Fluorinated porous organic frameworks for C2F6/CF4 gases separation

Abstract

As an indispensable raw material for silicon-based semiconductor industry, carbon tetrafluoride (CF4) is widely used as plasma etching and cleaning gas in the manufacture of semiconductors. How to efficiently remove the C2F6 impurity during the CF4 production process is a challenging task as semiconductor industry requires high-purity CF4 gas. Herein, two fluorine-functionalized porous organic frameworks (F-POFs) named SPPOF-4F and SPPOF-8F were synthesized and used for separation of C2F6/CF4 gases. Single-component gas adsorption experiments and ideal adsorbed solution theory (IAST) calculations indicate that two porous organic frameworks can selectively adsorb C2F6 from C2F6/CF4 mixture. Molecular simulations have further complemented these experimental findings by revealing F-induced host-guest interactions between F-POFs and C2F6 at a molecular level. Additionally, dynamic breakthrough experiments verified that the F-POFs can capture C2F6 in C2F6/CF4 mixture at practical conditions. These results indicate that F-POFs have great potential for application in the separation and purification of CF4 electronic special gases.