Studied On Synthesis Of Anew Mesoporous Molecular Sieve And Its Catalytic Liquefaction Of Lignin

Lignin is a natural amorphous high-molecular polymer which acts as the essential glue to make plants structural integrity. With its unique physical structure and chemical properties, especially as the major aromatic resource, the comprehensive utilization of lignin would be particularly important.Catalytic liquefaction of lignin is the main way that lignin macromolecule compounds are cracked to small molecular platform chemical. Therefore, choosing the appropriate catalyst is especially important.In this paper, three different composition types mesoporous molecular sieve, the silicatealumino, silicatealuminotin and silicatealuminozirconium composition molecula sieves, are synthesized with crystal seed director route in traditional hydrothermal system, ethanol-water system, ionothermal system, respectively. The catalystic activity of these new synthesized mesoporous molecular sieves is studied on the catalytic liquefaction of lignin. The results are as follows:Silicatealumino mesoporous molecular sieves, MAS-7(1)(Si/Al=10/1), which is synethesized in ethanol-water system (CH3CH2OH/HCI=1), is of the best catalystic activity on the catalytic liquefaction of lignin. On the optimized conditions, liquefied rate of lignin can reach up to69%and the main production is the high veratric acid and homovanillic acid.Silicatealuminotin mesoporous molecular sieve, Sn-ILD-IL-28(Si/Al/Sn=20:1:1), which is synthesized in acidic ionic liquid system, is of the best catalystic activity on the catalytic liquefaction of lignin. On the optimized conditions, liquefied rate of lignin can reach up to62%and the main production is the phenol and ethyl vanillate.Silicatealuminozirconium mesoporous molecular sieves, Zr-JIL-SIL (Si/Al/Zr=20:1:1), which is synthesized in basic and acidic ionic liquid system, is of the best catalystic activity on the catalytic liquefaction of lignin. On the optimized conditions, liquefied rate of lignin can reach up to60%and the main production is the high veratric acid and homovanillic acid. The three mesoporous molecular sieves are characterized by N2ad/de, EDS and X-ray and so on. The results show that MAS-7(1) has better mesoporous structure and water thermal stability than traditional hydrothermal synthesis of MAS-7; in the ionothermal system, the tin and zirconium are successfully doped in the molecular sieves, which is unattainable for the traditional hydrothermal method.Ionothermal system can avoid high pressure reaction conditions for synthesis of mesoporous molecular sieves and contribute to metal heteroatom entering into the structure of mesoporous molecular sieves. Especially for the pure acidic ionic liquid system, the ionic liquids can easily recycled and lowly consumed, which provides a new way for future research.