bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetics of the vapour‐phase hydrogenation of benzene over a supported nickel catalyst in a stirred‐vessel reactor
Authors: Lakshmanan R. , Rouleau D.
Published: July 2010

The catalytic hydrogenation of benzene was investigated over a supported nickel catalyst in a continuous stirred‐vessel reactor between 260° and 450°F at atmospheric pressure. The effects of temperature, ratio of hydrogen to benzene and total feed rate (or contact time) on the conversion of benzene and yield of cyclohexane were determined.

The use of the stirred reactor helped to eliminate mass transfer limitations. The investigation was carried out using surface‐coated catalysts in order to eliminate pore diffusion which might otherwise mask the actual kinetics.

Studies of the mixing characteristics of the reactor were carried out under both reacting and non‐reacting conditions, by following conversion as a function of stirrer speed and by a tracer (pulse) technique, respectively.

The kinetic data were analysed to determine the most probable model to represent the reaction. The Houghen–Watson type analysis was carried out using non‐linear least squares instead of the usual linear one. The model that satisfactorily correlated the data over the entire temperature range describes the rate‐controlling step as the surface reaction between adsorbed hydrogen and adsorbed benzene, the hydrogen addition being simultaneous. The following Hougen–Watson type equation was proposed:r= keKH3KBPH3PB/(1+KHPH+KBPB+KCPC)4.

The constants in this rate equation were expressed as a function of temperature.
Solvent extraction using dialysis through artificial phase boundaries
Authors: Massoumi A. , Edrissi M. , Hedrick C. E.
Published: July 2010

Several solvent extraction systems were studied using a cellulose dialysis membrane as an artificial phase boundary separating one solvent phase from the other. Solutes were allowed to come to extraction equilibrium by permeation through the membrane. The rate of permeation depended on the osmotic properties of the solute, such as the molecular size and the presence of colloidal species. The extraction equilibrium was established by the solvent‐extraction properties of the solute in each system, and the equilibrium was approached through the cellulose membrane by a first‐order kinetic process. The method appears to be useful for ‘packaging’ organic solvents in membrane containers to be used for extractions in which time is not a factor. In certain cases, equally well extracted solutes, such as zirconium and aluminium 8‐hydroxyquinolates, can be separated because one solute exists as a partially colloidal material [Zr(IV)] and hence does not pass through the membrane rapidly.
Formation and surface properties of electron‐emissive coatings IV. DTA, ETA and dilatometry studies on some alkaline–earth hydroxides
Authors: Judd M. D. , Pope M. I.
Published: July 2010

The decomposition under vacuum of the hydroxides of calcium, strontium and barium was investigated by differential thermal analysis (DTA), electrothermal analysis (ETA) and dilatometry.

The results suggest that the rate of sintering of calcium oxide is initially governed by the formation of a pseudo‐hydroxide lattice; rapid sintering occurs only after conversion of this to the true oxide. Compacts of the oxides of strontium and barium show a remarkable resistance to sintering at temperatures up to 1000°. It is proposed that the sintering may have been inhibited by the presence of trace amounts of calcium oxide and strontium oxide formed by decomposition of impurities present in the samples of strontium and barium hydroxides, respectively.
Measurement of rate of anion exchange and the effect of organic fouling
Authors: Wall H. K. , Wakelin L. P.
Published: July 2010

A method has been developed for the examination of rates of reaction of a strongly basic ion‐exchange resin with a large organic anion.

The results indicate that an organically fouled resin reacts at a slower rate than an unfouled one under standard conditions, and the possibilities of using the method as an aid to solving the problem of organic fouling are discussed.
Assay‐increment and solubilisation of α‐glucosidase and invertase in disruption of brewers' yeast
Authors: Wiseman A. , Jones P. R.
Published: July 2010

A variety of disruption techniques were used on brewers' yeast with subsequent estimation of the additional (assay‐increment) α‐glucosidase and invertase made accessible to p‐nitrophenylglucoside (PNPG) and sucrose, respectively, in the total disruptate. The extent of actual solubilisation of these two enzymes in the 0.75 M potassium phosphate buffer (pH 6.5) present, was also measured.

Extensive release (i.e. solubilisation) of α‐glucosidase was achieved using ultrasonication or ethyl acetate autolysis, and here differential release of α‐glucosidase over invertase was large. Extensive release of both α‐glucosidase and invertase was obtained with snail gut enzyme and toluene (papain) autolysis, while air drying released some invertase but destroyed 80% of the α‐glucosidase.

The assay‐increment, over intact yeast values, for α‐glucosidase in total disruptate, which is due to increased accessibility of PNPG to this enzyme, was high for salt autolysis and toluene (papain) autolysis but was low for the Mickle shaker and the Potter‐Elvehjem homogeniser. No increment was observed using the X‐press, although solubilisation of α‐glucosidase was moderately good.

Increment, over intact yeast values, for invertase assay in total disruptate was highest with ultra‐sonication and air drying, but was nevertheless generally low owing to almost complete availability of this cell wall enzyme for assay—but not for isolation—in intact yeast.
Self‐detergence of raw wool. II. Nature and source of the detergent
Authors: Jones G.
Published: July 2010

The nature and source of the detergent substances in raw wool were studied. They were found to consist of fatty acids and acidic low polyesters and were not obtained from suint, the product of the sudoriferous glands.
Chemistry of by‐product gypsum and plaster III.—Retarder insensitivity in hydrating calcium sulphate β‐hemihydrate
Authors: Kitchen D. , Skinner (deceased) W. J.
Published: July 2010

A study has been made of the effect of fluoroaluminium ions on the retarded hydration of calcium sulphate β‐hemihydrate brought about by amino acid retarders. If sufficient fluoroaluminium ions are present (∼0.02–0.03% Al as co‐crystalline AlF2−5 in the hemihydrate), the hemihydrate becomes insensitive to retarder addition because the latter forms stable chelates with the fluoroaluminate ions. The retarder is thus effectively deactivated because the chelates are not sufficiently strongly adsorbed on to the faces of the growing gypsum crystals to influence the rate of advance of the growth steps.
Solubility of hydrogen chloride in ethers. Measurement of vapour pressures and infra‐red studies of ether‐hydrogen chloride solutions
Authors: Kapoor K. P. , Luckcock R. G. , Sandbach J. A.
Published: July 2010

Values of the solubilities of hydrogen chloride in 21 ethers over the range ‐ 75°to + 30°c at 1 atm are given. It has been found that solubilities are controlled by both inductive and steric factors. Vapour pressures of hydrogen chloride in methyl and ethyl n‐butyl ethers have been measured, and these results have been used to calculate differential heats of solution. Preliminary results are given for infra‐red shifts of ether‐hydrogen chloride complexes.
Barium aluminate hydrates I. General survey and preparative methods
Authors: Ahmed A. H. M. , Dent Glasser L. S.
Published: July 2010

The conditions of formation of the barium aluminate hydrates have been reinvestigated, and new compounds in this system are reported. Preparative methods used included reaction of barium hydroxide solutions with aluminium wire and with various forms of hydrated alumina and also reactions of mixtures under hydrothermal conditions. The methods used for the investigation and characterisation of the products are described.
Barium aluminate hydrates II. BaO.Al2O3.H2O or 1.1 BaO.Al2O3.H2O
Authors: Ahmed A. H. M. , Dent Glasser L. S.
Published: July 2010

The compound of approximate formula BaO.Al2O3.H2O has been synthesised. Infra‐red and X‐ray studies suggest a structure based on a framework of AlO4 tetrahedra. Thermal dehydration and differential thermal analysis curves are presented, and are explained in terms of the suggested structure.
Rates of low‐temperature dehydration of montmorillonite and illite
Authors: Sh. Mikhail R. , Guindy N. M.
Published: July 2010

The kinetics of the isothermal dehydration of the clay minerals, montmorillonite and illite, were studied in vacuo as well as in the presence of a constant water vapour pressure. The dehydration followed a first‐order law, and the presence of water vapour led to (i) an increase in the extent of dehydration, compared with that in vacuo; (ii) a retardation to the rate of dehydration; and (iii) a great increase in the energy of activation required for the dehydration.

Dehydration in vacuo appears to be diffusion‐controlled with an activation energy of 2–4 kcal/mole, whereas the desorption of water appears to control dehydration in the presence of water vapour, with an activation energy of 12–15 kcal/mole. The results are discussed in conjunction with the mechanical contraction of the layer structure, and the introduction of diffusion barriers when dehydration in vacuo takes place.
Continuous production of high‐purity water by electro‐deionisation
Authors: Matějka Z.
Published: July 2010

Operating conditions were investigated for a packed‐bed membrane cell for electro‐deionisation of brackish or tap water to give high‐purity water with electrical conductivity of the order 0.1 μmho/cm. Flow rates of 10–40 h−1, current densities of 0.5–5 mA/cm2, and incoming solution concentrations of up to 0.01 N were used. It was shown that strongly acidic cation‐exchange resin plus strongly basic anionexchange resin in volume ratio 1:1 was the most effective, and that particle size needed to be 60–80 mesh and resin bed thickness 3 mm for optimum current efficiency in purifying water to the required standard.
Kinetics of absorption of isobutylene in acetic acid
Authors: Gehlawat J. K. , Sharma M. M.
Published: July 2010

The kinetics of absorption of isobutylene in acetic acid in the presence of concentrated sulphuric acid (98 wt.‐%) as catalyst, which results in the formation of t‐butyl acetate, was studied in a 10‐cm i.d. agitated glass reactor. The solubility of isobutylene in acetic acid and t‐butyl acetate was determined experimentally. The reaction is relatively slow and the diffusional factors could be completely eliminated. The values of the second‐order reaction rate constant were 0.82 and 2.7 cm3 mole−1 sec−1 at 20° and 40°c, respectively.
Correlation for helium solubilities in liquids
Authors: Marathe V. V. , Prausnitz J. M.
Published: July 2010

An approximate correlation for the solubility of helium in a variety of solvents over a wide range of temperatures is presented.
Silver rubidium iodide solid electrolyte
Authors: Scrosati B.
Published: July 2010

Silver rubidium iodide (RbAg4I5) is a unique solid electrolyte because of its extremely high conductivity which has an almost negligible electronic contribution. This characteristic makes RbAg4I5 a very promising electrolyte for the development of high‐power solid‐state batteries. Consequently, a considerable amount of work has been carried out on this compound since its discovery in 1967. In the first part of this paper the physicochemical and electrochemical properties of this electrolyte are reviewed, and then the characteristics and performances of RbAg4I5 solid‐state cells are discussed.
Kinetics of the iron(III)‐catalysed oxidation of oxalate by permanganate
Authors: Mapstone G. E.
Published: July 2010

The method of reaction times has been used to investigate the kinetics and mechanism of the iron‐catalysed reaction between permanganate and oxalic acid.

The rate‐controlling step is the decomposition of the dioxalatoiron(III) ion.

The reaction rate is independent of the initial permanganate concentration below 0.0015 N but is proportional to the initial concentration above 0.002 N. The rate equation for the reaction at 24°c is dx/dt= −(9.9 × 10−3 a+ 1.8 × 10−5[Fe3+]1/3).[H2C2O4]2/3 where a is the initial permanganate concentration.
Self‐heating and ignition of chemically activated carbon
Authors: Bowes P. C. , Cameron A.
Published: July 2010

Following the occurrence of fires in chemically activated carbon in transit, a study has been made of the self‐heating and ignition properties of this material.

Thermal ignition theory has been applied to the results of laboratory scale self‐ignition experiments and has enabled realistic prediction of critical sizes of pile for self‐heating to ignition at ordinary ambient temperatures. However, predictions of times to ignition at ordinary temperatures are much larger than found in practice.

A distinction emerges between a long‐term self‐heating process responsible for the observed ignition of the ‘weathered’ carbon and short‐term processes which probably include the establishment of moisture equilibrium with the atmosphere and which are largely completed during the standard ‘weathering’ time of 8 days. The long‐term process is not affected by this weathering but is dependent on the temperature of carbonisation and weathering at elevated temperatures (e.g. 100°C).

Safe carriage of the carbon in economically worthwhile quantities is ensured by packing in polyethylene bags. These can sustain a small amount of damage with impunity.
Deposition of primary kainite from marine bitterns in solar evaporation
Authors: Choudhari B. P.
Published: July 2010

Mother liquor compositions during the solar evaporation of marine bitterns have been compared with corresponding isothermal equilibria in the NaCl‐KCl‐MgCl2‐MgSO4‐H2O system. The compositions indicate that on solar evaporation of bitterns, potassium is deposited solely in the form of kainite, and that co‐deposition of free sylvite and epsomite does not take place. It is also shown that during solar evaporation, the concentration of potassium is relatively low and that of magnesium relatively high, resulting in a more efficient precipitation of potassium in solar evaporation than in the forced or isothermal evaporation of sea water or of pure salts.
Reactions of unsaturated compounds II. Structure and chromic acid oxidation of the hydrocarbon C19H22 obtained by the dehydration of 1,1‐diphenyl‐2‐ethyl‐2‐methylbutan‐1‐01
Authors: Moussa G. E. M. , Eweiss N. F.
Published: July 2010

Dehydration of 1,1‐diphenyl‐2‐ethyl‐2‐methylbutan‐1‐01 gives a hydrocarbon C19H22 which was identified as 3‐ethyl‐4,4‐diphenylpent‐2‐ene.

Oxidation of C19H22 with chromium trioxide in acetic anhydride gave acetophenone, benzophenone and α,α‐diphenylpropionic acid. Oxidation with chromium trioxide in aqueous sulphuric acid gave 2,2‐diphenylpentan‐3‐one, benzophenone and benzoic acid.

A tentative explanation for the production of abnormal fission products is given.
The formation and surface properties of electron emissive coatings VIII. Structure of strontium‐barium double carbonates
Authors: Judd M. D. , Pope M. I.
Published: July 2010

The double carbonates of strontium and barium SrxBa2‐x(CO3)2 have been shown to undergo, on heating, a transition from an orthorhombic to a hexagonal crystal form. The temperature at which this phase change occurs, and the heat required for the transition, are dependent on the value of x.
The reversed two‐environment model of micromixing and growth processes
Authors: Tsai B. I. , Fan L. T. , Erickson L. E. , Chen M. S. K.
Published: July 2010

A reversed two‐environment model of micromixing in a flow reactor in which the feed enters a maximum mixedness environment and then passes to a segregated environment is presented. The performance equations for an arbitrary residence time distribution are developed and employed to analyse the behaviour of growth processes in a continuous stirred tank reactor under intermediate states of micromixing. The results, which are bounded by the two extremes of micromixing, indicate that micromixing is important in growth processes and that segregation appears to reduce the rate of cell production.
The preparation and hydrolysis of silicon isopropoxides
Authors: Emblem H. G. , Fothergill E. W. , Hargreaves K.
Published: July 2010

The preparation of tetraisopropoxysilane by the liquid phase reaction between tetrachlorosilane and isopropanol is described, together with the preparation of ‘isopropyl silicate’ by treating tetrachlorosilane or crude tetraisopropoxysilane with a mixture of isopropanol and water in which the molar ratio SiCl4: H2O is less than 1:1. This ‘isopropyl silicate’ is a mixture of tetraisopropoxysilane and isopropoxypolysiloxanes. The formation of isopropoxypolysiloxanes from pure tetraisopropoxysilane saturated with hydrogen chloride is also described. The hydrolysis of silicon isopropoxides is discussed. Under suitable conditions, hydrolysates which may be used to bind powdered refractories can be obtained.
The synthesis of barium hexaferrite from iron oxide and barium carbonate: 1. General features of the reaction
Authors: Bye G. C. , Howard C. R.
Published: July 2010

The reaction between BaCO3and Fe2O3in the proportions necessary for the formation of the hexaferrite has been studied in air. The decarbonation reaction was followed by measuring weight loss isothermally, the formation of hexaferrite by measurement of saturation magnetisation and by X‐ray diffractometry.

The only kinetically important intermediate found was the monoferrite and its rate of formation could be correlated with the rate of decarbonation. An unexpected feature of this process was the rapid apparent disintegration of the barium carbonate lattice: this was far more rapid than the weight loss suggested.

An examination of the pseudobinary system BaO‐Fe2O3in air at 1000°C using the electron micro‐probe analyser on reaction products at an interface between partly reacted Fe2O3and BaCO3revealed the high barium ferrites 2BaO.Fe2O3; 3BaO.Fe2O3; 5BaO.Fe2O3but no compound intermediate in composition between mono‐ and hexaferrite, nor any solid solution of Fe2O3in monoferrite.

With powdered reactants the high barium phases were not formed in sufficient concentration and or crystallinity to be revealed by X‐ray diffraction. But their presence could be inferred, because of their reaction with water vapour and/or carbon dioxide, from infrared (i.r.) absorption in the range 700–900 cm−1. An absorption peak at 880 cm−1appeared to be associated with a very small amount of incompletely reacted material as saturation magnetisation approached the maximum achievable.

In the presence of only 0.5% lithium fluoride both decarbonation and the conversion of mono‐ to hexaferrite were greatly accelerated; scanning electron microscopy revealed a big change in crystal size and the form suggested a mechanism involving a liquid phase.
Sorption of benzene by Kenya diatomite
Authors: Odhiambo D. , Desai N. C.
Published: July 2010

Samples of Kenya diatomite were washed with dilute hydrochloric acid and both untreated and acid‐treated samples then heated to various temperatures. Benzene adsorption isotherm on each sample was determined at 25°c. Hysteresis occurred in all the isotherms except isotherms on diatomite preheated at 1000°c. The suitability of these isotherms for BET surface area calculation has been examined. For the untreated and acid‐treated samples which were not preheated, the pore‐size distribution and pore‐volumes have also been calculated from the isotherms.
The evaporation of fruit juices
Authors: Robbins R. H. , Gresswell D. M.
Published: July 2010

An historical introduction to the production of fruit juices and their concentrates is provided. The introduction of modern evaporative techniques is examined. The storage properties of concentrates and the evaporation of citrus juices is discussed. It is concluded that with high initial juice quality and the use of volatile recovery satisfactory fruit juice concentrates can be produced by all evaporator types, although those with short residence times give the best effects on flavour except in certain special cases.
The centri‐therm evaporator and its application to heat sensitive foods
Authors: Shinn B. E.
Published: July 2010

A description of the theory of the Centri‐Therm evaporator is given, together with illustrations of the parts. The application of the evaporator to a number of heat sensitive foodstuff liquids is examined. Comparison of the cost of operation of the Centri‐Therm evaporator with other comparable evaporation methods is provided.
Organic polysulphides in town gas: II. The chemistry of the mercaptan/sulphur reaction
Authors: McGrath L. , Prebble K. A.
Published: July 2010

The mechanism of the lime‐catalysed reaction between alkyl mercaptans and elemental sulphur has been investigated, and is found to be essentially the same as that of amine‐catalysed reactions. From the following and other reported results, the reaction is interpreted in terms of electron delocalisation by pπ‐dπ orbital overlap in sulphur chains, leading to predictable, ordered, stepwise nucleophilic degradations of these sulphur chains.

The appearance of polysulphides during the dry‐purification of town gas (to remove hydrogen sulphide) results from mercaptan/sulphur reactions; the present study indicates that, under conditions existing in dry‐purification systems, it is not possible to interfere with these reactions and thus prevent polysulphide formation.
4‐Fluoro‐3‐nitroaniline and its N‐substituted derivatives
Authors: Bil Milos S.
Published: July 2010

4‐Fluoro‐3‐nitroaniline has become of significant importance in the U.S.A. as a novel dye intermediate. Its use for pharmaceuticals, insecticides, and more dyes might soon be extended. Preparations of its various N‐substituted derivatives are briefly reviewed in this article.
A study of the growth mechanism of calcium carbonate in the carbonatation process for refining of raw sugar
Authors: Kelly F. H. C. , Keng Mak Fong , Sim Chua Gek
Published: July 2010

A study of the size distribution of calcium carbonate particles obtained by precipitation in a sucrose medium containing different polar additives has been made, including a series of tests to determine the polar property of the precipitate surface via electrophoresis and measurements of heat of adsorption. A mechanism of polar growth has also been suggested to explain the present results.
The reduction of ferric chloride by aluminium in aluminium chloride melts
Authors: Foley E. , Moyle F. J.
Published: July 2010

The rate of reduction of FeCl3 to FeCl2 by metallic aluminium in AIcl3 melts has been studied at 212, 227 and 242 °C. Within the range of conditions investigated, the rate of reduction was proportional to the ferric ion concentration in the melt and to the surface area of the aluminium. After an initial coverage of the aluminium by a protective film of iron the reduction proceeded effectively only to the ferrous state.
Influence of the conditions of preparation on the texture of some silica gels
Authors: Girgis B. S.
Published: July 2010

Silica gels were prepared at pH values varying from 1.5 to 8, and at temperatures of 20 to 90 °C. Specific surface areas were evaluated from the nitrogen adsorption isotherms, employing the BET method, t‐plots, αs‐plots, and Kiselev's integrai equation. Pore‐size distributions as well as cumulative surface areas were determined by the procedure of Cranston and Inkley. An increase in pH causes a decrease in the specific area, and an increase in both the mean pore radius and pore volume of the xerogel. An increase in the BET'S C value appeared with an increase in the mean pore radius and the number of OH‐groups (NOH) of the material.
Kinetics of oxidation of 2‐methylpropene over chlorine modified copper oxide catalyst
Authors: Mann R. S. , Yao K. C. , Dosi M. K.
Published: July 2010

The vapour phase air oxidation of 2‐methylpropene to methacrolein over a copper oxide catalyst supported on pumice, modified by a continuous supply of chlorine, was investigated in an isothermal integral flow reactor at atmospheric pressure between 300 and 450 °C. The effects of several variables, weight ratio of modifier (CI) to 2‐methylpropene in the feed, feed ratio of oxygen to 2‐methylpropene, reaction temperature and the reciprocal of space velocity on the conversion and product distribution were determined by gas chromatography. The results indicate that the promotional effect of the modifier is mainly due to successful suppression of further oxidation of aldehyde to undesired products. Though several mechanisms were postulated, the rate of reaction was most satisfactorily correlated by a mechanism, which assumes the rate controlling step to be the surface reaction between charged adsorbed 2‐methylpropene and oxygen.
A study of the thermal decomposition of ammonium nitrate using a gas chromatographic technique
Authors: Bennett D.
Published: July 2010

The thermal decomposition of ammonium nitrate and associated mixtures in the range 170 to 200 °C has been studied by measuring the rate of evolution of nitrous oxide using a flow system in conjunction with a gas chromatograph enabling measurements to be made at temperatures of practical importance not covered in most previous investigations. The rate constant calculated from the data for pure ammonium nitrate was compared with the values of other workers.

The effects of water and of monoammonium phosphate on the decomposition rate were studied. The effect of several metal ions on the decomposition rate was also studied, but no clear pattern emerged from the results.
The feasibility of a new method for maintaining clean conditions in once‐through boilers
Authors: Turner D. J.
Published: July 2010

A method of using chelating agents for maintaining clean conditions in once‐through boilers is considered in detail. It involves forming volatile, inner complexes with unwanted oxide material so that the metal ions can be carried through the turbine and, after condensation of the steam, be removed by ion exchange. Potentially suitable agents are considered from the point of view of thermal stability and corrosion risk; also thermodynamic stability and volatility of their complexes. Most chelating agents available in commercial quantity appear to be unsuitable but oxine (8‐hydroxy quinoline) at least, seems satisfactory and worth investigating further. Oxine, along with certain other aromatic chelating agents, should be able to prevent the formation of metal‐oxide debris in high pressure drum boilers.
Thermodynamics of interaction of acetylene with cuprous ion in an aqueous medium
Authors: Natarajan G. S. , Venkatachalam K. A.
Published: July 2010

Thermodynamic data for formation of Cu.C2H2+ and Cu+.C2H‐ complexes in aqueous CuCl‐NH,Cl‐HCl medium have been obtained by the potentiometric technique. The data are of interest in homogeneous liquid phase catalytic conversion of acetylene to various products.
A new method for the preparation of tetraiodophthalic anhydride
Authors: Hashem A. I.
Published: July 2010

A new method for the preparation of tetraiodophthalic anhydride is presented and discussed.
A study of some intermolecular interactions between organic dye molecules in aqueous solution by fluorescence quenching and difference absorption spectrophotoinetry
Authors: Owen E. D. , Sultana Q.
Published: July 2010

Intermolecular interactions between the fluorescent organic dyes Fluorescein, Fluorescein Diiodide, Eosin, Rose Bengal, Erythrosin, Phloxine, Phloxine B, Rhodamine 6G, Lissamine Rhodamine B200 and the non fluorescent Crystal Violet and Malachite Green in aqueous solution have been studied by fluorescence quenching and difference absorption spectrophotometry. Equilibrium constants for the interactions have been determined by the two techniques mentioned and are compared. Absorption and fluorescence spectra and rates of photolysis of solutions obtained by extracting aqueous solutions of the mixed dyes into organic solvents are described.
Dielectric and thermodynamic behaviour of some monohydric alcohols in dioxane and cyclohexane
Authors: Sakellaridis P. , Hinopoulos B.
Published: July 2010

The dielectric and thermodynamic behaviour of some monohydric alcohols in their dioxane or cyclohexane solutions is investigated in the microwave frequency region as a function of concentration and temperature.

It has been found that the relaxation time decreases monotonically on the addition of dioxane. This behaviour is different from that found previously by similar measurements on alcohol‐heptane solutions and in the present investigation on ethanokyclohexane solutions. The results are discussed in relation to the chemical structure.

Computation of the experimental data by a polynomial curve fitting programme has resulted in analytical relationships between the relaxation time variation and the concentration.
The effect of heat treatments on the semiconductor properties of a commercially electrodeposited manganese dioxide
Authors: Foster I. B. , Lee J. A. , Tye F. L.
Published: July 2010

The temperature dependence of d.c. conductivity and thermoelectric power has been studied for a series of thermally treated samples of an electrodeposited, microcrystalline, γ‐phase MnO2. Measurements were made on samples compacted at 3.86 × 105 KN/m2. Measurements of a.c. impedance up to 50 MHz were made on the powder samples to test for particle homogeneity.

The results indicated that a hopping electron transport model was probably appropriate for these samples and that the majority carriers were electrons, possibly ionised from donor sites provided by oxygen deficiency. Conductivity, surprisingly, was found to increase in an oxygen environment and it is suggested that oxygen adsorption greatly enhances the electron mobility.

The d.c. conductivity and thermoelectric power were found to be strongly dependent on sample outgassing temperature. The former reached a maximum at about 320 °C, the latter became less negative with increasing outgassing temperature. It is tentatively proposed that carrier density and “surface” mobility increased as terminal OH groups forming strong traps on manganese sites were removed by thermal treatment.

Measurements of a.c. impedance on samples outgassed at 35 °C and 365 °C displayed dispersion around 20 MHz indicative of a high resistance surface skin possibly due to a hydroxylated and reduced surface respectively.
Dissolving pulps from Egyptian bagasse I. Effect of depithing on the chemical, physical and sub‐microscopic characteristics of viscose pulps
Authors: Abou‐State M. Amine , Helmy Samia A.
Published: July 2010

Egyptian bagasse was pulped by the prehydrolysis‐sulphate process. The effects of depithing on certain chemical, physical and sub‐microscopic characteristics of the pulp, in particular its reactivity towards xanthation, were investigated. Depithing before and after prehydrolysis was compared. Pulps with a higher degree of chemical purity and higher degree of whiteness showed better reactivity towards xanthation. However, the most important factor affecting the reactivity was the accessibility of the cellulose hydroxyls to reactant molecules.
The extraction of divalent cobalt, copper, zinc and cadmium from hydrochloric acid solutions by tri‐n‐butyl phosphate
Authors: Sato Taichi
Published: July 2010

The partition of divalent cobalt, copper, zinc and cadmium between hydrochloric acid solutions and solutions of tri‐n‐butyl phosphate (TBP) in benzene or kerosene has been investigated under different conditions. Further the absorption spectra of both the aqueous and organic phases have been studied, and the infrared spectra of the organic phases have been examined. It was found that the order of the extraction efficiency of TBP for divalent metalsis Zu > Cd > Cu > Co for [HCl]aq < 8M and Zn > Cd > Co > Cu for [HCl]aq > 8M.
Autocatalysis in calcination of powdered lead
Authors: Miyazaki K.
Published: July 2010

The kinetics of calcination of powdered lead has been studied. The oxidation of powdered lead, a non‐stoichiometric suboxide of lead, appears to be autocatalytic at an elevated temperature of 400 to 520 °C, and the end product is red lead Pb3O4. Blending powdered lead with a small amount of red lead greatly increases the rate of calcination to yield the final product Pb3O4, compared with the case of calcination of powdered lead alone.
Precipitate flotation in the treatment of metal‐bearing effluents
Authors: Pearson Douglas , Shirley Joseph M.
Published: July 2010

Flotation is proposed as an alternative to sedimentation for removing metal hydroxide precipitates formed in the treatment of effluents from metal finishing operations. A brief study has shown the effect of different parameters in the system on the metal content of the effluents. An estimate of the costs of treating effluents by this method showed it to be more costly than sedimentation; on the other hand, metals recovery may be facilitated and this would offset the higher costs.
Correlation of activity coefficients of water in solutions of sulphuric acid and toluene sulphonic acid
Authors: Saunders A. , Sawistowski H.
Published: July 2010

Equilibrium data are presented for the water‐sulphuric acid‐toluene sulphonic acid system.
Some applications of rapid gas chromatography
Authors: Cross Robert A. , Robinson Stuart C. F.
Published: July 2010

A gas chromatograph has been developed with which simple gas mixtures can be analysed rapidly, repetitive separations being possible every few seconds. The instrument operates automatically, sampling from a number of points, and it can be remotely controlled.

Changes taking place in the composition of atmospheres, flue gases and engine exhausts, which were too rapid for estimation by conventional sampling and analytical procedures, were followed without difficulty, and the results of these analyses are presented and discussed.
pH and Eh control of cultures of sulphate‐reducing bacteria
Authors: Brown Donald E. , Groves George R. , Miller John D. A.
Published: July 2010

Batch cultures of Desulfovibrio vulgaris, carried out in a 5‐litre stirred fermenter, are described. Bacterial counts and sulphide formation are reported for experiments carried out under a selection of controlled Eh and pH conditions. Specific growth and sulphide formation rates are determined and compared. Variations in the growth rates under the different controlled conditions are examined and discussed in terms of product inhibition by sulphide. A relatively high specific rate of exponential growth was observed at Eh = ‐ 150 mV and pH=6.95, when sulphide inhibition was believed to be at a minimum.
Mass transfer coefficients in mixer—settlers
Authors: Sreenivasan Krishnamurthy , Viswanath Dabir S.
Published: July 2010

Mass transfer coefficients have been determined for transfer into a highly viscous phase in a stirred tank involving high Schmidt numbers. The results have been used to compute mass transfer coefficients in the extraction of free fatty acids from oils using alcohol and show good agreement with experimental results.
Production of an amylolytic enzyme by Bacillus polymyxa in batch cultures
Authors: Griffin Patrick J. , Fogarty William M.
Published: July 2010

Growth of Bacillus polymyxa and high activities of amylase were obtained in media containing starch and peptone. Of the metals of biological significance, calcium and manganese had the most beneficial effects on enzyme yields. Control of pH was critical for the establishment of conditions which yielded maximum levels of enzyme. The appearance of highest amylase activity in culture supernatant liquors during the stationary phase of growth was not due to autolysis; intracellular levels of the enzyme were shown to be very low throughout the fermentation. When the organism was grown in a medium containing a low level of starch (1%, w/v), amylase activity was low during the logarithmic phase of growth but rose rapidly in the culture liquor when growth ceased. Negligible activity was detected when the organism was grown in a medium which contained excess starch. This amylase therefore appears to be a true extracellular enzyme, in the accepted sense. It is produced in response to exhaustion of the carbon source from the medium.
Separation of U(vi) from carbonate solutions by ion flotation
Authors: Shakir Kamal
Published: July 2010

The ability of uranyl ions to form highly charged anionic complexes with carbonate or bicarbonate anions furnishes the basis of its removal from carbonate media by cationic collectors using the ion flotation technique. In this investigation cetyl trimethyl ammonium bromide was used as collector. The extent of removal depends on many factors and removals approaching 100% could be achieved under certain controlled conditions. The factors that can affect the flotation process, viz. gas flow rate and concentrations of collector, uranium and carbonate were investigated and the best conditions were selected.
The anomalous behaviour of isoquinoline relative to quinoline and its significance in relation to structure and reactivity
Authors: Roy Sisir K. , Roy Subhash C. , Rao H. S.
Published: July 2010

Vapour phase catalytic oxidation of quinoline over a vanadia base catalyst yielded nicotinic acid, while vapour phase catalytic ammoxidation gave 3‐cyano‐pyridine, the benzenoid ring undergoing cleavage in both cases. The isomeric molecule, isoquinoline, was however found to behave in sharp contrast, undergoing an unexpected reaction in its transformation into phthalimide during identical conditions of oxidation and into ortho‐phthalonitrile during ammoxidation, the pyridine ring undergoing cleavage in both cases, with the appearance of the heterocyclic ring nitrogen in a reactive functional group. The significance of these observations is discussed in relation to structure and reactivity and possible reaction mechanisms are suggested.
The thermal decomposition of pure and doped cadium carbonate: I. Kinetics
Authors: Mikhail R. Sh. , Dollimore David , Kamel A. M. , El‐Nazer N. R.
Published: July 2010

The thermal decomposition of both pure and doped cadmium carbonate has been studied. Doping was effected by adding 1, 5 and 10 atom‐% of Al3+, Li+, Zn2+, Ca2+, and Ba2+. Differential thermal analysis, as well as the kinetics of isothermal decomposition of the various carbonates, has been investigated between 310 and 560 °C. The decomposition of both the pure and doped samples was found to obey Mampel's theory. Rate constants were evaluated and found to be appreciably affected by the presence of foreign ions. Application of the Arrhenius equation gave an activation energy of 22.5 kcal/mol for pure cadmium carbonate which is comparable with the standard enthalpy of the reaction which is 22.0 kcal/mol. On the other hand, in applying the Arrhenius equation to the rate constant of the doped samples, no straight lines could be obtained indicating a continuous decrease in the activation energy with a rise of temperature. The activation energies were found to vary between 4.0 and 44.0 kcal/mol. Discussion is presented to account for the effect of the various dopes on the mechanism of thermal decomposition.
Dissolving pulps from Egyptian bagasse. II. Low temperature cooking
Authors: Amine abou‐state M. , Awad Boshra M. , El‐Morsy M. Mossad
Published: July 2010

Bagasse was pulped by the prehydrolysis‐soda process. Increasing the concentration during prehydrolysis or pulping had a favourable effect on pulp properties. Further improvement in these properties was attained when the increase in concentration was accompanied by lowering the temperature. The effects of increasing the concentration and lowering the temperature of prehydrolysis and pulping were compared.
High purity cyclohexane from petroleum streams by extractive distillation
Authors: Tripathi Raghunath P. , Sagar Jatinder M. , Gulati Indar B.
Published: July 2010

In view of the high cyclohexane content (1.81 wt‐%) of one of the Indian crude oils, a systematic study on the production of high purity cyclohexane from a suitable refinery stream was undertaken at the Indian Institute of Petroleum. Superfractionation of the refinery stream followed by extractive distillation of the resulting concentrate, with aniline as solvent, gave cyclohexane product of 99.0% purity in a continuous bench scale operation. The solvent free extract does not need any refractionation step for producing cyclohexane of the above purity.
Polymerisation of bicyclohepta‐(2,5)‐diene with palladium‐π‐complexes
Authors: Hojabri Fereidun
Published: July 2010

A pinene‐π‐allylic complex of palladium was capable of catalysing the polymerisation of bicyclohepta‐(2,5)‐diene. Polymerisation pattern was the same as in the case of PdCl2, i.e. only one double bond of the diene was opened by this reaction. The optimum temperature range for the polymerisation was between 130 and 200 °C. Polar solvents retarded the reaction.

The Pd‐π‐allylic complex, for the polymerisation of the same olefin, was a more active catalyst than other palladium compounds (e.g. PdCl2).
Flotation of phosphorus(V), molybdenum(VI), and rhenium(VII) oxyanions
Authors: Charewicz Witold
Published: July 2010

Efficiency and intensity of the flotation of isostructural, tetrahedral oxyanions with the cationic (R)4N+ type surfactant were examined, exemplified by the case of the diluted aqueous solutions of phosphorus(v), molybdenum(vi) and rhenium(vii) at concent rations of 1 × 10−4, 5 × 10−5 and 1 × 10−5 kmol m−3. No direct relation was found between the flotation efficiency and the charge and size of the examined ions. For ions of equal charge, the Grieves entropy criterion15 was obeyed in most cases.
Kinetics of oxidation of propionaldehyde
Authors: Gurumurthy Coimbatore V.
Published: July 2010

The kinetics of the oxidation of propionaldehyde by oxygen in the presence of manganese propionate catalyst, in a batch reactor are reported. Experiments are designed to yield a mathematical description of the process. Reaction rate constants are obtained from pattern search technique.
The composition of the binding material in calcium silicate bricks
Authors: Purton Michael J.
Published: July 2010

Results from the chemical analyses of commercial calcium silicate brick samples are presented. The composition of the binding material in the bricks is consistent with the formation of CSH(I). The strength of the bricks appears to be related to the proportion of voids filled with cementing material.
Pulp and paper from corn stalks, II
Authors: Abou‐State M. Amine , El‐Masry Ahmed M.
Published: July 2010

Pulps with the same chemical characteristics were prepared by carrying out the pulping process either under atmospheric pressure or under high pressure. Atmospheric pressure pulping had a highly favourable effect on the strength properties of paper in contrast to high pressure pulping. The effects of the pith fraction, the stems and the leaves on the chemical composition and the physical strength characteristics were investigated.
The vapour‐liquid equilibrium of ternary systems with limited miscibility at atmospheric pressure
Authors: Van Zandijcke F. , Verhoeye L.
Published: July 2010

The complete study of the vapour‐liquid equilibrium of ternary systems with limited miscibility requires vapour‐liquid equilibrium determinations and liquid‐liquid equilibrium determinations at boiling point. The vapour‐liquid equilibrium was determined by means of an equilibrium still based on the principle of Giilespie but modified in such a way that an accurate boiling point measurement, even for systems with heterogeneous liquid was possible and that the vapour phase was analysed without previous condensation. Two ternary systems have been studied: the system methanol‐ethylacetate‐water and the system ethanol‐ethylacetate‐water. The ternary data have been predicted by means of the equation of Renon and Prausnitz. The parameters are determined by correlating the binary data. The ternary vapour‐liquid equilibrium are predicted within 1‐2. 10 −2 mol fraction for the vapour composition and 1°C for the boiling point. The position of the predicted tielines of the liquid‐liquid equilibrium at boiling point was almost coinciding with the position of the experimental tielines. There was a slight deviation of the predicted and experimental binodal.
Organophosphoryl ethanolamine analogues II. Synthesis of methyl‐N,N‐dipropyl and piperidyl phosphonamidic acid esters
Authors: El‐Deek M. , El‐Yazid A. Abou
Published: July 2010

A series of phosphonamidic acid esters, containing ethanolamine analogue moieties, P‐O‐CH2CH2NRR1, have been synthesised, as potential anticholinesterases. The infra‐red spectral data confirm the chemical structure of the prepared compounds.
Kinetics of hydrogen chemisorption on supported molybdenum disulphide
Authors: Samuel P. , Yeddanapalli L. M.
Published: July 2010

Chemisorption of H2 on MoS2‐Al2O3 catalyst was studied at different temperatures and initial pressures. The results when analysed according to the Elovich equation revealed multiple kinetic stages. Assigning two sets of boundary conditions to the equation, a statistical procedure employing least square analysis has been applied for the evaluation of the Elovich parameters a and α and their temperature dependence has also been followed. A comparison is made with the parameters derived by the graphical method. The role of initial surface saturation q0 on the sequence of the multiple kinetic stages is discussed. Excepting for descriptive purposes, the kinetic stage connotation is not strictly followed. On the other hand, all the first straight line portions of the Elovich plots for a given initial pressure including the single stage plots have been grouped together and the corresponding a and α were calculated. The merits of deriving the apparent activation energies from the initial rates rather than from α are discussed.
Effect of various steps of purification on ash content and ash constitution of cellulose. I. Cellulose prepared from cotton linters
Authors: Shahine Salah , El‐Shorbani Salah , El‐Sadani Mohamed
Published: July 2010

The effect of the various steps of purification on the ash content and ash constitution of cellulose prepared from cotton linters has been examined. After each step of purification, samples were analysed for total ash, SiO2, Ca, Mg, Fe, Al, Cu and Mn. Two methods of bleaching were investigated. The first involves double treatment of cellulose with sodium hypochlorite solution, and the second one treatment with hypochlorite followed by another treatment with sodium chlorite solution. The second method has a better effect in diminishing the ash content.
Reaction kinetics and mass transfer in glucose isomerisation with collagen‐immobilised whole microbial cells
Authors: Saini Rakesh , Vieth Wolf R.
Published: July 2010

Stable and active derivatives of collagen‐immobilised whole microbial cells containing glucose isomerase have been successfully prepared. The degree of crosslinking, swelling behaviour, and hydrophile/hydrophobe ratio of the complex was examined, since these factors could have a strong influence on the diffusional characteristics of the membrane. The studies on efficiency of glutaraldehyde tanning and its effect on the activity of the immobilised cells provided the connecting link between the network properties and the mass transfer effects. The catalytic pathway for the reversible enzymatic conversion of glucose to fructose has been elucidated by developing a kinetic model capable of describing the observed data over the entire range of substrate concentrations. In arriving at this model, we have also found that the bulk phase mass transfer limitations are negligible. Regarding the internal transport resistance, it has been determined that the effectiveness factor is between 0.95 and 1. A reactor design equation incorporating activity, packing density, and contact efficiency correction factors has been developed. Based on this equation, computer simulations of continuous reactor operation were performed to generate concentration–space time profiles. The model was verified experimentally and a close agreement between the predicted and observed values corroborated the correctness of the proposed bioreaction mechanism, the rate expression, and the design equation. The kinetics of a competing side reaction were found to be too slow to influence significantly the overall results.