摘要:

AbstractThe preparation of methacrylate esters by transesterification with ion‐exchange resins as acidic catalysts and n‐butanol as the reactant alcohol is described. Conventional cellular cation exchangers have been used together with a resin having a solid centre and a reactive outer surface. The latter resin is of lower capacity but the reaction rate compares favourably with that of conventional resins while its performance on repeated use is vastly super

ISSN:0021-8871    

DOI:10.1002/jctb.5010200401

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractPhysical characteristics of the hydrocarbon fermentation broth obtained during the microbial synthesis of protein concentrates from mineral oil have been studied. The effect of pH and the action of electrolytes and various organic compounds on the stability of the emulsion were investigated. It has been possible to obtain a fairly stable emulsion containing more than 85% of oil in the internal phase by the use of dry yeast cells. The strong hydrophilic character of the yeast cell membrane and the lowering of interfacial tension between the mineral oil and water are responsible for the unique stability.

ISSN:0021-8871    

DOI:10.1002/jctb.5010200402

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe solubilities of hydrogen halides (HCl, HBr, HI), expressed asxHXmoles of HX per mole of a liquid compound, have been determined for a representative selection of compounds at room temperature and below to reveal an essential pattern of behaviour to serve as a guide in operational procedures. Compared with the values predicted by Raoult's law at 0° (xHCl= 0.04,xHBr= 0.09,xHI= 0.37), liquids such as n‐heptane and carbon tetrachloride have slightly lowerxvalues, but show increasing divergence on the low side as the temperature is lowered. Other liquids, such as toluene and alkyl halides, have values greater than those predicted by Raoult's law at 0°, andxHXremains correspondingly higher at the lower temperatures. ThexHXvalues for many liquids can be from 2 to 6 times as great as those for water:xHCl= 0.41,xHBr= 0.49,xHI= 0.39 at 0°.From a consideration of pressure and other effects, a reference pattern of the constitution of the solutions is given. For the non‐aqueous liquids,xHXvalues greater than Raoult's law values are deemed to be the result of definite chemical reactions involving hydrogen bonding and dynamic equilibria. A case is presented for the desirability of the readjustment of attitudes towards acid‐base function in operational c

ISSN:0021-8871    

DOI:10.1002/jctb.5010200403

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractMeasurements of chemically combined water contents were made on Portland cement pastes made with water/cement ratios of 0.20 to 0.30 by weight. In addition to the factors involving water/cement ratio, curing medium, curing history and curing period, the degree of hydration of cement pastes cured at room temperature was significantly influenced by the availability of adequate water supply during the first 24 hours of the curing process.

ISSN:0021-8871    

DOI:10.1002/jctb.5010200404

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe kinetics of calcination of calcium sulphate dihydrate were studied at 100° at air pressures from 760 to less than 10−5mm Hg. Any reduction in air pressure below atmospheric caused an increase in reaction rate. Water vapour removal initially facilitated the dehydration at higher pressures, but began to impede the reaction at low pressur

ISSN:0021-8871    

DOI:10.1002/jctb.5010200405

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe settling of kaolin has been studied in various alcohol‐benzene mixtures, under controlled moisture conditions. The influence of the parameters of the settling apparatus has been evaluated. From the logQ/ϵ2vs. ϵ plots, the average particle size has been calculated, and the effect of absorbed moisture and the nature of the solvent mixture on cluster formation have been discussed. The constants of Oliver's equation for these systems have been obtained and their significance in the light of Landel's theory has been discus

ISSN:0021-8871    

DOI:10.1002/jctb.5010200406

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractFractions of road tars of coke‐oven and vertical retort origin were examined by high‐resolution mass spectrometry before and after exposure to road conditions. Molecular formulae and relative concentrations were determined for eleven series of peaks. A progressive increase in the proportion of components of high molecular weight (>mass 200) was indicated with exposure to road conditions. In the high molecular‐weight range, the heterocyclic structures containing oxygen showed larger increases than the polynuclear aromatic hydroca

ISSN:0021-8871    

DOI:10.1002/jctb.5010200407

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe thermal decomposition and vaporisation of ammonium sulphate, (NH4)2SO4, is shown to take place via two distinct sets of reactions. In the first, ammonium pyrosulphate, (NH4)2S2O7, is the primary condensed phase product: 2(NH4)2SO4← (NH4)2S2O7+2NH3+H2OThe second stage concerns the decomposition of the pyrosulphate. Ammonia, sulphur dioxide, nitrogen and water are the major products, the dominant reaction being 3(NH4)2S2O7← 2NH3+6SO2+2N2+

ISSN:0021-8871    

DOI:10.1002/jctb.5010200408

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY

摘要:

AbstractThe demand for graphites with specific properties and for an improvement in the economics of graphite production in recent years has led to an increased interest in catalytic graphitisation. At the present time, however, there is no review available of published studies and this paper attempts to make good this deficiency. Mechanisms whereby inorganic additives can catalyse graphitisation are considered, followed by a discussion of the mechanisms by which inorganic additives promote the graphitisation process. A comprehensive survey of the relevant literature to date is presented which describes in more detail the type of carbon used, the experimental techniques employed and the improvement obtained in graphite quality.

ISSN:0021-8871    

DOI:10.1002/jctb.5010200409

出版商:John Wiley&Sons, Ltd    

年代:1970

数据来源: WILEY