- Zinc-catalyzed depolymerization of polyethers to produce valuable building blocks
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The recycling of polymers continues to be a significant matter for a sustainable society. In particular, the conversion of end-of-life polymers to monomers or suitable low-molecular weight chemicals creates a feedstock for new high-quality polymeric materials and contributes to conserve resources and allow overall an efficient waste-managing system. In the present study, we have set up a straightforward methodology for the depolymerization of artificial polyethers applying cheap and abundant zinc( II) salts as precatalysts. In the presence of bio-based fatty acid chlorides as depolymerization reagent well-defined chloroesters were accessible in good to excellent yields. Moreover, acetic anhydride and fatty acids were applied as depolymerization reagents resulting in the formation of diacetates in moderate yields. In both cases the obtained products (chloroesters, diacetates) can be useful building blocks in polymerization chemistry. Noteworthy, overall a recycling of polyethers are possible. Springer Science+Business Media New York 2014.
- Enthaler, Stephan
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p. 850 - 859
(2014/06/23)
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- Sustained release pharmaceutical compositions
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The present invention relates to a pharmaceutical composition comprising a salt of quaternary ammonium of an acid drug in the form of a suspension or an emulsion, suitable for parenteral administration and providing a sustained release of the drug. In one preferred embodiment, the present invention is directed to a long term sustained release composition for parenteral administration, comprising a salt of heparin or low molecular weight heparin in an emulsion with a salt of acylcholine, for the prevention and treatment of venous thrombosis and pulmonary embolism.
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Page/Page column 4-5
(2008/06/13)
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