1,720,978 research outputs found
GREEN METRICS: COMPARATIVE ASSESSMENT OF AN ALTERNATIVE SYNTHESIS OF 5-BENZYL-3-FURFURYL ALCOHOL, A KEY INTERMEDIATE FOR THE PRODUCTION OF RESMETHRINS
No full textPyrethroids are synthetic insecticides possessing greater insecticidal potency and enhanced photostability than plant-derived pyrethrins. Thanks to their low mammalian toxicity and biodegradability, they emerged as a replacement for DDT since the late ’60. The demand for pyrethoids is increasing, also due to the upgraded agriculture technologies of “emerging countries” such as China. Resmethrin was one of the first members of the pyrethroid family to be used. Available preparations of 3 pose an heavy burden on the environment. We present here an alternative route to 1, that avoids the use of 3. A comparative quantitative assessment of the “greenness” of the process will also be shown. Among the several metrics available, we chose to use EATOS ( ) which takes into account both the mass economy and the environmental impact of the materials involved. The assessment was made using a freeware software, available from the authors (6), that produces readily comparable charts
Introducing green metrics early in process development. Comparative assessment of alternative industrial routes to Elliott’s alcohol, a key intermediate in the production of resmethrins.
No full textA comparative assessment between two alternative routes to Elliot’s alcohol, an industrial intermediate in the preparation of pyrethroids of the resmethrin family, is presented in this section. This assessment is made with the aid of the EATOS tool and takes into consideration both the masses (E-factor) as well as environmental impact of the substances employed and released by the processes (Sheldon’s Q)
38. A new economical and environmentally friendly synthesis of 2,5-dimethyl-2,4-hexadiene
No full textA new vapor phase process for the synthesis of 2,5-dimethyl-2,4-hexadiene (or tetramethyl-butadiene) by dehydration of 2,5-dimethyl-2,4-hexadiiol on solid acid catalysts is described. This synthesis is an interesting example of an economical and environmentally friendly process of industrial interest
An old reaction revisited: Vilsmeier-Haack formylation of benzo[1.3]dioxole for the synthesis of heliotropin
No full textComparative assessment of an alternative route to (5-benzylfuran-3-yl)methanol (Elliott's alcohol), a key intermediate for the industrial production of resmethrins
No full textIndustrial preparation of resmethrin, one of the first members of the pyrethroid family to be introduced, is achieved via Elliott's alcohol. Available procedures make use of stoichiometric amounts of pyridine, thionyl chloride, fuming nitric acid and a lot of chlorinated by-products are generated. We present here an alternative route to Elliott's alcohol, based on Baylis–Hillman reaction in aqueous media. A comparative quantitative assessment of the greenness was performed, using the freeware package EATOS which takes into account both the mass economy and the environmental impact of the materials involved
Functionalization of phosphazenes.VII. Photooxidative stabilization of aryloxy-substituted poluorganophosphazenes induced by grafting HALS groups through anhydride moieties
No full textIn this article, the general procedure for stabilizing polyorganophosphazenes against the damage induced in these substrates by photooxidation reactions under accelerated conditions is explored. This method is based on the preventive grafting of succinic anhydride groups onto selected polyphosphazenes induced by light excitation, followed by the reaction of the functionalized phosphazene substrates with amino-terminated HALS groups. HALS moieties, in fact, are able to strongly inhibit the photooxidation of phosphazene films under accelerated conditions even when randomly attached to the polyphosphazene materials in very low amounts
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