The Concentration Dependence of the Apparent Molal Adiabatic Compressibility of Electrolytes in WaterSakurai, Masao; Komatsu, Tsuyoshi; Nakagawa, Tsurutaro
doi: 10.1246/bcsj.54.643pmid: N/A
The apparent molal adiabatic compressibilities of NaCl, KCl, NaBr, and KBr in water have been measured in the concentration range from 0.01 to 1 mol kg−1 at 5, 25, and 45 °C. The results have been fitted to a Redlichtype equation: φKs=φKs°+SKsc1⁄2+BKsc. The limiting slope, SKs, was found experimentally as 5.6×10−4 at an ordinary temperature. Convenient equations for the conversion of adiabatic to isothermal compressibilities have been derived; the limiting slope for isothermal compressibility, SKT, should be larger than SKs at all the temperatures studied. The value of SKs determined experimentally has been compared with that predicted from the SKT values calculated by Mathieson and Conway, by Millero, and by Bradley and Pitzer.
A Solid-state Electrochemical Study on the Phenothiazine–Iodine and Related ComplexesMatsumoto, Toshiyuki; Matsunaga, Yoshio
doi: 10.1246/bcsj.54.648pmid: N/A
The electromotive force (emf) of a solid-state galvanic cell, Ag|AgI|PT–In, where PT–In is the phenothiazine-iodine complex, was examined as functions of the composition, n, and also of the temperature. Below n=2.5, a value of 616 mV was obtained at 25 °C. The emf increases stepwise to 620 mV at n=2.5 in conformity with the formation of a complex cation radical pentaiodide, as established by our earlier work. A continuous increase up to 649 mV was found before n=3, indicating the appearance of a nonstoichiometric phase covering the range from n=2.8 to 3. The upper limit of the existence region exactly corresponds with the minimum in the resistivity-composition isotherm. Similar studies with benzo[a]- and benzo[c]phenothiazines revealed the formation of three or four distinct nonstoichiometric complexes in each system. The Gibbs energy, enthalpy, and entropy of cell reactions and complex formation reactions are presented. The stability of the iodine complexes was found in the following order: benzo[a]phenothiazine>benzo[c]phenothiazine>phenothiazine.
The Activities of Sodium Salts of 1-Amino-4-alkylaminoanthraquinone-2-sulfonic Acid in Aqueous SolutionsMitsuishi, Masaru; Yamaguchi, Yuzoh
doi: 10.1246/bcsj.54.654pmid: N/A
The mean activity coefficients of sodium salts of 1-amino-4-alkylaminoanthraquinone-2-sulfonic acid (alk= Me(MAS), Et, n-Pr, or n-Bu (n-BAS)) in aqueous solutions ranging in concentration from 10−3 to 10−2 mol kg−1 have been determined by means of isopiestic measurements at 50 and 60 °C respectively. It has been found that the mean activity coefficients of these dyes are much smaller than unity, the coefficients of MAS being the largest, and those of n-BAS, the smallest. The coefficients have been found to decrease with an increase in the dye concentration. An examination of the results obtained by Miliceivic treatment suggests that the MAS exists as dimer or trimers, and the other dyes, as tetramers, at 60 °C.
The Crystal and Molecular Structure of Grayanotoxin XVIII. A New Minor Diterpene from Leucothoe Grayana Max.Furusaki, Akio; Gasa, Shinsei; Ikeda, Ry\={u}z\={o}; Matsumoto, Takeshi; Yasuoka, Noritake; Matsuura, Yoshiki
doi: 10.1246/bcsj.54.657pmid: N/A
The molecular structure of grayanotoxin XVIII C20H28O4, has been determined by means of X-ray crystal analysis. The crystals are monoclinic, with two molecules in a unit cell with dimensions of a=9.592, b=11.414, c=8.180 Å, and β=93.21°; the space group is P21. 1484 unique intensity data were collected on a four-circle diffractometer with Ni-filtered Cu Kα radiation. The structure was solved by the Monte Carlo direct method, using the 20 strongest reflections as the starting set; the 25th random-phase set led to the correct solution. The R value reached 4.6% by block-diagonal least-squares refinements. The structure thus obtained corresponds to 3-dehydrograyanotoxin VII. The C-ring takes a boat conformation. The force-field calculations suggest that this energy loss is probably compensated for by the stabilization of the B-ring conformation. The crystal consists of hydrogen-bonded molecular layers parallel to the (100) plane.
Electrode Kinetics of Eu(III) Ion in the Presence of 1,4-BenzenedimethanolIkeda, Osamu; Tsuura, Katsuhiko; Tamura, Hideo
doi: 10.1246/bcsj.54.661pmid: N/A
In order to know the role of aromatic ring on the electrode kinetics, d. c. polarogram of Eu(III) ion was measured in the presence of 1,4-benzenedimethanol (1,4-BDM). The effect of the adsorption has been discussed by correlating the kinetic data to the adsorption behaviors of 1,4-BDM estimated from the electrocapillary curves. At the standard potential of Eu(III)/Eu(II) (−0.600 V vs. SCE), 1.4-BDM on the electrode changed its orientation from horizontal to vertical with an increase in the coverage. Both orientations showed an inhibition effect for the electroreduction of Eu(III) ion. When the coverage due to the horizontal orientation is less than 0.8, the inhibition was interpreted by an additional energy to deform the surface layer. On the other hand, the inhibition at full coverage due to both the horizontal and the vertical orientations was interpreted by the tunneling probability through the adsorbed layer differed in the thickness.
On Behaviors of a New Chemical Reaction Model Showing Hard OscillationsIwamoto, Kazutoshi; Seno, Manabu
doi: 10.1246/bcsj.54.669pmid: N/A
The behavior of a new chemical reaction model was studied and the existence of hard oscillations was confirmed. This chemical reaction model is useful because it is easy to apply to investigations of the behavior of a chemically oscillating system surrounded by membranes or in a well-stirred continuous flow reactor. The latter was discussed relating to the chaotic oscillations due to the Belousov-Zhabotinskii reaction in a well-stirred continuous flow reactor reported by Schmitz et al.
Reaction of Metastable Ar Atoms with Propylene in Flow SystemSibata, Akiko; Takahasi, Makoto; Ohno, Shinichi; Mikuni, Hitoshi
doi: 10.1246/bcsj.54.678pmid: N/A
The reaction of metastable Ar atoms with propylene was studied in a discharge flow system. The major product is ethylene, although ethane, propane and butadiene are also identified as minor products. Within a limited range of propylene concentration the yield of ethylene is proportional to the concentration of propylene. Competitive quenching methods using mixtures of propylene and N2O or CO2 provided a rate constant of (8.4±0.3)×10−10 cm3 molecule−1 s−1 for the reaction of metastable Ar atom with propylene to yield ethylene. The assumption of a radical mechanism for the main reaction is consistent with the results of competitive quenching, radical scavenger and spin trapping experiments. Measurements of ion current in the reaction mixtures allow an estimation that ionic species contribute less than 2% to the reaction path leading to the formation of ethylene. The metastable Ar atom reaction was also compared to the direct and mercury-sensitized photolysis of propylene.
Pressure-induced Phase Transition and Compressive Behavior of Substituted AdamantanesHara, Kimihiko; Katou, Yoshikazu; Osugi, Jiro
doi: 10.1246/bcsj.54.687pmid: N/A
The compressive behavior of adamantane and its secondary monosubstituted derivatives; adamantanone, 2-methyladamantane, and 2-bromoadamantane was measured at various temperatures in a piston-cylinder apparatus. A first-order solid-solid phase transition was found under pressure in each system. The transition pressures, the equilibrium pressures, the volume changes, and the entropy changes for the transition were determined. The compression data for the low pressure phases were fitted to an equation of the form −ΔV⁄V0=a0+a1P+a2P2. The effects of substituent groups on the entropy changes of the transitions of these molecular crystals were discussed.