Economic Sulfur Conversion to Functional Polythioamides through Catalyst-Free Multicomponent Polymerizations of...

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Chemistry

Background:

• Sulfur utilization is a global challenge due to environmental concerns.
• Sulfur-containing polymers offer valuable properties like metal coordination and semiconducting behavior.
• Synthesizing polymers directly from elemental sulfur is difficult.

Purpose of the Study:

• To develop a catalyst-free and scalable method for synthesizing sulfur-containing polymers.
• To create diverse polythioamides with high molecular weights and yields.
• To explore the application of these polymers in gold recovery from electronic waste.

Main Methods:

• Multicomponent polymerizations (MCPs) using elemental sulfur, dicarboxylic acids, and diamines.
• Synthesis of 12 distinct polythioamides with varied structures.
• Application of synthesized polythioamides for selective gold (Au3+) extraction.

Main Results:

• Achieved high yields (up to 99%) and molecular weights (up to 86,200 g/mol) in polythioamide synthesis.
• Successfully utilized both aliphatic and aromatic diamines, yielding rigid structures.
• Demonstrated efficient gold recovery (>99.99%) from electronic waste leachate with high capacity (0.60 g/g).

Conclusions:

• Catalyst-free MCPs provide a facile route to diverse, high-performance polythioamides from elemental sulfur.
• These polythioamides show significant potential for recovering precious metals from waste streams.
• The method supports sustainable resource utilization by repurposing sulfur waste and gold residue.