Comparisons between Green Matrix and Green Star analyzes of caffeine extraction and purification techniques as a way of reflecting on the greenness of chemical processes studied in higher education

Abstract

Green Chemistry allows to think about chemical processes to minimize physical, health and environmental risks and reduce reagent and resource costs. With the holistic metrics Green Star and Green Matrix, it is possible to evaluate experiments chemical greenness degree, as well as strengths and weaknesses, in relation to the principles of Green Chemistry. Given the complementarity between the metrics, this paper aims to compare the analysis of two caffeine extraction processes and two caffeine purification techniques by both. It was possible to evidence protocols steps that confer risk or high energy consumption, indicating points of attention, except for the purification by sublimation, which presents high chemical verdure. Also, it was possible to understand that the two metrics differ in detail level and, while Green Star facilitates the graphical visualization of the principle’s compliance, Green Matrix allows to present improvements in the processes. Finally, it was possible that the analyses agreed on the experiments chemical greening rates, indicating complementarity.