| 摘要 |
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°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 |
