A Green Nucleophilic Aromatic Substitution Reaction

This laboratory activity focuses on the tie-dyeing process as a safer alternative to nucleophilic aromatic substitution (SNAr) reactions for an introductory organic chemistry laboratory. The simple and straightforward experiment provides students with an opportunity to gain practical experience in conducting a chemical reaction in a real-world context while applying concepts of design for biodegradability and reusability. The water-soluble reactive dye that replaces the use of a conventional SNAr substrate does not require any heavy metals, toxic substances, or mordants but utilizes a much less toxic and safer sodium carbonate to generate the cellulosate nucleophile. This reaction generates no waste, and the end-product, the tie-dyed T-shirt, is reusable and biodegradable. Through this experiment, students can see connections between chemistry and environmental health while gaining a practical insight into dyeing chemistry, making use of a systems thinking approach. This experiment serves not only to employ safer alternatives to hazardous chemicals in the undergraduate organic chemistry laboratory but also to educate students to recognize the relevance and importance of applying green chemistry wherever it is possible, emphasizing life cycle thinking and environmental stewardship.

A Green Nucleophilic Aromatic Substitution Reaction. L. Abraham. J. Chem. Educ. 2020, 97, 10, 3810-3815.
DOI: 10.1021/acs.jchemed.0c00181