稀溶液的渗透压、化学势、外压与蒸气压关系

以外压对化学势的影响为主线,从外压对化学势的改变和外压对稀溶液蒸气压的改变两个方面,讨论了稀溶液的渗透压、化学势、外压与蒸气压关系。以帮助学生更好地理解和掌握这些基本概念。     

化学势概念的正确理解及应用

化学势概念的正确理解及应用杨永华（吉林大学化学系长春１３００２３）化学势的概念是物理化学中的基本概念之一。它在化学热力学、化学动力学、电化学及统计热力学中均有重要的应用。有关化学势的概念在各教材中都做了确切的定义和严谨的描述，但是在具体应用这一概念的...     

三维纳米液膜沉积结构的模拟研究

基于三维动力学蒙特卡罗模型,再现了纳米液膜干燥后形成的双尺度沉积结构,探究了液体化学势、纳米粒子移动速率、液体临界蒸发率以及化学势锐度等参数对纳米液膜沉积结构的影响。结果表明,纳米液膜干燥时,液膜中的纳米粒子随着三相线移动自组装形成各种各样的沉积结构沉积在基板上。纳米液膜蒸发过程中,当液体蒸发达到临界蒸发率时液体化学势将发生突变,使其形成两种沉积结构。随液体初始化学势的增大,沉积结构逐渐变为均匀分布的密集网状结构。液体临界蒸发率越小,液体化学势突变后形成的沉积结构越明显。纳米粒子的移动速率越快,沉积结构中的枝状结构越少。化学势锐度对双尺度沉积结构的差异有很大的影响,锐度越大,两种沉积结构的差异越大。     

化学势对模拟计算单壁纳米碳管储氢的影响

采用巨正则Monte Carlo分子模拟方法对单壁纳米碳管阵列的储氢性能进行了研究. 发现计算化学势时的误差可导致单壁纳米碳管氢吸附量较大的变化. 采用修正以后的化学势重新计算了298.15 K时单壁纳米碳管阵列的吸附等温线, 计算而得单壁纳米碳管的储氢量更接近实验结果. 另外, 通过与实验结果进行比较, 认为在单壁纳米碳管阵列的储氢过程中可能存在化学吸附过程.     

有限势库化学机最大输出功时循环最优构型

基于有限势容高化学势库和无限势容低化学势库间工作的等温内可逆化学机,在循环总时间一定的条件下,应用最优控制理论导出了一类普适传质规律下对应于最大输出功时化学机循环最优构型.特例分析表明传质定律为g∝△μ(△μ为化学势差)时循环最优构型为低化学势侧工质中关键组分的化学势(或浓度)为常数,而工质与有限势容高化学势库间关键组分的化学势(或浓度)均随时间呈非线性变化且化学势之差(浓度之比)为常数的等温内可逆化学机循环;传质定律为g∝△c(△c为浓度差)时循环最优构型与传质定律g∝△μ下循环最优构型存在显著不同;当高化学势库也为无限势容化学势库时,循环最优构型由两个等化学势传质分支和两个等质量流率分支组成,且与具体的传质定律无关.本文的研究对象具有一定的普适性,研究结果对于实际化学机的优化设计与最优运行具有一定参考价值.     

重力场热力学分析和重力化学势

用分析比较的方法对重力场热力学作了新思考，建立了重力场中的Ｇｉｂｂｓ方程和重力化学势，使处理方法简单通用，与普通热力学方法衔接起来，应用大为方便。     

Sandwich教学法在物理化学教学中的应用——以化学势表达式的推导为例

以化学势表达式的推导为例,探究了Sandwich教学法在物理化学教学中的应用。详细介绍了Sandwich教学法实施过程中教师如何提出问题以呈现教学目标,学生如何通过自主学习与全班交流来探究与解决问题,以及最后又如何通过总结与反馈回归教学目标。通过以学生为主体的Sandwich教学过程的实施,学生对化学势概念、热力学基本方程及状态函数法等重要的物理化学基本概念、公式及方法有了更深入的理解和掌握。Sandwich教学方法相较于传统教学模式更能激发学生学习的主动性和积极性,从而提高学生学习物理化学的兴趣与效果。     

固着纳米流体液滴颗粒自组装三维模拟

通过理论模拟固着纳米流体液滴在不同的蒸发模式与蒸发条件下会形成不同的沉积结构,有助于揭示纳米流体蒸发自组装机理并推动调控自组装过程方法的发展。建立了适用于小接触角纳米流体液滴蒸发的三维动力学蒙特卡罗(KMC)模型,引入随液滴厚度与相对半径变化的弧形化学势函数,并在其中加入了化学势衰减率,模拟了小接触角纳米流体液滴的蒸发过程,预测了枝状连续结构的形成。同时分别讨论了不同参数(初始化学势、纳米颗粒浓度、纳米颗粒扩散率)对液滴的蒸发过程与沉积结构的影响。模拟结果与两种实验结果进行了定性对比,结果吻合良好。     

稀溶液中化学势的计算以及渗透压公式的推导

将溶液中某组分化学势的计算方式归纳为两种:(1)利用气液平衡时,溶液中某组分的化学势和气相中该组分的化学势相等这一关系来计算;(2)利用溶液中某组分化学势的全微分表达式直接积分来计算。在此基础上,给出了渗透压公式的一种新推导方式,并指出部分物理化学教材关于渗透压定义(Π=p2-p1)的不合理性以及推导渗透压时存在的不妥之处。     

电极电势:从电化学势说起*

对于原电池,电极电势的本质是化学体系对电极材料上电子势能的影响,其正负极电势差反映化学能向电能转化的趋势。电极界面上化学物质的氧化/还原反应是通过何种途径影响到电极上电子势能的,现有的教材和论著没有给出明确的解释。本文基于相间电化学势平衡原则阐明了固液界面上离子平衡与电极上电子电势的关系,并由此给出了标准电势的物理含义:它是构成电极体系一系列物性参数的组合,包括被测电极的电子、离子化学势,工作电极电解液的离子化学势,参比电极的电子、离子化学势和参比电极电解液的离子化学势等。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.