乙醛水合物自由基 | 75389-20-7

• 分子结构分类: 有机化合物 - 有机氧化合物
• 中文名称: 乙醛水合物自由基
• 英文名称: acetaldehyde hydrate radical
• 英文别名: 1,1-dihydroxy-ethyl；dihydroxyethyl radical
• CAS: 75389-20-7
• 化学式: C₂H₅O₂
• 分子量: 61.0605
• InChiKey: LFZQTYUEPZXJBU-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.24
• 重原子数：
  4.0
• 可旋转键数：
  0.0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  40.46
• 氢给体数：
  2.0
• 氢受体数：
  2.0

反应信息

• 作为反应物：
  描述：

  乙醛水合物自由基 在 四硝基甲烷 、 一氧化二氮 作用下， 生成 乙酸盐 、 alkaline earth salt of/the/ methylsulfuric acid
  参考文献：
  名称：

  乙酰基的快速水合。乙醛在水溶液中的脉冲辐解研究。

  摘要：

  在水溶液中，乙醛及其水合物处于 0.8:1 的平衡状态。N/sub 2/O 饱和水的脉冲辐射分解产生的羟基自由基与该混合物反应，总速率常数 k = 2.4 x 10/sup 9/dm/sup 3/mol/sup -1/s/sup -1/，与乙醛的反应速度比与水合物的反应速度快约 3 倍。形成的主要自由基是乙酰基及其水合形式，甲基上的 H-抽象仅发生约 5-10%。乙酰基快速水合，其水合速率比母体化合物乙醛快 2 x 10/sup 6/ 倍。水合乙酰基自由基通过四硝基甲烷的快速还原、/sub 2//sup .-/ 在氧气存在下的形成以及在 pH 11 (pK/sub a/ /<=/ 9.5) 下的去质子化来监测。乙酰基在脉冲辐解时间尺度上不会氧化 N,N,N',N'-四甲基-对苯二胺 (TMPD)，但乙酰过氧自由基（在氧气存在下形成）与 TMPD、抗坏血酸、和 O/sub 2//sup .-

  DOI：

  10.1021/ja00225a019
• 作为产物：
  描述：

  acetyl radical 在 一氧化二氮 作用下， 生成 乙醛水合物自由基
  参考文献：
  名称：

  乙酰基的快速水合。乙醛在水溶液中的脉冲辐解研究。

  摘要：

  在水溶液中，乙醛及其水合物处于 0.8:1 的平衡状态。N/sub 2/O 饱和水的脉冲辐射分解产生的羟基自由基与该混合物反应，总速率常数 k = 2.4 x 10/sup 9/dm/sup 3/mol/sup -1/s/sup -1/，与乙醛的反应速度比与水合物的反应速度快约 3 倍。形成的主要自由基是乙酰基及其水合形式，甲基上的 H-抽象仅发生约 5-10%。乙酰基快速水合，其水合速率比母体化合物乙醛快 2 x 10/sup 6/ 倍。水合乙酰基自由基通过四硝基甲烷的快速还原、/sub 2//sup .-/ 在氧气存在下的形成以及在 pH 11 (pK/sub a/ /<=/ 9.5) 下的去质子化来监测。乙酰基在脉冲辐解时间尺度上不会氧化 N,N,N',N'-四甲基-对苯二胺 (TMPD)，但乙酰过氧自由基（在氧气存在下形成）与 TMPD、抗坏血酸、和 O/sub 2//sup .-

  DOI：

  10.1021/ja00225a019

文献信息

• A novel long path photolysis cell—application to the reactivity of selected organic compounds toward the nitrate radical (NO₃)
  作者：Davy Rousse、Christian George

  DOI：10.1039/b400175c

  日期：——

  Bimolecular rate coefficients for the reactions of the nitrate radical, NO3, with methanol, ethanol, acetaldehyde tert-butyl methyl ether, propionic acid, dimethylmalonate, dimethylsuccinate, dimethyl carbonate and diethylcarbonate in aqueous solutions have been measured using a novel experimental approach. This study was performed using laser flash photolysis (LFP) with a capillary made of Teflon AF2400 as a long path capillary photolysis cell. Taking benefit of this new material allowing a long optical path length for a very limited irradiated solution volume, new rate constants were established. All experiments were carried out at room temperature. Measured rate coefficients for the reaction of the NO3 radical with methanol, ethanol, acetaldehyde, dimethylcarbonate, diethylcarbonate, dimethylmalonate, dimethyl succinate, propionic acid and tert-butyl-methyl ether are (units are 105 M−1 s−1): kNO3 + ethanol = 4.8 ± 0.5, kNO3 + ethanol = 19 ± 3, kNO3 + acetaldehyde = 20 ± 3, kNO3 + dimethylcarbonate = 0.15 ± 0.04, kNO3 + diethylcarbonate = 0.84 ± 0.12, kNO3 + dimethylmalonate = 0.26 ± 0.07, kNO3 + dimethylsuccinate = 0.34 ± 0.02, kNO3 + propionic acid = 0.77 ± 0.02, kNO3 + tert-butyl-methyl ether = 3.9 ± 1.3. The uncertainties in the above expressions are ±2σ and represent precision only. The reported rate coefficients for the reactions of NO3 with methanol, ethanol and acetaldehyde agree well with currently recommended values. To date, there is no kinetic data reported in the literature for the NO3 radical reaction with dimethylcarbonate, diethylcarbonate, dimethylmalonate, dimethylsuccinate, propionic acid and tert-butyl-methyl ether. The reaction mechanism is briefly discussed as a function of bond energies

  已使用一种新颖的实验方法测量了硝酸根自由基（NO3）与甲醇、乙醇、乙醛、叔丁基甲基醚、丙酸、二甲基马来酸盐、二甲基丁二酸盐、碳酸二甲酯和碳酸二乙酯在水溶液中的双分子反应速率系数。该研究采用激光闪光光解法（LFP），使用由特氟龙AF2400制成的毛细管作为长光程光解池。得益于这种新材料，它允许在非常有限的辐照溶液体积内实现较长的光学路径长度，建立了新的速率常数。所有实验均在室温下进行。 自由基与甲醇、乙醇、乙醛、二甲基碳酸酯、二乙基碳酸酯、二甲基马来酸盐、二甲基丁二酸盐、丙酸和叔丁基甲基醚反应的速率系数（单位为 10⁵ M⁻¹ s⁻¹）为：k + 乙醇 = 4.8 ± 0.5, k + 乙醇 = 19 ± 3, k + 乙醛 = 20 ± 3, k + 二甲基碳酸酯 = 0.15 ± 0.04, k + 二乙基碳酸酯 = 0.84 ± 0.12, k + 二甲基马来酸盐 = 0.26 ± 0.07, k + 二甲基丁二酸盐 = 0.34 ± 0.02, k + 丙酸 = 0.77 ± 0.02, k + 叔丁基甲基醚 = 3.9 ± 1.3。上述表达式中的不确定性为 ±2σ，仅表示精确度。 与甲醇、乙醇和乙醛反应的速率系数与目前推荐的值高度一致。到目前为止，文献中尚无 自由基与二甲基碳酸酯、二乙基碳酸酯、二甲基马来酸盐、二甲基丁二酸盐、丙酸和叔丁基甲基醚反应的动力学数据。反应机制将简要讨论作为键能的函数。
• Infrared Frequency-Modulation Probing of Product Formation in Alkyl + O₂ Reactions:  I. The Reaction of C₂H₅ with O₂ between 295 and 698 K
  作者：Eileen P. Clifford、John T. Farrell、John D. DeSain、Craig A. Taatjes

  DOI：10.1021/jp0024874

  日期：2000.12.1

  The production of HO2 in the reaction of ethyl radicals with molecular oxygen has been investigated using laser photolysis/cw infrared frequency modulation spectroscopy. The ethyl radicals are formed by reaction of photolytically produced Cl atoms with ethane, initiated via pulsed laser photolysis of Cl-2 and the progress of the reaction is monitored by frequency-modulation spectroscopy of the HO2 product. The yield of HO2 in the reaction is measured by comparison with the Cl-2/CH3OH/O-2 system, which quantitatively converts Cl atoms to HO2. At low temperatures stabilization to C2H5O2 dominates, but at elevated temperatures (> 575 K) dissociation of the ethylperoxy radical begins to contribute. Biexponential time behavior of the HO2 production allows separation of prompt, "direct" HO2 formation from HO2 produced after thermal redissociation of an Initial ethylperoxy adduct, The prompt HO2 yield exhibits a smooth increase with increasing temperature, but the total HO2 yield, which includes contributions from the redissociation of ethylperoxy radicals, rises sharply from similar to 10% to 100% between 575 and 675 K. Because of the separation of time scales in the HO2 production, this rapid rise can unambiguously be assigned to ethylperoxy dissociation. No OH was observed in the reaction, and an upper limit of 6% can be placed on direct OH formation from the C2H5 + O-2 reaction at 700 K. The time behavior of the HO2 production is at variance with the predictions of Wagner et al.'s RRKM-based parameterization of this reaction (J. Phys. Chem. 1990, 94, 1853). However, a simple ad hoc correction to that model, which takes into account a recent reinterpretation of the equilibrium constant for C2H5 + O-2 Ct C2H5O2, predicts yields and time constants consistent with the present measurements. The reaction mechanism is further discussed in terms of recent quantum chemical and master equation studies of this system, which show that the present results are well described by a coupled mechanism with HO2 + C2H4 formed by direct elimination from the C2H5O2 adduct.