NOVELTY - A compact chemical reactor (10) has first (12) and second (14) unit reactors disposed adjacent each other to form front side (32) and back side (34) of the reactor; front reactant plenum (36) communicating with the front side; and back reactant plenum (38) communicating with the back side.    USE - Used as compact chemical reactor.    ADVANTAGE - The invention provides for a small compact chemical reactor capable of low cost manufacturing with fewer parts than the layered planar structure chemical reactor, capable of being scaled to micro-dimensions, to reduce leakage and manufacturing costs, and with high aspect ratio cavities.    DETAILED DESCRIPTION - The compact chemical reactor with a central axis comprises first and second unit reactors disposed adjacent each other to form front side and back side of the compact chemical reactor; front reactant plenum communicating with the front side; and back reactant plenum communicating with the back side, the reactant plenums comprising a reactant. Each unit reactors comprises a front process layer; a back process layer; a front cavity formed between the front and back process layers; a back cavity formed between the back process layers and the front process layer of adjacent unit reactors; a front perimeter barrier disposed on the back process layer substantially surrounding the back cavity; and a back perimeter barrier disposed on the front process layer substantially surrounding the front cavity and the front cavity is in communication with the front side and the back cavity is in communication with the back side and the process layer facilitates a transport process between the reactant plenums. The unit reactor comprises frame formed from the process layers, perimeter barriers, and cavities. The cavity is in communication with a side of the compact chemical reactor, and process layer facilitates a transport process between the reactant plenums.    DESCRIPTION OF DRAWING(S) - The figure is a perspective view of a flat construction of the chemical reactor with frames.    Compact reactor (10)    First reactor unit (12)    Second reactor unit (14)    Unit reactors (16-31)    Front side (32)    Back side (34)    Front reactant plenum (36)    Back reactant plenum (38)    Structure (40)    Device (42)    Solid back wall (43)