摘要:

AbstractThree commercial oils commonly used for the froth flotation of fine coal were fractionally distilled in a high‐efficiency laboratory column. When the individual fractions were tested for flotative power on Gresford and Bedlington fine coals, little variation was found, except that components boiling at temperatures below 180° or above 280° had less power than those in the middle range.Some 20 simple substituted monohydric phenols of known constitution were subjected to a similar evaluation. They fell into four groups of very different flotative power.Many physical properties of the fractions and of the phenols were measured. No correlation was found between flotation merit and boiling point, solubility, refractive index or dielectric constant of the reagent, or the surface tension and relative surface viscosity of its saturated solution in water. On the other hand, there was a strong indication that the degree of ionization is important, good frothers for coal having dissociation constants (Ka) less than 10−7and non‐frothers greater than that value as a rule. The power of the phenols in small amount to reduce or refine the size of bubbles created in water by passing air through a porous disc was also shown to be directly related to their flotatio

ISSN:0021-8871    

DOI:10.1002/jctb.5010030702

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractMethyl linoleate hydroperoxide produced by ultra‐violet‐light‐catalysed oxidation of methyl linoleate has been thermally decomposed in the presence of excess of methyl linoleate. By carrying out the decomposition in an inert atmosphere it has been possible to trace the true reaction‐products formed by the initial peroxide‐oxygen. New oxygenated non‐peroxidic forms of methyl linoleate, dimeric and trimeric compounds are produced. The dimers have been characterized as carboncarbon‐bonded methyl linoleate molecules, but the trimers are of more complex structure. From the relative proportions of oxygenated monomer and polymeric compounds a tentative mechanism to explain the formation of the reaction products has

ISSN:0021-8871    

DOI:10.1002/jctb.5010030703

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractA study of the glycerol determination by the potassium periodate method has been carried out with the object of developing a rapid and yet fairly exact analytical procedure. It has been found that the time of oxidation recommended in the existing methods can be substantially reduced without affecting the accuracy of the determination. Several other modifications of these methods are suggested. In particular, the use of potassium dimesoperiodate (dipotassium periodate) instead of the much less soluble metaperiodate (monopotassium periodate) makes it possible to increase the size of the glycerol sample and thus to achieve a greater reproducibility of results.

ISSN:0021-8871    

DOI:10.1002/jctb.5010030704

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

Abstract2: 6‐Bis‐4′‐hydroxybenzylphenol has been synthesized by isomerization of 2: 6‐bis‐4′‐hydroxybenzylidenecyclohexanone and by condensation of 4‐bromo‐2: 6‐bishydroxymethylphenol with phenol and subsequent reduction of the resulting bromobishydroxybenzylphenol with palladium and hydrogen. 4:4′‐Dihydroxy‐3:5:3′:5′‐tetra‐(2″‐hydroxy‐3″:5″‐dimethyldibenzyl)diphenylmethane, which constitutes the first example of a hexanuclear novolak in which two novolak chains are linked by a central methylene bridge, has been synthesized by condensation of 2:6‐bishydroxymethyl‐4‐bromophenol with 2:4‐xylenol, dehalogenation of the di(hydroxydimethylbenzyl)bromophenol with palladium and hydrogen and condensation of the resulting 2:6‐di‐(2′‐hydroxy‐3′:5′‐dimethylbenzyl)phenol with formaldehyde. The hexanuclear novolak showed a pronounced tendency to form adducts with aliphatic alcohols, recalling the curiously stable additive complex of the tetranuclearp‐cresol novolak and ethylene dichloride. Examination of theX‐ray diffraction of specimens of the solvent‐free hexanuclear novolak and its methanol adduct in the Frevel focusing camera used in the earlier investigation2showed that, as with the tetranuclear compound and its ethylene dichloride adduct, the l

ISSN:0021-8871    

DOI:10.1002/jctb.5010030705

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractCalculations from published figures of the equilibrium constants for the decomposition 2HNO3H2O + 2NO2+ 1/2O2show that the degree of dissociation of nitric acid vapour is quite considerable even at moderate temperatures and reaches 100% at 200° and 1 atmosphere pressure. The rate of dissociation has been studied in glass cells at various temperatures (150–250°), by measuring the concentration of nitric acid through the amount of absorption observed in the 1·4‐μ region of the infra‐red. The significance of the results is discussed qual

ISSN:0021-8871    

DOI:10.1002/jctb.5010030706

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractThe action of some inhibitors on the autoxidation rates of aqueous stannous solutions has been studied. Two complex organic amino‐compounds, Bandrowski's base and Barsilowski's compound, were found to exert a powerful inhibitory effect on the oxidation of stannous chloride, thus confirming that the reaction involves a chain mechanism. Iron salts were found to have a similar effect on stannous acetate; this shows that the autoxidation likewise involves a chain proces

ISSN:0021-8871    

DOI:10.1002/jctb.5010030707

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractA rapid method has been devised for the determination of free formaldehyde in phenol‐formaldehyde syrups.The neutralized alcoholic solution of the sample is treated with hydroxylamine hydrochloride solution and the liberated hydrochloric acid then titrated with standard alkali to pH 3·4 by means of a direct‐reading pH m

ISSN:0021-8871    

DOI:10.1002/jctb.5010030708

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractThe variation of the viscosity with temperature has been studied on sols of an isoelectric ossein gelatin, and representation of this variation has been found possible by means of an equation of the type ν =AeK/T.The termAhas been shown to be a function of the percentage (weight) concentration of gelatin in the sol.A working hypothesis has been made that the hydration of the gelatin particles, during soaking, persists on dispersion; the decrease in viscosity with rising temperature is represented as due, in the main, to a progressive loss of the absorbed water back to the free dispersion medium, thereby decreasing the ratio of weight of dispersed phase to weight of dispersion medium.Expression of the viscosity as a function of this ratio had yielded an equation representing the variation of the viscosity with concentration of gelatin.The reversibility of the viscosity‐temperature variation has been explained as being due to the rupture and subsequent re‐formation of hydrogen bonds set up between the water molecules and the lyophilic peptide groups in the gelatin parti

ISSN:0021-8871    

DOI:10.1002/jctb.5010030709

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

ISSN:0021-8871    

DOI:10.1002/jctb.5010030710

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY

摘要:

AbstractCation‐exchange resins, prepared by sulphonating the polymers obtained from commercial cashew‐nut‐shell liquid and bhilawan‐shell liquid either by polymerization in the presence of sulphuric acid as catalyst or by condensation with formaldehyde, with caustic soda as catalyst, have relatively high capacity and contain all the three types of ionogenic groups—sulphonic, carboxyl and

ISSN:0021-8871    

DOI:10.1002/jctb.5010030711

出版商:John Wiley&Sons, Ltd    

年代:1953

数据来源: WILEY