A method for alkyl oxygenate (e.g., methanol) manufacture via partial oxidation of alkane (methane) uses an injectively-mixed backmixing reaction chamber in fluid communication with a tubular-flow reactor. Alkyl free radicals are induced in the backmixing reaction chamber prior to being fed through a flow-restriction baffle to the tubular-flow reactor. Injective intermixing of feed streams agitates the backmixing reaction chamber. In one embodiment, a variable position flow restriction baffle is axially moved to commensurately modify the backmixing reaction chamber and tubular-flow reactor volumes. In another embodiment, the tubular-flow reactor is quenched with a variable position quenching input. The method further provides for condensing the output stream from the reaction system in a condensing scrubber and also for recycling a portion of the scrubbed output stream to the reactor system.