Production of Nitrogen‐Containing Compounds via the Conversion of Natural Microalgae from Water Blooms Catalyzed by ZrO 2

• Published in: ChemSusChem 2021-09, Vol.14 (18), p.3935-3944
• Main Authors: Liu, Li, Zhou, Yingdong, Guo, Lixian, Li, Guiying, Hu, Changwei
• Format: Article
• Language: English
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202101162

Utilizing the inherent high nitrogen content in natural microalgae to produce value‐added nitrogen‐containing compounds such as fatty amides and fatty nitriles is a promising method. Herein, a method for producing value‐added fatty amides and nitriles by liquefaction of natural microalgae from water blooms in n ‐heptane was developed. The effects of temperature, metal oxide catalyst (ZrO 2 , Al 2 O 3 , TiO 2 , ZnO, MgO, CaO), catalyst amount, and reaction time on the preparation of value‐added nitrogen‐containing compounds were studied. Under the optimized conditions (0.3 g ZrO 2 , 300 °C, 6 h), the total yield of fatty amides was 6.9 wt %, and the yield of fatty nitriles was 1.9 wt %. Compared with the results obtained in the absence of ZrO 2 , after adding ZrO 2 the total yield of fatty acids was reduced by 4.7 wt % (18.5 to 13.8 wt %), while the total yield of fatty amides only increased by 0.9 wt % (6.0 to 6.9 wt %) and fatty nitriles was increased by 1.5 wt % (0.4 to 1.9 wt %). Exploring the role of ZrO 2 by using model compounds (i. e., palmitic acid and palmitamide) revealed that ZrO 2 could promote the dehydration of fatty amides to form fatty nitriles, but had limited effect on the reaction of fatty acid and NH 3 .