国内外典型教材的热力学教学内容及教学思路比较

目前物理化学教学在“量子先行”和“热力学先行”两种策略的选择上依然存在争论,热力学是物理化学的重要组成部分,本文分析和比较了国内外10本典型教材在热力学教学内容安排上的现状,提出了发展方向和建议,希望对物理化学教学和教材建设提供依据。     

物理化学中的热力学方法、拓展及应用

主要依托物理化学中的热力学基本原理,浅议热力学方法、简介化工热力学方法和工程热力学方法及应用等。热力学方法主要有循环法、特性函数法、变量变换法、标准状态法、平衡法及极值法、微元法等,并归纳了各种方法的特点、作用及意义。对于学生学习物理化学中的热力学,具有一定的指导意义,拓展了热力学的基本知识。     

牛磺酸改性埃洛石纳米管的制备及其对四环素的吸附性能

四环素在环境中难于降解,容易残留在环境中,影响生态系统和人体健康。埃洛石纳米管是一种天然硅酸盐矿物,具有均匀的纳米中空管状结构。本文通过化学键合以牛磺酸对埃洛石纳米管表面进行修饰得到改性的埃洛石纳米管(HNTs-Tau),显著提高其对四环素的吸附能力。系统研究pH、吸附时间、吸附温度及离子强度对吸附性能的影响。结果表明,HNTs-Tau在pH=6的弱酸性溶液下吸附效果最佳。振荡时间为2 min时,去除率可达到90%以上。在25℃下采用10 mg HNTs-Tau对800μg/mL的四环素溶液的吸附容量可以达到512.5 mg/g。采用4种动力学模型拟合,HNTs-Tau对四环素的吸附行为更加符合准二级动力学模型。采用2种热力学模型拟合,HNTs-Tau对四环素的吸附行为更加符合Freundlich模型,对四环素的最大吸附容量可以达到714.3 mg/g。     

气液色谱法研究双—(O,O''''—二正辛基二硫代磷酸酯)合镍(Ⅱ)与五员杂环化合物加合反应的热力学性质

气液色谱法是研究酸碱相互作用热力学性质的有效方法之一,适合于气液表面化学反应的研究,可以得到一些用其他方法难以获得的热力学参数,丰富了表面化学领域的研究,具有重要的理论意义和应用价值。文献[1—4]利用气液色谱法测量了Ni[THDD]_2、Ni[(C_8H_(17)O)_2PS_2]_2与含氮、含氧有机碱加合反应的平衡常数、标准焓变和标准熵变值。作为酸碱加合反应研究的一部份,本文测定了Ni[C_8H_(17)O)_2PS_2]_2与五员杂环化合物呋喃、噻吩和吡咯反应的热力学参数。     

多壁纳米碳管修饰玻碳电极不可逆双安培法测定Fe~（3＋）

在玻碳电极上成功制备了多壁碳纳米管（MWNTs）修饰玻碳电极（GCE）,并对其进行显微表征。研究表明,该修饰电极（MWNTs/GCE）对Fe3＋具有明显的电催化还原作用。将其用于流动注射不可逆双安培（FI-IB）体系的构建,即：利用Fe3＋在MWNTs/GCE上的还原和硫酸羟胺（（NH2OH）2.H2SO4）在另一支金...     

Theoretical Study on Thermodynamic Properties and Hydrophilicity of Polychorinated Phenothiazines （PCPTZs）

The thermodynamic properties of 135 polychlorinated phenothiazines (PCPTZs) in the standard state are calculated using a combination of quantum mechanical computations performed with the Gaussian 03 program at the B3LYP/6-311G** level, and their octanol-water partition coefficients (logKow) are calculated based on group contributions. The chlorine substitution pattern strongly influenced the thermodynamic properties and hydrophilicity of the compounds. The thermodynamic properties of congeners also depend on the chlorine substitution pattern. The effect of chlorine substitution pattern is quantitatively studied by considering the number and position of Cl atom substitution (NPCS). The results show that the NPCS model may be used to predict the thermodynamic properties and hydrophilicity for all 135 PCPTZ congeners.     

沃特世科技(上海)有限公司成都分公司成立

为推进西南地区市场的拓展、更快地响应并服务西南地区客户,沃特世科技(上海)有限公司于2011年8月在成都设立了新的分公司,这是沃特世公司(Waters)继上海总部、北京、广州分公司之后在中国大陆成立的第三家分公司,这     

Theoretical Study and NBO Analysis of the Decomposition Kinetics of Oxetane, 2-Methyloxetane and 2,2-Dimethyloxetane

A theoretical study of the thermal decomposition kinetics of oxetane (1), 2-methyloxetane (2), and 2,2-dimethyloxetane (3) has been carried out at the B3LYP/6-311+G**, B3PW91/6-311+G**, and MPW1PW91/6-311+G** levels of theory. The MPW1PW91/6-311+G** method was found to give a reasonable good agreement with the experimental kinetics and thermodynamic parameters. The decomposition reaction of compounds 1～3 yields formaldehyde and the corresponding substituted olefin. Based on the optimized ground state geometries using MPW1PW91/6-311+G** method, the natural bond orbital (NBO) analysis of donor-acceptor (bond-antibond) interactions revealed that the stabilization energies associated with the electronic delocalization from σC3-C4 bonding to σ*O1-C2 antibonding orbitals decrease from compounds 1 to 3. The σC3-C4→σO1-C2 resonance energies for compounds 1～3 are 2.63, 2.59 and 2.45 kcal mol-1, respectively. Further, the results showed that the energy gaps between σC3-C4 bonding and σ*O1-C2 antibonding orbitals decrease from compounds 1 to 3. Also, the decomposition process in these compounds are controlled by σ→σ* resonance energies. Moreover, the obtained order of energy barriers could be explained by the number of electron-releasing methyl groups substituted to the Csp3 atom (which is attached to oxygen atom). NBO analysis shows that the occupancies of σCsp3-O bonds decrease for compounds 1～3 as 3<2<1, and those of σCsp3-O bonds increase in the opposite order (3 > 2 > 1). This fact illustrates a comparatively easier thermal decomposition of the sCsp3-O bond in compound 3 compared to compound 2, and in compound 2 compared to compound 1. NBO results indicate that these reactions are occurring through a concerted and asynchronous four-membered cyclic transition state type of mechanism.     

DFT Study on the Correlation between Thermodynamical Property and Molecular Structure of Polybromo-phenoxathiin

Complete optimization was conducted for 136 polybromo-phenoxathiin congeners(PBPTs) on the B3LYP/6-31G* level with Gaussian 03 program.The structural parameters and thermodynamical parameters of each molecule were obtained under the standard state of 298.15 K and 1.013×105 Pa.Reverse linear regression was employed to establish the quantitative structure-property correlation models between heat capacity at constant volume(CVθ),entropy(Sθ),standard heat of formation(△fHθ) and standard free energy of formation(△fGθ) of PBPTs and the structural parameters(the most negative atomic charge(q-) and molecular average polarizability(α)).These models presented better correlations(r20.97).And they were validated by variance inflation factor(VIF) and t-test,which can better explain the regularity of thermodynamical property of PBPTs,and has good stability and great prediction ability.     

间氨基酚修饰超高交联吸附树脂的合成及吸附性能

合成了间氨基酚修饰超高交联吸附树脂(MMAR)。用红外光谱等进行表征,并用于吸附水溶液中2-氨基吡啶的研究。热力学研究结果表明,Freundlich吸附等温方程能够对静态吸附等温线进行很好的拟合。吸附焓变ΔH0,其绝对值小于46 KJ.mo-l1,表明以物理吸附为主以及该吸附剂容易脱附的特征;△G0,说明吸附是自发行为;△S0,表明吸附质分子在树脂表面上的运动受到了限制。动力学研究结果表明,吸附符合一级动力学方程,吸附速率随着温度的升高而增大,颗粒内扩散是速率控制步骤之一。表观活化能Ea10 KJ.mo-l1,说明吸附较容易进行。