Time filter

Source Type

Toronto, Canada

Following our previous work on introducing a database of tested chemical examples from Organic Syntheses that can be used as a repository for problem set development in green chemistry courses, in this paper we extend this idea to include over 1300 examples taken from Inorganic Syntheses covering 36 volumes. Examples are sorted according to the following 13 categories: asymmetric syntheses, syntheses involving catalyst preparation, chemoenzymatic reactions, classical resolutions, convergent synthesis plans, kinetic resolutions; multicomponent reactions, multistep linear synthesis plans, natural feedstocks as starting materials, reactions involving product distributions, reactions involving sacrificial reagents, reactions involving nonunity stoichiometric coefficients, and polymerization reactions. In this paper, we highlight the skill of balancing chemical equations as a mandatory prerequisite of green metrics analysis. Through a problem set containing 70 exercises, we selected challenging examples from Inorganic Syntheses to emphasize this point and link it to the understanding of reaction mechanisms. A number of these examples also contain errors or missing information that students are asked to correct. This is yet another good training ground to exercise their skills in problem solving. © 2016 The American Chemical Society and Division of Chemical Education, Inc. Source

In this paper we present a standardized protocol for the complete evaluation of greenness of 18 industrial routes to methyl methacrylate (MMA) covering material and energy consumptions and environmental and safety impacts. A methodology for estimating energy consumption for chemical reactions and synthesis plans from published journal and patent literature procedures is fully described. A new energy metric pertaining to enthalpic changes from standard state conditions (298 K, 1 atm) to reaction conditions (Trxn, prxn) for all input materials used in a synthesis plan for the production of 1 mol of product is defined with respect to the heating and evaporation of 1 mol of water from 298 K and 1 atm. Limitations and best practices of running the protocol are discussed. The present study serves as a template for implementing the protocol to the green metrics analysis of high volume industrial chemicals. Results of plan rankings are compared with previous work on inherent safety indexes. Based on these findings, the isobutylene and t-butyl alcohol routes to MMA are found to have the overall greenest attributes among the 18 routes examined. © 2015 American Chemical Society. Source

After 20 years of green chemistry research, a complete algorithm for the determination of material and synthetic strategy efficiencies for synthesis plans to any chemical target has been achieved. This paper presents the first announcement of a comprehensive database consisting of green metrics calculations for 1060 plans to 220 targets of interest to the chemical industry in the following categories: commodity industrial chemicals, pharmaceuticals, agrichemicals, dyestuffs and colorants, natural products, flavorings, fragrances, and sweeteners, and molecules of theoretical interest. Data mining of the original literature covered the period 1828-2010. A summary of trends in achieving green chemistry strategies is presented, including an unbiased method of ranking plans using a suite of parameters, ring construction strategies, and implications on the development of new kinds of smart structure search databases. The take-home message is that targeted optimization is a multivariable problem that requires synergistic maximization and minimization of key variables. Problems in the reporting of chemical syntheses in scientific journals and patents are discussed as well as setting guidelines for their standardization and normalization. The merits of spreadsheet tools are presented from decision making in route selection all the way to fast and accurate proofreading of the final plan chosen. © 2011 IUPAC. Source

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. © 2012 American Chemical Society. Source

In this paper, we evaluate seven published algorithms on determining material efficiency green metrics for individual chemical reactions and synthesis plans with respect to their implementation by professional chemists and chemical engineers. Specifically, we compare and contrast calculation outputs, visual displays, and ease of use. For a direct head-to-head comparison of algorithm performances, thereby establishing consistency, all methods are tested on the same set of chemical examples taken from Organic Syntheses and journal articles that first introduced the algorithms in the literature. Misconceptions and misinterpretations of applying materials metrics analysis when making claims of greenness for reactions and synthesis plans are also discussed. © 2016 American Chemical Society. Source

Discover hidden collaborations