the invention relates to a process for the performance of chemical reactions , more particularly for the production of plastics by means of extruders . the conveying path in the extruder is subdivided into different temperature zones whose temperature can be adjusted independently of one another . as a result , numerous chemical reactions can be performed in a controlled and continuous manner . the invention also relates to an apparatus for the performance of the process , the corresponding extruders having separately temperable casing compartments and being equipped with independent tempering devices . application to chemical reactors for light to medium production runs .