Organic synthesis in the pharmaceutical industry very often involves compounds having molecular weights between 300 to 1000. Such organic synthesis usually consists of multiple reaction steps. There is considrable need for athermal concentration or separation of the larger molecular weight product from the solvent and lower molecular weight species laft in the reaction mass. Solvent-compatible nanofiltration (NF) membranes are likely to be of considerable use in such applications. In addition, for equilibrium-limted reactions, the extent of reaction can be considerably influenced by coupling NF with an organic synthesis reaction. Experimental results of the NF separation behavior of three different organic solutes of molecular weights 351, 826 and 1355 at two different feed concentrations are illustrated for three different NF membranes. These NF membranes are organics stable and have manufacturer-reported molecular weight cut offs of 250 400 and 700, respectively. The solvent used was methanol; the pressure applied was 440 psig (3.04 MPa). The solvent flux and solute rejection behavior will be presented as a function of time.
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