Volumetric Properties of Ternary-Pseudobinary Mixtures Containing Benzene and Cyclohexane

Densities have been measured as a function of composition for ternary-pseudobinary mixtures of [(benzene + toluene or methylcyclohexane) + (cyclohexane + toluene or methylcyclohexane)] by means of a vibrating-tube densimeter at atmospheric pressure and the temperature 298.15 K. The excess molar volumes, V_m^E, were calculated from the densities and correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show the third component, toluene and methylcyclohexane, influences the interaction between benzene and cyclohexane.     

Separation of Benzene and Cyclohexane Using Eutectic Solvents with Aromatic Structure

The separation of benzene and cyclohexane is a challenging process in the petrochemical industry, mainly because of their close boiling points. Extractive separation of the benzene-cyclohexane mixture has been shown to be feasible, but it is important to find solvents with good extractive performance. In this work, 23 eutectic solvents (ESs) containing aromatic components were screened using the predictive COSMO-RS and their respective performance was compared with other solvents. The screening results were validated with experimental work in which the liquid–liquid equilibria of the three preselected ESs were studied with benzene and cyclohexane at 298.5 K and 101.325 kPa, with benzene concentrations in the feed ranging from 10 to 60 wt%. The performance of the ESs studied was compared with organic solvents, ionic liquids, and other ESs reported in the literature. This work demonstrates the potential for improved extractive separation of the benzene-cyclohexane mixture by using ESs with aromatic moieties.     

Effects of the Presence of Cyclohexane or Methylcyclohexane on the Densities and Volumetric Properties of the Mixture (Benzene + Propionitrile)

Excess molar volumes, V_m^E, have been obtained as a function of composition for ternary-pseudobinary mixtures of [(benzene + cyclohexane or methylcyclohexane) + (propionitrile + cyclohexane or methylcyclohexane)] from the densities measured by means of a vibrating-tube densimeter at atmospheric pressure and a temperature of 298.15 K. The values of V_m^E have been correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show that the third component, cyclohexane or methylcyclohexane, has a significant effect on the interaction between benzene and propionitrile.     

Behavior of Iodine in Binary Mixtures of Cyclohexane with Dioxane and Tetrahydrofuran Using a Multivariate Curve Resolution Technique

The electronic spectra of the iodine molecule in binary mixed solvent systems dioxane–cyclohexane and tetrahydrofuran–cyclohexane were subjected to the multivariate curve–resolution analysis. By using the singular value decomposition method, four different species were identified in the binary mixed solvents. The multivariate curve resolution–alternating least-squares (MCR–ALS) method of Tauler was used to extract the concentration profile and pure spectra of the species present in the mixed solvent systems. Evolving factor analysis was used to obtain the initial estimate of the concentration profiles of the components. The MCR-ALS was implemented by using selected constraints, such as, nonnegativity, unimodality, selectivity, and closure, which are applied during each iteration. Several MCR runs were performed by changing constraints to find the results with lowest fitting error and most chemically reasonable spectra and concentration profiles. From the resulting pure spectra for different iodine species and the corresponding concentration profiles, the nature of iodine species detected in the mixed solvent systems and the influence of the nature of cosolvent have been discussed.     

用超声波技术制备的Raney Ni催化剂及其催化加氢活性

 将超声波技术与碱抽滤方法相结合制备出一种Raney Ni催化剂. 以苯饱和加氢为探针反应,测定了超声处理时间对Raney Ni催化剂催化活性(包括吸氢速率和苯转化率)的影响. 结果表明,超声处理对催化剂的活性有明显的促进作用. 随着超声处理时间的延长,催化剂的活性先逐渐升高,后慢慢降低,超声处理15 min时可获得最高的催化活性. 通过ICP,XRD,XPS,BET和SEM等手段对Raney Ni催化剂的表面电子态、比表面积、孔体积、孔径、粒径及表面形貌等进行了表征,并对超声波的作用进行了初步讨论.     

Apparent Dipole Moments of 1-Butanol, 1-Propanol, and Chlorobenzene in Cyclohexane or Benzene, and Excess Molar Volumes of (1-Propanol or Chlorobenzene + Cyclohexane or Benzene) at T = 298.15K

Apparent dipole moments and relative permittivities of {x1-butanol + (1 – x) cyclohexane}, {x1-propanol + (1 – x)cyclohexane or (1 – x)benzene} and {xchloro- benzene + (1 – x)cyclohexane or (1 – x)benzene} were determined for the mole fraction range of 0.0003 < x < 0.1 at a temperature of T = 298.15 K and at a frequency of f = 100 kHz. The apparent dipole moments were calculated using Frohlich equation. The molar excess volumes for {x1-propanol + (1 – x)cyclohexane or (1 – x) benzene} and {xchlorobenzene + (1 – x)cyclohexane} were determined by a vibrating-tube densimeter at T = 298.15 K.     

自组装中的苯二甲酸阴离子形貌及质子化效应

在高效合成大环主体化合物环[2][2,6-二（1H-咪唑基）]吡啶[2]（1,4-二亚甲基苯）[cyclo[2]（2,6-bis（1H-imidazol-1-yl）pyridine）[2]（1,4-dimethylenebenzene）;1⁴⁺]的基础上,通过溶液中核磁¹H谱、扩散排序核磁共振谱（Diffusion Ordered NMR Spectroscopy;DOSY）、二维核磁欧沃豪斯效应增强谱（Nuclear Overhauser Effect Spectroscopy;NOESY）波谱方法,气相中质谱（ESI-MS）及固相中X射线单晶衍射方法,详细考察1⁴⁺与一系列苯二甲酸阴离子客体的相互作用. 发现苯二甲酸阴离子客体的形貌与质子化因素对主客体的作用模式、相互作用的化学计量比以及形成超分子自组装复合物的结合常数均起着决定性的作用. 本文结果将有助于指导后继新型大环主体化合物与多羧酸阴离子构筑的自组装体系的设计和研究.     

Pt/TiO2光催化降解苯的磁场效应研究

采用连续流动微分反应体系考察了外加磁场对Pt/TiO₂光催化降解苯反应性能的影响, 发现一定强度的外加磁场可提高气相光催化降解苯的反应活性. 结合瞬态光电导法和原位傅立叶变换红外技术研究了外加磁场对光生载流子寿命和反应中间体分布的影响, 结果表明, 外加磁场不仅延长了光生载流子的寿命, 而且提高了某些中间体的转化率, 从而改善了光催化降解反应的活性.     

Effect of Different Salts on the Solubilities of Benzene and Diphenyl in t—Butyl Alcohol—Water Mixture and Hydrophobic Interaction

The solubilities of benzene and diphenyl in mixed solvents of t-butyl alcohol (TBA) and water with different salts have been determined at T=298.15,303.15,308.15 and 313.15K.The molar fraction of TBA [x(TBA)] in mixed solvent is 0.045,and the molality of the salts (ms) in mixed solvents are 0.000,0.250,0.500,0.750 and 1.000mol/kg ,respectively.The standard Gibbs energies of solution of benzene and diphenyl in the mixed solvents have also been calculated based on the solubility data.The effects of different salts on the hydrophobic interaction (HI) for benzene-benzene pair in the systems were discussed.     

Liquid Solution Densities of Ternary-Pseudobinary Mixtures of (Benzene + Cyclohexane) in the Presence of Tetrachloromethane or <Emphasis Type="Italic">n</Emphasis>-Hexane

Densities have been obtained as a function of composition for ternary-pseudobinary mixtures of [(benzene + tetrachloromethane or n-hexane) + (cyclohexane + tetrachloromethane or n-hexane)] at atmospheric pressure and the temperature 298.15 K, by means of a vibrating-tube densimeter. Excess molar volumes, V_m^E, partial molar volumes and excess partial molar volumes were calculated from the density data. The values of V_m^E have been correlated using the Redlich–Kister equation and the coefficients and standard errors were estimated. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show that the third component, CCl₄ or n-C₆H₁₄, have quite different influences on the volumetric properties of binary liquid mixtures of benzene with cyclohexane.     

利用瞬态吸收光谱技术研究水体中苯与亚硝酸的交叉反应机理

利用瞬态吸收光谱技术进行了有氧、无氧条件下苯与亚硝酸水溶液复相体系的交叉反应机理研究 ,初步考察了这些瞬态物种的生长与衰减等行为 ;并对其光解产物进行了GC/MS分析 .研究表明 ,HNO2 在 3 5 5nm紫外光的照射下可产生·OH和NO+ ,·OH自由基和苯反应生成C6H6 OHadduct ,反应速率常数为 8 9× 10 9L·mol-1·s-1,在有氧条件下C6H6 OHadduct进一步氧化为C6H6 OHO2 ,反应速率常数 3 3× 10 8L·mol-1·s-1;NO+ 自由基和苯作用形成C6H6 NO+ πcomplex ,然后进一步分解     

A Look at the Spatial Confining Effect on the Molecular Electrostatic Potential (MEP)—A Case Study of the HF and BrCN Molecules

In this theoretical study, we report on the molecular electrostatic potential (MEP) of titled molecules confined by repulsive potentials of cylindrical symmetry mimicking a topology. Our calculations show that the spatial restriction significantly changes the picture of the MEP of molecules in a quantitative and qualitative sense. In particular, the drastic changes in the MEP as a function of the strength of spatial confinement are observed for the BrCN molecule. This preliminary study is the first step in the investigation of the behavior of the MEP of molecular systems under orbital compression.     

Dipole moments of Flourobenzene and its Mesogenic Derivative in 1,4-Dioxane and 1-Butanol Solutions

Experimental data from dielectric investigations of solutions of flourobenzene (FB) and its mesogenic derivative (1-fluoro-4-(4-pentylcyclohexyl) benzene (FPCHB) in 1,4-dioxane are reported for various mole fractions and temperatures. The molecular dipole moments were determined using the Guggenheim-Debye method in the temperature range of 298.2 to 318.2 K. Both fluorinated compounds show a positive and small temperature coefficient for the effective dipole moment. Variations of the effective dipole moment and correlation factor, g, with mole fraction in these mixtures were investigated using the Kirkwood-Frohlich equation. Dielectric measurements were also carried out on binary mixtures of FPCHB with 1-butanol for various concentrations at 318.2 K. The Kirkwood correlation factor, the Bruggeman factor, and the excess permittivity were determined.     

Temperature Dependences of the Kinetic Isotope Effect and the Ratio of the Reaction Rates for Reaction of Cyclopentane and Cyclohexane with HOCl in Water

We have determined the activation parameters logA and E for the Arrhenius equations for the kinetic isotope effect (c-C₆H₁₂/c-C₆D₁₂) and the 5/6 effect (c-C₅H₁₀/c-C₆H₁₂) in reactions of the C—H bonds of cycloalkanes with HOCl in aqueous solutions in the interval 30-90 °C. The data obtained are consistent with a chlorination mechanism including a pre-activation step with formation of an HO^· ... Cl^· pair, linear abstraction of the H atom by the OH group and angular attack by the Cl atom "at a distance" on the carbon atom.     

Dipole Moments and Intermolecular Association of Some Carbonyl Compounds in Nonpolar Solvents

The aggregation of some aldehydes in nonpolar solvents was investigated using the static dielectric method. The molecular association of acetone and two of its derivatives (acetophenone and benzophenone) in cyclohexane solvent were also investigated by this method. Analysis of the static dielectric data for solution of these materials indicated a high molecular association. It was found that benzaldehyde and its derivatives have a strong tendency for antiparallel molecular association, whereas acetone and its derivatives have a tendency for parallel alignment. The experimental results show that there is a sensitive relationship between the molecular association and molecular structure of these materials. The influence of solvent on the molecular association of the solute molecules was studied and compared.     

介质阻挡放电与 CuZSM-5 结合方式对脱除 NOx 的影响

 研究了介质阻挡放电 (DBD) 与 CuZSM-5 结合方式, 即 DBD 和 CuZSM-5 两段分置 (两段法) 或将 CuZSM-5 放入 DBD 区 (一段法), 对脱除氮氧化物的影响. 结果表明, 在 NO/N2 或 NO/C2H4/N2 无氧体系中, DBD 与 CuZSM-5 结合产生的协同效应很小; 在 NO/O2/N2 富氧体系中, DBD 与 CuZSM-5 结合导致氮氧化物转化率下降; 而在 NO/C2H4/O2 /N2 富氧体系中, 在 250 ºC, 空速 12 000 h1, 输入放电能量密度 (Ein) 155 J/L 的条件下, 单纯催化、单纯等离子体放电、一段法和两段法时氮氧化物转化率分别为 39%, 1.5%, 79% 和 52%. 两段法产生了中等程度的协同效应, 主要是第一段等离子体放电产生新稳态物种 (如 NO2, CO 和 CO2 等) 起作用; 而一段法产生的协同效应较大, 主要是由于等离子体放电产生的新稳态物种和激发态短寿命物种 (如 N2*, NO*, CH 和 CN 等) 共同起作用.     

Ion Association and Hydration in Aqueous Solutions of Nickel(II) and Cobalt(II) Sulfate

Aqueous solutions of nickel(II) and cobalt(II) sulfate have been investigated at 25 ^∘C by dielectric relaxation spectroscopy (DRS) over a wide range of frequencies (0.2 ≤ ν (GHz) ≤ 89) and salt concentrations (0.025 ≤ c(mol-L⁻¹) ≤ 1.4). The spectra indicate, as for MgSO₄(aq) studied previously, the simultaneous presence of double solvent-separated, solvent-shared and contact ion pairs in both NiSO₄(aq) and CoSO₄(aq). The stepwise formation constants for each ion-pair type and the overall association constant, obtained from the data are in good agreement with ultrasonic relaxation and other estimates. The DR spectra at higher concentrations (c ≥ 0.5 mol-L⁻¹) suggest the existence of a nonlinear triple ion M₂SO₄²⁺(aq). Consistent with the very strong hydration of the salts, which have ‘effective’ hydration numbers approaching 27 at infinite dilution, there are no significant differences in any of the relaxation or thermodynamic parameters for NiSO₄(aq) and CoSO₄(aq), except that the triple ion appears to be somewhat more stable for the latter.     

Molar and Partial Molar Excess Volumes of Benzene in Methyl Ester Solutions at 25°C

Molar and partial molar excess volumes of mixtures of benzene with several methyl esters (from methanoate to decanoate) were determined, over the whole concentration range, at 25°C and atmospheric pressure from experimental densities and correlated by a suitable equation. The applicability of the Flory and Priggogine–Flory–Pattersort models for predicting molar excess volumes is tested. The calculated values with Flory and Priggogine–Flory–Patterson are similar and agree poorly with the experimental data.     

Decomposition of Benzene in Air in a Plasma Reactor: Effect of Reactor Type and Operating Conditions

The decomposition of benzene was carried out in two types of plasma reactors packed with BaTiO₃ pellets: one reactor had two stainless steel electrodes (SUS reactor), and the other reactor had a glass layer between two concentric electrodes (GL reactor). The decomposition efficiency and the suppression of formation of N₂O and NO_x were greater in the GL reactor than in the SUS reactor. In contrast, the suppression of O₃ formation and the oxidation to CO_x in the SUS reactor were superior to those in the GL reactor. The effect of wa eform and frequency of applied ac power was in estigated for each reactor.