetes. During the study of the action mechanism of a new representative of this group, pimaricin, it was established that the suppression of respiration of yeast by this substance was completely neutralised, if at the same time riboflavin and light were present. The cause of this phenomenon appears to be traceable back to a photodynamic destruction of pimiracin under the influence of riboflavin.The effect is not restricted to riboflavin; some other colouring matters also possess this property. Ascorbic acid and hydroquinone repress the photodynamic reaction greatly. Arguments are presented for supposing that hydroxyl radicals are responsible for the annulment of the polyene group of the fungicide. So far hydrogen peroxide has been regarded as the substance bringing about the photo‐dynamic reactions.
Ionylamines II: Synthesis of tetra‐ and hexa‐hydro‐ψ‐ionylamines and their spasmolytic action
Authors: Moed H. D. , Kralt T. , van Dijk J. 
Published: September 2010

AbstractThe synthesis and properties of amines with the C‐skeleton of ψ‐ionone are described. The spasmolytic activities of the compounds have been determined. The results are discussed and the conclusions are reached that the ψ‐ionylamines form a series of compounds with high musculotropic spasmolytic activity and that in this series there exists a fairly clear and regular relationship between chemical structure and spasmolytic activity.