Abstract Cyclopentanone is an important platform chemical for various industrial syntheses. It has been recently reported as a major product in biomass cellulose-derived biofuels but has rarely been reported in geochemical research. We report here the abundant occurrence of cyclopentanone, 2-cyclopenten-1-one and their alkyl derivatives in pyrolysates of organic-rich shales. Closed system pyrolyses at temperatures from 290 °C to 350 °C have been carried out on thermally immature organic-rich shale samples of Ordovician and Devonian age from Canada. GC–MS analyses of the pyrolysates show that cyclopentanones, 2-cyclopenten-1-ones and phenols dominate over hydrocarbons in the low temperature hydrous pyrolysates, and their abundance relative to hydrocarbons decreases with increasing thermal maturation. However, these low molecular weight cyclic ketones are only minor components compared with hydrocarbons in anhydrous pyrolysates, indicating that water has played an important role in the formation of these oxygen-containing compounds. In addition, n-alkan-2-ones in the range of C6–C35 are also detected in the hydrous pyrolysates, but they are at much reduced concentrations compared with the cyclic ketones. The potential precursors in the shale and the likely chemical reaction mechanism for the formation of these cyclic ketones are discussed in detail in the paper.

中文翻译：

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环戊酮和 2-环戊烯-1-酮作为未成熟富含有机质页岩的含水热解的主要产物

摘要 环戊酮是各种工业合成的重要平台化学品。最近有报道称它是生物质纤维素衍生生物燃料的主要产品，但在地球化学研究中很少报道。我们在此报告了在富含有机质页岩的热解产物中大量存在的环戊酮、2-环戊烯-1-one 及其烷基衍生物。已在 290 °C 至 350 °C 的温度下对来自加拿大的奥陶纪和泥盆纪热未成熟的富含有机质页岩样品进行了封闭系统热解。热解产物的 GC-MS 分析表明，在低温含水热解产物中，环戊酮、2-环戊烯-1-酮和苯酚在碳氢化合物中占主导地位，并且它们相对于碳氢化合物的丰度随着热成熟度的增加而降低。然而，与无水热解产物中的碳氢化合物相比，这些低分子量环酮只是次要成分，表明水在这些含氧化合物的形成过程中发挥了重要作用。此外，在含水热解产物中也检测到 C6-C35 范围内的 n-alkan-2-ones，但与环酮相比，它们的浓度要低得多。论文中详细讨论了页岩中的潜在前体以及形成这些环酮的可能化学反应机制。但与环酮相比，它们的浓度要低得多。论文中详细讨论了页岩中的潜在前体以及形成这些环酮的可能化学反应机制。但与环酮相比，它们的浓度要低得多。论文中详细讨论了页岩中的潜在前体以及形成这些环酮的可能化学反应机制。