NOVELTY - Water-gas shift reaction in a single stage process channel (20), involves flowing reactants (10) comprising carbon monoxide and water through the process channel that contains a water-gas shift reaction catalyst and flowing coolant fluid through a coolant channel in thermal contact with the process channel, resulting in formation of a first reaction zone and a second reaction zone in the channel.    USE - Used for effecting a water-gas shift reaction in a single stage process channel to form a product comprising H2 and CO2. The H2 from the product is used to operate a fuel cell, used to hydrogenate, hydrotreat, hydroalkylate, hydrocrack or hydrodesulfurize a feedstock, reacted to form hydrogen chloride, hydrogen bromide, ethanol, methanol or ammonia, used to make a metal hydride, used to hydrogenate a fat or an oil, used to reduce a metal ore or used to reduce a catalyst (all claimed). The process is useful for conducting acetylation addition reactions, alkylation, dealkylation, hydrodealkylation, reductive alkylation, amination, ammonia synthesis, aromatization, arylation, autothermal reforming, carbonylation, decarbonylation, reductive carbonylation, carboxylation, reductive carboxylation, reductive coupling, condensation, cracking, hydrocracking, cyclization, cyclooligomerization, dehalogenation, dimerization, epoxidation, esterification, Fischer-Tropsch reaction, halogenation, hydrohalogenation, homologation, hydration, dehydration, hydrogenation, dehydrogenation, hydrocarboxylation, hydroformylation, hydrogenolysis, hydrometallation, hydrosilation, hydrolysis, hydrotreating, isomerization, methylation, demethylation, metathesis, methanol synthesis, nitration, oxidation, partial oxidation, polymerization, reduction, reformation, reverse water gas shift, sulfonation, telomerization, transesterification, trimerization, Sabatier reaction, carbon dioxide reforming, preferential oxidation or preferential methanation.    ADVANTAGE - The process inhibits undesired reactions to carbon dioxide. It has a higher overall conversion with lower overall methane selectivity.    DETAILED DESCRIPTION - Water-gas shift reaction in a single stage process channel, comprises:    (A) flowing reactants comprising carbon monoxide (CO) and water (H2O) through the single stage process channel that contains a water-gas shift reaction catalyst (30), where the reactants contact the catalyst as they flow through the process channel and undergo an exothermic reaction resulting in the formation of the product (40) comprising hydrogen (H2) and carbon dioxide (CO2), and    (B) flowing a coolant fluid (50) through a coolant channel in thermal contact with the process channel, resulting in the formation of a first reaction zone and a second reaction zone within the process channel, where the first reaction zone is near the entrance to the process channel and the second reaction zone is near the exit to the process channel. The temperature within the first reaction zone is higher than the temperature within the second reaction zone. The rate of formation of the product is greater in the first reaction zone than in the second reaction zone, and the conversion of CO increases as reactants flow through the second reaction zone.    DESCRIPTION OF DRAWING(S) - The figure shows a water-gas shift reaction in a single stage process channel.    Reactants (10)    Process channel (20)    Catalyst (30)    Product (40)    Coolant fluid (50)