MODIFICATION OF REGENERATED CELLULOSE MEMBRANES FOR ORGANIC LIQUID PERMEATION AND THE USE OF SAID MEMBRANES TO RECOVER SELECTED ORGANIC LIQUIDS

摘要

ABSTRACT OF THE DISCLOSUREHydrophilic, semi-permeable , regenerated cellulose membranes areconverted to membranes useful for separating organic liquids by a processcomprising soaking the membranes in water to remove the glycol they normallycontain and then sequentially permeating the water-containing membranewith a series of solvents of decreasing polarity, under pressure, to dis-place the water in the membrane with the first solvent and then sequentiallydisplace each solvent in the membrane with the next, successive solvent ofdecreasing polarity, beginning with a low molecular weight alcohol or ketonewhich is completely miscible in water and ending with a solvent exhibitingbulk liguid-liquid miscibility with both the higher polarity solvent immediatelyproceeding it and the organic material desired to be selectively permeatedthrough the membrane and wherein there is complete bulk liquid-liquid misib-ility between any two adjacent solvents In the sequential series. Theseso-converted membranes are useful for selectively fractionating organicsolvent mixtures, (see apparatus figure 1), for selectively removing dewaxingsolvent from a dewaxed oil in solvent dewaxing processes (see process schemefigure 3) for removing aromatics from D naphtha stream, for recovering solventfrom slack wax/foots oils separation processes, (see process scheme figure 4)etc. The selective separation is accomplished by contacting the organic liquidsolution with one side of the modified regenerated membrane, under pressure,resulting in the selective permeation of one component through the membraneyielding n permeate richer in said selected component and a retentate leanerin said selected component.