Copolymers of methyl acrylate and acrylic acid were synthesized to fabricate membranes ionically crosslinked using aluminum acetylacetonate for the separation of toluene/i-octane mixtures by pervaporation at high temperatures. The formation of the ionic crosslinking via bare aluminum cations was characterized by UV-VIS spectroscopy and solubility tests. Reproducibility and the reliability of the methodology for membrane formation and crosslinking were confirmed. The effects of acrylic acid content, crosslinking conditions, pervaporation temperature, and feed composition on the normalized flux and the selectivity for toluene/i-octane mixtures were determined. A typical crosslinked membrane showed a normalized flux of 26 kg mum m(-2) h(-1) and a selectivity of 13 for a 50/50 wt.% feed mixture at 100 degreesC. The pervaporation properties including solubility selectivity and diffusivity selectivity are discussed in terms of swelling behavior. The performance of the current membranes were benchmarked against other membrane materials reported in the literature.