螺旋霉素从水溶液中结晶成核动力学

通过测量在不同的加热速率下的最大过热温度得到了螺旋霉素在水溶液中结晶成核的动力学,实级成核速度ｍＮ．ｐ＝７．０８９ｅｘｐ「－１７．９９８×１０＾３（１／２９８．１５－１／Ｔ）．ｅｘｐ（－０．１１９／ｌｎ＾２ｓ）二次成核速率ｍＮ,ｓ＝０．３４１ｅｘｐ」－３．５０８×１０＾３（１／２９８．１５－１／Ｔ」．（ｃ－ｃａ）＾１．３９２并和光散射方法测定估计出初级晶核的大小约为０．０５μｍ。     

AF—5分子筛催化剂上苯气相乙基化反应失活动力学研究…

根据前文的实验结果，提出了苯和乙烯在ＡＦ－５分子筛催化剂上进行烷基化反应的失活动力学模型，乙烯引起的失活，芳烃引起的失活可按独立失活处理。通过理论分析和数据拟合确定了动力学参数和失活参数，得到了如下失活动力学模型。动力学方程（－ｒｅ）＝ｄｃｅ／ｄτ＝－５６．３７ｅｘｐ（－２４．２／ＲＴ）┿ｅ＾１＾．＾１ψ（ｍｏｌ／ｋｇｃａｔ·ｓ）活性程（－ｒψ）＝ｄψ／ｄｔ＝－［２．０２×１０＾－＾４ｅｘｐ（－１     

1,3—二氯丙烯水解反应动力学

本文研究了顺及反－１,３－氯丙烯混合物水解反应过程的动力学。结果表明,利用１０％ａＯＨ水溶液,在６５￣８０℃的条件下,顺及反－１,３－二氯丙烯的水解反应均为二级反应,顺、反异构体的表观活化能分别为８７．５１ＫＪ·ｍｏｌ＾－１和１１３．６０ＫＪ·ｍｏｌ＾－１,反应速率常数Ｋ顺＝２．６２×１０＾１０ｅｘｐ（－１０５２５．６／Ｔ）,ｋ反＝１．０９×１０＾１４ｅｘｐ（－１３６６３．１／Ｔ）。     

用离子交换树脂催化水解醋酸甲酯的反应动力学研究

研究了在常压下、温度为３０８～３２８Ｋ的范围内，用阳离子交换树脂作催化剂的醋酸甲酯催化水解宏观反应动力学。建立了实验条件下的动力学模型。研究了反应温度、催化剂浓度、水酯比、催化剂装填方式及进料中含甲醇等因素对催化水解的影响。实验数据采用拟均相二级反应动力学模型进行回归，得出醋酸甲酯催化水解的正逆反应活化能为３５．５和２９．５ｋＪ／ｍｏｌ。与催化剂浓度关联的最终速率表达式为：ｋ＋＝（５．３９２７９×１０－１０Ｃ－２．０７２０５９×１０－８）ｅｘｐ（－４．２７０／Ｔ）ｋ－＝（５．９１０６６×１０－１０Ｃ－１．５１５４３×１０－８）ｅｘｐ（－３．４２８／Ｔ）     

还原气氛中γ－906型催化剂上羰基硫水解动力学研究

于３０～７０℃、常压及还原气氛下，采用内循环无梯度反应器研究了Ｔ－９０６型催化剂上ＣＯＳ水解反应过程，实验数据以多元拟线性回归法处理得到本征动力学方程为：ｒｃｏｓ＝４·５９３×１０６ｅｘｐ（－ＲＴ）ｙｃｏｓｙＨ２ｏ宏观动力学方程为：ｒｃｏｓ＝１·０２５×１０５ｅｘｐ（－ＲＴ）ｙｃｏｓｙＨ２Ｏ确定了ＣＯＳ和Ｈ２Ｏ的反应级数分别为０．６６和０．０６．关键词：     

乙酸异戊酯杂多酸催化合成及其动力学研究

研究了以钨硅酸为催化剂,苯为带水剂乙酸和异戊醇直接酯化合成乙酸异戊酯的优化反应条件,该杂多酸催化反应的速率方程为－ｄＣＡ／ｄｔ＝ｋＡｃＡｃＢ,反应表现活化能Ｅａ＝１４２．５７ｋＪ／ｍｏｌ,反应速率常数ｋＡ（Ｌ·ｍｏｌ＾－１·ｍｉｎ＾－１）＝７．７５×１０＾１７ｅｘｐ（－１７１４８．２／Ｔ）。     

三聚氰胺净化湿法磷酸第二阶段反应动力学

研究了三聚氰胺结晶法净化湿法磷酸生产磷酸钠盐的第二阶段反应过程动力学特征，测定了反应过程的动力学数据。在液固反应扩散传质控制条件下，确定了反应过程的动力学方程为１－３（１－ＸＢ）Ｂ２３＋２（１－ＸＢ）＋ｋ∫ｔ０ＣＡＬｄｔ。式中ｋ符合Ａｒｈｅ－ｎｉｕｓ关系：ｋ＝６．１０×１０－３ｅｘｐ［－５．５２９／（ＲＴ）］。对模型的检验结果表明所得动力学模型的置信度在９５％以上。     

对硝基苯甲酸催化加氢本征动力学

用活性炭载钯催化剂,在排除扩散影响的条件下,研究了对硝基苯甲酸加氢的动力学。实验测定了氢气压力、温度、催化剂浓度等因素对反应速率的影响。研究结果表明：对硝基苯甲酸催化加氢反应为一级反应,表面化学反应活化能Ｅ＝２５．９１０ｋＪ／ｍｏｌ,原子氢吸附热ＱＨ＝３８．４８７ｋＪ／ｍｏｌ,其总括动力学方程为ｒ＝Ｋｃ２ＴＫＨαＰＨ（１＋ＫＨα·ＰＨ）２·ｃＡ其中：ｃ２ＴＫ＝４．０３５×１０３ｅｘｐ［－２５９０９．４９／ＲＴ］,ｍｉｎ－１αＫＨ＝５．０１３×１０－６ｅｘｐ（３８４８６．９３／ＲＴ）,ＭＰ     

甲基丙烯酸甲酯（MMA）生产中水解和酯化反应特性的研究

用间歇式搅拌反应器，对丙酮氰醇（ＨＣＮ）法甲基丙烯酸甲酯生产中水解和酯化反应的特性进行了研究。研究表明：（１）甲基丙烯酰胺硫酸盐的水解反应有较高的平衡转化率，其动力学方程为ｋ１＝６．５２×１０＾６ｅｘｐ（－６９．８／ＲＴ）；（２）甲基丙烯酸与甲醇间酯化反应的平衡转化率较低，故生产中必须加以提高。测得的液相和汽－液相酯化反应的活化能分别为４９．４ｋＪ／ｍｏｌ和５４．４ｋＪ／ｍｏｌ。     

合成三聚氯氰的氯化和聚合反应宏观动力学研究

利用非等温固定床反应器，研究了三聚氯氰合成的氯化和聚合反应宏观动力学，实验表明氢氰酸与氯气的氯化反应为气相均相反应，而氯氰的聚合反应为吸附在活性炭表面上的氯氰表面反应为控制步骤的气固催化反应。实验测得氯化反应的宏观反应动力学方程为对氢氰酸的一级反应，即（－ｒＡ）１＝２．４５×１０７ｅｘｐ（－２．９０×１０４／ＲＴ）ｃＡ测得聚合反应的宏观动力学方程为（－ｒＡ）２＝ｋ［ｐ３Ａ－ｐＲ／Ｋｐ］／［１＋ＫＡｐＡ＋ＫＲｐＲ］３ｋ＝４．０×１０７ｅｘｐ（－４．３５×１０４／ＲＴ）Ｋｐ＝６．７６×１０－２３ｅｘｐ（３．５２×１０５／ＲＴ）ＫＡ＝４．０×１０３ｅｘｐ（－３．３９×１０４／ＲＴ）ＫＲ＝１．０５×１０３ｅｘｐ（－５．０２×１０４／ＲＴ     

Die H2S-oxidation an aktiver kohle—ein elektrochemischer prozess?

Proceeding from the observation that a galvanic cell can be formed with activated carbon as electrode material and aqueous solutions of H₂S and oxygen, a mechanism is submitted for discussion, according to which the oxidation of H₂S catalyzed by activated carbon takes place by this very formation of cells on the microscopic surfaces of the carbon. The known effects of H₂O, H⁺ ions, as well as Fe and I content of the activated carbon on catalysis may be explained by this model.The catalytic inefficiency of dry activated carbon with respect to the oxidation of H₂S with oxygen-containing gases at ambient temperature is due to the fact that electrolyte is indispensable for electrochemical processes. Carbon hexagon layers with reversibly chemisorbed O₂ behave as oxygen electrode while layers with adsorbed H₂S act as fuel electrode. Only after addition of electrolyte elemental sulphur can separate on the fuel electrode.The pH value can drop far below pH 2 due to H₂SO₄ formed in a side reaction. With such acid concentrations, H₃S⁺ ions are increasingly formed. Since H₃S⁺ is no longer accessible to electrochemical oxidation, catalysis is retarded within these pH ranges.Iron bonded in complex form to the layers behaves as an electron acceptor. By this, the layers and the adsorbed H₂S are positively polarized which allows oxidation of the H₂S to sulphuric acid. The negatively polarized iron assumes the function of the oxygen electrode.Iodine blocks the direct access of H₂S to the layer or fuel electrode respectively. By direct chemical reaction, also within the strongly acidic range, elemental iodine reacts with H₂S forming elemental sulphur. The iodide ions formed are subject to electrochemical oxidation to I₂ on the carbon layer.The special advantage of the electrochemical oxidation mechanism is that the O₂ and H₂S molecules must not necessarily be in direct contact.     

Adhesion aspects of levulinic-acid-modified furan polymers to crystalline zinc phosphate metal surfaces

The nature of the interfacial interactions between functional levulinic-acid-modified furan resin coatings and crystalline zinc phosphate hydrate films deposited on carbon steel surfaces has been systematically investigated. The typical surface topography of the highly crystallized zinc phosphate films was found to be characterized by the presence of a dendritic microstructure array of interlocking triclinic crystals. This structure acts significantly to develop mechanical interlocking bonds with the functional blend polymer which penetrates into the open surface structure of the films. Both the thickness of deposition film and the polar H₂O molecules of hydrate at the outermost film surface sites play essential roles in wetting by the functional liquid resin. When the polarized furan polymers spread on the oxide film surfaces, the carboxylate groups derived from the levulinic ester and acid molecules react to form strong hydrogen bonds with the crystallized H₂O molecules on the hopeite film. This formation of hydrogen bonding was shown to be a major factor affecting the chemical intermolecular attractions. A formulation consisting of 95 parts furan to 5 parts levulinic acid was found to yield the optimum protective coating. More than 5 parts levulinic acid resulted in the transformation of the characteristics of the polymer film from hydrophobic to hydrophilic.     

乙烯气相氧乙酰化反应机理和动力学研究

采用阶跃应答技术研究了乙烯Ｐｄ－Ａｕ－ＫＡｃ／ＳｉＯ２催化剂上气相氧乙铣化合成蜡酸乙烯过程主副反应的机理，结果表明：分子态吸附氧是生成目的产物醋酸乙烯的氧源，而原子态吸附氧是生成副产物二氧化碳的氧源，在工业条件下，主副反应动力学方程仅是氧化压的函数，主反庆级数为１级，副反应级数为０．５级，在反应机理研究的基础上，进一步研究确定了乙烯气相氧乙酰化过程的反应的网络和动力学参数。     

浸渍活性炭脱除H_2S固定床反应器模型(Ⅰ)──数值分析

建立了浸渍活性炭固定床脱硫反应器数学模型,并用逼近的微分──差分方法进行求解,以此讨论了固定床反应器内气体脱硫过程的一般规律.模拟结果表明,在较低空速下操作以及使用较小颗粒的脱硫剂可以延长床层的使用寿命,提高操作硫容量,而与进料浓度无关.     

Water vapour adsorption on lignin‐based activated carbons

Lignocellulosic wastes are interesting precursors for carbon products. The high amount of Na observed in kraft lignin makes it a promising precursor for the preparation of activated carbons for desiccant applications. Water adsorption capacity and kinetics of kraft lignin‐based chars and activated carbons with different burn‐off and inorganic matter content have been studied. CO₂ partial gasification of lignin char develops a wide porous structure. An increase of the micropore volume can be observed at low to medium burn‐offs. At degrees of higher activation the mesoporous structure develops. For very high burn‐off the porous structure is destroyed by coalescence of the pores and reduction of the carbon material. The carbons obtained show atomic surface concentrations of sodium from 7.6–15.4%, as revealed by XPS analysis. Water vapour adsorption isotherms have been obtained in a thermogravimetric system and have been fitted by a DS model, which properly represents the experimental data. The kinetics of water vapour adsorption follows a linear driving force mass transfer (LDF) model. The presence of sodium and oxygen surface groups on the carbon surface enhances water vapour adsorption at low relative pressure. Activated carbon produced at 41% burn‐off shows the highest water vapour adsorption at low relative pressures, as a consequence of the high sodium dispersion on its surface. The sodium dispersed over the carbon surface undergoes clustering as gasification proceeds, decreasing the number of active centres. For burn‐off higher than 41%, this behaviour produces a decrease in the water adsorbed at low relative pressures. Copyright © 2007 Society of Chemical Industry     

活性炭吸附Zn(Ⅱ)的热力学与机理研究

本文研究了水溶液中活性炭吸附Ｚｎ＾２＋的热力学特性及其机理,测定了不同温度下的吸附等温线。结果表明;在稀溶液中吸附Ｚｎ＾２＋符合Ｌａｎｇｍｕｉｒ模型;活性炭吸附Ｚｎ＾２＋时可能主要是以水合Ｚｎ（Ｈ２Ｏ）＾２＝ｎ形式被吸附的;活性炭表面存在含氧官能团的吸附活性中心;由于吸附水合Ｚｎ＾２＋与炭表面含氧官能团之间相互作用,导致水分子的脱附及Ｈ＾＋的产生,使其热力学函数ΔＳ＾０增加。     

The kinetics of sputtered deposited carbon on silicon: a phenomenological model

A phenomenological model based on the rate equations for the carbon sputter deposition on Si surface is proposed. The processes of carbon adsorption, formation of SiC and transition from sp² to sp³ sites induced by low energy ion bombardment are included. The calibration of the model was performed with the experimental results. The amorphous carbon films were deposited by magnetron sputtering of graphite with Ar⁺ ions. The energy of ions bombarding the growing film was varied by applying a bias voltage on the substrate. It is shown that the non-monotonous kinetics of film growth is determined by the variations of surface composition at different stages of growth.     

Electrochemically grown passive films on carbon steel (SAE 1018) in alkaline sour medium

Corrosion films were prepared by applying cyclic potential pulses to the 1018 carbon steel-sour medium interface (1 M (NH₄)₂S, 500 ppm CN⁻) for 1 min. Electrochemical behavior and surface morphology of these films were determined using electrochemical impedance spectroscopy (EIS), scanning electron microscopy, and scanning photoelectrochemical microscopy (SPECM). EIS diagrams and SPECM images show the passive properties and homogeneity of the films. Furthermore, X-ray photoelectron spectroscopy (XPS) was used to characterize their chemical nature and structure. XPS results show that different oxide and sulfur structures were developed during the electrochemical oxidation of carbon steel in concentrated sour media. The analysis of O 1s data indicated that, during film growth, H₂O and/or hydroxyl groups are incorporated into the film structure. The XPS spectra of Fe 2p show iron bonds with S as iron sulfide (FeS₂ and FeS) and the corresponding peak of O 1s shows those bonds with oxygen as Fe₂O₃ and/or FeO. XPS depth profile analyses for the film showed that the ratio of FeS and FeO increases from film surface to film-carbon steel interface. This corroborates the diffusion of iron ions through the film during its electrochemical growth. The chemical shift through the film for the peak associated with Fe 2p signal proves that transport mechanism of iron ions through the film is carried out by chemical diffusion.     

活性炭担载金属氧化物用于热煤气脱硫

以热煤气脱硫并回收单质硫为目的,考察了活性炭担载金属氧化物(M/AC)在中温范围150—250℃内,催化氧化硫化氢生成单质硫的研究。担载量1%(质量分数)的M/AC通过等体积浸渍法制得,在固定床上评价了其脱硫活性,并考察了温度、反应气氛等工艺条件对脱硫效果的影响。M/AC脱硫的活性顺序为:Mn/ACCu/ACCe/ACFe/ACCo/ACV/AC。通过DTG分析,硫化氢选择性氧化的主要产物是单质硫。M/AC上金属氧化物起主要的催化作用,催化硫化氢和氧气反应生成单质硫,生成的单质硫被吸附在活性炭的孔道中。     

Kinetics and reaction mechanism of hydrogen sulfide oxidation over activated carbon in the temperature range of 125–200°c

The kinetics and reaction mechanism of the oxidation of hydrogen sulfide over activated carbon were studied in the temperature range 125–200°C. The heats of adsorption of oxygen and H₂S were found to be 73.8 and 16.0 kJ/mol, respectively, in the above temperature range. The sorption constants and the reaction constant have been expressed as a function of temperature. The role of water in the oxidation reaction has been clarified. No evidence was found to show that sulfur catalyzes the oxidation reaction.