The molecular structure of biomass and coal-based important platform compounds is rich in "carbon" and "oxygen". Researching new technical routes to prepare important oxygen-containing compounds can improve atom utilization and improve the original production process, which is complex and easy to cause environmental problems. pollution, high energy consumption and other shortcomings. The Green Chemistry Catalysis Research Group of the Qingdao Institute of Energy has carried out basic applied research on new technical routes for oxygenated compounds, regulated the key reaction trends of a series of small molecule platform compounds in coupling reactions, and achieved the integration of the innovation chain and the industrial chain. A series of research progresses have been made.
1,3-propanediol is often used as a monomer for the synthesis of polyester, polyether, etc., and can also be used in cosmetics, pharmaceuticals and other industries. In recent years, 1,3-propanediol, as the main raw material of a new type of polyester, polytrimethylene terephthalate (PTT), has attracted much attention due to the development of PTT. At present, the main production processes of 1,3-propanediol include ethylene oxide carbonylation, acrolein hydration hydrogenation and biological fermentation. Their production processes and costs directly affect the industrial production and promotion of PTT. The research team used cheap and easily available formaldehyde and acetaldehyde as raw materials, and under the action of a solid acid-base catalyst, directly prepared the key intermediate 3-hydroxypropionaldehyde in a one-step reaction, and then hydrogenated it to prepare 1,3-propanediol. The process route is simple , the reaction conditions are mild and the atom utilization rate is high (Figure 1). The optimized solid acid-base catalyst can inhibit the self-coupling reaction of acetaldehyde and the excessive coupling reaction of formaldehyde, and improve the selectivity of the formaldehyde-acetaldehyde cross-coupling reaction. By calculating reaction rates and activation energies, we gain a deeper theoretical understanding of competing reactions. Part of the research results were published in ACS Sustainable Chemistry & Engineering.
Figure 1. Controlled coupling hydrogenation of formaldehyde-acetaldehyde to prepare 1,3-propanediol
In addition, in the design of a new preparation route for 1,3-butanediol and allyl alcohol, the research team also achieved New progress (Figure 2). 1,3-Butanediol is mainly used in high-end daily chemicals, polyester and other industries. The currently commonly used preparation method has large changes in pH value during the reaction process, poor stability of key intermediates, corrosive reaction solutions, and the need to deal with salt content. Wastewater and other issues. The research team developed a continuous production process for 1,3-butanediol from acetaldehyde with independent intellectual property rights and applied for 5 invention patents. The first batch of new solid catalysts were developed and used in continuous fixed-bed reaction production equipment. During the production process, the material is neutral, and the reaction stops after leaving the catalyst. There is no need for acid-base neutralization and quenching reaction, which can effectively improve the directivity of conversion to 3-hydroxybutyraldehyde intermediate, and the material is non-corrosive and contains no salt. wastewater, simplifying the post-treatment process. Allyl alcohol is widely used in medicine, spices, synthetic resins and other fields, but its production has shortcomings such as cumbersome processes, high energy consumption, and heavy pollution. Using cheap and easily available low-carbon alcohols as raw materials, developing a new reaction route to prepare allyl alcohol can reduce costs, reduce energy consumption, and achieve green and efficient production. The research team achieved highly selective preparation of allyl alcohol by constructing a multifunctional composite metal oxide catalyst, and promoted the selective hydrogenation of carbonyl groups by regulating the distribution and surface concentration of Lewis acid-base pairs in the composite metal oxide catalyst. Further improve the selectivity of the series catalytic reaction. Based on this catalytic system, a new reaction route for direct dehydrogenation and dehydration of methanol to α-methylene to prepare allyl alcohol has been applied for 5 invention patents, and some of the research results were published in Applied Catalysis A, General.
Figure 2. Development of industrial catalysts for 1,3-butanediol and comparison of direct α-methyleneation routes of methanol
This work was funded by the National Natural Science Foundation of China, the Natural Science Foundation of Shandong Province, and the internal deployment project of the Qingdao Energy Institute. Cooperating with large enterprises such as Yanchang and Haike, we have achieved the above series of research progress. In the follow-up work, the research team will further elucidate the mechanism of directional coupling reactions, regulate product distribution, expand the reaction system, develop green and efficient new methods of material conversion, extend the basic chemical industry chain, and provide support for major projects such as the dual-carbon strategy. Technical support is required.
