冶金过程多组分体系同时反应的动力学模型及应用

将钢铁冶金中的多组分同时反应作为一个综合的反应体系进行研究,考虑其中各反应间的影响. 根据冶金热力学和动力学原理建立多组分渣-金-气反应体系同时反应动力学模型,编制计算程序,得出成分对时间的变化曲线,并用含Fe-Cr-Mn-C的渣-金反应体系的实验进行了验证. 结果表明,金属液中C和Mn组分的计算浓度与实测值基本吻合,Cr的计算浓度与实测值的相对误差在9.1%以内. 在直流电弧下熔炼存在大气通过渣层向金属液的传氧现象,其数值与大气向钢液直接传氧的数值相同. 采用模型方法能较好地解释过程中的反应现象,揭示过程的机理.     

胶束催化作用及其在动力学分析中的应用

研究表明，适量的胶束可催化化学反应，在动力学分析中大有潜力，本文介绍了胶束催化作用，并就其在动力学分析中的最新研究进展及时予以评述。     

混合体系多组分同时测定中提高精度的残差研究

混合体系多组分同时测定中提高精度的残差研究李于善（宜昌教育学院４４３３００）非参数估计是一种具有重大实用价值的统计数学方法，比参数估计有更大的稳妥性与实用性。此数学方法由通（Ｔｏｎｅ）作了较为系统而深入的研究［１］，本文根据他所作的工作，采用非参数估...     

催化动力学光度法在痕量元素测定中的进展

动力学分析方法是以反应速率的测量为基础的定量分析的方法，其中催化动力学方法的研究和应用比非催化方法应用更为普遍。催化动力学光度法是一种动力学分析方法与分光光度法联用的分析技术。由于灵敏度和选择性都比较高，且操作简便，因而在痕量分析的应用发展迅速，其检出限可达到ng／ml甚至pg／ml级。本文就近两年来催化动力学光度法在痕量元素测定中的应用进展作一综述。     

多组分反应在杂环合成中的应用

多组分反应(MCRs)由于其高度的原子经济性、收敛性、出色的产率等特性以及在药物研究中先导物的发现和结构优化等方面的重要应用,在有机和药物化学领域发挥着越来越重要的作用。应用多组分反应构筑新的、具有各种生理活性的杂环化合物已成为杂环合成的重要手段之一。文章对多组分反应在杂环合成中的应用进展进行了综述。     

胶束体系动力学光度法测定痕量铝(Ⅲ)

在表面活性剂Tween-80存在下,在酸性介质中,痕量Al(Ⅲ)能灵敏地催化H2O2氧化甲基紫的褪色反应.通过研究该反应的最佳条件、动力学参数和机理,建立了催化动力学光度法测定痕量Al(Ⅲ)的新体系.方法的检出限为2.247×10-10g·mL1-,测定线性范围为0～0.8μg/25mL.其方法的选择性高,重现性好,一定量的常见离子不干扰测定,用于测定人发、豆样和水样中Al(Ⅲ),均获得满意结果.     

BP神经网络分光光度法在多组分体系分析中的应用研究

介绍了BP神经网络的基本原理，用BP神经网络分光光度法解决了多组分体系中各组分曲线相互重叠的问题，不需要用物理的、化学方法进行分离或掩蔽而测定出各组分的相对含量，具有简便、准确的优点。     

分光光度法同时测定钛铁矿中的钙和镁

研究了甲基百里香酚蓝络合剂与钙镁显色反应的条件，混合反应体系的吸收光谱，提出了一种新的同时测定钛铁矿中的钙和镁的分光光度法。该方法简便快速，将其应用于钛铁矿中的钙和镁的测定，效果良好，方法的准确度和重现性较好。测试结果令人满意。     

气相色谱法同时测定聚氯乙烯中的8种增塑剂

采用气相色谱法同时测定聚氯乙烯中的8种邻苯二甲酸酯增塑剂，该方法简便、快速、灵敏。     

甲醇脱水制二甲醚宏观反应速率的计算和测定

甲醇脱水制二甲醚宏观反应速率的计算和测定陈银飞，孙勤，葛忠华（浙江工业大学，杭州３１００１４）关键词：甲醇，二甲醚，宏观动力学１前言二甲醚作为一种甲基化剂，在制药、染料、农药等工业中有许多独特的用途。最近，有人提出并开发用二甲醚作为城市煤气或液化燃料...     

紫外光谱法在药物多组分同时测定中的应用

药物品分析常遇到混合物多组分的同时测定。化学计量法用于多组分的同时测定是一种简单、准确度高的分析方法。文章用多组分线性回归-紫外光谱法测定混合溶液中扑热息痛、咖啡因、扑尔敏含量。扑热息痛、咖啡因、扑尔敏的平均回收率、相对标准偏差分别为:93.62%,3.46%;93.16%,2.52%;106.08%,2.69%。     

Kinetic Study of Ozone Decay in Homogeneous Phosphate-Buffered Medium

The ozone decomposition reaction is analyzed in a homogeneous reactor through in-situ measurement of the ozone depletion. The experiments were carried out at pHs between 1 to 11 in H₂PO₄^?/HPO₄^2– buffers at constant ionic strength (0.1 M) and between 5 and 35 °C. A kinetic model for ozone decomposition is proposed considering the existence of two chemical subsystems, one accounting for direct ozone decomposition leading to hydrogen peroxide and the second one accounting for the reaction between the hydrogen peroxide with the ozone to give different radical species. The model explains the apparent reaction order respect of the ozone for the entire pH interval. The decomposition kinetics at pH 4.5, 6.1, and 9.0 is analyzed at different ionic strength and the results suggest that the phosphate ions do not act as a hydroxyl radical scavenger in the ozone decomposition mechanism.     

Monte Carlo Simulation of Multicomponent Aerosols Undergoing Simultaneous Coagulation and Condensation

A Monte Carlo method was developed to simulate multicomponent aerosol dynamics, specifically with simultaneous coagulation and fast condensation where the sectional method suffers from numerical diffusion. This method captures both composition and size distributions of the aerosols. In other words, the composition distribution can be obtained as a function of particle size. In this method, particles are grouped into bins according to their size, and coagulation is simulated by statistical sampling. Condensation is incorporated into the Monte Carlo method in a deterministic way. If bins with fixed boundaries are used to simulate the condensation process numerical dispersion occurs, and thus a moving bins approach was developed to eliminate numerical dispersion. The method was validated against analytical solutions, showing excellent agreement. An example of the usefulness of this model in understanding aerosol evolution is presented. The effects of the number of particles and number of bins on the accuracy of the numerical results are also discussed. It was found that with 20 bins per decade and 105particles in the control volume results with less than 5%error can be obtained. The results are further improved to within 2%error by filtering the statistical noise with a cubic spline algorithm.     

Multicomponent sorption kinetics of hydrocarbons in activated carbon: Simultaneous desorption and displacement

Binary desorption and displacement kinetics of ethane and propane in Ajax activated carbon are studied in this paper to further understand the multicomponent adsorption of light hydrocarbons onto activated carbon. The experimental data are collected using a differential adsorption bed over a range of temperatures, bulk concentration combinations, particle sizes and shapes. A macropore, surface and micropore diffusion (MSMD) model recently proposed by Hu and Do (Chem Eng Sci (1993) 48 1317) is used in the analysis of experimental data. This model takes into account the concentration dependency of the surface diffusivity. Both diffusions of free and adsorbed species are allowed for in the theory. The adsorbed species are assumed to diffuse in the particle as well as in the microparticle (grain) coordinates. An imaginary gas-phase concentration concept is used to calculate the local diffusion flux of the adsorbed species inside the microparticle. The local multicomponent adsorption equilibrium at any point within the particle is calculated using the ideal adsorbed solution theory (IAST), with the single-component adsorption equilibrium data described by a Unilan equation.     

Permeabilization of Aspergillus niger by Reverse Micellar Solutions and Simultaneous Purification of Catalase

Abstract

Reverse micellar solutions(RMS) of sodium bis‐ (2‐ethylhexyl)‐sulfosuccinate (AOT) in aliphatic organic solvents were used for permeabilization and protein removal directly from Aspergillus niger cells. Most of the cell wall proteins (～95–100%) were solubilized into the reverse micelles solutions. A significant fraction of intracellular catalase (26–30%) permeates out of the cells and remains on the cell surface and is recovered in a cell wash. Because of it's size the catalase in not solubilized in the RM water pools and thus is not detected in the stripping solution used to recover other proteins from the organic reverse micellar solutions. The remaining amount of catalase is recovered by breaking the cells in purer form. Multiple extractions were used for the extraction of the cell wall proteins followed by ultrasonication of the cells to recover intracellular catalase in a purified form. Therefore, catalase with 5 fold purification was recovered in 88% yield from the RMS‐ treated cells.     

Kinetic Model of Two‐Phase Epoxidation with Ionic Liquids as Micellar Catalysts

The biphasic catalytic epoxidation of cyclooctene using the ionic liquid (IL) 1,2‐dimethyl‐3‐octyl‐imidazolium perrhenate ([OMMIM]ReO₄) as micellar catalyst and H₂O₂ as oxidant was investigated. Kinetic experiments were carried out in the intrinsic kinetic regime as proved by variation of stirring rate and temperature. Variation of catalyst concentration allowed for determination of the critical micellar concentration (CMC) of the catalytic IL. The effect of substrate concentrations on the reaction rate was also assessed. Based on the experiments, a kinetic model adapted from enzyme catalysis was proposed to account for the micellar reaction environment. The model takes into account the onset of micelle formation at the CMC. The application of the kinetic model illustrated the good agreement with the experimental data. The model will be applied to other micellar epoxidation reactions and for the design of an appropriate reaction setup in the future.     

Kinetic Analysis of the Ozonation Process of the Surfactant LAS Considering the Simultaneous Foaming Effect

Advanced oxidation processes (AOP) are able to degrade pollutants into harmless substances. To demonstrate the successful application of AOP to real, polluted effluents, ozonation has been applied for the removal of linear alkylbenzene sulfonates (LAS), a surfactant mixture commonly used in detergent formulation. LAS can be identified in a wide range of concentrations, i.e., in domestic wastewater or in the raw effluent of detergent-processing plants. The strongly tensoactive nature of LAS results in a foaming effect that eventually discourages AOP application, especially in the case of ozonation. The primary goal of this research is to analyze the LAS ozonation kinetics, considering the simultaneous effect of foam formation, by the development of a semiempirical model that is mainly based on the foaming phenomenon. Along with foaming, the proposed model also considers LAS removal by ozonation and the inverse phenomenon of LAS formation by redissolution of LAS. To the best of our knowledge, such a finding has not been previously reported. The proposed foaming model has been developed within various pH and LAS concentration values, primarily examining the initial pH value of the effluent due to its significant effect on foaming. The developed model adequately predicts the LAS concentration profiles measured in the liquid during ozonation. Moreover, this approach makes it possible to quantify the incidence of foaming and LAS redissolution during ozonation comparatively, leading to being able to propose the most desirable operating conditions for LAS removal.     

多组分除草剂气相色谱分析方法研究

本文用气相色谱法分析扑草净－２甲４氯－除草醚混合粉剂中各成的分量。色谱柱为Φ３毫米×１米的不锈钢柱，柱内填充１Ｏ％１，２－丙二时己二酸聚酯／酸洗１０１白色担体，邻苯二甲酸二正丁酯作内标物。该法简便、快速、准确，回收率达９８．１～１Ｏ２．２％，变异系数小于４％，方法用于实样测定，结果令人满意