Cellulose derivatives containing adamantane groups are homogeneously synthesized by a simple, rapid and environmentally friendly way using 1-allyl-3-methylimidazolium chloride (AmimCI) ionic liquid as reaction media. Without any catalysts, cellulose adamantates (CAd) with degree of substitution (DS) in a range horn 0.71 to 2.25 are prepared just in one-step. In addition, a series of mixed esters, cellulose adamantate acetate (CAdAc), are also synthesized via the "one-pot" process. The obtained CAd and CAdAc are characterized by means of FT-IR, NMR, XRD, DSC and TGA. Meanwhile, their gas pet meabilities of these materials for O-2, N-2, CH4, CO and CO2 are studied. CAd exhibits improved solubility in organic solvents, low glass transition temperature and good thermostability. In particular, the free-volume topology of CAd membranes has been tailored by controlling the DS of adamantane, thus CAd membranes display a significant enhancement for gas permeability with good ideal permselectivity for several gas pairs, such as O-2/N-2, CO2/N-2, CO2/CH4 and CO2/CO. For CAdAc, introducing only a small amount of adamantane groups in cellulose acetate could achieve better gas permeability and similar or slightly lower ideal permselectivity. (C) 2014 Elsevier B.V. All rights reserved,