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1.
利用紫外光谱和红外光谱研究了十二羰基三铁和十二羰基三钌分别与二苯基乙炔和三苯基膦的配位取代反应。谱图数据揭示出原始物质消失和新物质形成过程,并对结果产物作了压片红外光谱测定,进一步证实了新物质的生成。  相似文献   

2.
采用密度泛函UB3LYP/6–311+G(2d)方法计算研究了Fe+在基态和激发态与CO与N2O反应的反应机理。全参数优化了反应势能面上各驻点的几何构型,用频率分析方法和内禀反应坐标(IRC)方法对过渡态进行了验证,并用UB3LYP/6–311++G(3df,3pd)、单点垂直激发等方法分别进行各驻点单点能校正,四重态和六重态反应势能面交叉点CP确定,计算结果表明,该反应为两步反应,且反应机理都为插入—消去反应,势能面上的两个交叉点能够有效的降低反应的活化能,这在动力学和热力学上都是有利的。  相似文献   

3.
用密度泛函方法在UB3LYP/6-311G++(d,p)理论水平上研究了Ni+在基态与CH3CH2CH2NH2的反应机理,全参数优化了[Ni,C3,N,H9]+基态势能面上各驻点的几何构型,并用频率分析方法和内禀反应坐标(IRC)方法对过渡态进行了验证。结果表明第一过渡金属离子Ni+与CH3CH2CH2NH2的反应为插入-消去机理,并计算找到了基态下该反应的最有利通道。  相似文献   

4.
采用密度泛函理论的B3LYP方法,在6-311 G(d,p)基组水平上研究了CH2F自由基与HNCO的微观反应机理,优化了反应过程中的反应物、中间体、过渡态和产物的几何构型,通过振动分析验证了所有可能的过渡态;并且还在QCISD(T)/6- 311 G**//B3LYP/6-311 G(d,p)机组水平上计算了相应单点能.找到了CH2F自由基与HNCO反应的7条可行的反应通道,对结果的分析表明,CH2F HNCO→TS8→IM5→TS9→IM4通道的控制步骤活化能最低,是该反应的主要通道.  相似文献   

5.
The initial stage of the reaction between ozone and hexafluoropropylene (HFP) was studied by the DFT/B3LYP quantum-chemical method using the family of 6-31G basis sets and the cc-pVDZ+ basis set. Two reaction paths were compared, concerted (the Criegee mechanism) and nonconcerted (the DeMore mechanism) addition. For both reaction paths, the geometry and transition state energies, entropy, and thermodynamic and electronic enthalpy were calculated and the rate constants of the reaction were estimated. It was shown that the DeMore mechanism should be given preference for the reaction of HFP with ozone. UB3LYP calculations for the DeMore mechanism give reaction rate constants close to the experimental values.  相似文献   

6.
Hongjiang Ren 《Molecular physics》2013,111(23):3663-3672
The mechanism of H abstraction reactions for Isoflurane with the OH radical was investigated using density functional theory and G3(MP2) duel theory methods. The geometrical structures of all the species were fully optimised at B3LYP/6-311++G** level of theory. Thermochemistry data were obtained by utilising the high accurate model chemistry method G3(MP2) combined with the standard statistical thermodynamic calculations. Gibbs free energies were used for the reaction channels analysis. All the reaction channels were confirmed throughout the intrinsic reaction coordinate analysis. The results show that two channels were obtained, which correspond to P(1) and P(2) with the respective activation barriers of 63.03 and 54.82 kJ/mol. The rate constants for the two channels over a wide temperature range of 298.15–2000 K were predicted and the calculated data are in agreement with the experimental one. The results show that P(2) is the dominant reaction channel under 800 K and above 800 K, it can be found that P(1) will be more preferable reaction channel.  相似文献   

7.
以Ti(SO4)2和Zn(NO3)2·6H2O为原料,碳酸铵为沉淀剂,采用直接沉淀法制备了钛酸锌的粉体。探讨了反应条件对所得钛酸锌晶体结构的影响,并对样品进行了XRD和TG-DTA等分析。钛酸与碳酸锌分子生成的先后顺序影响得到的钛酸锌的结构。在钛酸优先生成的体系中,碳酸锌分子生成之后与周围足量的钛酸分子发生碰撞反应,由于钛酸优先生成且沉淀剂足量,碰撞反应充分且在碰撞反应中钛酸保持过量,反应生成了亚钛酸锌(Zn2Ti3O8)。在碳酸锌优先生成的体系中,钛酸分子生成之后与周围足量的碳酸锌分子发生碰撞反应,由于碳酸锌优先生成且沉淀剂足量,碰撞反应充分且在碰撞反应中碳酸锌保持过量,反应生成了正钛酸锌(Zn2TiO4)。另外,沉淀剂用量和反应温度都影响着最终产物的种类和晶型。沉淀剂用量越多、反应温度越高,越易于生成Zn2Ti3O8或Zn2TiO4。只有在沉淀剂不足、反应温度较低的情况下,才能生成偏钛酸锌(ZnTiO3)。  相似文献   

8.
在CH2 Cl2 介质中研究了铁 (Ⅱ )异腈配合物 [FeL5(CN) ]Br(1 ,L = CNCH2 Ph)和trans [FeL4(CN) 2 ] (2 ,L = CNCH2 Ph)等与氧原子转移试剂 (CH3) 3NO的反应动力学行为 ,研究结果表明 :配合物 1与 (CH3) 3NO反应遵从二级速率定律 ,反应速率 =k2 [铁异腈配合物 ]× [(CH3) 3NO]。反应的活化熵ΔS≠ 和活化焓ΔH≠ 分别为- 2 5 34± 1 67cal·(mol·K) - 1 和 1 2 71± 0 49kcal·mol- 1 ,而配合物 2不与氧原子转移试剂反应。认为反应以缔合机理进行。  相似文献   

9.
CX2(X=F, Cl, Br)与CH3CHO中C-C键插入和环加成的理论模拟   总被引:1,自引:1,他引:0  
采用密度泛函[DFT]和自然键轨道理论[NBO]及高级电子耦合簇[CCSD(T)]和电子密度拓扑分析[AIM]方法, 研究了单重态二卤卡宾CX2(X=F, Cl, Br)与乙醛CH3CHO 中C—C键的插入反应及其环加成的反应机理. 在B3LYP/6-31G(d)水平上优化了各驻点构型, 用频率分析和内禀反应坐标法(IRC)对过渡态进行了验证, 计算了各物种的CCSD(T)/6-31G(d, p)单点能量. 用经Wigner校正的Eyring过渡态理论分别计算了1大气压下主反应通道的热力学与动力学性质, 并对反应通道中构型进行了自然键轨道及电子密度拓扑分析. 结果表明, CF2与CH3CHO反应的主产物是P2F[CH3CF2CHO: 插入CH3CHO中C-C键, 反应I(2)], 而CCl2及CBr2与CH3CHO反应的主产物是P1Cl[Cl2COCHCH3: 成环反应II(1)]及P1Br[Br2COCHCH3: 成环反应III(1)], 1大气压下, 反应I(2)和II(1)及III(1)进行的适宜温度范围分别为400~1300K和400~1000K.  相似文献   

10.
The γ-decays of the states in 47Ti at 157 keV and 1547 keV have been studied following the 46Ti(d, p)47Ti reaction at 5.0 MeV incident energy. Protons were detected at 0° with a semiconductor detector. The angular correlations of the γ-rays with the reaction protons were measured. The E2/M1 mixing ratios of the γ-decays and the population ratios of the to the substates were deduced. From the non-zero population of the substate it was concluded that a spin-flip mechanism exists in the 46Ti(d, p)47Ti stripping reaction.  相似文献   

11.
研究了5(4-缬氨酸丁氧苯基)-10,15,20-三(4-氯苯基)卟啉锌与嘧啶在氯仿溶液中轴配反应光谱和热力学性质。用紫外-可见分光光度法测定了轴向配位反应体系的配位数和平衡常数。用温度系数法求得了轴配反应的标准摩尔焓变和标准摩尔熵变。探讨了温度对轴向配位反应的影响。  相似文献   

12.
2-氨基吡啶气相氟代反应的密度泛函理论研究   总被引:3,自引:1,他引:2  
采用量子化学方法,运用密度泛函理论(DFT)B3LYP方法,在6-311G*基组水平上,以2-氨基吡啶为起始反应物,全优化计算了亚硝酰阳离子NO~+对2-氨基吡啶中氨基进攻的重氮化反应及氟硼酸根阴离子BF_4~-对吡啶重氮正离子进攻的席曼反应的机理,搜索到整个反应过程中的过渡态结构,得到了反应路径并通过IRC验证,并对各反应中间体、过渡态和产物进行分子几何构型优化、振动频率分析和标准热力学函数计算.通过计算,搜索到的过渡态均为环状结构,与配位插入反应类似,利于原子间化学键的断裂及新键的形成;通过热力学及动力学计算,重氮化-席曼反应是剧烈的放热反应,与实验结果相吻合.  相似文献   

13.
The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the acetic acid to convert to acetone and methane in different temperatures. The results indicate that the sequence of the ketonization reaction activity for the clusters was [V3OAT] > [VFe2OAT], [V2CrOAT] > [Fe3OAT], [VCr2OAT] > [Cr3OAT] [OAT = (mu 3-O) (mu-O2CCH3)6 (THF)3], and the sequence of the methanation reaction activity for the clusters was [Cr3OAT] > [VCr2OAT], [V2CrOAT] > [V3OAT] > [VFe2OAT], [Fe2OAH]. The ketonization reaction activity of [Fe3OAT] were obviously lower than that of [Fe3OAH] [OAH = (mu 3-O) (mu-O2CCH3)6 (H2O)3] and the methanation reaction activity of [Cr3OAT] were also much lower than that of [Cr3OAH]. The difference between [Fe3OAH], [Cr3OAT] and [Fe3OAH], [Cr3OAH] mentioned above were discussed.  相似文献   

14.
采用量子化学方法,运用密度泛函理论(DFT)B3LYP方法,在6-311G*基组水平上,以2-氨基吡啶为起始反应物,全优化计算了亚硝酰阳离子NO+对2-氨基吡啶中氨基进攻的重氮化反应及氟硼酸根阴离子BF4-对吡啶重氮正离子进攻的席曼反应的机理,搜索到整个反应过程中的过渡态结构,得到了反应路径并通过IRC验证,并对各反应中间体、过渡态和产物进行分子几何构型优化、振动频率分析和标准热力学函数计算.通过计算,搜索到的过渡态均为环状结构,与配位插入反应类似,利于原子间化学键的断裂及新键的形成;通过热力学及动力学计算,重氮化-席曼反应是剧烈的放热反应,与实验结果相吻合.  相似文献   

15.
Colemanite is one of the most important boron minerals used for production of boric acid. Boric acid (H(3)BO(3)) is produced by the reaction of colemanite (2CaO.3B(2)O(3).5H(2)O) with sulfuric acid in a heterogeneous solid-liquid reaction leading to crystallization of gypsum as a byproduct.The influence of ultrasound on the dissolution of colemanite in H(2)SO(4) solution and on the precipitation of the gypsum during the reaction was investigated. Experiments have been carried out in a batch stirred vessel at 85 degrees C in the absence and presence of ultrasound. The stirring rates were chosen as 600 rpm (for 500-600 microm) and 800 rpm (for 1000-1180 microm) to provide a homogeneous suspension during the reaction. The boric acid and calcium ion concentrations in the solution were determined as a function of time. The results showed that ultrasound enhances the dissolution of colemanite and precipitation rate of the gypsum in the solution after 1h. It has been shown that the use of ultrasound decreases the size of gypsum crystals.  相似文献   

16.
采用密度泛函理论(DFT)中的B3LYP方法研究了二重态和四重态Pt+与甲烷反应的机理。通过几何构型优化和频率计算,分别获得三个过渡态,并利用内禀反应坐标(IRC)计算进行了验证。在更高的基组水平上计算了单点能,并详细讨论了二重态和四重态的势能面。结果表明在二重态势能面上的反应具有比较低的能垒,是一个放热反应,所以该反应更易于在二重态上进行。氧化加成生成中间体HPt(CH3)+的步骤需要克服一个小小的能垒。  相似文献   

17.
在B3LYP/6-311+G(d,p)和QCISD(T)/6-311++G(d,p) 水平上,对气相中铝与水的反应进行了计算. 理论计算结果表明,铝水反应经过了三条可能的反应通道并且涉及了四个异构体、七个过渡态和两种产物. 其中两条反应通道所涉及的中间物和产物已被实验测得. 同时,在298 K和2000 K计算了铝水反应的焓变和吉布斯自由能,一些计算结果与以前的计算和实验结果吻合较好.  相似文献   

18.
在CCSD(T)/6-311g(d,p)/B3LYP/6-311g(d,p)的基础上对F原子与反式的1,3-丁二烯的反应体系进行了理论研究.计算中发现,这个反应体系有两个形成中间复合物的通道.同时,理论计算结果表明,在交叉分子束的实验中探测到的H原子是通过这两个形成长寿命的中间复合物的通道产生的.而通过同一个复合物通道,生成C2H3 C2H3F的速率要比生成氢原子的低,在交叉分子束实验中要探测到C2H3 C2H3F通道也是很困难的.理论分析的结果还表明, HF也可能是反应中的一个产物,它主要是通过直接抽取反应产生的.  相似文献   

19.
In the standard Big Bang nucleosynthesis(SBBN) model, the lithium puzzle has attracted intense interest over the past few decades, but still has not been solved. Conventionally, the approach is to include more reactions flowing into or out of lithium, and study the potential effects of those reactions which were not previously considered.~7Be(d,~3He)~6Li is a reaction that not only produces~6Li but also destroys~7Be, which decays to~7Li, thereby affecting~7Li indirectly. Therefore, this reaction could alleviate the lithium discrepancy if its reaction rate is sufficiently high.However, there is not much information available about the~7Be(d,~3He)~6Li reaction rate. In this work, the angular distributions of the~7Be(d,~3He)~6Li reaction are measured at the center of mass energies Ecm = 4.0 Me V and 6.~7Me V with secondary~7Be beams for the first time. The excitation function of the~7Be(d,~3He)~6Li reaction is first calculated with the computer code TALYS and then normalized to the experimental data, then its reaction rate is deduced. A SBBN network calculation is performed to investigate its influence on the~6Li and~7Li abundances. The results show that the~7Be(d,~3He)~6Li reaction has a minimal effect on~6Li and~7Li because of its small reaction rate. Therefore,the~7Be(d,~3He)~6Li reaction is ruled out by this experiment as a means of alleviating the lithium discrepancy.  相似文献   

20.
利用固体核磁共振方法,研究了铜修饰丝光沸石(Cu-H-MOR)分子筛催化甲醇(CH3OH)与一氧化碳(CO)羰基化反应过程.通过研究反应过程中生成的各吸附物种与Cu2+的相互作用,分别对这些吸附物种进行了归属,确定了铜甲氧基(Cu-OCH3)和铜乙酰基(Cu-(CO)-CH3)为羰基化反应过程的中间产物,讨论了可能的反应机理.  相似文献   

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