NOVELTY - Conversion of alkane involves providing a flow (F1), providing a catalytic flow-through reactor configured to accept the flow (F1), catalytically converting at least a portion of the alkane in presence of hydrocarbon conversion catalyst to produce a reaction mixture, quenching the reaction mixture in the flow-through reactor by transferring heat from the reaction mixture to the thermal mass at a location downstream of the hydroconversion catalyst, in which the downstream is based on flow (F1)'s flow direction, and cooling the thermal mass after quenching.    USE - Conversion of alkane used for forming olefins.    ADVANTAGE - The method enables simple and efficient conversion of alkane with high selectivity.    DETAILED DESCRIPTION - Conversion of alkane involves providing a flow (F1), providing a catalytic flow-through reactor configured to accept the flow (F1), catalytically converting at least a portion of the alkane in the presence of the hydrocarbon conversion catalyst to produce a reaction mixture, quenching the reaction mixture in the flow-through reactor by transferring heat from the reaction mixture to the thermal mass at a location downstream of the hydroconversion catalyst, in which the downstream being with respect to the flow (F1)'s flow direction, and cooling the thermal mass after the quenching. The flow (F1) comprises alkane and oxidant in molar ratio of 2 or more. The catalytic flow-through reactor comprises at least one hydrocarbon conversion catalyst and at least one thermal mass, in which the hydrocarbon conversion catalyst has an initial average temperature of 550-1100 degrees C, at least a portion of the thermal mass is located downstream of the hydroconversion catalyst with respect to the flow's (F1) flow direction, and a portion (P1) of the thermal mass has an initial average temperature such that the difference of hydroconversion catalyst's initial average temperature and portion (P1) of the thermal mass's initial average temperature is 50 degrees C or more. The catalytic conversion includes catalytically-transferring hydrogen from the alkane to the oxidant and the reaction mixture comprises an olefin produced by the catalytic transfer and unreacted alkane and/or unreacted oxidant. INDEPENDENT CLAIMS are included for the following:    (1) reverse-flow reactor, which comprises thermal masses (M1) and (M2), regions (R2), (R3), (R4) and (R5), one or more reaction zone (1) located in the region (R2), one or more sorbent zone (Z'1) in the region (R1), and one or more sorbent zone (Z'2) in the regions (R3) and (R4). The thermal mass (M1) includes one or more passages adapted for fluid flow. The region (R1) and region (R2) are adjacent, non-overlapping regions. The regions (R3) and (R4) are adjacent, non-overlapping regions. The region (R1) contains the portion (P1) of the thermal mass (M1) and the region (R2) contains the portion (P2) of the thermal mass (M1). The region (R3) contains the portion (P1) of the thermal mass (M2) and the region (R4) contains the portion (P2) of the thermal mass (M2). The region (R5) is a non-overlapping region located between the regions (R2) and (R3), and is adapted for fluid communication between the thermal masses (M1) and (M2) and optionally for fluid mixing process. The reaction zones contain hydrocarbon conversion catalyst. The catalyst comprises one or more hydrogen transfer catalyst and/or at least one oxy-dehydrogenation catalyst. The hydrocarbon conversion catalyst is in fluid communication with the passages of the thermal mass (M1). The sorbent zone (Z'1) contains one or more olefin-selective sorbent which is in fluid communication with the passages of the thermal mass (M1). The reaction zones contains at least one oxy-dehydrogenation catalyst which is in fluid communication with the passages of the thermal mass (M2). The sorbent zone (Z'2) comprises at least one olefin-selective sorbent that is in fluid communication with the thermal mass (M2); and    (2) flow-through reactor, which comprises reactor vessel configured for fluid-flow, one or more hydrocarbon conversion catalyst located within the reactor vessel, in which the hydrocarbon conversion catalyst is contacted with the fluid-flow and includes one or more oxidative coupling catalyst and/or one or more oxy-dehydrogenation catalyst, one or more sorbent located in the reactor vessel, in which the sorbent is selective for olefin sorption and contacted with the fluid-flow, and one or more thermal mass located in the reactor vessel, in which the thermal mass is contacted with the fluid-flow, and a portion of mass is located between the hydrocarbon conversion catalyst and the sorbent.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of two stage reverse-flow reactor.    Reaction zone (1)    Reactor stages (102,104)    Sparger (108A)    Conduits (110,112,114,116,118,120)    Distributor (122A)