PDF Publication Title:
Text from PDF Page: 012
idants of questionable safety (158). Polycarbonate waste can be converted into starting materials for polyurethane; in a one-pot procedure, the waste polymer is converted into bisalkoxylated diols of Bisphenol A, which is then polymerized with urea (159). Production of biofuels generates large quantities ofglycerol(about1kgforevery10kgofbiofuel); finding valuable applications has been a challenge. Using a green chlorodehydroxylation technique (160), a Belgian company has built a facility to produce epichlorohydrin from glycerol and hydrochloric acid instead of propylene and chlorine (161). Glycerol can also be converted into propylene glycol by reactive distillation and hydrogenation, providing an alterna- tive to the traditional route based on propylene oxide (162) (Figure 13). Archer Daniel Midlands Co. has announced plans to build a large scale glycerol-to- propylene oxide manufacturing facility (163). The company IUCT in Barcelona, Spain uses glycerol from biodiesel production as a starting material for new solvents and fuels. The use of CO2 as a renewable source of carbon has been recently reviewed (164). While use of CO2 as a raw material is not expected to mitigate the ‘‘green- house gas’’ effects of CO2 in the atmosphere, the non- toxic, non-flammable gas is considered to be an environmentally friendly reagent. Currently, the most industrially promising uses of CO2 as a feedstock are in the formation of carbonate small molecules and polymers. Dimethyl carbonate, as discussed earlier, is a green alternative to phosgene in polycarbonate and polyurethane synthesis. Ironically, dimethyl carbon- ate is conventionally synthesized from phosgene. New methods for dimethyl carbonate synthesis have been devised, for example a one-pot conversion based on a cyclic carbonate, using methanol and a heterogeneous Mg-based catalyst (165) (Figure 14). Cyclic carbo- nates, useful intermediates for polycarbonate synth- esis, can now be prepared directly from alkenes instead of preformed epoxides, avoiding extra syn- thetic steps. The synthesis from alkenes has additional green characteristics: it is performed in water without use of metal catalysts (166). The development of highly active polymerization catalysts operating under mild conditions has been key in preparing polycarbo- nates from CO2 and epoxide compounds (167). The Figure 13. Reactive distillation of glycerol over copper- chromite catalyst yields propylene oxide. The process is carried out at relatively low temperature and pressure, producing less byproduct than previous systems (162). resulting polymers have variable plastic properties but poly(cyclohexene carbonate) shows promise as an alternative to polystyrene. A CO2 sequestration and utilization process known as Supramics captures waste CO2 from flue gas and incorporates it into cement-fiber composites. The process has low energy requirements, and the product replaces building materials that result in emission of CO2 and other waste byproducts (168). The path forward As we consider the past accomplishments outlined in the preceding sections, it is useful to try and identify conceptual perspectives of green chemistry that will help take the field to the next level of maturity. While the advances above have been of the highest quality science, many of the advances have been made well within a single sub-discipline within chemistry. Other advances, while rigorous and useful, have been incremental steps forward in making our chemical design more sustainable and environmentally benign. A large portion of our resources of time, funding, and intellectual dedication to the subject of sustainability has been devoted to convincing policy makers, consumers, and members of the scientific community of the magnitude of the problems confronting the world that are due to our historical and present-day unsustainable products, processes, and systems. Green chemistry needs to continue to be a driving force in addressing these serious issues by identifying the future possibilities. These possibilities will not happen small step by small step. We simply do not have the luxury of time. Dramatic transformative advances will need to be part of the portfolio of future green chemistry technologies in order to get us where we need to be within the timeframe required. 1. The Twelve Principles of Green Chemistry need to be understood not as a collection of individual isolated goals but rather as a design framework. Design is the conscious statement of human inten- tion. While it may be possible to make products and processes less hazardous or more efficient as a by- product of research endeavors, green chemistry is a framework for the design of products and processes such that the goals themselves, e.g. degradability or less toxic products, are essential performance cri- teria. It will not be enough to simply consider these goals as ‘‘added features’’ that are ancillary to the central purpose of the molecules, materials and transformations. It will be important that these goals are intrinsic design specifications. In that way, it will be obvious that when a hazardous and unsustainable product or process is produced, there are only two explanations: (1) there is a design flaw or (2) it was designed to be hazardous. Green chemistry: the emergence of a transformative framework 19PDF Image | Green chemistry: the emergence of a transformative framework
PDF Search Title:
Green chemistry: the emergence of a transformative frameworkOriginal File Name Searched:
green-chemistry.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)