Production of Valuable Chemicals from Renewable Resources through a New Liquid Phase Oxidation Method.

提出了一种新的氧化降解方法，用于从油棕壳废料中分离半纤维素、纤维素和木质素，并将其转化为有价值的化学品。该方法基本上是一个两步过程，即在180 ℃的热水中预处理的贝壳在60 ℃下用30%的H_2O_2在常压下氧化（第一阶段氧化），有或没有Fe催化剂。为了提高产物的产率和选择性，在芬顿试剂存在下，在25 ℃下对从第一阶段氧化获得的水溶性组分进行第二阶段氧化。通过热水处理，棕榈油壳中的半纤维素被成功地回收为纤维素，留下木质素和纤维素。通过第一段氧化，木质素在没有Fe催化剂的情况下被转化为含有HCOOH和CH_3COOH等小分子脂肪酸的水溶性化合物，并以22%的碳基收率回收了几乎纯的纤维素。后 关于我们 在第二段氧化中，小分子脂肪酸的产率达到30wt在上述方法中，找到另一种方法来利用以48%产率从油棕榈壳获得的水溶性化合物（WSL）作为中间体是有意义和有用的。由于水溶性有机化合物由部分氧化的木质素组成，因此它们的气化速率预期大于原始壳的气化速率。为了研究水溶性化合物作为气化原料的可能性，我们采用程序升温反应（TPR）方法，在氦气和氧气混合气体中比较了水溶性化合物、原始油棕壳（OPS）和热水预处理后的油棕壳（HTS）的气化速率。假设第一阶段和第二阶段气化分别对应于纤维素和木质素的气化。WSL在340 ℃以下迅速气化。原位红外光谱分析表明，木质素在气化前发生了交联反应，而WSL在气化过程中没有发生交联反应，生成芳环结构。随着转化率的提高，WSL的气化速率逐渐增大，当转化率为0.9时，WSL的气化速率是油棕壳的500倍，有望成为低品位资源转化为有价值化学品的新途径。少

A new oxidative degradation method was developed for separating hemicellulose, cellulose and lignin from an oil palm shell waste, and for converting them into valuable chemicals. The method is basically a two-step process, in which the shell pretreated in a hot water at 180 ℃ was oxidized with 30%-H_2O_2 at 60 ℃ (first stage oxidation) under ambient pressure with or without a Fe catalyst. To increase the product yield and selectivity, a second stage oxidation of the water-soluble components obtained from the first stage oxidation was also performed in the presence of the Fenton reagent at 25 ℃. Through the hot water treatment hemicellulose in the palm oil shell was successfully recovered as saccharides, leaving lignin and cellulose. Through the first stage oxidation without the Fe catalyst lignin was converted to water-soluble compounds containing small molecular weight fatty acids such as HCOOH and CH_3COOH, and almost pure cellulose was recovered in 22 % of yield on carbon basis. Aft … More er the second stage oxidation, the yield of small molecular weight fatty acids reached 30 wt.% on the oil palm shell basis.In the above method, it is meaningful and useful to find another methods to utilize the water-soluble compounds (WSL) that are obtained in 48 % yield as intermediates from the oil palm shell. Since the water-soluble organic compounds consist of partly oxidized lignin, their gasification rate is expected to be larger than the gasification rate of the original shell. We examined the possibility to utilize the water-soluble compounds as a feedstock for the gasification by comparing the gasification rates among WSL, the original oil palm shell (OPS) and the shell pretreated by hot water (HTS) using the so-called temperature-programmed reaction (TPR) method in a helium and oxygen gas mixture.The gasification of OPS and HTS proceeded in two steps. It is supposed that the first stage and the second stage gasifications correspond to the gasifications of cellulose and lignin, respectively. On the other hand, WSL was rapidly gasified below 340 ℃. From the in-situ FTIR measurements it was found that the lignin decomposed into cross-linked structure before being gasified for HTS.On the other hand, WSL was gasified without the cross-linking reaction developing aromatic ring structure. The gasification rate of WSL increased with the progress of conversion and was 500 times larger than that of the oil palm shell at the conversion of 0.9.Thus, the proposed method was expected to be a new route for converting low grade resources into valuable chemicals. Less