The ionization of sulfurous acid in Na−Mg−Cl solutions at 25°C

The stoichiometric pK ₁ ^* and pK ₂ ^* for the ionization of sulfurous acid has been determined from emf measurements in NaCl solutions with varying concentrations of added MgCl₂ (m=0.1, 0.2 and 0.3) from I=0.5 to 6.0 molal at 25°C. These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interaction of Mg²⁺ with SO₂ and HSO ₃ ^– yielded =0.085±0.004, ⁽⁰⁾ = 0.35±0.02, ⁽¹⁾ = 1.2±0.04, and C = –0.072±0.007. The Pitzer parameters ⁽⁰) = –2.8±0.4, ⁽¹⁾ = 12.9±2.9 and ⁽²⁾ = –2071±57 have been determined for the interactions of Mg²⁺ with SO ₃ ^2– . The calculated values of pK ₁ ^* and pK ₂ ^* using Pitzer's equations reproduce the measured values to within ±0.04 pK units. The ion pairing model with log K_MgSO3=2.36±0.02 and log_MgSO3 = 0.1021, reproduces the experimental values of pK ₂ ^* to ±0.01. These results demonstrate that treating the data by considering the formation of MgSO₃ yields a better fit of the experimental measurements with fewer adjustable parameters. With these derived coefficients obtained from the Pitzer equations and the ion pairing model, it is possible to make reliable estimates of the activity coefficients of HSO ₃ ^– and SO ₃ ^2– in seawater, brines and marine aerosols containing Mg²⁺ ions.     

2-芳基硫杂脯氨酸结构特征的研究

对12种2-芳基硫杂脯氨酸进行了红外光谱和核磁共振谱测定,对其中两个化合物作了质谱测定。结果表明,这类化合物固态时主要以两性离子形式存在;有较强的分子离子峰,是一类较稳定的化合物。它们还存在一对非对映异构体,芳环上的取代基对芳环电子云密度的影响较大,而对四氢噻唑环的影响较小。     

Importance of the Debye interaction in organic solutions: Henry's law constants for polar liquids in nonpolar solvents and vice versa

Henry's law constants have been determined for -butyrolactone (BL), ethyl acetate (EA), and 2-methyl-3-pentanol (MEP) in mixtures of iso-octane (ISO) and toluene (TOL), for BL, EA, TOL, and ISO in cinnamaldehyde (CIN) and for TOL and ISO in each other and in BL. From these data and published vapor pressures, the activity coefficients at infinite dilution and the standard molar Gibbs free energy of transfer, G ₂ ⁰ of the solutes from dilute solution in ISO to dilute solution in each solvent medium have been calculated. The different behavior patterns of BL and EA are attributed to differences in their abilities to exist in different conformations possessing different dipole moments. For polar solutes, G ₂ ⁰ decreases with increasing polarizability of the solvent and with increasing dipole moment of the solute, suggesting increased contributions from dipole-induced dipole (Debye) interactions. The sigmoidal plot of G ₂ ⁰ against the change in pair potential energy calculated from the classical expressions suggests that G ₂ ⁰ seriously underestimates the strength of the Debye interactions in comparison with the London interactions.     

Liquid chromatography of the s-triazines

Summary A series of thirty s-triazine compounds have been separated using reversed-phase high-pressure liquid chromatography. A relationship between substituent activity and retention time was developed to predict molecular structure.Work partially completed at the CIBA-GEIGY Corp., McIntosh, Ala., USA.     

MgCl_2晶型对丙烯聚合MgCl_2载体催化剂活性的影响

ＭｇＣｌ_２晶型对丙烯聚合ＭｇＣｌ_２载体催化剂活性的影响张明辉，肖世镜中国科学院化学研究所，北京，１００８０）关键词丙烯聚合、ＭｇＣｌ２、载体催化剂近年来，有关ＭｇＣＩ。载体催化剂的研究报道和综述文章不少，但涉及载体晶型对催化剂结构性能的影响却少见．...     

4a,6,7,8a-Tetrahydro-1,3-dithiolo[4',5':5,6]-1,4-dithiino [2,3-b]-1,4-dithiine-2-thione as a precursor for synthesis of new organic π-donors

[2+4[-Cycloaddition of 2,3-dihydro-1,4-dithiine and oligomeric 1,3-dithiol-2,4,5-trithione results in the formation of 4a,6,7,8a-tetrahydro-1,3-dithiolo[4',5':5,61-[1,4[dithiino[2,3-b[1,4-dithiine-2-thione, which is a precursor for synthesis of new organic rz-donors.Translated fromIzvestiya Akademi Nauk Seriya Khimicheskaya No. 3, pp. 775–776, March, 1996.     

Na2SeO3在Fe电极上还原和吸附机理

采用循环伏安法、恒电势电解法、恒电流阶跃法及交流阻抗法研究Na2SeO3提高锌锰合金电沉积电流效率的作用机理.证明在锌锰合金电沉积的条件下，Na2SeO3 阴极被还原为Se32－并吸附在阴极表面上，从而阻止了氢原子在阴极表面的吸附，因而减少了氢离子的阴极还原.拟定了Na2SeO3的反应和吸附机理，用交流阻抗法进一步证明了所拟机理的正确性.     

载体对Au-Pd双金属催化剂加氢脱硫性能的影响

研究了Al_2O_3,TiO_2-Al_2O_3等载体对Au-Pd双金属催化剂的噻吩加氢脱硫性能的影响,并运用XRD,TPD,BET,TPR等手段对Au-Pd双金属催化剂进行了表征.结果表明,Au-Pd/TiO_2-Al_2O_3催化剂有较好的噻吩加氢脱硫反应活性和稳定性,与Au-Pd/Al_2O_3催化剂相比,Au-Pd/TiO_2-Al_2O_3催化剂有较高的酸密度和酸强度、活性表面积、H_2及CO的吸附量.     

Y2O3 and MgO co-doped ceria based electrolytes

Electrolytes of Ce_1-x-y Y _x Mg _y O_2-0.5x-y were prepared with citrate method and were characterized by inductively coupled plasma-atomic emission spectrometry, energy dispersive spectrometry, powder X-ray diffraction, and impedance spectroscopy. The effect of composition on the structure, conductivity, and stability of the electrolytes were investigated. When 0≤x≤ about 0.2 and 0≤y≤ about 0.05, the electrolytes were all single phase materials of ceria-based solid solution. However, when y> about 0.05, the electrolytes became two-phase materials, Y³⁺ and Mg²⁺ co-doped ceria-based solid solution and free MgO. The sample with nominal composition of Ce_0.815Y_0.065Mg_0.12O_2-d showed ionic conductivity at 973 K close to or even a little higher than that of similarly prepared Ce_0.9Gd_0.1O_1.95, but had lower cost of raw materials and a little better stability in reducing atmosphere. The existing of free MgO improved the stability of the electrolytes in reducing atmosphere, but too much free MgO reduced the conductivity.