NOVELTY - Separating methane (CH4) from a process feedstream, comprises: (a) contacting an adsorbent material comprised of a zeolitic imidazolate framework material with a process feedstream comprising CH4 and at least one C2+ hydrocarbon compound at a first pressure and first temperature; (b) adsorbing at least a portion of the C2+ hydrocarbon compound in the adsorbent material; (c) producing a CH4-rich product stream; and (d) producing a CH4-lean product stream at a second pressure and second temperature.    USE - The process is useful for separating CH4 from a process feedstream, which is comprised of: a natural gas; ethylene and CH4; propylene and CH4; or light plant gas feedstream (all claimed).    ADVANTAGE - The process is a swing adsorption process and the difference between the maximum and minimum C2+ hydrocarbon compound partial pressures achieved in the adsorbent bed during a cycle is less than 43.5 psia (300 kPa). The cycle time is less than 1 minute. The process requires less equipment size, cost and operating expenses at higher adsorptive loading ratios. The process can be operated at very low pressure. The process minimizes the compression required to raise the hydrocarbon feed stream to optimum separation conditions and completely eliminates compression equipment to raise the pressure of the feedstream.    DETAILED DESCRIPTION - Separating methane (CH4) from a process feedstream, comprises: (a) contacting an adsorbent material comprised of a zeolitic imidazolate framework material with a process feedstream comprising CH4 and at least one C2+ hydrocarbon compound at a first pressure and first temperature; (b) adsorbing at least a portion of the C2+ hydrocarbon compound in the adsorbent material; (c) producing a CH4-rich product stream, where the CH4-rich product stream has a higher concentration of CH4 by mol.% than the process feedstream; and (d) producing a CH4-lean product stream at a second pressure and second temperature, where the CH4-lean product stream has a lower concentration of CH4 by mol.% than the process feedstream, the zeolitic imidazolate framework material has a framework structure, each vertex of the framework structure is comprised of a single metal ion and each pair of connected adjacent vertices of the framework structure is linked by nitrogen atoms of an imidazolate anion or its derivative, and the zeolitic imidazolate framework material has an adsorptive loading ratio for the C2+ hydrocarbon compound over CH4 of at least 5.