Abstract Hydrothermal liquefaction (HTL) of biomass such as lignin could contribute to finding replacements for petroleum, both as a fuel and production of chemicals. The organic phase produced in formic acid assisted HTL of lignin has been extensively analyzed previously. The solid phase is routinely analyzed by elemental analysis, and the gas phase has also been studied. The aqueous phase, on the other hand, has received little attention so far and this paper aims to identify and quantify the organic compounds that remain in the aqueous phase after the workup of the organic phase. Using NMR with water suppression, this is achieved with simple sample preparation. The major components are identified using 2D NMR (HSQC spectra) together with proton spectra and 13C spectra as well as verification with standard samples. Their concentrations are determined based on 1H spectra with an added internal standard. An initial evaluation of the effect of temperature and catalyst in the formic acid assisted HTL is given to demonstrate the relevance of the approach. Methanol, formic acid, acetic acid, acetone, phenol, catechol, and dimethyl ether have been identified and quantified in aqueous samples from six different HTL-experiments. 76 %–86 % of the peak area of the proton spectra have been accounted for.

中文翻译：

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木质素水热液化水相的定量 NMR 分析

摘要 木质素等生物质的水热液化 (HTL) 有助于寻找石油的替代品，既可以作为燃料，也可以作为化学品的生产。在甲酸辅助木质素 HTL 中产生的有机相之前已被广泛分析。固相通常通过元素分析进行​​分析，气相也已被研究。另一方面，到目前为止，水相很少受到关注，本文旨在鉴定和量化有机相处理后残留在水相中的有机化合物。使用 NMR 和水抑制，这可以通过简单的样品制备来实现。主要成分使用 2D NMR（HSQC 光谱）、质子光谱和 13C 光谱以及标准样品验证进行鉴定。它们的浓度是根据 1H 光谱和添加的内标确定的。对甲酸辅助 HTL 中温度和催化剂的影响进行了初步评估，以证明该方法的相关性。甲醇、甲酸、乙酸、丙酮、苯酚、儿茶酚和二甲醚已在来自六个不同 HTL 实验的水性样品中得到鉴定和定量。质子光谱峰面积的 76%–86% 已被考虑在内。和二甲醚已在来自六个不同 HTL 实验的水性样品中得到鉴定和定量。质子光谱峰面积的 76%–86% 已被考虑在内。和二甲醚已在来自六个不同 HTL 实验的水性样品中得到鉴定和定量。质子光谱峰面积的 76%–86% 已被考虑在内。