2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面的裂解机理

本文研究了2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面解离的可能微观反应机理,使用完全线性同步和二次同步变换(complete LST/QST)方法确定解离反应的过渡态.采用基于第一性原理的密度泛函理论与周期平板模型相结合的方法,优化了2-丙醇和1,1,1-三氟-2-丙醇裂解反应过程各物种在Ni(100)表面的top,hollow和bridge位的吸附模型,计算了能量,并对布局电荷进行了分析,得到了各物种的有利吸附位.结果表明:2-丙醇和1,1,1-三氟-2-丙醇在Ni(100)表面都存在β-H和γ-H两个平行竞争的解离过程,其中2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为64.7 k J·mol-1猯,而γ-H解离速控步骤活化能为233.1 k J·mol-1猯,故β-H解离过程占优势,主要产物是CH3COCH3;相反,1,1,1-三氟-2-丙醇在Ni(100)表面β-H解离的速控步骤活化能为257.1 k J·mol-1猯,而γ-H解离速控步骤活化能为148.1 k J·mol-1猯,故γ-H解离过程占优势,主要产物是CF3CH=CH2.由此说明,电负性更大的氟原子取代2-丙醇中的氢原子之后,2-丙醇在Ni表面的解离机理发生了改变.理论预测结果与实验结论一致.     

CHx(x=2~4)在Fe(110)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法,对物种CHx(x=2~4)在Fe(110)表面的top,hcp,SB和LB位的吸附模型进行了结构优化、能量计算,得到了各物种较有利的吸附位;并对最佳吸附位进行密立根电荷和总态密度分析。结果表明：CH4在Fe(110)表面的最稳定吸附位都是SB位,吸附能别是-38.14 kJ•mol-1,CH3在Fe(110)表面的最稳定吸附位都是top位,吸附能别是-171.78 kJ•mol-1,而CH2在Fe(110)表面的最稳定吸附位hcp的吸附能是-342.43 kJ•mol-1;CH3 和CH2两物种与金属表面成键,属于化学吸附。     

CHx(x=2~4)在Fe(110)表面吸附的DFT研究

采用密度泛函理论与周期平板模型相结合的方法,对物种CHx(x=2~4)在Fe(110)表面的top,hcp,SB和LB位的吸附模型进行了结构优化、能量计算,得到了各物种较有利的吸附位;并对最佳吸附位进行密立根电荷和总态密度分析。结果表明：CH4在Fe(110)表面的最稳定吸附位都是SB位,吸附能别是-38.14 kJ•mol-1,CH3在Fe(110)表面的最稳定吸附位都是top位,吸附能别是-171.78 kJ•mol-1,而CH2在Fe(110)表面的最稳定吸附位hcp的吸附能是-342.43 kJ•mol-1;CH3 和CH2两物种与金属表面成键,属于化学吸附。     

2-甲基-1,3-顺丁二烯在Ni (I)催化下与苯甲醛反应机理的研究

采用密度泛函理论（DFT）研究了2-甲基-1,3-顺丁二烯在Ni(I)催化下与苯甲醛反应生成高烯丙基醇的反应机理。在B3LYP/6-31+G*水平上对反应过程中所有反应物、过渡态、中间体以及产物的几何构型进行了优化,通过能量和振动分析确认了过渡态的真实性;并且在相同基组水平上应用自然键轨道(NBO)和分子中的原子(AIM)理论分析了这些化合物的成键特征和轨道间的相互作用。研究发现了两条可能的反应通道IA与IB,其控制步骤活化能分别为64.20 kJ.mol-1、51.63 kJ.mol-1,由以上比较结果可以看出,反应通道IA与IB在整个反应过程可能同时发生,但IB通道具有较低的活化能,即IB通道为整个反应的最优反应通道,与实验结果一致。     

理论研究F2BN3多聚体的结构特色和热力学稳定性

在密度泛函理论（DFT）B3LYP/6-311+G*水平上计算研究了叠氮二氟硼多聚体(F2BN3)n (n=1-4),获得了它们的结构和热力学性质,讨论了几何参数随聚合度的变化趋势。多聚体(F2BN3)2-4的优化构型均为由不同子体系的叠氮基α−N和B原子相连形成的环状结构。三聚体的船扭式构象比椅式构象的结合能低10.54 kJ•mol-1;四个新获得的四聚体的结合能差异较大,大小为3.1~45.65 kJ•mol-1。由焓变可知,单体形成二聚体在热力学上是不利的,而形成三聚体和四聚体在高达1200 K的温度下是有利的,同时分析比较了后续反应的热力学参数。     

2-甲基-1,3-顺丁二烯在Ni(Ⅰ)催化下与苯甲醛反应机理的研究

采用密度泛函理论(DFT)研究了2-甲基-1,3-顺丁二烯在Ni(I)催化下与苯甲醛反应生成高烯丙基醇的反应机理.在B3LYP/6-31+G*水平上对反应过程中所有反应物、过渡态、中间体以及产物的几何构型进行了优化,通过能量和振动分析确认了过渡态的真实性；并且在相同基组水平上应用自然键轨道(NBO)和分子中的原子(AIM)理论分析了这些化合物的成键特征和轨道间的相互作用.研究发现了两条可能的反应通道IA与IB,其控制步骤活化能分别为64.20 kJ·mol-1、51.63 kJ·mol-1,由以上比较结果可以看出,反应通道IA与IB在整个反应过程可能同时发生,但IB通道具有较低的活化能,即IB通道为整个反应的最优反应通道,与实验结果一致.     

CH3OH在Ga-Rich GaAs(001)-(4×2)表面上的吸附与解离: 团簇模型的密度泛函计算

采用简单团簇模型结合密度泛函理论研究了CH3OH在Ga-Rich GaAs(001)-(4×2)表面上的吸附与解离过程. 计算结果表明, CH3OH在Ga-Rich GaAs(001)-(4×2)表面上首先会形成两种化学吸附状态, 然后CH3OH经解离生成CH3O自由基和H原子吸附在表面不同位置上. 通过比较各个吸附解离路径, 发现解离后的H原子相对更容易吸附在位于表面第二层紧邻的As原子上.     

HCOOH在Pd-Fe(111)(nPd:nFe=1:1)表面吸附的密度泛函理论研究

采用密度泛函理论与周期性平板模型相结合的方法,对HCOOH在Pd(111)表面top, fcc, hcp, bridge 四个吸附位和Pd-Fe(111)表面Pd-top, Fe-top, PdPd-bridge, PdFe-bridge, FeFe-bridge, Pd2Fe-hcp, PdFe2-hcp, Pd2Fe –fcc, PdFe2-fcc等9个吸附位的13种吸附模型进行了能量计算、构型优化,得到了HCOOH较有利的吸附位;并对清洁表面进行能带分析。结果表明：掺杂Fe后,Pd催化剂对HCOOH催化活性增强;HCOOH在Pd(111)表面的最稳定吸附位fcc的吸附能是-41.8kJ•mol-1,在Pd-Fe(111)表面的最稳定吸附位Pd2Fe-hcp的吸附能是-126.5 kJ•mol-1,而且HCOOH在金属表面属于化学吸附。     

硫酸铵存在下碘化物-4-氨基安替吡啉-丙醇体系萃取分离镉1

研究了在硫酸铵存在下,碘化物-4-氨基安替吡啉体系萃取镉的行为以及丙醇水溶液的分相条件。实验表明,丙醇作为萃取溶剂能萃取中性离子缔合物。调节溶液pH=2.0—3.0,该体系能使Cd2 从常见过渡元素Fe~(2 )、Co~(2 )、Mn~(2 )、Ni~(2 )、Zn~(2 )的混合液中分离出来。     

碳纳米管及其H_2吸附体系的Raman光谱

利用紫外Raman光谱技术 ,对分别以CO和CH4为碳源、由化学催化法制备的两种多壁碳纳米管以及它们的H2 吸附体系进行Raman光谱表征 ,观测到可分别归属于类石墨结构的基频模G (1 5 80cm- 1 )和D (1 41 6cm- 1 ,缺陷诱导 ) ,以及它们的二阶和三阶组合频 2D(2 83 2cm- 1 ) ,D +G (2 996cm- 1 ) ,2G (3 1 6 0cm- 1 )和 2D +G (441 2cm- 1 )的Raman峰 ;H2在这些多壁碳纳米管上吸附有两种形式 :非解离吸附分子氢H2 (a)和解离吸附生成含氢表面物种CHX(x =3 ,2 ,1 ) ,所观测在 2 85 0 ,2 96 7和 3 95 0cm- 1 处的Raman谱峰可分别归属于表面CH2 基的对称C -H伸缩模 ,CH3基的不对称C -H伸缩模 ,以及吸附态分子氢H2 (a)的H -H伸缩模     

Excess isentropic compressibility and speed of sound of the ternary mixture 2-propanol + diethyl ether + n-hexane and the constituent binary mixtures at 298.15 K

Speed of sound and densities of the ternary mixture 2-propanol + diethyl ether + n-hexane and also the binary mixtures 2-propanol + diethyl ether and 2-propanol + n-hexane have been measured at the entire composition range at 298.15 K. The excess isentropic compressibilities and the excess speed of the sound have been calculated from experimental densities and speed of sound. These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka’s equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary mixtures and also the ternary mixtures. Speed of sound of the binary mixtures and the ternary mixture have been compared with calculated values from free length theory (FLT), collision factor theory (CFT), Nomoto’s relation (NR), Van Deal’s ideal mixing relation (IMR) and Junjie’s relation (JR). The results are used to compare the relative merits of these theories and relations in terms of the root mean square deviation relative (RMSD_r).     

从头算研究3-氨基-1-丙醇的电离能

采用MP2/6-311++G**方法研究了3-氨基-1-丙醇势能面上能量最低的14种构象. 运用B3LYP, MP3和MP4计算了构象的相对能量,结果说明含有分子内OH…N氢键的两种构象最稳定. 电子传播子理论的P3/aug-cc-pVTZ近似方法计算了构象的电离能,与光电子能谱的实验数据符合较好. 运用自然键轨道理论解释了构象间最外价壳层轨道电离能的差异. 结合统计力学原理,计算了不同温度下的构象分布,解释了光电子能谱依赖温度的原因.     

Methyl orbital signatures in 2-amino-1-propanol

Electron density distributions of 2-aminoethanol (2AE) and 2-amino-1-propanol (2AP) are calculated in both the coordinate and the momentum spaces using the B3LYP/TZVP method. Using the dual space analysis, molecular orbital signatures of the methyl substituent in 2AP are identified with respect to 2AE. Relaxations of the geometry and the valence orbital in 2AP are found to be due to the insertion of the methyl group. Five orbitals, not four orbitals, are identified as the methyl signatures. They are orbital 5a in the core shell, orbitals 9a and 10a in the inner valence shell, and orbitals 15a and 16a in the outer valence. In the inner valence shell, the attachment of methyl to 2AE causes a splitting of its orbital 8a into orbitals 9a and 10a of 2AP, whereas in the outer valence shell, the methyl group results in the insertion of an additional orbital pair of 15a and 16a. The frontier molecular orbitals 21a, 20a, and 19a are found to have no significant role in the methylation of 2AE.     

Molecular conformation and liquid structure of 2-propanol through neutron diffraction

The neutron diffraction data analysis of deuterated liquid 2-propanol at room temperature to define its molecular conformation is presented. 2-Propanol being a large molecule with twelve atomic sites, the conformation analysis is tricky and an improved method of data analysis is given. The intermolecular structural correlations, i.e., hydrogen-bonded liquid structure, can be modelled accurately to extract the nature of the average hydrogen-bonded molecular association in liquid state at room temperature. Like other alcohols these are mostly hexamer ring chain (HRC) clusters. The cluster analysis of recent X-ray data available in the literature also support the same liquid structure.     

ENDOR studies of alkyl substituted p-Benzosemiquinones in reversed micelles and in 2-propanol

Various substituted p-benzosemiquinone radical anions, inter alia ubisemiquinone and derivatives, have been investigated in 2-propanol and in reversed micelles by EPR and ENDOR spectroscopy. Unsymmetrical semiquinones, with respect to the oxygen atoms, experience remarkable hyperfine shifts depending on the medium. This effect even allows differentiation between stereoisomers. Immobilization of the semiquinone molecules at the water-surfactant interface in reversed micelles gives rise to pronounced asymmetric linewidth effects. In the case of 2-cyclohexyl-3-methyl-1,4-benzosemiquinones, mixtures of two species (conformers) have been observed.     

A field-dependent CIDNP study of the photochemical reduction of benzoquinones in 2-propanol

The CIDNP behaviour in the photochemical reduction of a series of 1,4-benzoquinones in 2-propanol was studied systematically in detail at low fields. The radical pair model formulated by Lawler and co-workers was extended to interpret the present results. It is of interest to note that the polarization crossover occurs at relatively high fields compared to other known systems and it is insensitive to the number of protons in the various quinones.     

Two-dimensional ordering in 1-propanol-graphite-oxide intercalates: isotopic effects

ABSTRACT

Intercalation of fully deuterated 1-propyl alcohol into graphite oxide is studied by means of the unique capabilities offered by the NIMROD neutron diffractometer. We develop methods to estimate the amount of intercalant present within the neutron irradiated volume using for the purpose of the set of constraints implicit in the outputs of the Gudrun diffraction data treatment software. The results are compared to those from our previous study on of fully hydrogenated 1-propanol intercalation [C. Cabrillo, F. Barroso-Bujans, R. Fernandez-Perea, F. Fernandez-Alonso, D. Bowron and F.J. Bermejo, Carbon 100, 546 (2016)] where a two-dimensional ordering transition under slow heating from 100?K was discovered. The rearrangement of the 1-propanol molecular pillars did allow for the formation of bilayer intercalation. In contrast, sample deuteration leads to remarkable differences in both the intercalation kinetics and intercalate thermal response, avoiding the two-dimensional transition which would lead to bilayer formation. Finally, neutron diffraction results have enabled us to disentangle the highly anomalous behaviour exhibited by hitherto unpublished broad band dielectric spectroscopy studies which are now understood on the basis of the two-dimensional transition just referred to.     

Ordered intermediate compound PtBi-modified Pt/C catalyst for 2-propanol electrooxidation in alkaline medium

The PtBi-modified Pt/C catalyst was prepared by liquid chemical reduction method. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) were used to characterize PtBi-modified Pt/C catalyst. The electrochemical behaviors for the 2-propanol electrooxidation reaction in alkaline medium were measured by cyclic voltammetry, line sweep voltammetry, and electrochemical impedance spectra (EIS). The results showed that the prepared PtBi is ordered intermediate compound. Compared with the spectrum obtained from Pt/C catalyst, the XPS peak of PtBi-modified Pt/C catalyst is obviously moving toward the low Pt 4f biding energy. The Bi⁰ and Bi₂O₃ coexist on the surface of PtBi/C catalyst. In alkaline medium, the electrochemical activity of 2-propanol electrooxidation of PtBi/C catalyst is higher than that of commercial Pt/C catalyst. EIS result shows that the reaction mechanism of 2-propanol electrooxidation for both catalysts is similar.     

On the equilibrium of peroxy radicals in the oxidation of 2-propanol by molecular oxygen

Based on kinetic data, it is demonstrated that the 1-hydroxy-1-methylethylperoxyl and hydroperoxy radicals are at equilibrium in the oxidation of 2-propanol at 323°C initiated by azobisisobutyronitrile. It is shown that the equilibrium of between the peroxy radicals is not disturbed within the covered range of alcohol concentrations. The rate constants of the reaction of the hydroperoxy radical with 2-propanol is determined: k _2.2 = (0.13 ± 0.04) L mol^?1 s^?1.