bluuebunny/crossref_metadata_2025 huggingface dataset:
A liquid bath precision thermostat ranging from about 20° C to over 360°C
Authors: Smit W. M. , van Wijk H. F.
Published: September 2010

A thermostat suitable for the checking of mercury thermometers is described. The bath liquid consists of a mixture of sodium and potassium. The thermostat can be used from temperatures somewhat above room temperature to over 360° C. Its accuracy is ± 0.002° C at 330° C. At lower temperatures the accuracy is better than ± 0.001° C. The thermostat attains equilibrium at any desired temperature within three hours.
Investigations on sterols VIII : Some hitherto unknown irradiation products of ergosterol
Authors: Westerhof P. , Buisman J. A. Keverling
Published: September 2010

From the “toxisterol2” mixture obtained by prolonged U.V. irradiation of ergosterol two or possibly three hitherto unknown compounds have been isolated in the form of crystalline esters.
Bromination and nitration of 2‐hydroxypyridine‐N‐oxide
Authors: van Ammers M. , den Hertog H. J.
Published: September 2010

From the reaction mixtures obtained by brominating and nitrating 2‐hydroxypyridine‐N‐oxide the sole disubstituted products isolated were the 3,5‐derivatives. The course of the bromination and nitration of 2‐hydroxypyridine‐N‐oxide differs from the analogous reactions of 2‐hydroxypyridine only in an increased reaction velocity.
The energetics of highly charged spherical micelles as applied to sodium lauryl sulphate
Authors: Overbeek J. Th. G. , Stigter D.
Published: September 2010

The electrical free energy of micelle formation is treated for spherical micelles with a Gouy type double layer, allowing for high surface charge. Use is made of double layer computations carried out by Hoskin for spherical particles with high surface potential. A procedure is developed for interpolating between Hoskin's results. A correction is applied for the difference between the smeared out surface charge as in the model calculations and the actual assembly of discrete charges.

From the equilibrium equation for micellization in which this electrical free energy occurs together with terms depending on the concentrations of free ions and of micelles the non‐electrical part of the standard free energy of micelle formation (W‐TΔSo) can be calculated.

The method is applied to micelles of sodium lauryl sulphate in aqueous sodium chloride solutions. In this system W‐TΔSo is found to be nearly independent of micelle size and slightly above 1 kT per carbon atom in the chain. Comparison with other data on the free energy change in the transfer of aliphatic chains from water to non‐polar surroundings shows excellent agreement.
The reaction between bromoacetate and thiosulphate ions in dilute solution
Authors: Erkelens J. , Korvezee A. E.
Published: September 2010

The rate of the reaction between thiosulphate and bromoacetate in very dilute aqueous solutions has been redetermined. The variation of the rate constant with the ionic strength of the solution can be predicted from the “activated complex” theory combined with the Debye‐Hückel limiting law. In the concentration range where the latter is valid our data are in agreement with the theoretical relationship and with the most plausible reaction mechanism.
Chemistry of acetylenic ethers. XVIII: Reactions of ethoxyethynylcarbinols with amines
Authors: Postma J. C. W. , Arens J. F.
Published: September 2010

Ethoxyethynylcarbinols, which can be prepared from carbonyl compounds and metallic derivatives of ethoxyacetylene, react with amines in three different ways.

Strongly basic amines like diethylamine mainly cause reaction A, dissociation of the carbinol into the carbonyl compound from which the carbinol was derived, and ethoxyacetylene (which reacts further with the amine used). Very weakly basic aromatic amines like p‐nitroaniline catalyze the rearrangement into α,β‐unsaturated esters (reaction B), whereas aromatic amines like aniline yield amides of β‐hydroxy‐acids with evolution of ethylene (reaction C).
The methylation of 3‐hydroxypyridine
Authors: Prins D. A.
Published: September 2010

A convenient method for the preparation of 3‐methoxypyridine and its N‐oxide is described.
The isothermal compressibilities of liquids
Authors: McGowan J. C.
Published: September 2010

For unassociated liquids, the following relationship between the surface tension (γ) and the isothermal compressibility (χT) is found

This relationship leads to an expression for the parachor (vp)

and to the following equation for the variation of isothermal compressibility with temperature (T)

where Tc is the critical temperature of the liquid, M its molecular weight, d1 its density and dg the density of the vapour in equilibrium with it; k is the Eötvös constant.
Studies in silico‐organic compounds. XXXII. The preparation of additional sulfides and polysulfides
Authors: Minklei Alfred O. , Decker Quintin W. , Post Howard W.
Published: September 2010

The preparation of several new silicon containing sulfides is described. Also, a disila‐alkyl polysulfide, prepared by peroxide oxidation, is reported.
The mutarotation and ionization of D‐glucose in alkaline solution II
Authors: Los J. M. , Simpson L. B.
Published: September 2010

Measurements of the rate of mutarotation of D‐glucose in unbuffered alkaline solutions, with a pH meter, have been continued with a more sensitive instrument. All available data have been reinterpreted on the basis of the following assumptions:

(a) The mutarotation in alkaline solution of D‐glucose is first order in the glucose concentration and the specific rate constant is given by

(b) The catalytic constants kGα and kGβ are related by an expression derived from the Brønsted catalysis law

where c was taken as equal to 0.4.

It has been shown that the latter assumption (b) could eliminate the difficulty experienced in the preceeding communication 1) of a kOH value which was strongly dependent on the glucose concentration.

The results provide new values for the catalytic constants of hydroxyl ions, of the α and β glucosate ions, and for the hydrolysis and ionization constants of α and β D‐glucose. Corresponding equations have been given.

A critical discussion of the errors in the method has been included.

The results prove, among other things, that the reason for the greater acidity of β D‐glucose than of the corresponding α form (as established in this investigation) lies in the considerable difference in entropy change upon ionization for the two different isomers.
Steric effects on mesomerism. XVI). Comparative investigations involving ultra‐violet absorption spectra, molecular refractions, rates of reaction, and basic strengths of aromatic amines
Authors: Wepster B. M.
Published: September 2010

In several series of compounds with a more or less strong inhibition of the mesomerism, the variation in ultra‐violet spectrum, molecular refraction, rate of reaction, and basic strength has been investigated. The members of the present series are mainly derivatives of aniline, dimethylaniline, and their para‐nitro and para‐ethoxycarbonyl derivatives. They have been so chosen that any steric inhibition that may occur, concerns exclusively the mesomeric interaction between the amino group and the rest of the system.

Upon comparison of the data it is found that none of the aniline derivatives examined shows any appreciable steric inhibition of the mesomerism. It is also on this basis that the relatively low basic strengths of ortho‐alkylanilines have been interpreted as due to steric hindrance to solvation.

In the case of the dimethylaniline derivatives, where inhibition of the mesomerism occurs, linear relations are found between the extinction coefficient ϵ and the exaltation of the molecular refraction. Further the reaction rate data are in agreement with the linear relation between ϵ and the mesomeric energy found earlier. It is also on this basis that an estimation has been made of the magnitude of the anomalies in the basic strengths of ortho‐alkyl dimethylanilines. These have been interpreted as being at least mainly due to steric hindrance to solvation.

By extrapolations of the straight lines found, data have been obtained on the exaltations of the molecular refractions in dimethylaniline and ethyl para‐dimethylaminobenzoate, and also on the relative importance of inductive and mesomeric effects for the alkaline hydrolysis of the latter compound.
The interaction of sodium, potassium, calcium, and magnesium with human serum albumin, studied by means of conductivity measurements
Authors: van Os G. A. J. , Koopman‐van Eupen J. H. M.
Published: September 2010

To test the usefulness of conductivity measurements in the study of ion interaction with proteins, the binding of Na, K, Ca, and Mg by human serum albumin was investigated.

The measurements were carried out with albumin solutions which were defined by a constant negative net charge of 36 units per albumin molecule, corresponding to a mean pH value of 7.5.

No or little binding of Na and K by this protein was found. Ca and Mg were bound to a maximum of about 8 ions per albumin molecule. This maximum corresponds to only a fraction of the net initial charge. The results are in agreement with those of other workers.

The method proved to be of value for simple, well‐defined systems and has the advantage that all the difficulties encountered in the use of membranes and potential measurements are avoided.

Moreover, it may be used when only small amounts of protein are available.
Preparation of quinazoline derivatives through ring‐closure of aromatic ortho‐cyano‐acylamino compounds in alkaline alcoholic or phenolic medium. I. 4‐RO‐substituted quinazolines
Authors: Breukink K. W. , Krol L. H. , Verkade P. E. , Wepster B. M.
Published: September 2010

On boiling aromatic ortho‐cyano‐acylamino compounds in alkaline alcoholic or phenolic solution ‐ medium ROH ‐ 4‐RO‐substituted quinazolines are formed. Some examples of this reaction are described.
Chemistry of acetylenic ethers XXV: Reactions of ethoxyacetylene with aqueous solutions of aliphatic aldehydes
Authors: Vieregge H. , Arens J. F.
Published: September 2010

On shaking ethoxyacetylene (IV) with aqueous solutions of aliphatic aldehydes at room temperature, β‐hydroxy‐esters (V) are obtained, in some cases together with small amounts of the corresponding α,β‐unsaturated esters (VI).
The infra‐red absorption spectra of some salts of dimethyl, diethyl, and diisopropyl phosphate
Authors: Maarsen J. W. , Smit M. C.
Published: September 2010

The infra‐red absorption spectra of some salts of (H3CO)2PO2−, (H5C2O)2PO2−, and (i H7C3O)2PO2−have been investigated.

From the spectra of the cyclohexylammonium salts, which give relatively simple spectra in CCl4and CS2solutions, an unambiguous interpretation of the PO2(ionic) stretching frequencies could be given.
Vapour‐liquid equilibria: System Acetone(1)‐benzene(2)‐cyclohexane(3)
Authors: Kurmanadharao K. V. , Krishnamurty V. V. G. , Venkatarao C.
Published: September 2010

Vapour‐liquid equilibrium data of the ternary system acetone‐benzene‐cyclohexane have been determined at 760 mm Hg pressure, using a modified Colburn still. No ternary azeotrope has been observed in this system.

The experimental data are found to be thermodynamically consistent according to the method proposed by Krishnamurty and Venkatarao for testing data on ternary and multi‐component systems.

The activity coefficient data of the present system have been satisfactorily correlated by the ternary modified Margules expressions with Ct = 0.7. The smoothed experimental data are in close agreement with the T‐x‐y data calculated by using the 3‐suffix modified Margules equations with the above ternary constant.

The present system is of considerable interest, since all the binary systems show positive deviations and such systems are more generally met with industrially in connection with extractive distillation processes. Further, in the present ternary system, two of the binary sub‐systems form minimum boiling azeotropes.
Reaction of pyridine carboxylic esters with sodium borohydride
Authors: Bigot J. A. , de Boer Th. J. , Sixma F. L. J.
Published: September 2010

Esters of nicotinic and isonicotinic acids are reduced to the alcohols by sodium borohydride in the presence of aluminium chloride, with difficulty. Ethyl isonicotinate easily forms a stable borine (BH3) complex, obtainable in 80% yield.
The reaction of α‐methylstyrene with formaldehyde
Authors: Beets M. G. J. , van Essen H.
Published: September 2010

By reacting α‐methylstyrene with formaldehyde in the presence of catalytic amounts of mineral acid, 4‐methyl‐4‐phenyl‐m‐dioxan is obtained in high yield. At higher acid concentrations and in the presence of a large excess of formaldehyde, however, a series of secondary reactions occur, all characterized by the formation of a double bond followed by further condensation with formaldehyde and, where possible, cyclization by formation of m‐dioxan or tetrahydropyran rings. These reactions have been studied, a number of reaction products have been isolated and their structures have been established.

Also in the case of styrene an extremely slow secondary reaction of the same type could be realized and its products have been studied. The mechanism of these reactions is discussed.
Substitution reactions in the pyridine nucleus at elevated temperatures (I). The bromination of 2,6‐dibromopyridine
Authors: Den Hertog H. J. , Combé W. P. , Kolder C. R.
Published: September 2010

The bromination of 2.6‐dibromopyridine between 450° and 550° has been investigated.

Two types of substitution reactions have been observed. When a mixture of 2,6‐dibromopyridine and bromine is passed over an iron bromide‐ or copper bromide‐pumice contact the 3‐ and 5‐hydrogen atoms are replaced by bromine. In an empty tube or a tube packed with pumice firstly the 4‐hydrogen atom is substituted by bromine, 2,4,6‐tribromopyridine being formed. The last mentioned reaction is slow. At 450°, with a contact time of about 3 minutes and a ratio dibromopyridine: bromine = 1:1.3, only 3% of 2,6‐dibromopyridine is converted. The reaction rate rises quickly when the temperature is increased; at 530° under corresponding conditions 35‐40% of the starting substance reacts.
Photochlorination of butyryl, valeryl and caproyl chloride
Authors: Smit P. , Den Hertog H. J.
Published: September 2010

The photochlorination at room temperature of butyryl, valeryl and caproyl chloride in the liquid phase has been investigated.

The acid chlorides were allowed to interact with a third of the equimolecular amount of chlorine under irradiation with a mercury lamp. The reaction mixtures obtained were separated by fractional distillation and counter current distribution according to Craig.

The monochloro‐derivatives of the acid chlorides were characterized by preparing the ρ‐toluidides. The identity of α‐, β‐, δ‐ and ϵ‐chlorocaproic acids was established by synthesis.

It is found that butyryl chloride yields <2% α‐, 50‐55% β‐ and 45‐50% γ‐chlorobutyryl chloride; valeryl chloride yields <1.5% α‐, 15‐20% β‐, 50‐55% γ‐ and 30‐35% δ‐chlorovaleryl chloride, while caproyl chloride produces < 1 % α‐, 5‐10% β‐, 25‐30% γ‐, 40‐45% δ‐and 20‐25% ϵ‐chlorocaproyl chloride.

These results can be explained by reckoning with the fact that secondary hydrogen atoms are replaced more rapidly than primary and taking into account the deactivating effect of the carbonyl chloride group along the chain.
The vibrational spectra of the methane‐phosphonate and the dimethylphosphinate ion
Authors: Gerding H. , Maarsen J. W. , Zijp D. H.
Published: September 2010

From the Raman spectra of H3CPO32− and (H3C)2PO2− the PO force constants have been calculated for the simplified models CPO32− and C2PO2−, thus neglecting the hydrogen atoms. A steady increase in PO stretching force constant has been found in the sequence PO43− to X3PO.

The spectra of the corresponding acids have been interpreted as far as possible.
The Raman and infra‐red spectra of methane‐sulphonic acid and the methanesulphonate ion
Authors: Gerding H. , Maarsen J. W.
Published: September 2010

The Raman and infra‐red spectra of H3CSO3H and some of its salts have been obtained, with Raman polarization data for the acid.

An interpretation of the spectra is given and force constants have been calculated.
The kinetics of the oxidation of 2,4‐dimethylphloroglucinol
Authors: Stein H. N. , Tendeloo H. J. C.
Published: September 2010

Following previous researches on the oxidation of phloroglucinol

H. N. Stein and H. J. C. Tendeloo, Rec. trav. chim. 74, 905 (1955).

)

Idem, ibid. 75, 1233 (1956).

)

Idem, ibid. 75, 1240 (1956).

), we investigated the kinetics of the oxidation of 2.4‐dimethylphloroglucinol by K3Fe(CN)6. Our aim was to examine whether this oxidation could be described by the same mechanism as was found with phloroglucinol itself

H. N. Stein and H. J. C. Tendeloo, Rec. trav. chim. 74, 905 (1955).

). magnified image

In addition, we wanted to obtain some data for a more detailed insight into this mechanism, as was done by Weissberger et al.

J. E. Lu Valle and A. Weissberger, J. Am. Chem. Soc. 69, 1567 (1947)

)

Idem, ibid. 69, 1576 (1947).

)

Idem, ibid. 69, 1821 (1947).

) in the case of derivatives of hydroquinone.
Oxidation potentials of conjugated hydrocarbons
Authors: Hoijtink G. J.
Published: September 2010

A linear relationship is found when the oxidation potentials of various aromatic hydrocarbons are plotted against the root of the Hückel secular equation corresponding to the highest occupied π‐orbital. In accordance with theory a straight line is also obtained by plotting the oxidation potentials of alternant hydrocarbons against the reduction potentials. The oxidation and reduction potentials of the non‐alternant hydrocarbon fluoranthene do not satisfy this condition.
Steric effects on mesomerism: XVIII). Steric inhibition of the mesomerism in aromatic amines with bulky N‐alkyl groups of compact structure: Nitrosation and coupling of the four N‐methyl‐N‐butylanilines
Authors: van Hoek T. C. , Verkade P. E. , Wepster B. M.
Published: September 2010

Nitrosation and coupling experiments with the four N‐methyl‐N‐butyl‐anilines are described. N‐methyl‐N‐tert.butylaniline cannot be nitrosated and reacts only very slowly with actively coupling diazonium salts.
Phosphatide acids and derivatives. VIII). Synthesis of monobenzyl esters of phosphatidic acids
Authors: Gielkens J. W. , Hoefnagel M. A. , Stegerhoek L. J. , Verkade P. E.
Published: September 2010

The preparation of dibenzyl esters of phosphatidic acids and their mono‐debenzylation by boiling with anhydrous sodium iodide in acetone solution is described.
Fries rearrangement of o‐chlorophenyl and o‐tolyl arene‐sulphonates
Authors: Baliah V. , Uma M.
Published: September 2010

o‐Chlorophenyl benzenesulphonate, o‐chlorophenyl p‐toluenesulphonate, o‐tolyl benzenesulphonate and o‐tolyl p‐toluenesulphonate undergo the Fries rearrangement when heated with anhydrous aluminium chloride, to furnish, In each case, a mixture of o‐ and p‐hydroxy‐sulphones. The structures of all the sulphones, thus obtained, have been established by synthesizing them unequivocally.
Nitration with acids consisting of HNO3 and SO3
Authors: Heertjes P. M.
Published: September 2010

The nitrating potentialities of mixed acids consisting of HNO3 and SO3 as compared with mixed acids of HNO3 and H2SO4 have been investigated on three examples, viz the easy nitration of p‐chloronitrobenzene to chloro‐2:4‐dinitrobenzene, the difficult nitration of this compound to chloro‐2:4:6‐nitrobenzene and the relatively easy nitration of 2:4‐dinitrotoluene to 2:4:6‐trinitrotoluene in which oxidation can be rather marked. The experiments have been carried out batch‐wise and continuously.

From the experiments it could be concluded that the HNO3‐SO3 acids with an SO3 content between 40 and 72% SO3 are good nitrating acids. For difficult nitration the use of acid with ∼70% SO3 shows a definite advantage over acids of HNO3 and H2SO4. For the acids containing ∼45% of SO3, which in view of their thermal stability can only be used for relatively easy nitrations, the difference between the two types of acids is not very large. However, the advantage of the better SO3‐economy with the HNO3‐SO3 acids is always present.
Investigations on pyrazine derivatives III: The preparation of 2,3‐dihydroxypyrazine 5,6‐dicarboxylic acid
Authors: Mager H. I. X. , Berends W.
Published: September 2010

By following the oxidation of a quinoxaline derivative spectrophotometrically, it has been possible for the first time to work out a simple preparative method for a hydroxylated pyrazine 2,3‐dicarboxylic acid.
The reactivity of pyridine towards sulphuric acid at elevated temperatures
Authors: Den Hertog H. J. , van der Plas H. C. , Buurman D. J.
Published: September 2010

When pyridine is heated with 100% sulphuric acid in the presence of mercuric sulphate as a catalyst at about 275°, pyridine‐3‐sulphonic acid is formed as the chief product, together with very small amounts of byproducts.

The course of the reaction is more complicated at somewhat higher reaction temperatures. At 330° a mixture is obtained which contains, together with pyridine‐3‐sulphonic acid and the 4‐isomer, 4‐hydroxypyridine in considerable amount.

The sulphonation of pyridine is a reversible process. When pyridine‐3‐sulphonic acid is heated with 100% sulphuric acid and mercuric sulphate at ∼ 330°, a mixture is formed containing chiefly pyridine, together with pyridine‐4‐sulphonic acid, 4‐hydroxypyridine and the starting substance.
Chemical studies on insecticides VII : Dipole moments of some esters of phosphoric and phosphorothioic acid
Authors: Ketelaar J. A. A. , Gersmann H. R. , Hartog F.
Published: September 2010

In order to compare the partial bond moments of “energy rich” and other phosphorus acid esters dipole moments of a number of esters have been determined from dielectric constant measurements.

Literature values of dipole moments of phosphorus acid derivatives are also presented.
Investigations on nematicides: I. Isolation and structure of a nematicidal principe occurring in Tagetes roots
Authors: Uhlenbroek J. H. , Bijloo J. D.
Published: September 2010

Some highly nematicidal polythienyls have been isolated from the roots of Tagetes plants. One of the compounds was shown to be α‐terthienyl (I).
Some remarks on the relative antifungal activities of N‐substituted dithiocarbamates: (Short communication)
Authors: Links J.
Published: September 2010

A hypothesis, that explains the relative antifungal activities of the lower N‐substituted dithiocarbamates (and the relative plant growth regulating properties of some of them) by hyperconjugation, is critically discussed and an alternative, tentative explanation is given.
Aldol condensations with butanone
Authors: Beets M. G. J. , van Essen H.
Published: September 2010

A new method for the aldol condensation of citral with butanone is described by which the condensation takes place mainly at the methylene group of the ketone. The mechanism of the reaction is discussed.
The Copper‐rich part of the copper‐barium system
Authors: Braun P. B. , Meijering J. L.
Published: September 2010

The system Cu‐Ba was examined up to 75% Ba by weight. At 675° C there is a peritectic three‐phase equilibrium Cu + liquid ⇋ Cu13Ba. The compound Cu13Ba has KZn13 structure. At 550° C there is a eutectic three‐phase equilibrium liquid ⇋ Cu13Ba + CuxBay. Composition and structure of the latter could not be determined owing to experimental difficulties.
The preparation of some alkyl p‐nitrophenyl methylphosphonates
Authors: de Roos A. M.
Published: September 2010

The lower homologues in the series of the alkyl p‐nitrophenyl methyl‐phosphonates have been prepared by reaction between p‐nitrophenyl methylphosphonochloridate and an alcohol. Some alkyl methylphosphonochloridates have also been synthesized, starting from methylphosphonic dichloride. Boiling points and refractive indices of the yellow p‐nitrophenyl compounds and of the colourless chloridates have been recorded, as well as the infrared spectrum of iso‐butyl p‐nitrophenyl methylphosphonate.
The ozonolysis of phenanthrene)
Authors: Wibaut J. P. , de Boer Th. J.
Published: September 2010

Phenanthrene reacts quickly with one mole of ozone at the 9,10‐double bond. In chloroform a polymeric mono‐ozonide (II) is obtained, which can be converted into diphenic acid. In methanol the reaction takes a different course resulting in the formation of a cyclic methoxy‐hydroxy‐peroxide (V) and a cyclic dimethoxy‐peroxide (VI).
An improved method for the preparation of DL 4‐oxalysine
Authors: Tesser G. I. , Nefkens G. H. L.
Published: September 2010

An improved synthesis of DL 4‐oxalysine is described, with reference to the reactions outlined in the flow‐sheet.
The vapour pressure of tungsten trioxide in gas mixtures containing water vapour
Authors: Meyer G. , Oosterom J. F. , van Oeveren W. J.
Published: September 2010

The increased volatility of tungsten trioxide in an inert atmosphere containing water vapour, must be ascribed to the formation of a volatile compound.

The composition of this compound is probably WO31H2O. The equilibrium between solid WO3, water vapour and gaseous compound shifts as the temperature is increased towards the formation of the compound. Thus on lowering the temperature the compound will break down again into anhydrous oxide and water.

Hence this compound has the same empirical composition as tungstic acid (H2WO4). Experiments in this laboratory have shown that solid tungstic acid passes over into the anhydrous oxide at ∼ 180° and a pressure of 10 atmospheres (quadruple point WO31H2O ‐ WO3‐L ‐G). At the temperatures at which our investigation has been carried out therefore, the assumption that the gaseous compound can exist also in the solid state, must be regarded as improbable.
The fries rearrangement of 1‐naphthyl acetate
Authors: Cullinane N. M. , Bailey‐Wood V. V.
Published: September 2010

The rearrangement of 1‐naphthyl acetate in nitrobenzene solution, catalysed by aluminium chloride, to give 2‐ and 4‐acetylnaphthol, appears to be intramolecular in nature. A mechanism to account for the experimental results is proposed. While the main product is the p‐hydroxy‐ketone, moderate yields of the ortho‐substituted product are also obtained.
The formation of diacetyl and acetoin from α‐acetolactic acid
Authors: de Man J. C.
Published: September 2010

Of several ions tested, only Fe+3, Cu+2 and Al+3 catalysed the decarboxylation of α‐acetolactic acid at pH 4.8.

At pH 2.2, only Fe+3 and Cu+2 were active.

Fe+3 and Cu+2 were shown to form complexes with α‐acetolactic acid.

Fe+3 and Cu+2 not only decarboxylated but also oxidized α‐acetolactic acid, with, as a result, formation of diacetyl.

Decarboxylation of α‐acetolactic acid by these ions is compatible with the mechanism suggested by Martell and Calvin.

α‐Acetolactic acid is subject to autoxidation. 2‐Butene‐2,3‐diol may be an intermediate product.
Studies on polarographic maxima. Part I. Concentration of the maximum suppressor in relation to its lowering of the interfacial tension
Authors: Khalafalla S. E. , el Din A. M. Shams , Marei S. A.
Published: September 2010

Polarographic maxima have been studied in the light of the electrocapillary curves produced by the successive addition of the maximum suppressor. An interesting agreement has been noticed between the minimum concentration of the suppressor required to eliminate the polarographic maximum completely and the point of greatest negative slope in the interfacial‐tension concentration curve. The results show that polarographic maxima are eliminated when the adsorption of the maximum suppressor on the mercury‐solution interface reaches its maximum value.
Les Arènesulfonylsulfates Méthyliques, Intermediaires D'Une Synthese des Sulfones Aromatiques
Authors: Joly Robert , Bucourt Robert , Mathieu Jean
Published: September 2010

Les arènesulfonylsulfates de méthyle sont obtenus soit par addition d'anhydride sulfurique sur la molécule d'un arènesulfonate de méthyle, soit par dismutation entre un acide arènesulfonique et le pyrosulfate de méthyle. Ces nouveaux dérivés réagissent aisément avec des composés aromatiques pour conduire aux sulfones, symétriques ou non, avec des rendements élevés.
The chlorination of 4‐aminobenzoic acid and its methyl ester
Authors: van der Stelt C. , Nauta W. Th.
Published: September 2010

Chlorination of 4‐acetylaminobenzoic acid (III) afforded 4‐acetylamino‐3,5‐dichlorobenzoic acid (IV, m.p. 237‐238°), which could be saponified easily to 4‐amino‐3,5‐dichlorobenzoic acid (II, m.p. 290°). Direct chlorination of 4‐aminobenzoic acid (I) in a mixture of glacial acetic acid and hydrochloric acid afforded 3,4,4,6,6‐pentachloro‐1‐cyclohexen‐5‐one‐2‐carboxylic acid (V, m.p. 178‐180°), a compound already obtained by Zincke by the chlorination of 4‐hydroxybenzoic acid (VI). Compounds with a higher content of chlorine could be prepared by the chlorination of the methyl ester of I (VIII). The reaction carried out in a neutral medium led to the nitrogen containing compound IX with m.p. 151‐153° and gross formula C8H5NO2Cl8 to which the structure of a methyl 1,2,3,3,5,5,6‐heptachloro‐4‐chloriminocyclohexane‐1‐carboxylate was attributed. Reduction with stannous chloride converted IX into methyl 4‐amino‐3,5‐dichlorobenzoate (X), which can be used as a starting product for IX. Chlorination of VIII in a mixture of glacial acetic acid and hydrochloric acid yielded a compound XI with m.p. 129‐131° and gross formula C8H5O3Cl7 as the main reaction product to which the structure of a methyl 1,2,3,3,5,5,6‐heptachlorocyclohexan‐4‐one‐1‐carboxylate has been attributed. Acid hydrolysis converted IX into XI. From the same reaction mixture two other stereo‐isomers of XI also were isolated, be it in minor quantities (XII m.p. 140–142°, XIII m.p. 213‐215°). The stereoisomerism of the three compounds is caused by the different spatial arrangement of the chlorine atoms attached to carbon atoms 1, 2 and 6. Reduction converted the three isomers into methyl 3,5‐dichloro‐4‐hydroxybenzoate (XIV). Chlorination of the methyl esters of VI and XIV also afforded amounts of XI. A fourth chlorination product could be isolated from the reaction mixture of VIII, viz. a compound with m.p. 199‐200° and gross formula C8H6O4Cl6 (XVI). Reduction with stannous chloride converted it into a compound XVII with m.p. 121‐122° and gross formula C8H8O4Cl2. Both compounds contain an extra hydroxyl group. Lack of material prevented further establishment of the structure. The infrared spectra of a number of polychloro‐compounds are given.
Chemistry of acetylenic ethers XXXVII. Synthesis of β‐lactams (2‐azetidinones) from imines and ethoxyalkynes
Authors: van Leusen A. M. , Arens J. F.
Published: September 2010

β‐Lactams VII are formed when ethoxyalkynes II are slowly added to boiling solutions of aromatic imines VI in xylene. In all probability aldoketenes III are intermediate products. The yields are moderate to good.
Derivatives of amino‐acids and peptides V. Complex formation of benzyloxycarbonylamino‐acids with their salts
Authors: Grommers E. P. , Arens J. F.
Published: September 2010

Benzyloxycarbonylamino‐acids and ‐peptides very easily form addition compounds with their alkali metal salts; this sometimes causes difficulties during the preparation of benzyloxycarbonylamino‐acids or ‐peptides. The complexes may separate in crystalline form when aqueous solutions of the salts are acidified; they can also be prepared by mixing solutions of the free benzyloxycarbonyl derivatives with solutions of appropriate amounts of the salts. Some complexes are oily and fairly soluble in ethyl acetate. From one set of components (Cbo‐amino‐acid and its salt) sometimes more than one type of complex can be obtained each having a characteristic melting point. The solvent used for the crystallisation largely defines the complex. Within one type the salt content can vary. It seems that within certain limits an arbitrary number of metal ions can replace protons of COOH groups.
Determination of equilibrium constants for a number of metal‐phosphate complexes
Authors: Wolhoff J. A. , Overbeek J. Th. G.
Published: September 2010

Many metal ions form soluble complexes with pyro‐ and tripolyphosphate. Complex formation entails a decrease in pH. By measuring the pH and in some cases the concentration of free metal ions, equilibrium constants for a number of metal‐phosphate complexes were determined at 25° and at 40°. Activity corrections were applied. The tendency to form complexes increases in the following order:

Tripolyphosphate has somewhat stronger complexing properties than pyrophosphate. The influence of the temperature is in most cases small. Constants obtained are listed in Table V.
A cryoscopic study of the behaviour of s‐trinitrobenzene and some other organic compounds in ethanolamine
Authors: Baliah V. , Ramakrishnan V.
Published: September 2010

The behaviour in ethanolamine of some aromatic polynitro compounds and compounds containing active methylene groups has been studied cryoscopically. It is suggested that s‐trinitrobenzene, s‐trinitro‐t‐butylbenzene, and picramide ionise by the proton‐transfer mechanism. s‐Trinitroanisole, besides exhibiting a similar behaviour, undergoes a solvolytic reaction, the methoxyl group being replaced by NH.CH2CH2OH. Picric acid ionises as (NO2)3C6H2OH → (NO2)3C6H2O− + H+. Diethyl malonate, ethyl acetoacetate, and acetylacetone undergo solvolysis. Bis(phenylsulphonyl)methane ionises by the proton‐transfer mechanism.
Chemistry of acetylenic ethers XXXIX: Reactions of acetylenic ethers with carbonyl compounds in aqueous solution
Authors: Vieregge H. , Arens J. F.
Published: September 2010

Acetylenic ethers V react with aldehydes in aqueous medium at room temperature to yield the hydroxy esters VII and IX, often together with a small amount of the unsaturated ester VIII. The acetylenic ethers do not react in such a way with ketones and aromatic aldehydes but a similar reaction occurs with ethyl mesoxalate.
Chemistry of acetylenic ethers XL: Rearrangement during the conversion of ethoxyethyne with butynedioic acid
Authors: Cley J. , Arens J. F.
Published: September 2010

Ethoxyethyne I readily reacted with an ethereal solution of butynedioic acid V affording a product, C12H16O7, obviously formed from 1 mole of butynedioic acid, two moles of ethoxyethyne and one mole of water. Further investigations revealed that it had the anhydride structure IX. By performing the conversion in alcohol, tetraethyl DL‐butane‐1,2,3,4‐tetra‐carboxylate X, was obtained.

The reactions probably involved a rearrangement as pictured in the scheme on page 931 and thus proceeded via the bis‐ketene VIII.

From phenylpropiolic acid and ethoxyethyne the anhydride XI of 1‐phenylnaphthalene‐2,3‐dicarboxylic acid was obtained in low yield. Tetrolic acid was converted into its anhydride in high yield.
Nucleophilic aromatic addition: I. The reaction of diazomethane with 1,3,5‐trinitrobenzene
Authors: de Boer Th. J. , van Velzen J. C.
Published: September 2010

The structure of the reaction product from 1,3,5‐trinitrobenzene and an excess (i.e. at least four moles) of diazomethane, as found many years ago by Heinke, is shown to be a seven‐membered ring‐compound condensed with two cyclopropane rings and with one pyrazoline ring (VII). If 1,3,5‐trinitrobenzene is treated with diazomethane in a molar ratio of 1:3, no pyrazoline derivative is formed, but a hitherto unknown “tris‐methylene” derivative (VI), containing a seven‐membered ring system condensed with two cyclopropane rings. This remarkably stable compound is an intermediate in the reaction with excess of diazomethane. When the molar ratio of the reactants is reduced to 1 : 2 or 1 : 1, the “trismethylene” derivative (VI) results, together with unchanged 1,3,5‐trinitrobenzene.
The preparation of pure silicon
Authors: van der Linden P. C. , de Jonge J.
Published: September 2010

An apparatus is described for the preparation of pure silicon by thermal decomposition of trichlorosilane on a hot tantalum wire in a hydrogen atmosphere. The polycrystalline silicon is obtained in the form of rods with a diameter of about 15 mm and a length of 20‐40 cm. The yield of Si is 45‐50 % if calculated on the Si‐content of SiHCl3. From resistivity measurements, the boron content of the silicon obtained can be calculated to be 0.5 × 10−6% (resistivity of single crystals about 300–500 ohm‐cm p‐type).
Kinetics and mechanism of the cyclic‐hemiacetal ring opening in 2‐keto‐L‐gulonic acid. A polarographic study
Authors: Los J. M. , Gaspar N. J.
Published: September 2010

The occurrence of two consecutive cathodic waves, both with absolute rate control, in the case of the polarographic reduction of 2‐keto‐L‐gulonic acid in a buffer solution of malonic acid (pH between 4.8 and 6.3) is described. The theory of this case is based on the assumption that 2‐keto‐gulonic acid or its anion predominantly exists in the cyclic‐hemiacetal form, which is non‐reducible, but which produces the free keto‐acid or its anion by a very rapid reaction in the zone around the dropping mercury electrode. The latter substances are reducible, with different half wave potentials. Expressions in the relevant rate constants are derived for both the total current and the current of the first wave. This does not permit the calculation of all the rate constants involved. However, it could be shown that the wave heights are related to pH in the way predicted by the theory. Definite conclusions with respect to the relative magnitude of the rate constants could be drawn. The single wave in the lower pH range of 0.2 to 3.5 was also studied as a function of pH. The reaction mechanism is discussed on the basis of the relationships found and in connection with the expected influence of the ionization of the carboxyl group upon the reactivity of the catalytic species present. The process of ring closure or opening was shown to be second‐order, rather than third.
Migration of an acyl group in glycerol derivatives: I. Migration of the acyl group in monoglycerides in acid medium
Authors: van Lohuizen O. E. , Verkade P. E.
Published: September 2010

For a number of pairs of isomeric α‐ and β‐monoglycerides with a carboxylic acid as component acid it is shown that these isomers mutually rearrange in ethanolic hydrogen chloride. At 25° the equilibrium mixture invariably contains about 88% of α‐ and consequently about 12% of β‐monoglyceride.

From measurements of the migration rate of β‐monobenzoylglycerol in the said medium at 25° it appeared that the migration reaction shows kinetics of the first order and that the migration rate is directly proportional to the concentration of the catalyst. Addition of small quantities of water to the medium retards the migration reaction to a very great extent.

The determination of α‐monoglyceride in mixtures of α‐ and β‐monoglyceride was effected by periodic‐acid oxidation, as described previously.

The migration rate constant of a number of β‐monoglycerides was determined under identical experimental conditions. The nature of the acyl group has great influence on the migration rate, but not ‐ see above – on the position of the equilibrium.

The mechanism of this intramolecular rearrangement of the monoglycerides is discussed and used for an explanation of the facts observed.

Monoglycerides with a sulphonic acid as component acid do not show any tendency towards rearrangement under the same experimental conditions.
Spectrophotometric investigations of the mechanism of complex formation: Part I: General description of the technique
Authors: Adema E. H. , Visser R. , Sixma F. L. J.
Published: September 2010

A description is given of a cell used in taking ultraviolet spectra, especially at lower temperatures, and of a cryostat which can be kept constant within 0.02° down to −150°. Whilst the spectra are being taken, the concentration can be increased by means of a microburette, with exclusion of moisture and oxygen. Thus rates of formation and positions of equilibria of unstable systems can be determined.
Reactions between acids and thiourea: Part I. The formation of amides from acids and thiourea
Authors: Rahman Aziz‐Ur , Medrano Miguel A. , Mittal O. P.
Published: September 2010

A method for the preparation of acid amides by heating an equimolecular mixture of acid and thiourea, is described. The method has been successfully applied to aliphatic mono‐ and di‐basic acids, aryl‐aliphatic acids as well as benzoic acid. The yield has been found to be dependent upon the relative volatility of the acid employed for the reaction. Best yields have been obtained with aryl‐aliphatic acids. The mechanism of amide formation from acid and thiourea, based upon the intermediate addition of carboxylic acid to thiocyanic acid, the latter formed by the decomposition of thiourea, is suggested and an electronic representation of the mechanism is given.
The position of the glucose unit in synthesized rhein monoglucoside
Authors: Bellaart A. C. , Koningsberger C.
Published: September 2010

It is shown that in synthesized rhein monoglucoside the glucose unit is located at position 1 of 1,8‐dihydroxyanthraquinone‐3‐carboxylic acid.
Precipitate impregnated membranes: I. Some properties of the BaSO4‐cellophane membrane
Authors: Hirsch‐Ayalon P.
Published: September 2010

Washed‐out BaSO4‐cellophane membranes have been analysed. The number and strength of acid groups in them are the same as in the original cellophane. Membrane diffusion potentials arising with different electrolytes at washed BaSO4 membranes have been measured in the usual way and found to be the same as with original cellophane. Direct examination of the permeability of effective BaSO4 membranes to Ba and SO4 ions in a special case (viz. our “standard experiment”) confirmed that this permeability is extremely low, amounting practically to impermeability in this case. This property, as well as the characteristic membrane potentials at the effective BaSO4 membrane depend on the simultaneous presence of Ba and SO4 ions in the adjacent solutions. The special behaviour of the effective BaSO4 membrane is not due to “fixed charges” in the usual sense.
Investigations on sterols XIV studies on vitamin D and related compounds XII the photoisomerization of lumisterol2
Authors: Rappoldt M. P.
Published: September 2010

Kinetic experiments on the isomerization of lumisterol2 under the influence of ultraviolet light of various wavelengths are reported. The experiments indicate that neither tachysterol2 nor ergosterol are primary reaction products of lumisterol2. Lumisterol2 is exclusively converted into pre‐ergocalciferol. The quantum yield of this reaction is 0.41 at 2537 Å.
Studies in IVth group organometallic chemistry. V: Preparation of some p‐styrenyl‐substituted derivatives of germanium, tin and lead
Authors: Noltes J. G. , Budding H. A. , van der Kerk G. J. M.
Published: September 2010

The preparation of triphenylmono‐ and diphenyldi‐p‐styrenyl derivatives of germanium, tin and lead is described. The infra‐red spectra of these compounds are discussed.
The decomposition of organic hydroperoxides: Part III. Kinetics of the acid‐catalyzed decomposition of benzyl‐type hydroperoxides
Authors: de Ruyter van Steveninck A. W. , Kooyman E. C.
Published: September 2010

The HClO4‐catalyzed decomposition of a number of alkylbenzyl hydroperoxides has been investigated by a study of the reaction kinetics in 50% w ethanol at 50°C. A Hammett relation (p = ‐4.57) has been found to exist for the decomposition of ring‐substituted α,α‐dimethylbenzyl hydroperoxides to the corresponding phenols and acetone, σ+ values giving the best correlation. An electrolyte effect has been observed in the decomposition of the hydroperoxides studied, the magnitude of which runs parallel to the reactivity of the various hydroperoxides. A qualitative explanation of this phenomenon can be given in terms of differences in solvation for the different transition state complexes. Data for the enthalpy and entropy of activation are in accordance with this assumption. Our results provide further support for the recently proposed mechanism of the acid‐catalyzed hydroperoxide decomposition. The effect of nuclear substituents and the observation of the electrolyte effect permit of a detailed description of the transition state complex. In the acid‐catalyzed decomposition of some substituted alkylbenzyl hydroperoxides other reactions have been encountered, which are discussed briefly.
Preparation of quinazoline derivatives through ring closure of aromatic ortho‐cyano‐acylamino compounds in alkaline alcoholic or phenolic medium II
Authors: Breukink K. W. , Verkade P. E.
Published: September 2010

Some new quinazoline derivatives were prepared by boiling the appropriate ortho‐cyano‐acylaminobenzene in alkaline alcoholic medium. Proofs of the constitution of the quinazoline derivatives are given.
An extraction procedure for the colorimetric determination of silica
Authors: Wilson H. N. , Skinner J. M.
Published: September 2010

Tri‐isodecylamine is proposed as a versatile reagent for extracting inorganic anions from aqueous solution: its use in the determination of silica is described. The advantages of a non‐aqueous extraction method are discussed and full instructions given for the determination of silica in anhydrite and the like.
Gas hydrates of nitrogen and oxygen
Authors: van Cleeff A. , Diepen G. A. M.
Published: September 2010

Gas hydrates of nitrogen and oxygen are described.

P ‐ t relations of the three‐phase equilibria in the system nitrogen ‐ water are given from ‐ 4 to 18°C at pressures up to 1000atm. The dissociation pressure of oxygen hydrate is given at 0°C.
Spectrophometric acid‐base titrations with the use of indicators
Authors: Karsten P. , Kies H. L. , de Hoog P.
Published: September 2010

The accuracy of acid‐base titrations in aqueous and non‐aqueous media can be considerably improved by making use of a spectrophotometric with the addition of indication
Olefinic unsaturation of styrenated linseed oils
Authors: Tiong Sie Swan , Waterman H. I.
Published: September 2010

The olefinic unsaturation of styrenated linseed oils has been determined by quantitative ozonolysis. Products obtained by reaction of gaseous styrene with linseed oil under various conditions have been examined and are characterized by means of a diagram in which the relative decrease in unsaturation is plotted against the relative decrease in saponification value.

From the data obtained it can be concluded that two types of reactions are mainly responsible for the conversion of styrene, viz. the formation of styrene polymers and copolymerization involving the double bonds of the fatty‐acid residues. Copolymerization of linseed oil with styrene does not take place to an appreciable extent at temperatures below 200°. At 280°, however, practically no high‐molecular‐weight polystyrene is formed and the take‐up of styrene is mainly due to copolymerization.
The degradation of toluene‐14C
Authors: Steinberg H. , Sixma F. L. J.
Published: September 2010

A method of degradation of toluene‐14C is described which makes it possible to determine the specific activity of each of the ring carbon atoms.
The pH of some standard solutions in methanol and methanol‐water mixtures at 25° I. Theoretical Part
Authors: de Ligny C. L. , Luykx P. F. M. , Rehbach M. , Wieneke A. A.
Published: September 2010

It has been shown that pH* values, determined by the electrometric method in solvents other than water, can be interpreted as ‐log mHγ*H if the pH meter is standardized by means of a standard solution in the same solvent. The pH* of standard solutions in methanol and methanol‐water mixtures can be determined by application of the same method as has been used by the National Bureau of Standards for the measurement of the pH of standard solutions in water.

The errors that may occur when the method of the N.B.S. is applied to standard solutions in solvents other than water have been discussed. In order to correct these errors we calculated, by the method of Fuoss and Onsager, the values of K and å for NaCl, KCl, KBr and KI in methanol, from literature data on the conductivity. The conductivity of solutions of NaBr and LiCl cannot be described satisfactorily by the equation of Fuoss and Onsager.