bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic relationship of coal hydrogenation, pyrolysis and dissolution
Authors: Wiser W. H. , Anderson L. L. , Qader S. A. , Hill G. R. 
Published: July 2010

AbstractData are presented concerning the production of gaseous and liquid products from coal. The processes considered include pyrolysis, dissolution in solvent with and without the application of ultrasonic energy, batch hydrogenation, and continuous hydrogenation. The products are compared with respect to both quantity and type. Activation energies are presented and mechanisms discussed. Coal hydrogenation in the presence of an appropriate catalyst shows very great promise as a means of converting coal to liquid and gaseous fuels. Yields of 30% high octane gasoline, 5% diesel oil, 35% high Btu gas, and 30% char, on a weight basis, have been achieved.
Comparison of isothermal adsorption data by the technique of absolute adsorption
Authors: Clough P. S. , Dollimore D. , Nicklin T. 
Published: July 2010

AbstractA method of comparing adsorption data, obtained for samples within a series and having similar surface characteristics, is described. It is shown that the surface interaction with polar molecules increases quite markedly as the polar nature of the surface changes. The use of a non‐polar molecule established that the effects observed were genuine.
Formation and surface properties of electron‐emissive coatings VI. Structure and decomposition of co‐precipitated carbonates
Authors: Judd M. D. , Pope M. I. 
Published: July 2010

AbstractThe decomposition, under vacuum, of some co‐precipitated alkaline‐earth carbonates has been further investigated by applying the techniques of differential thermal analysis (DTA),† electrothermal analysis (ETA) and dilatometry.The results supplement previous work by confirming that decomposition of double and triple carbonates proceeds in two and three distinct stages, respectively. Loss of carbon dioxide from the strontium carbonate component of a double (SrBa) carbonate leads to a breakdown in the crystal structure, forming a mixture of strontium oxide and barium carbonate. Decomposition of the barium carbonate commences before decomposition of the strontium carbonate is complete. With a triple (CaSrBa) co‐precipitated carbonate, thermal decomposition of the calcium carbonate component results in a mixture of calcium oxide with the corresponding double carbonate: DTA shows conclusively that the mixture does not contain the single strontium and barium carbonates.
Application of the B.E.T. method to differentiating manganese dioxide modifications
Authors: Kolta G. A. , Abdul Azim A. A. , Girgis B. S. 
Published: July 2010

AbstractManganese dioxide samples belonging to the α‐, γ‐ and δ‐groups have been subjected to surface area measurements (B.E.T. method) and X‐ray examination before and after heat treatment at 350 and 450°c. The change in surface area of the different samples is explained in terms of two processes which act in opposite ways, namely, creation of pores and cavities (left by the escaping water), and crystal growth. The surface areas of some local and imported natural samples of manganese dioxide as well as the β‐group have been also determined.
Mechanical properties of bitumen in relation to road performance
Authors: Dormon G. M. , Snashall H. M. 
Published: July 2010

AbstractThe importance of the flow and fracture of bitumens was investigated, and the conditions arising during the application of a dense asphalt mix and the performance in service of various asphalt surfacings were considered. Methods of measuring these properties are described.With the aid of results obtained by methods devised for the direct measurement of bitumen properties at short and long times of loading, suitable for all kinds of binders, or using results deduced by means of nomographs, it should be possible to draft bitumen specifications covering their mechanical properties in engineering terms, which will be significant from the point of view of road performance over the whole range of conditions likely to be experienced in practice.
Thermal decomposition of sodium dithionite
Authors: Flaherty B. , Bather J. M. 
Published: July 2010

AbstractThe thermal decomposition of sodium dithionite (Na2S2O4) in the solid state was investigated by differential scanning calorimetry and the exothermic heat of decomposition was determined. The effect of isothermal pretreatment at various selected temperatures on the subsequently determined decomposition temperature was studied, together with the effect of sample weight on the decomposition temperature and degree of exothermicity.
Preparation of schoenite and sulphate of potash from mixed salts obtained in solar evaporation
Authors: Choudhari B. P. 
Published: July 2010

AbstractPotassium is deposited as kainite and/or carnallite by solar evaporation of sea and inland bitterns, respectively. The solubility of this natural kainite in water was found to be at 20 g magnesium chloride per 100 g water as against at 27.5 g obtained with synthetic kainite. As a result, the equilibrium data available from conventional phase diagrams were found to be not applicable for the conversion of kainite to potassium schoenite, an intermediate product to obtain potassium sulphate. Therefore applicability of the system K2Cl2‐MgSO4‐H2O to natural kainite was investigated and equilibria in reactions in slurries and optimum yields were worked out.
Microstructure of hardened gypsum pastes
Authors: Sh. Mikhail R. , Malek R. I. A. 
Published: July 2010

AbstractSpecific surface areas and pore size distribution analysis were taken as essential parameters to explore the microstructure of hardened gypsum pastes. The hydration of gypsum plaster is essentially affected by the water/plaster ratio of the mix, and by the presence of additives which might act as retarders or accelerators to the hydration process. Affecting the microstructure would mutually lead to variations of the compressive strength of the hardened pastes, and these variations are also discussed.Results are mainly expressed in terms of the solid (measured by the extent of its specific area) to the space (pore) ratios. Dual distribution of pore sizes was observed and the two groups of pores are designed as S (small) and L (large) pores. Similarities to the microstructure of hardened Portland cement pastes are indicated. Accelerators appear to function differently from retarders, and the effects of water/plaster ratios were investigated in both cases. The results obtained may carry many significant practical implications to the future use of hardened gypsum pastes.
Studies on the autoclave dehydration of gypsum
Authors: Combe E. C. , Smith D. C. 
Published: July 2010

AbstractThe effects of some additives on the autoclave dehydration of gypsum have been determined. It was possible to accelerate the reaction by the addition of calcium sulphate hemihydrate or orthorhombic calcium sulphate to the gypsum. Plasters prepared by the sodium succinate method in the presence of the latter additive had a high water requirement and poor mechanical properties.
The catalytic dealkylation of alkylphenols at atmospheric pressure
Authors: Milnes M. H. , Dean R. E. 
Published: July 2010

AbstractA comparative survey has been made of alkaline, fluorine‐containing, and charcoal‐based materials as potential catalysts for the vapour phase dealkylation of alkylphenols. o‐Cresol was used as the feed in an initial screening, and those catalysts showing most activity were then subjected to a more detailed study using higher‐boiling feedstocks. The most interesting results were obtained using aluminium borofluoride or zinc fluoride, each on a γ‐alumina support. In addition to extensive dealkylation, these catalysts also gave rise to isomerising effects. Their activity, however, rapidly declined because of carbon deposition, but could be fully restored by heating in an oxygen/nitrogen stream. The use of metal‐impregnated charcoals gave more selective dealkylation than active charcoal alone, but the improvement did not warrant the additional cost; moreover these materials could not be revivified by conventional means. The alkaline catalysts displayed a lower level of activity and could not be completely regenerated after deactivation because of carbonation in addition to carbon deposition.
Organic polysulphides in town gas: I. The corrosion problem
Authors: McGrath L. , Prebble K. A. 
Published: July 2010

AbstractBlockage of small‐bore copper tubing in gas appliances has sometimes arisen from the presence of copper sulphide scale formed by attack on the copper by organic sulphur compounds in the gas. The sulphur compounds responsible for this attack which occurs at atmospheric temperatures, are identified as organic polysulphides, probably the lower aliphatic trisulphides and tetrasulphides, formed from mercaptans and elemental sulphur. Such reactions are shown to occur under the influence of a base catalyst such as lime, and under the conditions existing in the iron‐oxide purifying plants used to remove hydrogen sulphide from fuel gases; mercaptans are present in the gas, and sulphur in the purifying material.A colorimetric test using piperidine has been developed for determining organic polysulphides in fuel gases at concentrations below 1 part/million v/v.Some comments are given on the relevance of polysulphide formation and corrosion to the distribution of North Sea natural gas.
Design and construction of a freeze dryer incorporating improved standards of biological safety
Authors: Parker J. , Smith H. M. 
Published: July 2010

AbstractThis paper describes the design of a mobile, versatile manifold‐type freeze dryer which is sealed continuously throughout primary drying, secondary drying, ampoule sealing and in situ steam disinfection of all potentially contaminated surfaces. Construction is based upon standard components, modular in design and fully interchangeable. An all‐metal liquid nitrogen‐refrigerated vapour condenser, Pyrex glass ampoules and rigid glass‐to‐metal or metal‐to‐metal “O” ring connections are features dictated by the use of low pressure steam for in situ disinfection.The machine attains standards of biological safety and control not available with commercial freeze dryers but which would seem of considerable value to the many specialist laboratories lyophilising reference or stock samples of various microorganisms.
The self heating of commercial powdered activated carbons
Authors: Cameron A. , Macdowall J. D. 
Published: July 2010

AbstractThe self heating characteristics of a series of activated carbon samples have been studied in relation to their chemical/physical properties. It appears that ease of self heating is related to the oxygen content of the carbon on a dry ash free basis, and from this it can be shown that all carbons manufactured by the steam activation process can be considered non‐hazardous for shipping purposes.A simple test is described to differentiate between the potentially hazardous and non‐hazardous in chemically activated carbons and semi‐products.The results of this investigation are fully supported by the shipping records over the past 40 years of European carbon manufacturers who are responsible for over 50% of activated carbon shipped world wide.
The synthesis of barium hexaferrite from iron oxide and barium carbonate: II. The role of iron oxide texture
Authors: Bye G. C. , Howard C. R. 
Published: July 2010

AbstractThe texture of several samples of laboratory‐prepared and commercial iron oxide and their reactivity with barium carbonate (BaCO3.6Fe2O3) has been examined. The first stage of the reaction involves decarbonation with the formation of monoferrite and dynamic thermogravimetry was used to assess mix reactivity. While some of the variation in the behaviour of iron oxide powders could be appreciated from an examination of their texture by scanning electron microscopy and porosity determination, prediction of their reactivity was not possible. In fact the reactivity of the mix can best be considered to give an indication of the efficiency of mixing of the finer iron oxide particles with the barium carbonate. In the subsequent formation of barium hexaferrite the coarse end of the iron oxide particle size range is of primary importance since it controls the rate of completion of the reaction. The larger aggregates in an iron oxide sample can readily be detected by scanning electron microscopy but conclusions regarding reactivity may be erroneous if this coarse material is dispersed during mixing. It was shown by scanning electron microscopy that the least reactive iron oxide sample examined contained aggregates which survived the mixing process employed.
Thermodynamic properties of the benzene and n‐heptane system at elevated temperatures
Authors: Butcher K. L. , Ramasubramanian K. R. , Medani M. S. 
Published: July 2010

AbstractThe total vapour pressure and the composition of the liquid and vapour phases of the benzene and n‐heptane system have been experimentally determined under equilibrium conditions at 110, 125, 140, 155, 170, 185, 200 and 215 °C. The corresponding composition of the vapour phase was also estimated using an expression for the liquid phase activity coefficient as a function of the composition of the liquid phase. Several expressions were compared and it has been found that the three‐constant Redlich and Kister equation gave the best fit of the experimental vapour pressure data than the other equations.Comparison between the calculated and measured vapour compositions has shown a discrepancy of ymeas,—ycalc. of the order of 0.02 mol fraction or 10 times the experimental tolerance. Nevertheless, the experimental values were reasonably thermodynamically consistent.The low values of the liquid phase activity coefficients indicated that the behaviour of this particular system was not far from ideality. Also, it was found that the degree of non‐ideality decreased with the increase in temperature. The behaviour of the vapour phase was shown also to be nearly ideal.The excess Gibbs free energy of mixing was calculated, and it was found to be non‐symmetrical with mole fraction. On increasing the temperature of the system, the liquid composition corresponding to the maximum GE tended to shift to a higher benzene concentration, whilst at a fixed liquid composition, GE initially decreased and then remained stationary or increased again. This was thought to be due to differences in the molar volumes of the two components.
The electrochlorination of aliphatic hydrocarbons
Authors: Acquah F. , Kuhn A. T. , Mortimer C. J. 
Published: July 2010

AbstractReported electrochlorinations of saturated hydrocarbons have been investigated. It is concluded that the results reported can all be accounted for by homogenous processes. Various apparent discrepancies between similar conclusions reached by some researchers for the case of unsaturated aliphatic hydrocarbons and the results reported by other workers have also been resolved.
Chlorination and bromination of some aromatic compounds by means of aqua regia and hydrobromic‐nitric acid mixture
Authors: Hashem A. I. 
Published: July 2010

AbstractChlorination and bromination of a series of aromatic compounds with mixtures of nitric acid and hydrochloric or hydrobromic acids yielded chloranil and bromanil respectively. The reaction was promoted by ‐OH, ‐NH2 and ‐OCH3 groups and inhibited by alkyl, ‐CHO, ‐COOH, ‐CN and ‐NO2 groups.
Oxidation of acetaldehyde to glyoxal by nitric acid
Authors: Hotanahalli S. S. , Chandalia S. B. 
Published: July 2010

AbstractThe liquid phase oxidation of acetaldehyde or paraldehyde by aqueous nitric acid to glyoxal was investigated in a stainless steel autoclave maintained under autogenous pressure. The presence of nitrous acid was necessary for the reaction. Acetic acid and glyoxalic acid were the major by‐products. The effects of concentration of nitric acid, nitrous acid and acetaldehyde as well as temperature and period of reaction on the conversion and yield of glyoxal were studied with a view to obtaining the most suitable conditions for the production of glyoxal.
Esterification of ethylenediaminetetraacetic acid
Authors: Alner D. J. , Claret P. A. , Osborne A. G. 
Published: July 2010

AbstractThe esterification of ethylenediaminetetraacetic acid (EDTA) in a hot acidic medium gives rise to impure products. The impurities have been identified and shown to be esters of various acids: nitrilotriacetic acid; iminodiacetic acid; piperazine‐1,4‐diacetic acid; N‐methylethylenediaminetriacetic acid; N,N‐ and N,N′‐dimethylethylenediaminediacetic acids and 2‐ketopiperazine‐1,4‐diacetic acid. The reactions for the formation of these impurities are discussed and a method for the preparation of pure esters of EDTA is described. Details of some crystalline derivatives, 1H‐n.m.r. and infrared spectra of a series of esters of EDTA are presented. The determination of the molecular weights of the esters by saponification is discussed.
The oligomerisation of isoprene catalysed by nickel naphthenate and isoprene magnesium
Authors: Suga Kyoichi , Watanabe Shoji , Fujita Tsutomu , Shimada Takashi 
Published: July 2010

AbstractThe oligomerisation of isoprene catalysed by nickel naphthenate and isoprene magnesium was studied under various conditions. The use of various phosphites as donors gives cyclic dimers containing dimethyloctadiene (about 90%); in particular 1,1,1‐trishydroxymethylpropane phosphite gives trimethylcyclo‐dodecatriene selectively. The use of triphenylphosphine gives a linear isoprene trimer containing farnessene.
Fluorination in gaseous phase of carbon tetrachloride on aluminium fluoride catalyst: Kinetics and chemical mechanism
Authors: Gambaretto Gian Paolo , Avezzu Francesco , Gola Everardo 
Published: July 2010

AbstractThe fluorination in gaseous phase of carbon tetrachloride has been investigated on aluminium fluoride with the aim of defining the mechanism of the reaction on this catalyst.The reactor and the operating conditions, were chosen in such a way as to isolate the effects of diffusion analysing the single reaction steps.While for the process in liquid phase the kinetics appears to be controlled by the formation of activated complexes between carbon tetrachloride and the catalytic support, the selective adsorption of HF on the catalyst is more probably the controlling step when the reaction is carried out in gaseous phase.
Glycerolysis of methyl esters of fatty acids using molecular sieves
Authors: Barrer Richard M. , Ruiz José L. LÓPez 
Published: July 2010

AbstractGlycerolysis of the methyl esters of oleic and stearic acid has been investigated in presence and absence of zeolite 4A. By removing the methanol produced this zeolite improved the yields of glyceride substantially. Other factors studied which influenced the yields were temperature, reactant concentrations and proportions and catalyst.
The thermodynamics of fluorine loss during the chemical analysis of welding fluxes
Authors: Halstead W. D. 
Published: July 2010

AbstractThe chemistry of the solution of welding fluxes in Li2O‐B2O3 melts prior to analysis has been examined using chemical thermodynamics. A chemical model describing these melts is proposed, and using it, the particular abilities of two components of the fluxes, SiO2 and Al2O3, in facilitating loss of fluorine from the solutions, are described.
The preparation and characterisation of crystalline α‐zirconium phosphate
Authors: Horsley Stuart E. , Nowell Derek V. 
Published: July 2010

AbstractCrystalline α‐zirconium phosphate has been prepared by four methods. The products have been characterised by chemical and thermal analysis, X‐ray and infrared spectroscopy, surface area, porosity and particle size determinations and electron microscopy. A method is recommended for the preparation of crystalline α‐zirconium phosphate.
Kinetic models for the setting of plaster of paris
Authors: Taplin John H. 
Published: July 2010

AbstractA general rate equation is derived for processes such as the hydration of calcium sulphate hemihydrate in which the position of the rate maximum depends on the relative rates of dissolution and precipitation. Allowance is made for these processes to depend on powers of under or super‐saturation other than unity and for limitation of the precipitation rate by crystal‐crystal contact.The equations of Ridge and of Coombe et al. have the rate maximum fixed at 60 and 28 % respectively due to inadequate derivation, however they are both readily fitted by the general equation.
The thermal decomposition of pure and doped cadmium carbonate: II. Surface and pore structure studies
Authors: Mikhail R. Sh. , Dollimore David , Kamel A. M. , El‐Nazer N. R. 
Published: July 2010

AbstractSpecific surface areas and pore structure studies were carried out on pure and doped cadmium carbonate heated at different temperatures. Doping with a different valency cation than the host ion was found to influence appreciably both the extent and location of the surface. Results could be interpreted in terms of anion vacancy mechanism, in which these vacancies could be created in the case of Li+ doping and could be annealed in the case of Al3+ doping, thus affecting “material” transport which in turn is reflected in changes in the extent and location of the surface. In this respect Al3+ ions might act as “inhibitors” for material transport and thus lead to a “stabilised” pore structure. The results implicitly suggest that “material” transport is more significant in affecting the pore structure than changes in the rates of isothermal decomposition.
Liquid phase oxidation of cyclohexanone to adipic acid by air in acetic acid solution
Authors: Kamath Sharatchandra S. , Chandalia Sampatraj B. 
Published: July 2010

AbstractThe liquid phase oxidation of cyclohexanone to adipic acid by air in the presence of acetic acid as a solvent and cobalt acetate or manganese acetate as a catalyst was investigated at a temperature of 60 to 100 °C, and at essentially atmospheric pressure. Succinic acid and glutaric acid were the major by‐products. Under the most suitable set of conditions (cyclohexanone, 1.2 M; cobalt acetate, 7 × 10−3 M; superficial air velocity, 2.5 cm/s, temperature, 80 °C; period of reaction, 5 h), the overall conversion of cyclohexanone was 61 % and the yield of adipic acid and diabasic acids was 69.3% and 85.6% respectively.
High‐pressure steam curing of high‐slag cement: I. Composition of the hydrated cement
Authors: Kamel Abdel‐Aziz H. 
Published: July 2010

AbstractThe phases formed in a high‐slag cement on curing in saturated steam at 180 lbf/in2, have been investigated. X‐ray diffraction revealed that in the presence of suitable addition of fine quartz, 11‐Å tobermorite was the predominant phase formed in an autoclaving period of 5 h at maximum pressure; the phases identified in neat slag cement were 11‐Å tobermorite and hillebrandite. The same phases were identified in the samples autoclaved for 6 h, in addition to minor amount of xonotlite. Chemical analysis of the same hydrated samples has shown that the molar CaO/SiO2 ratio was 1.27 for the cement‐quartz and 1.49 for the neat cement for the 5‐h autoclaving period, and 1.35 and 1.57, respectively, for the 6‐h period.
High‐pressure steam curing of high‐slag cement. II. Strength of cement‐sand mixes
Authors: Kamel Abdel‐Aziz H. 
Published: July 2010

AbstractThe strength of dense high‐slag cement‐sand mixes autoclaved at 180 lbf/in2, and of certain aerated mixes autoclaved at pressures ranging from 120 to 210 lbf/in2, has been determined. It was found that maximum strengths were developed in an autoclaving period of 5 h at 180 lbf/in2, and that longer periods, as well as higher autoclaving pressures, yielded lower strengths. The maximum strength values obtained for compacted 1: 3 (w/w) mixes were 425 kg/cm2 in the absence of fine quartz, and 510 kg/cm2 in the presence of suitable addition of fine quartz. The corresponding values for Portland cement mixes were, respectively, 330 and 460 kg/cm2 for a heating period of 5 h, and 360 and 505 kg/cm2 for a period of 6 h.