bluuebunny/crossref_metadata_2025 huggingface dataset:
A mechanistic model of a packed‐bed electrode cell to remove metal ions from dilute effluent solutions
Authors: Bryson Anthony W. , Dardis Kevin A.
Published: July 2010

A mathematical model of a porous cathode cell is derived in terms of fundamental kinetic parameters for the deposition of metals from dilute solutions. The model is used to design a pilot plant to treat electroplating waste effluents. Experimental results show that the plant can reduce the concentration of copper, nickel, chromium and zinc by at least 90% at acceptable current efficiencies.
The characterisation and evaluation of highly dispersed tungsten carbide electrocatalysts
Authors: Miles Richard
Published: July 2010

The suitability of using highly dispersed tungsten carbide as an inexpensive alternative catalyst to platinum for use in methanol fuel cells has been investigated. The results show that tungsten carbide possesses no activity for the methanol electro‐oxidation reaction. Of the tungsten carbide samples examined only those treated with molybdenum produced any measurable oxidation current. Formaldehyde, however, is oxidised on tungsten carbide though the activity is several orders of magnitude lower than that of platinum catalysts. In the potential region where the electro‐oxidation of methanol and formaldehyde takes place there is significant corrosion of the tungsten carbide catalyst in aqueous sulphuric acid electrolyte, rendering it unsuitable even as a support for platinum.
Phase equilibria in ammonia—carbon dioxide systems at and above urea synthesis conditions
Authors: Lemkowitz Saul M. , Van Erp Jan C. , Rekers Domien M. , Van Den Berg Pieter J.
Published: July 2010

A comprehensive temperature‐pressure‐composition phase model is presented which combines all known phase equilibria relating to the binary ammonia‐carbon oxide system (no urea present) at urea synthesis conditions. The bubble‐points and critical‐points of the ammonia‐carbon dioxide section of the ternary ammonia‐water‐carbon dioxide system at chemical equilibrium (urea present) have been measured up to the values of NH3/CO2 = 2, T = 280°C, and p = 2000 atm. The critical temperature and pressure values of a NH3/CO2 = 2 mixture, of importance to the theory describing the maximum conversion to urea, have been found to be 276°C and 1250 atm, respectively.
Mannich bases of 2‐aminothiazoles
Authors: Badr M. Zarif A. , Aly Morsy M. , El‐Naggar Galal M.
Published: July 2010

Synthesis of some new Mannich bases, 2(thiazolylaminobenzyl)‐1‐naphthols (I) and 1(thiazolylaminobenzyl)‐2‐naphthols (II) are described. Condensation of 4,5‐disubstituted‐2‐aminothiazoles and the appropriate aldehyde with 1‐naphthol gives (I), while condensation with 2‐naphthol gives (II). Their structures have been ascertained by spectroscopy and by synthesis from the dibromoderivative of 2‐arylidene‐1‐tetralone and the corresponding 2‐aminothiazole.
Re‐use and separation of waste plastics
Authors: Lindfors Lars G.
Published: July 2010

Commercial and pilot‐scale methods for the re‐use of clean, unmixed scrap plastic are described. Mixed scrap presents greater problems and efforts have been made to improve its properties with additives or by altering its composition. Separation methods are surveyed. Mixed wastes find limited re‐use in low quality products. Re‐use of waste plastics as fuel is now probably the most economical alternative. Economic rather than technical obstacles remain for this recycling.
Interactions between an electrochemical reactor and associated unit processes
Authors: Plimley Raymond E.
Published: July 2010

It is shown that in the presence of interactive variables, the optimum operating conditions for a reactor cannot be determined in isolation from its associated unit operations. The argument is illustrated by a process model developed for a continuous electrochemical reactor linked to a distillation unit which recycles unconverted feedstock. The model reveals that if conditions in the distillation unit are ignored a false optimum well removed from the true optimum would be identified.
The hydrolysis of brilliant green and some derivatives. I. A kinetic and equilibrium study of the hydrolysis of brilliant green
Authors: Fox Brenda M. , Hallas Geoffrey , Hepworth John D. , Mason Donald
Published: July 2010

The hydrolysis of Brilliant Green has been studied over the pH range 6–11. In neutral aqueous solution and in the absence of light, the system reaches equilibrium. In alkaline solution, complete conversion into the dye base occurs. Rate constants and activation parameters have been obtained for the hydrolysis and a reaction scheme is proposed.
Adsorption of streptomycin on ion exchange resins: Equilibrium and kinetic studies
Authors: Prasad Rajendra , Gupta Ashok K. , Bajpai Rakesh K.
Published: July 2010

Equilibrium and kinetic studies of streptomycin adsorption from aqueous solutions of streptomycin sulphate were carried out using four weakly acidic ion exchange resins: Indion 236 [Ion Exchange (India) Ltd], Amberlite IRC‐50 (Rohm and Haas Co, USA), KB‐2 and KB4‐P2 (both Russian resins), initially in the sodium form. The maximum amounts of streptomycin taken up by the exchangers were about 1640, 1560, 2050 1400 mg g−1 dry resin (sodium form), respectively. The rate of adsorption of the antibiotic was highest with the ion‐exchanger KB‐2, and lowest with KB4‐P2. The initial diffusivity values calculated for the four exchangers at a temperature of 9°C were 2.87 × 10−8, 1.87 × 10−8, 3.42 × 10−8 and 0.468 × 10−8 cm2 s−1, respectively.
Methane production from acids in piggery‐waste digesters
Authors: Hobson Peter N. , McDonald Ian
Published: July 2010

Results from piggery‐waste digestion fit those from a continuous culture of acetate utilising methanogenic bacteria showing that the acid to methane step of this digestion can be regarded as an independent continuous culture behaving as predicted by a simple continuous culture model with a wash‐out dilution rate of about 0.4 day−1 and a Ks value of about 800–900 mg acetic acid dm−3. However, this was only possible because the waste contained a high concentration of free acid and the application of the results to other digestions is discussed.
Catalysed hydrogenation of hydroxynitroanthraquinones in strong acid
Authors: Morley John O. , Hutcheson Raymond
Published: July 2010

The catalytic hydrogenation of hydroxynitroanthraquinones such as 1,8‐dihydroxy‐4,5‐dinitroanthraquinone over either palladium‐carbon or platinum‐carbon catalysts proceeds readily in 75% sulphuric acid at 125°C during 6–12 h at 100 kPa pressure to give the corresponding aminohydroxyanthraquinones in high yield. Catalyst recoveries are excellent. A combined process has been developed to give diaminochrysazin in 93% overall yield by a combined nitration of chrysazin and in situ catalytic reduction of the nitration liquors.
Microbial production of L‐lysine
Authors: Misra Anjani K. , Dasgupta Jyotirmoy , Vora Vinay C.
Published: July 2010

The production of lysine by fermentation was studied, using a homoserine‐deficient and aminoethylcysteine‐resistant strain of Corynebacterium glutamicum, in 1‐dm3 shake flasks and a 14‐dm3 laboratory fermentor. Molasses was used as substrate. Superphosphate‐treated black strap molasses gave better lysine production. Lysine production, residual sugar and dry cell mass were measured as a function of fermentation time. It was observed that 1 g of cell mass produced 3.36 g of lysine.
Recovery of titanium dioxide from naturally occurring ilmenite by high‐temperature borate fusion
Authors: Easteal Allan J. , Morcom Anthony T.
Published: July 2010

Fusion of naturally‐occurring ilmenite at 1273 K with Li2O·XB2O3 solvents (where X = 2, 4, 5, 6, 7 and 8) gives, after boiling water extraction of the crushed solidified melts, maximum (68.1%) recovery of TiO2 (as rutile) for X = 6. Extraction with hot 9 mol dm−3H2SO4 of the water‐insoluble residue from the fusion of ilmenite with Li2O·6B2O3 yields a product containing 86 weight % TiO2 and only a trace of iron. The overall process is a possible route for upgrading ilmenite to a rutile‐enriched product.
Catalytic activity of pure and doped ceria
Authors: Fahim R. B. , Zaki M. I. , Gabr R. M.
Published: July 2010

Structural and phase changes accompanying the thermal dehydration of pure and doped hydrated eerie oxide have been followed by thermogravimetric analysis, differential thermal analysis, and X‐ray diffraction studies. Doping has been affected by either Zn2+, Al2+ or U6+ ions. Texture investigation has been studied by analysis of nitrogen adsorption isotherms. Variation in porosity due to annealing and/or doping, as well as mechanisms of foreign ion incorporation, have been correlated with catalyst activity towards decomposition of isopropanol.
Extraction of uranium (VI) by di‐(2‐ethylhexyl)phosphoric acid gels based on a styrene‐divinylbenzene copolymer
Authors: Shakir Kamal , Beheir Shokry G.
Published: July 2010

Uranium (VI) can be efficiently extracted using hydrophobic gel particles prepared by swelling styrene‐divinylbenzene copolymer beads with di‐(2‐ethylhexyl)phosphoric acid packed into columns. Retained U (VI) can be quantitatively eluted with acid solutions. The effects of incorporating different organic solvents into the gel on its capacity and performance have been investigated. It was found that nitrobenzene gave the best results. The conditions required for the preparation of gels of high capacity have been established.
Electrical control and optimisation of the electrochemical batch reactor
Authors: Kreysa Gerhard
Published: July 2010

For galvanostatic, potentiostatic and constant cell voltage control, parameters such as conversion degree, energy efficiency, space‐time yield, specific energy consumption and their time‐dependencies have been calculated for a diffusion‐controlled reaction in an electrochemical batch reactor. Comparison of the results showed that potentiostatic control is the most efficient operation mode, but that constant cell voltage control is more useful and provides a similar efficiency. Some results from model calculations were compared with those from laboratory experiments. A numerical optimisation procedure was applied to an electrochemical batch reactor with constant cell voltage control. The resulting optimum batch electrolysis time, the optimum conversion degree, and the minimum costs were calculated as functions of the initial reactant concentration, specific electrode surface area, costs of raw materials and investment costs.
Quantitative effect of gritty contaminants on the sensitiveness of high explosives to ignition by impact. Probabilistic calculations via the K‐parameter
Authors: Scullion Henry J.
Published: July 2010

Tests on contaminated high explosives afford values of K in the equation. Which are used to calculate, inter alia, the probability of a hot‐spot precursor (HSP) with specific grits at selected levels, the mean mass of grit for one HSP, and the initial (i.e. ‘zero’ grit) rate of fall in insensitiveness with increasing contaminant.
Design concepts and construction of bipolar filterpress cells
Authors: Birkett Michael D. , Clarke Robert L. , Kuhn Anselm T.
Published: July 2010

The design concepts used in the construction of bipolar parallel plate cells for aqueous electrolysis are critically considered.
Compositional study of crude oils using fourier transform n.m.r. Characterisation
Authors: Srivastava Shanti P. , Singh Indra Deo
Published: July 2010

The Fourier transform (FT) 1H‐ and 13C‐nuclear magnetic resonance (n.m.r.) spectra of three crude oils have been recorded at room temperature on a Jeol pulsed FT‐n.m.r. spectrometer. The branchiness index has been calculated from 1H‐n.m.r. spectra and the percentage of aromatic carbons (% CA) from the 13C‐spectra. The results are discussed and the usefulness of n.m.r. techniques in such studies considered.
Surface texture of strontium carbonate
Authors: Amin Anwar , Selim Suzy A.
Published: July 2010

Two batches of strontium carbonate (SrCO3) prepared at temperatures ⩽333 K (A) and 373 K (B) were investigated using differential thermal analysis (DTA), thermogravimetric (TG), X‐ray diffraction (XRD) and N2 adsorption techniques. Heat treatment up to 1073 K causes no material decomposition of the carbonate and DTA and TG results indicate impurity action. XRD patterns of both samples though slightly different at low temperatures, are identical with orthorhombic SrCO3 above 773 K. The N2 specific surface area of sample B is about three times that of sample A. Thermal treatment of batch A shows two regions of area development resulting from two different types of entrapped water whereas batch B shows only one region and contains only one type of entrapped water. Both samples and their decomposition products are predominantly lyophobic towards cyclohexane adsorption. With sample A the parent material was mesoporous. These pores widen at 423 K due to growth in grain size, but narrowing commences with the evolution of area at 573 K. At temperatures ⩾ 773 K the pores widen again. Sample B contains both micro‐ and mesopores with the latter dominating at higher temperatures where sintering operates.
Studies on the use of chromium ferrocyanide gels in the treatment of radioactive wastes
Authors: Srivastava Suresh K. , Bhattacharjee G. , Kumar Satish , Oberoi Chander K. , Sharma Ashok K.
Published: July 2010

The sorption and distribution of some radioisotopes on chromium ferrocyanide gels under different physical conditions has been investigated. The exchanger shows high selectivity for Tl+, Cs+, Cd2+ and Pb2+. A complete elution of Cs+, Tl+ and Rb+ is possible with suitable eluants whereas Pb2+ and Cd2+ cannot be desorbed. The uptake of monovalent ions is by an ion exchange process unlike the sorption of bivalent ions.
An interpretation of proton acidity and its relevance to catalysis in low sodium content Y zeolites from studies of heats of immersion in methanol
Authors: Coughlan Brendan , Carroll William M. , Kavanagh Patrick , Nunan John
Published: July 2010

The interrelationship of acidity and catalytic activity in reactions involving carbonium ions in zeolite‐type catalysts has been studied. Heats of immersion of a range of HNaY zeolites in methanol at 293 K are presented. It has been shown that the interaction energy of the basic methanol molecule with the zeolite framework reflects the acid nature of the zeolite surface and this is correlated with catalytic results for the competitive ethylation of toluene and benzene, and also for cracking and isomerisation reactions. Assessment of acidity in decationated zeolite catalysts by this method should prove useful where other methods of measurement of acidity prove difficult.
Studies in the adsorption and diffusion of ions in chitosan
Authors: Blair Hal S. , Ho Ting‐Chung
Published: July 2010

Chitin was obtained from shell of the tail portions of the prawn Nephrops norvegicus (L) and was deacetylated to give chitosan. The adsorption and diffusion of copper (II) ions were studied and the diffusion of the acid dye CI Acid Orange 10 through chitosan films containing different amounts of chelated copper was investigated. It was found that with increasing copper content the rate of diffusion through the membrane decreased.
Single‐cell protein from methanol: Economic aspects of the norprotein® process
Authors: Ericsson Magnus , Ebbinghaus Lars , Lindblom Marianne
Published: July 2010

Norprotein is a subsidiary of the Norwegian chemical group Norsk Hydro A.S and the Swedish food company AB Marabou. Since 1974 the main activity of research has been to develop a process for single‐cell protein production from methanol. At present, research activities are directed towards finding alternative applications for the developed technology within the field of biotechnology.
Bioconversion of Macrocystis pyrifera to methane
Authors: Ghosh Sambhunath , Klass Donald L. , Chynoweth David P.
Published: July 2010

Methane production by anaerobic digestion of kelp is a relatively new approach to augmenting the national gas supply. Digestion of the giant marine kelp Macrocystis pyrifera, investigated in a series of bench‐scale experiments at the Institute of Gas Technology (IGT), is reported. Conducted with both untreated and chemically pretreated plants, the tests have evaluated the effects of major limits on bioconversion of kelp, including temperature, indigenous salt concentration, external nutrients, inocula source, loading, residence time, manner of mixing and frequency of feeding. A detailed chemical characterisation of the kelp samples is presented. Raw‐kelp digestion was not limited by nitrogen or phosphorus. Temperature ranges of 35–40°C and 50–55°C were found to be optimum for mesophilic and thermophilic digestion of raw kelp. The mesophilic methane yield in the semicontinuous mode was about 4.5 SCF/lb (280.94 cm3 g−1) of volatile solids (VS) added compared with a thermophilic methane yield of 2.4 SCF/lb (149.83 cm3 g−1) of VS added. The mesophilic organisms could be acclimatised to a salt concentration that has a conductivity of 43 000 μmho cm−1 without any deleterious effect. Thermophilic methanogens were more sensitive to high salt concentrations than the mesophilic organisms. Raw kelp had an estimated ultimate biodegradability of 80%. Mannitol and algin were the most biodegradable components.
Kinetics of two‐phase reduction of aromatic nitro compounds by aqueous solutions of sodium sulphides
Authors: Bhave Ramesh R. , Sharma Man M.
Published: July 2010

The kinetics of two‐phase reduction of aromatic nitro compounds (e.g. m‐chloronitrobenzene, m‐dinitrobenzene and p‐nitroaniline) by aqueous solutions of sodium monosulphide and sodium disulphide was studied in a mechanically‐agitated glass contactor. For p‐nitroaniline, the effect of temperature in the range of 333 K to 363 K was studied. Diffusional resistance could be eliminated. The reaction between the dissolved nitroaromatic and sulphide species was found to be first‐order with respect to the nitroaromatic concentration and first‐order with respect to the sulphide concentration. The value of the activation energy for p‐nitroaniline was found to be 55.2 kJ mol−1. The values of the second‐order rate constant for a variety of nitroaromatic compounds, which varied by a factor of 150, have been correlated by the Hammett's equation.
A vapour‐liquid equilibrium model of the NH3CO2H2O‐urea system at elevated pressure
Authors: Kotula Edward
Published: July 2010

Vapour‐liquid equilibrium measurements on the NH3CO2H2O‐urea system within the operating range of the absorption and condensation steps of the recycle urea process have been made. From the Margules formulae, a generalised formula for activity coefficients of components in multicomponent system has been derived. Equations for NH3 and H2O partial pressures over solutions of the system investigated were developed using the Raoult's law and an ionic equilibrium principle.
The preparation of 5‐hydroxymethylfurfuraldehyde from high fructose corn syrup and other carbohydrates
Authors: Szmant H. Harry , Chundury Deena D.
Published: July 2010

5‐Hydroxymethylfurfuraldehyde (HMF) was prepared from high fructose corn syrup (HFCS), or crystalline D‐fructose, in high yield and purity. A 95–97% conversion of fructose to HMF was achieved using 25 mol% (based on fructose) boron trifluoride etherate catalyst in dimethyl sulphoxide, under a nitrogen atmosphere, a reaction temperature of 273 K and 30 min reaction time. Inferior yields of HMF were obtained from glucose and starch.
The pyrolysis of propane. I. Production of gases, liquids and carbon
Authors: Trimm David L. , Turner C. J.
Published: July 2010

Studies have been carried out on the formation of gases, tars and carbon from the pyrolysis of propane under conditions pertinent to steam cracking. Careful analysis has been carried out to relate the production of gases, liquids and solids in the presence and absence of hydrogen and helium diluents. The experimental observations agree with predictions of gas production from a mathematical model. The reactor surface is shown to influence the production of carbon and possibly the production of gases and tars. Minimisation of coke formation in steam cracking is shown to depend, at least in part, on the correct choice of material for reactor construction.
Extraction of copper from acid sulphate solutions by 2‐hydroxy‐5‐n‐nonyl and 2‐hydroxy‐4′‐n‐nonylbenzophenone oximes
Authors: Goszczyński Stefan , Szymanowski Jan , Borowiak‐Resterna Aleksandra
Published: July 2010

The study of copper extraction shows that the position of the chain (5 or 4′) does not influence the statics of copper extraction from ammonia solutions by alkyl derivatives of 2‐hydroxybenzophenone oxime. Acid solutions of 2‐hydroxy‐4′‐n‐nonylbenzo‐phenone oxime can extract more copper than 2‐hydroxy‐5‐n‐nonylbenzophenone oxime, but less than 2‐hydroxy‐5‐n‐alkylbenzaldehyde oxime.
A kinetic study of the metathesis of propene on a rhenium‐aluminium catalyst
Authors: El‐Sawi Mahmoud , Iannibello Antonio , Morelli Fernando , Gatalano Ganfranco , Intrieri Francesco , Giordano Girolamo
Published: July 2010

Based on integral kinetic measurements and in accordance with the results of previous investigations, two mechanistic initial rate expressions based on different reaction mechanisms have been found to be statistically equivalent. Applying the Boudart criteria in a test for the physical significance of the parameter estimates, only one of the suggested expressions is significant and the corresponding reaction mechanism is, therefore, considered adequate.
The external mass transfer of basic and acidic dyes on wood
Authors: McKay Gordon , McConvey Ian F.
Published: July 2010

The parameters affecting the initial adsorption rates of Astrazone Blue dye (Basic Blue 69) on to wood have been studied. A simple model has been proposed to determine the external mass transfer coefficients and these have been compared with values obtained using a more complex procedure. The external mass transfer coefficient, β, has been shown to vary linearly with agitation and initial dye concentration using log‐log coordinates; furthermore β is independent of particle size. The effect of temperature has been studied and the activation energy for the process is 44 ± 2 kJ mol−1. Similar correlations were obtained for the adsorption of Telon Blue dye (Acid Blue 25) on wood. Using log‐log correlations, the external mass transfer coefficient was found to vary with (rev min−1)0.14,C0−0.27; and a small dependence on particle size was also observed. The activation energy for the external mass transfer process was 25 ± 2 kJ mol−1.
Synthesis of 5‐hydroxymethyl‐2‐furancarboxaldehyde catalysed by cationic exchange resins. Part 2. Analysis and discussion of the effect of the main parameters on the HMF output
Authors: Mercadier Daniel , Rigal Luc , Gaset Antoine , Gorrichon Jean‐Pierre
Published: July 2010

The effects of the sugar and catalyst concentrations on the dehydration reaction of D‐fructose to 5‐hydroxymethyl‐2‐furancarboxaldehyde when a triphasic medium water‐solvent‐ion exchange resin is used, are described.
Development of a correlation between the non‐polar solubility parameter, refractive index and molecular structure. II. Aliphatic ethers and alcohols
Authors: Wingefors Stig
Published: July 2010

A relationship between the non‐polar solubility parameter (λ) for polar aliphatic solvents and their refractive index has been developed. The use of structural group increments for branched isomers avoids the ambiguous choice between similarity in structure, reduced temperature and molal volume for the polar compound and its hydrocarbon homomorph. For straight‐chain compounds, where a direct comparison with λ as calculated from a homomorph correlation function is possible, the mean discrepancy in λ is 0.07% for ethers and 0.14% for alcohols at 25°C.
Analysis of multiple steady states of complex biochemical reactions
Authors: Ramachandran P. A. , Kulkarni B. D. , Sadana Ajit
Published: July 2010

A general theory for the identification of criteria within which an enzymic reaction can exhibit multiplicity (i.e. multiple steady states) is reviewed. Application of the theory to four types of kinetic models encountered in biochemical reactions is illustrated and figures are presented to delineate the region of multiplicity. The stability of the steady states is analysed for small perturbation about the steady state.
Semiconductor‐electrochemical aspects of bacterial leaching. I. Oxidation of metal sulphides with large energy gaps
Authors: Tributsch Helmut , Bennett Josè C.
Published: July 2010

Thiobacillus ferrooxidanshas been cultivated successfully on synthetic metal sulphides with large energy gaps (CdS, ZnS) as the only energy source for many culture generations during a period of 4 years. The results obtained, which were quantitatively evaluated by calculations of electron transfer probabilities, show that a direct electron transfer from the metal sulphide valence band to the bacterial metabolic system (hole injection into the valence band of the sulphide) has to be excluded as the cause for the enhanced oxidative dissolution for energetic reasons. A detailed analysis of the dynamics of the metal sulphide aqueous electrolyte interface reveals that protons are involved in the mechanism on which bacterial activity is based. By reacting chemically with the metal sulphide surface they break chemical bonds and shift electronic states energetically into the forbidden energy gap to produce surface states which can be chemically described as −SH∂ groups. These control the rate of dissolution of the metal sulphide and are removed by bacterial activity. In this way the proton is recycled and its action can be considered catalytic. For sulphides in which the valence band of the semiconductor is derived from metal orbitals instead of from sulphur orbitals, this mechanism is bound to fail. MoS2and WS2are discussed as examples of such metal sulphides which are not a suitable energy source for bacteria. Some kinetic aspects of the bacterial surface reaction are discussed.
Liquid phase oxidation of p‐xylene to terephthalic acid by air in the absence of a promoter
Authors: Srivastava Krishna K. , Chandalia Sampatraj B.
Published: July 2010

Liquid phase oxidation of p‐xylene to terephthalic acid by air in the presence of solvent acetic acid and a relatively large amount of cobalt acetate as catalyst has been investigated in the absence of any promoter at 100–130°C and a pressure of 2.5–10 kg cm−2. The effect of temperature, catalyst concentration, p‐xylene concentration, air flow rate, pressure, reaction period and addition of small amounts of zirconium salts, etc., on the conversion to terephthalic acid has been studied. p‐Toluic acid, which is an intermediate in the process, was the only major by‐product. The possibility of recycling the mother liquor after the separation of the product was ascertained.
Use of microbial enzyme and cell preparations to synthesise oligopeptide antibiotics
Authors: Vandamme Erick J.
Published: July 2010

Microbial enzymes and cells (in free or immobilised form) have so far been applied mainly in hydrolysis and bioconversion reactions, but recently there has been an increasing interest in the use of such ‘controlled catalytic biomass’ to produce fermentation products and to apply the principle to organic synthesis. Particular attention is given here to the use of immobilised enzymes and cells for producing known or new peptide antibiotics. An evaluation is presented of the applicability of this concept in the fascinating field of peptide antibiotic bioconversions and fermentations. As an important example of the use of enzymes or cells to convert peptide antibiotics into useful derivatives, free and immobilised penicillin acylases, producing the penicillin nucleus 6‐amino‐penicillanic acid, are reviewed as well as their potential to synthesise semi‐synthetic penicillins and cephalosporins. The action of acetylesterase and α‐amino acid ester hydrolase on cephalosporin compounds is also discussed. Use of enzymes and cells to synthesise antibiotics as an alternative method to conventional fermentation is subsequently reviewed. The concept of total enzymic synthesis in vitro of antibiotics is illustrated in the exploitation of the ‘multi‐enzyme thiotemplate mechanism’ of Bacillus brevis, to produce gramicidin S. Total synthesis of peptide antibiotics with immobilised living cells or mycelium as catalysts has been demonstrated recently in the cases of penicillin and bacitracin. These examples of complex multi‐step enzyme reactions might indicate the vast potential of immobilised enzyme and cell technology in fermentation, in biotechnological processes and in organic synthesis.
Preparation of aluminium hydroxide by reacting sodium aluminate solutions with mineral acid
Authors: Sato Taichi
Published: July 2010

The preparation of aluminium hydroxide from sodium aluminate solutions by varying the alkaline concentration at a fixed molar ratio of Na2O: Al2O3 has been investigated on addition of hydrochloric or nitric acids. The resulting materials have been examined by X‐ray diffraction study, infrared spectrophotometry, thermogravimetrical and differential analyses. As a result, it was found that precipitates generally exist as pseudoboehmite or bayerite, but the formation of bayerite is enhanced by a low rate of addition of acid, higher temperature or higher alkaline concentration. In this case, the composition of the precipitates was little influenced at different molar ratios of Na2O: Al2O3. When the precipitates from sodium aluminate solutions at low and higher alkali concentrations were aged in the mother liquors, pseudoboehmite therein transformed to hydrargillite and bayerite, respectively.
Homogeneous reduction of aromatic nitrocompounds by a triphenylphosphine complex of palladium
Authors: Banerjee Tapan Kr. , Sen Debrata
Published: July 2010

The complex Pd2(PPh3)2Cl4 has been used as a homogeneous catalyst for the reduction of C6H5NO2 and p‐ClC6H4NO2 in basic ethanol. A reaction intermediate [Pd(PPh3) (C6H5NO2)Cl2] has been isolated and characterised. Reduction of C6H5NO2 produced aniline (75%), azobenzene (5%) and azoxybenzene (15%) under conditions of atmospheric pressure, while under conditions of high pressure the reduction product contained aniline (95%) only. The yield of p‐ClC6H4NH2 was highest (75%) at normal pressure and decreased with increasing pressure.
Comparison of various methods to determine kinetic constants for β‐galactosidase in soluble and immobilised states
Authors: Peter J. , Prenosil J. E. , Bourne J. R.
Published: July 2010

The graphical methods of Lineweaver—Burk, Eadie, Hanes and the ‘direct linear plot’ have been used to determine the kinetic constants of β‐galactosidase in soluble and immobilised states. Because some of these methods require a reciprocal concentration scale, the activity values obtained from dilute substrate solutions are weighted more than when using more concentrated substrates. However, in the case of immobilised enzymes the values from dilute substrate are more affected by diffusion from the bulk solution into the pores where the enzyme is fixed, and vice versa. Therefore it, seems preferable to use methods with direct substrate and velocity scales. The direct linear plot method is recommended because it does not require any transformation of the measurements, the area of intersection points indicates the accuracy of the measurement and runaway points are easily detected.
Homogeneous hydroformylation of cyclohexene with bis(acetylacetonato)diaquo cobalt (II)
Authors: Banerjee Tapan K. , Saha Chitta R. , Sen Debabrata
Published: July 2010

Hydroformylation of cyclohexane by bis(acetylacetonato)diaquo cobalt(II) [Co(acac)2 (H2O)2] in benzene solution produced the corresponding aldehyde, alcohol and saturated hydrocarbon. The influence of various experimental conditions on the product distribution has been investigated and the optimum conditions for the maximum yield of aldehyde (45%) and alcohol (55%) have been established. A tentative mechanism for hydroformylation has been suggested on the basis of the isolated green complex [Co(acac)2]2(C6H10) having catalytic activity comparable with Co (acac)2(H2O)2 which has been isolated from the product mixture and also synthesised separately.
The preparation of pyrographite‐coated carbon paper by pyrolysis of methane on resistively heated cellulose‐based carbon paper
Authors: Attwood P. A. , Dixon A. G. , Houston A. C. , Short R. T.
Published: July 2010

A laboratory technique has been developed for depositing a layer of pyrographite on to a cellulose‐based carbon‐fibre paper substrate by direct resistive heating in a methane/argon atmosphere, thereby enhancing its electrical conductivity and mechanical strength. The material can be used as a support for methanol electro‐oxidation catalysts and has proved to be a satisfactory replacement for a proprietary material which is no longer available.
The estimation of solubility parameters and related properties of liquids
Authors: McGowan John C.
Published: July 2010

The characteristic pressure, Px (=4.455×109 Nm−2), appears to be the same for all unassociated liquids, and the characteristic volume, Vx, may be found by the addition of atomic factors. The van der Waals constant a, latent heat of evaporation Δ1gHE and solubility parameter can all be estimated for such liquids, since a, Δ(Δ)gHE‐RT) V and δV equal Fx1/2Vx/3, where T is the temperature, R is the gas constant, and V=M/(∂L0‐∂g0): M is the molecular mass; ∂L0 is the density of the liquid and ∂g0 the vapour density. Molecular attraction constants used for the estimation of solubility parameters can be obtained by the multiplication of Vx by the constant Px1/2/3.
The effect of potassium and sodium sulphates on the reaction of synthetic anhydrite with water
Authors: Wilding Christopher R. , Mile Brynmor , Vincent Arthur T.
Published: July 2010

Studies of the effects of the concentration of two additives K2SO4 and Na2SO4 on the hydration of synthetic anhydrite are presented which show the occurrence of broad optimisation maxima. By employing a novel in‐situ precipitation technique, substantial increases in the initial rate of hydration have been achieved.
A convenient preparative method for 2,4‐dialkyl‐2‐cycloalkenyl‐γ‐butyrolactones
Authors: Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi , Ishikame Keinosuke , Sugahara Kotoji
Published: July 2010

Several, 2,4‐dialkyl‐2‐cycloalkenyl‐γ‐butyrolactones were synthesised from 2‐(cycloalken‐1′‐yl) carboxylic acids and epoxides using lithium naphthalenide in the presence of diethylamine. From 2‐(cyclohexen‐1′‐yl)propanoic acid and propylene oxide, 4‐hydroxy‐2‐(cyclohexen‐1′‐yl)‐2‐methylpentanoic acid was obtained. The latter easily cyclised to give 2‐(cyclohexen‐1′‐yl)‐2,4‐dimethyl‐γ‐butyrolactone. Similarly, 2,4‐dialkyl‐2‐(cycloalken‐1′‐yl)‐μ‐butyrolactones were prepared from other 3,4‐unsaturated carboxylic acids and epoxides. These lactones may be used as perfumery materials.
Influence of hydrogen bonding acceptor basicities of esters and ketones on the extraction of acetic and butyric acids from aqueous solutions
Authors: Hegazi Mohamed F.
Published: July 2010

Extractions of acetic and butyric acids from aqueous solutions by various concentrations of carbonyl‐containing compounds dissolved in toluene were carried out at 30°C. The studied compounds included acetone, acetophenone, 2‐butanone, cyclohexanone, methyl, ethyl and iso‐amyl acetates, and mesityl oxide. The observed distribution ratios allowed the evaluation of association constants for the formation of carboxylic acid‐carbonyl‐containing compound complexes. These association constants correlate with the hydrogen bonding acceptor basicities of the esters and ketone used. The implementation of these results are discussed.
The catalytic decomposition of 4‐phenyl‐1,3‐dioxan on copper‐based catalysts
Authors: Červený Libor , Wurzlová Anna , Marhoul AntoníN , Růzika Vlastimil
Published: July 2010

Transformations of 4‐phenyl‐1,3‐dioxan on copper‐based catalysts were investigated in an integral flow reactor in the gas phase in the temperature range 220–280°C. The main products of splitting were 3‐phenylpropanal, 3‐phenylpropan‐1‐ol and allylbenzene, and in some cases, styrene. Suitable reaction conditions were sought for the preparation of 3‐phenylpropanal and allylbenzene from 4‐phenyl‐1,3‐dioxan.
The influence of iron in synthetic zeolites on the decomposition of perborate
Authors: Burriesci Nicola , Giordano Nicola , Petrera Michele , Bart J. C. J.
Published: July 2010

Commercial Grace 4A Zeolite exchanged with Fe3+ ions, pumice from different geological flows and their hydrothermally derived zeolites have been characterised as to the distribution and structural configuration of the iron content. Decomposition capacity of perborate (active constituent of detergent formulations) is not only determined by the total Fe content of the zeolite but also by the oxidation state, electron configuration and coordination. For a similar oxygen coordination, structural Fe2+ is more active in the decomposition of perborate than Fe3+. Exchanged Fe3+ ions of zeolites exhibit higher perborate decomposition capacity than structural Fe3+ or the Fe3+ of iron oxide.
Application of polarisation curves to the study of the electrochemical process for producing cuprous oxide
Authors: Vetere Vicente F. , Romagnoli Roberto
Published: July 2010

Polarisation curves are useful for establishing the optimum experimental conditions for producing electrolytic cuprous oxide. They provide a reasonable means of determining the influence of each variable on cuprous oxide formation at an electrode surface. In this work, a sodium chloride solution was electrolysed, and sodium hydroxide and sodium nitrate (in several concentrations) were added in successive stages to determine the behaviour of the resultant systems. Finally, the effect of the presence of cuprous oxide on the cathodic behaviour of the electrode was studied. The working electrode was of copper and the experiments were conducted at different temperatures. The polarisation curves were obtained without agitating the liquid and with aerated and deaerated solutions. The passage of nitrogen during 30 min removed oxygen from the electrolyte.
Ammonium nitrate formation in low concentration mixtures of oxides of nitrogen and ammonia
Authors: Mearns Alexander M. , Ofosu‐Asiedu Kingsley
Published: July 2010

The formation of ammonium nitrate in a reaction system containing oxides of nitrogen, ammonia, water vapour and oxygen present in ppm quantities in nitrogen was investigated. The measured amounts of nitrate produced were compared with those predicted by use of a kinetic model for the reacting system. For any temperature there was an initial pressure of ammonia below which nitrate was not found. This pressure was determined solely by thermodynamic considerations. At higher pressures of nitrogen dioxide, equilibrium was quickly attained, but at low pressures nitrate was not always formed in the time of contact of reactants. Water vapour enhanced the rate of formation of nitrate. The work has relevance to the possibility of formation of ammonium nitrate in nitric acid plants and to its formation in the atmosphere.
Solvolysis of 5‐bromovanillin to syringaldehyde in the presence of copper as catalyst
Authors: Borgaonkar Hemant V. , Chandalia Sampatraj B.
Published: July 2010

Solvolysis of substituted aromatic bromo‐aldehydes such as 5‐bromovanillin and 3,5‐dibromo‐4‐hydroxybenzaldehyde using anhydrous methanolic sodium methoxide was undertaken to produce syringaldehyde, which upon methylation with dimethyl sulphate gives 3,4,5‐trimethoxybenzaldehyde. The latter is an intermediate in the synthesis of trimethoprim, a well known antibacterial drug. The solvolysis was carried out in an agitated autoclave at 120°C, using dimethylformamide as a co‐solvent and metallic copper powder as catalyst. The effects of various parameters such as temperature, period of reaction, speed of agitation, type and loading of catalyst, addition of small amounts of water and concentration of co‐solvent on the conversion to syringaldehyde were examined.
Role of chromia in copper catalysts for dehydrogenation of ethanol
Authors: Prasad Y. S. , Padaliax B. D. , Raman S. K.
Published: July 2010

During direct vapour phase dehydrogenation of ethanol, a copper‐on‐silica catalyst lost much of its activity in 100 h. Analysis with X‐ray diffraction, scanning electron microscopy and X‐ray photoemission showed that both sintering and carbon deposition accompanied the drop in activity. In catalysts in which chromia was also present copper was found to be in a more highly dispersed form which was more resistant to sintering. The chromia catalyst accumulated carbon comparably to those containing copper only.
A potentiometric titration and electrophoresis study of the iso‐electric points and the points of zero charge of alumina coatings on rutile
Authors: Cornell Rochelle M. , Posner Alan M. , Quirk James P.
Published: July 2010

The iso‐electric points (i.e.p.) and the points of zero charge (p.z.c.) of alumina coated rutile pigments have been determined using potentiometric titrations and electrophoresis techniques. The alumina coated rutiles all had a p.z.c. close to pH9. The i.e.p. of coatings precipitated in an alkaline medium were close to pH7, while those of coatings precipitated in acid media were around pH5. The discrepancy between the values of the i.e.p. and the p.z.c. is thought to have arisen because the electrophoresis technique measures only the charge on the outer alumina coating, while the i.e.p. (found by titration) is a combination of charge properties of both the alumina and the underlying rutile (i.e.p. 3.7). It is suggested that the pigments whose coatings were precipitated in an alkaline medium have the higher i.e.p. because the alumina shields the rutile more effectively than does alumina that was precipitated in acid media.
Competitive hydrogenation of olefinic substrates on a Pt/SiO2 catalyst
Authors: Červený Libor , Mojžíšová Jana , Rr̊žička Vlastimil
Published: July 2010

The effect of structure of substrates and solvents on the process of competitive hydrogenation of binary mixtures of olefinic substrates in the liquid state on 5% Pt/SiO2 catalyst has been investigated. The hydrogenations were carried out at 20°C under atmospheric pressure of hydrogen in the absence of solvent, in methanol and in cyclohexane; one series was also performed in sec‐butanol and in tert‐butanol. Selectivity changed markedly owing to the different adsorptivity of the substrates. In more polar solvents hydrogenation of less polar substates was relatively preferred.
The clay mineral content of various rock types compared with the methylene blue value
Authors: Hills J. F. , Pettifer G. S.
Published: July 2010

The methylene blue test has been developed in France for giving an overall assessment of the clay characteristics of an aggregate. The Department of the Environment, Northern Ireland, introduced the test into a specification to indicate the soundness of basalt and gritstone aggregates—the test being carried out on finely ground samples. As the test was unfamiliar in the UK, it has been investigated. A detailed and expanded test‐method has been written and 28 samples, mainly from basic igneous rock sources, have been tested. Experiments have shown that the particle size of the test‐specimen affects the result (the ‘blue value’). The clay contents of the samples, and the swelling properties of the clay minerals, have been determined by X‐ray diffraction of the air‐dry and glycolated samples. Where the samples were of a suitable size, the water absorption has been measured. The correlations between the blue value and the following parameters are discussed: the clay content; the swelling properties; and the water absorption. It is concluded that the methylene blue test, carried out on a powdered sample, should not be used by itself to judge whether a source of aggregate should be accepted or rejected.
The methylene blue dye adsorption test in relation to aggregate drying shrinkage
Authors: Hosking J. R. , Pike D. C.
Published: July 2010

The Digest 35 method is commonly used in specifications to identify aggregates that are likely to produce concrete with high drying‐shrinkage characteristics. However this test is protracted and monopolises equipment for long periods of time. Studies of two variants of a methylene blue dye adsorption test are described. The main findings were: (1) The methylene blue dye adsorption test is simple, inexpensive and rapid. Such a test could provide a screening procedure that would reduce the number of Digest 35 tests needed. (2) With the exception of limestone aggregates, good correlation was found between the results of the dye and the Digest 35 tests. (3) The variant using small single‐sized samples gave the higher adsorption values and yielded a better separation. Using large real‐sized samples gave lower and less well‐separated results; however sampling error would be less and there would be some saving in time. (4) Care would be needed in the specification of a standard dye test because results were found to be sensitive to changes in test conditions.
Pyrolysis of black liquor
Authors: Bhattacharya P. K. , Shrinath A. S. , Kunzru D.
Published: July 2010

Concentrated black liquor was pyrolysed in a semi‐batch reactor in an inert atmosphere of nitrogen at 873–993 K. The effects of temperature and reaction time on the gas yields and compositions were studied. The main components of the gaseous product were hydrogen, methane, carbon monoxide, carbon dioxide and sulphur‐containing gases. The percentage recovery of energy was also determined. On the basis of the experimental runs, a reaction model was proposed for the kinetics of the pyrolysis reaction, and the activation energies and frequency factors of the rate constants were determined.
Polyethyleneglycol catalytic dehydration kinetics in the liquid phase
Authors: Simarro Ruben , Cervera S.
Published: July 2010

Eleven representative polyethyleneglycol (25322–68–3) catalytic dehydration reactions have been studied in the liquid phase at atmospheric pressure. The aim of this research is to build a kinetic model representative of the polyethyleneglycol dehydration process. Three types of reaction take place simultaneously in the process: cyclisation, condensation and alcoholysis. Activation energies and frequency factors are given, and the relationships between kinetic parameters and chain length of reactants and products are discussed according to the reaction type.
The formation of deposits from oil under conditions pertinent to diesel engine pistons
Authors: Alizadeh A. , Trimm D. L.
Published: July 2010

The production of deposits from oil on various materials has been studied under conditions pertinent to the ring zone of a diesel engine piston. Deposition is found to occur only as a result of oxidation, and metal catalysed free radical reactions in the liquid phase appear to be responsible for the problem. Metal species removed from the surface are the most active promoters and these may be deactivated by heavy deposition (encapsulation) or by the addition of deactivating complexing agents.
Effects of slag content, fineness and additive to cement pastes on the corrosion behaviour of embedded reinforcing steel
Authors: El‐Sayed H. A. , Shater M. A.
Published: July 2010

Previous studies proved that the slag content of the blast furnace slag‐Portland cement mix could be increased, while retaining the engineering properties of the produced slag cement pastes within the normal range and increasing the fineness of the mix. The corrosion behaviour of reinforcing steel embedded in the cement pastes giving the optimum mechanical properties was studied using the galvanostatic polarisation technique. The most corrosion‐resistant mix has been determined. The effect of adding CaCl2 to a paste of this mix on the corrosion behaviour of embedded reinforcing steel has been investigated. For the purpose of comparison, anodic polarisation tests were carried out using pastes having the composition of the most corrosion‐resistant mix but at the Blaine area of the ordinary slag cement. Portland and normal slag cements were also tested. The threshold concentration of CaCl2, below which breakdown of steel passivity did not occur, has been determined. The results of this study might have practical implications in the field.