Sulfur‐Limonene Polysulfide: A Material Synthesized Entirely from Industrial By‐Products and Its Use in Removing Toxic Metals from Water and Soil

Abstract

Apolysulfide material was synthesized by the direct reaction of sulfur and d-limonene,b y-products of the petroleum and citrus industries,r espectively.T he resulting material was processed into functional coatings or molded into solid devices for the removal of palladium and mercury salts from water and soil. The binding of mercury(II) to the sulfurlimonene polysulfide resulted in acolor change.These properties motivate application in next-generation environmental remediation and mercury sensing.The exploration of sustainable feedstocks is important in the synthesis of functional materials.[1] Herein, we report the utility of apolysulfide synthesized directly from two industrial by-products:s ulfur [2] and d-limonene [3] (Scheme 1). This study was inspired by classic reports on the reaction of sulfur and limonene, [4] theu se of limonene as ar enewable monomer, [5] and the recent and innovative applications of "inverse vulcanization" to access av ariety of advanced materials with high sulfur content. [6] We found that the sulfur-limonene polysulfide can be processed into coatings and solid devices that remove metal salts such as palladium-(II) and mercury(II) from water and soil. We also report the discovery of ac hromogenic response when the polysulfide is exposed to mercury(II). As sulfur is produced annually in excess of 60 million tons as ab y-product of petroleum refining [2] and more than 70 thousand tons of limonene are isolated each year from orange zest in the citrus industry, [3] the sulfur-limonene polysulfide is inexpensive-further motivating its use in metal sequestration, sensing,and environmental remediation.As as tarting point, sulfur was melted (T > 120 8 8C) and then heated to 170 8 8C. Above 150 8 8C, SÀSb ond scission occurs, [7] thereby generating thiyl radicals that could add to limonene.A ne qual mass of limonene was added to the molten sulfur,w hich produced at wo-phase mixture that becomes as ingle,d ark red phase upon reaction. An equal mass of sulfur and limonene was chosen to maximize the content of both industrial by-products in the final material. 1 HNMR analysis of the reaction mixture indicated limonenes exocyclic alkene was consumed more rapidly than its endocyclic alkene,w ith complete consumption of all olefins within 90 min (see Figures S6-S8 in the Supporting Information). Little change was observed by 1 HNMR spectroscopy on further heating. Scheme 1. Synthesis and applicationso fasulfur-limonene polysulfide.

The in situ synthesis of PbS nanocrystals from lead(II) n -octylxanthate within a 1,3-diisopropenylbenzene–bisphenol A dimethacrylate sulfur copolymer

“…Work by Pyun et al indicated that the reactor in which the ‘inverse vulcanization’ polymer was synthesized played an important role in the solubility of the 1,3-diisopropenylbenzne-sulfur polymers [ 57 ]. Other groups have published examples of ‘inverse vulcanization’ polymers with solubility in a wider range of organic solvents using different linkers including: divinylbenzene [ 67 ], allyl functionalized benzoxazine [ 68 ], S-farnesol [ 69 ] and S-limonene [ 60 ]. In this work, polymers ( 1 ) and ( 3 ) exhibited solubility in a wide range of organic solvents including: n -hexane, 1,2-dichlorobenzene, chloroform, toluene and dichloromethane.…”

Polymer Supported Carbon for Safe and Effective Remediation of PFAS-Contaminated Water

“…The blend is superior to GAC with respect to caking and rate of PFOA uptake. We also note that activated carbon 35 and the polymer 18,19,26,36 in this sorbent blend can, in principle, be made entirely from industrial waste and repurposed biomass-which merges our interests in using sustainable carbon 37,38 and sulfur polymers 18,19,23,25,26 for purifying wa-ter. The blend is scalable and we have prepared more than 25 kg in our laboratory.…”

“…The polymer is scalable and can be routinely prepared on a 1 kg scale in the laboratory. 19 These polysulfides and related polymers prepared by inverse vulcanisation 20 have been explored in a variety of applications including cathode materials for lithium-sulfur batteries, 20,21 lenses for infrared imaging, 22 heavy metal remediation, 18,[23][24][25][26][27][28][29][30] oil-spill clean-up, 19 and slow-release fertilisers. 31 The affinity of our canola oil polysulfide for hydrophobic materials like crude oil and other hydrocarbon pollution 19 prompted us to test its affinity for the perfluorinated backbone of PFAS.…”

Polymerizations with elemental sulfur: A novel route to high sulfur content polymers for sustainability, energy and defense

“…Since this manuscript was under review, a number of new studies on sulfur utilization for the synthesis and application of high sulfur content polymers have reported which point to the emerging potential of this field. [392][393][394][395][396][397][398][399][400][401][402][403][404][405][406][407]…”