bluuebunny/crossref_metadata_2025_split huggingface dataset:
The technological importance of the crystallographic and surface properties of copper phthalocyanine pigments
Authors: Fryer John R. , McKay Robert B. , Mather Robert R. , Sing Kenneth S. W. 
Published: July 2010

AbstractNew and previously reported results are combined to emphasise the importance of fundamental crystallographic and surface chemical properties on the technology of copper phthalocyanine pigments. Particular attention is paid to undesirable aggregation of pigment crystals and to the changes in aggregate structure and crystal phase which occur during ageing. The two most commercially significant forms of copper phthalocyanine are the α‐ and β‐polymorphs. The crystals of both consist of parallel molecular stacks. In β‐phase crystals, the coordinate bonding between adjacent molecules within the stacks promotes crystal growth in the direction of the stacks, producing commonly observed rod‐shaped crystals. Moreover, the molecular stacks of the β‐phase, being interlocked, are not readily distorted. In contrast, the distortion of lattice planes in the α‐phase can accommodate mismatch between contiguous crystals, and promote their fusion into strongly coherent aggregates. Although the strength of aggregation is thus influenced by the crystal lattice, the geometric structure of aggregates is largely determined by crystal shape, brick‐shaped crystals being more prone to aggregation than rod‐shaped crystals. Aggregates of brick‐shaped crystals are porous, and solvent molecules can penetrate some way into their internal structure. Ageing may then occur. Changes in crystal phase and aggregate structure are discussed at some length. New evidence is presented for the existence of an intermediate metastable state in the α‐→β‐phase transformation induced by solvents. The β‐→α‐phase change induced by mechanical grinding is shown to start at the surface of β‐phase crystals, and then to extend gradually throughout their bulk. Examples are given of different kinds of ageing of aggregate structures. Ageing of aggregates of α‐phase crystals in liquid toluene involves not only Ostwald ripening and a transformation to the β‐phase, but also crystal fusion (as occurs during ageing in toluene vapour). In liquid n‐propanol, on the other hand, the aggregates are converted to highly consolidated structures.
Nickel extraction by 2‐hydroxy‐5‐tert‐butylbenzaldehyde oxime
Authors: Stepniak‐Biniakiewicz Danuta , Szymanowski Jan 
Published: July 2010

AbstractNickel extraction from aqueous solutions between pH 3 and 10 using 2‐hydroxy‐5‐t‐butylbenzaldehyde oxime was investigated. Iso‐octane, octane, xylene and dichloro‐ethane were used as diluents. It was found that nickel extraction is dependent upon the equilibrium pH, the mol ratio of oxime : nickel and the nature of the diluent. The composition of the nickel‐oxime complex is in the ratio of 1:2. Extraction data, infrared spectra and cryoscopic measurements have shown the association of the oxime in the organic phase and the solvation of the nickel complex by the oxime molecules. The degree of solvation was found to be higher in dichloroethane than in octane.
Adsorption of metal cations on wool carbonising waste. Part 2. Adsorption mechanisms
Authors: Perineau Francis , Farag Karim , Gaset Antoine , Constant Georges 
Published: July 2010

AbstractIn order to elucidate the mechanisms of adsorption of Hg2+, Ag2+, Ni2+, Cr3+, Al3+, Zn2+ and Pb2+ on wool carbonising waste, the possible role of the various ionisable groups (‐SH, ‐SO3H, ‐OSO3H, ‐COOH and ‐NH2) of the substrate has been considered together with the corresponding solubility products and dissociation constants of the metal salts thus formed.
A Survey of Methods for the Preparation of Colloidal Dispersions of Ferric‐hydroxy Polycations
Authors: Segal David L. 
Published: July 2010

AbstractMethods for the preparation of ferric‐hydroxy polycations have been surveyed because of their possible importance in aqueous corrosion processes. The choice of the preparative route is dependent on the desired concentration, purity and volume of the polycation dispersion.
Adsorption of alcohols from aqueous solution by ZSM‐5
Authors: Milestone Neil B. , Bibby David M. 
Published: July 2010

AbstractIsotherms have been measured for the adsorption from aqueous solution of water soluble alcohols onto the zeolite ZSM‐5. For methanol and ethanol the amount of alcohol adsorbed increases with increasing percentage of Al2O3, whereas for n‐butanol the amount adsorbed decreases as the amount of Al2O3 increases. Adsorption of alcohols is also dependent on the cation form. For the alkali metal ion forms, the amount of alcohol adsorbed decreases as the ionic size increases, the effect being particularly pronounced for Cs+. Subsequent alcohol desorption was studied by thermogravimetry and mass spectrometry which showed that the zeolite retained a portion of the alcohol to temperatures (ca 250°C) sufficiently high that catalytic breakdown occurred. This reduces its likely potential for commercial alcohol concentration.
Fundamental aspects of the extraction and stripping of palladium by LIX 65N
Authors: Hoh Ying‐Chu , Chuang Wen‐Shou , Yueh Peng‐Shiung 
Published: July 2010

AbstractThe fundamental aspects of the extraction and stripping of palladium from its chloride solution by LIX 65N diluted with Kermac 470B have been studied. Equilibria of extraction and stripping, temperature effect, the variation of sodium thiosulphate concentration on stripping and rate of extraction and stripping on the system Pd2+‐LIX 65N‐Kermac 470B are reported.The fundamental aspects of the extraction and stripping of palladium from its chloride solution by LIX 65N diluted with Kermac 470B have been studied. Equilibria of extraction and stripping, temperature effect, the variation of sodium thiosulphate concentration on stripping and rate of extraction and stripping on the system Pd2+‐LIX 65N‐Kermac 470B are reported.
Studies on the decomposition of α‐primary hydroperoxide of secondary butyltoluene in alkaline medium
Authors: Kulsrestha Girendra N. , Shanker Uma , Sharma Jaipal S. 
Published: July 2010

Abstractα‐Primary hydroperoxides of s‐butyltoluene (SBT) are preferentially decomposed when the hydroperoxide concentrate is treated with 2 M aqueous sodium hydroxide at 70°C. The decomposition is complete in 1 h. The rate of decomposition and the nature of products formed suggest the reaction to be first order with respect to the primary‐hydroperoxide concentration in accord with the Kornblum‐De La Mare mechanism. Salt formation of the hydroperoxide precedes the decomposition.
Transalkylation of toluene with C9 aromatic hydrocarbons over ZSM5 zeolites
Authors: Meshram Namdeo R. , Kulkarni Suneeta B. , Ratnasamy Paul 
Published: July 2010

AbstractThe transalkylation reactions of a mixture of toluene and C9+ aromatics were studied over HZSM5 catalysts of varying SiO2:Al2O3 ratios (30–800) as well as over a NiHZSM5 catalyst. As the SiO2: Al2O3 ratio is increased, the rate of transalkylation is decreased. Among the C9 aromatics that were present in the feed, the ethyl toluenes were extensively de‐ethylated to toluene. The shape‐selective characteristics of the ZSM5 zeolite were revealed through the relative order of reactivity of the three trimethyl benzene isomers 1.2.4>1.2.3>1.3.5. The stable life of the catalyst can be prolonged by the incorporation of nickel. The influences of process parameters such as temperature, pressure, space velocity and H2: hydrocarbon ratio are also presented. It was observed that the transalkylation of C9 aromatics with toluene to yield xylenes occurs mainly on the external surface of the ZSM5 crystals. The disproportionation of toluene to yield benzene and xylene, however, takes place predominantly in the pore system.
Kinetic studies on the catalytic reduction of o‐, m‐, and p‐nitrophenols by hydrazine
Authors: Goswami N. , Rahman M. L. , Huque M. E. , Qaisuddin M. 
Published: July 2010

AbstractThe kinetics of the reduction of o, m‐ and p‐nitrophenols by hydrazine over Raney nickel catalysts have been studied spectrophotometrically. The reactions have been found to be first order with respect to both hydrazine and nitrocompound. The first order behaviour has been observed at the initial part of each of the reactions. The influences of solvent, salt and the amount of catalyst on the reaction rate have been investigated. The rate constants have been found to depend on the nature of the substrate, the dielectric constant, the ionic strength and the amount of catalyst. The activation energies for the reactions in various solvent compositions have been determined and their variations interpreted in favour of an ionic mechanism. The effect of the p‐substituent on the activation energy has been explained in terms of the electron‐shifting capacity of the substituent.
Some substituted polysaccharides as low temperature middle distillate additives
Authors: Abou Naga H. H. El , Abd Azim W. M. El , Mahmoud M. 
Published: July 2010

AbstractSubstituted polysaccharides with different molecular weights (mol. wt 12 000–15 500) were synthesised by reacting aliphatic acid chlorides with different carbon numbers (C12‐C18) with dextrin. The resulting polymers were purified and tested as pour point depressants and flow improvers for middle distillates (gas oils). Comparative evaluation of these polysaccharides with some commercial additives showed their good activity, especially as flow improvers.
The determination of hydrophilic lipophilic balance values for some hydroxyoximes and their correlation with rates of copper extraction
Authors: Szymanowski Jan , Cox Michael , Hirons Christopher G. 
Published: July 2010

AbstractHydrophilic lipophilic balance (HLB) values provide a measure of the surface activity of organic molecules, and thus may be helpful in the screening of potential metal extractants. Data are presented which correlate the water solubility and rate of copper extraction with the HLB values for a series of hydroxyoximes. The results show a decreasing water solubility and rate of copper extraction as the HLB value decreases, that is, as the reagent becomes more lipophilic. As an estimate of the HLB value can be made from the molecular structure it is possible that some predictions can be made of extraction behaviour.
Comparative kinetic study of ethylbenzene isomerisation on acidic and non‐acidic Pt/Al2O3 catalysts
Authors: Susu Alfred A. , Ako Churchill T. 
Published: July 2010

AbstractEthylbenzene (EB) isomerisation to o‐, m‐ and p‐xylene was investigated in a microcatalytic reactor on acidic and non‐acidic Pt/Al2O3 catalysts. Total conversion and product yield distribution data were determined on both catalysts for EB and the xylenes in the temperature range 513–673 K and 1.8 atm. Total conversion of each of the C8 isomers went through a maximum as the temperature was increased. The onset of reaction occurred at a lower temperature, and the initial rates were higher on the acidic catalyst. Furthermore, the acidic catalyst was found to be very selective in the production of p‐xylene at temperatures less than 563 K, and of p‐ and o‐xylene at temperatures less between 563 and 593 K. The Wei‐Prater method was used for the calculation of absolute rate constants for EB isomerisation on both catalysts. Generally, the rate constants were higher on acidic Pt/Al2O3.
Removal of Cr(V1) from aqueous solutions by adsorption on fly ash‐wollastonite
Authors: Panday K. K. , Prasad Gur , Singh V. N. 
Published: July 2010

AbstractThe ability of a homogeneous mixture of fly ash and wollastonite (1:1) to remove Cr(V1) from aqueous solutions by adsorption has been investigated. The extent of removal is dependent on concentration, pH and temperature of the solution. The applicability of the Langmuir isotherm for the present system has been tested and the surface mass transfer coefficient at 30°C and pH 2.0 determined. Maximum removal was observed at pH 2.0 and 30°C. The adsorption is first governed by diffusion followed by surface compound formation. The thermodynamic parameters, desorption results and infrared studies indicated that the surface compounds, formed by interaction of adsorbate ions and different constituents of mixed adsorbent, were stable in nature.
Oxidation of cyclohexanone to adipic acid with a cobalt acetate/oxygen/acetic acid system
Authors: Rae Dubasi Govardhana , Raghunathan T. S. 
Published: July 2010

AbstractThe liquid phase oxidation of cyclohexanone to adipic acid at 378 K using oxygen as the oxidising agent and cobalt acetate as the catalyst in an acetic acid medium was investigated both at atmospheric pressure and at a pressure of 0.5MN m−2. The effects of catalyst concentration, solvent concentration and partial pressure of oxygen, were studied at a constant stirrer speed of 535 rev min−1. Increasing the solvent concentration and decreasing the catalyst concentration (up to 0.113×10−3 kmol m−3) had positive effects on the overall first order reaction rate constant. It was also found to vary linearly with gas flow rate.
Effects of precipitation temperature on the powder properties of Mg(OH)2 and calcined MgO
Authors: Copperthwaite M. , Brett N. H. 
Published: July 2010

AbstractMg(OH)2 has been precipitated from MgCl2 solution with CaO at temperatures in the range 0–55°C and with a final pH of 11.7. The hydroxides, and the oxides derived from them by calcination under standard conditions, have been characterised by settling rate, chemical analysis, tap density, X‐ray crystallite size, B.E.T. surface area, electron microscopy and green and fired density of isostatically pressed pellets. Increasing the precipitation temperature affects these parameters in different ways and attempts have been made to correlate these changes.
Determination of the heat change in solvent extraction of metals. The extraction of zinc (II) from hydrochloric acid solutions by high molecular weight amines in various organic solvents
Authors: Sato Taichi , Nakamura Takato , Kuwahara Masami 
Published: July 2010

AbstractThe heat change associated with the uptake of zinc (II) has been examined by using a twin type isoperibol calorimeter in the extraction of zinc (II) from hydrochloric acid solutions by trioctylamine hydrochloride (TOAHCl) and trioctylmethyl‐ammonium chloride (TOMAC) in various organic solvents such as benzene, chlorobenzene, o‐dichlorobenzene, toluene, m‐xylene, nitrobenzene, carbon tetrachloride and 1, 2‐dichloroethane. It was found that the dependence of apparent molar heat change (the value of the heat change detected with regard to the concentration of zinc (II) reacted) on the aqueous chloride concentration could be attributed to the change in the distribution of zinc (II) chloride species in the aqueous phase. Taking account of this fact, variable Y, which constitutes the sum of the change in enthalpies for the relevant steps in the extraction of zinc (II), except the transformation of ZnClj(2‐j)+ to ZnCl42‐, in the aqueous phase, is introduced. From the values of Y obtained, it is concluded that in the extraction by TOMAC, Y correlates with the solubility parameter of diluent, suggesting that the organic phases may be regarded as regular solutions, while in the extraction by TOAHCl, no clear‐cut relation holds between Y and the physico‐chemical constants of the diluent such as dipole moment, dielectric constant and solubility parameters.
Equilibrium studies on adsorption of basic dyes on hardwood
Authors: Asfour H. M. , Fadali O. A. , Nassar M. M. , El‐Geundi M. S. 
Published: July 2010

AbstractEquilibrium conditions of adsorption of a basic dye on hardwood sawdust were studied using the Langmuir and Freundlich isotherms. Two sets of experiments were carried out at different particle sizes and temperatures. The adsorption of the basic dye on hardwood was found to conform with the two isotherms. The capacity of hardwood for the adsorption of basic dye was found to increase by decreasing the particle size and increasing the temperature. The cost of hardwood adsorbent is only 8.4% that of activated carbon.
Colour removal from textile effluents using hardwood sawdust as an absorbent
Authors: Asfour H. M. , Nassar M. M. , Fadali O. A. , El‐Geundi M. S. 
Published: July 2010

AbstractDecolourisation of a dilute solution of a basic dyestuff was carried out by using hardwood sawdust as adsorbent. At 80°C 85% decolourisation occurred within 100 min at an initial concentration (Co) of 200 mg dm−3. There was a 44% reduction in contact time when the temperature was raised from 25 to 80°C. The rate parameter for different initial dye concentrations was found to follow the equation: kco=4.20Co0.88 and the rate parameter for different mean diameter dm followed the equation kdm=4.1 (l/dm)0.135. The activation energy of the process was 9.83 kJ mol−1 which shows that the rate controlling step is intraparticle diffusion.
Factors affecting the solubility of gypsum: II. Effect of sodium hydroxide under various conditions
Authors: Ghorab Hanaa Y. , Fetouh Safaa H. Abou El 
Published: July 2010

AbstractA quantitative estimation of the effect of sodium hydroxide on the solubility of gypsum in the presence of lime at 30, 60 and 100°C is given. At 30°C the solubility of gypsum was promoted by a 0.0146M solution of sodium hydroxide which at a concentration as low as 0.0029M raised the sulphate ion concentration at 60 and 100°C. At the three temperatures studied the solubility curves of gypsum first rose slowly then more rapidly around 0.02 to 0.08M NaOH. In the range 0.08 to 1M NaOH solution, a constant value of the sulphate ion concentration was measured which corresponded to the complete dissolution of gypsum, even in the presence of lime. The solubility curve of gypsum was lowered slightly at 30°C in a supersaturated lime solution and was depressed by concentrations lower than or equal to 0.02M NaOH solutions at 60 and 100°C.
Recommended flowsheets for the electrolytic extraction of lead and zinc from red sea polymetal ore
Authors: Madkour Loutfy H. 
Published: July 2010

AbstractThe polymetal complex ore Umm‐Gheig considered in Egypt as a rather rich source of lead and zinc is subjected to mineralogical, chemical, spectral, X‐ray and differential thermal analyses. Hydrometallurgical treatments based on leaching, precipitation and electrodeposition of metal from the ore are established. The influences of current density, temperature and metal ion concentration on the Faradic current efficiency are discussed. Advantages and disadvantages of flowsheets and various approaches depending on convenient baths for the electro‐deposition of metals are investigated. The results of electron microscopic investigation confirmed by metal value data given in the A.S.T.M. cards coincide well with those given by chemical analysis.
Organic matter and sulphur distribution in phosphorites: Relevance to phosphate processing
Authors: Mair A. Donald 
Published: July 2010

AbstractOrganic matter from North Carolina and Idaho phosphorites has been extracted and characterised using humic acid, kerogen and bitumen fractions. Extracts from thermally treated rock showed that the organic matter from the two source rocks responds quite differently to the heat treatment. With current commercial calcination of both North Carolina and Idaho phosphate rock at about 800°C, problems with acid‐evolvable sulphide formation have arisen. From the findings made on the thermal behaviour of the organic matter and the associated sulphur redistribution, alternative processing strategies have been suggested for both North Carolina and Idaho phosphorites. Since these two rocks represent extremes in maturity for the contained organic matter, the results should be of relevance to other organic‐rich unweathered and low‐grade phosphorite or phosphatic shale deposits.
Cation exchange in clays and mudrocks by methylene blue
Authors: Taylor Roy K. 
Published: July 2010

AbstractThe nature of methylene blue (hydrochloride) adsorption is reviewed because the dye has recently been adopted for determining the presence of clay in quarry aggregates. Although it is demonstrated that methylene blue is not an ideal exchange reagent, details are given for overcoming most of the shortcomings, with particular reference to the aggregates test. It is demonstrated that methylene blue commonly underestimates the cation exchange capacity (CEC) of untreated expandable smectites. In contrast, it provides a fair reflection of the change in ratio of 7 Å/10 Å clay minerals in British mudrocks and overconsolidated clays. Plasticity indices of the latter show a high level of positive correlation with measured CEC.
Selective transformation of benzyl chloride into benzyl thiocyanate in the presence of ion‐exchange resins. Generalisation of the reaction
Authors: Catusse Chantal , Catusse Robert , Gharbi Rachid El , Gaset Antoine 
Published: July 2010

AbstractThe use of ion‐exchange resins as a support for thiocyanate ions made it possible to transform benzylic or aliphatic halides into thiocyanates both in high yield and with remarkable selectivity. A study of the effects of various physicochemical parameters governing the behaviour of the ion exchanger allowed the most favourable reaction conditions to be determined. The best transformation rates were obtained using a macroporous resin, appropriately hydrated, in a non water‐miscible solvent.
Dyestuffs for synthetic polymer fibres: 4‐N‐morpholinoazobenzenes
Authors: Peters Arnold T. , Cheung Sing Kwen 
Published: July 2010

AbstractA series of monoazo disperse dyes derived from the coupling to N‐phenylmorpholine of diazotised anilines and aminothiazole derivatives is described. The colour, dyeing and fastness properties of the dyes is compared to those of the analogous dyes based on N‐ethyl‐N‐β‐hydroxy‐ethylaniline. Dyes from the ring closed heterocyclic coupling components dye synthetic‐polymer fibres in deep colours of good fastness properties and show significant hypsochromic colour shifts compared to the uncyclised derivatives.
Electrodeposition of cobalt‐nickel alloys from ammoniacal single‐complex baths
Authors: El‐Rehim Sayed S. Abd , El‐Halim Abd‐Halim M. Abd , Osman Magda M. 
Published: July 2010

AbstractThe electrodeposition of cobalt‐nickel alloys has been studied from ammoniacal single‐complex baths containing 5–50 CoSo4·7H2O, 5–50 NiCl2·46H2O, 20–50 g dm−3 (NH4)2SO4 and 250–350 cm3 dm−3 NH4OH (20.5% solution). The effects of the plating current density and the concentrations of the bath constituents on the cathodic polarisation, current efficiency and composition of the alloy were investigated. A wide range of alloy compositions with a current efficiency of 60–80% could be obtained from the main baths examined. The alloy plating system interchanged between the normal and the anomalous types depending upon the plating current density and the concentration of NH+4 ion in the bath. Electron microscopic and X‐ray diffraction studies proved that the structure of the electrodeposited alloy was controlled by the alloy composition.