ISSN:0021-8871    

DOI:10.1002/jctb.5010100114

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractMeasurements have been made of the physical properties of a series of pure n‐alkyl trifluoroacetates. The values of the bond parachors, bond refractions and bond refractivities for the (C‐F) link are compared with those derived previously for the n‐alkyl fluo

ISSN:0021-8871    

DOI:10.1002/jctb.5010100103

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractThe hydrothermal reactions in lime‐quartz pastes of varying lime/silica ratios have been studied at temperatures from 90 to 200° in periods not normally exceeding 5 days. The compounds present were identified byX‐ray powder photography. Reaction is seldom complete and mixtures of two or more hydrated calcium silicates are frequent. The use of different samples of lime and quartz gives differing results. A hitherto unreported compound, provisionally called phase F, of possible formula C5S3H2Cement chemical nomenclature will be employed where applicable; C=CaO, S=SiO2, H=H2O. However, the abbreviations CSH(I) and CSH(II) are used to mean ‘calcium silicate hydrate (I)’ and ‘calcium silicate hydrate (II)’, and do not imply monocalcium silicate monohydrate compositions.has been prepared at temperatures near 165°. Thermobalance runs have shown that synthetic xonotlite and tobermorite differ in water content from the naturally‐occu

ISSN:0021-8871    

DOI:10.1002/jctb.5010100104

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractA method is described for the determination of trace amounts of cyanide ion in water by linearsweep cathode ray polarography. The method is shown to be unaffected by the presence of large excesses of chloride, but free chlorine, bromine and iodine, as well as sulphide ion, must be absent. The limit of detection is about 0·05 μg. per m

ISSN:0021-8871    

DOI:10.1002/jctb.5010100105

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractPhorone, 2,6‐dimethyl‐2,5‐heptadien‐4‐one (I), when prepared by the dehydration of acetone condensation products with mineral acid catalysts, is accompanied by an isomer, purer samples of which were prepared by isomerisation of pure phorone with an acid catalyst and subsequent distillation; by this method scanty but definite evidence of a second isomer was obtained. The isomer obtained by dehydration is shown to be 2,6‐dimethyl‐1,5‐heptadiene‐4‐one (II) and the equilibrium mixture of phorone and isomer (II) at room temperature contains about 7% of isomer (II). Both phorone and isomer (II) can be rearranged to the equilibrium mixture by acid or alkali treatment but are reasonably stable, even to distillation at atmospheric pressure, under neutral conditions. The second isomer found in isomerisation experiments is believed, from spectroscopic and chemical evidence on its mixtures with isomer (II), to be 2,6‐dimethyl‐1,6‐heptadien‐4‐one (III).Attempts to prepare the 2,4‐dinitrophenylhydrazone of phorone yielded mixtures. The properties of purified derivatives of phorone, phorone isomer (II) an

ISSN:0021-8871    

DOI:10.1002/jctb.5010100106

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractEarlier work had suggested that the adsorption of sodium alkyl sulphates upon tin surfaces was instrumental in initiating corrosion. A compound of this class labelled with35S has now been used in a study of the adsorptive process.Adsorption was greater on rough surfaces than on smooth and increased with concentration. Solutions of 0·1 g.‐mole per litre were found to behave irregularly and to form multilayers, thus explaining the reduced corrosivity at this concentration. Desorption of sodium alkyl sulphate was found to be slow but almost complete, indicating little chemisorption on the tin surfa

ISSN:0021-8871    

DOI:10.1002/jctb.5010100107

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractThe relation between the petrology and polished‐stone coefficient of various natural roadstones, which have been polished in an accelerated‐wear machine at the Road Research Laboratory, is discussed. The mineralogy, the variation in hardness of the constituents, the texture and the amount of alteration all appear to be connected with the degree of polish which the rock acquires during the test. These factors variously affect the different roadstone gro

ISSN:0021-8871    

DOI:10.1002/jctb.5010100108

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractX‐Ray diffraction studies were carried out on the hydrated alumina precipitated during the seeded decomposition of sodium aluminate solution in the presence of glucose, cane sugar and starch (white potato), and the results are considered in relation to the rate of decomposition.Glucose and sugar suppress bayerite formation, may increase crystallite size, and slow down decomposition. Starch is without effect on bayerite formation and increases the rate and extent of decompositio

ISSN:0021-8871    

DOI:10.1002/jctb.5010100109

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractCalcium oxide samples differing widely in surface activity (5–100m.2g.‐1) have been ‘wet’ hydrated at room temperature using water, pure or diluted with acetone as an inert liquid.Rates of hydration and changes in surface area and lattice structure indicate that ‘wet’ hydration proceeds by a mechanism similar to that found earlier for ‘dry’ hydration by water vapour, i.e., hydration proceeds inwards from the outside of each calcium oxide particle by an advancing interface mechanism. In each case, the more active limes become aged (agglomerated) rapidly, but when the less active limes are ‘wet’ hydrated the number of crystallites generally increases much more than for ‘dry’ hydration; cleavage of the calcium hydroxide formed on the surface of the oxide is therefore more extensive, in keeping with the faster hydration. Slow ‘wet’ hydrations using 1% water more closely resemble ‘dry’ hydrations in that the number of crystallites increases only over their later stages. Ultimately, all the ‘wet’ hydrated samples age on prolonged contact with water, their crystallite growth showing some relationship to that of calcium hydroxide precipitated fr

ISSN:0021-8871    

DOI:10.1002/jctb.5010100110

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY

摘要:

AbstractSamples of calcium oxide and calcium hydroxide have been carbonatated under ‘dry’ conditions using carbon dioxide gas, and under ‘wet’ conditions using carbon dioxide dissolved in water or in alkaline media, viz., ammonium or sodium carbonates and bicarbonates. The progress of these carbonatations has been followed by determining changes in surface area and lattice structure, and the surface properties of the final products have been compared with those of calcium carbonate precipitated from solution at similar pH levels.In either ‘dry’ or ‘wet’ conditions, the carbonatation proceeds inwards from the outside of each particle by an advancing interface mechanism, being inhibited by the low porosity of the calcium carbonate layer normally developed around each particle. In ‘wet’ conditions, the growth and porosity of the calcium carbonate layer depends largely on the pH of the surrounding solution, since this determines the rate of formation and the solubility of the calcium carbonate. The tendency of the layer to age is related to the growth and ageing of calcium carbonate particles precipitated from solution by d

ISSN:0021-8871    

DOI:10.1002/jctb.5010100111

出版商:John Wiley&Sons, Ltd    

年代:1960

数据来源: WILEY