Adsorption limitation investigation on olefins for Cu-BTC

Abstract To utilize Cu-benzene-1,3,5-tricarboxylate (Cu-BTC) adsorbed lubricant oils in the self-lubricating field, the adsorption properties of Cu-BTC on different 1-olefins must be clarified. In this work, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene were studied by the Monte Carlo method and experimentally. The adsorption limit of Cu-BTC for n-olefins was determined as 1-undecene by the adsorption isotherms. This suggested a limit for even straight-chain molecules to the adsorption of Cu-BTC. The maximum ratio of the olefin length of the largest pore diameter (L/D) of Cu-BTC was approximately 1.57. Furthermore, theoretical calculations (radial distribution function (RDF)) and experiments (infrared (IR) spectra) confirmed the interaction of n-olefin adsorbates and the Cu-BTC framework occurred between the -CH= of olefins and the Cu and O atoms of the Cu-BTC framework. This work adds to the understanding and investigation of the adsorption of liquid lubricants using Cu-BTC as a metal-organic framework (MOF).