CaO as Drop‐In Colloidal Catalysts for the Synthesis of Higher Polyglycerols |
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| Authors: | Dr Fiona Kirby Anne‐Eva Nieuwelink Bonny W M Kuipers Dr Anton Kaiser Dr Pieter C A Bruijnincx Prof Dr Bert M Weckhuysen |
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| Institution: | 1. Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands);2. Van ‘t Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht (The Netherlands);3. Clariant Competence Center Surfactants, Industrieparkstrasse 1, 84508 Burgkirchen (Germany) |
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| Abstract: | Glycerol is an attractive renewable building block for the synthesis of polyglycerols, which find application in the cosmetic and pharmaceutical industries. The selective etherification of glycerol to higher oligomers was studied in the presence of CaO colloids and the data are compared with those obtained from NaOH and CaO. The materials were prepared by dispersing CaO, CaCO3, or Ca(OH)2 onto a carbon nanofiber (CNF) support. Colloidal nanoparticles were subsequently dispensed from the CNF into the reaction mixture to give CaO colloids that have a higher activity than equimolar amounts of bulk CaO and NaOH. Optimization of the reaction conditions allowed us to obtain a product with Gardner color number <2, containing no acrolein and minimal cyclic byproducts. The differences in the CaO colloids originating from CNF and bulk CaO were probed using light scattering and conductivity measurements. The results confirmed that the higher activity of the colloids originating from CaO/CNF was due to their more rapid formation and smaller size compared with colloids from bulk CaO. We thus have developed a practical method for the synthesis of polyglycerols containing low amounts of Ca. |
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| Keywords: | calcium colloids heterogeneous catalysis nanostructures oligomerization |
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