PDF Publication Title:
Text from PDF Page: 004
ACS Sustainable Chemistry & Engineering Perspective Table 2. Twelve Principles of Green Chemistry 1. Waste prevention not remediation 2. Atom efficiency 3. Less hazardous/toxic materials 4. Safer products by design 5. Innocuous solvents and auxiliaries 6. Energy efficient by design Scheme 2. High Atom Economy Processes 7. Renewable rather than depleting raw material 8. Shorter synthesis (avoid derivatization) 9. Catalytic rather than stoichiometric reagents 10. Design products for degradation 11. Analytical methods for pollution prevention 12. Inherently safer processes 2) by Anastas and Warner in 1998,11 in which the overall guiding element is “benign by design”. ■ CATALYSIS: THE SOLUTION TO POLLUTION As the phloroglucinol example clearly showed, a major source of waste, particularly in the fine chemicals and pharmaceuticals industries, is the use of stoichiometric reagents in organic synthesis. Illustrative examples are stoichiometric oxidations with chromium(VI) reagents, permanganate and manganese dioxide, and reductions with metal hydride reagents (LiAlH4, NaBH4) and metals (Na, Mg, Zn, Fe). Similarly, mineral acids (H2SO4, HF, H3PO4) and Lewis acids (AlCl3, ZnCl2, BF3), employed as reagents in a wide variety of reactions such as Friedel−Crafts alkylations and acylations, and bases, used in stoichiometric quantities in many classical organic syntheses, are major sources of waste. The solution to waste minimization in (fine) chemicals manufacture is evident: substitution of archaic stoichiometric methodologies with atom economic catalytic alternatives.12,13 After all, a catalyst is a substance that accelerates the rate of a chemical reaction without being consumed and, therefore, not generating waste. Relevant examples of high atom economy processes are catalytic hydrogenation, oxidation, carbonylation, and hydroformylation (Scheme 2). Solvent losses are another major source of waste in industrial organic synthesis, and in our original inventorization of the E factors of industrial processes if solvent losses were not known, we assumed that they would be 10% of the amount used in the process. In hindsight, this was probably overly optimistic, certainly in the case of multistep syntheses of advanced pharmaceutical intermediate (APIs), where different solvents are often used for the various steps and cross-contamination becomes an issue. It is also worth mentioning that solvents are not always needed or can be used in much lower amounts, for C example, in slurry to slurry processes. In short, the key to green and sustainable chemistry is the use of catalysisheteroge- neous, homogeneous, organocatalysis and biocatalysisin organic synthesis.14 Since the solution is so obvious, why have catalytic processes not been as widely used in pharmaceuticals and fine chemicals manufacture as in bulk chemicals? One reason is that much smaller production volumes are involved, and therefore, the need to minimize waste was less acute than in bulk chemicals manufacture. A second reason is that the economics of bulk chemicals manufacture dictate the use of the least expensive reagents which, generally speaking, were the most atom economical. For example, O2 and H2O2 are not only the least expensive oxidants (per mole), they also have the highest atom economy in oxidation processes. Similarly, H2 and CO are highly atom economical reagents for reduction and C−C bond formation, respectively. Additional reasons are the fact that time-honored classical stoichiometric reagents generally exhibit broad applicability and shorter development times compared with that of cleaner, catalytic alternatives. Consequently, environmentally (and economically) inferior technologies are often used to meet stringent market deadlines, and subsequent process changes are prohibitive owing to problems associated with regulatory approval. Nonetheless, driven by the pressing need to reduce waste, in the last two decades, more emphasis has been placed on the use of catalytic methods in organic synthesis, in particular, in the manufacture of advanced pharmaceutical intermediates (APIs).15 ■ Atom Economy and the E Factor. In order to perform meaningful comparisons of different routes to a particular product, we need metrics to measure greenness.16−20 The two oldest green metrics, the above-mentioned atom economy DOI: 10.1021/acssuschemeng.7b03505 ACS Sustainable Chem. Eng. XXXX, XXX, XXX−XXX MASS-BASED METRICS OF GREENNESSPDF Image | Metrics of Green Chemistry and Sustainability
PDF Search Title:
Metrics of Green Chemistry and SustainabilityOriginal File Name Searched:
acssuschemeng.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)