Ling Ding, Lou Gao, Di Pan, Ke Du, Jiayu Yu, Wanyi Li, Yahong Zhang, Yi Tang
{"title":"利用形状选择性 H-Beta 沸石减少外消旋乳酸生成中乳酸","authors":"Ling Ding, Lou Gao, Di Pan, Ke Du, Jiayu Yu, Wanyi Li, Yahong Zhang, Yi Tang","doi":"10.1039/d4cy01046a","DOIUrl":null,"url":null,"abstract":"The utilization of racemic lactic acid (<em>rac</em>-LA) produced <em>via</em> chemocatalytic conversion for polylactic acid (PLA) synthesis remains limited due to the formation of undesired mesomeric lactide (<em>meso</em>-LD), a by-product that arises during the conversion process. This study proposes the use of shape-selective H-Beta zeolite to reduce the formation of <em>meso</em>-LD in lactide (LD) by leveraging its selectivity towards different lactic dimers (L<small><sub>2</sub></small>A) in a one-step catalytic conversion of <em>rac</em>-LA to LD. Experimental results from various LA solutions with different L<small><sub>2</sub></small>A content indicate that the L<small><sub>2</sub></small>A content is critical for maximizing the selectivity of racemic lactide (<small>D</small>/<small>L</small>-LD), thus confirming the shape-selective nature of H-Beta zeolite towards L<small><sub>2</sub></small>A. Additionally, it is found that increasing the reaction temperature and employing structurally reconstructed H-Beta zeolite with more regularized channels as a catalyst can further decrease <em>meso</em>-LD formation, and a LD yield of 60% with a <small>D</small>/<small>L</small>-LD/<em>meso</em>-LD ratio of 2.26 can be achieved under optimal catalyst and reaction conditions. Despite the coexistence of <small>D</small>/<small>L</small>-LD and <em>meso</em>-LD in the final product, this study marks a significant step towards controlling the stereoisomer distribution of LD synthesized from <em>rac</em>-LA derived from chemical conversion.","PeriodicalId":66,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":4.4000,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Reducing meso-lactide formation from racemic lactic acid using shape-selective H-Beta zeolite\",\"authors\":\"Ling Ding, Lou Gao, Di Pan, Ke Du, Jiayu Yu, Wanyi Li, Yahong Zhang, Yi Tang\",\"doi\":\"10.1039/d4cy01046a\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The utilization of racemic lactic acid (<em>rac</em>-LA) produced <em>via</em> chemocatalytic conversion for polylactic acid (PLA) synthesis remains limited due to the formation of undesired mesomeric lactide (<em>meso</em>-LD), a by-product that arises during the conversion process. This study proposes the use of shape-selective H-Beta zeolite to reduce the formation of <em>meso</em>-LD in lactide (LD) by leveraging its selectivity towards different lactic dimers (L<small><sub>2</sub></small>A) in a one-step catalytic conversion of <em>rac</em>-LA to LD. Experimental results from various LA solutions with different L<small><sub>2</sub></small>A content indicate that the L<small><sub>2</sub></small>A content is critical for maximizing the selectivity of racemic lactide (<small>D</small>/<small>L</small>-LD), thus confirming the shape-selective nature of H-Beta zeolite towards L<small><sub>2</sub></small>A. Additionally, it is found that increasing the reaction temperature and employing structurally reconstructed H-Beta zeolite with more regularized channels as a catalyst can further decrease <em>meso</em>-LD formation, and a LD yield of 60% with a <small>D</small>/<small>L</small>-LD/<em>meso</em>-LD ratio of 2.26 can be achieved under optimal catalyst and reaction conditions. Despite the coexistence of <small>D</small>/<small>L</small>-LD and <em>meso</em>-LD in the final product, this study marks a significant step towards controlling the stereoisomer distribution of LD synthesized from <em>rac</em>-LA derived from chemical conversion.\",\"PeriodicalId\":66,\"journal\":{\"name\":\"Catalysis Science & Technology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.4000,\"publicationDate\":\"2024-09-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Catalysis Science & Technology\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1039/d4cy01046a\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Catalysis Science & Technology","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4cy01046a","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Reducing meso-lactide formation from racemic lactic acid using shape-selective H-Beta zeolite
The utilization of racemic lactic acid (rac-LA) produced via chemocatalytic conversion for polylactic acid (PLA) synthesis remains limited due to the formation of undesired mesomeric lactide (meso-LD), a by-product that arises during the conversion process. This study proposes the use of shape-selective H-Beta zeolite to reduce the formation of meso-LD in lactide (LD) by leveraging its selectivity towards different lactic dimers (L2A) in a one-step catalytic conversion of rac-LA to LD. Experimental results from various LA solutions with different L2A content indicate that the L2A content is critical for maximizing the selectivity of racemic lactide (D/L-LD), thus confirming the shape-selective nature of H-Beta zeolite towards L2A. Additionally, it is found that increasing the reaction temperature and employing structurally reconstructed H-Beta zeolite with more regularized channels as a catalyst can further decrease meso-LD formation, and a LD yield of 60% with a D/L-LD/meso-LD ratio of 2.26 can be achieved under optimal catalyst and reaction conditions. Despite the coexistence of D/L-LD and meso-LD in the final product, this study marks a significant step towards controlling the stereoisomer distribution of LD synthesized from rac-LA derived from chemical conversion.
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