The effect of modifiers in scCO2 on the demetallization of vacuum residue is established.
Methanol and o-xylene provide the highest concentration of metals in the extract.
Ethyl acetate, n-heptane and toluene show a low selectivity towards metals.
Increasing the toluene concentration in CO2 sharply increases extract yield.
Toluene as modifier provides high demetallization efficiency at high extract yields.