The disclosed technology relates to a process for conducting a chemical reaction between at least one liquid reactant and at least one gaseous reactant in a process microchannel containing at least one catalyst, the catalyst comprising a solid phase catalyst or a homogeneous catalyst immobilized on a solid. In one embodiment, the process microchannel comprises a processing zone containing one or more structures for disrupting fluid flow and a reaction zone containing one or more structures for contacting and/or supporting the catalyst, the one or more structures for contacting and/or supporting the catalyst containing openings to permit the reactants to flow through the one or more structures and contact the catalyst. The process comprises: forming a reactant mixture comprising at least one liquid reactant and the at least one gaseous reactant; flowing the reactant mixture in the processing zone in contact with the one or more structures for disrupting fluid flow to enhance mixing of the liquid reactant and the gaseous reactant; flowing the reactant mixture in openings in the one or more structures for contacting and/or supporting the catalyst in contact with catalyst; and reacting the at least one liquid reactant with the at least one gaseous reactant to form at least one product. In one embodiment, the process relates to a process for conducting a Fischer-Tropsch synthesis in a process microchannel containing at least one Fischer-Tropsch synthesis catalyst, the catalyst comprising a solid phase catalyst or a homogeneous catalyst immobilized on a solid, the process comprising: flowing reactants comprising H 2 and CO in the process microchannel, the inlet superficial velocity of the reactants being at least about 0.1 m/s; contacting the Fischer-Tropsch synthesis catalyst with the reactants; and reacting the reactants in the presence of the catalyst to form at least one product.