摘要:

AbstractA method has been developed for the examination of rates of reaction of a strongly basic ion‐exchange resin with a large organic anion.The results indicate that an organically fouled resin reacts at a slower rate than an unfouled one under standard conditions, and the possibilities of using the method as an aid to solving the problem of organic fouling are discusse

ISSN:0375-9210    

DOI:10.1002/jctb.5020210101

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA new method is described whereby the specific surface of colorants, i.e. pigments or insoluble or water‐soluble dyes, in cellulose can be measured. The principle of the method is the selective adsorption of p‐nitrophenol (PNP) from water by the colorant particles but not by the cellulose, thus permitting determination of the surface of the particles and the effect thereon of various treatments.Results with organic pigments in spun‐dyed viscose rayon agree with calculations of specific surface from particle‐size analysis of the pigments before incorporation. This shows that the whole surface of the colorants in the cellulose is accessible to PNP and thus measurements can be made with a variety of dyes.Azoic dyes and vat dyes give results that correspond to average particle diameters of ∼ 0.1–0.6 μm and the method detects the increase in their particle size on soaping.A direct cotton dye of low light fastness and a reactive dye give specific surface values much too low for a monolayer and they appear to exist as multilayers in cellulose. A direct cotton dye of high light fastness appears to be present as three‐dimensional aggregates of diameter ∼ 0.08 μm, in agreement with published electron micrograph values

ISSN:0375-9210    

DOI:10.1002/jctb.5020210102

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA comparison of odour with i.r. bands for 13 compounds showed an association between ‘green’ character and the position of the bands, especially the pattern A°CD, where A is 215–234, C 275–294 and D 300–319 cm−1and B denotes the absence of the band B 250–269 cm−1. However, this correlation gives only a rough evaluation. Of 12 compounds selected on a spectroscopic basis as having the ABCD pattern, 6 were found to have the expect

ISSN:0375-9210    

DOI:10.1002/jctb.5020210103

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractEstimates have been made of the production and use of the various materials used as road aggregates for 1966–67, and the regional distribution was also calculated. Future demand for road aggregates is considered, and it is estimated that the total demand by 1977 will be ∼ 85 × 106 tonnes per annum, the overall growth rate until then being ∼ 6% compound per

ISSN:0375-9210    

DOI:10.1002/jctb.5020210104

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe rate of dissolution of synthetic cupric sulphide (CuS) which is the analogue of the naturally occurring sulphide mineral covellite, in sulphuric acid solutions of concentration range 5 × 10−3to 3 mole/l over the temperature range 20–65°c at atmospheric pressure was studied.Thermodynamic considerations suggested that the primary reaction taking place during the leaching is: CuS+1/2O2+ H2SO4→ CuSO4+ S+H2O.It is proposed that up to an initial sulphuric acid concentration of 1 mole/l, the reaction rate is controlled by the diffusion of H+ions through the sulphur film to the CuS/S interface. For higher sulphuric acid concentrations the oxygen dissolved in the acid decreases and the rate‐determining step is believed to be diffusion of dissolved oxygen through the sulphur film to the CuS/S interface. A parabolic model is suggested for the dissolution reaction, and this model is supported by the experimental data.The activation energy for the dissolution reaction was found to be 8000±2000 cal/mole and this was independent of the H+concentration and hence the nature of the diffusi

ISSN:0375-9210    

DOI:10.1002/jctb.5020210105

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe responses of chromite and the gangue minerals olivine and serpentine commonly associated with it to fluoride activation in soap and anine flotation were studied.Hydrofluoric acid was shown to have good selective properties in amine flotation of chromite that qualify it as a possible flotation reagent. It seems that hydrofluoric acid could be adsorbed strongly and preferentially on the chromite surface to give the extremely insoluble CrF2−ion that exhibits great affinity for the positively charged dodecylammonium ion, leading to the formation of water‐repellent coatings. On the other hand, hydrofluoric acid attacks the magnesium and ferrous sites on the surface of olivine and serpentine with the formation of soluble magnesium and ferrous fluorides. Hydrofluoric acid also attacks the silicon sites at pH<4 with the formation of fluosilicic acid, and therefore impedes the formation of collector‐coating on the surface of olivine and serpentine.In contrast, sodium fluosilicate had a detrimental effect on both soap and amine flotation of chromite. This is probable due to its dissociation to SiF62−ions which are probably adsorbed on to cationic sites of chromite and gangue minerals with the formation of the corresponding negatively charged fluosilicates. As a consquence, dodecylammonium ions could be attached to the surface of chromite and gangue minerals, whereas oleate ions could not and hence the selectivity is completely de

ISSN:0375-9210    

DOI:10.1002/jctb.5020210106

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe vaporisation of sulphamic acid, NH2SO3H, at temperatures between 600 K and 740 K has been studied. The chemical constitution of the acid changes on melting in a manner which may be described by the equation: 12NH2SO3H→6NH4HSO4+ (NHSO2)6.SO3/H2SO4is released thereafter by the hydrolysis of the hexasulphimide (NHSO2)6. the requisite H2O being derived mainly from the decomposition of the NH4HSO4.SO3/H2SO4release is virtually complete by the time the acid has lost 20% of its original weight. During further vaporisation, SO2is the only vapour‐phase sulphur‐containing species to be released in significant quantities, the unevaporated residue comprising mainly of a 2:2:1 molar mixture of (NH4)2SO4, NH4HSO4and NH2(SO2NH)2SO2NH2.The use of sulphamic acid as a conditioner for the fly ash found in the flue gases of coal‐fired boiler plant is di

ISSN:0375-9210    

DOI:10.1002/jctb.5020210107

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractA variety of disruption techniques were used on brewers' yeast with subsequent estimation of the additional (assay‐increment) α‐glucosidase and invertase made accessible to p‐nitrophenylglucoside (PNPG) and sucrose, respectively, in the total disruptate. The extent of actual solubilisation of these two enzymes in the 0.75 M potassium phosphate buffer (pH 6.5) present, was also measured.Extensive release (i.e. solubilisation) of α‐glucosidase was achieved using ultrasonication or ethyl acetate autolysis, and here differential release of α‐glucosidase over invertase was large. Extensive release of both α‐glucosidase and invertase was obtained with snail gut enzyme and toluene (papain) autolysis, while air drying released some invertase but destroyed 80% of the α‐glucosidase.The assay‐increment, over intact yeast values, for α‐glucosidase in total disruptate, which is due to increased accessibility of PNPG to this enzyme, was high for salt autolysis and toluene (papain) autolysis but was low for the Mickle shaker and the Potter‐Elvehjem homogeniser. No increment was observed using the X‐press, although solubilisation of α‐glucosidase was moderately good.Increment, over intact yeast values, for invertase assay in total disruptate was highest with ultra‐sonication and air drying, but was nevertheless generally low owing to almost complete availability of this cell wall enzyme for assay—but

ISSN:0375-9210    

DOI:10.1002/jctb.5020210108

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY