摘要:

AbstractAlkylation of phenol with isobutene catalysed by Amberlyst 15 (cation exchange resin) was carried out in a batch reactor in the liquid phase. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size and stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a kinetic model based on homogeneous reaction. The apparent activation energies were found to be 57.7, 51.5 and 46.4 kJ mol‐1for the formations ofo‐alkylate,p‐alkylate and dialkylate respectively. The resin was found to have higher selectivity than the sulphuric acid cat

ISSN:0264-3413    

DOI:10.1002/jctb.504330102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe decomposition of dolomite was investigated in a bench‐scale fluidised bed reactor (30 cm diameter) at temperatures between 600°C and 1000°C in batch and continuous operations. The composition of the solids was determined by X‐ray analysis, the gas composition by infrared (i.r.) spectroscopic analysis. The reaction kinetics were investigated in a small fluidised bed (2.6 cm diameter) as well as in the bench‐scale equipment and compared with kinetic data evaluated from differential thermal gravimetric (DTG) curves. The measurements were carried out by adding small amounts of dolomite into the isothermal fluidised bed. The resulting CO2concentration within the gas could then be very low, thus MgCO3and CaCO3decompose as parallel reactions (singlestage reaction). At somewhat higher CO2gas concentrations prevailing in technical operational conditions the decomposition mechanism changes into a two‐stage reaction where MgCO3decomposes first. The bed temperature, pressure drop, superficial gas velocity, solid conversion, and specific interfacial area of solids were determined as functions of time and/or reactor wall temperature with a constant temperature increase rate for batch runs. The distributions of the residence time of solids indicate that in the continuously operated fluidised bed well‐mixed conditions prevail. The concentrations of dolomite, CaCO3, MgO, CaO, and solid conversion as well as the specific surface area of particles were determined as functions of the mean residence time in the continuous reactor. By means of the CO2concentration in the gas phase and the mean residence time the conversions of the consecutive reactions can be

ISSN:0264-3413    

DOI:10.1002/jctb.504330103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractFor possible antimicrobial activity, thiophene‐2‐sulphonyl chloride was condensed with primary or secondary amines, phenols and hydrazine hydrate. Thiopene‐2‐sulphonhydrazones and thiophene‐2‐sulphoniminoazo derivatives were obtained. The constitution of some of the prepared products is discussed in the light of their infrared spectra. The biological activities of all prepared compounds

ISSN:0264-3413    

DOI:10.1002/jctb.504330104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA full (25) factorial design at two levels has been used in the study of the separation of cobalt and nickel in sulphate solution, by solvent extraction with the sodium salt of di(2‐ethylhexyl) phosphoric acid. The variables selected for study were initial pH (4.0 and 5.5), initial aqueous cobalt concentration (10 and 25 g dm‐3), initial aqueous nickel concentration (20 and 50 g dm‐3), equilibrium temperature (50 and 80°C) and initial aqueous sodium sulphate concentration (0 and 0.5m) for an equilibration at fixed extractant concentration (0.5m) and fixed phase ratio (1:1). The responses studied were equilibrium organic cobalt concentration, equilibrium organic nickel concentration and equilibrium pH. The results may be explained in terms of the known chemistry of the system. All conclusions are restricted to the experimental range studied. Initial pH and initial sodium sulphate concentration have no effect on the separation. Separation is enhanced by increasing temperature, with a greater cobalt: nickel ratio in the organic phase. Empirical models which use first‐order polynomial expressions were found to represent the separation adequately at 80°C, while the detection of two‐factor interactions in the model including both temperatures indicates that second‐order polynomials will be required for satisfactory description.Predictions from the model for extraction at 80°C have compared quite favourably with equilibrium data obtained independently to the fa

ISSN:0264-3413    

DOI:10.1002/jctb.504330105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA thiazine photoelectrochemical cell has been developed involving thiazine photo‐reduction using EDTA as the electron donor together with photosynthetic electron transport in chloroplasts to generate electricity with a higher power conversion efficiency than for thiazine‐EDTA alone. Thionine and methylene blue have been shown to be electron acceptors of Photosystem I. The cell employed had a high ratio of the area of chloroplast‐impregnated membrane compared to the volume of thiazine solution. This emphasised the photosynthetic contribution. An open circuit photovoltage (Voc) of 415 mV, a maximum power density (Pa) of 4.15 m̈W cm‐2, a short circuit current density (Isc) of 50 m̈A cm‐2and a power conversion efficiency (Sp) of 0.145% were observed using thionine as the electron acceptor compared to aVocof 383 mV, aPdof 3.0 m̈W cm‐2, andIscof 43.0 m̈A cm‐2and anpof 0.095% when methylene blue was used as the electron acceptor. These results show that the thiazine photogalvanic cell can be combined with the chloroplast solar battery in order to increase the power conversion efficie

ISSN:0264-3413    

DOI:10.1002/jctb.504330106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of bismuth‐molybdenum catalyst on the vapour‐phase nitration of propanebutane fraction with nitric acid has been studied. The catalyst examined increases the total yield of nitroparaffins obtained nearly four times in comparison with the nitration without catalyst. The influence of the temperature, initial mole ratio of gas/nitric acid and contact time on the catalyst activity and the yields of individual nitroparaffins have been stud

ISSN:0264-3413    

DOI:10.1002/jctb.504330107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractAdsorption of Triton X‐100 on a reservoir sand (characterised by chemical analysis and i.r. spectra to be silica) has been studied under field conditions. The adsorption behaviour is best characterised by Freundlich and Temkin adsorption models. The kinetics of adsorption is found to be very much dependent on temperature and the rate of adsorption shows an anti‐Arrhenius temperature dependence. The adsorption is proposed to proceed through Si—CH3bond formation. Addition of common inorganic salts is found to cause maxima and minima in the adsorption isotherm and to change the shape of the iso

ISSN:0264-3413    

DOI:10.1002/jctb.504330108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe cure of a range of elastomeric building sealants is investigated by measuring tack‐free time and hardness under a range of laboratory test regimes and under natural exposure. Temperature, relative humidity and ultraviolet light were noted to have an interactive effect on cure, although the influence of these factors varied between the different sealant types studied. The investigation identifies laboratory conditions which are favourable to cure, and these are compared with cure conditions specified in standard test

ISSN:0264-3413    

DOI:10.1002/jctb.504330109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

ISSN:0264-3413    

DOI:10.1002/jctb.504330101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY