(532dd) The Critical Role of Hidden Basic Sites of Na-ZSM-5 in the Dehydration of Lactic Acid

Due to environmental issues and regulations, research on biodegradable resins is being actively conducted around the world. Among them, PLA (Poly Lactic Acid), the main raw material of bioplastics, can be mass-produced by fermenting glucose in crops such as corn. In order to treat mass-produced lactic acid, the production of acrylic acid through dehydration is receiving great attention, and it has a high potential to replace acrylic acid produced from petroleum-derived. Many studies have been conducted on the dehydration reaction of lactic acid, and previous literature has suggested zeolite and calcium phosphate as the most promising catalyst system. Both catalysts are solid acid catalysts and have the advantage of tunable acid-base sites, but the conversion of unreacted intermediates to coking appears to be a major disadvantage. To solve this coking problem, the formation of proper base sites rather than acid sites is a key step for the selective dehydration of lactic acid to acrylic acid. It also has a great effect on extending the life-time of the catalyst. In this study, we report on the nature and critical roles of the “hidden basic sites” of the Na-ZSM-5 zeolites prepared by SDA-free method in the enhanced selectivity to acrylic acid.