基于新型多孔氢键-有机框架材料的乙烯/乙烷反转分离性能研究

乙烯/乙烷分离是工业上非常重要的分离过程，常用的低温精馏技术存在耗能高和成本高的缺陷，开发优先吸附乙烷的高性能乙烷类吸附分离材料有望解决这一难题。然而现有的这类材料数量极少，且存在分离选择性低和选择性/乙烷吸附量难以兼具（trade-off效应）的挑战性难题。本项目拟利用拓扑学规律和晶体工程策略，从原子分子尺度精确设计和调控一类新型多孔羧酸类氢键-有机框架材料（HOFs）并建立永久孔道；创新性地利用HOF材料天然的非极性孔道的结构优势，实现乙烯/乙烷的反转分离，解决构筑乙烷类分离材料难的问题；系统调控HOF材料的骨架结构、孔道大小、功能基团和结构贯穿等，提高材料对乙烯/乙烷反转分离的分离选择性和乙烷吸附量，以期实现高分离选择性的同时具有乙烷的高吸附量，克服trade-off效应；阐明乙烯/乙烷气体的吸附位点和分离机理，系统开发一类新型乙烷类分离材料。

Ethylene/ethane separation is of prime importance in the production of polymer-grade ethylene for industrial manufacturing. Traditional cryogenic distillation methods represent one of the most energy- and cost-intensive separation processes in the chemical industry. Development of new ethane-selective adsorbent materials with excellent separation performance has been considered to be capable of remarkably reducing the energy costs. However, construction of ethane-selective adsorbents is very challenging and only very few materials have been reported with low ethane/ethylene selectivity and the trade-off between selectivity and ethane uptake capacity. This project aims to develop a new type of ethane-selective adsorbents in order to improve the selectivity and uptake capacity simultaneously for inverse ethylene/ethane separation. Under the guidance of topology diagram that has been well realized in MOFs and COFs, we will precisely design and synthesize a series of new porous carboxylic hydrogen-bonded organic frameworks (HOFs) at the molecular level, wherein the networks and pores can be finely engineered by changing the knots and linker units of carboxylic building blocks. The natural nonpolar/inert pore surfaces within HOFs easily lead to the desired ethane-selective adsorbents. Through the crystal engineering or reticular chemistry strategy, we will systematically modulate the pore size, functionality and interpenetration in HOFs to optimize the selectivity and ethane adsorption simultaneously, thus overcoming the trade-off effect. The adsorption sites of ethylene and ethane molecules in these materials will be determined to elucidate the separation mechanism clearly.