Direct Utilization of Elemental Sulfur in the Synthesis of Microporous Polymers for Natural Gas Sweetening

Abstract

Elemental sulfur, which is produced by a process called hydrodesulfurization mainly as a byproduct of the purification of natural gas, is one of the most abundant elements in the world. Herein, we describe solvent-and catalyst-free synthesis of ultramicroporous benzothiazole polymers (BTAPs) in the presence of elemental sulfur in quantitative yields. BTAPs were found to be highly porous and showed exceptional physiochemical stability. Moreover, in situ chemical impregnation of sulfur within the micropores increased CO 2 affinity of the sorbent while limiting diffusion of CH 4. As low-cost, scalable solid sorbents, BTAPs showed promising CO 2 separation ability and high regenerability under vacuum swing adsorption for the simulated flue gas, natural gas, and landfill gas conditions. The fact that elemental sulfur can be directly utilized in the synthesis of BTAPs means that it can be recycled back to the natural gas sweetening process for efficient CO 2 /CH 4 separation, thus offering a high-value, scalable, largescale application for elemental sulfur.

Perfluoroaryl‐Elemental Sulfur SNAr Chemistry in Covalent Triazine Frameworks with High Sulfur Contents for Lithium–Sulfur Batteries

“…The peak observed at 464 cm −1 was assigned to SS stretching band along with the CS stretching bands at 234 and 162 cm −1 . [2c] Moreover, the presence of D and G bands located at 1446 and 1535 cm −1 , respectively, indicates the graphitic nature of the CTF hosts. Notably, the intensities of the D and G bands were conspicuously lower for SF‐CTF‐1 (1:1) than for SF‐CTF‐1 (1:3) and SF‐CTF‐1 (1:5), once again because of the low‐degree of polymerization of SF‐CTF‐1 (1:1).…”

“…Sulfur is among the most abundant elements worldwide as it is mainly being produced as a by‐product from the purification of natural gas and oil. This involuntary production of sulfur leads to global supply surplus; thus, there is a growing interest in the scientific community for the direct utilization of elemental sulfur toward high value applications, and Li–S batteries are well‐aligned along such direction. There are, however, still significant challenges yet to be tackled in Li–S batteries; upon lithiation, sulfur transforms to soluble long‐chain lithium polysulfides (Li 2 S n , n = 4–8) in electrolytes, leading to severe capacity loss over cycling .…”

“…Chemical confinement of elemental sulfur, in principle, could address these issues. Polymer–sulfur composites can be obtained by the ring opening of elemental sulfur to a linear diradical form, which can undergo radical insertion reactions with various organic monomers and polymers bearing either unsaturated hydrocarbons[2b,12] or ArH and ArSH functionalities to form stable CS bonds. In this direction, Pyun and co‐workers demonstrated a direct copolymerization approach that involves the reaction of elemental sulfur with small aryl‐ethenyl or arylethynyl monomers via radical insertion mechanism at elevated temperatures.…”

High surface area sulfur-doped microporous carbons from inverse vulcanised polymers

“…22 The second route involved the reaction of aromatic methyl and amine-substituted monomers with elemental sulfur directly at elevated temperatures to make benzothiazole polymers. 23 Both of these routes gave materials with narrow pore size distributions, which can be benecial in gas separations, but also with relatively low Brunauer-Emmett-Teller surface areas (SA BET ): 537 m 2 g À1 (by nitrogen) as the highest for carbonised sulfur-DIB co-polymer, and 751 m 2 g À1 for the benzothiazole polymers (by argon). The organic precursors for the S-DIB and benzothiazole polymers are also considerably more expensive in comparison with sulfur.…”

Selective removal of cationic micro-pollutants using disulfide-linked network structures

“…2 Network polymers have been increasingly studied for their tunable functionalities, controllable pore geometries and wide range of applications. [35][36][37][38][39][40][41][42] Although conventional polymers and their derivatives, such as poly(acrylic acid), 43 cellulose, 44 carbonaceous materials, 45,46 poly(orthocarbonate), 47 microporous polymers, 48,49 poly(lactic acid), 50 polyaniline, [51][52][53] were used as superabsorbents to remove oils, metal ions, toxic dyes and organic solvents from water, some of these materials were synthesized by using transition metal catalysts and sometimes at high temperatures. 54 Therefore, new, low cost and effective adsorbents are always needed.…”