Fractional extraction with hollow fibers with hydrogel‐filled walls

Extractions using hollow fibers can be faster and more efficient than those in conventional equipment. These advantages, due to the large area per volume possible with fibers, can be compromised by accidental convection through the fibers' pores. When these pores are filled with gels of crosslinked polyvinyl alcohol, convection through the pores is stopped but the overall mass transfer is unaltered. The separations across these gel‐filled fiber walls provide excellent yield and purity, especially in the case of fractional extraction.