Adsorption of chloro:fluorocarbon(s) onto hydrophobic molecular sieve - composed of dealuminised natural or synthetic zeolite with a well defined pore size

摘要

A process for the adsorption of halogenated hydrocarbons (I), opt. contg. other heteroatoms, pref. N and/or O and/or S is claimed. (I) are adsorbed from a gaseous or liq. form, onto inorganic, non-combustible, hydrophobic molecular sieves (II) whose pore dia. is equal or greater than the critical mol. dia. of (I) and is then opt. recovered from the pores. Pref. (II) has a high thermal stability and good acid resistance, with a pore dia. of 0.4-1.5mm and is a natural or synthetic zeolite, pref. dealuminised with a Si/Al ratio of greater than 10 or is a microporous silica cpd.. Aluminium phosphate or silicon aluminium phosphate is added and the adsorption carried out, without utilising temp. or pressure effects after a pressure swing adsorption process. (II) is brought into contact with the process gas or medium in a fluidised bed. (I) is recovered by simple desorption, pref. by temp. and/or pressure swing desorption. (I) is partially or perhalogenated and is pref. chlorinated and/or fluorinated with a halogen/hydrogen ratio of at least 1:1 for partially halogenated and is greater than 3:1, pref. 5:1 for more highly halogenated cpds.. The process is carried out on a mixt. of perhalo-, partially halogenated and non-halogenated hydrocarbons. USE/ADVANTAGE - Useful for the removal of chlorofluorocarbons from the environment. The absorbent is non-combustible and is hydrophobic with a well defined pore size and is safer and more selective than prior art processes.