Method for preparing aromatic compound through photocatalytic conversion of lignin and lignin-derived aryl ether

Abstract

The invention discloses a method for preparing an aromatic compound through photocatalytic conversion of lignin and lignin-derived aryl ether, and relates to the aromatic compound. A photocatalytic reaction is performed under a visible light condition so as to convert the lignin and the lignin-derived aryl ether into the aromatic compound. A sulfide semiconductor catalyst is added into a solution with the lignin or the lignin-derived aryl ether as a raw material, and after oxygen in a system is removed, a light source is turned on for the photocatalytic reaction so as to obtain the aromatic compound product. In visible light, preparation of the aromatic compound from the lignin and the lignin-derived aryl ether is achieved. According to the method, the visible light is used for the photocatalytic reaction, so that the method has the characteristics of environment friendliness, a mild reaction condition and the like. The method has the advantages as follows: the technical process is simple, the use of a sacrificial agent is avoided, the reaction is performed in an inert atmosphere, the catalyst is high in activity and stability, the aromatic compound product is unlikely to be excessively oxidized and is high in selectivity, the raw materials are low in price, and environment friendliness is ensured.

Description

technical field [0001] The invention relates to aromatic compounds, in particular to a method for preparing aromatic compounds by photocatalytic conversion of lignin and its derived aromatic ethers. Background technique [0002] Biomass is abundant on the earth, and the development of methods to convert biomass to high-value chemicals is of great significance to the establishment of a sustainable society. Lignin is an important part of biomass and the most important source of aromatic compounds in nature, which can be applied to the production of high value-added aromatic chemicals. For example, under appropriate conditions, after depolymerization of lignin, products such as vanillin, vanillyl ketone, isoeugenol, and homovanillic acid can be obtained. The structure of lignin is complex, and it is difficult to depolymerize. It lacks effective conversion and utilization methods, and less than 2% of the 150-180 million tons of industrial lignin produced in the world every year...

AI Technical Summary

Problems solved by technology

Mohamed Ksibi et al. reported that using nano-titanium dioxide to degrade lignin extracted from pulp black liquor under ultraviolet light, vanillin and vanillic acid were detected from the degradation products, but the yield of aromatic products was low, and the products were only prepared by GC-MS. Qualitative analysis (Journal of Photochemistry and Photobiology A: Chemistry 2003,154,211-218)

At present, most of the researches are focused on ultraviolet and aerobic conditions. Photocatalysts generate highly active oxygen species under light conditions, thereby degrading lignin, but it is difficult to make the product stay in aromatic compounds, and it is easy to over-oxidize

Although it has been reported in the literature that Pd / ZnIn 2 S 4 and TiO 2 Under the co-catalysis of two photocatalysts, the bond breaking of lignin-derived aromatic ethers can be achieved by switching between ultraviolet light and visible light, but the conversion of real lignin cannot be realized (ACS Catalysis 2016, 6, 7716-7721)

And this research must still use ultraviolet light and sacrificial agents, and the catalyst is prone to photocorrosion under aerobic conditions

However, under visible light, the use of heterogeneous photocatalysts to achieve high-selectivity conversion of lignin and its derivative aromatic ethers to prepare aromatic compounds has not been reported.

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