Mechanistical study on the formation of hydroxyacetone (CH 3 COCH 2 OH), methyl acetate (CH 3 COOCH 3 ), and 3-hydroxypropanal (HCOCH 2 CH 2 OH) along with their enol tautomers (prop-1-ene-1,2-diol (CH 3 C(OH)CHOH), prop-2-ene-1,2-diol (CH 2 C(OH)CH 2 OH)
Mechanistical study on the formation of hydroxyacetone (CH 3 COCH 2 OH), methyl acetate (CH 3 COOCH 3 ), and 3-hydroxypropanal (HCOCH 2 CH 2 OH) along with their enol tautomers (prop-1-ene-1,2-diol (CH 3 C(OH)CHOH), prop-2-ene-1,2-diol (CH 2 C(OH)CH 2 OH)
复制标题
羟基丙酮 (CH 3 COCH 2 OH)、乙酸甲酯 (CH 3 COOCH 3 ) 和 3-羟基丙醛 (HCOCH 2 CH 2 OH) 及其烯醇互变异构体 (prop-1-ene-1,2) 的形成机理研究
DOI：
10.1039/d2cp03543j
复制
发表时间：
2023
影响因子：
3.3
通讯作者：
Kaiser, Ralf I.
中科院分区：
文献类型：
--
作者：
Wang, Jia;Marks, Joshua H.;Turner, Andrew M.;Nikolayev, Anatoliy A.;Azyazov, Valeriy;Mebel, Alexander M.;Kaiser, Ralf I.
我们首次揭示了羟基丙酮（CH3COCH2OH）、乙酸甲酯（CH3COOCH3）和3-羟基丙烷（HCOCH2CH2OH）及其烯醇互变异构体在甲醇（CH3OH）和乙醛（CH3CHO）混合冰中的形成途径，类似于ISM中暴露在5 K超低温电离辐射下的星际冰。利用光解离反射飞行时间质谱（PI-ReToF-MS）和同位素标记的冰，反应产物被选择性地光解离，从而在程序升温的脱附阶段对异构体进行区分。基于不同质荷比和确定物种的电离能,我们揭示丙酮醇的形成途径(CH3COCH2OH),乙酸甲酯(CH3COOCH3)和3-hydroxypropanal (HCOCH2CH2OH)通过radical-radical复合反应和烯醇互变异构体的(prop-1-ene-1,可(CH3C (OH) CHOH), prop-2-ene-1,可(CH2C (OH) CH2OH), 1-methoxyethen-1-ol (CH3OC (OH) CH2)和prop-1-ene-1 3-diol (HOCH2CHCHOH))通过keto-enol互变异构化。据我们所知，1-甲氧基-1-醇（CH3OC(OH)CH2）和1-烯-1,3-二醇（HOCH2CHCHOH）是首次通过实验鉴定出来的。我们的发现有助于限制在恒星形成区域内检测到的羟丙酮和乙酸甲酯的形成机制，并表明迄今为止在天文学上未被发现的异构体3-羟基丙烷及其烯醇互变异构体是未来天文学搜索的有希望的候选者。这些烯醇互变异构体由于其亲核特性和高反应活性，可能有助于深空生物相关分子的分子合成。
We unravel, for the very first time, the formation pathways of hydroxyacetone (CH3COCH2OH), methyl acetate (CH3COOCH3), and 3-hydroxypropanal (HCOCH2CH2OH), as well as their enol tautomers within mixed ices of methanol (CH3OH) and acetaldehyde (CH3CHO) analogous to interstellar ices in the ISM exposed to ionizing radiation at ultralow temperatures of 5 K. Exploiting photoionization reflectron time-of-flight mass spectrometry (PI-ReToF-MS) and isotopically labeled ices, the reaction products were selectively photoionized allowing for isomer discrimination during the temperature-programmed desorption phase. Based on the distinct mass-to-charge ratios and ionization energies of the identified species, we reveal the formation pathways of hydroxyacetone (CH3COCH2OH), methyl acetate (CH3COOCH3), and 3-hydroxypropanal (HCOCH2CH2OH) via radical–radical recombination reactions and of their enol tautomers (prop-1-ene-1,2-diol (CH3C(OH)CHOH), prop-2-ene-1,2-diol (CH2C(OH)CH2OH), 1-methoxyethen-1-ol (CH3OC(OH)CH2) and prop-1-ene-1,3-diol (HOCH2CHCHOH)) via keto-enol tautomerization. To the best of our knowledge, 1-methoxyethen-1-ol (CH3OC(OH)CH2) and prop-1-ene-1,3-diol (HOCH2CHCHOH) are experimentally identified for the first time. Our findings help to constrain the formation mechanism of hydroxyacetone and methyl acetate detected within star-forming regions and suggest that the hitherto astronomically unobserved isomer 3-hydroxypropanal and its enol tautomers represent promising candidates for future astronomical searches. These enol tautomers may contribute to the molecular synthesis of biologically relevant molecules in deep space due to their nucleophilic character and high reactivity.