The research team of Zheng Anmin from Wuhan Institute of physics, Chinese Academy of Sciences has made progress in the field of 31P probe molecular NMR technology to characterize the acid properties of solid acid catalytic materials

Recently, the research team of Zheng Anmin, Wuhan Institute of physics and mathematics, Chinese Academy of Sciences, has made new progress in the application research of 31 P-NMR probe molecular technology in acid characterization The relevant research results are published online in J am Chem SOC (DOI: 10.1021 / JACS 8b04819) Acid catalysis is one of the most important catalytic reactions in modern chemical industry Its catalytic performance is closely related to its acidity It has become an inevitable trend to replace the corrosive and polluting liquid acid catalyst with the environmental friendly solid acid catalyst represented by molecular sieve Compared with the acid characterization of liquid acid catalyst, the accurate measurement of the structure and acid properties of the active center of solid acid catalyst has always been a challenging problem In the past 10 years, the research team has focused on the development and application of NMR probe molecular technology in the field of acid characterization, and established a quantitative relationship between the strength of solid acid and Lewis acid and a series of probe molecular chemical shifts, such as deuterium pyridine, trimethylphosphine oxide, trimethylphosphine, acetone, etc., for the probe molecular NMR Methods a scale for quantitative characterization of solid acid strength was provided, and the international peers confirmed the uniqueness, reliability, accuracy and practicability of the NMR acid scale established by them with the descriptions of "unique", "reliable", "versatile" and "practical" Recently, team members have broken through the bottleneck that conventional 1H and 27Al NMR can't directly observe the three coordinated non framework aluminum species by using the molecular NMR technology of phosphine probe For the first time, trimethylphosphine (TMP) probe molecule and 2D 31p-31p NMR method were used to determine the structure of three coordinated non framework aluminum species with super acidity in USY molecular sieve, which is commonly used in industry The spatial interaction network between acids and the catalytic evaluation experiments show that the three coordinated aluminum species have excellent catalytic activity in the isomerization of glucose Furthermore, with the help of theoretical calculation, the origin, local fine structure and electronic structure of the three coordinated aluminum outside the framework are clearly described These results deepen people's understanding of acid center structure and acid catalytic reaction mechanism of molecular sieve, and provide theoretical guidance for the synthesis, design and modification of industrial molecular sieve catalyst Postdoctoral yixianfeng is the first author of the work, and the contact person is Zheng Anmin This work is supported by NSFC, Chinese Academy of Sciences and Hubei Provincial Department of science and technology, and also assisted by Peking University, Dalian University of technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Taiwan Institute of atomic and Molecular Sciences In addition, the research team has made new progress in the mechanism of the first carbon bond formation in the methanol conversion reaction catalyzed by acid in molecular sieve and Lewis acid It was found that the non skeleton aluminum species with catalytic activity in different types of molecular sieves have different structures and different reaction paths The results were published on the cover of the Royal Society of Chemistry Journal Chem Sci (DOI: 10.1039/C8SC02302F).