褐煤选择性氧化制羧基化学品

Selective oxidation of lignite to carboxyl chemicals

褐煤选择性氧化制羧基化学品是其高效利用的一种重要途径.目前,褐煤氧化制化学品的方法主要包括硝酸氧化法、次氯酸钠氧化法、双氧水氧化法、钌离子氧化法、碱-氧气氧化法、催化氧气氧化法以及其他氧化法等.采用不同的氧化方法对褐煤进行氧化,可能得到组成与分布均存在较大差别的氧化产物.但所有的氧化产物均是一种羧基化学品的混合物,需要进行分离纯化.因此,研究者对不同类型羧酸混合物的分离也进行了大量研究.本文从反应和机理方面综述了褐煤氧化制备羧基化学品的不同方法及其特点,分析了不同氧化方法存在的问题,介绍了产物羧酸混合物分离的研究及其存在的问题,尝试提出了褐煤选择性氧化制羧基化学品研究的进一步发展方向.

Selective oxidation of lignite to carboxyl chemicals is an important way for the utilization of lignite in a clean and efficient manner. At present, the methods of lignite oxidation to carboxyl chemicals include nitric acid oxidation,sodium hypochlorite oxidation, hydrogen peroxide oxidation, ruthenium-ion-catalyzed oxidation, alkali-oxygen oxidation, catalytic oxygen oxidation and other oxidation. Different methods of lignite oxidation may result in different carboxyl chemicals in compositions and yields. However, the oxidation product is a mixture including several carboxyl chemicals and needs to be separated and purified for further utilization. Therefore, researchers have also studied the separation of carboxylic acids using different ways. In this review, first, different methods of lignite oxidation and their mechanism of lignite oxidation are introduced, and the properties and the problems of the oxidation methods are analyzed. Second, the extraction of carboxylic acids in reaction solutions and the separation of carboxylic acid mixtures and the existing problems are also reviewed and discussed. Although many efforts have been paid to the selective oxidation of lignite to carboxyl chemicals, many problems still exist in the ways to industrial applications.Therefore, finally, the challenges and possible future developments in selective oxidation of lignite to carboxyl chemicals are analyzed and outlined.