bluuebunny/crossref_metadata_2025_split huggingface dataset:
The basicities of the methyl 1,2‐benzanthracenes
Authors: Mackor E. L. , Dallinga G. , Kruizinga J. H. , Hofstra A. 
Published: September 2010

AbstractThe basicity constants of eleven methyl 1,2‐benzanthracenes and the absorption spectra of their conjugate acids were measured in anhydrous hydrofluoric acid. It could be shown that in every case two isomeric ions, in which the proton has reacted with either of the two meso carbon atoms, were present.The basicity constants of the conjugate acids could be determined. The relative increase of this constant on methyl substitution is compared with theory.
Molecular complexes and their spectra. VI. Some problems and new developments
Authors: Mulliken Robert S. 
Published: September 2010

AbstractAlthough the charge‐transfer theory probably affords a correct general account of major aspects of the structure and spectra of molecular complexes, its application to the detailed structures of particular types of complex presents a variety of problems whose definitive solution will require much new experimental and theoretical research, but should then yield many interesting conclusions. The effects of London dispersion forces and classical electrostatic forces as well as charge‐transfer forces must always be taken into account. Orientation isomerism, acceptation cross‐sections of acceptor molecules, paraffin‐halogen interactions and their contact charge‐transfer spectra, intensity problems, the blue shift of the iodine visible band in the spectra of iodine complexes, and complexes with two charge‐transfer spectra, are discussed below.
Etude Spectroscopique des Complexes Moléculaires: Halogènes‐Substances Organiques”
Authors: D'Or L. , Alewaeters R. , Collin J. 
Published: September 2010

AbstractLe spectre‐infrarouge de solutions de chlore et de brome dans le benzène a été étudié. Les bandes à 526 cm−1 et à 301 cm−1 (dans l'état libre 557 cm−1 et 231 cm−1), respectivement celles qui disparaissent après élimination du halogène, sont attribuées aux molécules de halogène engagé dans un complexe avec le benzène. La structure possible de ces complexes est discutée.
Complexes of aromatic nitrocompounds
Authors: Bier A. 
Published: September 2010

AbstractEquilibrium constants, enthalpy and entropy of formation, together with maxima of absorption, are recorded for a number of molecular compounds of symm.‐trinitrobenzene with aromatic hydrocarbons and aromatic amines in chloroform solution. The data are compared with van de Stolpe's findings on complexes of iodine, and some other regularities are discussed.
Synthesis and properties of the chlorination products of methyl 4‐Amino‐2‐Hydroxy‐Benzoate. II
Authors: van der Stelt C. , Nauta W. TH. 
Published: September 2010

AbstractWhereas methyl 1,3,3,5,5,6‐hexachloro‐cyclohexanedione‐2,4‐carboxylate‐1 (XIV) was obtained by the chlorination of methyl 4‐amino‐2‐hydroxy‐benzoate (XIII) (P.A.S. methyl ester) in a mixture of glacial acetic acid and hydrochloric acid (s.g. 1.19), chlorination of XIII in carbon tetrachloride yielded two isomers with gross formula C8H4O3NCl7 (XXIII and XXIV), to which the structure of a methyl 1,3,3,5,5,6‐hexachloro‐4‐chlorimino‐cyclohexanone‐2‐carboxylate‐1 is assigned. The isomerism of XXIII and XXIV is thought to be of the syn‐anti type with regard to the attachment of the chlorine atom to the nitrogen. Reduction with stannous chloride converted both XXIII and XXIV into methyl 4‐amino‐3,5‐dichloro‐2‐hydroxy‐benzoate (XV). Hydrolysis of the two isomers led to the same nitrogen‐free compound C8H4O4Cl0, which is believed to be a stereo‐isomer of XIV and to which consequently the same name is attributed (XXV). With regard to the chlorine atoms attached to the carbon atoms 1 and 6, XIV is supposed to be the cis and XXV the trans form. Both XIV and XXV could be converted into methyl 3,5‐dichloro‐2,4‐dihydroxy‐benzoate (XVIII) by reduction. A mixture of XIV and XXV was obtained by chlorination of XIII, XV, XVIII and methyl 2,4‐dihydroxy‐benzoate in glacial acetic acid alone. In alkaline medium XXV decomposed, dichloro acetic acid and monomethyl trichloroglutaconate being the decomposition products. With hypochlorous acid XXV reacted to give trichloro‐acetic acid and methyl pentachloro‐glutarate (XXVI). Aniline converted XIV and XXV into two isomeric addition products: C14H11O4NCl6. Whereas XXV is reduced to XVIII by an aqueous potassium iodide solution, XIV yielded a compound for which the structure of a methyl 1,3,5,5,6‐pentachloro‐2‐hydroxy‐cyclohexene‐2‐one‐4‐carboxylate‐1 (XXIX) is made plausible. Further reduction converts XXIX into XVIII. Our view on some of the structures is supported by evidence from U.V. and I.R. spectra. Of several compounds tested, XXIV showed a considerable fungicidal activity.
An electron‐diffraction investigation into the vapours of cyclohexanone and 2‐methylcyclohexanone: Second communication on the molecular structures of ketones
Authors: Romers C. 
Published: September 2010

AbstractThe vapours of cyclohexanone and 2‐methylcyclohexanone are investigated with the aid of electron‐diffraction. The bond distances are 1.54 ± 0.01 Å, 1.24 ± 0.02 Å, and 1.09 ± 0.02 Å for CC, CO, and CH respectively. All the carbon bond angles are 109.5 ± 2.5°, with the exception of the bond angles of the carbonyl carbon atom, which are 117 ± 3° and 121.5 ± 1.5° for CCC and CCO angle respectively.The methyl group of 2‐methylcyclohexanone is found in equatorial orientation.
The behaviour of membranes between electrolyte solutions : IV. Electrochemically active precipitates in membranes; the membrane potential at the barium sulphate‐cellophane membrane
Authors: Hirsch‐Ayalon P. 
Published: September 2010

AbstractImpregnated membranes show peculiarities as to membrane potentials and permeability. The special behaviour of such membranes is examined by means of the example of a BaSO4‐cellophane membrane.The membrane potential at the BaSO4 membrane is affected in a different way by different electrolytes in the adjacent solutions. The relation between the membrane potential and the pH of the adjacent solutions is expressed inMP = 2.3026 RT/F · (pH1 − pHo).Under the given conditions the membrane is impermeable to Ba2+ and SO42−. permeable to H+ and OH−.
Chemical and pharmacological data on aminoethoxypyridines and their acetyl derivatives
Authors: Bijlsma U. G. , den Hertog H. J. 
Published: September 2010

AbstractSyntheses of 2‐amino‐4‐ethoxy‐, 3‐amino‐2‐ethoxy‐, and 3‐amino‐4‐ethoxypyridine are described. A survey is given of the group of aminoethoxypyridines, all the possible members of which are now known. The picrates and monoacetyl derivatives of these compounds have been prepared.The antipyretic effect of the monoacetyl compounds of nine isomeric amino‐ethoxypyridines is compared with that of phenacetin (= p‐acetylaminoethoxy‐benzene). Not the para‐substituted, but some of the other isomers compete with the benzene derivative.3‐Amino‐4‐ethoxypyridine may be considered to be an analogon of the 1‐alkoxy‐2‐amino‐4‐nitrobenzenes, sweeting substances, studied by Blanksma and Verkade; it has no sweet, but a bitter taste and possesses an anaesthetic effect which approaches that of procaine.
The ortho/para distribution of methylol groups in the reaction of phenol and formaldehyde. I
Authors: de Jong J. I. , Dijkstra R. , de Jonge J. 
Published: September 2010

AbstractIn the reaction between phenol and formaldehyde in aqueous solution at 90° C and pH = 5.5‐6.5 about 58% ortho substitution and 42 % para substitution takes place initially.A colorimetric method for the determination of methylol phenols in solution is described.
Chemistry of acetylenic ethers. XIX. The reaction of aldehydes with ethoxyethynylmagnesium bromide
Authors: Postma J. C. W. , Arens J. F. 
Published: September 2010

AbstractThe reaction of aldehydes with ethoxyethynylmagnesium bromide does not yield the expected secondary carbinols. In the case of aromatic aldehydes the reaction products are formed from two molecules of the aldehyde and one molecule of the acetylenic compound.The structures of these compounds have been established by several transformations (see reaction scheme I) and the chemistry of their formation has been studied (reaction scheme II).Aliphatic aldehydes and ethoxyethynylmagnesium bromide give products derived from three molecules of the aldehyde and one of the acetylenic compound. In this case also the structures of the different transformation products have been investigated (reaction scheme III).
La réaction de l'ammoniac sur le mercure en présence de traces d'eau
Authors: Michels A. M. J. F. , Dumoulin E. M. L. , Gerver J. H. 
Published: September 2010

AbstractIl apparait dans certains cas des phénomènes qui semblent indiquer l'existence d'une action de l'ammoniac sur le mercure, aboutissant à la formation d'un composé explosif. Nous montrons ici qu'il s'agit de la formation d'un oxyde d'amminomercure, où des traces d'eau fournissent l'oxygène. Un ammoniacate plus stable se forme, avec plusieurs molécules de NH3.
Formation of α‐pyridones from α‐acylbenzyl cyanides
Authors: Wajon J. F. M. , Arens J. F. 
Published: September 2010

AbstractHeating α‐acetylbenzyl cyanide I with a mixture of acetic acid and sulphuric acid leads to the formation of the α‐pyridone IV, formed by condensation of the amide II with the ketone III, both of which originate from the cyanide I (see scheme 1). A similar reaction has been observed with some other α‐acylbenzyl cyanides.Several α‐pyridones have been prepared by condensation of α‐acylbenzyl cyanides Ia with a variety of ketones IIIa (scheme 2).
Reactions of amino‐acids and peptides with aromatic aldehydes I
Authors: Havinga E. , Spitzer E. L. T. M. 
Published: September 2010

AbstractThe reactions of some glycine derivatives with aromatic aldehydes (“Plöchl‐Erlenmeyer reaction”) have been studied,a) using acetic anhydride as an acetylating medium and sodium acetate as a catalyst according to the conditions elaborated by Dakin;b) according to the directions of Bergmann et al. in which ethanol is used as the solvent and no extra catalyzing agent is added.It was confirmed that for method a) glycine residues with a free carboxyl group are essential, whereas for method b) it is necessary for the glycine residue to have a free amino group. Other amino‐acid residues may also react but less readily than glycine and possibly in a different way. Some new condensation products are described.
Studies in the pyrazole series, VI, some derivatives of 3,5‐dimethyl‐1‐(3′‐quinolyl) pyrazole
Authors: Scott F. L. , Ahearne A. , Reilly J. 
Published: September 2010

AbstractThe synthesis of the prototype (I A) of a new class of pyrazoles, the 1‐(3′‐quinolyl) pyrazoles, is described. The chlorination, and bromination of (I), to yield the 4‐halogenopyrazolyl compounds (I B and I C) has been shown to involve the hydrohalide salts of (I B) and (I C) as unstable intermediates.
On the reaction of acetophenone with formaldehyde
Authors: Heeringa L. G. , Beets M. G. J. 
Published: September 2010

AbstractThe discrepancy between the results of Fuson's work and our own on the alkali‐catalyzed reaction of acetophenone with formaldehyde in alcohol has been studied. Several compounds have been isolated and identified but 5‐benzoyl‐m‐dioxan, which according to Fuson should be the main reaction product, has not been found.
Acid anilides. VI. Quantitative paper chromatographic analysis of fatty acid anilides
Authors: de Jonge A. P. , Verhage A. 
Published: September 2010

AbstractFrom relevant investigations, evidence had been obtained that a quantitative analysis of saturated fatty acid anilides is possible. In the present paper a description of this method of analysis is given, with particular reference to the behaviour of the anilides during analysis.
Steric effects on mesomerism. XV. Comparative investigations involving ultra‐violet absorption spectra, molecular refractions, basic strengths, and rates of reaction of derivatives of nitrobenzene
Authors: Wepster B. M. 
Published: September 2010

AbstractFor several series of compounds the variation in ultra‐violet spectrum, molecular refraction, basic strength, and rate of reaction, due to the presence of a more or less strong inhibition of mesomerism, has been investigated. The members of these series are derivatives of nitrobenzene, para‐nitroaniline, and para‐nitroacetanilide, substituted in such a way that the steric inhibition concerns exclusively the mesomeric interaction between the nitro group and the rest of the system.When comparing these data, it appears that the percentual decrease of the importance of the mesomerism according to each of the criteria in question is approximately the same; several linear relations are found. The non‐linearity between the extinction coefficients of nitrobenzenes and para‐ nitroanilines is interpreted as the consequence of a decrease of the average angle of twist of the nitro group upon substitution of an amino group in para position.By extrapolation of the straight lines found, data are obtained about:
the exaltation in the molecular refraction of nitrobenzene resulting from the mesomeric interaction between benzene ring and substituent.
the energy of mesomerism in para‐nitroaniline due to the interaction of the substituents.
the relative importance of mesomeric and inductive effects of the nitro group for the basic strength of para‐nitroaniline, and for the rate of deacylation of para‐nitroacetanilide.
the meta/para ratio of the inductive effect in benzene derivatives.
Finally the conclusions resulting from the data with regard to the effective sizes of alkyl groups are discussed.
The energy difference between the rotational isomers of some simple dipolar compounds in the liquid state
Authors: Ketelaar J. A. A. , van Meurs N. 
Published: September 2010

AbstractStarting from the dipole moments of 1,2‐dibromoethane, 1,3‐dibromopropane and ethyl oxalate and isopropyl oxalate the energy difference between the rotational isomers of these compounds was calculated. The presence of only two stable conformations for every dipole substance was incorporated in the calculation. The energy values computed for both dibromides were in good agreement with those obtained from infra‐red and Raman measurements.
Preparation of pure lactulose
Authors: Bots J. P. L. 
Published: September 2010

AbstractA simple method is described for the preparation of lactulose octaacetate by acetylation of the reaction product obtained by treating lactose with lime.Pure lactulose was prepared by deacetylation of lactulose octaacetate with 0.1 N‐HCl at 71° C.
The action of hydrazine on 1,4‐DI‐(p‐ethoxybenzoyl)‐butane. 3,8‐DI‐p‐ethoxyphenyl‐4,5,6,7‐tetrahydro‐1,2‐diazocine
Authors: van der Zanden J. M. , de Vries G. 
Published: September 2010

AbstractThe action of hydrazine on 1,4‐di‐(p‐ethoxybenzoyl)‐butane affords products similar to those obtained in the reaction between 1,4‐dianisoyl‐butane and hydrazine1).
Reactions of amino‐acids and peptides with aromatic aldehydes II) ): Condensations of sarcosine esters under the influence of ultra‐violet irradiation
Authors: Spitzer E. L. T. M. , Havinga E. 
Published: September 2010

AbstractThe reactions of the ethyl and methyl esters of sarcosine with aromatic aldehydes under the influence of ultra‐violet irradiation have been studied. From the condensation reaction of each of the esters with p‐nitrobenzaldehyde three stereoisomeric racemic oxazolidines were isolated in a pure form. Probable configurations of these compounds are indicated. The condensation of sarcosine ethyl ester with p‐nitrosalicylic aldehyde also led to the isolation of three reaction products, two being analogous to the oxazolidines obtained with p‐nitrobenzaldehyde, the third having a different, as yet unelucidated structure. A preliminary investigation of the reaction mixture obtained from condensing the sarcosine ester with p‐chlorobenzaldehyde yielded one of the oxazolidines in a pure state.
Le point de charge nulle des sols lyophobes de AgI, AgBr et AgCl dans les mélanges eau‐acétone
Authors: Overbeek J. Th. G. , Watillon A. , Serratosa J. M. 
Published: September 2010

AbstractD'après Mackor, la variation du point de charge nulle des suspensions colloïdales de AgI dans les mélanges eau‐acétone est dû tout d'abord au saut brusque du potentiel x de Lange aux faibles concentrations en acétone, et ensuite, à la variation de l'enthalpie libre de solvatation de l'ion Ag+ aux plus fortes teneurs en acétone. Utilisant la méthode microélectrophorétique à fond noir, nous trouvons pour AgI et AgBr un saut du potentiel x de 225 mV et pour AgCl un saut de 105 mV. Toutefois, la variation de l'enthalpie libre de solvatation de l'ion Ag+ pour les trois types de suspensions colloïdales est identique, ce qui vérifie parfaitement l'hypothèse de Mackor.
On the theory of chromatography I
Authors: Smit W. M. , van den Hoek A. 
Published: September 2010

AbstractA theory of the chromatography of binary liquid mixtures resembling that of de Vault is given. In the present theory, however, preferential adsorption isotherms are used whereas in de Vault's theory absolute isotherms are employed. It is shown that de Vault's theory leads to impossible consequences. Unlike the absolute isotherms, the preferential adsorption isotherms of the components of a liquid mixture are experimentally determinable and may become negative. As a result of the introduction of preferential adsorption isotherms into the theory of chromatography the theory can be checked by experiments and possibilities can be predicted that could not be foreseen by de Vault's theory. Further, the influence of the adsorption of the “solvent” is automatically accounted for when preferential adsorption isotherms are used. Neglect of the adsorption of the solvent is not generally allowable, not even when some very general conclusions concerning three component systems are aimed at. The present theory has been subjected to a careful experimental check showing fair agreement between theory and experimental results. The experiments are described in part II.
Electrometric end points in the argentometric determination of cerium
Authors: Sant B. R. 
Published: September 2010

AbstractVolumetric determination of cerium (IV), based on its reduction to cerium (III) by excess KSCN and the electrometric titration of the excess against standard silver nitrate, is described. It is shown that the potentiometric end points in the KSCN‐AgNO3 reaction in the presence of sufficiently large concentrations of sulphuric acid and/or cerium(III) yield accurate results. Amperometric studies on the cerium (IV)‐thiocyanate reaction are now under investigation.
Hydrolysis of ethyl acetate in hydrochloric acid solutions containing mannitol
Authors: Sadek Hussein , Elamayem M. S. Abu 
Published: September 2010

AbstractHydrolysis of ethyl acetate in 0.05 N‐HCl at 25°, 30°, 35°, and 40° C was carried out in the absence and presence of mannitol. The addition of mannitol lowers the velocity constant while the activation energy remains constant. The reaction is accompanied by reduction of the entropy of activation as a consequence of solvation effects. The results agree with Laidler's theory of electrostatic interaction.
A one‐electron L.C.A.O.M.O. treatment of hydrocarbon negative ions
Authors: Balk P. , de Bruijn S. , Hoijtink G. J. 
Published: September 2010

AbstractIt is shown that the one‐electron L.C.A.O.M.O. treatment is much more reliable for hydrocarbon mono‐ and di‐negative ions than for hydrocarbon molecules. The results of this treatment in which both the interaction between non‐adjacent 2p‐orbitals and overlap have been included, have been compared with polarographic half‐wave potentials, giving a mean value of the resonance parameter for adjacent 2p‐orbitals: β′o = −2.60 ± 0.030 eV.It appears that by neglecting both interaction between non‐neighbouring 2p‐orbitals and overlap the same mean value is obtained, whereas the inclusion of overlap only, leads to a noticeably less negative value: β′o = −2.30 ± 0.020 eV. Apparently these effects of overlap and interaction between non‐neighbouring 2p‐orbitals compensate each other.
Electrochemical researches on paraffin membranes II: The specificity of special paraffin membranes as calcium‐ion electrodes
Authors: Tendeloo H. J. C. , Krips A. 
Published: September 2010

AbstractA membrane consisting of a mixture of pure paraffin of low melting point, a calcium salt of low solubility in water and a non‐ionogenic detergent can be used as an electrode for the determination of calcium‐ion concentrations, viz. pCa. Investigations are here reported on solutions of mixtures of CaCl2 and KCl, or MgCl2.
Chemistry of acetylenic ethers XXVIII: α,α‐Dichlorodiethyl ether and its use for the preparation of acyl chlorides
Authors: Heslinga L. , Katerberg G. J. , Arens J. F. 
Published: September 2010

AbstractAddition of two equivalents of hydrogen chloride to ethoxyacetylene yields α,α‐dichlorodiethyl ether (III). This substance reacts easily with carboxylic acids to yield acyl chlorides (X). α, α, β ‐Trichlorodiethyl ether (XIII), obtainable in two steps from trichloroethene (XI), shows the same reaction.
Chemistry of acetylenic ethers. XXIX.: Reactions of acetylenic ethers with some aromatic isocyanates. Formation of derivatives of 2‐quinolone
Authors: Nieuwenhuis J. , Arens J. F. 
Published: September 2010

AbstractEthoxyacetylene slowly adds phenyl isocyanate to yield 4‐ethoxy‐2‐quinolone I (R=H). A similar reaction occurs with p‐tolyl isocyanate.From the Grignard derivative of ethylthioacetylene and phenyl isocyanate the anilide of ethylthiopropynoic acid VIII is obtained. The corresponding reaction with ethoxyacetylene does not yield a pure product.
The decomposition of organic hydroperoxides: Part I. Catalytic effects of the second group metal stearates on the decomposition of tetralyl hydroperoxide
Authors: van Leeuwen H. B. , Wibaut J. P. , Bickel A. F. , Kooyman E. C. 
Published: September 2010

AbstractThe decomposition of tetralyl hydroperoxide has been studied at 100° C in chlorobenzene solution, using glass reaction vessels.The uncatalyzed reaction is very slow; initial decomposition may show irregularities depending on the pretreatment of the walls of the reaction flasks.Whereas the stearates of beryllium, barium and mercury have little influence when added in amounts of a few percent molar based on the hydroperoxide, decomposition is markedly accelerated by cadmium, calcium, strontium, zinc and magnesium stearate; the effect increases in the order mentioned.From the fact that the catalytic decomposition is suppressed by a phenolic inhibitor (2,6‐di‐t‐butyI‐4‐methylphenol) only in the case of magnesium stearate, it is concluded that a free radical chain decomposition occurs only in the presence of the latter catalyst.
The temperature variation of orthobaric density difference in liquid‐vapour systems. III. Alcohols
Authors: Costello J. M. , Bowden S. T. 
Published: September 2010

AbstractThe density of a variety of alcohols has been measured over ranges of temperature below and above the boiling point. It is shown that the variation of orthobaric density difference with temperature may be represented fairly well by the Verschaffelt equation. In general the exponent of the equation is substantially lower than that found for normal liquids, and its value depends on the temperature range examined.
Phosphatide acids and derivatives. VII. The use of silver phenyl benzyl phosphate for the synthesis of monophenyl esters of phosphatidic acids
Authors: Pzn S. Mostert , Stegerhoek L. J. , Verkade P. E. 
Published: September 2010

AbstractThe preparation of phenyl benzyl esters of phosphatide acids and their debenzylation to the monophenyl esters by hydrogenolysis in the presence of a palladium/active carbon catalyst is described.