纳米CeO2搀杂对Ni-P化学镀层微观结构与耐蚀性能的影响

引言 化学镀Xi-P镀层因其良好的耐磨性、耐蚀性及可焊性而被广泛应用于化工、航空航天及电子封装领域[1-2].镀层的力学性能及化学稳定性主要取决于其内部的微观结构及磷含量,此外,镀层在高温条件下的相变规律也被广泛研究[3-6].     

Co-Ni/y-Al2O3催化剂上乙醇催化氨化合成乙腈反应的本征动力学

引言乙腈是一种重要的溶剂和化工原料,广泛用于有机合成、农药、医药、石油化工、表面活性剂以及高分子材料等领域.此外,由于高纯乙腈对紫外线的吸收为零,并且具有独特的物理化学性质,因此,乙腈在高压液相色谱、电化学以及分光光度法分析中作为溶剂广泛使用[1].目前,工业上主要通过分离丙烯氨氧化合成丙烯腈过程的副产物乙腈的方法得到乙腈[2].这种方法得到的乙腈纯度差,并且产量受丙烯腈需求波动的影响.     

Saccharomyces cerevisiae在加压和超临界CO2中的变化

引言 超临界萃取过程在制药、食品、中药和天然产物提取等领域有广泛的应用前景,其中二氧化碳是最常用的超临界溶剂[1-2].作为过程强化的一种手段,使用超临界流体在线萃取抑制性的发酵产物,可提高底物的转化率和产物的收率.然而,加压或超临界CO2对微生物存活率和代谢活性有副作用[3-4].     

考虑非稳态自然对流的固体溶解过程数值模拟

引言固体在液体中的溶解是自然界中常见的一种现象,广泛存在于化工、药物研究、食品生产等领域[1-3]。大量的研究者从实验和理论两个方面对固体溶解过程进行了广泛的研究[4-6]。Marabi等[7]采用实验手段考察了溶剂的物理性质对单颗球形蔗糖在无限大溶剂中的溶解过程的影响;Vzquez-     

环氧树脂胶黏剂在石墨粘接接头的热分解动力学

引言 与传统的铆接、螺栓连接工艺相比,粘接技术因具有操作灵活、简便、生产效率高、生产成本低等优点,而广泛用于化工、汽车、航空、航天等现代结构工程,在工程设计和制造领域的应用持续增长[1-3].     

科研动态

<正>叶氏化工下属谦信化工荣获"十佳助剂溶剂品牌"叶氏化工集团有限公司(以下简称"叶氏化工"或"集团")下属江门谦信化工发展有限公司(以下简称简称"谦信化工")2014年再次荣获慧聪网"2013年度第十届中国涂料原料及设备十佳品牌评选"之"十佳助剂溶剂品牌",营销总监吴炼红代表公司出席了颁奖典礼,该荣誉彰显了公司在专注业务领域方面的优秀表现。溶剂是叶氏化工最大的核心业务。谦信化工作为全球最大的醋酸酯类溶剂生产商,是叶氏化工瞄准中国改革开放的发展机会,集团旗下子公司谦信化工发展有限公司于1993年与江门市启盛化工发展有限公司成为合作伙伴,凭借中外合资的优势,互相取长补短,联手打造     

N,N-二甲基甲酰胺(DMF)的生产与应用

一、前言虽然早在19世纪末期,就已由氢氰酸与甲醇[1]或与甲胺在水的存在下[2]合成了二甲基甲酰胺。然而,直到本世纪五十年代将其作为丙烯酸类纤维纺丝的溶剂后,它才在工业上受到特别的重视。目前二甲基甲酰胺已成为一种重要的有机化工原料,作为溶剂和催化剂广泛应用于纺丝、化工、轻工、医     

新型化工能源转化工艺及其碳减排研究

随着全球经济的快速发展,能源需求和碳排放问题日益严重,新型化工能源转化工艺在碳减排领域的重要性愈发凸显。本文论述了近年来新型化工能源转化工艺的研究进展,重点关注生物质化学品和能源技术开发、生物质基化学品催化过程研究、二氧化碳捕集新型溶剂的开发及化工过程强化、二氧化碳捕集与催化转化等方面的创新成果,并探讨了这些技术在碳减排中的应用前景,进而推动新型化工能源转化工艺在全球范围内的应用。     

液固循环流化床两相流动模型

引　言流化床换热器具有防、除垢和强化传热等优点 ,在化工、食品、海水淡化、废水处理等领域具有广阔的应用前景[1].目前 ,流化床换热器历经散式流化床、内循环流化床 ,已发展到外循环流化床换热器[2 ],它要求在较稀的颗粒浓度 (颗粒浓度小于 5% )、较高的流速 ( 1～ 3ｍ·ｓ- 1)下操作 .流化床换热器中液体流动及颗粒运动状态的研究对流化床换热器的设计和操作具有重要意义 ,但人们对循环流化床换热器中颗粒运动情况的研究还很缺乏 .考虑到循环流化床换热器中的每根换热管都可作为一个独立的循环流化床对待[3].本文试图建立一滑移速度模型…     

二吡啶酮配体四、六核钴簇合物的合成及结构表征

利用溶剂热反应,二吡啶酮与钴的乙酸盐反应得到两种新颖的四核和六核钴的簇合物[Co4(OH){(py)2CO(OH)}{(py)2CO}(O2CCMe3)6].3H2O1和[Co6{(py)2CO(OH)}2(O2CMe)8(DMF)(H2O)4].DMF.H2O2。晶体1的晶系数据:单斜,P2(1)/n,a=1.5784(9),b=1.7678(9),c=2.2615(13)nm,V=6.2857(6)nm3,F(000)=2672,finalR1=0.0795,wR2=0.1697[I>2σ(I)]。晶体2的晶系数据:单斜,P2(1),a=1.3721(10),b=1.4377(10),c=1.5541(10)nm,V=2.7813(3)nm3,F(000)=1436,finalR1=0.0370,wR2=0.0664[I>2σ(I)]。配合物1中有两个共边的Co3O单位组成了蝶式构型,而配合物2含有两个线形的三个Co原子组成的双锚结构。     

萘油组分的超临界萃取工艺研究

以乙醇为超临界萃取剂,利用恒容升温法对綦油组分中的萘、苊和芴进行超临界萃取工艺研究,对萃余液进行气相色谱检测,通过差量法计算其萃取率和超临界浓度,结果表明,超临界乙醇对萘油组分的萃取具有较好的效果,在萃取温度为270℃、萃取压力为13MPa时,萃取效果最好;萘、苊、芴3种物质超临界萃取规律明显;萘油组分的超临界乙醇萃取工艺绿色环保,切实可行。     

高压乙醇中的无限稀释扩散系数:实验测定与模型评价

The infinite diffusion coefficients of benzene, toluene, naphthalene, pyridine and p-nitroaniline in ethanol were measured by Taylor dispersion technique under 318-473 K and 0-16 MPa. The measurement accuracy of the established apparatus was first checked. The measured diffusion coefficient of the five organic solutes in ethanol did not change with pressure at low temperature, but it was significantly reduced with pressure increase when the temperature is higher than 373 K. Of the correlations available for polar solvents, the modified Wilke-Chang equation, the Yang-Zhang equation as well as the He-Yu equation were used to calculate the infinite diffusion coefficient. At low temperature,the three equations all agreed well with experimental results for both polar and non-polar solutes.However, the prediction accuracy was decreased sharply when the temperature was higher than 373 K,where the association factor of the solvent was varied with temperature as well as pressure.     

Mass transfer for dissolving solids in supercritical carbon dioxide Part II: Resistance in the porous layer

The internal mass transfer resistance was measured by dissolving naphthalene from a porous insoluble rod in a stream of supercritical carbon dioxide. Initially the pores of the porous medium (sintered bronze) were filled with naphthalene. During dissolution the naphthalene surface retreats into the porous rod and the length of the diffusion path increases. The tortuosity factor for the porous material was determined from experimental data. The temperature was varied from 35 to 55 °C, the pressure from 118 to 226 bar and the mean pore diameter was either 8 or 20 μm. The results show that the tortuosity factor does not depend on the pressure and pore diameter. This result was to be expected since the mean free path of the molecules is much smaller than the pore diameter. The average tortuosity factor, however, decreased with increase of temperature. From this temperature dependence surface diffusion of the solute absorbed on the pore wall is concluded to take place and thereby to contribute to the observed overall rate of mass transfer.     

超临界乙醇萃取萘的实验研究

采用恒容升温法研究了超临界乙醇萃取煤焦油重要组分萘的效果,讨论了萃取温度和压力对萃取效果的影响.结果表明,在温度为270℃、压力为13MPa时,萘的超临界浓度为1.739×10^-2g/mL、萃取率为66.20％.     

CO2萃取分离离子液体［bmim］［PF6］与萘的高压相平衡

采用紫外光谱在线检测的静态相平衡方法,在温度313～333 K、压力8～20 MPa、萘的液相浓度0.0169～0.378 mol·kg^-1的范围内,测定了CO₂+［bmim］［PF₆］+萘三元系中萘在富含CO₂相的浓度。结果表明,在所测温度和压力范围内,萘在富含CO₂相的浓度随着温度的升高而减小,随着压力的升高而增大,而且随着萘在液相中的浓度的减小而减小。在一定的温度压力条件下,萘在富含CO₂相的浓度与萘在液相中的浓度近似呈双对数线性关系。采用Chrastil缔合模型关联了所有溶解度数据,平均相对偏差为14.9 %。此外,还探讨了CO₂萃取分离离子液体与高沸点有机物的操作模式,发现釜式间歇操作较为适宜。     

Z-藁本内酯在超临界CO_2中无限稀释扩散系数的测定与计算

在温度305.15~323.15 K、压力10~18 MPa范围内,采用Taylor峰扩展法测定了Z-藁本内酯在超临界CO2中的无限稀释扩散系数。结果表明,扩散系数范围在(2.75~5.55)×10-8m2/s之间,并随温度升高而增大,随压力和超临界CO2密度增大而减小,当温度和压力一定时,改性剂乙醇含量的增加能促进扩散系数缓慢增大。分别采用修正的Wilke-Chang、Scheibel、Lusis-Ratcliff、Reddy-Doraiswamy、He-Yu-Su模型预测了Z-藁本内酯的扩散系数,与实验测定值对比表明,平均绝对偏差分别为9.352%、9.356%、9.354%、9.360%和10.444%,均能很好的预测Z-藁本内酯在超临界CO2中的无限稀释扩散系数。     

Diffusion coefficients of naphthalene and caffeine in supercritical carbon dioxide

An experimental set-up is presented with which the diffusion coefficients of naphthalene and caffeine in supercritical carbon dioxide may be determined. The experimental conditions range from 118 to 226 bar and from 35 to 60 °C. The method consists in evaporating the component to be analyzed out of capillaries into supercritical carbon dioxide. The diffusion coefficient can be calculated from the amount of evaporated material during an experimental run. The method is of the pseudo-steady-state type, whereas diffusion coefficients of naphthalene in carbon dioxide given in the literature were obtained with an unsteady-state method. Depending on experimental conditions, the unsteady method yields slightly lower values than the pseudo-steady method. It can be shown that the strongly non-ideal behavior of the gaseous phase restricts the range of application of the unsteady method.     

Diffusion coefficients of supercritical carbon dioxide and its mixtures using molecular dynamic simulations

Molecular dynamic simulations have been evaluated for systems containing supercritical carbon dioxide to predict high-pressure diffusion coefficients of binary mixtures. Diffusion coefficients of high boiling compounds in supercritical fluids are important for the design of supercritical extractors, separators and reactors. Since high-pressure experiments are time intensive and difficult to perform, molecular simulations could prove a useful framework to obtain thermodynamic properties; however, their reliability is still in question. In this work, an NVT ensemble single site model molecular dynamic simulation using gear predictor corrector algorithm has been applied to calculate diffusion coefficients of carbon dioxide, naphthalene, 2,6-dimethylnaphthalene and 2,7-dimethylnaphthalene in supercritical carbon dioxide system at 317.5 K. The Lennard-Jones (12?C6) and the Coulomb potential function have been combined into an intermolecular potential function to measure the binary molecular interaction. The simulation results of the diffusion coefficients are being compared with similar experimental data near the critical points. The calculated diffusion coefficients for each system behaved as a monotonic decreasing function of the molar density and the molecular simulations results, and the selected experimental data are in good agreement.     

EFFECTS OF ENTRAINERS ON THE PHASE EQUILIBRIUM OF SUPERCRITICAL FLUID EXTRACTION PROCESS

A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.     

超临界或高压CO2中无限稀释扩散系数的模拟

采用分子动力学模拟的方法对超临界二氧化碳的自扩散系数及甲醇和乙醇在超临界二氧化碳中的无限稀释扩散系数进行了模拟计算。结果表明,分子动力学模拟方法可较准确地反映二氧化碳的扩散性质,计算无限稀释扩散系数取得了与实验值较吻合的结果。采用这种新方法可以准确有效的地预测超临界体系的扩散性质,将会更加广泛应用于工程设计,因此分子动力学模拟作为先进的研究手段会得到越来越广泛的应用。