Carrier Facilitated Transport of Urea using Synthetic Noncyclic Receptors through Supported and Bulk Liquid Membrane Systems

Molecular recognition and transport phenomena are important in host guest and biomimetic system. Urea has a long history in host-guest chemistry, is primarily concerned with the non-covalent interaction involved hydrogen bonding between receptors and urea.

A series of synthetic non-cyclic receptors diethylene glycol (R₁), triethylene glycol (R₂), tetraethylene glycol (R₃), acetoacetate diester of diethylene glycol (R₄), acetoacetate diester of triethylene glycol (R₅) and acetoacetate diester of tetrathylene glycol (R₆) have been synthesized and used as a carrier for transport of urea through bulk (chloroform) and supported (egg shell, PTFE and dialysis) membrane systems.

The sequence of urea transported by using different receptors is R₆ > R₅ > R₄ > R₃ > R₂ > R₁. It is found that the receptor R₆ shows maximum transport of urea with eggshell membrane. Effects of various parameters such as concentration of urea and receptors, nature of membrane supports have been studied. Investigate the best membrane and altering the structure of receptors can be correlated to quantitative structure property relationship (QSPR) which helps in fabrication of urea sensors.