نتایج جستجو برای: glycols
تعداد نتایج: 14974 فیلتر نتایج به سال:
New macrocyclic polyether-diester ligands (3-5) containing the 4H-pyran-4-one subcyclic unit have been prepared by treating various glycols with dimethyl chelidonate (10). In the reaction of compound 10 with ethylene glycol and diethylene glycol, two noncyclic diester and tetraester (6-9) were produced in each case. The new marcocyclic ligand 4 formed stable complexes with benzylammonium pe...
Ruthenium(II) PNN complexes depolymerize many polyesters into diols and polycarbonates into glycols plus methanol via hydrogenation. Notably, polyesters with two methylene units between ester linkages depolymerize to carboxylic acids rather than diols. This methodology represents a new approach for producing useful chemicals from waste plastics.
The present work concerns on the investigation of the role of polyethylene glycols (PEGs) as masking agent for amelioration of extraction-separation of La(III), Eu(III) and Er(III) ions by the acidic extractant bis(2-ethylhexyl)phosphoric acid (DEHPA). The studied solvent extraction system is based on the combination of chelating effect of DEHPA in the organic phase on the one hand, and the bin...
new macrocyclic polyether-diester ligands (3-5) containing the 4h-pyran-4-one subcyclic unit have been prepared by treating various glycols with dimethyl chelidonate (10). in the reaction of compound 10 with ethylene glycol and diethylene glycol, two noncyclic diester and tetraester (6-9) were produced in each case. the new marcocyclic ligand 4 formed stable complexes with benzylammonium perchl...
A mild and efficient method for the synthesis of optically active α-hydroxy acids through chemoselective oxidation of monosubstituted ethylene glycols using the TEMPO-NaOCl reagent system is described. It is evident from our studies that the solvent, pH and reaction temperature are very crucial for the success of this oxidation. The versatility of this method has been demonstrated with a variet...
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