Nakamura Manami, Islam Md Saidul, Rahman Mohammad Atiqur, Nahar Rabin Nurun, Fukuda Masahiro, Sekine Yoshihiro, Beltramini Jorge N, Kim Yang, Hayami Shinya
Department of Chemistry, Graduate School of Science and Technology, Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan
Institute of Industrial Nanomaterials (IINa), Kumamoto University 2-39-1 Kurokami, Chuo-ku Kumamoto 860-8555 Japan.
RSC Adv. 2021 Oct 26;11(55):34558-34563. doi: 10.1039/d1ra04426e. eCollection 2021 Oct 25.
The viability of biorefining technology primarily depends on the facile cellulose conversion route with adequate conversion efficiency. Here we have demonstrated the microwave-assisted hydrolysis of cellulose to glucose using polyoxometalate (POM) clusters as acid catalysts. Two different types of POM, including Wells-Dawson and Keggin were justified as catalysts in the cellulose conversion process. In particular, the cellulose to glucose catalytic conversion using Wells-Dawson type POMs has not been reported to date. Also, even though there have been some previous reports about the catalytic biomass conversion of Keggin type POMs, the systematic study to optimize the conversion efficiency in terms of catalyst amount, reaction temperature, reaction time, and the amount of solvent is lacking. Under the experimental conditions employed, the Keggin-type catalyst showed higher cellulose conversion and glucose yield than the Wells-Dawson-type catalyst. Furthermore, the cellulose conversion efficiency and glucose yields were optimized by tuning the reaction conditions including temperature, reaction time, and the amount of solvent. Under optimized conditions, the Keggin-type POM catalyst shows a remarkably high glucose yield of 77.2% and a cellulose conversion of 90.1%. The unique complex properties of the POM catalyst, including being (i) strong acids with extremely high Brønsted and Lewis acidity and (ii) efficient microwave adsorbants which enhanced interaction between substrate and the catalyst can be attributed to the outstanding efficacy of the conversion process.
生物精炼技术的可行性主要取决于具有足够转化效率的简便纤维素转化途径。在此，我们展示了使用多金属氧酸盐（POM）簇作为酸催化剂，通过微波辅助将纤维素水解为葡萄糖。两种不同类型的POM，包括韦尔斯-道森型和凯gin型，被证明可作为纤维素转化过程中的催化剂。特别是，迄今为止尚未报道使用韦尔斯-道森型POM将纤维素催化转化为葡萄糖的情况。此外，尽管之前有一些关于凯gin型POM催化生物质转化的报道，但缺乏从催化剂用量、反应温度、反应时间和溶剂量方面优化转化效率的系统研究。在所采用的实验条件下，凯gin型催化剂比韦尔斯-道森型催化剂表现出更高的纤维素转化率和葡萄糖产率。此外，通过调节包括温度、反应时间和溶剂量在内的反应条件，优化了纤维素转化效率和葡萄糖产率。在优化条件下，凯gin型POM催化剂显示出高达77.2%的葡萄糖产率和90.1%的纤维素转化率。POM催化剂独特的复合性质，包括（i）具有极高布朗斯特和路易斯酸度的强酸，以及（ii）增强底物与催化剂之间相互作用的高效微波吸附剂，可归因于转化过程的出色效果。
