二苯二硫醚的结构和性质的理论研究

采用Materials Studio中的Dmol3程序对二苯二硫醚的结构和相关性质(键角键长、Mulliken电荷、振动强度、热力学性质、分子得失电子能力和稳定性)进行了理论性研究。通过Dmol3中的geometry optimization计算出各原子的电荷、振动频率等性质。计算结果明二苯二硫醚分子容易得到电子,并且两个硫原子可能是与其它物质亲电反应的作点。     

As_nP_(4-n)(n=1-3)分子结构和性质的理论研究

为了提供杂原子四面体AsnP4-n(n=1-3)的更多的结构和性质方面的信息,利用B3LYP/6-311++G**理论研究了P4,AsP3,As2P2,As3P和As4分子在气相的几何体结构并进行了解析振动频率的分析。采用Dmol3程序在GGA,BLYP/DNP和LDA,PWC/DNP理论水平上研究了五个分子的能量和电离势,通过分析能量得出了五个分子的稳定性是依次减弱;通过比较电离势的大小得出五个分子失电子的能力依次增强。基于统计热力学,求得温度298.15~1000.00K范围五个分子的熵、热熔,焓及吉布斯自由能的大小。     

二苯并噻吩结构和性质的理论研究

为了探究煤中噻吩类有机硫化合物降解规律,采用密度泛函理论来对煤的一种含硫模型化合物进行量子化学方面的计算与研究。采用Materials Studio中的Dmol~3程序分析了与煤有关的含硫模型化合物二苯并噻吩(DBT)的结构和相关性质(键角键长、电荷、振动频率、热力学性质、分子反应活性及稳定性)。计算结果显示处于噻吩环结构中的C—S键键能和C—C键键能相等,噻吩环中的C—S键键能大于非环中的C—S键键能;预测噻吩中C—S键更难断裂;模型化合物中的S原子处HOMO伸展较大,是给电子的位置,S原子易失去电子发生反应。     

几种拟除虫菊酯杀虫活性与电子结构关系研究

采用密度函数理论(DFT)在#PB3LYP／6-31G^y计算了氯菊酯、氯氰菊酯和溴氰菊酯的电子结构,用分子中原子的净电荷、能量讨论了杀虫剂杀虫活性的差异。     

有机共晶中分子带电荷性质的理论研究

本研究选取2种典型的有机共晶体系芘-八氟萘晶体和芘-1,2,4,5-四氰基苯晶体,采用密度泛函理论方法研究其分子带电荷性质,同时系统考察分子堆积对其电荷的影响规律。计算表明有机共晶中分子堆积结构能显著影响分子间的电荷转移,且采用最稳定的两体分子可以近似描述有机共晶中的电荷转移性质。     

应用于OLED的Ir(Ⅲ)系列配合物磷光性质的DFT和TDDFT研究

过渡金属配合物由于其分子和电子结构的多样性已成为催化、分析化学、生物科学以及光电技术等诸多领域的重要研究课题。特别是在发光材料领域,过渡金属铱和铂的配合物,由于重金属原子的引入使其可以有效的利用三线态激子的辐射衰减来提高电致发光效率,进而引起了人们的极大兴趣。过渡金属配合物自旋轨道耦合能力强,能有效混合单重态和三重态激子,使电致发光器件内部量子产率达到100%,是理想的电致发光材料。本文利用理论计算方法研究了一系列过渡金属Ir(Ⅲ)配合物的几何结构、前线分子轨道性质、磷光光谱和电致发光性质。计算结果表明,辅助配体结构的改变对配合物电子结构和光谱性质有很大的影响。同时,本文中所研究的配合物都具有较好的空穴传输性质及电荷传输平衡的性能。     

用密度泛函理论研究LAX-112与氟化氢分子间的相互作用

在DFT-B3LYP/6-311++G**水平上,计算获得3,6-二氨基-1,2,4,5-四嗪-1,4-二氧化物(LAX-112)与氟化氢(HF)超分子体系势能面上3种全优化几何构型。经基组叠加误差(BSSE)和零点能(ZPE)校正,求得LAX-112与HF分子间的最大相互作用能为-34.41kJ/mol。超分子体系中的电子均由LAX-112向HF转移。用自然键轨道(NBO)分析揭示了分子间的相互作用主要由强氢键所贡献。对优化构型进行了振动频率计算,结果表明,超分子体系中H-X(X=N和F)的伸缩振动频率均发生了大幅度红移。基于统计热力学求得200.0～800.0K温度范围从单体形成二聚体的热力学性质变化,发现二聚过程在较低温度或常温下均能自发进行。     

异氰酸酯交联环氧树脂非线性光学性质的计算化学研究

利用计算化学方法,采用密度泛函理论研究了一系列异氰酸酯交联环氧树脂单体分子(简称单体分子)的非线性光学性质及激发态性质。结果表明:引入取代基可以提高单体分子的非线性光学性质,但取代基的引入对单体分子的电子光谱几乎没有影响,因此对其透明性也不会有影响;引入氟代烷基使单体分子的偶极矩增大,但电荷的跃迁密度下降,随着氟代烷基碳链的增长,单体分子的非线性光学性质的增益效果很快收敛;引入烷氧基则对电荷跃迁性质影响较小,但增加了分子的偶极矩,从而增强了非线性光学性质。     

环氧绝缘材料对电气工程中电荷积聚过程的影响因素分析

高压直流输电过程中,环氧绝缘材料由于电荷积聚而导致击穿或放电效应,严重影响电网安全运行。通过直流实验装置,借助电容探讨法,针对环氧绝缘材料表面电荷进行测量,并利用Ansoft软件计算电极表面静电场,获得表面电荷分布情况,建立环氧绝缘材料电气性能和电荷积聚的关系。结果表明,平面指向性双电级表面电荷表现为显著的双极性积聚特性,即阳极侧积聚正电荷,阴极侧积聚负电荷;随电压作用时间的延长,环氧绝缘材料电荷趋于饱和,电荷积累速度逐渐下降,并趋于稳定;随着电压等级的变化,近电极区表面电荷密度不断增大,中间区趋于稳定,当电压提高到8 kV时,由于气体侧局部放电,电荷密度出现激增。     

多取代苯胺溶解度和电离常数的单参数预测

采用DFT理论方法与基组B3LYP/3-21+G,模拟了10种单取代苯胺分子的骨架结构。计算了其苯胺环上氮和氢原子的自然轨道电荷(NBO)和密立根电荷(Mul)值。结果发现,该电荷值与其实验溶解度系数(pK_s)和实验电离平衡常数(p Ka)值间有好的单参数关联性。另外还计算了10个多取代基的苯胺分子的氮和氢原子的自然轨道电荷和密立根电荷参数,使用拟合出的两线性方程,结果显示新方法预测值与ACD/Labs方法得到的多取代苯胺分子的pK_a/pK_s值接近。     

Investigation of the Correlations Between Nitro Group Charges and Some Properties of Nitro Organic Compounds

The so‐called nitro group charge method (NGCM) is successfully established to investigate some properties of nitro compounds including the molecular stability measured by total energy (only for isomers), the bond lengths, bond dissociation energies (BDE), and the nitrating activities, in that the method considers the molecular structure. These properties are intrinsically and especially thermodynamically consistent with each other and can be well related qualitatively and even quantitatively with nitro group charges (Q_Nitro). The correlations between Q_Nitro and the properties are: (1) for nitro isomers, the more negative the average Q_Nitro, the lower the total energy and the more stable is the isomer; (2) for any separate group of nitro compounds, the more negative Q_Nitro, the shorter the R‐nitro bond length; (3) for the bond dissociation energy, more negative Q_Nitro corresponds to a higher BDE of the R‐nitro bond; (4) by NGCM, the conditions, the reaction rates and the occurrence ratios of products of some nitration can be predicted and compared: the more negative Q_Nitro of the product, the easier and faster the nitration, and the higher the occurrence ratio of the corresponding product.     

Mechanical behaviour of porous lanthanide oxide microspheres: Experimental investigation and numerical simulations

Actinide oxide microspheres are considered as promising substituents to powder precursors for the production of ceramic pellets of nuclear fuel or targets. Porous microspheres of sub-millimetric size are synthesised using the Weak Acid Resin process. Controlling their microstructure and their mechanical properties is essential to predict the microstructure of green compacts and sintered pellets. Here, cerium and gadolinium are used to mimic actinides as metal cation. Single microspheres are crushed experimentally using a micropress in a Scanning Electron Microscope (SEM) to investigate their mechanical properties and visualise their fracture behaviour. The results are compared to numerical simulations based on the Discrete Element Method (DEM). In DEM, a microsphere is modelled as an assembly of bonded spheres representing aggregates. Bonds may fracture in tension or shear. A limited number of material parameters (aggregate elastic modulus, bond strength) are sufficient for the accurate simulation of the fracture behaviour of a microsphere.     

Some Preliminary Observations on the Catalytic Fading of Dye Mixtures

The ‘catalytic fading’ of C.I. Acid Violet 4 in the presence of C.I. Acid Yellow 112 has been investigated in solution, on films and on fibres. Trace amounts of an impurity have been isolated from C.I. Acid Yellow 112. This impurity has been shown to fade C.I. Acid Violet 4 catalytically. Examination of the impurity and comparison of its properties with those of the sodio derivative of ethyl acetoacetate suggest that it is a β-ketonic acid derivative present in part as an enolic sodium salt.     

Dyeing properties of CI Acid Blue 193 and the non‐equivalent properties of CI Acid Black 194 produced by different manufacturers

This paper presents the results of research conducted into the colour properties of commercial metal complex dyes CI Acid Blue 193 and CI Acid Black 194. Three chromium(III) complexes with different colours were identified using thin‐layer chromatographic analysis and then separated by preparative chromatography. It was found that colour differences of the examined dyes depend on the ratio of the three components in CI Acid Blue 193 and CI Acid Black 194, and that these differences are typical for each of the commercial products. The colour differences of the components were expressed as ΔS, calculated as the difference in the areas under the absorption curve of the individual components in the range 400–700 nm after spectrum normalisation. The UV‐vis spectroscopic and CIELAB colorimetric properties (at 1% owf on polyamide) of eleven samples of CI Acid Black 194 were investigated. From these results, the proportions of the three components were derived. Theoretically, dyes sold under the same CI name are interchangeable. In practice, the obtained colour of the dyed material is different owing to the difference in composition namely the ratio of the components in the tested dyes. Consequently, the result of polyamide dyeing with the studied dyes CI Acid Blue 193 and CI Acid Black 194 is a redder or greener hue. It has been concluded from these findings that the production of identical dyeings may be impossible when dyes from different sources are employed.     

Enzymatic Treatment of Pigment Prints

Extending from our previous work on applications of biotechnology in textile wet processing, this article reports the impact of post-biopolishing on the performance properties of pigment-printed cellulosic fabrics. The data demonstrate that the extent of enzymatic attack is determined by the nature of the cellulase enzyme, the depth of pigment prints, the nature of the cellulosic substrate, the fabric structure, and the finishing formulation contents. Furthermore, the loss in weight, the decrease in the depth of shade, and the improvement in softness degree of the biopolished pigment prints follow the descending orders:

Acid cellulases > Acid cellulases/softener > Neutral cellulase > None, None > Neutral cellulase > Acid cellulases/softener > Acid cellulases, and

Acid cellulases/softener > Acid cellulases > Neutral cellulase >> None, respectively.

The effect of enzymatic treatment on the fastness properties of the treated pigment prints were also investigated.     

Charge Density Distribution,Electrostatic Properties,and Impact Sensitivity of the High Energetic Molecule TNB: A Theoretical Charge Density Study

A quantum chemical calculation and a charge density analysis have been performed on the energetic molecule trinitrobenzene (TNB) to characterize its bond strength and to relate the bond topological parameters with the impact sensitivity. The optimized geometry of the molecule was calculated by the density functional method B3P86 with the basis set 6‐311G**. The bond topological analysis predicts a significantly low bond electron density (∼1770 e nm⁻³) as well as Laplacian of electron density (−1.67×10⁶ e nm⁻⁵) for C N bonds. This low value of the Laplacian indicates, the charges of these bonds are highly depleted, which confirms that these are the weakest bonds in the molecule. The N=O bonds bear a high negative value of Laplacian, reflecting that the bond charges are highly concentrated. The isosurface of the molecular, electrostatic potential (ESP) shows large electronegative regions at the vicinity of  NO₂ groups. Further analysis of ESP in the bonding region allows predicting the impact sensitivity. A sound relationship has been found between the ESP at the mid point of the bonds and its bond charge depletion. The positive ESP at the mid points of highly charge depleted C NO₂ bonds reveals that these bonds are the sensitive bonds in the molecule.     

1,2-丙二醇选择性氧化制备乳酸催化体系的研究

乳酸的生产方法主要有发酵法、乙醛氢氰酸法和丙烯腈法。对选择性氧化1,2-丙二醇制备乳酸工艺进行了尝试性研究。制备了Cu/C、Pd/C负载型金属催化剂;考察了负载型金属催化剂的含量对目标反应产物催化性能的影响,证实了Pd/C催化剂比Cu/C催化剂具有更佳催化性能。研究了单因素(反应温度、氧气分压、反应时间)对氧化工艺的影响,讨论了各单因素对反应的影响情况。     

PBXN-5装药侵彻混凝土过载力学响应的试验研究

采用弹载小尺寸PBXN-5装药和加速度传感器,并以相同初始速度侵彻两种不同强度混凝土靶板,获得弹体侵彻的过载数据,通过对比分析侵彻前后装药试样的细观结构和外部形状的变化,研究了装药在不同过载条件下的动态力学特性.结果表明,弹内装药着靶后发生了外形镦粗、密度降低的现象,随着过载峰值的提高这一变化更为明显;装药内部出现了沿...     

TADFIW水解反应机理的密度泛函理论

应用密度泛函理论(DFT)在B3LYP/6-31G(d,p)水平下对四乙酰基二甲酰基六氮杂异伍兹烷(TADFIW)甲酰基的水解反应机理进行了研究.结果表明,TADFIW上的甲酰基水解时,甲酰基被质子化,碳氧双键中的氧原子带有负电荷0.619 e,碳原子带有正电荷0.471 e,亲核试剂水分子进攻质子化甲酰基的碳原子,同...     

Proton abstraction ability of MgO: a DFT cluster model study of the role of surface geometry

Methanol and isocyanic acid adsorptions on a defective MgO surface have been studied. Equilibrium geometries, adsorption energies, atomic and molecular charges and electronic densities were obtained using a density functional theory method. Oxide surface atoms with different coordination numbers show very different reactivity giving both molecular and dissociated adsorbed species. The methanol molecule requires lower coordination numbers of the active site than the isocyanic acid molecule for dissociative adsorption. The role of the acidic and basic sites has been considered and analyzed in terms of natural bond orbital charges. The main vibration frequencies have been compared with available infrared spectroscopic data.