Recent progress in adsorption and separation of xylene isomers

doi:10.11949/0438-1157.20231189

Abstract

Abstract:

The separation and purification of xylene isomers is one of the important processes in the petrochemical industry. However, the structures and properties of xylene isomers are extremely close. Conventional distillation and cryogenic crystallization separation methods have high energy consumption and low production efficiency. Simulated moving bed chromatography is the primary technology for separating xylene isomers, but zeolites as the adsorbents are insufficient in terms of adsorption capacity and separation selectivity. Metal-organic frameworks and supramolecular materials possess advantages such as flexible assembly, structural diversity, and adjustable properties. They can achieve highly efficient discrimination and separation of xylene isomers through the construction of polar pore environment and fine-turning of the size and shape of pore channels. This review summarizes the research progress of metal-organic frameworks and supramolecular materials in the adsorption and separation of xylene isomers, discusses the intrinsic mechanisms of xylene isomers' separation from aspects including electrostatic interactions, size sieving, and shape sieving. It also summarizes the problems and limitations of metal-organic frameworks in the field of xylenes separation and provides a prospective on future development directions.

Key words: adsorption, separation, adsorbents, xylene isomers, para-xylene, metal-organic frameworks

摘要：

二甲苯异构体的分离与纯化是石油化学工业的重要过程之一，但二甲苯异构体的结构和性质极其接近，常规精馏和深冷结晶法分离能耗高、生产效率低。模拟移动床色谱是主流的二甲苯异构体分离技术，但作为吸附剂的分子筛在吸附容量和分离选择性两方面均存在不足。金属有机框架和超分子材料具有组装自由、结构多样和性质可调等优点，可通过构建极性孔环境或精准设计孔道尺寸与形状实现二甲苯异构体的高效辨识与分离。本文综述了金属有机框架和超分子材料在二甲苯异构体吸附分离中的研究进展，从静电作用、尺寸筛分和形状筛分等方面探讨了二甲苯异构体分离的内在机制，总结了金属有机框架在二甲苯分离领域存在的问题和局限，并对未来发展方向进行了展望。

关键词: 吸附, 分离, 吸附剂, 二甲苯异构体, 对二甲苯, 金属有机框架

CLC Number:

TQ 241.1

Ying LIU, Fang ZHENG, Qiwei YANG, Zhiguo ZHANG, Qilong REN, Zongbi BAO. Recent progress in adsorption and separation of xylene isomers[J]. CIESC Journal, 2024, 75(4): 1081-1095.

刘莹, 郑芳, 杨启炜, 张治国, 任其龙, 鲍宗必. 二甲苯异构体吸附分离研究进展[J]. 化工学报, 2024, 75(4): 1081-1095.

Figures/Tables 11

Fig.1 Different types of MOFs for xylenes adsorptive separation

Table 1 Physical properties of C8 aromatic isomers［68-69］

C₈芳烃	沸点/K	凝固点/K	动力学直径/Å	三维尺寸/Å×Å×Å	三维尺寸纵横比	偶极矩/(10^-18esu·cm)	极化率/(10^-25 cm³)
PX	411.5	286.4	5.8	6.6×3.8×9.1	1.38	0.10	137~149
OX	417.6	248.0	6.8	7.3×3.8×7.8	1.07	0.64	141~149
MX	412.3	222.5	6.8	7.3×4.0×9.0	1.23	0.37	142
EB	409.4	178.2	5.8	6.6×5.3×9.4	1.42	0.59	142

Fig.2 Breakthrough curves of vapor-phase xylene mixtures on HKUST-1 and Ni2(dobdc) at 398 K

Fig.3 Vapor adsorption isotherms of C8 aromatics on Co2(dobdc) at 423 K (a), breakthrough curves of C8 aromatic vapor mixtures on Co2(dobdc) at 398 K (b), and structural distortion of Co2(dobdc) upon adsorption of OX (c)

Fig.4 Structure of MFM-300(M) (a), pore sizes of MFM-300(M) (b) and vapor-phase breakthrough curves of xylenes on MFM-300(M) (c)

Fig.5 Structure and vapor adsorption isotherms of C8 aromatics of sql-1-Co-NCS (a) and sql-1,3-Co-NCS (b)

Fig.6 Structure of MIL-47(V) (a) and MIL-53(Al) (b) after adsorbing xylene isomers

Fig.7 Structure of [Mn(dhbq)(H2O)2]（a）； Structures and distance between substituents of xylene isomers (b); Vapor adsorption isotherms and vapor-phase breakthrough curves on Mn(dhbq) (c); Binding sites of Mn(dhbq) for adsorbing xylene isomers(d)

Fig.8 Structures of the smallest assembly units of supramolecular materials

Table 2 Summary of xylene isomers separation performance of supramolecular materials

超分子材料	分类	吸附偏好	选择性	实验方法	文献
CC3	有机分子笼	PX	PX/OX=2.9^①, PX/MX=1.5^①	气相静态吸附	[13]
AZO-cage	有机分子笼	PX	PX/OX=15.6, PX/MX=10.9	气相静态吸附	[11]
AZO-cage	有机分子笼	PX	PX/OX=12.1, PX/MX=7.3	气相静态吸附	[11]
EtP5	有机分子大环	PX	PX/OX=1.9^①, PX/MX=2.1^①	气相静态吸附	[89]
EtP6	有机分子大环	PX	PX/OX=14.3^①, PX/MX=10.2^①	气相静态吸附	[89]
AgLClO₄	金属有机化合物	PX	PX/OX=20.3, PX/MX=5.4	气相静态吸附	[92]
AgLClO₄	金属有机化合物	PX	PX/OX=24.0, PX/MX=16.2	气相静态吸附	[92]
[Ni(NCS)₂(ppp)₄]	金属有机化合物	OX	OX/PX=40.5, OX/MX=34.2	气相静态吸附	[93]
[Cu₂(bitmb)₂Cl₄]	金属有机大环	PX	PX/OX=51.5, PX/MX=65.7	液相静态吸附	[94]
G₂NDS	氢键有机框架	PX	PX/OX=36.0, PX/MX=160.0	液相静态吸附	[95]

Fig.9 Separation selectivity comparison of PX, OX selective MOFs and supramolecular materials○calculated by gas-phase static adsorption data；△calculated by liquid-phase static adsorption data；□calculated by chromatography data；◇calculated by liquid-phase breakthrough curve； calculated by gas-phase breakthrough curve

References 96

1	Cannella W J. Kirk-othmer Encyclopedia of Chemical Technology[M]. New York: John Wiley & Sons Inc., 2005.
2	Yang Y X, Bai P, Guo X H. Separation of xylene isomers: a review of recent advances in materials[J]. Industrial & Engineering Chemistry Research, 2017, 56(50): 14725-14753.
3	Shi Q, Gonçalves J C, Ferreira A F P, et al. A review of advances in production and separation of xylene isomers[J]. Chemical Engineering and Processing - Process Intensification, 2021, 169: 108603.
4	Sholl D S, Lively R P. Seven chemical separations to change the world[J]. Nature, 2016, 532: 435-437.
5	Minceva M, Rodrigues A E. Understanding and revamping of industrial scale SMB units for p-xylene separation[J]. AIChE Journal, 2007, 53(1): 138-149.
6	Cheng L S, Johnson J A. Adsorbents with improved mass transfer properties and their use in the adsorptive separation of para-xylene: US8609925[P]. 2013-12-17.
7	杨彦强, 柏成钢, 王红超, 等. 对二甲苯吸附剂RAX-4000的工业应用特点[J]. 石油炼制与化工, 2023, 54(7): 41-45.
	Yang Y Q, Bai C G, Wang H C, et al. Commercial application of adsorbent RAX-4000[J]. Petroleum Processing and Petrochemicals, 2023, 54(7): 41-45.
8	Guisnet M, Gilson J P. Zeolites for Cleaner Technologies[M]. London: Imperial College Press, 2002.
9	Santos K A O, Dantas Neto A A, Moura M C P A, et al. Separation of xylene isomers through adsorption on microporous materials: a review[J]. Brazilian Journal of Petroleum and Gas, 2011, 5(4): 255-268.
10	Zhang Z Q, Peh S B, Kang C J, et al. Metal-organic frameworks for C6—C8 hydrocarbon separations[J]. EnergyChem, 2021, 3: 100057.
11	Moosa B, Alimi L O, Shkurenko A, et al. A polymorphic azobenzene cage for energy-efficient and highly selective p-xylene separation[J]. Angewandte Chemie International Edition, 2020, 59(48): 21367-21371.
12	Zhang G W, Emwas A H, Shahul Hameed U F, et al. Shape-induced selective separation of ortho-substituted benzene isomers enabled by cucurbit[7]uril host macrocycles[J]. Chem, 2020, 6(5): 1082-1096.
13	Mitra T, Jelfs K E, Schmidtmann M, et al. Molecular shape sorting using molecular organic cages[J]. Nature Chemistry, 2013, 5: 276-281.
14	Zhou Y, Zhang J L, Wang L, et al. Self-assembled iron-containing mordenite monolith for carbon dioxide sieving[J]. Science, 2021, 373(6552): 315-320.
15	Zhou H, Yi X F, Hui Y, et al. Isolated boron in zeolite for oxidative dehydrogenation of propane[J]. Science, 2021, 372(6537): 76-80.
16	Bellat J P, Simonot-Grange M H, Jullian S. Adsorption of gaseous p-xylene and m-xylene on NaY, KY, and BaY zeolites(1). Adsorption equilibria of pure xylenes[J]. Zeolites, 1995, 15(2): 124-130.
17	Minceva M, Rodrigues A E. Adsorption of xylenes on faujasite-type zeolite[J]. Chemical Engineering Research and Design, 2004, 82(5): 667-681.
18	Buarque H L B, Chiavone-Filho O, Cavalcante C L. Adsorption equilibria of C₈ aromatic liquid mixtures on Y zeolites using headspace chromatography[J]. Separation Science and Technology, 2005, 40(9): 1817-1834.
19	Moïse J C, Bellat J P. Effect of preadsorbed water on the adsorption of p-xylene and m-xylene mixtures on BaX and BaY zeolites[J]. Journal of Physical Chemistry B, 2005, 109(36): 17239-17244.
20	Daems I, Leflaive P, Méthivier A, et al. Influence of Si∶Al-ratio of faujasites on the adsorption of alkanes, alkenes and aromatics[J]. Microporous and Mesoporous Materials, 2006, 96(1/2/3): 149-156.
21	Kumar P, Kim D W, Rangnekar N, et al. One-dimensional intergrowths in two-dimensional zeolite nanosheets and their effect on ultra-selective transport[J]. Nature Materials, 2020, 19: 443-449.
22	Daramola M O, Burger A J, Pera-Titus M, et al. Xylene vapor mixture separation in nanocomposite MFI-alumina tubular membranes: influence of operating variables[J]. Separation Science and Technology, 2009, 45(1): 21-27.
23	Yuan W H, Lin Y S, Yang W S. Molecular sieving MFI-type zeolite membranes for pervaporation separation of xylene isomers[J]. Journal of the American Chemical Society, 2004, 126(15): 4776-4777.
24	Sakai H, Tomita T, Takahashi T. p-Xylene separation with MFI-type zeolite membrane[J]. Separation and Purification Technology, 2001, 25(1/2/3): 297-306.
25	Wang T, Lin E, Peng Y L, et al. Rational design and synthesis of ultramicroporous metal-organic frameworks for gas separation[J]. Coordination Chemistry Reviews, 2020, 423: 213485.
26	Freund R, Zaremba O, Arnauts G, et al. The current status of MOF and COF applications[J]. Angewandte Chemie International Edition, 2021, 60(45): 23975-24001.
27	Yang L F, Qian S H, Wang X B, et al. Energy-efficient separation alternatives: metal-organic frameworks and membranes for hydrocarbon separation[J]. Chemical Society Reviews, 2020, 49(15): 5359-5406.
28	He Y B, Zhou W, Qian G D, et al. Methane storage in metal-organic frameworks[J]. Chemical Society Reviews, 2014, 43(16): 5657-5678.
29	Verma G, Ren J Y, Kumar S, et al. New paradigms in porous framework materials for acetylene storage and separation[J]. European Journal of Inorganic Chemistry, 2021, 2021(44): 4498-4507.
30	Zhou S, Shekhah O, Ramírez A, et al. Asymmetric pore windows in MOF membranes for natural gas valorization[J]. Nature, 2022, 606: 706-712.
31	Chen K J, Madden D G, Mukherjee S, et al. Synergistic sorbent separation for one-step ethylene purification from a four-component mixture[J]. Science, 2019, 366(6462): 241-246.
32	Peng Y L, Wang T, Jin C N, et al. Efficient propyne/propadiene separation by microporous crystalline physiadsorbents[J]. Nature Communications, 2021, 12: 5768.
33	Liao P Q, Huang N Y, Zhang W X, et al. Controlling guest conformation for efficient purification of butadiene[J]. Science, 2017, 356(6343): 1193-1196.
34	Huang X, Jiang S Y, Ma D, et al. Molecular exclusion separation of 1-butene isomers by a robust metal-organic framework under humid conditions[J]. Angewandte Chemie International Edition, 2023, 62(31): e202303671.
35	Banerjee D, Simon C M, Elsaidi S K, et al. Xenon gas separation and storage using metal-organic frameworks[J]. Chem, 2018, 4(3): 466-494.
36	Niu Z, Fan Z W, Pham T, et al. Self-adjusting metal-organic framework for efficient capture of trace xenon and krypton[J]. Angewandte Chemie International Edition, 2022, 61(11): e202117807.
37	Pei J Y, Gu X W, Liang C C, et al. Robust and radiation-resistant hofmann-type metal-organic frameworks for record xenon/krypton separation[J]. Journal of the American Chemical Society, 2022, 144(7): 3200-3209.
38	Zheng F, Guo L D, Chen R D, et al. Shell-like xenon nano-traps within angular anion-pillared layered porous materials for boosting Xe/Kr separation[J]. Angewandte Chemie International Edition, 2022, 61(20): e202116686.
39	Wang S M, Mu X T, Liu H R, et al. Pore-structure control in metal-organic frameworks (MOFs) for capture of the greenhouse gas SF₆ with record separation[J]. Angewandte Chemie International Edition, 2022, 61(33): 2207066.
40	Xia W, Yang Y S, Sheng L Z, et al. Temperature-dependent molecular sieving of fluorinated propane/propylene mixtures by a flexible-robust metal-organic framework[J]. Science Advances, 2024, 10(3): eadj6473.
41	Wang H, Li J. Microporous metal-organic frameworks for adsorptive separation of C5—C6 alkane isomers[J]. Accounts of Chemical Research, 2019, 52(7): 1968-1978.
42	Zheng F, Guo L D, Chen R D, et al. Temperature-swing molecular exclusion separation of hexane isomers in robust MOFs with double-accessible open metal sites[J]. Chemical Engineering Journal, 2023, 460: 141743.
43	Lal B, Idrees K B, Xie H M, et al. Pore aperture control toward size-exclusion-based hydrocarbon separations[J]. Angewandte Chemie International Edition, 2023, 62(16): e202219053.
44	Guo F A, Wang J, Chen C L, et al. Linker vacancy engineering of a robust ftw-type Zr-MOF for hexane isomers separation[J]. Angewandte Chemie International Edition, 2023, 62(24): e202303527.
45	Han Y, Chen Y L, Ma Y J, et al. Control of the pore chemistry in metal-organic frameworks for efficient adsorption of benzene and separation of benzene/cyclohexane[J]. Chem, 2023, 9(3): 739-754.
46	Li W B, Wu Y, Zhong X F, et al. Fluorescence enhancement of a metal-organic framework for ultra-efficient detection of trace benzene vapor[J]. Angewandte Chemie International Edition, 2023, 62(24): e202303500.
47	He T, Kong X J, Bian Z X, et al. Trace removal of benzene vapour using double-walled metal-dipyrazolate frameworks[J]. Nature Materials, 2022, 21: 689-695.
48	Cui X L, Niu Z, Shan C, et al. Efficient separation of xylene isomers by a guest-responsive metal-organic framework with rotational anionic sites[J]. Nature Communications, 2020, 11: 5456.
49	Li X L, Wang J H, Bai N N, et al. Refinement of pore size at sub-angstrom precision in robust metal-organic frameworks for separation of xylenes[J]. Nature Communications, 2020, 11: 4280.
50	Idrees K B, Li Z, Xie H M, et al. Separation of aromatic hydrocarbons in porous materials[J]. Journal of the American Chemical Society, 2022, 144(27): 12212-12218.
51	Li L Y, Guo L D, Olson D H, et al. Discrimination of xylene isomers in a stacked coordination polymer[J]. Science, 2022, 377(6603): 335-339.
52	Yu L, Zhang J, Ullah S, et al. Separating xylene isomers with a calcium metal-organic framework[J]. Angewandte Chemie International Edition, 2023, 62(41): e202310672.
53	Zhou J Y, Ke T, Song Y F, et al. Highly efficient separation of C8 aromatic isomers by rationally designed nonaromatic metal-organic frameworks[J]. Journal of the American Chemical Society, 2022, 144(46): 21417-21424.
54	Gu Z Y, Jiang D Q, Wang H F, et al. Adsorption and separation of xylene isomers and ethylbenzene on two Zn-terephthalate metal-organic frameworks[J]. Journal of Physical Chemistry C, 2010, 114(1): 311-316.
55	Nicolau M P M, Bárcia P S, Gallegos J M, et al. Single- and multicomponent vapor-phase adsorption of xylene isomers and ethylbenzene in a microporous metal-organic framework[J]. Journal of Physical Chemistry C, 2009, 113(30): 13173-13179.
56	Huang L. Synthesis, morphology control, and properties of porous metal-organic coordination polymers[J]. Microporous and Mesoporous Materials, 2003, 58(2): 105-114.
57	Finsy V, Verelst H, Alaerts L, et al. Pore-filling-dependent selectivity effects in the vapor-phase separation of xylene isomers on the metal-organic framework MIL-47[J]. Journal of the American Chemical Society, 2008, 130(22): 7110-7118.
58	Alaerts L, Kirschhock C E A, Maes M, et al. Selective adsorption and separation of xylene isomers and ethylbenzene with the microporous vanadium(Ⅳ) terephthalate MIL-47[J]. Angewandte Chemie International Edition, 2007, 46(23): 4293-4297.
59	Finsy V, Kirschhock C E A, Vedts G, et al. Framework breathing in the vapour-phase adsorption and separation of xylene isomers with the metal-organic framework MIL-53[J]. Chemistry, 2009, 15(31): 7724-7731.
60	Alaerts L, Maes M, Giebeler L, et al. Selective adsorption and separation of ortho-substituted alkylaromatics with the microporous aluminum terephthalate MIL-53[J]. Journal of the American Chemical Society, 2008, 130(43): 14170-14178.
61	Zhang K, Lively R P, Zhang C, et al. Exploring the framework hydrophobicity and flexibility of ZIF-8: from biofuel recovery to hydrocarbon separations[J]. Journal of Physical Chemistry Letters, 2013, 4(21): 3618-3622.
62	Peralta D, Chaplais G, Paillaud J L, et al. The separation of xylene isomers by ZIF-8: a demonstration of the extraordinary flexibility of the ZIF-8 framework[J]. Microporous and Mesoporous Materials, 2013, 173: 1-5.
63	Polyukhov D M, Poryvaev A S, Sukhikh A S, et al. Fine-tuning window apertures in ZIF-8/67 frameworks by metal ions and temperature for high-efficiency molecular sieving of xylenes[J]. ACS Applied Materials & Interfaces, 2021, 13(34): 40830-40836.
64	van der Perre S, Van Assche T, Bozbiyik B, et al. Adsorptive characterization of the ZIF-68 metal-organic framework: a complex structure with amphiphilic properties[J]. Langmuir, 2014, 30(28): 8416-8424.
65	Gonzalez M I, Kapelewski M T, Bloch E D, et al. Separation of xylene isomers through multiple metal site interactions in metal-organic frameworks[J]. Journal of the American Chemical Society, 2018, 140(9): 3412-3422.
66	Peralta D, Barthelet K, Pérez-Pellitero J, et al. Adsorption and separation of xylene isomers: CPO-27-Ni vs HKUST-1 vs NaY[J]. Journal of Physical Chemistry C, 2012, 116(41): 21844-21855.
67	Mukherjee S, Joarder B, Manna B, et al. Framework-flexibility driven selective sorption of p-xylene over other isomers by a dynamic metal-organic framework[J]. Scientific Reports, 2014, 4: 5761.
68	Li J R, Kuppler R J, Zhou H C. Selective gas adsorption and separation in metal-organic frameworks[J]. Chemical Society Reviews, 2009, 38(5): 1477-1504.
69	Webster C E, Drago R S, Zerner M C. Molecular dimensions for adsorptives[J]. Journal of the American Chemical Society, 1998, 120(22): 5509-5516.
70	Gu Z Y, Yan X P. Metal-organic framework MIL-101 for high-resolution gas-chromatographic separation of xylene isomers and ethylbenzene[J]. Angewandte Chemie International Edition, 2010, 49(8): 1477-1480.
71	Jin Z, Zhao H Y, Zhao X J, et al. A novel microporous MOF with the capability of selective adsorption of xylenes[J]. Chemical Communications, 2010, 46(45): 8612-8614.
72	Lannoeye J, Van de Voorde B, Bozbiyik B, et al. An aliphatic copper metal-organic framework as versatile shape selective adsorbent in liquid phase separations[J]. Microporous Mesoporous Mater, 2016, 226: 292-298.
73	Li X F, Bian H, Huang W Q, et al. A review on anion-pillared metal-organic frameworks (APMOFs) and their composites with the balance of adsorption capacity and separation selectivity for efficient gas separation[J]. Coordination Chemistry Reviews, 2022, 470: 214714.
74	Yang L P, Liu H B, Xing J C, et al. Separation of xylene isomers in the anion-pillared square grid material SIFSIX-1-Cu[J]. Chemistry, 2021, 27(20): 6187-6190.
75	Hou X Y, Huang X Y, Li X Y, et al. A green aluminum-based metal organic framework outperforms its polymorph with MIL-53 type topology in o-xylene purification[J]. Separation and Purification Technology, 2023, 322: 124311.
76	Wang S Q, Mukherjee S, Patyk-Kaźmierczak E, et al. Highly selective, high-capacity separation of o-xylene from C₈ aromatics by a switching adsorbent layered material[J]. Angewandte Chemie International Edition, 2019, 58(20): 6630-6634.
77	Kumar N, Wang S Q, Mukherjee S, et al. Crystal engineering of a rectangular sql coordination network to enable xylenes selectivity over ethylbenzene[J]. Chemical Science, 2020, 11(26): 6889-6895.
78	Wang P, Kajiwara T, Otake K I, et al. Xylene recognition in flexible porous coordination polymer by guest-dependent structural transition[J]. ACS Applied Materials & Interfaces, 2021, 13(44): 52144-52151.
79	Sapianik A A, Dudko E R, Kovalenko K A, et al. Metal-organic frameworks for highly selective separation of xylene isomers and single-crystal X-ray study of aromatic guest-host inclusion compounds[J]. ACS Applied Materials & Interfaces, 2021, 13(12): 14768-14777.
80	Warren J E, Perkins C G, Jelfs K E, et al. Shape selectivity by guest-driven restructuring of a porous material[J]. Angewandte Chemie International Edition, 2014, 53(18): 4592-4596.
81	Ye Z M, Zhang X F, Liu D X, et al. A gating ultramicroporous metal-organic framework showing high adsorption selectivity, capacity and rate for xylene separation[J]. Science China Chemistry, 2022, 65(8): 1552-1558.
82	Lyndon R, Bacsa J, Jue M L, et al. Direct structural evidence of molecular packing effects of xylene isomers adsorbed in BIF-20[J]. Crystal Growth & Design, 2018, 18(5): 2890-2898.
83	Torres-Knoop A, Krishna R, Dubbeldam D. Separating xylene isomers by commensurate stacking of p-xylene within channels of MAF-X8[J]. Angewandte Chemie International Edition, 2014, 53(30): 7774-7778.
84	Vermoortele F, Maes M, Moghadam P Z, et al. p-Xylene-selective metal-organic frameworks: a case of topology-directed selectivity[J]. Journal of the American Chemical Society, 2011, 133(46): 18526-18529.
85	Holcroft J M, Hartlieb K J, Moghadam P Z, et al. Carbohydrate-mediated purification of petrochemicals[J]. Journal of the American Chemical Society, 2015, 137(17): 5706-5719.
86	Yoon J W, Lee J S, Piburn G W, et al. Highly selective adsorption of p-xylene over other C₈ aromatic hydrocarbons by Co-CUK-1: a combined experimental and theoretical assessment[J]. Dalton Transactions, 2017, 46(46): 16096-16101.
87	Saccoccia B, Bohnsack A M, Waggoner N W, et al. Separation of p-divinylbenzene by selective room-temperature adsorption inside Mg-CUK-1 prepared by aqueous microwave synthesis[J]. Angewandte Chemie International Edition, 2015, 54(18): 5394-5398.
88	Gao B, Tan L L, Song N, et al. A high-yield synthesis of [m]biphenyl-extended pillar[n]arenes for an efficient selective inclusion of toluene and m-xylene in the solid state[J]. Chemical Communications, 2016, 52(34): 5804-5807.
89	Jie K C, Liu M, Zhou Y J, et al. Near-ideal xylene selectivity in adaptive molecular pillar[n]arene crystals[J]. Journal of the American Chemical Society, 2018, 140(22): 6921-6930.
90	Dey A, Chand S, Ghosh M, et al. Molecular recognition and adsorptive separation of m-xylene by trianglimine crystals[J]. Chemical Communications, 2021, 57(72): 9124-9127.
91	He D L, Clowes R, Little M A, et al. Creating porosity in a trianglimine macrocycle by heterochiral pairing[J]. Chemical Communications, 2021, 57(50): 6141-6144.
92	Sun N, Wang S Q, Zou R Q, et al. Benchmark selectivity p-xylene separation by a non-porous molecular solid through liquid or vapor extraction[J]. Chemical Science, 2019, 10(38): 8850-8854.
93	Lusi M, Barbour L J. Solid-vapor sorption of xylenes: prioritized selectivity as a means of separating all three isomers using a single substrate[J]. Angewandte Chemie International Edition, 2012, 51(16): 3928-3931.
94	du Plessis M, Nikolayenko V I, Barbour L J. Record-setting selectivity for p-xylene by an intrinsically porous zero-dimensional metallocycle[J]. Journal of the American Chemical Society, 2020, 142(10): 4529-4533.
95	Pivovar A M, Holman K T, Ward M D. Shape-selective separation of molecular isomers with tunable hydrogen-bonded host frameworks[J]. Chemistry of Materials, 2001, 13(9): 3018-3031.
96	Ma L, Xie Y, Khoo R S H, et al. An adaptive hydrogen-bonded organic framework for the exclusive recognition of p-xylene[J]. Chemistry, 2022, 28(11): e202104269.

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