Thermodynamic and molecular mechanisms of ionic liquids for acetylene dehydration

Abstract The production of acetylene (C 2 H 2 ) via calcium carbide method is an industrial process commonly used in the production of polyvinyl chloride resin. The dehydration of C 2 H 2 is one crucial aspect. In this work, a novel approach based on ionic liquid (IL) separation was explored. Thermodynamic properties of the IL were predicted using the COSMO‐SAC model to screen for an appropriate absorbent. The loss of C 2 H 2 and dehydration performance of IL during dehydration were measured by solubility experiment and laboratory‐scale absorption experiment. Quantum chemistry (QC) calculations and molecular dynamics (MD) simulations were utilized to explore the mechanism of the C 2 H 2 dehydration process. [EMIM][Tf 2 N] was selected as the final absorbent to achieve highly selective dehydration with low C 2 H 2 losses. Anions play a leading role in the dehydration process, and the dehydration effect mainly depends on hydrogen bonds. This work provides guidance for the rational design of a new absorbent for C 2 H 2 .