Hydrothermal carbonization(HTC) is a valuable approach to convert furfural residue(FR) into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains...Hydrothermal carbonization(HTC) is a valuable approach to convert furfural residue(FR) into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques(~1H and ^(13)C NMR,~1H-~1H COSY and ~1H-^(13)C HSQC etc.) especially 1D selective gradient total correlation spectroscopy(TOCSY NMR) were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions(180-240 ℃ at 8 h, and 1-24 h at 240 ℃) was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies.展开更多
基金Supported by Shanxi Scholarship Council of China (2015-123)the Natural Science Foundation of China (51602322)the Key Research and Development Program of Shanxi Province (International Cooperation) (201703D421041) for financial support
文摘Hydrothermal carbonization(HTC) is a valuable approach to convert furfural residue(FR) into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques(~1H and ^(13)C NMR,~1H-~1H COSY and ~1H-^(13)C HSQC etc.) especially 1D selective gradient total correlation spectroscopy(TOCSY NMR) were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions(180-240 ℃ at 8 h, and 1-24 h at 240 ℃) was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies.
