A novel method to separate molecular mixtures to very high purity has been developed by IISc researchers led by S Yashonath in the Solid State and Structural Chemistry Unit.

Existing methods separate the components of a mixture by driving them to move at different speeds along the same direction in a column of porous solid such as zeolite. They usually lead to an impurity of 1 molecule in 100. The new method causes the molecules to move to opposite ends of the column, resulting in better than 1 in 10¹⁰ separation.

The method judiciously combines two well-studied phenomena: levitation effect and blow torch effect. The researchers used it to separate a mixture of a linear hydrocarbon called n-pentane and its branched isomer, neopentane, to very high purity. Such separations are routinely carried out in petroleum refineries, but consume large amounts of energy. This new method is more energy-efficient by several orders of magnitude. It will also be useful in green chemistry where high purity reactants are required.