ISOMER COMPOSITIONS OF TRIMETHYLBENZENE OR TRICHLOROBENZENE IN ALPHA-CYCLODEXTRIN PRECIPITATES FORMED IN AN AQUEOUS-MEDIUM

Upon introducing the vapor of binary mixtures of trimethylbenzene (TMB ) or trichlorobenzene (TCB) isomers into an alpha-cyclodextrin (alpha- CyD) aqueous solution, and circulating it in a closed system, CyD was precipitated with the isomers. In (1,3,5-1,2,3 or 1,2,4,)-TMB systems of various mixing ratios, the mole fraction of 1,3,5-TMB in the total TMBs precipitated was considerably lower than that of 1,2,3- or 1,2,4- TMB: selective precipitation of 1,2,3- or 1,2,4-TMB occurred in the pr esence of 1,3,5-TMB. The concentration of alpha-CyD in the supernatant aqueous solution was determined as a function of the isomer mixing ra tio. The selectivity was rather poor in the cases of TCB systems. Tern ary mixtures of TMB isomers were also studied to a less extent. The so lubility product constants at 25 degrees C were proposed for TMB and T CB precipitates with alpha-CyD.