Temperature control

Temperature is an important parameter to control when carrying out photochemical reactions. However, the use of high irradiance lamps during photochemical reactions, leads in most cases to a heating of the samples. That is why PhotoSpinner includes a fan (10 W) to force air into the reaction chamber. Moreover, this fan is coupled to a close-loop that allows to control the rotation of the fan, and consequently the temperature inside the reactor.

When a 4 mL acetonitrile sample is irradiated inside the photoreactor chamber with a Kessil PR160-456nm lamp, the sample heats up to 23°C above room temperature (black line). Controlling the power (P) supplied to the fan it is possible to control the reaction temperature of the sample. However, when the fan is running at 100% power, this temperature rise is only 5°C above room temperature (25ºC).

PhotoSpinner also includes the possibility of attaching a chiller to the fan. In this way, cooled air below ambient temperature is circulated inside the reaction chamber.

When a single Kessil PR160-456nm lamp is used in combination with fan and chiller, it is possible to carry on reactions at room temperature.

The amount of light received by the sample increases (learn more)[link a knowledge:Light Irradiation] when reactions when a second lamp is added. In that case, a sample consisting of 4 mL of acetonitrile is heated up to 45°C above room temperature when the fan is not connected. This difference is reduced to only 15°C when the fan is running at 100% power and to only 10°C when the chiller is used in combination with the fan. Alternatively, if ambient noise is not a problem for the user, a more powerful (20 W) but noisier fan, can be used to reach a temperature of 7ºC above room temperature without the need of a chiller, and 3ºC when the chiller is connected to the system.

Photospinner operating temperatures [ºC]*

Fan	No	10 W	20 W
Chiller	No	No Yes	No Yes
Single Lamp	23	6 0	4 0
Doble Lamp	45	15 10	7 3

*Temperature above room temperature (25ºC)

Temperature Control where it Matters

In its standard configuration, PhotoSpinner allows precise control and monitoring of the temperature inside the irradiation chamber, ensuring stable and reproducible experimental conditions.

In addition, the system can be equipped with a chemically resistant thermocouple that can be mounted directly into one of the reaction vessels, enabling real-time monitoring of the temperature within the reaction itself rather than in the surrounding chamber.

This capability provides direct access to the true reaction temperature, improving experimental control, comparability, and reproducibility.