| With the rapid development of China's modernization,the environmental damage caused by industrialization and other issues have gradually attracted people's attention.In the 1990s,the proposal and development of the concept of green chemistry were friendly solutions to a variety of challenges currently facing mankind,such as environmental pollution and energy shortages.As a cross-discipline,it has been rapidly applied in the fields of organic synthesis,catalytic conversion,biomedicine,analysis and detection.Traditional catalytic organic synthesis methods usually have the problems of expensive catalysts and unrecoverable catalysts,the use of toxic reagents,low product yields,and a large amount of toxic sewage produced after treatment,etc.Green organic catalysis is one of the effective methods to solve the various unfriendly existing in traditional synthetic chemistry.First,designing cheap,efficient,and recyclable catalysts is an advantageous way to reduce waste of resources and improve economic benefits.Secondly,the use of green solvent or solvent-free catalytic synthesis is a means to reduce environmental pollution and increase productivity.The research and design of a reasonable catalyst system and catalytic reaction process are particularly important in organic catalytic conversion.This subject starts with the design of a stable and efficient catalyst system,combined with the long-term contamination of the Lewis acid-surfactant catalyst proposed by Kobayashi.S,et al.,The rational use of silica loading and catalysis,and successful design a "Lewis acid-silica-surfactant" nanocomposite catalytic system was developed.Secondly,starting from the perspective of solvent-free green catalytic synthesis,combining the unique advantages of mechanical grinding chemistry,a composite catalyst was used to synthesize and prepare bis(indolyl)methane,Schiff base,and asymmetric indole methane derivatives.The efficient activity and stable recyclability of the catalyst were also investigated.In addition,based on the concept of solvent-free green synthesis,combined with solvothermal methods,a series of biologically active organic small-molecule compounds such as carbon-carbon,carbon-nitrogen,etc.were constructed by using no additional solvent and no catalyst.Finally,in view of the diversity of acid-catalyzed materials and the inherent relationship between catalytic materials and wastewater treatment,a carbon nitride-based composite photocatalyst material was designed and prepared for the study of degradation and treatment of wastewater containing dyes.The catalytic activity and stability of sewage such as alizarin red,basic fuchsin and acid fuchsin effectively revealed the structure-effect relationship between catalyst and dye wastewater,and obtained meaningful results.The main contents of the paper include:(1)To build a stable,efficient nano-catalyst and a greener,cleaner catalytic reaction process.The rational design and successful preparation of a "Lewis acid-silica-surfactant" composite catalyst system(LASSC catalyst System).The SEM,HRTEM,XPS,IR,and TGA characterization methods revealed the existence of-Si-O-Al-,-OH-Al-and other multiple catalytic active groups in the composite AlCl3·6H2O-SiO2-SDS catalyst system.Among them,the Lewis acid metal active center plays a leading role in the catalytic system;the weak catalytic effect of silica and the coordination effect of the surfactant and the metal center play a supporting role.Under solvent-free mechanical milling,a series of bis(indolyl)methane compounds with yields of 71%to 99%were prepared using an optimized composite AlC13·6H2O-SiO2-SDS catalyst in 15 to 35 minutes.The catalytic reaction process and post-treatment are simple and clean.The catalyst still maintains efficient catalytic activity and cycle time after repeated use for more than 10 times.The excellent catalytic performance and cycle life are attributed to the three components in the LASSC catalytic system which form cross-linked composite nanofiber structures through intermolecular interactions and coordination interactions,which have stable active center groups and are not easy to decompose.Through in situ capture of intermediate experiments,it was revealed that 3-indole aromatic alcohol is a key step in the indole methylation reaction.In addition,The LASSC catalyst system was successfully applied to the "one-pot method" for the synthesis of asymmetric indole methane derivatives with optical rotation properties,and the target product was obtained in a yield of 72%to 92%.The unique structure and activity of the catalyst are still maintained,and the catalytic activity does not decrease significantly after repeated use 8 times.In summary,the results show that the LASSC system has proven to be a cheap,green and efficient catalyst that promotes the electrophilic activation of aldehydes.Compared with the reported acid catalytic systems,the solventless catalytic system not only makes product separation easier,but also has higher catalytic activity,stability and environmental friendliness,especially for inhibiting and reducing the production of toxic surfactant wastewater.etc.(2)The goal is to design solvent-free green synthesis of biologically active organic molecules.By using solvothermal means,under the conditions of no solvent and no catalyst,the preparation of indole methane molecules,quinazolinone,xanthene and other biologically active compounds has been achieved.The green-catalyzed reaction processes of carbon-carbon,carbon-nitrogen,etc.in the absence of solvents and catalysts have been successfully constructed.The yield of all compounds has remained above 80%,and the operation process and post-treatment are simpler and environmentally friendly.Importantly,this not only effectively achieves resource conservation and reduction of environmental pollution from organic reagents from the source,but also facilitates quantitative preparation,which fully meets the development and requirements of green chemistry.(3)A series of carbonitride-based composite photocatalytic materials were designed and prepared with the goal of degrading and treating dye wastewater.The SEM,HRTEM,XRD,UV-vis-DRS,and PL characterization methods revealed that protonated g-C3N4/?-SiC has a high specific surface area.The g-C3N4 and nano ?-SiC form an effective heterojunction,which enhances the photo-generated electron-hole separation ability.UV-vis-DRS analysis showed that the protonated composite effectively increased the absorption of visible light,and at the same time,the migration rate of photo-generated carriers was improved.In addition,the material is used for photocatalytic degradation alizarin red,basic fuchsin,acid fuchsin and other dye wastewaters were investigated for photodegradation performance of the catalyst.The results showed that the photodegradation efficiency of the sample P-g-C3N4/?-SiC to sewage such as alizarin red,basic fuchsin,and acid fuchsin was 99%,89%,and 74%in 90 minutes.The catalytic performance of the catalyst P-g-C3N4/?-SiC is better than that of the sample P-g-C3N4/?-SiC.In addition,the P-g-C3N4/?-SiC catalyst has good stability and can be reused many times in the photocatalytic degradation of sewage without significant catalytic activity.In addition,it was proved through active species capture experiments that superoxide radical(·O2-)is the main active species in which P-g-C3N4/?-SiC participates in the photocatalytic reaction.It was confirmed by GC-MC that the final degradation product of Alizarin Red wastewater is mainly phthalic acid. |
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