Pages 428–430
Abstract
Research summary supplied by the authors
The leather industry generates large quantities of fleshing waste rich in proteins and lipids, which pose significant environmental challenges when disposed of untreated. This study focuses on the valorization of animal fleshing waste through the synthesis of highvalue waxe esters suitable for leather finishing applications. Fat was first recovered from fleshing waste using a hydrothermal extraction process at 120 °C and 15 psi, yielding oil with ~23.8% fat content. The extracted triglyceride-rich oil was subjected to de-esterification in alkaline tetrahydrofuran to obtain free fatty acids. NMR and mass spectrometric analysis confirmed oleic acid as the predominant constituent. Subsequently, waxes were synthesized via esterification of the isolated fatty acids with long-chain alcohols such as dodecanol and octadecanol in the presence of a sulphamic acid catalyst. The synthesized waxes displayed appropriate melting characteristics which could make them a suitable replacement for the burnish wax. Additionally, by careful selection of the chain length of the alcohol, the waxes with variable melting points could be synthesized, making this route a versatile method for the synthesis of wax emulsions. For application studies, the waxes were emulsified using SDS and IPA to form stable dispersions and were applied to leather substrates via spray coating. The treated leathers exhibited desirable surface aesthetics, improved polishability, and burnishability, demonstrating performance comparable to commercial waxes. This work establishes a sustainable route to convert tannery solid waste into value-added finishing materials, supporting circular economy initiatives in leather manufacturing.