摘要:

AbstractImproved experimental details are reported for the preparation of 4‐amino‐2‐nitrophenylarsonic acid by the known five‐stage route fromp‐phenylenediamine in an overall yield

ISSN:0021-8871    

DOI:10.1002/jctb.5010011101

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractMeasurement of the optical transmission of a suspension of small particles is of considerable importance, e.g. for determination of particle size. In certain conditions interpretation of measurements is simple, i.e. when it may be assumed that the particles behave as an opaque screen of area equal to the total projected area of the particles in the beam. In general, however, the projected area must be multiplied by a factorK, known as the total scattering coefficient, which can have values between o and about 5.The present paper reviews the values ofKas a function of the wavelength λ of the incident light, the refractive index, absorption and radius (a) of the particles, and the angular size of the detector used in an experimental arrangement.Attention is confined to spherical particles. By using elementary diffraction theory it is possible to obtain a physical picture of the reasons for the variation ofKfrom the value I expected from geometrical optics. Exact methods of calculation are discussed, following Airy, Mie and Rayleigh for the respective cases a≫λ, a∽λ, a≪; some typical results from published calculations are quoted and reviewed, and optimum conditions for measurement are s

ISSN:0021-8871    

DOI:10.1002/jctb.5010011102

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractTo estimate the impurities in aluminium alloy a d.c. arc is used. An aluminium‐alloy rod, 12 mm. in diameter and faced up on the lathe, is employed as the positive electrode and a graphite rod pointed to 60° as the negative one. Analysed samples and suitable standards are spread over the photographic plate as in spark exposures. They are energized in an arc under defined conditions, i.e. 4‐mm. gap between the electrodes, potential difference 220 v., current 7 amp., etc. Ilford thin‐film half‐tone plates are used and are developed according to the maker's instructions. The spectra registered are then measured and evaluated in a similar manner to that used for the spark spectra; an internal comparison method is used. In arc spectra registered under these conditions the densities of the analysed samples are similar, and on this account the same standards may be used for all unknown samples which pass through the spectroscopic laboratory. This method properly used gives accurate and reproducible

ISSN:0021-8871    

DOI:10.1002/jctb.5010011103

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractDetails of the laboratory and semi‐technical‐scale preparation of acenapththylene by the vapour‐phase dehydrogenation of acenaphthene are given.Polymerization of acenaphthylene is discussed together with some of the properties of the plasticized polymer. Copolymers with styrene have been studied in their preparation by bulk, bead and emulsion processes and some of their properties have been related to composition and mode of polymerization. The availability and economics of the monomer are considered br

ISSN:0021-8871    

DOI:10.1002/jctb.5010011104

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractA simple laboratory device is described which allows the double distillation of water in a continuous and automatic way in order to produce particularly pure water. The water thus obtained has a mean specific conductivity of 0.5 × 10‐6ohm‐1cm.‐1at

ISSN:0021-8871    

DOI:10.1002/jctb.5010011105

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractMethods for the isolation of laminarin from the common brown algae indigenous to Great Britain have been worked out on the laboratory scale with a view to the ultimate development of a process suitable for large‐scale production. These methods comprise treating the fresh or dried milled weed with hydrochloric acid or sulphuric acid at pH 2·4 and isolating the laminarin from the acid extra

ISSN:0021-8871    

DOI:10.1002/jctb.5010011112

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractMany workers have described costly phenol‐formaldehyde or amine‐formaldehyde resins for ion‐exchange. Tannins of the catechol type can also be used for the same purpose. In a previously published communication (Bhatnagar&Singh, 1950), it has been shown that katha (the edible material used in betel leaves) yields on sulphonation products which exhibit calcium and magnesium exchange. More resins from katha and cutch have now been prepared and their adsorptive properties have been studied.The products obtained by sulphonation of katha and cutch and subsequent condensation with formalin are found to adsorb about 95% and 65% fatty acids respectively from centimolar solutions. The resins obtained by mere sulphonation show little adsorption of acids. The products obtained by direct condensation of katha and cutch with formalin exhibit 15% and 0% adsorption respectively of benzoic acid. On the other hand, resinous products obtained by incorporation of katha and cutch in phenolic resins prepared using ammonia as a catalyst show high adsorption values, namely, 55% and 70% respectively of formic acid. The adsorptive properties of standard resins, e.g. Amberlites, Zeo‐karbs, etc., have also been studied. The study reveals that the prepared resins are comparable with standard

ISSN:0021-8871    

DOI:10.1002/jctb.5010011106

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe adsorption of homologous series of monobasic and dibasic aliphatic acids by katha and cutch resins has been studied. The adsorption decreases with the increase in the molecular weight. This reversal of Traube's rule is explained on the basis of orientation of molecules at the resin‐water surface according to the theory of Langmuir and Harkins. The influence of substituted hydroxyl groups has also been studied. The adsorption of barium, strontium and calcium has been studied. The order of adsorption is explained on the basis of the polar concep

ISSN:0021-8871    

DOI:10.1002/jctb.5010011107

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe active agent in dilute aqueous detergent solutions can be extracted without loss withn‐butanol in presence of added sodium carbonat

ISSN:0021-8871    

DOI:10.1002/jctb.5010011108

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY

摘要:

AbstractThe preparation of I‐hydroxy‐2 : 6‐bis‐(2‐hydroxybenzyl)benzene by dehalogenation of the corresponding trichloro compound was described in Part X of this series (Finn, Lewis&Megson, 1950). The removal of the chlorine was effected by treatment of the boiling amyl alcohol solution of the compound with sodium. The yield was poor and amounted to only 5% of theory.It has now been found that the dehalogenation can be achieved more satisfactorily by treatment of a solution of the diphenylmethane derivative in aqueous sodium hydroxide with Raney nickel‐aluminium alloy. A yield of about 50% of theory is obtained.2 : 2′‐Dihydroxydiphenylmethane may be obtained from 2 : 2′‐dihydroxy‐5 : 5′‐dichloro‐diphenylmethane by the same means and the method has been used to prepare 2 : 2′‐dihydroxy‐3 : 5‐dimethyldiphenylmethane, 2 : 2′‐dihydroxy‐3 : 3′ : 5 : 5′‐tetramethyldiphenylmethane, and I‐hydroxy

ISSN:0021-8871    

DOI:10.1002/jctb.5010011109

出版商:John Wiley&Sons, Ltd    

年代:1951

数据来源: WILEY