Insight into the Chemical Complexity of Soluble Portions from Cornstalk Methanolysis

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• 作者：Hong-Lei Yan ; Zhi-Min Zong ; Zhan-Ku Li ; Jiao Kong ; Quan-Xi Zheng ; Mei-Xia Zhao ; Yan Li ; Xian-Yong Wei
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：April 21, 2016
• 年：2016
• 卷：30
• 期：4
• 页码：3020-3029
• 全文大小：622K
• 年卷期：0
• ISSN：1520-5029

文摘

Cornstalk was subjected to methanolysis in the presence of NaOH at 220–320 °C to afford soluble portions (SPs) 1–5 (SP₁–SP₅) and an inextractable portion (IEP). The maximum total yield (ca. 51%) of SPs was acquired at 300 °C with the same mass of NaOH and cornstalk. Under the same conditions, SP₁ has the highest yield, followed by SP₅ and SP₂. The relatively volatile and less polar species in the resulting SPs and IEP were identified with a gas chromatograph/mass spectrometer (GC/MS). The polar species in SP₁, SP₂, and SP₅ were further analyzed with a negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (FTICRMS). The analysis with GC/MS shows that phenolic compounds and alcohols are the dominant group components in SP₁ and SP₂, respectively, while the predominant compounds in esterified SP₃–SP₅ and IEP are esters. According to analysis with FTICRMS, thousands of compounds were detected in SP₁, SP₂, and SP₅. Most of the compounds are O_n (n = 1–10) class species with double bond equivalent (DBE) values of 1–14 and carbon atom numbers of 5–35. The most abundant class species in SP₁, SP₂, and SP₅ are O₃, O₃, and O₈, respectively. SP₁ and SP₂ are rich in O₂–O₄ class species with DBE values of 5–8, which may be attributed to lignin-derived compounds. Different from SP₁ and SP₂, SP₅ has relatively high contents of O₅–O₁₀ class species, corresponding to various acidic species. In addition, N₁O_n (n = 0–8) class species with DBE values of 3–14 were also identified, which should contain a pyrrole ring as the parent structure.