In this paper an adaptive controller–observer temperature control scheme is developed for a class of irreversible non-chain reactions taking place in batch reactors. The scheme is based on a nonlinear observer for the estimation of the heat released by the reaction, where the heat transfer coefficient is adaptively estimated. Tracking of the desired reactor temperature is achieved via a two-loop control scheme, where an independent adaptive estimate of the heat transfer coefficient is used as well. Remarkably, the observer and the controller can be designed and tuned separately. The convergence of both the nonlinear observer and of the overall controller–observer scheme is analyzed by resorting to a Lyapunov-like argument. A comparative simulation case study is developed to test the performance of the proposed scheme and compare it with other approaches already known in the literature