Method for the production of hyperbranched polyglycerol

Abstract

The present invention concerns a process for producing hyperbranched, dendritic polyglycerol from glycerol comprising the following steps: (a) adding in a vessel glycerol and a CaO-based catalyst, (b) flushing an inert gas, preferably carbon dioxide, to the resulting mixture and hermetically closing the reaction vessel, allowing pressure to build up from 1 to 10 bar above atmospheric, preferably from 2 to 6 bar; (c) heating the reaction mixture at a reaction temperature of at least 100 DEG C and below its boiling point; (d) maintaining the reaction conditions until at least 40 wt.% of glycerol is polycondensed and converted into hyperbranched polyglycerol, with concomitant water formation,, (e) separating the dendritic polyglycerol from other components present in the mixture; such as water, catalyst and reaction by-products such as hydroxyacids and glycerol carbonate esters obtained by condensation of deprotonated glycerol and carbon dioxide as well as minor amounts of cyclic compounds. (i) characterized in that, the calcium based catalyst is nanostructured calcium oxide in the form of a powder of mean particle size smaller than 100 nm measured according to ASTM D4464

Description

technical field [0001] The invention relates to a method for polycondensing glycerol to produce hyperbranched polyglycerol in the presence of a specific catalyst. Background technique [0002] Hyperbranched polyglycerol (hbPG) is a highly branched polyol with an inert polyether backbone, whose high functionality combined with the versatile and well-known reactivity of its hydroxyl functionality forms the basis for a variety of useful derivatives ( See Frey, H. and Haag, R., "Dendritic Polyglycerol: A New Versatile Biocompatible Material," Rev. Mol. Biotech, 90 (2002) 257-267). Each branch is terminated with hydroxyl functionality, which makes hyperbranched polyglycerol a highly functional material; for example, a molecular weight of 5,000 g mol –1 The molecule of can have 68 hydroxyl end groups. Many polyglycerols are commercially available, with applications ranging from cosmetics to drug controlled release. For example, partial esterification of polyglycerol with fatty ...

AI Technical Summary

Problems solved by technology

The special properties of similar nanostructured CaO for the etherification of glycerol to diglycerol at 220 °C in Ar in the absence of solvents have been recently reported (cf. "Glyceroletherification over highly active CaO-based materials: new mechanistic aspects and related colloidal particle formation", Chem.Eur.J.14(2008)2016-2024), while commercially available CaO has poor activity

To the best of our knowledge, no route to hyperbranched polyglycerols based on conventional or nanostructured CaO catalysts has been reported.

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