EFFECT OF PHOSPHORUS-COMPOUNDS ON THE ACTIVITY OF CATALYST (ZN(II), CO(II), MN(II) IN THE POLYCONDENSATION OF BIS(2-HYDROXYETHYL) TEREPHTHALATE

As the first step to clarify the role of phosphorus compounds in the catalytic polycondensation of bis(2-hydroxyethyl) terephthalate, effect of phosphorus compounds on the activity of catalyst (Zn(II), Co(II), Mn(II)) was studied. When phosphoric acid was used, the polycondensation rate decreased linearly with increasing its molar ratio to the catalyst and the reaction practically did not proceed on addition of phosphoric acid of molar equivalent to the catalyst or more. The unfavorable effect of phenylphosphorus compounds decreased in the following order; (HO)3PO>C6H5(HO)2PO>(C6H5)2(HO)PO>(C6H5)3PO, the effect of triphenylphosphine oxide being negligible. By the addition of a trialkyl phosphate the activity of catalyst also decreased depending upon its alcohol component in the following order; (HO)3PO>(CH3O)3PO>(C2H5O)3PO>(n-C4H9O)3PO. It was made clear that this inhibitory effect of trialkyl phosphates is due to the complexation of the catalyst with phosphoric acid which was formed in situ in the early stage of the polycondensation. © 1979, The Society of Polymer Science, Japan. All rights reserved.