A mass transfer system of H2C2O4-H2O/HDEHP (bis(2-ethylhexyl) phosphate)-TBP(tributyl phosphate)-Cu-CCl4 was established, which resulted in the production of copper oxalate precipitation. In an improved Lewis mass transfer cell, the mass transfer process between inorganic phase composed of oxalic acid water solution and the organic phase composed of HDEHP-TBP-Cu-CCl4 were researched by shifting solvents, extraction agents, the ratio of HDEHP and TBP, stirring rate, extraction time, etc. Precipitation produced by mass transfer process was characterized by IR, XRD, TG, TEM and SEM. The mass transfer reaction and system factors, which influence the size and shape of the products, were analyzed. Based on the mass transfer rate, kinetics parameters of the reaction and precipitation response of oxalic acid, HDHEP and TBP in the H2O-H2C2O4/HDEHP-TBP-Cu-CCl4 system, the theory of inter-phase dispersion zone (IDZ) in liquid-liquid system were further developed and the evolution law of dynamic microemulsion was uncovered. (C) 2014 Elsevier B.V. All rights reserved.