异丁基自由基 | 4630-45-9

• 分子结构分类: 有机化合物 - 碳氢化合物 - 饱和烃
• 中文名称: 异丁基自由基
• 英文名称: isobutyl radical
• 英文别名: Isobutyl-Radikal；isobutyl；i-Butylradikal
• CAS: 4630-45-9
• 化学式: C₄H₉
• 分子量: 57.1155
• InChiKey: KTOQRRDVVIDEAA-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  4
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.75
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为反应物：
  描述：

  异丁基自由基 生成 2,5-二甲基己烷
  参考文献：
  名称：

  The Disproportionation and Combination Reactions of Butyl Free Radicals¹

  摘要：

  DOI：

  10.1021/ja01579a024
• 作为产物：
  描述：

  二异丁基酮 生成 异丁基自由基
  参考文献：
  名称：

  The Disproportionation and Combination Reactions of Butyl Free Radicals¹

  摘要：

  DOI：

  10.1021/ja01579a024

文献信息

• Study of the methyl–isobutane reaction in the range 478 ⩽T/K ⩽ 560
  作者：Christopher Anastasi

  DOI：10.1039/f19837900741

  日期：——

  modulation spectrometer (m.m.s.) has been modified to extend its operating temperature into a regime where methyl reactions of current interest may be conveniently studied. In this paper we present the first direct measurements on the reaction of methyl radicals with isobutane in the range 478 ⩽T/K ⩽ 560.

  现有分子调制光谱仪（mms）中的反应器设计已进行了修改，以将其工作温度扩展到可以方便地研究当前感兴趣的甲基反应的范围。在本文中，我们提出在范围478⩽上甲基基团的用异丁烷反应的第一直接测量Ť / K⩽560。
• Homolytic dissociation of 1-substituted cyclohexa-2,5-diene-1-carboxylic acids: an EPR spectroscopic study of chain propagation†
  作者：Leon V. Jackson、John C. Walton

  DOI：10.1039/b104859g

  日期：——

  Hydrogen abstraction from 1-substituted cyclohexa-2,5-diene-1-carboxylic acids containing linear, branched and cyclic alkyl substituents, as well as allyl, propargyl (prop-2-ynyl), cyanomethyl and benzyl substituents, has been studied by EPR spectroscopy. For each carboxylic acid, EPR spectra of the corresponding cyclohexadienyl radicals were observed at lower temperatures, followed by spectra due to ejected carbon-centred radicals at higher temperatures. Rate constants, for release of the carbon-centred radicals from the cyclohexadienyl radicals, were determined from radical concentration measurements for the above range of substituents. The rate of cyclohexadienyl radical dissociation increased with branching in the 1-alkyl substituent and with electron delocalisation in the ejected carbon-centred radical; 3,5- and 2,6-dimethyl-substitution of the cyclohexadienyl ring led to reductions in the dissociation rate constants. Rate data for abstraction of bisallylic hydrogens from the cyclohexadienyl acids were also obtained for ethyl, n-propyl and isopropyl radicals. These results indicated a sharp drop in the rate of hydrogen abstraction as the degree of branching in the attacking radical increased. Small decreases in the hydrogen abstraction rate constants were observed for cyclohexadienes containing CO2R substituents.

  通过电子顺磁共振（EPR）光谱研究了从含有线性、支化、环状烷基取代基以及烯丙基、炔丙基（丙-2-炔基）、氰基甲基和苄基取代基的1-取代环己-2,5-二烯-1-羧酸中提取氢的反应。对于每种羧酸，在较低温度下观察到相应的环己二烯基自由基的EPR谱，随后在较高温度下观察到由喷出的碳中心自由基引起的谱。通过对于上述范围的取代基的自由基浓度测量，确定了从环己二烯基自由基释放碳中心自由基的速率常数。环己二烯基自由基解离速率随着1-烷基取代基的分支增加和喷出的碳中心自由基的电子离域程度增加而加快；环己二烯环的3,5-和2,6-二甲基取代导致解离速率常数降低。还获得了从环己二烯羧酸中提取双烯丙基氢的速率数据，涉及乙基、正丙基和异丙基自由基。这些结果表明，随着攻击自由基的分支程度增加，氢提取速率急剧下降。环己二烯中含有CO2R取代基时，氢提取速率常数略有下降。
• The reactivity of ketyl and alkyl radicals in reactions with carbonyl compounds
  作者：E. T. Denisov

  DOI：10.1007/bf02494263

  日期：1998.11

  parabolic model of bimolecular radical reactions was used for analysis of the hydrogen transfer reactions of ketyl radicals: >C·OH+R1COR2→>C=O+R1R2C·OH. The parameters describing the reactivity of the reagents were calculated from the experimental data. The parameters that characterize the reactions of ketyl and alkyl radicals as hydrogen donors with olefins and with carbonyl compounds were obtained: >C·OH

  双分子自由基反应的抛物线模型用于分析羰基自由基的氢转移反应：>C·OH+R1COR2→>C=O+R1R2C·OH。描述试剂反应性的参数由实验数据计算。得到表征作为氢供体的羰基和烷基自由基与烯烃和羰基化合物反应的参数：>C·OH+R1CH=CH2→>C=O+R1C·HCH3；>R1CH=CH2+R2C·HCH2R3→R2C·HCH3+R2CH=CHR3。这些参数用于计算这些转换的活化能。比较了自由基和分子（醛、酮和醌）从 C-H 和 O-H 键夺氢反应的动力学参数。
• Kinetics of the reactions of () and () atoms with C3H8,C3D8, n-C4H10, and i-C4H10 at 298 K
  作者：Kanami Hitsuda、Kenshi Takahashi、Yutaka Matsumi、Timothy J. Wallington

  DOI：10.1016/s0009-2614(01)00947-2

  日期：2001.9

  The title reactions were studied using laser flash photolysis in conjunction with vacuum ultraviolet laser-induced fluorescence techniques. Separate monitoring of the two spin orbit states, and , was used to measure the kinetics of the chemical reactions of and , and physical quenching of . The rate constants for chemical reactions of atoms with C3H8, n-C4H10, and i-C4H10 are approximately 30% of those

  使用激光闪光光解结合真空紫外激光诱导的荧光技术研究了标题反应。单独的监控两个自旋轨道状态，并且，被用于测量的化学反应的动力学和，和物理淬火。原子与C 3 H 8，n -C 4 H 10和i -C 4 H 10进行化学反应的速率常数约为原子的30％。没有观察到原子与C 3 D 8发生化学反应和C 2 H 6（＜17％的反应速率）。
• Kinetics and thermochemistry of the R+HBr⇄RH+Br (R=n-C3H7, isoC3H7, n-C4H9, isoC4H9, sec-C4H9 or tert-C4H9) equilibrium
  作者：Jorma A. Seetula、Irene R. Slagle

  DOI：10.1039/a608224f

  日期：——

  The kinetics of the reactions of n-C 3 H 7 , isoC 3 H 7 , n-C 4 H 9 , isoC 4 H 9 , sec-C 4 H 9 and tert-C 4 H 9 radicals, R, with HBr have been investigated in a heatable tubular reactor coupled to a photoionization mass spectrometer. The reactions were studied by a time-resolved technique under pseudo-first-order conditions, where the rate constants of R+HBr reactions were obtained by monitoring the decay of the radical as a function of time. The radical was photogenerated in situ in the flow reactor by pulsed 248 nm exciplex laser radiation. All six reactions were studied separately over a wide range of temperatures and, in these temperature ranges, the rate constants determined were fitted to an Arrhenius expression (error limits stated are 1σ+Students t values, units cm 3 molecule -1 s -1 ): k(n-C 3 H 7 )=(1.6±0.2) ×10 -12 exp[+(5.4±0.2) kJ mol -1 /RT], k(isoC 3 H 7 )=(1.4±0.2)×10 -12 exp[+(6.9±0.2) kJ mol -1 /RT], k(n-C 4 H 9 )=(1.3±0.2) ×10 -12 exp[+(6.4±0.4) kJ mol -1 /RT], k(isoC 4 H 9 )=(1.4±0.2) ×10 -12 exp[+(6.1±0.2) kJ mol -1 /RT], k(sec-C 4 H 9 )=(1.4±0.3) ×10 -12 exp[+(7.5±0.3) kJ mol -1 /RT] and k(tert-C 4 H 9 )=(1.2±0.3 )×10 -12 exp[+(8.3±0.3) kJ mol -1 /RT]. The kinetic information was combined with the kinetics of the Br+RH reactions to calculate the entropy and the heat of formation values for the radicals studied. The thermodynamic values were obtained at 298 K using a second-law procedure. The entropy values and enthalpies of formation are (entropy in J K -1 mol -1 and enthalpy in kJ mol -1 ): 284±5, 100.8±2.1 (n-C 3 H 7 ); 281±5, 86.6±2.0 (isoC 3 H 7 ); 329±5, 80.9±2.2 (n-C 4 H 9 ); 316±5, 72.7±2.2 (isoC 4 H 9 ); 330±5, 66.7±2.1 (sec-C 4 H 9 ) and 315±4, 51.8±1.3 (tert-C 4 H 9 ). The C–H bond strength of analogous saturated hydrocarbons derived from the enthalpy of reaction values are (in kJ mol -1 ): 423.3±2.1 (primary C–H bond in propane), 409.1±2.0 (secondary C–H bond in propane), 425.4±2.1 (primary C–H bond in n-butane), 425.2±2.1 (primary C–H bond in isobutane), 411.2±2.0 (secondary C–H bond in n-butane) and 404.3±1.3 (tertiary C–H bond in isobutane). The enthalpy of formation values are used in group additivity calculations to estimate Δ f H 298 ° values of six pentyl and four hexyl free radical isomers.

  n-C₃H₇、isoC₃H₇、n-C₄H₉、isoC₄H₉、sec-C₄H₉和tert-C₄H₉自由基R与HBr的反应动力学已在一台可加热的管式反应器中进行研究，并与光电离质谱仪联结。反应通过伪一阶条件下的时间分辨技术进行研究，R+HBr反应的速率常数是通过监测自由基随时间的衰减获得的。自由基是在流动反应器中通过脉冲248 nm的激发态激光辐射原位光生。六种反应都在广泛的温度范围内分别研究，在这些温度范围内，测定的速率常数拟合到Arrhenius表达式（所声明的误差限是1σ+学生t值，单位为cm³ molecule⁻¹ s⁻¹）： k(n-C₃H₇) = (1.6±0.2) × 10⁻¹² exp[+(5.4±0.2) kJ mol⁻¹ /RT]， k(isoC₃H₇) = (1.4±0.2) × 10⁻¹² exp[+(6.9±0.2) kJ mol⁻¹ /RT]， k(n-C₄H₉) = (1.3±0.2) × 10⁻¹² exp[+(6.4±0.4) kJ mol⁻¹ /RT]， k(isoC₄H₉) = (1.4±0.2) × 10⁻¹² exp[+(6.1±0.2) kJ mol⁻¹ /RT]， k(sec-C₄H₉) = (1.4±0.3) × 10⁻¹² exp[+(7.5±0.3) kJ mol⁻¹ /RT]， k(tert-C₄H₉) = (1.2±0.3) × 10⁻¹² exp[+(8.3±0.3) kJ mol⁻¹ /RT]。 这些动力学信息与Br+RH反应的动力学结合，用于计算所研究自由基的熵和形成热值。这些热力学值是在298 K下通过第二法则程序获得的。熵值和形成焓为（熵单位为J K⁻¹ mol⁻¹，焓单位为kJ mol⁻¹）：284±5, 100.8±2.1 (n-C₃H₇)；281±5, 86.6±2.0 (isoC₃H₇)；329±5, 80.9±2.2 (n-C₄H₉)；316±5, 72.7±2.2 (isoC₄H₉)；330±5, 66.7±2.1 (sec-C₄H₉) 和 315±4, 51.8±1.3 (tert-C₄H₉)。 根据反应焓值推导的类似饱和烃的C-H键强度为（单位为kJ mol⁻¹）：423.3±2.1（丙烷的原级C-H键），409.1±2.0（丙烷的次级C-H键），425.4±2.1（正丁烷的原级C-H键），425.2±2.1（异丁烷的原级C-H键），411.2±2.0（正丁烷的次级C-H键）和404.3±1.3（异丁烷的三级C-H键）。形成焓值用于分组加法计算，以估计六个戊基和四个己基自由基异构体的ΔfH₂₉₈°值。