TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The step of sparging comprises forcing the fluid reactant across a permeable wall configured to sparge the fluid reactant, where the permeable wall comprises a catalyst material. The method further comprises: the step of removing the liquid before the step of sparging and recycling at least a portion of the liquid into the helical constrained flow; preheating the fluid reactant via heat exchange with a collected liquid, the collected liquid is the liquid after sparging with the fluid reactant; and helically mixing the fluid product after sparging, where the helically mixing comprises alternating clockwise and counter-clockwise helical rotation. Preferred Components: The reactor further comprises: a plenum chamber (26) oriented between the sparging fluid inlet and the constrained-flow unit to allow distribution of the sparging fluid into the sparging portion; a cooling mantle thermally associated with the reactor body and configured for removing heat from the liquid during exothermic reaction; a separation unit fluidly connected between the helical flow path and the liquid outlet and gas outlet, the separation unit allowing at least partial separation of gases and liquids; a gas preheater operatively coupled to provide sparging fluid to the sparging fluid inlet and thermally associated with the separation unit, where the sparging fluid is heated by heat transferred from the separation unit before introduction into the sparging fluid inlet; and a demister fluidly connected to the gas outlet. The gas outlet is fluidly connected to the axial interior volume such that gases can be withdrawn up through the axial interior volume. The helical constrained flow unit further comprises a helical mixing section oriented downstream of the sparging portion. The helical constrained flow is substantially enclosed helical flow path. The sparging portion is at least one of a porous mass or a perforated wall.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The liquid: is an ionic liquid; and further comprises a particulate solid catalyst material to form catalyst slurry. The liquid comprises: a liquid reactant; and an oil carrier. The fluid reactant comprises many fluid reactants, preferably synthesis gas. The fluid product is methanol, dimethyl ether (preferred), Fischer-Tropsch reaction products, higher alcohols, oxidation products, oligomerization products, hydrogenation products or hydrotreated hydrocarbons. EXAMPLE - Sample of catalytic slurry containing bifunctional catalyst (comprising cuprous oxide, zinc oxide and aluminum oxide methanol synthesis catalyst (95 wt.%) and zeolite (H-ZSM-5) methanol dehydration catalyst (5 wt.%)) (20 wt.%) in the form of fine particles was suspended in an inert paraffin oil, and Penreco (RTM: Petroleum hydrocarbon), was introduced to the slurry container. The reactor system was purged with nitrogen flow through gas preheater and nitrogen flow was replaced with the flow of catalyst pre-reduction mixture (comprising hydrogen (4%) and nitrogen (96%)). The reaction was carried out at 260 degrees C at 0.5 degrees C/minute and kept at peak temperature for 8 hours. After pre-treatment, the hydrogen-nitrogen mixture flow was replaced with the flow of dimethyl ether reaction feed syngas (hydrogen/carbon monoxide = 1) and the reactor was pressurized to 50 bar. The reaction was maintained at 260-265 degrees C. Then dimethyl ether and methanol vapors were separated from unreacted syngas and directed to the liquid product tank to give dimethyl ether.