In the laboratory, how to accurately control the reaction temperature of the laboratory glass reactor?

To maintain an accurate thermal environment inside a laboratory glass reactor, four complementary strategies are routinely combined. First, the laboratory glass reactor should be connected to a programmable circulating thermostatic bath whose PID parameters have been pre-tuned for the vessel volume and solvent heat capacity. This external loop continuously pumps silicone oil or a low-viscosity heat-transfer fluid through the jacket of the laboratory glass reactor, allowing ramp-and-soak profiles that can reproduce a set-point within ±0.1 °C. Second, a high-precision Pt100 sensor is inserted directly into the reaction mixture rather than placed in the jacket inlet; this eliminates the lag between the actual batch temperature and the controller reading, a critical issue when scaling from 100 mL to 5 L laboratory glass reactor systems. Third, moderate magnetic or mechanical stirring (200–600 rpm) prevents thermal stratification, ensuring that every layer inside the laboratory glass reactor experiences the same temperature. Finally, for exothermic or sub-ambient reactions, a cascade control algorithm is implemented: the bath outlet temperature is dynamically offset by the rate of heat evolution measured via calorimetric sensors, so the laboratory glass reactor never overshoots during sudden exotherms. By integrating these four elements—calibrated bath, in-situ probe, homogeneous agitation, and predictive algorithms—chemists can hold the temperature of a laboratory glass reactor within ±0.05 °C even when the set-point is changed from −20 °C to 180 °C across a 12-hour run.