Design method of extractant for liquid–liquid extraction based on elements and chemical bonds

Abstract

In the petrochemical industry process, the relative volatility between the components to be separated is close to 1 or the azeotrope that systems are difficult to separate. Liquid–liquid extraction is a common and effective separation method, and selecting an extraction agent is the key to extraction technology research. In this paper, a design method of extractants based on elements and chemical bonds was proposed. A knowledge-based molecular design method was adopted to pre-select elements and chemical bond groups. The molecules were automatically synthesized according to specific combination rules to avoid the problem of "combination explosion" of molecules. The target properties of the extractant were set, and the extractant meeting the requirements was selected by predicting the correlation physical properties of the generated molecules. Based on the separation performance of the extractant in liquid–liquid extraction and the relative importance of each index, the fuzzy comprehensive evaluation membership function was established, the analytic hierarchy process determined the weight ratio of each index, and the consistency test results were passed. The results of case study based on quantum chemical analysis demonstrated that effective determination of extractants for the analysis of benzene–cyclohexane systems. The results unanimously prove that the method has important theoretical significance and application value.