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1.
2.
Studies on Oxide Catalysts. XXIX. Spectroscopic and Catalytic Investigations on Ni2+-, Co2+-, Cr3+-, and Cu2+-exchanged Mordenites NiNaM, CoNaM, CrNaM und CuNaM (M = Mordenite) have been characterized by UV-VIS, EPR and i.r. spectroscopy and the results were compared with the catalytic activity and the activity-time-dependence in the cracking of n-octane and with the shape selectivity in the cracking of a n-octane and isooctane mixture. Water molecules acting as ligands of the exchanged cations are able to dissociate yielding Brönsted acidity. Brönsted sites may be regarded as catalytic active centers in the cracking reaction. Unreduced transition metal cations facilitate the “coking” of the mordenite. The unreduced chromium and cobalt cations for which a position within the main channel is expected, affect the diffusion of the branched paraffin molecule thus increasing shape selectivity. 相似文献
3.
By the use of TG—MS, the thermal dissociation of anhydrous CuSO4 and Al2(S04)3 was found to proceed according to the reactions: followed by the reactions: No SO3 was indicated in the dissociation of alunite. The sulfate ion appears to dissociate by at least two different mechanisms although the parameter which controls the mechanisms has not been elucidated. 相似文献
4.
Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A
two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum
distillation of the total oil. Step two was a medium pressure LC separation with an AgNO3 impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related
sesquiterpene alcohols (75% of the oil). 相似文献
5.
Reactions of AgCl, AgSO4, and Ag2CO3 in and with pressed KCl, KBr, and KI disks as well as those of unpressed mixtures were followed by TG and DSC. Except for Ag2CO3 and Ag2SO4 in KI, the curves obtained were readily interpreted in terms of eutectic melting, decomposition, and complex formation. 相似文献
6.
The d.s.c. curves of commercial samples of methaqualone—Qulude (U.S.A.), Qulude (Mexico), Sopar, Mandrax and Parest — are presented. Similar d.s.c. curves were found for Qulude (U.S.A.), Qulude (Mexico), and Mandrax, while Sopar and Parest exhibited different types of curves. New and old formulations of the Qulude (U.S.A.) brand could be differentiated by differences in the tablet filler and binder. Unfortunately, d.s.c. could not be used to determine the country of origin of the drug, although it was useful to characterize it. The technique can be used to identify samples of 0.15 mg or less. 相似文献
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8.
The thermal dissociation of the cupferron complexes with Cu(II), Ni, Co(II), Zn, Cd, Mn(II), Hg(II), Mg, Ca, Ba, Sr, Al, Fe(III). Ce(III), La, and Nd was studied by differential thermal analysis (DTA) and by pyrolysis into a mass spectrometer. The DTA curves consisted mainly of endothermic peaks although some contained exothermic peaks as well. The mass spectrometer showed that cupferron decomposes slightly above room temperature, giving off N2, NO, N2O, NH3 and H2O. A mechanism for the thermal dissociation of the coppcr(II) cupferrate is proposed. 相似文献
9.
The thermal decomposition of the 2-methyl-8-quinolinol (8-hydroxyquinaldine) chelates of scandium, thorium, uranium(VI), yttrium and the rare earth elements was studied on the thermobalance. It was found that the scandium and uraniurn(VI) chelates can lose the extra molecule of solvation by thermal decomposition. The thorium chelate was found to be the most stable of all the chelates studied. The temperature limits for the chelates and the minimum oxide level temperatures are given. 相似文献
10.
W.W. Wendlandt 《Thermochimica Acta》1977,21(2):291-294
A convenient AC electrical conductivity apparatus is described. The sample, which is in the form of a pressed disk, is placed between two platinum plates located in a small cylindrical furnace. A 1–10V, 100 Hz potential is applied to the sample and the resulting current, in μA, is recorded on an X-Y recorder as a function of temperature. An EC curve of the dehydration of BaCl2 - 2H2O to BaCl2 - H2O is presented to illustrate the operation of the apparatus. 相似文献