Activated Carbon Sheets from Pomegranate Peel with Ionic Liquid for Knoevenagel Condensation: Synthesis of Aryledene and Xanthene Derivatives

SUBHASH BANERJEE^1*Dhaneshwar Prasad¹Archana Asatkar²Swetalana Prerna Ram³Shripal Singh³Santosh Kumar Prajapati¹Swetlana Prerna Ram³

• ¹Guru Ghasidas Vishwavidyalaya, Bilaspur, India
• ²Government Nagarjuna Post Graduate College of Science, Raipur, India
• ³CSIR-CIMFR Regional Research Centre Bilaspur, Bilaspur, India

Pomegranate peel–derived activated carbon (PPAC) nanosheets with lateral dimensions of 40–200 nm and lengths of 4–10 μm were synthesized through a sustainable carbonization followed by a KOH activation strategy. Comprehensive characterization using Raman spectroscopy, powder XRD, FESEM, FESEM-EDX, and TGA confirmed the formation of two-dimensional graphitic carbon sheets with high surface activity. The PPAC, in combination with the ionic liquid [pmIm]Br, exhibited remarkable catalytic performance in the Knoevenagel condensation of aromatic aldehydes with active methylene compounds, affording the corresponding aryledene derivatives in excellent yields (90–95%) within 5–20 min under mild conditions. Beyond this, the PPAC/[pmIm]Br catalytic system efficiently promoted the synthesis of xanthene derivatives via a tandem condensation–cyclization pathway. The catalyst was readily recovered and reused over five consecutive cycles with minimal loss of activity. This work establishes a renewable biomass-derived carbon framework as a dual-function, eco-compatible catalyst for efficient C–C bond formation and heterocycle construction, providing a scalable route aligned with green chemistry and waste valorization principles.