加入内标物求解二苯醚OH加合物生成速率常数

往二苯醚(C₁₂H₁₀O)-HNO₂体系中加入内标物苯(C₆H₆), 借助苯和二苯醚与•OH自由基之间的竞争反应, 分析355 nm激光闪光光解C₁₂H₁₀O-C₆H₆-HNO₂体系的衰减动力学曲线, 结合C₁₂H₁₀O-OH adduct的衰减速率常数逆推C₁₂H₁₀O-OH adduct的生成反应速率常数. 借助一种近似方法——微扰论, 通过对＞340 nm处衰减曲线的拟合, 得到C₁₂H₁₀O-OH adduct的生成速率常数为(1.8±0.8)×10¹⁰ L•mol^－1•s^－1.     

氟氯酰与丙烷反应的密度泛函理论研究

应用密度泛函理论(DFT), 对氟氯酰(ClF₃O)引发丙烷(C₃H₈)反应生成C₃H₇自由基或丙醇等产物的机理进行了研究. 在B3PW91/6-311＋＋G(d,p)水平上优化了9个不同反应通道上各驻点物(反应物、中间体、过渡态和产物)的几何构型, 并计算了它们的振动频率和零点振动能. 通过零点能校正计算了各反应路径的活化能, 并应用过渡态理论计算了各反应路径常温下的速率常数k. 计算结果表明: ClF₃O与C₃H₈反应可经过不同路径生成HF, C₃H₇自由基和C1F₂O自由基或C₃H₇OH和ClF₃. 其中, 最可几反应路径为ClF₃O分子的中间位F原子进攻丙烷β位H原子的反应, 活化能仅为7.54 kJ/mol, 速率常数为0.153×10⁶ mol^－1•dm³•s^－1.     

活性氮与碘乙烷反应化学发光研究

在流动余辉装置上, 利用N₂空心阴极放电制备活性氮, 研究了活性氮与碘乙烷(C₂H₅I)反应的化学发光. 在620～820 nm波长范围内观察到了较强的发射光谱, 拟合得到的光谱常数表明它来源于NI(b¹Σ^＋→X³Σ^－)跃迁, 并对35个谱峰进行了振动归属. 最后讨论了活性氮中主要成分与C₂H₅I反应的可能过程, 结合辅助性实验分析表明, 活性氮中的N(²P)与C₂H₅I直接反应很可能产生激发态NI(b¹Σ^＋)自由基. 这是利用化学反应直接产生激发态NI(b¹Σ^＋)的首次报道, 观察到的激发态最高振动能级为v'＝6.     

含硝基一代光致变色液晶树枝状大分子的光化学研究

研究了树外围含12个硝基偶氮苯基元新型一代碳硅烷光致变色液晶树枝状大分子G1和基元小分子M1在溶液中的最大吸收波长、摩尔消光系数、反-顺光化学异构化反应速率常数、热回复异构化反应速率常数、光化学回复异构化反应平衡常数及速率常数. G1的光致变色反应速率常数的数量级为10^－1 s^－1, 而含偶氮基元液晶聚硅氧烷的光致变色反应速率常数的数量级为10^－8 s^－1, 因此液晶树枝状大分子的光响应速率比后者快10⁷倍. G1的光回复异构化反应平衡常数k_t /k_c为1.76～1.77, 有作为光控开关材料的应用前景.     

乙腈溶液中NO3自由基与联苯的反应机理

以硝酸铈铵乙腈溶液激光闪光光解产生的NO₃自由基在无氧条件下与联苯作用,采用瞬态光谱技术和GC-MS技术分别对反应过程中产生的中间瞬态产物以及反应的最终产物进行了分析,对反应历程作了明确推断.研究表明,NO₃自由基首先从联苯的苯环上夺取电子形成电荷转移复合物,二级反应速率常数为8.24×10⁹L·mol^-1·s^-1;进而通过消除反应在苯环上定位形成邻-硝基联苯和对-硝基联苯,电荷转移复合物衰减表观的一级反应速率常数为2.30×10⁵s^-1.     

周边含己氧基的三代光致变色液晶树枝状大分子的光化学

报道了新化合物含108个己氧基端基的三代(G3)碳硅烷光致变色液晶树状大分子在溶液中的反-顺光异构化反应速率常数k_p, 光回复异构化正/逆反应速率常数k_t和k_c, 热回复异构化反应速率常数k_H, 光回复异构化反应平衡常数k_t/k_c, 活化能E, 异构转化率A/A₀及组分比A'/A₀. G3的光致变色反应速率常数的数量级为10^－1 s^－1, 而侧链含偶氮基元的光致变色聚硅氧烷的光致变色反应速率常数的数量级为10^－8 s^－1, 因此G3的光响应速率比后者快10⁷倍.     

流动态甲醇气相光催化降解的机制研究

在253.7 nm紫外光作用下, 研究纳米TiO₂光催化氧化流动态甲醇的机制, 结果表明, 甲醇的光催化降解不受水汽的影响, 只受氧气含量的影响. 在不含氧气的情况下, 即使有足量的水汽, 甲醇都不会有明显的降解. TiO₂受光诱导生成空穴-电子对后, 空穴直接氧化甲醇, 生成的甲醇正离子在氧气作用下进一步被氧化, 形成各种氧化产物. 甲醇氧化过程是多通道反应, 宏观表现为准一级反应. 空气和氧气条件下甲醇的总降解速率常数分别为9.78×10^－3和1.79×10^－2 s^－1.     

三代碳硅烷光致变色液晶树状物的光化学研究——端基含108个4-丁氧基偶氮苯介晶基元

报道了新化合物含108个丁氧基偶氮基元端基的三代(D3)碳硅烷光致变色液晶树状物在各溶液中的反-顺光异构化(光致变色)反应速率常数k_p, 光化学回复异构化正/逆反应速率常数k_t和k_c, 热回复异构化反应速率常数k_H, 光化学回复异构化反应平衡常数k_t/k_c, 活化能E, 异构化转换率及热回复异构化反应中的反-顺异构体组分比. D3的光致变色反应速率常数为10^－1 s^－1, 而含偶氮基元的光致变色液晶聚硅氧烷的光致变色反应速率常数为10^－8 s^－1, 因此, D3的光响应速度比后者快10⁷倍.     

基于偶氮桥连的新型双铁羰基配合物:Fe2(N2C5H10)(CO)6-x (PR3)x的合成及衍生

具有五元环结构的偶氮化合物4,4-二甲基-4,5-二氢-3H-吡咯（N₂C₅H₁₀）,与Fe₃（CO）₁₂在甲苯中加热回流反应,生成双铁六羰基配合物Fe₂（N₂C₅H₁₀）（CO）₆（1）.反应中N=N双键被还原,配体以（N₂C₅H₁₀）^2-的形式与Fe^IFe^I配位,形成具有蝶形结构的34e^-化合物.研究了在脱羰基试剂Me₃NO存在条件下,1和单齿膦配体PR₃反应生成Fe₂（N₂C₅H₁₀）-（CO）₅（PR₃）（PR₃=PPh₃,2a;PCy₃,2b）单取代配合物.光照条件下,化合物1中的CO配体还可以被双齿膦配体dppe[dppe=1,2-C₂H₄（PPh₂）₂]和dppbz[dppbz=1,2-C₆H₄（PPh₂）₂]取代,生成产物的类型和膦配体的夹角相关.与夹角较大的dppe反应,生成桥连产物Fe₂（N₂C₅H₁₀）（CO）₄（μ-dppe）（3a）;而与刚性较大的dppbz反应时,Fe₂（NR）₂的蝶形结构打开呈四元环;其中一个Fe上的CO被取代,dppbz与该Fe中心螯合,生成具有桥连CO的化合物Fe₂（N₂C₅H₁₀）（μ-CO）（CO）₄（κ²-dppbz）（3b）.合成具有Fe^I-CO-Fe^I结构的羰基化合物,一直是模拟[FeFe]氢化酶活性中心还原态结构Fe₂（SR）₂（μ-CO）-（CO）_5-xL_x的重要挑战.该类Fe₂（NR）₂（CO）_6-x（PR₃）_x化合物的合成,能为探索模拟[FeFe]氢化酶活性中心结构提供新的途径和思路.以上化合物均通过核磁[³¹P（¹H）NMR]、红外光谱（IR）、元素分析及X射线单晶结构衍射等表征.     

三种不同碳桥联双核茂钛配合物的合成及催化乙烯聚合研究

合成了3种不同结构的CnH₂n桥联双核茂钛配合物(CH₃)₂C[(C₅H₄)TiCl₂(C₅H₅)]₂(3),(CH₂)_n[(C₅H₄)TiCl₂(C₅H₅)]₂(6,n=3;7,n=4),并用1HNMR进行了表征.发现以甲苯为溶剂时,不仅提高了产率,而且有效地避免了副产物Cp₂TiCl₂的生成.研究了化合物7/MAO(甲基铝氧烷)催化乙烯聚合的反应,考察了反应条件对催化体系的影响.结果表明,催化活性随着n(Al)/n(Cat.)比的增大而提高,聚乙烯的分子量在n(Al)/n(Cat.)=500和50℃时达到最高值9.0102×10⁴;随着聚合时间的延长,催化活性下降,而产物分子量不断升高;随着温度的上升,50℃时催化活性和聚乙烯的分子量最高,分别为2.4074×10⁵gPE/(molTi·h)和6.8679×10⁴.随着桥联双核茂钛配合物碳桥的增长,催化活性增加,所得聚乙烯的分子量降低.     

266 nm光照下水溶液中氯苯与H2O2的反应机理研究

利用瞬态吸收光谱技术研究了不同条件下C₆H₅Cl与H₂O₂水溶液的激光闪光光解情况, 初步考察了其瞬态物种的生长和衰减等行为. 研究表明, •OH自由基和C₆H₅Cl反应生成C₆H₅Cl-OH adduct, 其反应速率常数在近中性、酸性条件下约为(5.89±0.65)×10⁹和(7.07±0.61)×10⁹ L•mol^－1•s^－1; 其衰减则符合双分子二级反应, 速率常数2k/εl＝1.1×10⁶ s^－1, 而在碱性时则为(4.34±0.51)×10⁹ L•mol^－1•s^－1, 衰减呈准一级反应, 速率常数为2.11×10⁵ s^－1. 在有氧条件下, O₂与C₆H₅Cl-OH adduct反应生成C₆H₅Cl-OHO₂ adduct, 其反应速率常数为6.8×10⁸ L•mol^－1•s^－1.     

Structure–reactivity relationships for the self‐ reactions of linear secondary alkylperoxy radicals: An experimental investigation

The self‐reactions of the linear pentylperoxy (C₅H₁₁O₂) and decylperoxy (C₁₀H₂₁O₂) radicals have been studied at room temperature. The technique of excimer laser flash photolysis was used to generate pentylperoxy radicals, while conventional flash photolysis was used for decylperoxy radicals. For the former, the recombination rate coefficients were estimated for the primary 1‐pentylperoxy isomer (n‐C₅H₁₁O₂) and for the secondary 2‐ and 3‐pentylperoxy isomers combined (“sec‐C₅H₁₁O₂”) by creating primary and secondary radicals in different ratios of initial concentrations and simulating experimental decay traces using a simplified chemical mechanism. The values obtained at 298 K were: k(n‐C₅H₁₁O₂+n‐C₅H₁₁O₂→Products)=(3.9±0.9)×10⁻¹³ cm³ molecule⁻¹ s⁻¹; k(sec‐C₅H₁₁O₂+sec‐C₅H₁₁O₂→Products)=(3.3±1.2)×10⁻¹⁴ cm³ molecule⁻¹ s⁻¹. Quoted errors are 1σ, whereas the total relative combined uncertainties correspond to an estimated uncertainty factor around 1.65. For decylperoxy radicals, the kinetics of all the types of secondary peroxy isomers reacting with each other were considered equivalent and grouped as sec‐C₁₀H₂₁O₂ (as for sec‐C₅H₁₁O₂). The UV absorption spectrum of these secondary radicals was measured, and the combined self‐reaction rate coefficients then derived as: k(sec‐C₁₀H₂₁O₂+sec‐C₁₀H₂₁O₂)=(9.4±1.3)×10⁻¹⁴ cm³ molecule⁻¹ s⁻¹ at 298 K. Again, quoted errors are 1σ and the total uncertainty factor corresponds to a value around 1.75. The sec‐dodecylperoxy radical was also investigated using the same procedure, but only an estimate of the rate coefficient could be obtained, due to aerosol formation in the reaction cell: k(sec‐C₁₂H₂₅O₂+sec‐C₁₂H₂₅O₂)≡1.4×10⁻¹³ cm³ molecule⁻¹ s⁻¹, with an uncertainty factor of about 2. Despite the fairly high uncertainty factors, a relationship has been identified between the room‐temperature rate coefficient for the self‐reaction and the number of carbon atoms, n, in the linear secondary radical, suggesting: log(k(sec‐RO₂+sec‐RO₂)/cm³ molecule⁻¹ s⁻¹)=−13.0–3.2×exp(−0.64×(n‐2.3)). Concerning primary linear alkylperoxy radicals, no real trend in the self‐reaction rate coefficient can be identified, and an average value of 3.5×10⁻¹³ cm³ molecule⁻¹ s⁻¹ is proposed for all radicals. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet: 31: 37–46, 1999     

[Me3NC2H4OH]Zn2Cl5水溶液的激光光解研究

利用时间分辨激光光解技术研究了季铵盐型离子液体[Me₃NC₂H₄OH]Zn₂Cl₅(简写R-Zn₂Cl₅)的光解行为, 研究发现离子液体能被266 nm激光单光子电离, 生成阳离子自由基、[Zn₂Cl₅]^•中性自由基和水合电子, 观察到胆碱激发三线态的存在, 并测定了离子液体光电离的量子产额为0.04. 利用266 nm激光对离子液体、胆碱、氯化锌、氯化钠的光解行为比较, 发现胆碱阳离子的贡献很小, [Zn₂Cl₅]^－阴离子起主要作用. 采用氧化性自由基SO₄^•－引发离子自由基, 揭示其光电离机理, 测定离子液体的动力学反应速率常数, SO₄^•－ 460 nm的衰减速率常数为1.3×10⁹ L•mol^－1•s^－1, 320 nm离子自由基瞬态产物的生成速率常数为1.5×10⁹ L•mol^－1•s^－1, 两者很接近, 说明SO₄^•－自由基的衰减与瞬态自由基的生成是同步的.     

The rate of the reactions of C2O radicals with H and H2

The rate constants for the reactions C₂O + H → products (1) and C₂O + H₂ → products (2) have been determined at room temperature by means of laser-induced fluorescence detection of C₂O radicals, generated either by the KrF excimer laser photolysis Of C₃O₂, or by the reaction of C₃O₂ with O atoms. Values of k₁ = (3.7 ± 1.0) × 10^?11 cm³ s^?1 and k₂ = (7 ± 3) × 10^?13 cm³ s^?1 were obtained.     

Temperature-dependent kinetics studies of the reactions of C2H5O2 and n-C3H7O2 radicals with NO

The rate coefficients for the gas-phase reactions of C₂H₅O₂ and n-C₃H₇O₂ radicals with NO have been measured over the temperature range of (201–403) K using chemical ionization mass spectrometric detection of the peroxy radical. The alkyl peroxy radicals were generated by reacting alkyl radicals with O₂, where the alkyl radicals were produced through the pyrolysis of a larger alkyl nitrite. In some cases C₂H₅ radicals were generated through the dissociation of iodoethane in a low-power radio frequency discharge. The discharge source was also tested for the i-C₃H₇O₂ + NO reaction, yielding k_{298 K} = (9.1 ± 1.5) × 10⁻¹² cm³ molecule⁻¹ s⁻¹, in excellent agreement with our previous determination. The temperature dependent rate coefficients were found to be k(T) = (2.6 ± 0.4) × 10⁻¹² exp{(380 ± 70)/T} cm³ molecule⁻¹ s⁻¹ and k(T) = (2.9 ± 0.5) × 10⁻¹² exp{(350 ± 60)/T} cm³ molecule⁻¹ s⁻¹ for the reactions of C₂H₅O₂ and n-C₃H₇O₂ radicals with NO, respectively. The rate coefficients at 298 K derived from these Arrhenius expressions are k = (9.3 ± 1.6) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ for C₂H₅O₂ radicals and k = (9.4 ± 1.6) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ for n-C₃H₇O₂ radicals. © 1996 John Wiley & Sons, Inc.     

Kinetic study of the reaction of OH with HCl from 240–1055 K

Absolute rate coefficients for the reaction of OH with HCl (k₁) have been measured as a function of temperature over the range 240–1055 K. OH was produced by flash photolysis of H₂O at λ > 165 nm, 266 nm laser photolysis of O₃/H₂O mixtures, or 266 nm laser photolysis of H₂O₂. OH was monitored by time-resolved resonance fluorescenceor pulsed laser–induced fluorescence. In many experiments the HCl concentration was measured in situ in the slow flow reactor by UV photometry. Over the temperature range 240–363 K the following Arrhenius expression is an adequate representation of the data: k₁ = (2.4 ± 0.2) × 10^?12 exp[?(327 ± 28)/T]cm³ molecule^?1 s^?1. Over the wider temperature range 240–1055 K, the temperature dependence of k₁ deviates from the Arrhenius form, but is adequately described by the expression k₁ = 4.5 × 10^?17 T^1.65 exp(112/T) cm³ molecule^?1 s^?1. The error in a calculated rate coefficient at any temperature is 20%.     

Rate constant and a detailed error analysis for C2H3 + H reaction

The production and reactions of vinyl radicals and hydrogen atoms from the photolysis of vinyl iodide (C₂H₃I) at 193 nm have been examined employing laser photolysis coupled to kinetic-absorption spectroscopic and gas chromatographic product analysis techniques. The time history of vinyl radicals in the presence of hydrogen atoms was monitored using the 1,3-butadiene (the vinyl radical combination product) absorption at 210 nm. By employing kinetic modeling procedures a rate constant of 1.8 × 10^?10 cm² molecule^?1 s^?1 for the reaction C₂H₃ + H has been determined at 298 K and 27 KPa (200 torr) pressure. A detailed error analysis for determination of the C₂H₃ + H reaction rate constant, the initial C₂H₃ and H concentrations are performed. A combined uncertainty of ±0.43 × 10^?10 cm² molecule^?1 s^?1 for the above measured rate constant has been evaluated by combining the contribution of the random errors and the systematic errors (biases) due to uncertainties of each known parameter used in the modeling. © 1995 John Wiley & Sons, Inc.     

Rate constants for the reactions of C2H5O,i‐C3H7O,and n‐C3H7O with NO and O2 as a function of temperature

The rate constants of the reactions of ethoxy (C₂H₅O), i‐propoxy (i‐C₃H₇O) and n‐propoxy (n‐C₃H₇O) radicals with O₂ and NO have been measured as a function of temperature. Radicals have been generated by laser photolysis from the appropriate alkyl nitrite and have been detected by laser‐induced fluorescence. The following Arrhenius expressions have been determined: (R₁) C₂H₅O + O₂ → products k₁ = (2.4 ± 0.9) × 10⁻¹⁴ exp(−2.7 ± 1.0 kJmol⁻¹/RT) cm³ s⁻¹ 295K < T < 354K p = 100 Torr (R₂) i‐C₃H₇O + O₂ → products k₂ = (1.6 ± 0.2) × 10⁻¹⁴ exp(−2.2 ± 0.2 kJmol⁻¹/RT) cm³ s⁻¹ 288K < T < 364K p = 50–200 Torr (R₃) n‐C₃H₇O + O₂ → products k₃ = (2.5 ± 0.5) × 10⁻¹⁴ exp(−2.0 ± 0.5 kJmol⁻¹/RT) cm³ s⁻¹ 289K < T < 381K p = 30–100 Torr (R₄) C₂H₅O + NO → products k₄ = (2.0 ± 0.7) × 10⁻¹¹ exp(0.6 ± 0.4 kJmol⁻¹/RT) cm³ s⁻¹ 286K < T < 388K p = 30–500 Torr (R₅) i‐C₃H₇O + NO → products k₅ = (8.9 ± 0.2) × 10⁻¹² exp(3.3 ± 0.5 kJmol⁻¹/RT) cm³ s⁻¹ 286K < T < 389K p = 30–500 Torr (R₆) n‐C₃H₇O + NO → products k₆ = (1.2 ± 0.2) × 10⁻¹¹ exp(2.9 ± 0.4 kJmol⁻¹/RT) cm³s⁻¹ 289K < T < 380K p = 30–100 Torr All reactions have been found independent of total pressure between 30 and 500 Torr within the experimental error. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 860–866, 1999     

Rate constants for the elementary reactions between CN radicals and CH4, C2H6, C2H4, C3H6, and C2H2 in the range: 295 ⩽ T/K ⩽ 700

Pulsed laser photolysis, time-resolved laser-induced fluorescence experiments have been carried out on the reactions of CN radicals with CH₄, C₂H₆, C₂H₄, C₃H₆, and C₂H₂. They have yielded rate constants for these five reactions at temperatures between 295 and 700 K. The data for the reactions with methane and ethane have been combined with other recent results and fitted to modified Arrhenius expressions, k(T) = A′(298) (T/298)ⁿ exp(?θ/T), yielding: for CH₄, A′(298) = 7.0 × 10^?13 cm³ molecule^?1 s^?1, n = 2.3, and θ = ?16 K; and for C₂H₆, A′(298) = 5.6 × 10^?12 cm³ molecule^?1 s^?1, n = 1.8, and θ = ?500 K. The rate constants for the reactions with C₂H₄, C₃H₆, and C₂H₂ all decrease monotonically with temperature and have been fitted to expressions of the form, k(T) = k(298) (T/298)ⁿ with k(298) = 2.5 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.24 for CN + C₂H₄; k(298) = 3.4 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.19 for CN + C₃H₆; and k(298) = 2.9 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.53 for CN + C₂H₂. These reactions almost certainly proceed via addition-elimination yielding an unsaturated cyanide and an H-atom. Our kinetic results for reactions of CN are compared with those for reactions of the same hydrocarbons with other simple free radical species. © John Wiley & Sons, Inc.     

Temperature Dependence Kinetic Studies of the Reaction of O(3P) with CHI3 and C2H5I and the 298 K Reaction of OH(X2Π) with CHI3

A flash photolysis–resonance fluorescence technique was used to investigate the kinetics of the OH(X²Π) radical and O(³P) atom‐initiated reactions with CHI₃ and the kinetics of the O(³P) atom‐initiated reaction with C₂H₅I. The reactions of the O(³P) atom with CHI₃ and C₂H₅I were studied over the temperature range of 296 to 373 K in 14 Torr of helium, and the reaction of the OH (X²Π) radical with CHI₃ was studied at T = 298 K in 186 Torr of helium. The experiments involved time‐resolved resonance fluorescence detection of OH (A²Σ⁺ → X²Π transition at λ = 308 nm) and of O(³P) (λ = 130.2, 130.5, and 130.6 nm) following flash photolysis of the H₂O/He, H₂O/CHI₃/He, O₃/He, and O₃/C₂H₅I/He mixtures. A xenon vacuum UV (VUV) flash lamp (λ > 120 nm) served as a photolysis light source. The OH radicals were produced by the VUV flash photolysis of water, and the O(³P) atoms were produced by the VUV flash photolysis of ozone. Decays of OH radicals and O(³P) atoms in the presence of CHI₃ and C₂H₅I were observed to be exponential, and the decay rates were found to be linearly dependent on the CHI₃ and C₂H₅I concentrations. Measured rate coefficients for the reaction of O(³P) atoms with CHI₃ and C₂H₅I are described by the following Arrhenius expressions (units are cm³ s^?1): k_O+C2H5I(T) = (17.2 ± 7.4) × 10^?12 exp[?(190 ± 140)K/T] and k_O+CHI3(T) = (1.80 ± 2.70) × 10^?12 exp[?(440 ± 500)K/T]; the 298 K rate coefficient for the reaction of the OH radical with CHI₃ is k_OH+CHI3(298 K) = (1.65 ± 0.06) × 10^?11 cm³ s^?1. The listed uncertainty values of the Arrhenius parameters are 2σ‐standard errors of the calculated slopes by linear regression.