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71.
Koji Yoshida Nobutaka Yamamoto Shinya Hosokawa Alfred Q.R. Baron Toshio Yamaguchi 《Chemical physics letters》2007,440(4-6):210-214
Inelastic X-ray scattering experiments have been performed on methanol as a function of density from ambient to the supercritical state. Positive dispersion of the sound velocity, as compared to the hydrodynamic values, is 50% in the ambient condition and decreases to zero at 0.50 g cm−3 over the momentum transfer Q = 1–10 nm−1 with lowering density; however, it increases again with a further decrease in density down to 0.20 g cm−3in the supercritical state only in the Q-range above 5 nm−1. These results have been interpreted as the formation of small oligomers in the low-density supercritical methanol. 相似文献
72.
Alfred Vendl 《Monatshefte für Chemie / Chemical Monthly》1979,110(3):685-691
The system V–Mo–N has been investigated at 1,100°C and nitrogen pressures between 1 and 300 bar by X-ray techniques. The isotypic compounds VN and Mo2N are forming a complete series of solid solutions at nitrogen pressures>30 bar. At a nitrogen pressure of 1 bar about 10% of the V-atoms can be replaced by Mo-atoms in the MN1-x
-compounds. Within the M2N-phase V-atoms can be replaced by Mo-atoms in the range of 10%. 相似文献
73.
Zusammenfassung Zur Bestimmung von phosphoriger und von unterphosphoriger Säure in Bädern zur stromlosen Herstellung von Metallüberzügen werden zwei neue Methoden beschrieben.Unterphosphorige Säure wird mit Silberperchlorat oxydiert und der Überschuß an Silberionen mit Natriumchlorid zurücktitriert. Die Summe von phosphoriger Säure und unterphosphoriger Säure wird bromatometrisch in 0,11 N salzsaurer Lösung bestimmt. Zur Erfassung der phosphorigen Säure eignet sich das von Norkus, Lunjackas u. Carankute beschriebene jodometrische Verfahren.
1 Diplomarbeit, Bergakademie Freiberg 1967. 相似文献
Summary Two new methods are described for the determination of phosphorous and hypophosphorous acid in bath solutions for the production of metal coatings without current. Hypophosphorous acid is oxidized with silver perchlorate and the excess of silver ions is back-titrated with sodium chloride. The sum of phosphorous and hypophosphorous acid is determined bromatometrically in 0.11 N hydrochloric acid solution. Phosphorous acid can be determined by the iodometric procedure according to Norkus, Lunjackas and Carankute.
1 Diplomarbeit, Bergakademie Freiberg 1967. 相似文献
74.
The equilibrium structures, binding energies, and vibrational spectra of the clusters CH3F(HF)1 n 3 and CH2F2(HF)1 n 3 have been investigated with the aid of large-scale ab initio calculations performed at the Møller–Plesset second-order level. In all complexes, a strong C–FH–F halogen–hydrogen bond is formed. For the cases n = 2 and n = 3, blue-shifting C–HF–H hydrogen bonds are formed additionally. Blue shifts are, however, encountered for all C–H stretching vibrations of the fluoromethanes in all complexes, whether they take part in a hydrogen bond or not, in particular also for n = 1. For the case n = 3, blue shifts of the ν(C–H) stretching vibrational modes larger than 50 cm−1 are predicted. As with the previously treated case of CHF3(HF)1 n 3 complexes (A. Karpfen, E. S. Kryachko, J. Phys. Chem. A 107 (2003) 9724), the typical blue-shifting properties are to a large degree determined by the presence of a strong C–FH–F halogen–hydrogen bond. Therefore, the term blue-shifted appears more appropriate for this class of complexes. Stretching the C–F bond of a fluoromethane by forming a halogen–hydrogen bond causes a shortening of all C–H bonds. The shortening of the C–H bonds is proportional to the stretching of the C–F bond. 相似文献
75.
Alfred Courtin 《Helvetica chimica acta》1983,66(1):68-75
Syntheses of Sulfonated Derivatives of 2-Fluoroaniline Synthesis of 4-amino-3-fluorobenzenesulfonic acid ( 3 ) was achieved in two ways: reaction of 2-fluoroaniline ( 1 ) with amidosulfonic acid and by first conventionally converting 4-nitro-3-fluoroaniline ( 8 ) to 4-nitro-3-fluorobenzenesulfonyl chloride ( 9 ) followed subsequently by hydrolysis to 3-fluoro-4-nitrobenzenesulfonic acid ( 10 ) and reduction. Hydrogenolysis of 3 gave sulfanilic acid ( 7 ). Both, sulfonation of fluorobenzene ( 6 ) to 4-fluorobenzenesulfonic acid ( 11 ) followed by nitration and sulfonation of 1-fluoro-2-nitrobenzene ( 12 ) led to 4-fluoro-3-nitrobenzenesulfonic acid ( 13 ). Reduction of 13 gave the isomeric 3-amino-4-fluorobenzenesulfonic acid ( 4 ), which was also obtained both by sulfonation of 1 and by sulfonation of o-fluoroacetanilide ( 14 ) followed by hydrolysis. Selective hydrogenolyses of 2-amino-5-bromo-3-fluorobenzenesulfonic acid ( 15 ), prepared by reaction of 4-bromo-2-fluoroaniline ( 16 ) with amidosulfonic acid, and of 4-amino-2-bromo-5-fluorobenzenesulfonic acid ( 20 ), obtained by sulfonation of 5-bromo-2-fluoroaniline ( 19 ) yielded the isomers 2-amino-3-fluorobenzenesulfonic acid ( 5 ) and 3 , respectively. The fourth isomer, 3-amino-2-fluorobenzenesulfonic acid ( 2 ), was synthesized by sulfur dioxide treatment of the diazonium chloride derived from 2-fluoro-3-nitroaniline ( 21 ) to 2-fluoro-3-nitrobenzenesulfonyl chloride ( 22 ), followed by hydrolysis to 2-fluoro-3-nitrobenzenesulfonic acid ( 23 ) and final Béchamp-reduction. 相似文献
76.
Gaetano Riggio Wolfgang Herbert Hopff Alfred Andr Hofmann Peter Gaudenz Waser 《Helvetica chimica acta》1983,66(4):1039-1045
Hydroxyphenyl-1-methylpyridinium-iodide as Potential Reactivators of Acetylcholinesterase Poisoned with Organophosphorus Compounds . It was our aim to reactivate acetylcholinesterase poisoned with sarin. We synthesized 2-(o-hydroxyphenyl)-1-methylpyridinium-iodide ( 9 ), 2-(p-hydroxyphenyl)-1-methylpyridinium-iodide ( 19 ) and 4-(o-hydroxyphenyl)-1-methylpyridinium-iodide ( 14 ) as potential reactivators. All substances showed moderate toxicity against mice; their reactivity potency in vitro and in vivo was negligible. 相似文献
77.
On the Synthesis of Sulfonated Derivatives of 2,3-Dimethylaniline and 3,4-Dimethylaniline Baking the hydrogensulfate salt of 2,3-dimethylaniline ( 1 ) or of 3,4-dimethylaniline ( 2 ) led to 4-amino-2,3-dimethylbenzenesulfonic acid ( 4 ) and 2-amino-4,5-dimethylbenzenesulfonic acid ( 5 ), respectively (Scheme 1). The sulfonic acid 5 was also obtained by treatment of 2 with sulfuric acid or by reaction of 2 with amidosulfuric acid. 3-Amino-4,5-dimethylbenzenesulfonic acid ( 3 ) and 5-Amino-2,3-dimethylbenzenesulfonic acid ( 6 ) were prepared by sulfonation of 1,2-dimethyl-3-nitrobenzene ( 9 ) to 3,4-dimethyl-5-nitrobenzenesulfonic acid ( 11 ) and of 1,2-dimethyl-4-nitrobenzene ( 10 ) to 2,3-dimethyl-5-nitrobenzenesulfonic acid ( 12 ), respectively, with subsequent Béchamp reduction (Scheme 1). Preparations of 2-amino-3,4-dimethylbenzenesulfonic acid ( 7 ) and of 6-amino-2,3-dimethylbenzenesulfonic acid ( 8 ) were achieved by the sulfur dioxide treatment of the diazonium chlorides derived from 3,4-dimethyl-2-nitroaniline ( 24 ) and from 2,3-dimethyl-6-nitroaniline ( 31 ) to 3,4-dimethyl-2-nitrobenzenesulfonyl chloride ( 29 ) and 2,3-dimethyl-6-nitrobenzenesulfonyl chloride ( 32 ), respectively, followed by hydrolysis to 3,4-dimethyl-2-nitrobenzenesulfonic acid ( 30 ) and 2,3-dimethyl-6-nitrobenzenesulfonic acid ( 33 ), and final reduction (Scheme 3). Compound 7 was also synthesized by reaction of 4-chloro-2,3-dimethylaniline ( 23 ) with amidosulfuric acid to 2-amino-5-chloro-3,4-dimethylbenzenesulfonic acid ( 20 ) and subsequent hydrogenolysis (Scheme 2). 4′-Bromo-2′, 3′-dimethyl-acetanilide ( 13 ) and 4′-chloro-2′, 3′-dimethyl-acetanilide ( 14 ) on treatment with oleum yielded 5-acetylamino-2-bromo-3,4-dimethylbenzenesulfonic acid ( 17 ) and 5-acetylamino-2-chloro-3,4-dimethylbenzenesulfonic acid ( 18 ), respectively. Their structures were proven by hydrolysis to 5-amino-2-bromo-3,4-dimethylbenzenesulfonic acid ( 21 ) and 5-amino-2-chloro-3,4-dimethylbenzenesulfonic acid ( 22 ), followed by reductive dehalogenation to 3 . 相似文献
78.
Mild Alkaline Hydrolysis of Aconitine Hydrolysis of aconitine ( 1 ) with 0.04N K2CO3 in 90% MeOH at room temperature yields, besides the alkamine aconine 3 considerable amounts of 8-O-methylaconine ( 6 ) and smaller quantities of desbenzoyl-pyroaconitine ( 4 ) and 16-epi-desbenzoyl-pyroaconitine ( 5 ). Better yields of 4 and 5 are obtained when heating a solution of aconitine in 0.04N K2CO3 in 90% EtOH. 相似文献
79.
Alfred Courtin 《Helvetica chimica acta》1981,64(2):572-578
Notes on the Synthesis of Sulfonated Derivatives of 5,6,7,8-Tetrahydro-1-naphthylamine and 5,6,7,8-Tetrahydro-2-naphthylamine Sulfonation of 5,6,7,8-tetrahydro-1-naphthylamine ( 1 ) with sulfuric acid gave a mixture of 1-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 2 ), 4-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 13 ) and 4-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid ( 3 ). The same reaction with 5,6,7,8-tetrahydro-2-naphthylamine ( 20 ) yielded 3-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 21 ); formation of 2-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid ( 16 ) or of 3-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid ( 24 ) was not observed. Treatment of 4-bromo-5,6,7,8-tetrahydro-1-naphthylamine ( 4 ) or of its 4-chloro analogue 5 with amidosulfuric acid gave 1-amino-4-bromo-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 9 ) and its 4-chloro analogue 10 , respectively, which were dehalogenated to 2 . Preparations of 13 and 24 were achieved by sulfonation of 5-nitro-1,2,3,4-tetrahydronaphthalene ( 14 ) and 6-nitro-1,2,3,4-tetrahydronaphthalene ( 22 ) to 4-nitro-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 15 ) and 3-nitro-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid ( 23 ), respectively, followed by Béchamp reductions. The sulfonic acid 13 was also obtained by hydrogenolysis of 4-amino-1-bromo-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid ( 11 ) or of its 1-chloro analogue 12 ; compounds 11 and 12 were synthesized from N-(4-bromo-5,6,7,8-tetrahydro-1-naphthyl)acetamide ( 7 ) and from its 4-chloro analogue 8 , respectively, by sulfonation with oleum and subsequent hydrolysis. By ‘baking’ the hydrogensulfate salt of 1 or 20 compounds 3 and 21 were obtained, respectively. Synthesis of 16 was achieved by sulfur dioxide treatment of the diazonium chloride derived from 2-nitro-5,6,7,8-tetrahydro-1-naphthylamine ( 17 ) giving 2-nitro-5,6,7,8-tetrahydronaphthalene-1-sulfonyl chloride ( 18 ), followed by hydrolysis of 18 to the corresponding sulfonic acid 19 and final reduction. 相似文献
80.
Köhler K Förster G Hauser A Dobner B Heiser UF Ziethe F Richter W Steiniger F Drechsler M Stettin H Blume A 《Journal of the American Chemical Society》2004,126(51):16804-16813
The temperature-dependent self-assembly of the single-chain bolaamphiphile dotriacontan-1,1'-diyl-bis[2-(trimethylammonio)ethyl phosphate] (PC-C32-PC) was investigated by transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray scattering, rheological measurements, and dynamic light scattering (DLS). At room temperature this compound, in which two phosphocholine headgroups are connected by a C(32) alkyl chain, proved to be capable of gelling water very efficiently by forming a dense network of nanofibers (Kohler et al. Angew. Chem., Int. Ed. 2004, 43, 245). A specific feature of this self-assembly process is that it is not driven by hydrogen bonds but solely by hydrophobic interactions of the long alkyl chains. The nanofibers have a thickness of roughly the molecular length and show a helical superstructure. A model for the molecular structure of the fibrils which considers the extreme constitution of the bolaamphiphile is proposed. Upon heating the suspensions three different phase transitions can be detected. Above 49 degrees C, the temperature of the main transition where the alkyl chains become "fluid", a clear low-viscosity solution is obtained due to a breakdown of the fibrils into smaller aggregates. Through mechanical stress the gel structure can be destroyed as well, indicating a low stability of these fibers. The gel formation is reversible, but as a drastic rearrangement of the molecules takes place, metastable states occur. 相似文献