Inclusion of Environmental Impact Parameters in Radial Pentagon Material Efficiency Metrics Analysis: Using Benign Indices as a Step Towards a Complete Assessment of “Greenness” for Chemical Reactions and Synthesis Plans

Abstract

A new benign index (BI) parameter is developed and applied to assess the overall "greenness" of chemical reactions and synthesis plans. Previously described radial pentagon green metrics based solely on material efficiency are extended to include BI which takes into account the following potentials for environmental harm: acidification−basification (ABP), ozone depletion (ODP), global warming (GWP), smog formation (SFP), inhalation toxicity (INHTP), ingestion toxicity (INGTP), inhalation carcinogenicity (INHCP), ingestion carcinogenicity (INGCP), bioconcentration (BCP), abiotic resource depletion (ARDP), cancer potency (CPP), persistence (PER), and endocrine disruption (EDP). As with other material efficiency metrics, the benign index is defined as a fraction between 0 and 1 so that it may be added as another radial axis to produce an overall radial hexagon diagram that can be used to evaluate the "green" merits of any given chemical reaction. The utility of the method is demonstrated for industrial chemical reactions producing diphenyl carbonate (DPC) and phenyl isocyanate (PI) using both phosgene-based and nonphosgene-based chemistries, and for synthesis plans for the industrial production of aniline, phenol, and aspirin. A critical discussion is presented on the limitations of the method with respect to proper decision making in route selection, particularly the availability and reliability of key parameters, and the importance of obtaining experimental data for key parameters rather than relying solely on computational methods.

Waste-Minimized Cyanosilylation of Carbonyls Using Fluoride on Polymeric Ionic Tags in Batch and under Continuous Flow Conditions

“…At this stage, we have also studied the different parameters to have a deeper comprehension of the environmental features of the process, by considering the BI 81 and the SHI 82 for the input materials (Table 5) and all the green metrics (E-factor, PMI, AE, and RME). We also compared in detail other protocols reported in the literature (Table 6).…”

A comparative approach to the most sustainable protocol for the β-azidation of α,β-unsaturated ketones and acids

“…In carrying out a detailed green metrics analysis three groups of metrics were examined: (a) material efficiency metrics (reaction yield, AE, 3 global RME, 5 E-factor, 1c-e PMI); 6 (b) environmental impact metrics (see the Appendix for a list of potentials and the benign impact index for waste materials 39 ); and (c) safety-hazard metrics (see the Appendix for a list of potentials and the safety-hazard impact index for waste materials 40 and for input materials 40 ). To ensure fairness in ranking, a set of reactions chosen for comparison leading to a particular product had a common starting substrate.…”

How Efficient Is My (Medicinal) Chemistry?

“…Values collected in Table 1 and Table 3 can readily be inserted in radial polygons [ 17 , 32 , 33 ] in which each summit would represent a value of 100% and the center a value of 0%; note that 100/SF rather than SF is used in those representations. Although pentagons are often preferred for that purpose, we chose the hexagon by assigning one summit to the EcoScale value (excluding the penalty points for safety).…”