Eco‐Balance Assessment of Ionic Liquids as Acid Catalysts in Transesterifications

Abstract

Eco-Balance Assessment of Ionic Liquids as Acid Catalysts in TransesterificationsIonic Liquids may act as homogeneous catalysts for transesterification processes. In contrast to conventional catalysts the ionic liquid may be separated after reaction and recycled. This study investigated the ecological effect of changing from sulfuric acid as catalyst to an ionic liquid. Three different eco-balance approaches have been applied. The EHS method proved to be the most suited tool to assess the ecological potential of process alternatives in the conceptual process design phase. Keywords

Continuous Transesterification with Acidic Ionic Liquids as Homogeneous Catalysts

“…This behavior is disadvantageous in an integrated reaction and product separation scheme as it requires additional separation effort and acid make-up in the reactor. Based on these results, IL-catalyzed transesterification with catalyst recycle was recently assessed versus conventional H 2 SO 4 catalysis employing different ecobalance approaches [9].…”

“…Based on the experiments conducted and reported here, at least a 100-fold recycle of the IL catalyst can be expected. Further optimization of reaction and recycling conditions should allow for up to 500 recycles, resulting in an economically and ecologically competitive process [9]. …”

“…Additionally, the IL-catalyzed transesterificaton process has the potential to be ecologically advantageous compared to the reaction with sulfuric acid as catalyst [9]. In addition, ILs have been shown to be versatile entrainer substances for the separation of narrow-boiling or azeotropic mixtures [10].…”

Continuous dehydration of Ionic Liquids in a falling film evaporator

“…When used as process fluid in extraction, absorption or extractive distillation processes, separation, purification and recycling is mandatory to achieve economic as well as ecological competitiveness. Based on economical and ecological considerations a minimum number of recycles may be quantified which is necessary to achieve respective benefits for the use of IL [3]. The necessity of multiple recycles requires effective and gentle separation techniques in order to maintain solvent and process qualities.…”