CONTINUOUS PROCESS FOR PREPARING POLY(BUTYLENE TEREPHTHALATE) OLIGOMER OR POLY(BUTYLENE ISOPHTHALATE) OLIGOMER

摘要

Economic and efficient process for preparingan oligomer of poly(butylene terephthalate) or anoligomer of poly(butylene isophthalate) from atransesterification reaction mass by using acountercurrent column reactor system wherein thetransesterification reaction mass is fed into thecountercurrent column reactor and continuously flowsdownward while simultaneously a heated inert gasstream continuously flows upward to scrub outvolatiles from the transesterification reaction mass,thereby yielding from the bottom of the countercurrentcolumn reactor an oligomer of poly(butyleneterephthalate) or an oligomer of poly(butylene.isophthalate) suitable for use in a polycondensationreaction. Butanediol is recycled throughout theprocess through an absorber column.