LCA as a Tool to Detect Environmental “Hot Spots” in Early-Stage Mechanochemical Synthesis of Organic Dyes

Abstract

Mechanochemical methods are currently under investigation as alternative approaches to conventional solvent-batch synthetic chemistry. Environmental life cycle assessment (LCA) is needed to evaluate and compare chemical products made through mechanochemical processes with those from conventional production routes, using “cradle-to-gate” system boundaries. However, chemical supply chains involved in product manufacturing are often unknown, and synthesis tracing of these chemicals is needed to create life cycle environmental profiles. Herein, we trace the synthesis of the chemicals required to produce Pigment Black 31, a perylene diimide (PDI) organic dye, based on two main principles: maximum reaction yield and minimum synthetic steps. This approach facilitates comparing the environmental life cycle impact of producing Pigment Black 31 via twin-screw extrusion (TSE) with a conventional solvent-batch process, wherein similar reactants are used in both systems. The production of Pigment Black 31 via the TSE process affords a roughly order-of-magnitude reduction across global warming and human and ecological health life cycle environmental impacts following ReCiPe 2016 methods, mainly due to solvent reduction and elimination compared with production via the solvent-batch process. Interestingly, this reduction is found despite the need for a methanol extraction step in the purification of Pigment Black 31 made by TSE. We conclude that while LCA data sets may not be available for other organic dyes produced similarly through TSE processes, the life cycle environmental impacts for Pigment Black 31 can be used to approximate those of similar organic dyes, such as Pigment Black 32.

Towards sustainable synthesis: a life cycle assessment of polymer of intrinsic microporosity (PIM-1) by green mechanosynthesis

“…22 The evaluation of these metrics could potentially promote the development of green technologies in laboratories and industries. Moreover, there are also generic assessments such as Life Cycle Assessment (LCA) 23,24 or DOZN 2.0 (ref. 25) that are used extensively for the evaluations of environmental impacts of chemical processes.…”

Oxidative Leaching of Vanadium and Chromium from Vanadium Slag via a Mechanochemical Activation─Assisted Microbubbles Method

“…The enhancement in leachability through the MCA-assisted process stems from the creation of new surfaces, thereby instigating significant changes in chemical reactivity, material structure, and the release of excess energy. 16,19 In our previous work, the MCA process demonstrated a significantly superior leaching efficiency for V in the presence of Fe 2 O 3 , achieving 98.1%, compared to only 72.7% for the non-MCA treated slag. 20 While MB or MCA alone can facilitate V extraction from vanadium slag, the majority of Cr remains in the tailings.…”

“…The mechanochemical activation (MCA) hydrometallurgical process represents a recent cutting-edge technology for the efficient recovery of economically valuable metals from industrial solid waste and refractory ore. − This process significantly enhances leaching efficiency compared to non-activated samples. The enhancement in leachability through the MCA-assisted process stems from the creation of new surfaces, thereby instigating significant changes in chemical reactivity, material structure, and the release of excess energy. , In our previous work, the MCA process demonstrated a significantly superior leaching efficiency for V in the presence of Fe 2 O 3 , achieving 98.1%, compared to only 72.7% for the non-MCA treated slag . While MB or MCA alone can facilitate V extraction from vanadium slag, the majority of Cr remains in the tailings.…”

Environmental Impact Differences of Single-Chain Nanoparticle Production by Batch and Flow Chemistry

“…Table presents a summary of all scenarios for total energy input within the process (“gate-to-gate”) and solvent conditions in reaction and input where makeup solvent refers to the solvent supplemented to the reaction. Prior research has used scale-up procedures to develop material balance and energy input requirements for the LCI of chemical processes based on laboratory experiments and patent literature for pharmaceuticals and early stage chemical production processes. , …”