bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of saturated hydrocarbons II. oxidation of cycloparaffins by chromic acid
Authors: Moussa G. E. M. , Omar M. T.
Published: July 2010

The 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

The 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

The 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

A 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

The 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

The 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

An 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

The 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

Dehydration 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

The 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.
Measurement of friction and contact resistance of a single carbon fibre running against a copper ring
Authors: Wiggs P. K. C.
Published: July 2010

The friction and constant drop of a single fibre, acting as a brush, was measured, the fibre acting as its own dynamometer. Under such conditions, no co‐operative effects between adjacent fibres could occur.
Stability of a porous catalyst subjected to carbon deposition
Authors: Firth J. G. , Holland H. B.
Published: July 2010

A 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

The 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

The 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

Pentachlorophenol 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

The 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

The 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

The 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.
Effects of some esters on friction with particular reference to railway locomotion
Authors: Dyson R. W. , Loomba G. S.
Published: July 2010

Adhesion has become an increasing problem on railways. Work is described in which the effects of certain esters on the coefficient of friction were measured with apparatus designed to simulate wheel‐rail conditions. The results are reported and discussed.
Vapour‐liquid equilibrium data for the n‐pentane‐benzene system
Authors: Wang Jack L. H. , Lu Benjamin C.‐Y.
Published: July 2010

Isothermal 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.
The glass‐ionomer cement, a new translucent dental filling material
Authors: Wilson A. D. , Kent B. E.
Published: July 2010

A new translucent cement, the product of the reaction between ion‐leachable glass and an aqueous solution of polyacrylic acid, is described. Its properties, with particular reference to dental applications, are reported and a proposed setting mechanism is advanced.
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

Goethite, 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 evaporation of heat sensitive foodstuff liquids
Authors: Clarke R. J.
Published: July 2010

An introduction to a symposium on ‘The evaporation of heat sensitive foodstuff liquids’ is given and a brief historical resume of the subject is presented together with comments on the processes involved.
The photochemistry of triphenylmethane dyes in films of poly(methylmethacrylate)
Authors: Owen E. D. , Allen R. T.
Published: July 2010

Photobleaching 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

The 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

Egyptian 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

Water 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

Production 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

Steady 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

The 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.
Studies on the pulping of egyptian cotton linters by the nitric acid process
Authors: Abou‐State M. Amine , El‐Megeid Fouad F. Abd
Published: July 2010

Egyptian cotton linters were pulped by the nitric acid process. In order to reduce the high ash and silica contents of the resulting pulps it was found necessary to apply hot refining with sodium hydroxide solution. Different conditions of concentration, temperature, and pressure in the refining step were investigated. Refining before and during bleaching were compared.
Study of solvents for butadiene extraction by gas chromatography
Authors: Rawat B. S. , Mallik K. L. , Gulati I. B.
Published: July 2010

Six solvents have been studied by GLC for separation of 1,3‐butadiene from C4‐olefins having close boiling points. Infinite dilution activity coefficients and partition coefficients of five olefins have been determined in these solvents by conventional GLC‐technique at 30 °C. Relative volatilities of olefins in solvents have been calculated and on this basis the solvents have been compared.
The use of PVC powder as a subtractive agent in gas chromatography
Authors: Jamieson I. L.
Published: July 2010

An investigation is described in which subtraction “loops” filled with PVC powder have been used to study the affinity between the powder and model compounds. Optimum temperature conditions are 70 °C. The study reveals that the PVC has a strong affinity for aromatic compounds and compounds containing functional groups although this is qualified by the configuration of the molecule. It is shown that in view of these properties PVC can be used in subtraction “loops” as an aid to the identification of aromatics in mixtures of aromatics, n‐, iso‐ and cycloparaffins and also that its effectiveness in differentiating between aromatics and n‐paraffins is comparable with molecular sieve 5A. Its behaviour is different, however, in that it removes aromatics whereas the molecular sieve 5A removes the n‐paraffins. It is as effective as molecular sieve 5A in removing hydrocarbons containing functional groups. The PVC is cheap, requires no preparation prior to use and when “exhausted” it can be readily replaced.
Ternary vapour‐liquid equilibria of the system acetone+chloroform+tetrachloroethylene
Authors: Dakshinamurty P. , Rao P. Venkateswara , Chiranjivi C.
Published: July 2010

Isobaric vapour‐liquid equilibrium data of the ternary system acetone + chloroform + tetrachloroethylene were determined at 760 mmHg total pressure using a modified Colburn still. The activity coefficient data were satisfactorily tested for their thermodynamic consistency by the method of McDermott and Ellis and a satisfactory correlation was also obtained through Wohl's three suffix Margules ternary equations without a ternary constant. No ternary azeotrope was observed.
Effect of dialdehydes on the viscosity and optical rotation of gelatin
Authors: Courts A. , Homan P.
Published: July 2010

Monoaldehydes, other than formaldehyde, do not increase the viscosity of gelatin. Dialdehydes can increase viscosities, the order of efficiency being.

Glutaraldehyde increases the specific rotation of gelatin sols and gels but this effect usually requires a maturing time before it becomes apparent. After 18 h the increase is about 8%. Hence molecular order can adjust within gel structure. Cross‐linking gelatin does not improve the mechanical hardness of the film produced, as shown by indentation measurements.

The specific rotation of gelatin film is about one‐third the value of gelatin in the sol state.
Significance of the solubility of hydrocarbon gases in liquids in relation to the intermolecular structure of liquids and the essential pattern of data for all gases
Authors: Gerrard William
Published: July 2010

Solubility data expressed as mole ratio, xRH (moles of RH per mole of liquid S) have been measured for propane and n‐butane in a number of type‐representative organic liquids, S, at different temperatures, t °C, and pressures, pRH ≤ 760 mm. These data, and those for methane, ethane and radon, afford support in the development of the essential pattern of data for all gases, A, and all liquids, S. This pattern indicates that the first factor determining the solubility of any gas, A, in any liquid, S, is its tendency to condense to a liquid at the operational temperature, t °C (e.g. 0 °C to 25 °C), shown by its vapour pressure p°A over liquid A (or its equivalent for a gas above the critical temperature) at t °C. Since p°A emerges from the b.p. of A at 1 atm, and b.p. data are readily seen in text‐books, the b.p. may be taken as an initial index of the first factor. In the NA–pA diagram for a given gas A and different liquids, S, at a fixed t °C, NA being the mole fraction of A, the straight line joining p°A with pA = 0 is herein called the reference line, the R‐line, of A; it is a real property of A, and it represents the plot of NA–pA for a hypothetical liquid, S, having in effect an overall inter‐molecular structure equivalent to liquid A, in imagination, A itself. The NA–pA plot for another liquid, S, involves a second and a third factor, the second being the intermolecular structure of S, in a dynamic sense, and the third, the inevitable interaction of A with S. These factors are deemed to emerge from changes in electron density, designated for the present as acid‐base functions. The spread of xRH values is indicated by xPrH = 0.322, xBuH = 5.25, for di‐n‐octyl ether; xPrH = about 0.000042, xBuH = about 0.000040, for water, for 5 °C and PRH = 760 mmHg.
A multilayer thickness relationship applicable to pore size analysis of silica gel
Authors: Girgis Badie S.
Published: July 2010

A single multilayer curve was arrived at for the adsorption of nitrogen on silica gel. An empirical equation, fitted to the curve, proved to be suitable in the pore size analysis of 26 samples of silica gels; specific surface areas from 178 to 814 m2/g, mean pore radii of 12.6 up to 74.4 Å, and total pore volumes of 0.5126 to 0.8613 ml/g. Cumulative surface areas were evaluated by the procedures of BJH, Cranston and Inkley, and Roberts; the values obtained were generally in agreement with specific surface areas obtained by the BET equation, SBET, within ± 5%. The empirical equation is completely independent of the structural characteristics of the material. Comparison was made with data obtained by the use of the method of Mingle and Smith, for evaluating multilayer thickness, and which depends on both mean pore radius, and BET‐C value, for each single solid. Good concordance appears between the cumulative surface areas, as well as the pore size distributions, calculated by employing either this latter t‐estimate or the empirical equation.
Separation of uin‐ and multivalent cations and selective de‐ionisation by a phosphonic cation exchanger
Authors: Kadlec Václav , Matějka Zdeněk
Published: July 2010

The phosphonic cation exchanger in its free acid form is able to remove multivalent cations even from neutral and medium acidic solutions of salts of strong acids completely, and is regenerated by a stoichiometric amount of a regenerating agent. It is therefore possible to separate multivalent cations from univalent cations in a simple way by means of a phosphonic cation exchanger, followed by a weakly basic anion exchange resin. This results in a selective or partial de‐ionisation of solutions with an eventual recovery of multivalent cations using an economical regeneration dosage and with a minimum of waste.
An empirical thermodynamic model for the ammonia—water—carbon dioxide system at urea synthesis conditions
Authors: Lemkowitz Saul M. , De Cooker Mario G. R. T. , Van Den Berg Pieter J.
Published: July 2010

An empirical thermodynamic model for the NH3–H2OCO2 system at equilibrium at urea synthesis conditions (140 ≤ T ≤ 200 °C, 50 ≤ P ≤ 250 atm, 2.4 ≤ NH3/CO2 ≤ 6, H2O/CO2 ≤ 0.5) is presented. This model can quantitatively or semi‐quantitatively describe a number of important phenomena in the urea synthesis, such as the bubble‐point and gas—liquid equilibrium conditions and the effect of excess ammonia and water on the conversion to urea in the liquid phase. The model also sheds light on the problem of the conversion to urea at high temperatures (T > 190–200 °C).
Carnallite decomposition into magnesia, hydrochloric acid and potassium chloride: A thermal analysis study; formation of pure periclase
Authors: Ashboren David
Published: July 2010

A thermal analysis study of the one‐stage decomposition of small (mg) quantities of carnallite, KCl. MgCl2, 6H2O → KCl + MgO + 5H2O ↑ + 2HCl ↓, showed that dehydration and hydrolysis require temperatures above 300 °C. Decomposition of greater amounts, and analysis of the products, showed that at 450 °C, 88 to 90% of the magnesium occurs as chloride‐free high‐purity periclase. At higher temperatures increasing amounts of chlorides remain in the periclase and are difficult to separate. Unglazed porcelain is a suitable material for the decomposition vessel.
A study of the reaction of dry hydrogen chloride with white lead suspended in di—2—ethyl hexyl phthalate at 182 °C
Authors: John Michell E. W.
Published: July 2010

In order to test certain ideas which have recently been formulated on the way in which basic lead compounds stabilise polyvinyl chloride against thermal decomposition, the reaction of dry hydrogen chloride with a suspension of white lead in hot di‐2‐ethyl hexyl phthalate was studied by withdrawing samples and examining the solids by X‐ray diffraction. Normal lead phthalate, and an uncharacterised substance which has been called “basic lead chloride X”, were formed initially. Subsequently, this basic lead chloride X was converted to normal lead chloride.

The continuous formation of normal lead phthalate in this experiment contrasts with observations made on the crystalline products of stabilising reactions in PVC blends containing basic lead carbonates, and suggests that there are fundamental differences between the reaction mechanisms which prevail in these two systems. It is proposed that the results obtained with PVC blends are best explained in terms of free‐radical mechanisms for thermal decomposition and stabilisation of this polymer, whereas the results obtained in the present experiment can be explained by a simple acid—base type reaction.

X‐ray powder diffraction data are tabulated for normal lead phthalate.
Dimethyl sulphoxide as a solvent for amylose in the determination of amylolytic activity
Authors: Griffin Patrick J. , Fogarty William M.
Published: July 2010

Amylose readily dissolves in dimethyl sulphoxide (DMSO) to give clear colourless solution which is stable and forms a convenient stock amylose solution for amylase determinations. Dimethyl sulphoxide has no inhibitory effect on different amylolytic enzymes at the concentrations required for enzyme assay.
Production of cyclodextrin glycosyltransferase by batch and chemostat culture of Bacillus macerans in chemically defined medium
Authors: Lane A. G. , Pirt S. J.
Published: July 2010

A chemically defined medium for cultivation of Bacillus macerans is reported. Growth rates and cyclodextrin glycosyltransferase (CGT) titres obtained were similar to those obtained using media containing potato extract. The proteins in supernatant fluids from a batch culture were separated by disc electrophoresis and results obtained showed that CGT was produced after growth ceased, in agreement with results of activity measurements. The maximum growth rate in the chemostat considerably exceeded that in batch culture; this anomalous effect is unexplained. High CGT titres were produced at low dilution rates (0.03 to 0.05 h−1) but residual starch was present at higher dilution rates and CGT synthesis was repressed. Enzyme titres obtained in chemostat cultures at D = 0.03 h−1 using defined medium containing 13 g starch/1 were 2.75 times greater than the maximum obtainable by batch cultivation and about 20 times greater than those reported by other workers using medium containing diced potato and CaCO3. A two‐stage chemostat cultivation was performed using dilution rates of 0.1 h−1 and 0.033 h−1 in the first and second stages, respectively. The CGT activity in the second stage increased by 57 per cent when a maintenance feed of starch was supplied at 0.08 g g−1 dry biomass h−1. Only negligible CGT titres were obtained when a dilution rate of 0.5 h−1 was used in the first stage. For reasons not understood, DM medium would not support biomass yields greater than 5 g 1−1. This limitation was not due to production of an inhibitor, or to deficiency of N, Fe, Zn, Mn, thiamine or biotin.
Loss of copper from oxychlorination catalysts
Authors: Aharoni Chaim , Inbar Jonathan
Published: July 2010

During the oxychlorination process, there are losses of copper from the catalyst as a result of a reaction with the walls of the reactor: the cupric ions are reduced to metallic copper and deposited on the walls. We have observed rates of deposition of the order of 10−2 g of copper per cm2 of walls per year, for walls of pure iron. The deposited copper was detected and estimated by electron‐probe microscopy. Attrition does not appreciably change the concentration of copper in the catalyst particles.
A quantitative theory of the action of microbes attached to a packed column: Relevant to trickling filter effluent purification and to microbial action in soil
Authors: Pirt S John
Published: July 2010

A packed column with microorganisms attached is regarded as a series of “theoretical compartments” each separated by a “theoretical film” of biomass. Liquid medium is supposed to pass down the column so that it remains for an equal time in each compartment. The theoretical film of biomass is assumed to have an active layer in contact with the liquid medium, the thickness of the active layer of biomass is estimated from the kinetics of diffusion of the limiting substrate. The efficiency of the column is represented by the number of theoretical compartments per unit length of column. In aerobic processes it is supposed that oxygen will be the rate‐limiting nutrient. Expressions are derived for the amounts of substrate that will be consumed in aerated and non‐aerated columns. The theory is applied to calculate some of the parameters of a trickling filter for effluent purification. The theory may be readily tested since it involves only measurable and meaningful parameters of a microbial culture.
The effect of temperature, light and some transitional metal ions on the sorption of sulphur dioxide by paper
Authors: Atherton James B. , Hudson F. Lyth , Hockey John A.
Published: July 2010

The sorption of sulphur dioxide by a series of laboratory‐made paper handsheets of typical furnishes was investigated. The gas phase SO2 concentrations used approached those found in city atmospheres. It was found that at fixed gas phase SO2 concentration, increase in temperature decreased the “pick‐up” rate. Copper and manganese ions were found to catalyse the fixation of sulphur dioxide but iron ions were found to be much less effective in this respect. Experiments conducted to assess the effect of light indicated that the rate of “pick‐up” was increased when the samples were exposed to sunlight; an effect most marked in the samples containing groundwood.
The use of a membrane electrode to study the crystallisation of calcium sulphate from aqueous solution: I. The relation between calcium ion activity and crystallisation rate
Authors: Ching William , McCartney Eric R.
Published: July 2010

A semipermeable membrane of sulphonated polyvinylidene fluoride was used as the basis of a membrane electrode for the measurement of the activity of calcium ions in solution. By following the change in calcium ion activity as calcium sulphate dihydrate crystallised from aqueous solution, an equation for the rate of crystallisation was derived.
Liquid phase oxidation of propionaldehyde: Kinetics of initiation step
Authors: Govindarao V. M. H. , Gurumurthy C. V.
Published: July 2010

A method of determining the rate of the initiation reaction in the liquid phase oxidation of propionaldehyde is described.
Anodic behaviour and passivation of tin in alkaline—stannate plating solutions
Authors: Azzam A. M. , Abd Rehim S. S. El , Fawzy M. H.
Published: July 2010

The electrochemical behaviour of tin was studied in sodium hydroxide solutions as well as in alkaline—stannate plating solutions using potential—time and current—time measurements. Cyclic cathodic and anodic polarisation, as well as anodic decay curves were traced. Results indicate that the galvanostatic potential—time curves consisted of three main parts: an initial linear instantaneous rise of potential caused by the charging of the double layer, an intermediate rise caused by stannous and stannic hydroxides and oxides formation at their respective thermodynamic potentials, and a final steady potential associated with oxygen evolution.

Current‐time measurements show that tin could be passivated in all solutions used and at different current densities. In all cases oxygen evolution was noticed at the end of passivation. Free surface area of tin electrode in various solutions used was calculated using the Müller formula. The porosity of the surface film was found to depend on the composition of the solution.
Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene
Authors: Oltay Ernst , Penninger Johannes M. L. , Konter Willem A. N.
Published: July 2010

The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2‐methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low concentrations of diphenylmethane were detected at the highest temperature. This indicates that the opening of the phenylCH2 bond in fluorene is much faster than the splitting of the phenyl—phenyl bond. The splitting of the phenyl—phenyl bond in biphenyl, however, proceeded with a rate equal to the splitting of the phenylCH2 bond in fluorene and the phenylCH3 bond in 2‐methylbiphenyl.
Ageing of some high surface area solids
Authors: Bye Gerald C. , Chigbo Gilbert O.
Published: July 2010

The ageing (fall in surface area) of samples of aluminium hydroxide has been studied by observing the changes in surface area and porous texture revealed by nitrogen adsorption. Ageing was carried out over phosphorus pentoxide and at 33% r.h. The effect of this change in r.h. depended on the texture of the aluminium hydroxide. Ageing was faster at 33% r.h. in the amorphous form which contained discrete flocs. Pseudoboehmite behaved as a true xerogel and some samples even increased in surface area by swelling when stored at the higher humidity.

Some data for calcium silicate hydrates and samples of a commercial pyrogenic silica are included for comparison. The former were prepared in powder and paste (xerogel) form. The two forms responded differently to the two humidities but in the opposite sense to the corresponding aluminium hydroxide textures: thus the surface area of pastes fell more rapidly at the higher r.h. The surface area of samples of the silica fell when they were stored normally in air tight containers. They eventually reached steady values and a reduction of a similar magnitude could be produced rapidly by agglomerating the spherical particles in hot water.

Mechanisms of ageing involving simple adhesion and its reverse depending on r.h., hydroxyl group condensation, and sintering aided by dissolution or surface diffusion are discussed.
Salts in gypsum and calcined gypsum
Authors: King George A. , Ridge Mayhew J. , Walker Graham S.
Published: July 2010

Chloride in a number of samples of gypsum and calcined gypsum has been determined by Surkevicius's method and by nephelometry. Results from the former method are confirmed. Sodium was determined by atomic absorption spectroscopy and the content found to be considerably greater than the equivalent of the chloride. Two of the samples appeared to contain close to 0.1% of Na2SO4 and it is suggested that standards for the quality of gypsum should specify the determination of sodium as well as that of chloride.
Hydration of tricalcium silicate at elevated temperatures
Authors: Odler Ivan , Skalny Jan
Published: July 2010

The early hydration of tricalcium silicate, Ca3SiO5, has been studied at temperatures of 25, 50, 75 and 100 °C. Changes in the chemical composition of hydration products formed at different temperatures were followed by means of chemical, thermal and X‐ray analyses, and correlated with surface area and pore structure measurements reported previously.
Oxidation of ferrous sulphate in presence of sodium carbonate
Authors: Prasad T. P. , Suryanarayana A.
Published: July 2010

Isothermal oxidation of ferrous sulphate heptahydrate in presence and absence of sodium carbonate has been carried out in the temperature range 205 to 265 °C. The oxidation proceeds in two steps. The rate constants for the oxidation at various temperatures have been calculated. The results indicate that the low temperature mechanism of oxidation proposed earlier does not hold good at higher temperatures.
Determination of oxygen‐to‐metal ratios in metal oxide nuclear fuels
Authors: Gurumurthy Coimbatore V.
Published: July 2010

Methods for the determination of O/M ratios in uranium and uranium‐plutonium oxide nuclear fuels are reported based on an extensive literature survey. The salient features, as well as the merits and drawbacks of each method are critically reviewed. The need for a fast direct method, by which the simpler indirect methods may be checked, is met by the carbon‐reduction method.
Kinetics of the decomposition of perpropionic acid
Authors: Gurumurthy Coimbatore V.
Published: July 2010

The decomposition of perpropionic acid, in the presence of manganese propionate catalyst is studied by the capacity‐flow method. The reaction is found to be second order with respect to peracid concentration and first order with respect to catalyst concentration. The activation energy is 10.2 kcal/mol. The mechanism of the reaction is discussed along with the possible modes of by‐product formation.
Formation of a glass‐ionomer cement based on an lon‐leachable glass and polyacrylic acid
Authors: Crisp Stephen , Wilson Alan D.
Published: July 2010

The chemistry of the cement‐forming reaction between a fluorine‐containing calcium aluminosilicate glass and aqueous solutions of poly(acrylic acid) has been studied using infrared spectroscopy and classical chemical procedures. It was concluded that calcium, aluminium and fluoride ions were leached from the glass leaving a relict of silica gel. These ions migrated into the polyelectrolyte phase where the cations cross‐linked polyanionic chains causing the system to gel. Initial set, which takes place within 10 minutes, was attributed to the formation of the calcium salt, the aluminium salt forming later and contributing to the hardening of the cement. Reactions continued for at least 48 h. The role of ion‐binding in the reaction is discussed.
Extraction of titanium dioxide (TiO2) from ilmenite and titaniferous slag
Authors: Easteal Allan J. , Udy David J.
Published: July 2010

Solutions of ilmenite (FeTiO3) and a titaniferous slag, in fused Li2O. 2B2O3 and Li2O. 4B2O3, yield on cooling compounds tentatively identified as LiFe2.5Ti3O9 and Li2Fe3Ti2.5O9 respectively. Both compounds are orthorhombic, and have the pseudobrookite structure.

The ilmenite solutions yield, in addition, rutile (TiO2). The yield of rutile increases from about 1 to 24% (w/w) of the products, when the solvent is changed from Li2O. 2B2O3 to Li2O. 4B2O3. Substitution of K2O. 4B2O3 for the latter solvent decreases the yield of rutile to c. 10%. The yield of rutile is approximately in inverse proportion to the Lux—Flood basicity of the borate solvent.
Some observations on calcium silicate brick specimens in the autoclave
Authors: Walker Richard C. , Purton Michael John
Published: July 2010

An autoclave with an externally generated steam supply and fitted with windows has been used to observe calcium silicate brick specimens with varying initial moisture contents during the autoclaving cycle. In particular, gains and losses in weight due to condensation and evaporation of water were recorded.

Tests on the autoclaved specimens indicated that bulk density, compressive and transverse strength varied with initial water contents of the mix within the range 4 to 14%. Specimens with high water contents expanded and cracked during autoclaving. C2SH(A) rather than CSH(II) was formed in mixes with low water contents at short autoclaving times.