In this study, a high-pressure membrane reactor (MR) was employed to carry out the methanol synthesis (MeS) reaction. Syngas was fed into the MR shell side where a commercial MeS catalyst was used, while the tube side was swept with a high boiling point liquid with good solubility toward methanol. A mesoporous alumina ceramic membrane was utilized after its surface had been modified to be rendered more hydrophobic. The efficiency of the MR was investigated under a variety of experimental conditions (different pressures, temperatures, sweep liquid flow rates, and types of sweep liquids). The results reveal improved per single-pass carbon conversions when compared to the conventional packed-bed reactor. An ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate, was utilized in the MR as the sweep liquid. The experimental results are compared to those previously reported by our group (Li, Z.; Tsotsis, T. T. J. Membrane Sci. 2019, 570, 103) while using a conventional petroleum-derived solvent as sweep liquid, tetraethylene glycol dimethyl ether (TGDE). Enhanced carbon conversion (over the petroleum-derived solvent) was obtained using the IL.