Sulfates of Sorghum vinegar residue waste as potential catalysts

Abstract

A sealed wet curing design on sulfating Sorghum vinegar residue waste is drilled with sulfo/sulfoalkyl chemicals. Sulfation degrees in the case of reactions with sulfuric acid, sodium sulfite, sulfamic acid, benzenesulfonic acid, p-toluenesulfonic acid and sodium laurilsulfate range from 14.7 to 36.9 mg sulfo per gram waste. The C–O–S formation gives rise to accessional noncrystallinity and mesoporosity of morphology, a character for potential alternatives in catalysis. Waste sulfates are employed as candidates in catalyzing the condensation of α-glycolic acid and urea substitutes for yielding imidazolidine-2,4-dione derivatives. Catalytic and specific activities in terms of derivative productions are 2.6–34.3 (×103 U) and 0.8–5.4 U/mg sulfo, together with the maximal yields of 49.4%–97.6%. Chemical linkage of sulfo/sulfoalkyl groups manifests synergism with intrinsic acidity of waste with respect to catalysis. A rational design of green chemistry is guaranteed by no excess of chemicals and easy recyclability of catalysts.

Keywords

• agroindustrial waste reutilization
• heterogeneous catalyst
• imidazolidine-2,4-dione derivatives
• sorghum vinegar residue (svr)
• sulfation modification