bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory studies on solvent extraction of low‐temperature tar oils by aqueous sodium salicylate
Authors: Raj P. , Khaleel Akmal M. A. , Subba Rao Y. V. , Moinuddin Ahmed S. , Vaidyeswaran R. 
Published: July 2010

AbstractThe use of aqueous saturated sodium salicylate for the extraction of tar acids from a low‐temperature tar fraction is discussed. Solubility and equilibrium data for the system:neutral oil‐tar acids‐aqueous sodium salicylate when plotted on a ternary diagram showed two types of curves: an ordinary bite type and another a loop containing solid and liquid phases. The tie‐line data agree with most of the empirical relationships reported in the literature. The plait point for the system had a tar acid concentration of 47%. The results have been compared with the earlier data for the system: phenol‐α‐methylnaphthalene‐aqueous sodium salicylate.
Performance of a rotating disc contactor using the system carbon tetrachloride–acetic acid–water
Authors: Thomas W. J. 
Published: July 2010

AbstractA typical rotating disc contactor of small scale was examined using the system carbon tetrachloride–acetic acid–water. The efficiency of extraction was established experimentally for a range of operating variables including rotational speed and phase flow rates and ratios. The results are compared with those of Russian authors for the same liquid system.
Reactions of saturated hydrocarbons I. Oxidation of isoparaffins by chromic acid
Authors: Moussa G. E. M. , Omar M. T. 
Published: July 2010

AbstractMeasurements of the rate of reduction of chromium(VI) oxide in acetic acid–acetic anhydride solution by 2‐methyl‐pentane, 3‐methylpentane, 2,3‐dimethylbutane and 2,4‐dimethylpentane show that the initial rate depends on the number and nature of carbon atoms in the hydrocarbon. When steric or other interaction effects prevail between adjacent atoms or groups in the molecule, these effects also influence the rate.The values obtained for the oxidation rates agree with those calculated from a proposed expression (Rnp+R'ns+R'nt)/(np+ns+nt) based on the formula of Chambers & Ubbelohde.
Reactions of saturated hydrocarbons II. oxidation of cycloparaffins by chromic acid
Authors: Moussa G. E. M. , Omar M. T. 
Published: July 2010

AbstractThe rate of reduction of chromium(VI) oxide in acetic acid–acetic anhydride solution by a number of cyclo‐paraffins has been measured. The values obtained agree with those calculated from the proposed expression (Rnp+R'ns+R''nt)/(np+ns+nt), based on the Chambers & Ubbelohde equation, with some deviations. Trans‐1,2‐dimethylcyclohexane oxidised at a rate slower than expected whilst cyclopentane and methylcyclopentane showed a rate higher than the calculated value. A tentative explanation is given based on confornational analysis and strain energy considerations.
Sampling of road surfacing materials
Authors: Goodsall G. D. , Mathews D. H. 
Published: July 2010

AbstractThe meaning and purpose of sampling are discussed. Results are presented from a series of road trials on the sampling of asphalt mixtures to demonstrate the importance of bias and variability introduced into test measurements by sampling. Further variability is introduced by the reduction in size by quartering of gross samples to the size required for testing; it is shown that this variability is reduced when a riffling technique is used. It is usual to adjust the measured binder and filler contents of asphalt for the disturbance caused by sampling. Evidence is presented to show that the adjustments in current use may not be well chosen and some more appropriate factors are suggested.
Nucleation and growth of ammonium sulphate crystals from aqueous solution
Authors: Mullin J. W. , Chakraborty M. , Mehta K. 
Published: July 2010

AbstractThe refractive index, density and viscosity of aqueous solutions of ammonium sulphate have been measured in the range 20‐30°. The solubility of ammonium sulphate was checked over the range 20‐45° by measuring saturation temperatures in a simple apparatus. The same technique was also used for nucleation studies; the maximum allowable undercoolings with and without seed crystals range from ˜ 3.5° and 5°, respectively, for fast cooling rates, to ˜ 1.5 and 3.5° for slow.Growth rates of two major faces (100) and (001) of ammonium sulphate crystals were measured in a flow cell. The (100) face growth rate is directly proportional to the concentration driving force and independent of solution velocity, whereas that of the (001) face appears to be a second‐order process and slightly velocity‐dependent.
Molecular vibration and the ‘green’ odour
Authors: Wright R. H. 
Published: July 2010

AbstractA comparison of odour with i.r. bands for 13 compounds showed an association between ‘green’ character and the position of the bands, especially the pattern A°CD, where A is 215–234, C 275–294 and D 300–319 cm−1 and B denotes the absence of the band B 250–269 cm−1. However, this correlation gives only a rough evaluation. Of 12 compounds selected on a spectroscopic basis as having the ABCD pattern, 6 were found to have the expected ‘green’ odour.
Fluoride activation in the flotation of chromite
Authors: Abido A. M. 
Published: July 2010

AbstractThe responses of chromite and the gangue minerals olivine and serpentine commonly associated with it to fluoride activation in soap and anine flotation were studied.Hydrofluoric acid was shown to have good selective properties in amine flotation of chromite that qualify it as a possible flotation reagent. It seems that hydrofluoric acid could be adsorbed strongly and preferentially on the chromite surface to give the extremely insoluble CrF2− ion that exhibits great affinity for the positively charged dodecylammonium ion, leading to the formation of water‐repellent coatings. On the other hand, hydrofluoric acid attacks the magnesium and ferrous sites on the surface of olivine and serpentine with the formation of soluble magnesium and ferrous fluorides. Hydrofluoric acid also attacks the silicon sites at pH < 4 with the formation of fluosilicic acid, and therefore impedes the formation of collector‐coating on the surface of olivine and serpentine.In contrast, sodium fluosilicate had a detrimental effect on both soap and amine flotation of chromite. This is probable due to its dissociation to SiF62− ions which are probably adsorbed on to cationic sites of chromite and gangue minerals with the formation of the corresponding negatively charged fluosilicates. As a consquence, dodecylammonium ions could be attached to the surface of chromite and gangue minerals, whereas oleate ions could not and hence the selectivity is completely destroyed.
Vaporisation of sulphamic acid
Authors: Halstead W. D. 
Published: July 2010

AbstractThe vaporisation of sulphamic acid, NH2SO3H, at temperatures between 600 K and 740 K has been studied. The chemical constitution of the acid changes on melting in a manner which may be described by the equation: 12NH2SO3H→6NH4HSO4 + (NHSO2)6.SO3/H2SO4 is released thereafter by the hydrolysis of the hexasulphimide (NHSO2)6. the requisite H2O being derived mainly from the decomposition of the NH4HSO4.SO3/H2SO4 release is virtually complete by the time the acid has lost 20% of its original weight. During further vaporisation, SO2 is the only vapour‐phase sulphur‐containing species to be released in significant quantities, the unevaporated residue comprising mainly of a 2:2:1 molar mixture of (NH4)2SO4, NH4HSO4 and NH2(SO2NH)2SO2NH2.The use of sulphamic acid as a conditioner for the fly ash found in the flue gases of coal‐fired boiler plant is discussed.
Chemistry of by‐product gypsum and plaster. I. Identity of an important solid solution impurity
Authors: Kitchen D. , Skinner (deceased) W. J. 
Published: July 2010

AbstractAn investigation has been made into why calcium sulphate β‐hemihydrate, derived from the by‐product gypsum of wet‐process phosphoric acid manufacture, can, when derived from certain types of phosphate rock, be insensitive to hydration retarders. Aluminium and fluorine, which are common impurities in phosphate rock, form complex aluminofluorides in the phosphoric acid reaction liquor; and gypsum crystallising from this system has its crystal habit and physical properties modified by these complexes. The hemihydrate calcined from the gypsum has a setting time that is less amenable to control by retarder addition than the setting time of pure hemihydrate. The gypsum crystals exhibiting this effect incorporate a solid solution impurity which has been identified as AlF52− substituting for SO42− ions in the crystal lattice.
Chemistry of by‐product gypsum and plaster. II. Chemistry of co‐crystalline ALF52− during gypsum calcination and subsequent mixing of the hemihydrate with water
Authors: Kitchen D. , Skinner (deceased) W. J. 
Published: July 2010

AbstractThe chemistry was studied of the complex alumino fluorides produced in the preparation and hydration of CaSO4.1/2H2O derived from by‐product gypsum. Co‐crystalline AlF52− remains unchanged during dry calcination of gypsum to β‐hemihydrate, but when the hemihydrate is mixed with water, dissolution of the host lattice releases the AlF52− ions into the aqueous phase, whereupon dissociation takes place. The products of this dissociation are dependent upon the amount of dissolved phosphate present. In the absence of phosphate the predominant fluoroaluminium ion formed is AlF2+ but in the presence of an equimolar, or larger, amount of orthophosphate, AlF(H2PO4)+ becomes predominant. Intermediate quantities of phosphate result in proportionate mixtures of products being formed.
Reactions of unsaturated compounds I. Structure and chromic acid oxidation of the hydrocarbon C17H18 obtained by the dehydration of 1,1‐diphenyl‐2,2‐dimethylpropan‐1‐ol
Authors: Moussa G. E. M. , Eweiss N. F. 
Published: July 2010

AbstractDehydration of the carbinol 1,1‐diphenyl‐2,2‐dimethylpropan‐1‐ol gives a hydrocarbon C17H18 which was identified as 2‐methyl‐3,3‐diphenylbut‐1‐ene.Oxidation of C17H18 with chromium trioxide in acetic anhydride gave acetone, acetophenone, benzophenone and α‐methyl‐β,β‐diphenylbutyric acid. Oxidation with chromium trioxide in aqueous sulphuric acid gave acetone, acetophenone, benzophenone and diphenylmethylacetic acid.A tentative explanation for the production of abnormal fission products and α‐methyl‐β,β‐diphenylbutyric acid is given.
Properties of hardened highly refractory basic cements as a function of in relation to their phase composition
Authors: El‐Rafei E. A. , Kamel M. R. 
Published: July 2010

AbstractThe phase, composition of the previously prepared three hardened highly refractory basic cements (dolomitic magnesite, periclase and dolomitic magnesite chrome) was established by the aid of d.t.a., t.g.a., microscopic examination, electron microscopy and X‐ray analysis.The following properties of these cements were determined: compressive strength, apparent porosity, linear shrinkage and ignition loss. These parameters were measured for each cement after 3 days air curing at ∼ 60% r.h. and after heating these cements to 110°, 450°, 600°, 800° and 1200°C.The variation in these parameters as a function of temperature was correlated in the light of their component phases.
Stability of a porous catalyst subjected to carbon deposition
Authors: Firth J. G. , Holland H. B. 
Published: July 2010

AbstractA study has been made of the stability of porous α‐aluminá‐based catalysts subjected to carbon deposition during the catalytic oxidation of methane. The most important factor in determining the stability, defined as the time taken before mechanical disintegration of the catalyst begins, was found to be the mechanical strength of the alumina. The stability was directly proportional to the mechanical strength.
Decomposition of simple alcohols, ethers and ketones in a microwave discharge
Authors: Liu S. W. , Wightman J. P. 
Published: July 2010

AbstractThe decomposition of various oxygen‐containing organic compounds including alcohols, ketones and ethers was studied in a microwave discharge at 0.3–2.0 torr in the absence of a diluent. Both gases and polymeric films were formed in each case and the extent of decomposition approached 100%. Hydrogen and carbon monoxide accounted for 90% of the total gaseous products. Trace amounts of gaseous low molecular‐weight hydrocarbons were also observed. The effect of pressure on the distribution of gaseous products was small. The gaseous products were similar to those predicted from reported high‐temperature equilibrium calculations.The C:O and the H:C ratios in the parent molecules were important parameters which determined the amount and the composition of the polymer film, respectively. The polymeric films formed in the discharge were characterised by several techniques including carbon‐hydrogen analysis, and i.r. and e.s.r. spectroscopy. The films were shown to have an average empirical formula of CH1.41O0.06 and to contain structural moieties of CO, CH3, CH2, CH and CC. The insoluble films were amorphous and contained free radicals. The polymeric films were thermally stable up to 200°c and decomposed at higher temperatures. The polymeric films formed were similar in all cases and independent of the nature of the parent molecule.It was inferred from the decomposition products that both the gases and the polymeric films were‐formed by the reaction of simple species such as CH and H in the microwave discharge.
Diffusivity of water in groundnut oil and paraffi oil
Authors: Hilder M. H. , van den Tempe M. 
Published: July 2010

AbstractThe difliisivity of water in parafin oil and grortndnrit oil has been measured at 24°c using a simple difusion cell.The measured diffusivity of water in parafin oil conipares well with previous determinations. The diffusivity of water in graundnut oil at 24°c and those predicted at higher temperatures are the only experimentally based data available at present.The measurment extend the data present range of knowledge to higher molecular weight and higher viscosity solvents aid reinforce the demanand of previous investigation for more experimental data outside the range of present correlations.
Fibre surface modification XI. The covalent attachment of fungicides to lignocellulosic fibres
Authors: Allan G. G. , Halabisky D. D. 
Published: July 2010

AbstractPentachlorophenol was covalently bonded to a softwood kraft pulp by an s‐triazine bridge formed from cyanuric chloride in a mild aqueous reaction system. The tensile properties of paper made from the polypentachlorophenoxy‐s‐triazinylated fibres containing 3.9% of combined fungicide were completely maintained for 49 days during fungal attack by Lenzites trabea. Protection is probably a result of the release of pentachlorophenol from the fibre triggered by the attacking fungus.
Electrochemical oxidation of propylene utilising a thallium redox system
Authors: Goodridge F. , King C. J. H. 
Published: July 2010

AbstractThe oxidation of propylene in the presence of electrochemically regenerated thallium(III) was investigated over a range of electrode potentials. Polarisation curves made with the aid of a rotating platinum disc electrode, as well as current efficiencies for the formation of propylene glycol and acetone, are presented. At electrode potentials <2.2 V(EH), product formation can be satisfactorily explained in terms of thallium(I) reoxidation. At higher electrode potentials, direct oxidation of the thallium‐propylene complex as well as further electrochemical oxidation of the products so obtained must be postulated.
Bubble‐point measurements in the ammonia‐carbon dioxide system
Authors: Lemkowitz S. M. , Goedegebuur J. , Berg P. J. 
Published: July 2010

AbstractThe bubble‐point pressures in the NH3‐CO2 system, at complete chemical equilibrium, have been measured in the range of 130–185°c corresponding to pressures of 30–175 atm. The NH3‐CO2 system exhibits a sharp pressure minimum; in the area of high NH3 concentration, critical behaviour and retrograde condensation have been found. The results, as part of the NH3‐H2O‐CO2 system, are discussed from the standpoint of chemical phase theory and are shown to be consistent with the NH3‐H2O and CO2‐H2O systems. The relation of these measurements to the commercial urea synthesis is also discussed.
Orthophosphates. XIII. Thermal decomposition of secondary calcium orthophosphate (CaHPO4) and secondary calcium orthophosphate dihydrate (CaHPO4.2H2O)
Authors: Duff E. J. 
Published: July 2010

AbstractThe thermal decomposition of CaHPO4 and CaHPO4.2H2 O was studied by thermogravimetric analysis, X‐ray powder diffraction, and infra‐red spectroscopy. At 105°c, two moles of CaHPO4.2H2O combine and eliminate 1 mole of H2O. The remaining three moles of hydration water are eliminated at 165°c. Decomposition of CaHPO4 occurs above this temperature, with formation of Ca2P2O7, at 270°c.
Vapour‐liquid equilibrium data for the n‐pentane‐benzene system
Authors: Wang Jack L. H. , Lu Benjamin C.‐Y. 
Published: July 2010

AbstractIsothermal vapour‐liquid equilibrium data were determined in a modified Dvorak and Boublik still for the binary system n‐pentane‐benzene at 35°, 40°, 45° and 50°c. Liquid activity coefficients, γ, were evaluated and correlated. Experimental equilibrium values were extrapolated to the isobaric condition of atmospheric pressure. The extrapolated data agree well with that reported by Myers.
An examination by nitrogen adsorption of the thermal decomposition of pure and silica‐doped goethite
Authors: Bye G. C. , Howard C. R. 
Published: July 2010

AbstractGoethite, pure and doped with silica by co‐precipitation, was calcined at temperatures up to 900°c. The textures of the goethites and derived iron oxides were examined by nitrogen adsorption and electron, microscopy. With the latter the progressive elimination at higher temperatures of the porosity created by dehydroxylation at 300°c was followed. A sample of iron oxide produced by calcination of pure goethite at 900°c was found to possess the simplest texture. The dimensionless adsorption isotherm for this sample, which is similar to that reported in the literature for alumina, provided the reference data used in the interpretation of the isotherms for the other samples. A number of features of the pore size data derived could be satisfactorily correlated with observations made in the electron microscope. Doping with silica caused the goethite needles to grow in spherulite‐like aggregates. This texture inhibited interparticle sintering at high temperatures but did not influence the behaviour of the pore system produced in the needles by dehydroxylation.
The photochemistry of triphenylmethane dyes in films of poly(methylmethacrylate)
Authors: Owen E. D. , Allen R. T. 
Published: July 2010

AbstractPhotobleaching of the halides of the triphenylmethane dyes crystal violet and malachite green in thin films of poly(methylmethacrylate) is described. The reaction proceeds via the triplet excited state of the dye which undergoes an intramolecular electron transfer reaction, forming the triarylmethyl and halogen free radicals. Quantum yields of triplet formation depend on the concentration of the dye which suggests that the intersystem crossing process involves more than one dye molecule. The rate of reaction depends on the rate at which radicals are formed which are free of the solvent cage and on the reactivity of the radicals.
Formation and surface properties of electron emissive coatings: X. Sintering of the alkaline‐earth formates
Authors: Judd M. D. , Pope M. I. , Wintrell C. G. 
Published: July 2010

AbstractThe thermal decomposition of calcium, strontium and barium formates has been studied by preparing a calcination series, under vacuum, up to 1100 °C. The results indicate that each major stage of the decomposition process gives rise to a corresponding increase in specific surface. One possible exception is the initial decomposition of barium formate. This substance melts, accompanied by violent evolution of gaseous products and exfoliation of the re‐solidified residue, thereby making it impossible to determine accurately the specific surface.
Effect of depithing on pulps from egyptian bagasse
Authors: Abou‐State M. Amine , El‐Morsy M. M. 
Published: July 2010

AbstractEgyptian bagasse was pulped by the prehydrolysis‐soda process followed by multi‐state bleaching. Raising the concentration of sodium hydroxide used in the second step of bleaching improved the chemical characteristics of the pulp. Depithing had to be applied to improve the degree of pulping and to reduce the ash content. The minimum ash content (0.07%) was arrived at either by carrying out depithing before prehydrolysis to the extent of 2%, or after prehydrolysis to the extent of 10%. Depithing before prehydrolysis was superior as it resulted in a better yield, higher alpha cellulose, and higher degree of whiteness.
Elastic constants calculated from adsorptive length change data on kaolinite rods
Authors: Metcalfe A. , Wilcock R. J. 
Published: July 2010

AbstractWater adsorption uptake and length‐change isotherms on extruded Kaolin samples have been determined both parallel and perpendicular to the extrusion axis. Elastic constants of the solid have been calculated using these data and the relationships due to Bangham and Maggs; these results compare favourably with those measured acoustically and reveal significant anisotropy of length change in extruded samples.
Fermentative production of mitomycins by Streptomyces caespitosus
Authors: Abou‐Zeid A. A. , Yousef A. A. 
Published: July 2010

AbstractProduction of mitomycin antibiotics by Streptomyces caespitosus was increased by the utilisation of molasses (1.0%) treated with 0.01 % potassium ferrocyanide and corn steep liquor (0.9 %). Three different fermentation media were used for the fermentation production of mitomycins. Appropriate amounts of ammonium sulphate, soluble starch, ferrous sulphate, magnesium sulphate, potassium dihydrogen phosphate, sodium chloride and calcium carbonate increased the antibiotic yield when added to the fermentation medium containing molasses and corn steep liquor. The addition of some individual amino acids, vitamins and organic acids to a base fermentation medium did not improve or increase its performance.
Molar growth yields and acid phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in carbon‐limited chemostat culture
Authors: Bolton P. G. , Rodgers P. J. , Dean A. C. R. 
Published: July 2010

AbstractSteady state molar growth yields were determined for Klebsiella aerogenes NCIB 418 growing aerobically in a minimal medium containing a wide range of substrates as sole carbon sources. The results are compared with those reported by others for batch culture conditions and the necessity for thorough adaptation to some carbon substrates, if maximum yields are to be obtained, is emphasised. The yields obtained when a second carbon substrate was presented to bacteria, already in the steady state of growth in glucose or acetate‐limited chemostats, are also reported. Glucose‐limited cultures readily metabolised various sugars but appreciable lags preceded their utilisation by acetate‐limited cultures. Acid phosphatase specific activities determined in organisms grown in these two substrate media not only confirmed and extended earlier ideas about the association between carbohydrate metabolism and the synthesis of the enzyme(s) but are also relevant if the production of the latter is envisaged. This is discussed.
Reversible isomerisation of alkyl aromatics
Authors: Badr M. Zarif A. 
Published: July 2010

AbstractThe isomerisation of different alkyl naphthalenes under the influence of anhydrous sulphonic acids, other Friedel‐Crafts and Lewis acid catalysts has been studied, where the alkyl groups undergo rearrangement during the isomerisation process. Isomerisation of benzylnaphthalenes, in presence of phenol and naphthols, resulted in the alkylation of such solvent nuclei, giving benzylphenols and benzylnaphthols together with the normal products of isomerisation.