bluuebunny/crossref_metadata_2025_split huggingface dataset:
The external mass transfer of basic and acidic dyes on wood
Authors: McKay Gordon , McConvey Ian F. 
Published: July 2010

AbstractThe parameters affecting the initial adsorption rates of Astrazone Blue dye (Basic Blue 69) on to wood have been studied. A simple model has been proposed to determine the external mass transfer coefficients and these have been compared with values obtained using a more complex procedure. The external mass transfer coefficient, β, has been shown to vary linearly with agitation and initial dye concentration using log‐log coordinates; furthermore β is independent of particle size. The effect of temperature has been studied and the activation energy for the process is 44 ± 2 kJ mol−1. Similar correlations were obtained for the adsorption of Telon Blue dye (Acid Blue 25) on wood. Using log‐log correlations, the external mass transfer coefficient was found to vary with (rev min−1)0.14,C0−0.27; and a small dependence on particle size was also observed. The activation energy for the external mass transfer process was 25 ± 2 kJ mol−1.
Synthesis of 5‐hydroxymethyl‐2‐furancarboxaldehyde catalysed by cationic exchange resins. Part 2. Analysis and discussion of the effect of the main parameters on the HMF output
Authors: Mercadier Daniel , Rigal Luc , Gaset Antoine , Gorrichon Jean‐Pierre 
Published: July 2010

AbstractThe effects of the sugar and catalyst concentrations on the dehydration reaction of D‐fructose to 5‐hydroxymethyl‐2‐furancarboxaldehyde when a triphasic medium water‐solvent‐ion exchange resin is used, are described.
Development of a correlation between the non‐polar solubility parameter, refractive index and molecular structure. II. Aliphatic ethers and alcohols
Authors: Wingefors Stig 
Published: July 2010

AbstractA relationship between the non‐polar solubility parameter (λ) for polar aliphatic solvents and their refractive index has been developed. The use of structural group increments for branched isomers avoids the ambiguous choice between similarity in structure, reduced temperature and molal volume for the polar compound and its hydrocarbon homomorph. For straight‐chain compounds, where a direct comparison with λ as calculated from a homomorph correlation function is possible, the mean discrepancy in λ is 0.07% for ethers and 0.14% for alcohols at 25°C.
Analysis of multiple steady states of complex biochemical reactions
Authors: Ramachandran P. A. , Kulkarni B. D. , Sadana Ajit 
Published: July 2010

AbstractA general theory for the identification of criteria within which an enzymic reaction can exhibit multiplicity (i.e. multiple steady states) is reviewed. Application of the theory to four types of kinetic models encountered in biochemical reactions is illustrated and figures are presented to delineate the region of multiplicity. The stability of the steady states is analysed for small perturbation about the steady state.
Semiconductor‐electrochemical aspects of bacterial leaching. I. Oxidation of metal sulphides with large energy gaps
Authors: Tributsch Helmut , Bennett Josè C. 
Published: July 2010

AbstractThiobacillus ferrooxidanshas been cultivated successfully on synthetic metal sulphides with large energy gaps (CdS, ZnS) as the only energy source for many culture generations during a period of 4 years. The results obtained, which were quantitatively evaluated by calculations of electron transfer probabilities, show that a direct electron transfer from the metal sulphide valence band to the bacterial metabolic system (hole injection into the valence band of the sulphide) has to be excluded as the cause for the enhanced oxidative dissolution for energetic reasons. A detailed analysis of the dynamics of the metal sulphide aqueous electrolyte interface reveals that protons are involved in the mechanism on which bacterial activity is based. By reacting chemically with the metal sulphide surface they break chemical bonds and shift electronic states energetically into the forbidden energy gap to produce surface states which can be chemically described as −SH∂ groups. These control the rate of dissolution of the metal sulphide and are removed by bacterial activity. In this way the proton is recycled and its action can be considered catalytic. For sulphides in which the valence band of the semiconductor is derived from metal orbitals instead of from sulphur orbitals, this mechanism is bound to fail. MoS2and WS2are discussed as examples of such metal sulphides which are not a suitable energy source for bacteria. Some kinetic aspects of the bacterial surface reaction are discussed.
Liquid phase oxidation of p‐xylene to terephthalic acid by air in the absence of a promoter
Authors: Srivastava Krishna K. , Chandalia Sampatraj B. 
Published: July 2010

AbstractLiquid phase oxidation of p‐xylene to terephthalic acid by air in the presence of solvent acetic acid and a relatively large amount of cobalt acetate as catalyst has been investigated in the absence of any promoter at 100–130°C and a pressure of 2.5–10 kg cm−2. The effect of temperature, catalyst concentration, p‐xylene concentration, air flow rate, pressure, reaction period and addition of small amounts of zirconium salts, etc., on the conversion to terephthalic acid has been studied. p‐Toluic acid, which is an intermediate in the process, was the only major by‐product. The possibility of recycling the mother liquor after the separation of the product was ascertained.
Use of microbial enzyme and cell preparations to synthesise oligopeptide antibiotics
Authors: Vandamme Erick J. 
Published: July 2010

AbstractMicrobial enzymes and cells (in free or immobilised form) have so far been applied mainly in hydrolysis and bioconversion reactions, but recently there has been an increasing interest in the use of such ‘controlled catalytic biomass’ to produce fermentation products and to apply the principle to organic synthesis. Particular attention is given here to the use of immobilised enzymes and cells for producing known or new peptide antibiotics. An evaluation is presented of the applicability of this concept in the fascinating field of peptide antibiotic bioconversions and fermentations. As an important example of the use of enzymes or cells to convert peptide antibiotics into useful derivatives, free and immobilised penicillin acylases, producing the penicillin nucleus 6‐amino‐penicillanic acid, are reviewed as well as their potential to synthesise semi‐synthetic penicillins and cephalosporins. The action of acetylesterase and α‐amino acid ester hydrolase on cephalosporin compounds is also discussed. Use of enzymes and cells to synthesise antibiotics as an alternative method to conventional fermentation is subsequently reviewed. The concept of total enzymic synthesis in vitro of antibiotics is illustrated in the exploitation of the ‘multi‐enzyme thiotemplate mechanism’ of Bacillus brevis, to produce gramicidin S. Total synthesis of peptide antibiotics with immobilised living cells or mycelium as catalysts has been demonstrated recently in the cases of penicillin and bacitracin. These examples of complex multi‐step enzyme reactions might indicate the vast potential of immobilised enzyme and cell technology in fermentation, in biotechnological processes and in organic synthesis.
Preparation of aluminium hydroxide by reacting sodium aluminate solutions with mineral acid
Authors: Sato Taichi 
Published: July 2010

AbstractThe preparation of aluminium hydroxide from sodium aluminate solutions by varying the alkaline concentration at a fixed molar ratio of Na2O: Al2O3 has been investigated on addition of hydrochloric or nitric acids. The resulting materials have been examined by X‐ray diffraction study, infrared spectrophotometry, thermogravimetrical and differential analyses. As a result, it was found that precipitates generally exist as pseudoboehmite or bayerite, but the formation of bayerite is enhanced by a low rate of addition of acid, higher temperature or higher alkaline concentration. In this case, the composition of the precipitates was little influenced at different molar ratios of Na2O: Al2O3. When the precipitates from sodium aluminate solutions at low and higher alkali concentrations were aged in the mother liquors, pseudoboehmite therein transformed to hydrargillite and bayerite, respectively.
Homogeneous reduction of aromatic nitrocompounds by a triphenylphosphine complex of palladium
Authors: Banerjee Tapan Kr. , Sen Debrata 
Published: July 2010

AbstractThe complex Pd2(PPh3)2Cl4 has been used as a homogeneous catalyst for the reduction of C6H5NO2 and p‐ClC6H4NO2 in basic ethanol. A reaction intermediate [Pd(PPh3) (C6H5NO2)Cl2] has been isolated and characterised. Reduction of C6H5NO2 produced aniline (75%), azobenzene (5%) and azoxybenzene (15%) under conditions of atmospheric pressure, while under conditions of high pressure the reduction product contained aniline (95%) only. The yield of p‐ClC6H4NH2 was highest (75%) at normal pressure and decreased with increasing pressure.
Comparison of various methods to determine kinetic constants for β‐galactosidase in soluble and immobilised states
Authors: Peter J. , Prenosil J. E. , Bourne J. R. 
Published: July 2010

AbstractThe graphical methods of Lineweaver—Burk, Eadie, Hanes and the ‘direct linear plot’ have been used to determine the kinetic constants of β‐galactosidase in soluble and immobilised states. Because some of these methods require a reciprocal concentration scale, the activity values obtained from dilute substrate solutions are weighted more than when using more concentrated substrates. However, in the case of immobilised enzymes the values from dilute substrate are more affected by diffusion from the bulk solution into the pores where the enzyme is fixed, and vice versa. Therefore it, seems preferable to use methods with direct substrate and velocity scales. The direct linear plot method is recommended because it does not require any transformation of the measurements, the area of intersection points indicates the accuracy of the measurement and runaway points are easily detected.
Homogeneous hydroformylation of cyclohexene with bis(acetylacetonato)diaquo cobalt (II)
Authors: Banerjee Tapan K. , Saha Chitta R. , Sen Debabrata 
Published: July 2010

AbstractHydroformylation of cyclohexane by bis(acetylacetonato)diaquo cobalt(II) [Co(acac)2 (H2O)2] in benzene solution produced the corresponding aldehyde, alcohol and saturated hydrocarbon. The influence of various experimental conditions on the product distribution has been investigated and the optimum conditions for the maximum yield of aldehyde (45%) and alcohol (55%) have been established. A tentative mechanism for hydroformylation has been suggested on the basis of the isolated green complex [Co(acac)2]2(C6H10) having catalytic activity comparable with Co (acac)2(H2O)2 which has been isolated from the product mixture and also synthesised separately.
The preparation of pyrographite‐coated carbon paper by pyrolysis of methane on resistively heated cellulose‐based carbon paper
Authors: Attwood P. A. , Dixon A. G. , Houston A. C. , Short R. T. 
Published: July 2010

AbstractA laboratory technique has been developed for depositing a layer of pyrographite on to a cellulose‐based carbon‐fibre paper substrate by direct resistive heating in a methane/argon atmosphere, thereby enhancing its electrical conductivity and mechanical strength. The material can be used as a support for methanol electro‐oxidation catalysts and has proved to be a satisfactory replacement for a proprietary material which is no longer available.
The estimation of solubility parameters and related properties of liquids
Authors: McGowan John C. 
Published: July 2010

AbstractThe characteristic pressure, Px (=4.455×109 Nm−2), appears to be the same for all unassociated liquids, and the characteristic volume, Vx, may be found by the addition of atomic factors. The van der Waals constant a, latent heat of evaporation Δ1gHE and solubility parameter can all be estimated for such liquids, since a, Δ(Δ)gHE‐RT) V and δV equal Fx1/2Vx/3, where T is the temperature, R is the gas constant, and V=M/(∂L0‐∂g0): M is the molecular mass; ∂L0 is the density of the liquid and ∂g0 the vapour density. Molecular attraction constants used for the estimation of solubility parameters can be obtained by the multiplication of Vx by the constant Px1/2/3.
The effect of potassium and sodium sulphates on the reaction of synthetic anhydrite with water
Authors: Wilding Christopher R. , Mile Brynmor , Vincent Arthur T. 
Published: July 2010

AbstractStudies of the effects of the concentration of two additives K2SO4 and Na2SO4 on the hydration of synthetic anhydrite are presented which show the occurrence of broad optimisation maxima. By employing a novel in‐situ precipitation technique, substantial increases in the initial rate of hydration have been achieved.
A convenient preparative method for 2,4‐dialkyl‐2‐cycloalkenyl‐γ‐butyrolactones
Authors: Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi , Ishikame Keinosuke , Sugahara Kotoji 
Published: July 2010

AbstractSeveral, 2,4‐dialkyl‐2‐cycloalkenyl‐γ‐butyrolactones were synthesised from 2‐(cycloalken‐1′‐yl) carboxylic acids and epoxides using lithium naphthalenide in the presence of diethylamine. From 2‐(cyclohexen‐1′‐yl)propanoic acid and propylene oxide, 4‐hydroxy‐2‐(cyclohexen‐1′‐yl)‐2‐methylpentanoic acid was obtained. The latter easily cyclised to give 2‐(cyclohexen‐1′‐yl)‐2,4‐dimethyl‐γ‐butyrolactone. Similarly, 2,4‐dialkyl‐2‐(cycloalken‐1′‐yl)‐μ‐butyrolactones were prepared from other 3,4‐unsaturated carboxylic acids and epoxides. These lactones may be used as perfumery materials.
Influence of hydrogen bonding acceptor basicities of esters and ketones on the extraction of acetic and butyric acids from aqueous solutions
Authors: Hegazi Mohamed F. 
Published: July 2010

AbstractExtractions of acetic and butyric acids from aqueous solutions by various concentrations of carbonyl‐containing compounds dissolved in toluene were carried out at 30°C. The studied compounds included acetone, acetophenone, 2‐butanone, cyclohexanone, methyl, ethyl and iso‐amyl acetates, and mesityl oxide. The observed distribution ratios allowed the evaluation of association constants for the formation of carboxylic acid‐carbonyl‐containing compound complexes. These association constants correlate with the hydrogen bonding acceptor basicities of the esters and ketone used. The implementation of these results are discussed.
The catalytic decomposition of 4‐phenyl‐1,3‐dioxan on copper‐based catalysts
Authors: Červený Libor , Wurzlová Anna , Marhoul AntoníN , Růzika Vlastimil 
Published: July 2010

AbstractTransformations of 4‐phenyl‐1,3‐dioxan on copper‐based catalysts were investigated in an integral flow reactor in the gas phase in the temperature range 220–280°C. The main products of splitting were 3‐phenylpropanal, 3‐phenylpropan‐1‐ol and allylbenzene, and in some cases, styrene. Suitable reaction conditions were sought for the preparation of 3‐phenylpropanal and allylbenzene from 4‐phenyl‐1,3‐dioxan.
The influence of iron in synthetic zeolites on the decomposition of perborate
Authors: Burriesci Nicola , Giordano Nicola , Petrera Michele , Bart J. C. J. 
Published: July 2010

AbstractCommercial Grace 4A Zeolite exchanged with Fe3+ ions, pumice from different geological flows and their hydrothermally derived zeolites have been characterised as to the distribution and structural configuration of the iron content. Decomposition capacity of perborate (active constituent of detergent formulations) is not only determined by the total Fe content of the zeolite but also by the oxidation state, electron configuration and coordination. For a similar oxygen coordination, structural Fe2+ is more active in the decomposition of perborate than Fe3+. Exchanged Fe3+ ions of zeolites exhibit higher perborate decomposition capacity than structural Fe3+ or the Fe3+ of iron oxide.
Application of polarisation curves to the study of the electrochemical process for producing cuprous oxide
Authors: Vetere Vicente F. , Romagnoli Roberto 
Published: July 2010

AbstractPolarisation curves are useful for establishing the optimum experimental conditions for producing electrolytic cuprous oxide. They provide a reasonable means of determining the influence of each variable on cuprous oxide formation at an electrode surface. In this work, a sodium chloride solution was electrolysed, and sodium hydroxide and sodium nitrate (in several concentrations) were added in successive stages to determine the behaviour of the resultant systems. Finally, the effect of the presence of cuprous oxide on the cathodic behaviour of the electrode was studied. The working electrode was of copper and the experiments were conducted at different temperatures. The polarisation curves were obtained without agitating the liquid and with aerated and deaerated solutions. The passage of nitrogen during 30 min removed oxygen from the electrolyte.
Ammonium nitrate formation in low concentration mixtures of oxides of nitrogen and ammonia
Authors: Mearns Alexander M. , Ofosu‐Asiedu Kingsley 
Published: July 2010

AbstractThe formation of ammonium nitrate in a reaction system containing oxides of nitrogen, ammonia, water vapour and oxygen present in ppm quantities in nitrogen was investigated. The measured amounts of nitrate produced were compared with those predicted by use of a kinetic model for the reacting system. For any temperature there was an initial pressure of ammonia below which nitrate was not found. This pressure was determined solely by thermodynamic considerations. At higher pressures of nitrogen dioxide, equilibrium was quickly attained, but at low pressures nitrate was not always formed in the time of contact of reactants. Water vapour enhanced the rate of formation of nitrate. The work has relevance to the possibility of formation of ammonium nitrate in nitric acid plants and to its formation in the atmosphere.
Solvolysis of 5‐bromovanillin to syringaldehyde in the presence of copper as catalyst
Authors: Borgaonkar Hemant V. , Chandalia Sampatraj B. 
Published: July 2010

AbstractSolvolysis of substituted aromatic bromo‐aldehydes such as 5‐bromovanillin and 3,5‐dibromo‐4‐hydroxybenzaldehyde using anhydrous methanolic sodium methoxide was undertaken to produce syringaldehyde, which upon methylation with dimethyl sulphate gives 3,4,5‐trimethoxybenzaldehyde. The latter is an intermediate in the synthesis of trimethoprim, a well known antibacterial drug. The solvolysis was carried out in an agitated autoclave at 120°C, using dimethylformamide as a co‐solvent and metallic copper powder as catalyst. The effects of various parameters such as temperature, period of reaction, speed of agitation, type and loading of catalyst, addition of small amounts of water and concentration of co‐solvent on the conversion to syringaldehyde were examined.
Role of chromia in copper catalysts for dehydrogenation of ethanol
Authors: Prasad Y. S. , Padaliax B. D. , Raman S. K. 
Published: July 2010

AbstractDuring direct vapour phase dehydrogenation of ethanol, a copper‐on‐silica catalyst lost much of its activity in 100 h. Analysis with X‐ray diffraction, scanning electron microscopy and X‐ray photoemission showed that both sintering and carbon deposition accompanied the drop in activity. In catalysts in which chromia was also present copper was found to be in a more highly dispersed form which was more resistant to sintering. The chromia catalyst accumulated carbon comparably to those containing copper only.
A potentiometric titration and electrophoresis study of the iso‐electric points and the points of zero charge of alumina coatings on rutile
Authors: Cornell Rochelle M. , Posner Alan M. , Quirk James P. 
Published: July 2010

AbstractThe iso‐electric points (i.e.p.) and the points of zero charge (p.z.c.) of alumina coated rutile pigments have been determined using potentiometric titrations and electrophoresis techniques. The alumina coated rutiles all had a p.z.c. close to pH9. The i.e.p. of coatings precipitated in an alkaline medium were close to pH7, while those of coatings precipitated in acid media were around pH5. The discrepancy between the values of the i.e.p. and the p.z.c. is thought to have arisen because the electrophoresis technique measures only the charge on the outer alumina coating, while the i.e.p. (found by titration) is a combination of charge properties of both the alumina and the underlying rutile (i.e.p. 3.7). It is suggested that the pigments whose coatings were precipitated in an alkaline medium have the higher i.e.p. because the alumina shields the rutile more effectively than does alumina that was precipitated in acid media.
Competitive hydrogenation of olefinic substrates on a Pt/SiO2 catalyst
Authors: Červený Libor , Mojžíšová Jana , Rr̊žička Vlastimil 
Published: July 2010

AbstractThe effect of structure of substrates and solvents on the process of competitive hydrogenation of binary mixtures of olefinic substrates in the liquid state on 5% Pt/SiO2 catalyst has been investigated. The hydrogenations were carried out at 20°C under atmospheric pressure of hydrogen in the absence of solvent, in methanol and in cyclohexane; one series was also performed in sec‐butanol and in tert‐butanol. Selectivity changed markedly owing to the different adsorptivity of the substrates. In more polar solvents hydrogenation of less polar substates was relatively preferred.
The clay mineral content of various rock types compared with the methylene blue value
Authors: Hills J. F. , Pettifer G. S. 
Published: July 2010

AbstractThe methylene blue test has been developed in France for giving an overall assessment of the clay characteristics of an aggregate. The Department of the Environment, Northern Ireland, introduced the test into a specification to indicate the soundness of basalt and gritstone aggregates—the test being carried out on finely ground samples. As the test was unfamiliar in the UK, it has been investigated. A detailed and expanded test‐method has been written and 28 samples, mainly from basic igneous rock sources, have been tested. Experiments have shown that the particle size of the test‐specimen affects the result (the ‘blue value’). The clay contents of the samples, and the swelling properties of the clay minerals, have been determined by X‐ray diffraction of the air‐dry and glycolated samples. Where the samples were of a suitable size, the water absorption has been measured. The correlations between the blue value and the following parameters are discussed: the clay content; the swelling properties; and the water absorption. It is concluded that the methylene blue test, carried out on a powdered sample, should not be used by itself to judge whether a source of aggregate should be accepted or rejected.
The methylene blue dye adsorption test in relation to aggregate drying shrinkage
Authors: Hosking J. R. , Pike D. C. 
Published: July 2010

AbstractThe Digest 35 method is commonly used in specifications to identify aggregates that are likely to produce concrete with high drying‐shrinkage characteristics. However this test is protracted and monopolises equipment for long periods of time. Studies of two variants of a methylene blue dye adsorption test are described. The main findings were: (1) The methylene blue dye adsorption test is simple, inexpensive and rapid. Such a test could provide a screening procedure that would reduce the number of Digest 35 tests needed. (2) With the exception of limestone aggregates, good correlation was found between the results of the dye and the Digest 35 tests. (3) The variant using small single‐sized samples gave the higher adsorption values and yielded a better separation. Using large real‐sized samples gave lower and less well‐separated results; however sampling error would be less and there would be some saving in time. (4) Care would be needed in the specification of a standard dye test because results were found to be sensitive to changes in test conditions.