How to take the removal of condensation water into account in polyesterification kinetics?

In previous polyesterification reactions, the concentrations of reactants a nd catalyst (if present) were all expressed in moles per kilogram. In most cases, the progress of reaction was followed by the titration of acid group s. Consequently, the removal of condensation water is bound to affect the c oncentrations of reactants and catalyst. In this paper, a new general kinet ic equation has been derived, which takes this effect due to the removal of condensation water into consideration more accurately. The unit of mol l(- 1), who replaced the unit of mol kg(-1), is led into the calculation of aci d concentration and the derivation of the general polyesterification kineti c equation for the first time. Its adoption can finally eliminate the error due to the change of the density of reaction system while adopting the uni t of mol kg(-1).