碱金属氯化物-盐酸-水体系25℃溶解度预测

文献中未见MCl-HCl-H₂O(M=Li、Na、K、Rb、Cs)三元体系25℃时在HCl全浓度范围内溶解度预测的报道。本文报道应用Pitzer的离子相互作用模型,系统地对0.1～16.0 mol·kg^-1浓度范围内HCl的活度系数和渗透系数值进行最小二乘法拟合,得到一套优于文献上报道的作用参数。用这一套参数和本文报道中五个三元体系得到的θ_mn和φ_mnx,对溶解度预测获得满意结果。本方法可以推广到其它任何温度时、甚至相关四元和五元体系的溶解度预测,可以减少繁琐的实验测定,并对于利用HCl从盐卤中盐析分离LiCl、RbCl和CsCl的相化学工艺计算具有实际意义。     

Pitzer混合参数对HCl-KCl-H20体系25℃时溶解度预测的影响

The solubility variation of the phase system HC1-KC1-H2O at 25 C is reported when θHk(interactions between two species with the same charge) and ψmcl(interactions among three species)are changed within±10%. The calculated results indicate that the interactions among the three species are much stronger than that between the two species, whereas the combination of the two kinds of interactions result in great changes of the solubility of the system. This results is important for the salting out technology of the water-salt system.     

硫酸钍-硫酸铈-水体系的溶解度图(25℃)

研究硫酸钍-硫酸铈-水体系在25°时的溶解度图。体系中的二条溶解曲线相交于双饱和点, 其组成为:Th(SO_4)_2,4.23％(重量);Ce_2(SO_4)_3,9.52％(重量)。当溶液中硫酸铈浓度增加时,硫酸钍的溶解度自1.82％增至4.23％。当硫酸钍的浓度增加时,硫酸铈的溶解度也自7.62％增加至9.52％。     

Pitzer混合参数对HCl-KCl-H2O体系25 ℃时溶解度预测的影响

Pitzer混合参数对HCl-KCl-H2O体系25 ℃时溶解度预测的影响     

三元水盐体系25℃溶解度的预测——Pitzer电解质溶液理论应用之一

水盐体系溶解平衡的研究,无论在理论上还是在应用上都具有重要意义。多年来由于电解质溶液理论尚不够成熟,这种研究多半是进行大量的实验测定。尤其对于多组份体系更是如此。近年来,有些人开始以某些经验性的溶液理论尝试处理这种平衡关系。例如A.Lerman曾以Har-     

30℃时碳酸铯-乙醇-水三元体系的平衡溶解度

采用自制微型平衡溶解度装置, 首次研究了Cs2CO3-C2H5OH-H2O三元体系中出现醇相、水相和固相的三相平衡, 测定了碳酸铯在醇、纯水和混合溶剂中的溶解度, 并采用物化分析对数据进行处理, 结果表明, 碳酸铯对乙醇具有较强的盐析作用, 用"湿渣结线法"获得30 ℃时平衡固相的组成为Cs2CO3.3.5H2O.     

温和条件下稀土氯化物-萘催化的碱金属氢化物的合成

本文研究了稀土氯化物对碱金属氢化反应的催化作用.金属钠在稀土氯化物LnCl_3(Ln=La,Nd,Sm,Dy,Yb)和萘的催化下,在常压、40℃下能与氢气反应,生成氢化钠;稀土氯化物的催化活性顺序为LaCl_3>NdCl_3>SmCl_3>DyCl_3>YbCl_3.金属锂可发生类似反应,生成LiH;但其反应动力学曲线与金属钠相比明显不同.稀土氯化物对金属钾的氢化反应不显示催化作用.对反应机理的初步探索表明:碱金属与萘反应生成的阴离子自由基型物种可能是氢化反应的中间体,稀土氯化物的作用是催化该中间体的氢化反应.该反应的产物是一类大比表面积(NaH的比表面积为83m~2/g)、多孔性固体粉末,在空气中可自燃.它们具有比一般市售碱金属氢化物高得多的反应活性,并能与过渡金属配合物组成高活性烯烃加氢催化剂.     

温和条件下稀土氯化物-萘催化的碱金属氢化物的合成

本文研究了稀土氯化物对碱金属氢化反应的催化作用。金属钠在稀土氯化物LnCl~3(Ln=La,Nd,Sm,Dy,Yb)和萘的催化下,在常压、40℃下能与氢气反应,生成氢化钠;稀土氯化物的催化活性顺序为LaCl~3>NdCl~3>SmCl~3>DyCl~3>YbCl~3。金属锂可发生类似反应,生成LiH;但其反应动力学曲线与金属钠相比明显不同。稀土氯化物对金属钾的氢化反应不显示催化作用。对反应机理的初步探索表明:碱金属与萘反应生成的阴离子自由基型物种可能是氢化反应的中间体,稀土氯化物的作用是催化该中间体的氢化反应。该反应的产物是一类大比表面积(NaH的比表面积为83m^2/g)、多孔性固体粉末,在空气中可自燃。它们具有比一般市售碱金属氢化物高得多的反应活性,并能与过渡金属配合物组成高活性烯烃加氢催化。     

水溶液中盐酸-醇相互作用的热力学参数I. 盐酸-1, 2-丙二醇- 水体系(278.15 ～318.15K)

本工作在278.15～318.15K(间隔10K)下,测定了无液接电池Pt,H~2(g,p^0)|HCl(m~E)|AgCl-Ag;Pt,H~2(g,p^0)|HCl(m~E),PG(m~N)|AgCl-Ag的电动势,其中PG为1,2-丙二醇,m~E=0.005-0.1mol.kg^-^1,m~N=0.4-1mol.kg^-^1。实验数据用来计算HCl-PG-H~2O体系的盐效应常数k~s及HCl-PG的对相互作用的热力学参数f~E~N(g~E~N,s~E~N,h~E~N和c~P~,~E~N)。结果表明k~s>0,g~E~N>0,s~E~N>0,h~E~N>0,c~P~,~E~N<0。应用结构相互作用模型解释了这些参数的符号及其随温度变化的规律。     

THE QUENCHING OF TYROSINE AND TRYPTOPHAN FLUORESCENCE BY H2O AND D2O*

Abstract— The quantum yields and lifetimes of the fluorescence of tyrosine and tryptophan were determined in D₂O-H₂O and glycerol-H₂O solvent mixtures of varying composition from 10 vol.% to 100% H₂O at 15°C. Forboth amino acids the ratio of the quantum yields in D₂O and H₂O (i.e., q_D/q_H) was smaller than the ratio of the corresponding lifetimes (_D/_H). For tyrosine the ratio of the quantum yields in glycerol and H₂O (q_G/q_H) was also smaller than the corresponding _G/_H ratio, but for tryptophan q_G/g_HG/_H. The proximity of the q vs. plots for tyrosine in the two solvent mixtures indicates that at 15°C neither D₂O nor glycerol, in the pure state or when diluted with H₂O, quench tyrosine significantly. However, H₂O quenches tyrosine by a dynamic process, which increases both the radiative and the nonradiative rate constant. The quenching action is attributed to a tyrosine-H₂O exciplex, whose formation is independent of bulk viscosity and dielectric constant. Unlike tyrosine, tryptophan is quenched weakly by D₂O by a static process at 15°C (i.e., involving no change in), but H₂O quenches tryptophan much more efficiently by a dynamic process, which involves the nonradiative rate constant, but not the radiative constant. These results are explained on the basis of electrostatic complexation of the ammonium group to the carbon atom adjacent to the ring nitrogen with a lifetime which is longer thanin D₂O but shorter thanin H₂O, with solvent reorientation possibly also being an important factor in the quenching. This explanation is consistent with the fact that concentrated (8 M) urea increases q andof aqueous tryptophan ? 15–20%, while guanidine hydrochloride (6.4 M) has the opposite effect, i.e., it decreases q and t of tryptophan ? 15–20%, and with the fact that neither 8 M urea nor 6.4 M guanidine hydrochloride affects any fluorescence parameter of tyrosine at all.     

The overtone spectra of H2O,D2O and mixtures of H2O in D2O ice

The overtones of the stretching vibration of OH and OD were measured in solid solutions of H₂O in D₂O over a wide range of concentration and temperatures. The observed frequencies and the overall shape of the spectra were related to excitations of single OH or OD bonds (bound excitations) and those involving neighboring OH bonds extending over the crystal (non-bound excitations). The observed large anharmonicity of the bound state is interpreted as due to a low lying barrier in the double minimum potential curve for the hydrogen motion.     

微量吸附量热法测定负载型固体碱催化剂 K2O／γ—Al2O3的表面碱性

以CO2作探针分子,采用微量吸附量热法测定负载型固体碱K2O/γ-Al2O3的表面碱性.试验结果表明,样品表现了很强的碱性,起始CO2微分吸附热为160kJ@mol-1,饱和CO2覆盖度为550μmol@g-1,碱性强于纯MgO.     

KINETIC STUDIES OF SELF-SENSITIZED PHOTOOXYGENATION IN H2O AND D2O OF A WATER-SOLUBLE RUBRENE DERIVATIVE

Abstract A continuous argon laser has been used to study the self-sensitized photooxidation of potassium rubrene-2,3,8,9-tetracarboxylate in oxygen-saturated H₂O and D₂O. An analysis of the data obtained in concentrated solutions leads to an unexpected high value of the ratio of ¹O₂ lifetimes in D₂O and H₂O, ^T d ₂o/^T h ₂o =17 ± 1. Results obtained in diluted aqueous solutions are interpreted in terms of a re-encounter of ¹O₂ and ground state substrate molecules generated in the same triplet—triplet annihilation act.     

Rb2CO3—C2H5OH—H2O三元体系在40℃的溶解度及其应用

铷和铯是稀有分散的成盐元素,以往研究工作甚少,近年来铷和铯及其化合物在高新技术中的应用正受到人们的关注^[1]。钾、铷和铯的化学性质十分相似,尤其是铷与铯的分离和纯化难度很大,从矿物、盐卤和地热水资源中分离提取铷和铯的过程中,通常很难获得纯度较高的产品,开展铷盐纯化技术的研究具有重要的实际意义。混合溶剂用于盐类的分离和纯化,一直受到重视。文献^[2]中仅报道了对碱金属碳酸盐－醇－水在20℃时两相的分层关系,没有研究过饱和状态下的三相关系。根据碳酸铯在30℃乙醇中的溶解度比碳酸铷大5倍以上,我们采用国产碳酸铷商品作为试验物料,在测定了40℃时Rb2CO3-C2H5OH-H2O三元体系平衡溶解度相关系的基础上,进行简单的纯化处理,使该产品纯度得到进一步提高。     

THE ABSOLUTE VALUE OF THE REACTION RATE CONSTANT OF BILIRUBIN WITH SINGLET OXYGEN IN D2O

Abstract— The chemical reaction rate constant of bilirubin with singlet oxygen in basic aqueous solution has been redetermined to be 3.5 × 10⁸ M^-1 s^-1 by a competitive technique using a 1,3-diphenylisobenzofuran in sodium dodecyl sulfate micelles. Bilirubin also physically quenches a singlet oxygen with a rate constant of 9 × 10⁸ M ^-1 s^-1. The lifetime of singlet oxygen in D₂O solution has been determined to be 35 μ s . The absorption cross-section for the molecular oxygen ³∑_g-→¹δ _g + 1 v electronic transition at 1.06μn in aqueous solution is unexpectedly larger than the gas paase cross-section.     

Radioluminescence of H2O and D2O ice spectral characteristics

The spectra of the radiofluorescence RF, afterglow AG and the thermoluminescence TL of H₂O and D₂O ice are reported. The RF spectrum of D₂O exhibits two bands, whereas for H₂O only one of these is seen. The spectrum of TL is different from that of RF and AG. It is argued that if any of these spectra are due to de-excitation of the triplet state of water it is that of the TL. This spectrum is peaked at 335 ± 3 nm and has a width of 46 nm.     

PVTx measurements for N2O + CH3F, N2O + CH2F2, and N2O + CHF3 binary systems

Isochoric PVTx measurements have been performed for the binary system of nitrous oxide + CH₃F (R41), +CH₂F₂ (R32), and +CHF₃ (R23) using a new experimental set-up. The experiments covered both the two-phase region and the superheated vapor region and were performed within the temperature range 214–358 K and within a pressure range from 270 to 5600 kPa. Data have been collected for not less than four compositions for each system. The vapor–liquid equilibrium data were derived correlating the experimental data by means of the Carnahan–Starling–De Santis equation of state. The studied systems show a positive deviation from the Raoult's law. The results obtained were compared with the Burnett PVTx data. The two methods showed a mutual consistency within an acceptable margin of error. No other experimental PVTx data were found in the literature for these binary systems.     

K2O助剂对合成碳酸二甲酯用Cu—Ni／MoO3—SiO2催化剂吸附和反应性能的影响

用等体积浸渍法制备了MoO3-SiO2(MoSiO)表面复合氧化物负载的Cu-Ni-K2O催化剂。利用IR,TPR,TPD以及微反技术研究了K2O助剂对CO2和CH3OH在Cu-Ni/MoSiO催化剂表面上吸附和合成DMC（碳酸二甲酯）反应性能的影响。结果表明：K2O助剂的加入,使CO2在催化剂表面吸附强度增加,当K2O含量达Cu-Ni总量的15%时,CO2在催化剂表面上吸附后生成K2CO3;CH3OH在催化剂表面上的解离吸附态（CH3O^- H^ ）的吸附强度减弱;CO2和CH3OH和Cu-Ni-K2O/MoSiO催化剂表面反应主要产物为DMC,H2O,CO和CH2O。随着K2O助剂的加入,反应转化率在10%之前增加,之后下降,DMC选择性稍有提高。副产物（CO和CH2O）的选择性下降。根据实验结果探讨了K2O对催化剂表面活性中心的电荷分布的影响。     

Determination of ab initio force constants of F2O and H2O

Ab initio SCF calculations at the 4-31G level were performed to obtain the potential surface of the ground states of F₂O and H₂O. The 19-parameter quartic force field and the spectroscopic constants ω_i and x_ij were obtained.