Abstract
This report describes the possibility of the repeated use of alkylhalide solvents, namely 1, 1, 2-trichloroethane and perchloroethylene at the time when carbonized intermediate product prior to activation (for simplicity, char) is produced from the sulfonation of propane-deasphalted asphalt (for simplicity, PDA) with oleum.
No influence of the repeated use of these solvents on the yield of char or activated carbon was recognized from the experimental results; they were very stable without damage or change in physical and chemical quality even after 20 times of repeated use along with oleum.
However, the ease of the sulfonation of PDA with oleum in solvent and the acti-vation of char with steam varied with the kind of solvents, so that 1, 1, 2-trichloroethane was adopted as a solvent for the sulfonation of PDA with oleum to obtain more suitable char for activation.
The recovery of solvent was always 98. 2'-98. 6wt.% because of distillation loss and the loss of solvent occluded in char. The concentration of acidic substances dissolving in recovered solvent was 1.0-1.5wt.% after first recovering, however, the accumulation of acidic substances was recognized only slightly after the repeated use of recovered solvents.
