Improved Method for Separation of Organic Isomers

Researchers in Oxford University’s Department of Inorganic Chemistry have devised a novel method for separating polar organic compounds, providing a useful alternative to the usual methods of chromatography or crystallisation.

The separation of mixtures of organic and inorganic compounds is of considerable importance in most areas of industrial and academic chemistry. In particular, isomeric mixtures are often difficult to separate and can require highly specialised techniques.

Conventional separation techniques involving chromatography or absorption are capable of removing impurities from process streams. Isomeric mixtures can be separated by crystallisation and other methods, but this is usually difficult due to the similar physical properties of the isomers. Any improvement in the efficiency or selectivity of a separation process can lead to increased product purity and significant cost savings.

The new Oxford technique provides a straightforward and novel method for separating polar organic compounds, and is a useful alternative to the usual methods of chromatography or crystallisation. Layered materials have been used for the intercalation of organic and inorganic species, principally with reference to specific clays. Specifically, layered double hydroxides have been used for the separation of 1,2- and 1,3- and 1,4-benzenedicarboxylic acids in greater than 95% selectivity. Research has continued, and in excess of 99% separation of 1,5-naphthalene sulphonate over the 2,6- isomer has been observed. Similar separations have been achieved for benzenedisulphonate. Differences in the intercalation rates between the mono- and di- substituted isomers have enabled a selectivity series to be devised. Work is ongoing to further evaluate this useful technique for isomer separation.

Isis Innovation, Oxford University’s technology transfer company, has filed a patent application for this technology and welcomes contact from companies interested in commercial exploitation.