Complexing Organic Carboxylic Acid Extraction And Its Qsar Study

Carboxylic acids are important chemical industrial material and intermediate product. Reactive extraction, the equilibrium constant of which, is important thermodynamic property, is a kind of important separation method to thin solution of carboxylic acids.In the present paper, the structure of studied compounds molecule were described by Electrotopological State Indices for atom type(ETSI). The structure and solubility of 658 organic compounds cited from literatures were related and their models were established by Multiple Linear Regress(MLR). The results showed that ETSI descriptors were sufficient for differentiating the structure of 658 studied compounds; the model based on MLR had 14 ETSI descriptors as its independent variables, and its modeling estimate relative coefficient(r) and Leave-One- Out cross validation relative coefficient(q) were 0.9074 and 0.9019. Estimating accuracy was satisfying.Glycolic acid was extracted with tri-octylamine(TOA) as extraction reagent and chloroform, n-octanol, toluene, xylene as diluent. Formic, acetic, propyl, butyl, lactic, crylic, malonic, succinic, malic, tartaric, maleic, salicylic and p-nitryl benzyl acid were extracted with n-octanol as diluent. Factors affecting the extraction resut had been discussed. Models based on supposed reaction mechanism were built; reactive extraction equilibrium constant K₁₁, K₁₂ were got by linear or non-linear regression of experiment data. The results showed that supposed reaction mechanism fit experiment data well and the model was also able to predict experiment data well.Meanwhile, the quantitative relationship between carboxylic acids reaction extraction equilibrium constant and their structures(QSAR) was studied. The model built by MLR had 6 ETSI descriptor as its independent variables, and its modeling estimate relative coefficient(r) and Leave-One- Out cross validation relative coefficient(q) were 0.9987,0.9721.