bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of ultrafine iron fluoride by use of the flame‐reactor technology
Authors: Mange Michel , Chatelut Francis , Eyraud Charles
Published: July 2010

Highly dispersed iron fluoride samples were prepared by the very fast reaction between gaseous fluorine and iron pentacarbonyl in a flame reactor. The surface area of the sample depended principally on the reactant proportions and on the dilution of the reaction zone with an inert gas.
Lightfastness, phototendering and fluorescence of 3‐methoxybenzanthrone
Authors: Allen N. S. , McKellar J. F. , Protopapas S.
Published: July 2010

Studies have been made of the fluorescence quantum yields and lifetimes, the photostability and the phototendering behaviour of 3‐methoxybenzanthrone in nylon 6,6 and in polyester to determine the nature of the primary process responsible for nylon phototendering. The results indicate that in a polar environment such as nylon 6,6 there is an increased probability of dye‐substrate interaction. The results of a study of the fluorescence quenching by amines of varying ionisation potential indicates that the primary process responsible for nylon phototendering may be one of electron abstraction from the substrate.
Thermolysis of mono‐, di‐ and tri‐benzylamines, IV
Authors: Badr M. Zarif A. , Aly Morsy M. , El‐Sherief Hassan A. H. , Rahaman Abdo E. Abdel
Published: July 2010

Thermolysis of mono‐, di‐ or tri‐benzylamine for some days in the absence of promoters gave the same products: ammonia, toluene, dibenzyl, stilbene and benzaldehyde. Thermolysis of dibenzylamine in isoquinoline as a solvent gave 1‐benzyl‐isoquinoline together with the normal pyrolysis products. When naphthalene and 2‐naphthol are used as solvents, benzylation of the solvent nuclei was observed to give 1‐ and 2‐benzylnaphthalenes and 1‐benzyl‐2‐naphthol respectively. In conclusion, thermolysis of tri‐, di‐ or mono‐benzylamines proceeds through a free radical mechanism with successive conversions of the tertiary, through secondary to primary alkylamines resulting in the same pyrolysis products.
The chemistry of ethyl silicate binders in refractory technology
Authors: Biddle Keith D. , Das Anup K. , Jones Kenneth , Emblem Harold G.
Published: July 2010

The chemistry of the processes involved when an alkyl silicate such as ethyl silicate acts as a binder in refractory technology is described. The gel forming process involving catalysed hydrolysis and condensation of ethyl silicate and tetra‐alkyl silicates has been studied using amine catalysts. Thermal studies of gels obtained from technical ethyl silicate and of gels obtained from technical ethyl silicate incorporated in refractory materials, together with infrared spectroscopy studies of gels obtained from technical ethyl silicate, suggest the nature of the degradation products, and the weight‐loss patterns observed support the proposed mechanisms.
The potentiometric titration of gum karaya aud some other tree‐exudate gums
Authors: Jefferies Martin , Pass Geoffrey , Phillips Glyn O.
Published: July 2010

Potentiometric titration of gum karaya was used to determine the acid equivalent weight and the proportions of the acid groups in the salt form and the free acid form. Alkaline hydrolysis was used to determine the acyl groups attached to the gum. These determinations were also carried out with other tree‐exudate gums including gum arabic, gum jeol (Lannea coromandelica gum) and tree‐gums from Sterculia tragacantha, Acacia sieberana, Acacia polyacantha and Albizia zygia. Potentiometric titration also showed the presence of basic groups attached to the polyanion in some gums. The variation of viscosity with pH can be correlated with the potentiometric titration curve.
Photosynthetic production of biomass and starch by Chlorella in chemostat culture
Authors: Pirt Margaret Watts , Pirt S. John
Published: July 2010

A high temperature strain of Chlorella was grown photosynthetically with nitrogen limitation of growth over a range of dilution rates up to the critical value of 0.22 h−1. The “total cell dry weight” is distinguished from the “real biomass” which is total cell dry weight less starch. Nitrogen‐limited growth of Chlorella, in terms of real biomass, obeyed the simple Monod model of chemostat culture. In a low EDTA medium (about 1 mol of EDTA per mol Fe3+) ferric hydroxide precipitated at pH 7 and caused iron‐limited growth to occur at high dilution rates. Iron precipitation and consequently iron‐limited growth, were prevented by increasing the EDTA to 2 mol per mol Fe3+. It was deduced that Fe3+ was available to the cells only as Fe‐EDTA complex, not as free Fe3+ in the medium. A glycogen‐like starch was stored in the cells and the starch content approached 50% of the total dry weight of cells at low dilution rates. The starch content of the total cell dry weight was practically independent of the growth temperature over the range 28–40°C and the pH over the range 5.5–8.5. The specific rate of starch production (qstarch) reached 0.05 g of starch/g real biomass h.
Isolation of hydrophilic fermentation products by adsorption chromatography
Authors: Voser Walter
Published: July 2010

The isolation of hydrophilic fermentation products by adsorption chromatography with synthetic macroporous polystyrene‐type resins is discussed. Particular attention is given to the problems of scale‐up and the use of these resins for industrial production.
Influence of high partial pressure of carbon dioxide and/or oxygen on nitrification
Authors: Jones Gordon L. , Paskins Andrew R.
Published: July 2010

The advent of new intensive wastewater treatment processes with high rates of solution of oxygen, such as the oxygen activated‐sludge process and the Deep‐Shaft process, implies that there will be conditions of high concentrations of carbon dioxide and oxygen in the mixed liquor. These processes, as operated, have problems in maintaining nitrification. To determine how the above conditions affect the nitrifying bacteria, other than by reducing the pH, a mixed culture of nitrifying bacteria was maintained on a synthetic substrate in a computer‐controlled chemostat at constant pH and temperature, with different proportions of carbon dioxide and oxygen in the aeration gas. The specific growth rate of the ammonia‐oxidising bacteria was independent of the concentration of carbon dioxide in the gaseous phase when this was between 0.03 and 2.0%. The ammonia‐oxidising bacteria were initially inhibited by high partial pressures of oxygen but eventually became acclimatised and retained this property, even when grown for several generations at lower partial pressures.
Substrate utilisation by plant‐cell cultures
Authors: Fowler Michael W.
Published: July 2010

Plant cell cultures have been grown on a wide range of carbon sources in addition to the traditional ones of sucrose and glucose. Biomass yields and growth rates vary greatly between the different carbon sources and there is a variation in response between different cell cultures to individual carbon sources. Some attempts have been made to grow cell cultures on ‘waste’ and related carbon sources, such as lactose, maltose, starch, molasses and milk whey. Only maltose was found to support growth to anything near the levels observed with glucose and sucrose. In the case of molasses carbon source cell growth was either non‐existent or only just measurable. All the data point to glucose as being the most suitable carbon source, principally on the grounds of biomass yield and growth rate. It should be noted, however, that other carbon sources do appear to have a major (positive) influence on natural product synthesis. Uptake into the cell is an important aspect of carbohydrate utilisation. There is strong evidence that from disaccharides upwards, major degradation to smaller units occurs before uptake. In some cases the necessary enzymes appear to be excreted into the culture broth, in others they may be located within the cell wall; invertase that hydrolyses sucrose is a good example. Once the products of carbohydrate degradation and mobilisation enter the cell they may suffer one of two fates, oxidation or utilisation for biosynthesis. The precise split between these two varies depending on such factors as cell growth rate, cell size, nutrient broth composition and carbohydrate status of the cells. In general rapidly growing cells have a high rate of oxidation, whereas cells growing more slowly tend to be more directed towards biosynthesis. Carbohydrate utilisation is a key area of study, underpinning as it does both biomass yield and natural product synthesis.
TAN: A new molluscicide and algicide from the fruits of Acacia nilotica
Authors: Ayoub Saad Mohamed Hussein
Published: July 2010

TAN, a new molluscicide and algicide from the fruits of Acacia nilotica subsp. nilotica was produced on a pilot scale by spray‐drying. Being a natural product, TAN could, after treatment, become also an economic concentrated raw material in the tanning and pharmaceutical industries, and in the manufacture of dyes and inks.
Adsorption of dyestuffs from aqueous solutions with activated carbon II: Column studies and simplified design models
Authors: McKay Gordon
Published: July 2010

The design of batch contact and fixed‐bed adsorption systems has been discussed. A simplified design model (the Bed‐Depth Service Time model) has been proposed and tested. The effects of bed depth, dye flow rate and carbon particle size, for the adsorption of Telon Blue and Deorlene Yellow, have been correlated with this design procedure.
Adsorption of copper (II) ions from aqueous solution by five silica samples
Authors: Bye Gerald C. , McEvoy Michael , Malati Mounir A.
Published: July 2010

Samples of BDH precipitated silica, Degussa TK900 (non‐porous) and Crosfield xerogels [A (mesoporous), B (mesoporous) and C (microporous)] were characterised by chemical analysis, by Coulter particle‐size analysis, by electron microscopy and by their BET surface area. The point of zero charge, determined by potentiometric acid/alkali titration, was at pH 2.8–2.9 for all samples. The surface charge density for the non‐porous sample was lower than that for the porous samples. The results of the initial rate of exchange of the silicas with tritiated water suggested an exchange with the physically held water, which is lost at 393 K. The adsorption isotherms of Cu (II), determined by atomic absorption spectrophotometry at pH 6 and 323 K, followed the Langmuir equation. The limiting adsorption capacity decreased in the order: precipitated silica > B > A > C > TK900. This order could not be correlated with the BET nitrogen surface area or the pore volumes of the samples. However, the order was the same as the Na+ content of the silicas. Desorption runs established that adsorption was not reversible, in fact desorption was significant at equilibrium concentrations approaching zero. An apparent endothermic heat of adsorption of Cu (II) on precipitated silica, calculated from the data of the Langmuir isotherms at different temperatures, was 23 kJ mol−1. The increase in the adsorption of Cu (II) as the pH increased may be ascribed to the adsorption of hydrolysed species. From the Grahame equation, the estimated free energy of specific adsorption of Cu (II) on precipitated silica near the point of zero charge was‐13 kJ mol−1.
Bacillus sphaericus V‐penicillin acylase. II. Isolation and characterisation
Authors: Carlsen Flemming , Emborg Claus
Published: July 2010

Bacillus sphaericus (strain NCTC 10338) produces an intracellular V‐penicillin acylase which has been isolated and partially purified after lysozyme treatment. The acylase hydrolyses V‐penicillin and V‐cephalosporin but not G‐penicillin and ampicillin. Optimal activity occurred at 40–60°C and pH 6.8. The system showed some characteristics of an SH‐enzyme and was inhibited by phenoxyacetic acid (non‐competitive, Ki =30 mM) and 6‐aminopenicillanic acid (competitive, Ki =9 mM). The Km for V‐penicillin was 140 mM.
Conversion of heavy oils into more desirable feedstocks
Authors: Laine J. , Trimm David L.
Published: July 2010

With the realisation that the supply of crude oil is limited, the processing and conversion of heavy oils, considered less desirable in the past, into transport and fuels or useful chemicals, is reviewed.
Some studies of silica‐supported Pd‐Au catalysts and their behaviour in the hydrogenation of 1‐octyne in the liquid phase
Authors: Brown J. M. , Caga I. T. , Welsh C. K. , Wilson S. J. , Winterbottom J. M.
Published: July 2010

A number of silica‐supported palladium‐gold (Pd‐Au) catalysts have been prepared by simultaneous impregnation covering the range 0–84 atomic % gold in palladium, the total metal loading on the silica being about 2% (w/w). In addition, a smaller number of unsupported Pd‐Au catalysts covering the same composition range was prepared by Adams oxide methods and these are compared with the supported catalysts. The catalysts were examined, as appropriate, by temperature‐programmed reduction (TPR), carbon monoxide chemisorption for metal surface area measurement, X‐ray diffraction and Auger electron spectroscopy. The hydrogen‐reduced catalysts were used for 1‐octyne hydrogenation in the range 30–70°C, at 1 atm. total pressure, with propan‐1‐ol as reaction solvent. Certain catalysts were also air‐treated after reduction, after which their activities and surface areas were determined. For the supported Pd‐Au alloys, TPR and catalyst‐activity studies indicated that alloying between gold and palladium occurred, possibly over the whole composition range, but more certainly up to 50–60 atomic % gold in palladium. No evidence for alloying was found in the case of the unsupported Adam Pd‐Au catalysts on the basis of X‐ray, Auger spectroscopic and activity measurements. Air‐treatment of selected supported catalysts resulted in enhanced activity for 1‐octene hydrogenation and increased metal surface areas. This is attributed to removal of surface carbon and an activity maximum was observed for an air/catalyst ratio of 0.2–0.3 cm3of air/mg of catalyst. Beyond the optimum air/catalyst ratio, activity and surface area decreased again, probably due to oxygen or water chemisorption on palladium. 1‐Octyne hydrogenation rate was unaffected by such treatment and its ability to chemisorb strongly causes inhibition of activity, whether or not carbon is present.
Ion‐exchange behaviour of hydrous zirconia in mixed solvents: Thermodynamics of anion exchange in methanolic solutions
Authors: Misak N. Z. , Ghoneimy H. F.
Published: July 2010

Addition of 30 and 60% (w/w) methanol decreases ΔG0 and increases ΔH0 and ΔS0 of the exchange of Cl− for NO3− in hydrous zirconia and thus the increase of selectivity constant is due to the entropy term. In the case of exchange of Br− for NO3−, a decrease of the selectivity constant occurs at 30% (w/w) methanol also due to the entropy changes, whereas at 60% (w/w) methanol, the selectivity constant continues to decrease as a result of both ΔHo and ΔSo terms which became higher than in the aqueous solution. Selectivity reversal occurs in the NO3−/Cl− exchange at 60% (w/w) methanol, whereas in the NO3−/Br− exchange, it occurs already at 30% (w/w) methanol. Calculations for Cl−/Br− exchange with the use of transfer thermo‐dynamic data revealed that ion‐solvent interactions in the liquid phase are the sole factor governing the variation of ΔG0 on addition of methanol, and thus ΔG0 (or selectivity constant) in the mixed media could be largely calculated from the value in the aqueous medium when these interactions are accounted for by introducing transfer free energy (or medium effect) terms. However, changes in the solid‐phase interactions, leading to decreases in ΔH0 and ΔS0, do occur on addition of methanol but these decreases largely cancel each other.
High pressure synthesis of diphenylamine from aniline and phenol
Authors: Radhakrishnan Mala , Das Birendra N. , Nandi Dilip K.
Published: July 2010

The synthesis of diphenylamine from aniline and phenol has been carried out in the presence of a phosphoric acid catalyst. Very high pressure has no beneficial effect on the synthesis of diphenylamine. Under optimum conditions (558 K 0.552 × 106 N m−2; residence period 2 h; aniline to phenol mol ratio, 1:3 and aniline to catalyst mol ratio, 1:0.3232), the conversion of aniline to diphenylamine was 72.57%.
Separation of some radio‐elements from low‐level liquid wastes using hemimorphite mineral
Authors: Hafez Mohamed B. , Abdel‐Rassoul A. A.
Published: July 2010

The use of hemimorphite mineral for possible decontamination of low‐level radioactive liquid wastes has been investigated. Fixation and subsequent elution systems for some radionuclides from both aqueous and phosphate media using hemimorphite were studied. Changes in pH and ageing of radioactive tracers in used media were the principal factors affecting such systems. Sorption rather than ion‐exchange is likely to occur.
Optimised aerobic and thermophilic treatment of municipal sewage sludges and night soils in a continuous operation
Authors: H. Carlson Carl‐Göran
Published: July 2010

In this investigation aerobic and thermophilic (57°C) biodegradation of raw and partly digested municipal sludges and night soils is optimised at a commercial waste treatment centre. The feed is monitored to 5–7% dry solids and BOD7 concentration of 30–50 g kg−1. BOD7 removal exceeds 85%. Effluents are accepted for land infiltration.
The role of pigmentation in the growth and survival of the methanol‐utilising bacterium, Pseudomonas extorquern
Authors: Merabtine Hamida , Scott Christopher D. B. , Harrison David E. F. , Oliver Stephen G.
Published: July 2010

The role of pigmentation in the growth and survival of Pseudomonas extorquens (NCIB 9399) has been examined in both the pink wild‐type strain and a yellow mutant (T358) derived from it. The effect of inhibitors of carotenoid biosynthesis has also been assessed. The yellow mutant was found to compete out the wild‐type when the two organisms were grown together in methanol‐limited continuous culture. The methanol dehydrogenase of the mutant was found to have a lower Km and higher Vmax than that of the wild‐type. The response of mutant and wild‐type cells to the growth inhibitory effects of methanol was similar. Moreover, incubation with chemical inhibitors of carotenoid biosynthesis did not alter the growth rate of the wild‐type over a range of methanol concentrations. The pink pigment did, however, have a photoprotective effect and stationary phase wild‐type cells were more resistant to the killing effects of ultraviolet light than the yellow mutant cells.
Adsorption from aqueous solution by δ‐manganese dioxide I. Adsorption of the alkaline‐earth cations
Authors: Gray Malcolm J. , Malati Mounir A.
Published: July 2010

The adsorption isotherms of M2+ ions (M = Mg, Ca, Sr or Ba) were determined at pH 7.0 and at different temperatures. The adsorbent, δ‐MnO2, was converted to the K+ form prior to adsorption and about 1.5 mol K+ ions were released per mol of M2+ ions adsorbed. The adsorption capacity at a given temperature increased in the series: Mg2+ < Ca2+ ≦ Sr2+ < Ba2+. This was explained by an ion exchange mechanism between hydrated ions: K+ ions in the outer Helmholtz layer and M2+ ions in the bulk of the solution. The radii of the hydrated ions decreased in the series: Mg2+ > Ca2+ > Sr2+ > Ba2+. The adsorption of M2+ ions at pH values below the point of zero charge (pH 3.3) was significant for Mg2+ ions only. Although adsorption was not strictly reversible, the results fitted the Langmuir isotherm and ‘apparent heats of adsorption’, Q, were calculated. The endothermic heats (Q = 20,18, 11 and 5 kJ mol−1 for Mg2+, Ca2+, Sr2+ and Ba2+ adsorption respectively) indicated positive entropy contributions which are expected for the adsorption mechanism suggested. The decrease in Q down the alkaline‐earth group was correlated to the entropy effects and to the hydration numbers of the cations.
Electroreduction of phenyl cyanide and benzyl cyanide on nickel cathode
Authors: Krishnan Venkatasubramanian , Muthukumaran Arunachalam , Ragupathy Kanagasabhapathy , Udupa Venkata Krishna
Published: July 2010

An electrochemical method for preparation of primary amines from organic cyanides using nickel black deposited over graphite substrate as cathode has been studied. It has been observed that it is possible to reduce benzyl cyanide both in ethanolic sulphuric acid and in aqueous ethanolic ammonium sulphate media. But with phenyl cyanide, the reduction is efficient only in ethanolic sulphuric acid medium. Both in laboratory and 75 A scale experiments 62–66% yield has been obtained at a current efficiency of 36–44% for benzylamine. Similarly a yield ranging from 60–80% with a current efficiency of 36–52% has been obtained for β‐phenylethylamine both in laboratory scale and also in large scale experiments. Results of operation of a 500 A cell for the preparation of β‐phenylethylamine are also presented.
Solvent extraction in scrap and waste processing
Authors: Flett Douglas S.
Published: July 2010

The role of solvent extraction in the processing of metalliferous scrap and waste is reviewed. Its use is found to be significant and it is likely to play an increasingly important role in the development of scrap and waste reprocessing flowsheets.
Continuous ion exchange with magnetic shell resins dealkalisation part V—Process development
Authors: Priestley Anthony J.
Published: July 2010

A search has been made for a continuous ion exchange adsorber design that would be suitable for flow rates in the range 4500–45 000 m3day−1. By the use of fundamental kinetic data, various types of adsorber were designed from first principles. Economic analysis of the results of this design study suggested the use of a simple pipeline, in which the ion exchange resin is carried along in the turbulent water flow. Experimental work confirmed the predicted advantages of the pipeline as an adsorption vessel.
Growth yield of Rhodopseudomonas spheroides in light‐anaerobic and dark‐aerobic cultures
Authors: Aiba Shuichi , Koizumi Jun‐Ichi , Nishizawa Yoshinori
Published: July 2010

An experimental fact that the quantum yield, defined by moles of thiocyanate ion released per unit light energy absorbed in a photochemical reaction of Reinecke's salt solution, remains almost unchanged in a visible wavelength range from 400 to 700 nm was applied to the measurement of light energy absorbed by Rhodopseudomonas spheroides in a continuous culture vessel in situ. This technique of light energy assessment was deemed to be significant in the sense that not only the light energy that was transmitted but also that that was scattered in three dimensions could be assessed. Values of growth yield, Ykj, for light‐anaerobic and dark‐aerobic cultivations of this microorganism were 0.012 g cell per kJ and 0.028 g cell per kJ, respectively. These values sound reasonable in the light of relevant data on Ykj published by other workers on various chemo‐organotrophic and/or photolithotrophic microbes.
Bismuth molybdates: Preparation and catalysis
Authors: Batist Philip A.
Published: July 2010

Only one bismuth molybdate, Bi2MoO6 or the Koechlinite phase, has proved to be an active catalyst for olefin oxidation. The activities of the other compounds, Bi2Mo2O9 and Bi2Mo3O12 are merely due to coverage of these compounds by Bi2MoO6. This coverage is also due to the fact that the Koechlinite phase is quickly obtained from the reactants, whereas the other compounds are obtained more slowly. Koechlinite is active and stable, but sensitive to decomposition if not treated properly. A procedure is described for obtaining pure and active Koechlinite crystals. Such a procedure is important, because the natural mineral Koechlinite is always contaminated with quartz. Surface models are given to explain the selectivity, the non‐selective reaction, oxygen diffusion and deactivation of differently prepared bismuth molybdate catalysts.
Molecular statistical study of thermodynamic characteristics of hydrocarbon adsorption on zeolites
Authors: Kiselev A. V.
Published: July 2010

The adsorption of hydrocarbons on zeolites, a process of major industrial significance, is considered in detail.
Reclamation of waste plastics and rubber: Recovery of materials and energy
Authors: Poller Robert C.
Published: July 2010

The world‐wide production of waste plastics and rubber is increasing with much of it appearing in domestic refuse. This waste should be regarded as a minor but valuable resource of energy and materials but it is largely dumped instead of being reclaimed. Those methods of reclamation which lead to breakdown of the polymeric structure are considered here. The principal methods of recycling are combustion with energy recovery, pyrolysis and depolymerisation. Each of these methods is surveyed in detail. It is concluded that social and economic measures are needed to stimulate greater use of existing technology which, in turn, would allow the development of more sophisticated technology.
The effect of preparation variables on the dispersion of supported platinum catalysts
Authors: Palmer M. B. , Vannice M. A.
Published: July 2010

The effects of several preparation variables on the dispersion of supported platinum catalysts were examined in this study. Supported catalysts were prepared using two different platinum salts, four high surface area support materials, and two aqueous deposition techniques. The catalysts were characterised by hydrogen chemisorption, oxygen chemisorption, and the hydrogen titration reaction. In addition, X‐ray diffraction measurements were conducted on all catalysts. Results from this study show that one of the platinum salts, chloroplatinic acid, always gave an equally or more highly dispersed catalyst than the other salt, tetraammine platinum (II) nitrate. The incipient wetness preparation technique produced equal or better dispersions than did the excess water method, with the possible exception of the silica‐alumina support. The highest dispersions were attained with alumina, and the lowest with carbon. In some samples, a lack of good agreement existed between X‐ray diffraction and chemisorption measurements of crystallite size which indicated broad or bimodal particle size distributions. However, these X‐ray data were qualitatively helpful in understanding the unusual chemisorption behaviour of Pt/C catalysts, one of which had a dispersion higher than any previous reported Pt/C catalyst prepared by aqueous impregnation techniques. Experiments were also conducted which showed that either a 1 h or a 12 h treatment in hydrogen at 723 K was sufficient to reduce the platinum salt, and 1 h or 12 h evacuations at 698 K gave similar results. Finally, it was found that approximately one‐half of the hydrogen monolayer on supported Pt could be removed by evacuating for 1 h at 300 K.
Kinetics of citric acid fermentation from n‐paraffins by yeasts
Authors: Moresi Mauro , Cimarelli Delfo , Gasparrini Giuliana , Liuzzo Giuseppe , Marinelli Roberto
Published: July 2010

In this work, yeast of the genus Candida was screened by means of shaken‐flask and jar fermentations. Two strains, Candida lipolytica Cooper and ATCC 8661, were selected. Their citric acid productivity was 0.79 and 0.67 g g−1 of n‐paraffins consumed, respectively, and their citric: total citric and isocitric acid ratios ranged from 0.82 to 0.93, respectively. The experimental results (cell growth and total citric and isocitric acid formation) were described by using an unstructured kinetic model which has been proposed previously (standard error was less than 10%). Moreover, each independent kinetic parameter was correlated with the aeration rate of the culture medium by means of empirical regressions. Aeration of the culture medium showed a large influence on the product yield. For instance, the strain C. lipolytica Cooper exhibited the highest productivity among the examined strains, associated with the largest air consumption.
The application of the principles of reaction engineering to electrochemical cell design
Authors: Fleischmann Martin , Jansson Robert E. W.
Published: July 2010

It is shown that detailed descriptions of complex electrochemical reactors may be obtained by using electrochemical analogues of the dye marker technique. Most cells show some degree of segregation and the extent of the stagnant phase as well as the residence time distribution, degree of dispersion etc. can be correlated with the hydrodynamic conditions. The performance of electrochemical reactors is shown to be strongly dependent on the contacting patterns. It is therefore important to develop methods for predicting the distribution of reaction in space in order to predict the overall performance. It is shown that approximate design methods can be applied which combine information on the local reaction rates with information on the distribution of potential; this method of modelling is compared to that used for non‐isothermal endothermic reactions in conventional reactors.
Evaluation of activity, selectivity and stability of catalysts for naphtha reforming
Authors: Sad Mario R. , Fígoli Nora S. , Beltramini Jorge N. , Jablonski Estanislao L. , Lazzaroni Ricardo A. , Parera José M.
Published: July 2010

A method to evaluate naphtha‐reforming catalysts has been developed and the equipment and its operation is described here in detail. The octane number computed by chromatographic analysis is similar to the one derived using the motor method and is proportional to the total aromatic concentration. The aromatic concentration is a quick and easy method to evaluate catalyst activity. The liquid yield and selectivity were also measured chromatographically. The efficiencies of commercial and prepared catalysts were compared by plotting octane number vs liquid yield. The catalysts were Pt/Al3O3‐Cl and the process variables were similar to those used in industry. The feed was n‐heptane or C6‐C8 naphtha. Accelerated deactivation tests at lower pressure and hydrogen : hydrocarbon ratios were performed to study stability in shorter times.
The inhibition of the cathodic reduction of hypochlorite by films deposited at the cathode surface
Authors: Kuhn Anselm T. , Hamzah Harun , Collins Gilbert C. S.
Published: July 2010

Films, either organic or inorganic in nature, can form at electrode surfaces by naturally occurring processes or can be deliberately induced to form there. The behaviour of a deliberately formed Ca(OH)2 film on the rate of cathodic hypochlorite reduction in an undivided brine electrolysis cell is examined. The results can be modelled in terms of electrode obscuration and the conditions for film formation and dissolution are also treated. It is shown that the latter is a self‐limiting process.
Desiccant efficiency in solvent drying. Applications of cationic exchange resins
Authors: Burfield David R. , Smithers Roger H.
Published: July 2010

This paper describes the evaluation of activated cation exchange resins as desiccants for solvent drying. Using a previously described radiotracer technique the effect of parameters such as activation temperature, desiccant loading and cation type have been investigated. Comparison with earlier evaluations of molecular sieves are made. Cation exchange resins are found to be moderately efficient and rapid desiccants. Typical equilibrium mositure contents at 5% (w/v) desiccant loadings are dioxane (600 mg dm−3), dichloromethane (10 mg dm−3) and toluene (1 mg dm−3).
Thermal decomposition of zinc zirconyl oxalate pentahydrate
Authors: Reddy V. Butchi , Mohan Rao C. Rama , Mehrotra P. Narain
Published: July 2010

Thermal decomposition of zinc zirconyl oxalate (ZZO) has been investigated employing thermogravimetric, differential thermal analysis and differential thermogravimetric techniques and chemical analysis. The decomposition proceeds through three steps. The first step is the dehydration of the zinc zirconyl oxalate pentahydrate in the temperature range 303–473 K. The second stage is the decomposition of the oxalate giving an intermediate residue containing both oxalate and carbonate between 473–613 K. The third and final stage is the decomposition of the intermediate between 613–833 K to give zinc zirconate. The infrared spectral and X‐ray data confirm the formation of ZnZrO3.
The preparation of thiophenes. II. From C5‐C7‐molecules and carbon disulphide
Authors: Azizian Farid , Pizey James S.
Published: July 2010

Substituted thiophenes have been obtained in high yields by passing C5‐C7‐molecules and carbon disulphide (CS2) over a promoted chromium‐aluminium oxide catalyst (Girdler G41)1 in the vapour phase at 500°C. Both the scope and mechanism of these reactions have been studied using an alkane and a number of alcohols and ketones, and the reaction products have been identified. The reaction of pentan‐2‐ol with 13C‐carbon disulphide (13CS2) has been carried out to study the incorporation of the carbon atom of the CS2 into the thiophene ring.
Hydrogenation of benzene to cyclohexene on a ruthenium catalyst: Influence of some reaction parameters
Authors: Odenbrand C. U. Ingemar , Lundin Sten T.
Published: July 2010

The formation of cyclohexene in the hydrogenation of benzene on a ruthenium catalyst has been studied in a slurry reactor. The reaction was performed in an alkaline aqueous phase in a stirred autoclave of stainless steel. The influence of reaction parameters, e.g. hydrogen pressure, alkali concentration, amount of catalyst and temperature was determined. The influence of poisoning of the catalyst by corrosion products is also discussed.
The formation of anthracene derivatives and substituted diphenylmethanes fromo‐bromobenzyl bromide
Authors: Barnes Ian , Robinson J. Gordon , Marr George
Published: July 2010

o‐Bromobenzyl bromide was converted to 1‐(1‐chloro‐1‐alkyl/aryl) methyldiphenylmethanes which were then treated with aluminium chloride under anhydrous conditions when mixtures of anthracene derivatives and substituted diphenylmethanes were obtained. The size of the alkyl (or aryl) group in the chloro‐methanes influenced the relative yields of the anthracene derivatives to diphenylmethanes.
Kinetics of the exchange between battery‐active manganese dioxides and manganese(II) ions in aqueous solution
Authors: Rophael Magdy W. , Malati Mounir A.
Published: July 2010

The initial rate and the extent of exchange between 56Mn‐labelled dioxides and 0.1M MnSO4 solution at 25°C and pH 5.4 were found to increase in the series: β‐MoO2 (R4), <γ‐MnO2 (R2), < ϵ‐MnO2. The rate of exchange between R2 and 0.1M MnSO4 solution at pH 2.0 was higher than the corresponding results at pH 5.4 but the results were similar at the two pH values when R2 was washed with dilute acid (pH 2.0) prior to the exchange at pH 2.0. The results of the exchange for the size fraction −120 to + 300 mesh of R2 were similar to those for the unsieved R2 under the same conditions. When either R2 or R4 were partially reduced with N2H4·H2O solution prior to the exchange, the results were appreciably higher than those obtained for the unreduced solids—especially in the case of R2. When different concentrations of Mn(NO3)2 solution were used with R2, the percentage exchange increased to a small extent as the concentration increased ten‐fold. The variation of the solid: solution ratio had a minor effect on the extent of exchange between R2 and 0.1M MnSO4 solution.
Adaptation of the liquid chromatograph as a micro‐reactor; immobilised lactase kinetics
Authors: Melton H. Rodger , Bailey David C. , Langer Stanley H.
Published: July 2010

A catalytic, micro‐reactor system has been developed using a modified liquid chromatograph with an ultraviolet spectrophotometer detector. The continuous flow, micro‐reactor method has been adapted to the measurement of the activity of enzyme catalysts immobilised on porous glass beads. The system offers advantages over other systems in terms of convenience and provisions for steady‐state analysis and control. The speed and ease of obtaining reproducible data make it feasible to study the efficacy of immobilisation techniques systematically and to explore liquid chromatographic reactor methods further. The kinetic data obtained were compatible with those found with other methods for the hydrolysis of o‐nitrophenyl‐β‐D‐galactopyranoside with immobilised lactase from the fungus Aspergillus niger.
Conversion of waste plastics to single‐cell protein by means of pyrolysis followed by fermentation
Authors: Karthigesan Jeevajothy , Brown Bernard S.
Published: July 2010

Waste plastics (e.g. polyethylene, polystyrene and polypropylene) have been converted to single‐cell protein using pyrolysis followed by fermentation. Conversion efficiencies of plastics to pyrolysate were 75–90% for polyethylene, 10–56% for polystyrene and 40–50% for polypropylene. Unpyrolysed residues were formed with polystyrene (6–14%) and polypropylene (14–30%), but not with polyethylene. Polyvinyl chloride produced hydrogen chloride fumes, together with 33–39% unpyrolysed residue, no fermentable pyrolysis products being formed. Polyethylene pyrolysate was fermented by the yeast, Candida tropicalis. Batch fermentation was carried out at 31°C and pH 5.5 on polyethylene pyrolysate in shaken flasks (100 cm3 culture) and in an aerated fermenter (500 cm3 culture). Maximum growth rate was 0.168 h−1, cell yield was 0.47 ± 0.02 g g−1 pyrolysate used (n = 3) and doubling time was 4–5 h, after 72 h growth on 1.0g pyrolysate 100 cm−3 culture. Continuous culture (dilution rate 0.10 h−1) gave a dry cell yield of 0.39 g g−1 pyrolysate utilised. Utilisation of pyrolysate was 49.0% in batch culture and 33.0% in continuous culture. The efficiency of conversion of polyethylene to biomass was 34–42% in batch culture. Emulsification and pristane‐solubilisation were studied as a means of dispersing waxy pyrolysates in culture media. Pristane did not support growth whereas the emulsifier [lecithin, Tween 85 and sodium glycocholate (1:2:2 by weight)] could support up to 27% of the growth observed on polyethylene pyrolysate. Although growth would occur without either emulsifier or pristane, use of pristane increased both dry cell yield (g g−1 pyrolysate used) and pyrolysate utilisation by 1.3 times in flask cultures. Crude protein content of cells cultured on polyethylene pyrolysate was 46.7 ± 2.4% (n = 3) for batch culture cells, and 43.8 ± 0.3% (n = 4) for continuous culture cells. The true protein content of Candida cells was about 17%. The protein had a favourable nutritional quality as judged by in‐vitro chemical tests.
Studies on the dehydrocyclisation of n‐octane and gasoline over chromia—alumina—potassium oxide catalyst
Authors: Hassan Shawky M. , Abdou Ismil K. , Roushdi Mohamed I. , Elkadi Gamal M.
Published: July 2010

A non‐acidic chromia‐alumina‐potassium oxide catalyst has been prepared which possesses high thermal stability and stable dehydrocyclisation activity for n‐octane and gasoline. Thermal sintering of the catalyst greatly influences its selectivity. The effect of reaction temperature and space velocity on the product distribution has been studied. At optimum conditions, about 90% (w/w) of n‐octane is converted into aromatics, of which 94% are ethylbenzene and o‐xylene. Of the gasoline fraction (50–130°C), about 75% (w/w) has been converted into aromatics. Octenes and C8‐alkylcyclohexanes detected after dehydrocyclisation of n‐octane are not intermediates in the reaction.
Distribution of trace metals in petroleum and its heavy refinery products
Authors: Abu‐Elgheit Mohamed A. , Elkholy Ibrahim S. , Barakat Assem O.
Published: July 2010

The distribution of trace metals between crude petroleum and its heavy products has been studied by emission spectrography. The highest concentration of V, Ni, Sb and Mg was associated with the asphaltic fraction. A correlation has been established between the V/Ni, V/Sb and Ni/Sb indices and the geologic age of petroleum. Examination of gas and diesel oils for suitability as catalytic cracking feedstocks has been made on the basis of their Ni equivalent. Lubricating oil was found to retain little or no trace metals from the parent crude oil. The relatively high V content of fuel oil can affect refinery equipment, distillation units and linings of industrial furnaces. Other trace metals are non‐destructive or only slightly destructive.
Liquid‐liquid equilibria for toluene‐heptane‐N‐methyl pyrrolidone and benzene‐heptane solvents
Authors: Nagpal Jag M. , Rawat Bachan S.
Published: July 2010

The liquid‐liquid equilibria for toluene‐n‐heptane‐N‐methyl pyrrolidone containing 10 and 20% water at 298 and 313 K, and of benzene‐n‐heptane with N‐methyl pyrrolidone‐ethylene glycol and γ‐butyrolactone‐ethylene glycol, which is a new solvent combination, have been determined at 303 K.
Biosynthesis of carbomycin, its extraction, purification and mode of action on Bacillus subtilis NRRL B‐543
Authors: Baghlaf A. O. , Abou‐Zeid A. Z. A. , El‐Diwzny A. I.
Published: July 2010

A fermentation medium containing (g dm−3)—glucose, 10.0; soyabean meal, 10.0; NaCl, 5.0 and CaCO3, 1.0 in distilled water—was used in the biosynthesis of the macrolide antibiotic carbomycin. Maximum yield of carbomycin was obtained after 120 h fermentation. Carbomycin was extracted by different organic solvents adjusted to different pH values. Extraction of the antibiotic was possible when the pH of the fermentation broth was neutral (6.5–7.5) with all organic acids used, but the most efficient organic solvent suitable for extraction of carbomycin was chloroform at a pH of 6.5. Further purification was carried out by preparative thin layer chromatography. The most efficient separation into carbomycin A and carbomycin B was obtained using a solvent system of ethanol‐hexane‐water [90:10:0.15 (v/v)]. Carbomycin inhibited the biosynthesis of the anabolising cellular constituents phosphoprotein, ribonucleic and deoxyribonucleic acids in Bacillus subtilis NRRL B‐543.
Experimental examination of the room temperature hydrodynamics and electrochemical current‐voltage behaviour of the Bi‐terminated vibrating wire electrode
Authors: Moorhead Edward D. , Bhat Gajanana A. , Stephens Michael M.
Published: July 2010

An experimental study was made of the room temperature hydrodynamics and current‐voltage (I‐V) behaviour of a bi‐terminated transverse oscillating resonant electrode using an adaptation of the electromagnetically‐driven vibrating wire technique recently developed for precise viscosity measurements of cryogenic fluids. For argon, nitrogen, as well as dilute electrolytes, the shapes of the in‐phase and quadrature resonance lines agreed with lines obtained by computer simulation. Although such peaks exhibited shorter heights than predicted (probably due to dispersion or some energy loss to the end terminations), observed peak areas agreed with theory. Use of either 50‐μm diameter platinum or tungsten wires as working electrodes in three‐electrode voltammetry yielded quite well‐defined I‐V curves for reduction of dilute ferricyanide and iodate as test systems, with Fe(CN)6−3 exhibiting near‐Nernstian reversibility at the tungsten wire. Well‐shaped I‐V curves were also obtained for lead (II) reduction on oxide‐free platinum. Resonant platinum wires clad with lead films produced by controlled potential deposition yielded, as expected, an advantageous negative shift in potential for H+ reduction. Because the mechanical properties of soft or low tensile strength metals deny their direct use as resonant electrodes, clad wires, on the other hand, should enable electrochemical, corrosion, and surface studies of such materials to be accomplished under rather precisely controlled conditions.
The pyrolysis of propane. II. Effect of hydrogen sulphide
Authors: Trimm David L. , Turner Christopher J.
Published: July 2010

Hydrogen sulphide has been found to have a significant effect on the rate of carbon formation during the pyrolysis of propane. Studies have been carried out to measure carbon formation on pre‐sulphided foils of nickel, copper, iron and stainless steel, and to measure carbon formation on the metals from a mixture of propane and hydrogen sulphide. No changes could be detected in the gaseous or liquid products of pyrolysis in the presence of sulphides, but carbon formation was either inhibited or accelerated. The formation of stable metal sulphides inhibited carbon formation. The formation and subsequent decomposition of metal sulphides accelerated carbon formation.
Synthesis of antimicrobial heteroaryl‐substituted‐1,2,3‐triazolines via the reaction of diazomethane with anils and mixed azines of thiophenealdehyde and/or isatin
Authors: Youssef Mohamed S. K.
Published: July 2010

Diazomethane was reacted with nitro‐substituted anils of thiophenealdehyde and/or isatin and with some unsymmetric azines. 1,2,3‐Triazolines were obtained in all cases. Product constitution is discussed. Some of these were found to inhibit the development of a range of Gram‐positive and Gram‐negative bacteria.
Adsorption of ionic and non‐ionic surfactants by wool charring waste
Authors: Perineau Francis , Gaset Antoine
Published: July 2010

The effect of pH and temperature on the adsorption of anionic, cationic, and non‐ionic surfactants on wool charring waste has been investigated in order to assess the optimum conditions of substrate use in water pollution control. The analysis of adsorption kinetics in aqueous media and in water‐alcohol mixtures, allowed different adsorption mechanisms to be characterised. Plots of the amount of surfactant adsorbed against the square root of time provided information on the diffusion processes. The effect of the chain length on the adsorption of alkylsulphates on wool charring waste corroborated the importance of hydrophobic interactions.
Synthesis of 5‐hydroxymethyl‐2‐furancarboxaldehyde catalysed by cationic exchange resins. Part 1. Choice of the catalyst and the characteristics of the reaction medium
Authors: Mercadier Daniel , Rigal Luc , Gaset Antoine , Gorrichon Jean‐Pierre
Published: July 2010

In this preliminary study, it was shown that strong acid ion exchange resins allowed the dehydration of D‐fructose to 5‐hydroxymethyl‐2‐furancarboxaldehyde at mild temperatures and pressures. Evidence was given that the use of a solvent (i.e. methyl isobutylketone) with high extracting power toward the obtained compound improved the yield of this reaction. In order to take into account the treatment of aqueous solutions of sugars as well as the peculiar use of ion exchange resins, particularly a good hydration mode, a water:solvent ratio of 1:9 was chosen. These conditions were shown to lead to satisfactory yields and conversion rates.
A theoretical analysis of the deactivation of an immobilised enzyme in multi‐enzyme reactions in fixed‐bed and fluid‐bed reactors
Authors: Sadana Ajit
Published: July 2010

The effect of time‐averaging on the selectivity to an intermediate R (yR) and the yield to product S (yR) in a consecutive reaction A→R→S, occurring in a deactivating fixed‐bed reactor, has been examined. Time‐averaging smooths the selectivity and increases the yield for high values of the deactivation (λ) and reaction (δ) parameters. The kinetics and dynamics of yR and yS in a deactivating steady‐state fluid‐bed reactor were also examined. Both non‐selective and selective deactivation are considered. The practical implications of the development are considered in terms of an example, in which the values chosen for parameters are arbitrary though reasonable with respect to experimental values.
Ternary phase equilibrium studies of the system: Tetrahydrofuran‐water‐alcohols
Authors: Patel Amrit N.
Published: July 2010

Ternary phase equilibrium data for tetrahydrofuran (THF) with water and butan‐1‐ol, 2‐methylpropan‐1‐ol, pentan‐1‐ol, cyclohexan‐1‐ol and benzyl alcohol are presented and used to evaluate the possibility of employing the distribution of THF between water and these alcohols as a means of separation of THF from aqueous solutions. The tie‐line data for the systems have been correlated and the plait‐points have been located.