Styrene (ST) is one of the most important feedstocks in the petrochemical industry and must be separated from a mixture of ST and ethylbenzene (EB). While the current technology comprises the energy-intensive vacuum distillation process, energy-saving adsorptive separation can be an alternative for ST/EB separation. The potential of a series of isostructural metal-organic frameworks (MOFs), M-MOF-74 (M = Mg, Co, Cu, or Zn), featured by highly dense unsaturated metal sites were evaluated for use in ST/EB separation using liquid-phase adsorption experiments. While all four M-MOF-74 materials showed selective adsorption of ST over EB, Co-MOF-74 exhibited the highest ST/EB selectivity (6.9) and the largest ST uptake (2.5 mmol/g), which were superior to those of benchmark MOF materials. This can be explained by the preferential interaction between unsaturated Co²⁺ sites and unsaturated ST molecules. Moreover, Co-MOF-74 retained its adsorption performance, porosity, and structural integrity after three consecutive adsorption and desorption experiments. These findings suggest that creating high density of Co²⁺ sites within a proper pore size would be an efficient strategy for developing an adsorbent for ST/EB separation.

苯乙烯（ST）是石化工业中最重要的原料之一，必须从ST和乙苯（EB）的混合物中分离出来。尽管当前的技术包括高能耗的真空蒸馏过程，但节能的吸附分离可以替代ST / EB分离。评估了以高密度不饱和金属位点为特征的一系列同构金属-有机骨架（MOF）M-MOF-74（M = Mg，Co，Cu或Zn）的潜力，可用于ST / EB分离液相吸附实验。虽然所有四种M-MOF-74材料均显示出EB选择性吸附了ST，但Co-MOF-74表现出最高的ST / EB选择性（6.9）和最大的ST吸收（2.5 mmol / g），优于基准MOF材料。²⁺位和不饱和ST分子。此外，在连续三个吸附和解吸实验后，Co-MOF-74仍保留了其吸附性能，孔隙率和结构完整性。这些发现表明在合适的孔径内产生高密度的Co ²⁺位点将是开发用于ST / EB分离的吸附剂的有效策略。