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1.
O(3P)+O2H→OH+O2反应机理的密度泛函理论研究   总被引:4,自引:3,他引:1  
用密度泛函理论方法研究了O(3P)与O2H反应生成羟基和氧分子的反应机理. 在PW91/6-31+G水平上用梯度解析技术全自由度优化上述反应物、产物和反应路径上的中间体及过渡态几何构型, 并通过频率振动分析加以确认, 计算IRC反应路径及中间体异构化过程, 确定了此反应的可能反应通道. 结果表明: 该反应是多通道多步骤的强放热反应. 首先形成顺式或反式O3H富能中间体, 此过程无能垒; 然后跨过一个能垒分解成产物OH和O2. 通道IM1→TS1比IM2→TS2克服的能垒要大, 反应放热372.822 kJ*mol-1. IM1TS3IM2 可相互转化.  相似文献   

2.
应用密度泛函理论研究了反应通道(a)C2H3+NO→CH3+NCO和(b)C2H3+NO→OH+C2H2N的反应机理.在B3LYP/6-31G(d)水平上优化了反应物、中间体、过滤态、产物的几何构型,通过频率分析确定了11个中间体和10个过渡态.所有的反应物、中间体、过渡态、产物都在CCSD/6-311++G(d,p)水平上进行了单点能较正.并讨论了反应的异构化过程.计算结果表明10是能量最低的中间体,比反应物的能量低308 479kJ/mol;过渡态1/3,2/5,3/4,4/8比反应物的能量高,其中3/4是能量最高的过渡态,比反应物的能量高91 894kJ/mol.通道(a)和(b)的理论放热值分别为111 059和96 619kJ/mol.  相似文献   

3.
OH+ C2H2N←C2H3 + NO→CH3 + NCO反应机理的密度泛函理论研究   总被引:2,自引:1,他引:1  
应用密度泛函理论研究了反应通道(a)C2H3 NO→CH3 NCO和(b)C2H3 NO→OH C2H2N的反应机理.在B3LYP/6-31G(d)水平上优化了反应物、中间体、过滤态、产物的几何构型,通过频率分析确定了11个中间体和10个过渡态.所有的反应物、中间体、过渡态、产物都在CCSD/6-311 G(d,P)水平上进行了单点能较正.并讨论了反应的异构化过程.计算结果表明10是能量最低的中间体,比反应物的能量低308.479kJ/mol;过渡态1/3,2/5,3/4,4/8比反应物的能量高,其中3/4是能量最高的过渡态,比反应物的能量高91.894kJ/mol.通道(a)和(b)的理论放热值分别为111.059和96.619kJ/mol.  相似文献   

4.
用密度泛函理论方法研究了 O( 3P)与 O2 H反应生成羟基和氧分子的反应机理 .在 PW91 /6-31 +G*水平上用梯度解析技术全自由度优化上述反应物、产物和反应路径上的中间体及过渡态几何构型 ,并通过频率振动分析加以确认 ,计算 IRC反应路径及中间体异构化过程 ,确定了此反应的可能反应通道 .结果表明 :该反应是多通道多步骤的强放热反应 .首先形成顺式或反式 O3H富能中间体 ,此过程无能垒 ;然后跨过一个能垒分解成产物 OH和 O2 .通道 IM1→ TS1比 IM2→ TS2克服的能垒要大 ,反应放热 372 .82 2 k J.mol- 1 .IM1 TS3 IM2可相互转化  相似文献   

5.
采用密度泛函方法B3LYP/6-311+G(d, p)和耦合簇方法CCSD/6-311+G(d, p)研究了BH2+与H2O的气相离子-分子反应机理. 优化得到了反应途径中各驻点的几何构型, 并采用内禀反应坐标法进行追踪. 从量子拓扑学的角度, 讨论了在反应过程中各化学键的变化. 反应(I)经历了一个四元环过渡态, 找到了这个反应的能量过渡态和两个结构过渡态.  相似文献   

6.
CH3O2·+ClO气相反应的密度泛函理论研究   总被引:2,自引:1,他引:1  
用密度泛函方法在CCSD(T)/ 6-311++G// B3LYP/ 6-311G**水平上研究了气相反应CH3O2*+ClO的反应机理.得到了不同能量产物的可能的反应通道,获得反应势能面.整个反应过程为多通道反应,经过多个步骤完成,共找到7个中间体和10个过渡态,产物1CH3OCl+3O2(P1)和1 CH2O+1HOOCl(P4)为能量较低产物,通道1a:R→IM1→TS1/ 3→IM3→P1,4a:R→IM1→TS1/ P4→P4和4b:R→IM2→TS2/ P4→P4为较为可行的反应通道.  相似文献   

7.
OBrO+NO反应机理的量子化学研究   总被引:3,自引:0,他引:3  
用密度泛函B3LYP/6-311+G**和高级电子相关偶合簇CCSD(T)/6-311+G**方法研究了OBrO与NO反应的微观机理.优化得到反应路径上的反应物、过渡态、中间体和产物的几何构型,通过频率振动分析对过渡态和中间体进行了确认.结果表明;该反应是多通道多步骤的放热反应,分别可以在单重态和三重态势能面上进行,OBrO与NO通过加成及加成-消除机理分别形成产物BrONO2和BrO+NO2,从能量上看,形成离解产物的通道更容易进行.  相似文献   

8.
用从头算UHF/6-31G基组研究了异氰酸和羟基生成氨基和二氧化碳即HNCO+OH→NH2+CO2的反应机理.优化得到了反应途径上的过渡态和中间体,并通过振动分析对过渡态和中间体进行了确认.在UMP4/6-31G水平上计算了它们的能量,同时对零点能进行了较正.计算结果表明:此反应是多步反应,先后通过3个过渡态(TS1,TS2,TS3),2个内旋转位垒(PSI,TSII),4个中间体(IM1,IM2,IM3,IM4),其中,IM3→TS2这一步为整个反应的决速步骤,速控步的活化能为202.388lJ/mol.与异氰酸和羟基作用的另一反应通道(即HNCO+OH→H2O+NCO)的活化能(69.038kJ/mol)比较,可看出所研究反应通道为次要反应通道,这与实验结果是一致的.  相似文献   

9.
F~2+2HCl→2HF+Cl~2反应机理的密度泛函理论研究   总被引:6,自引:0,他引:6  
用密度泛函理论(DFT)B3LYP方法,在6-311G^*^*基组下,计算研究了反应F~2+2HCl→2HF+Cl~2的机理。求得各可能反应途径的系列过渡态,并通过振动分析和内禀反应坐标(IRC)分析加以证实。比较反应能垒(理论计算活化能)发现,标题反应若以分子与分子作用机理进行,则需克服的最大能垒为150.63kJ.mol^-^1;若以F~2分子先裂解为F原子再反应的机理进行,则需越过能垒154.82kJ.mol^-^1,求得反应F+HCl→HF+Cl的线形和三角形两种过渡态,以三角形较稳定;求得反应HCl+Cl→H+Cl~2的两种过渡态,以线形较稳定。  相似文献   

10.
1CH2+N2O反应的势能面   总被引:2,自引:0,他引:2  
利用密度泛函理论(B3LYP)计算了1CH2+N2O反应的反应物、中间体、过渡态及产物 的几何构型.进而用从头算方法(QCISD(T))计算了单点能量.由此描绘了反应的势能面, 确定了反应的最终产物通道为N2+H2CO和NO+HCN+H.后者比前者有更大的分支比.N2、H2CO 、NO、HCN的存在有待于实验检测.作者认为,反应在室温下是加成-消除机理,而在高温下 可以通过直接取代的机理获得N2+H2CO.  相似文献   

11.
12.
Speeds of sound, u, have been measured as a function of concentration for the systems, CaSO4·2H2O +CaCl2 + H2O and CaSO4·2H2O + NaCl + H2O, at temperatures of 30 and 35 °C. Derived parameters such as the isentropic compressibility, κ S , and the shear relaxation time,τ,were calculated using the experimental speed of sound data in combination with viscosity values from our earlier work. Results have been compared with those of the CaCl2+ H2Oand NaCl + H2O systems reported in literature,to examine the effect of adding CaSO4·2H2O(s).Values of κ S for the system,CaSO4·2H2O + CaCl2+H2O,are smaller compared with those for the CaCl2+ H2O system.Values of τ are lower at lower concentrations and then cross over in a narrow concentration region.Values of κ S for the system,CaSO4·2H2O+NaCl+H2O, are also smaller when compared with those forthe NaCl +H2O system.For this system the τ values are higher. These τ values reach a minimum at a certain concentration of NaCl in the solution and then increase with further increases in concentration.The influenceof solvent-separated and/or solvent-shared ion pairs plays a dominant role at higher concentrations for both systems.Results have been interpreted and discussed in terms of the expansion and contraction of the primary hydration shell of the ionic species present in the studied systems.  相似文献   

13.
14.
Intermolecular potential energy curves for the hydrogen bonded systems H2O·H2S, H2O·H2Se and H2S·H2S were calculated with nonempirical pseudopotentials using optimized-in-molecules basis sets augmented by polarization functions. The H2O·H2O interaction energy curve has been also considered as a test case. The present results for H2O·H2S and H2S·H2S indicate much weaker intermolecular interactions than those found in previous ab initio calculations. The H2O·H2Se interaction was found to be quite similar to H2O·H2S.This work was partly supported by the Polish Academy of Sciences within the Project PAN-09, 7.1.1.1On leave from Quantum Chemistry Laboratory, Dept. of Chemistry, University of Warsaw, Pasteura 1, 02-093. Warsaw, Poland  相似文献   

15.
包结物[H2(teta)]2+·2Cl-·3H2O的合成与结构研究   总被引:2,自引:0,他引:2  
大环化合物在生命和材料科学中很重要[1,2]。大环四胺配体5,7,7,12,14,14 六甲基 1,4,8,11 四氮杂环十四烷(teta)近年来引起了广泛关注[3,4]。我们合成了化合物[H2(teta)]2+·2Cl-·3H2O,测定了晶体结构。1 实验部分1.1 [H2(teta)]2+·2Cl-·3H2O的合成[5]将5mL0 4mmolHCl水溶液缓慢加入teta·2H2O(0 0641g,0 2mmol)的5mL甲醇溶液。连续搅拌半小时后过滤,无色滤液在室温下放置两天后长出淡黄色块状晶体。元素分析(计算值)%:C,47 58(46 71);H,10 53(10 78);N,13 68(13 62).IR(cm 1):3331(vs),3231(s),3186(vs),2973(s),2876(s)…  相似文献   

16.
Oxatriquinanes are tricyclic oxonium ions which are known to possess remarkable solvolytic stability compared to simple alkyl oxonium salts. Their rigid, hemispherical structure presents an oxygen at the apex of three fused five-membered rings. While trivalent oxygen species like these have been well described in the literature, the ability of oxygen to enter into a fourth covalent bonding relationship has been visited in theory and suggested by the outcome of certain reactions conducted in superacidic media, but has never been established by the characterization of a stable, persistent R(3)OH(2+) or R(4)O(2+) ion. In this study, the nucleophilicity of the oxatriquinane oxygen was evaluated first by a series of protonation studies using the Br?nsted superacid H(CHB(11)Cl(11)) both in the solid state and in liquid HCl solution. The interaction of the oxatriquinane oxygen with a bridging carbocation was also examined. A strong case could be made for the occurrence of hydrogen bonding between H(CHB(11)Cl(11)) and oxatriquinane using IR spectroscopy. Under the most forcing protonation conditions, the oxatriquinane ring is cleaved to give a bridged, dicationic, protonated tetrahydrofuran-carbenium ion.  相似文献   

17.
A pure phase of monosodium aluminate hydrate Na2O · Al2O3 · 2.5H2O (MAH) is synthesized and characterized by means of XRD, IR, SEM, TGA, and DSC. The heat capacity of the compound is measured in the temperature range of ?100 to 100°C, and the thermal contributions to enthalpy and entropy are calculated. The standard entropy, enthalpy, and Gibbs energy of formation of MAH at 298 K are estimated.  相似文献   

18.
The energy, the Gibbs energy of the reaction OH-·(H2O) n- 1 + H2O = OH-·(H2O) n are calculated by the Monte-Carlo method with a large canonical ensemble for n = 1, ..., 20. The ion-waternonpair interaction potential was obtained by numerical fitting of calculated Gibbs energy and entropy of (H2O)n clusters (n = 1, ..., 5) to experimental ones. A good fit to experiment both of the internal energy and the Gibbs energy can be obtained in terms of a model allowing for nonpair interaction. It is shown that constructing an ion-water interaction potential without allowance for the entropy factor can lead to considerable errors in the Gibbs energy of cluster formation and in the nucleation rate.  相似文献   

19.
Two pure zinc borates with microporous structure 3ZnO·3B2O3·3.5H2O and 6ZnO·5B2O3·3H2O have been synthesized and characterized by XRD, FT-IR, TG techniques and chemical analysis. The molar enthalpies of solution of 3ZnO·3B2O3·3.5H2O(s) and 6ZnO·5B2O3·3H2O(s) in 1 mol · dm−3 HCl(aq) were measured by microcalorimeter at T = 298.15 K, respectively. The molar enthalpies of solution of ZnO(s) in the mixture solvent of 2.00 cm3 of 1 mol · dm−3 HCl(aq) in which 5.30 mg of H3BO3 were added were also measured. With the incorporation of the previously determined enthalpy of solution of H3BO3(s) in 1 mol · dm−3 HCl(aq), together with the use of the standard molar enthalpies of formation for ZnO(s), H3BO3(s), and H2O(l), the standard molar enthalpies of formation of −(6115.3 ± 5.0) kJ · mol−1 for 3ZnO·3B2O3·3.5H2O and −(9606.6 ± 8.5) kJ · mol−1 for 6ZnO·5B2O3·3H2O at T = 298.15 K were obtained on the basis of the appropriate thermochemical cycles.  相似文献   

20.
The direct measurements of differential enthalpies of solution Δsol H 2, of LiCl·H2O, NaCl, KCl, MgCl2·6H2O, CaCl2·6H2O and BaCl2·2H2O, as the function of molality,m, in the region of concentrated solutions were performed. On this basis the enthalpies of crystallization, Δcryst H m, were calculated and compared to the appropriate literature data.  相似文献   

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