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REAÇÃO DE CONDENSAÇÃO DO GLICEROL COM COMPOSTOS CARBONÍLICOS. SÍNTESE, CARACTERIZAÇÃO E APLICAÇÃO EM CRISTAIS LÍQUIDOS
- Source :
- Química Nova, Vol 38, Iss 8, Pp 1053-1062 (2015)
- Publication Year :
- 2015
- Publisher :
- Sociedade Brasileira de Química, 2015.
-
Abstract
- Condensation reactions of glycerol with aldehydes and ketones were performed under thermal heating and microwave irradiation regimes. Homogeneous and heterogeneous catalysts were tested in both conditions. A silica sulfated (SiO2-SO3H) heterogeneous catalyst demonstrated the best performance relative to a selectivity of >95% in favor of 5-membered ketals. For acetals, preference in favor of 5-membered or 6-membered functional groups depends on the nature of the catalyst. Homogenous catalysts favor the more stable 6-membered acetals, whereas heterogeneous catalysts favor the less stable 5-membered acetals. However, the isomer ratios in the acetalization reaction are too low, and hence the reaction cannot be used in a synthetic plan for functional materials. Ketalization processes mediated by SiO2-SO3H show a high selectivity in favor of a 5-membered ring (1,3-dioxolane). The scope of condensation was tested with different ketones. A mechanism for heterogeneous catalysis related to the selectivity in the cyclization process is presented herein. Solketal, a commercial product, was also obtained by a condensation reaction of glycerol and propanone, and showed a high selectivity in favor of 1,3-dioxolane. It was transformed to potential allylic and chiral intermediates. A mesogenic core was connected to the organic framework of glycerol to produce a monomer liquid crystal material with a stable smectic-C mesophase.
Details
- Language :
- English, Spanish; Castilian, Portuguese
- ISSN :
- 16787064 and 01004042
- Volume :
- 38
- Issue :
- 8
- Database :
- Directory of Open Access Journals
- Journal :
- Química Nova
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.4c27bbc479a84e25aec36e7adac38014
- Document Type :
- article
- Full Text :
- https://doi.org/10.5935/0100-4042.20150111