Microwave‐Assisted Kolbe‐Schmitt Synthesis Using Ionic Liquids or Dimcarb as Reactive Solvents

Abstract

Abstract The activation of relatively inert carbon dioxide as a building block for organic products is of interest from both ecological and chemical points of view. One of the few industrially relevant processes using CO 2 is the Kolbe‐Schmitt synthesis. Two strategies to obtain the carboxylated product 2,4‐dihydroxybenzoic acid from resorcinol are presented: both Dimcarb and hydrogencarbonate‐ or methylcarbonate‐based ionic liquids are employed as reactive solvents in a microwave‐assisted reaction. Reaction optimization shows that the ionic liquids are more reactive than Dimcarb. However, Dimcarb offers advantages with regard to ecological aspects, such as the Global Warming and Human Toxicity Potential and the Cumulative Energy Demand, which were assessed as part of the process development.