Micro- and Ultramicroporous Polyaminals for Highly Efficient Adsorption/Separation of C₁–C₃ Hydrocarbons and CO₂ in Natural Gas

Abstract

This paper presents a series of micro- and ultramicroporous polyaminals with BET surface areas up to 1304 m2 g–1, which are prepared from two triazine-based tetraamines and three dialdehydes or monoaldehyde through the A4 + B2 or A4 + B1 aminalization reaction. It is interesting to find that the para-substituted monomers are favorable to force the linking struts apart in the network to generate micropores (1.22 nm), whereas the meta-substituted monomers make the pores in the network squeezed by the twisted linking struts, resulting in the formation of ultramicropores (0.52 nm). Besides, the adsorption behaviors of the major components of natural gas, such as propane (C3H8), ethane (C2H6), methane (CH4), and carbon dioxide (CO2), are significantly different, strongly depending on the polarizabilities, critical temperatures, molecular sizes of gases, porosity parameters of polymers, and the interaction between gases and the polymer skeleton. At 298 K/1 bar, the polymers show high uptake for C3H8 (114.5 cm3 g–1) and C2H6 (84.2 cm3 g–1). Moreover, the adsorption selectivities of C3H8/CH4, C2H6/CH4, C3H8/C2H6, C3H8/CO2, C2H6/CO2, and CO2/CH4 also reach 296.3, 23.1, 9.0, 22.1, 4.1, and 5.0, respectively, exhibiting promising applications in adsorption/separation of C1–C3 hydrocarbons and stripping CO2 gas from natural gas under the ambient condition.

Porphyrin-Based Nanoporous Organic Polymers for Adsorption of Carbon Dioxide, Ethane, and Methane

“…As seen in Table , the C 2 H 6 uptake value of 80.2 mg/g obtained by PNOP-1 at a temperature of 273 K far surpasses those of previously reported porous organic polymers under equivalent environmental conditions, such as 49.6–61.3 mg/g for sPI, 32.3–67.2 mg/g for aromatic MPI polymers, and <80 mg/g for mesoporous hydrophobic polymeric organic frameworks (mesoPOFs) . Finally, the PNOPs obtained CH 4 uptake values in the range of 14.6–16.8 mg/g at 273 K and 1 bar, which are comparable with those obtained by previously reported porous organic polymers such as BILP-5 (15 mg/g), ALP-4 (14.3 mg/g), and PAN-m1 (17.1 mg/g) . The results in Table also demonstrate that the CO 2 , C 2 H 6 , and CH 4 adsorption capacities of PNOP-1 are distinctly higher than those of PNOP-2, PNOP-1 shows high nitrogen content and microporous surface areas as well as microporous volume compared with PNOP-2.…”

“…49 Finally, the PNOPs obtained CH 4 uptake values in the range of 14.6−16.8 mg/g at 273 K and 1 bar, which are comparable with those obtained by previously reported porous organic polymers such as BILP-5 (15 mg/g), 50 ALP-4 (14.3 mg/g), 2 and PAN-m1 (17.1 mg/g). 4 The results in Table 2 also demonstrate that the CO 2 , C 2 H 6 , and CH 4 adsorption capacities of PNOP-1 are distinctly higher than those of PNOP-2, PNOP-1 shows high nitrogen content and microporous surface areas as well as microporous volume compared with PNOP-2. The observed CO 2 , C 2 H 6 , and CH 4 adsorption properties of the PNOPs were evaluated further by applying the Clausius− Clapeyron equation to calculate the isosteric enthalpies of adsorption (Q st ) from the CO 2 , C 2 H 6 , and CH 4 adsorption isotherms measured at 273 and 298 K. The results are plotted in Figure 6 as functions of the CO 2 , C 2 H 6 , and CH 4 adsorption capacities of the PNOPs obtained at various pressures in Figure 4.…”

“…This has led to the development of new types of nanoporous organic polymers with high nanoporosity, excellent physicochemical stability, and low energy adsorption for the adsorption and separation of CO 2 , as well as for other applications, such as the adsorption and separation of other simple molecular gases (e.g., C 2 H 6 , CH 4 , N 2 , etc. ), , catalysis, − drug delivery, , sensors for toxic pesticide detection, , and water treatment. , Owing to extensive application as well as excellent physicochemical properties, the design and construction of nanoporous organic polymers for simple molecular CO 2 adsorption/separation has become a hot research area in science and industry.…”

High-Throughput Computational Screening of Metal–Organic Frameworks for the Separation of Methane from Ethane and Propane

“…In a recent study, Li and Wang investigated a series of microporous and ultramicroporous polyaminal networks (PANs) for the separation of C 1 −C 3 hydrocarbons in natural gas. 47 These PANs have the Brunauer−Emmett−Teller SA in the range of 904−1133 m 2 /g and pore volume in the range of 0.62−0.87 cm 3 /g. At ambient conditions, they reported selectivity of propane over methane in a 10:90 (propane/methane) mixture in the range 129.3−296.3 and selectivity of ethane over methane in a 10:90 (ethane/methane) mixture in the range 16.9−23.1.…”

Facile synthesis of highly porous hyper‐cross‐linked polymer for light hydrocarbon separation

“…For petrochemical industry, light hydrocarbon separation is essential, and offers a variety of necessities related to our life. [1][2][3] Currently, the Traditional purification method of distillation is often employed to separate light hydrocarbons under low-temperature and highpressure conditions. [4][5][6] However, this purification process is generally associated with huge energy consumption, which accelerates the process of depleting global energy resources and exacerbates environmental pollution problems.…”