ISSN:0021-2148    

DOI:10.1002/ijch.197100059

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe crystal structures of 9‐methyl‐, 9‐methoxycarbonyl‐, and 9‐methoxyanthracene have been solved by the SEARCH procedure and refined from partial three‐dimensional photographic data to acceptable agreement factors. The molecular shapes are briefly discussed. The packing arrangements of the first two compounds provide for antiparallel juxtaposition across inversion centres of nearest‐neighbour molecules (interplanar distances of 3.57 and 3.39 Å) and C(9) … C(10′) contacts of 3.87 and 3.68 Å. In the non‐centrosymmetric packing of 9‐methoxyanthracene the distances betweenmeso‐carbons of nearest‐neighbour molec

ISSN:0021-2148    

DOI:10.1002/ijch.197100060

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe solid‐state photochemistry of several substituted anthracenes has been investigated with particular reference to the behaviour of polymorphic forms of the monomers. A class of 9‐substituted anthracenes (methyl, methoxycarbonyl, chloro, bromo) crystallising in anti‐parallel, sandwich packing arrangements give centrosymmetric dianthracenes in accordance with the topochemical principle, which also operates on light‐stable monomers packing in non‐centrosymmetric space groups having axes>8 Å (e. g. 9‐methoxy, 9‐ethoxy‐, 1‐cyano‐) and showing no short parallel interplanar contacts. Some but not all monomers, crystallising in the parallel‐stack type with a 4 Å axis, dimerise to the non‐topochemical head‐to‐tail dimer. Two monomers substituted elsewhere than in the 9‐position give the theoretical number of solution dimers but yield on

ISSN:0021-2148    

DOI:10.1002/ijch.197100061

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe balance of heat flow at the growth interface during Czochralski crystal pulling is discussed, taking into consideration the curvature of the interface. Mechanisms are postulated according to which sudden and slow changes in the pulling rate influence the growth process and detachment of the crystal from the melt. An expression is derived for the smallest diameter to which necking down can be carried out under stable growth conditions.

ISSN:0021-2148    

DOI:10.1002/ijch.197100062

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractAdsorption of HCl, DCl and Cl2on high surface area germanium films was studied by means of IR absorption spectra. The films were prepared by high temperature evaporation of germanium in a helium atmosphere. On adsorption of HCl and DCl two main absorptions appeared at 460 cm−1and 408 cm−1and additional weaker bands at 2050 cm−1and 2920 cm−1(with HCl) and at 1313 cm−1(with DCl). The spectra indicate that both gases undergo dissociation on adsorption. In the case of Cl2the bands at 460 cm−1and 408 cm−1appeared in the spectrum; here again strong evidence exists that dissociative adsorption takes place. Mass spectrometer analysis showed that the desorption product consists ma

ISSN:0021-2148    

DOI:10.1002/ijch.197100063

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe infrared and Raman spectra of normal and 89.5 atom %18O‐labelled sodium sulphate have been measured both for the solid salts and for their aqueous solutions. All the fundamentals of S16O2−4and S18O2−4have been observed. The observed isotopic frequency ratios of these fundamentals agree excellently with t

ISSN:0021-2148    

DOI:10.1002/ijch.197100064

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe preparation of bipolar membranes from a single sheet of polyolephine by sulphochlorination is described in detail. Rectification experiments between salt solutions and between HCl and NaOH solutions respectively are described. The transference of salt ions relative to each other and relative to the ions of water have been determined. Some analytical data on the concentration of mobile ions in the membranes during current transport are given. The mechanism of rectification is explained and used to clarify the experimental results. Problems concerning conduction in bipolar membranes are enumerated and some experiments are proposed which may assist in solving them.

ISSN:0021-2148    

DOI:10.1002/ijch.197100065

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe sorption of copper species from copper bromide and copper nitrate dissolved in a series of organic solvents onto the bromide form of an anion exchanger (Dowex 1 × 10) was studied. The species sorbed were identified and the products of exchange determined. A mechanism for the sorption from these solutions was suggested

ISSN:0021-2148    

DOI:10.1002/ijch.197100066

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractWhile 4 distinct endothermal processes are known to accompany the thermal decomposition of Ammonium Perchlorate (AP), the DTA thermograms show one endotherm corresponding to the structure transition at 240°C, and two exotherms. The different characteristic points of the DTA thermograms change with the thermal history of the sample and even with aging at ambient temperature. Periods of preheating at 150° lower the initial temperature of self‐heating at a later heating from about 300° for freshly recrystallised AP to about 210° after preheating for 4 days at 150°C. Heating‐cooling cycles above 200° (lower limit) up to 320° (upper limit) show for the first 2‐3 cycles the influence of the known “limited decomposition” of AP. On cooling there is a temperature delay in the structure transition cubic → orthorhombic, up to a constant limit of about 15°, and an apparent co

ISSN:0021-2148    

DOI:10.1002/ijch.197100067

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractThe mineralogy of refractory bricks (50% Al2O3) made under varying conditions of temperature, pressure and grain size was investigated. Maximum temperature attained was 1450°C, pressure was varied between hand pressing and 1000 kg/cm2, grain size ranged from<0.088 mm to 6 mm and was obtained by varying duration of the grinding process. The bricks produced were subjected to chemical and X‐ray diffraction studies, measurement of physical properties, and optical studies in thin sections. It is concluded that optimum conditions for manufacture of refractory brick are high temperature and pressure. Grain size itself is crucial, but the grinding process is far more efficient if the two starting clay materials are ground together rather than separately. It was concluded that TiO2served as a mineralizer, and it favors well developed mullite crystal. Cristobalite was not detected at all by optical methods, while it was detected clearly by X‐ray diffrac

ISSN:0021-2148    

DOI:10.1002/ijch.197100068

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY