Abstract Direct conversion of raw biomass to fine chemicals is of significant conceptual and practical interest. Up to now, the direct conversion of raw biomass to fine chemicals is still a big challenge. The oxidation of biomass to formic acid (FA) and acetic acid (AA) is a promising industrial process in the future. In this work, we reported that a binary catalyst system of Keggin-type heteropoly acid H 5 PV 2 Mo 10 O 40 + H 2 SO 4 was efficient to directly convert corn cob, a highly abundant renewable agricultural waste, to FA and AA using O 2 as the oxidant in aqueous solutions. The effects of catalyst amount, H 2 SO 4 concentration, reaction temperature, reaction time and initial O 2 pressure on the conversions of corn cob were investigated. Under optimized reaction conditions, corn cob was transformed with a FA yield of 42.5% and an AA yield of 9.1% (based on carbon) after 30 min of reaction at 170 °C. In the oxidation, the pH of the aqueous solution plays a key role. The influences of pH on solid degradation, reaction pathway and oxidation of the components of corn cob were discussed. Hemicellulose is oxidized rapidly followed by partly oxidation of lignin, and cellulose is the most difficult converted part. Products FA and AA mainly come from polysaccharides (hemicellulose and cellulose) and pH has a major influence on cellulose. The recycling of the catalyst system is demonstrated and shows good reusability.

中文翻译：

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O 2 催化氧化玉米芯生产甲酸和乙酸

摘要 将生物质直接转化为精细化学品具有重要的概念和实际意义。到目前为止，将生物质直接转化为精细化学品仍然是一个很大的挑战。将生物质氧化为甲酸（FA）和乙酸（AA）是未来很有前景的工业过程。在这项工作中，我们报道了 Keggin 型杂多酸 H 5 PV 2 Mo 10 O 40 + H 2 SO 4 的二元催化剂体系可有效地将玉米芯（一种高度丰富的可再生农业废物）直接转化为 FA 和 AA。 O 2 作为水溶液中的氧化剂。考察了催化剂用量、H 2 SO 4 浓度、反应温度、反应时间和初始O 2 压力对玉米芯转化率的影响。在优化的反应条件下，玉米芯以 42 的 FA 转化率转化。在 170 °C 下反应 30 分钟后，AA 产率为 5%，AA 产率为 9.1%（基于碳）。在氧化过程中，水溶液的pH值起着关键作用。讨论了pH值对玉米芯各组分固体降解、反应途径和氧化的影响。半纤维素被迅速氧化，其次是木质素的部分氧化，纤维素是最难转化的部分。产品 FA 和 AA 主要来自多糖（半纤维素和纤维素），pH 对纤维素有主要影响。催化剂体系的循环利用得到证明并显示出良好的可重复使用性。半纤维素被迅速氧化，其次是木质素的部分氧化，纤维素是最难转化的部分。产品 FA 和 AA 主要来自多糖（半纤维素和纤维素），pH 对纤维素有主要影响。催化剂体系的循环利用得到证明并显示出良好的可重复使用性。半纤维素被迅速氧化，其次是木质素的部分氧化，纤维素是最难转化的部分。产品 FA 和 AA 主要来自多糖（半纤维素和纤维素），pH 对纤维素有主要影响。催化剂体系的循环利用得到证明并显示出良好的可重复使用性。