Catalytic membrane reactors (CMRs) are predictable to develop a green and maintainable skill in chemical engineering which synergistically conducts separations and reacts. The use of a ceramic membrane is commonly known in CMR as it enables all temperature and chemical reaction and separation to be carried out in severe environments. Within this segment, a detailed description and review of various applications adopt specific definitions and principles for membrane reactor operation. Such programs are classified according to the items addressed. The essay explores and assesses from the present viewpoint the ability of the different definitions. Because production rates are precise diverse and in general at actual poor technology readiness levels (TRL), they have not joined a list with admiration for price effectiveness, operation quality, and applicability. To facilitate more oriented research and growth, however, it is important to demonstrate a single or limited number of membrane reactors on a market-applicable size and expense. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.