
handle: 10174/11816
O aumento da produção e utilização do biodiesel tem resultado num aumento da quantidade de glicerol produzida. Torna-se assim, imperativo desenvolver novas utilizações para o glicerol, de forma a evitar problemas ambientais. Uma possibilidade é a condensação do glicerol com acetona. Esta reacção foi realizada com ácido dodecatungstofosfórico (PW) imobilizado em SBA-15, a 70 ºC. Os catalisadores foram preparados com diferentes quantidades de heteropoliácido (1,8-10,8 wt.%). Observou-se que a actividade catalítica aumenta com a quantidade de PW imobilizada em SBA-15, sendo o catalisador PW4-SBA-15 (com 10,8 wt.%) a amostra mais activa. Todos os catalisadores apresentaram bons valores de selectividade para Composto A (cerca de 99% próximo da conversão completa). A estabilidade catalítica da amostra PW4-SBA-15 foi avaliada através da realização de três ensaios consecutivos. Observou-se que, após a terceira utilização, a actividade catalítica estabilizou. Foi também observado uma pequena lixiviação do heteropoliácido para a acetona; ### Abstract: The increase of use and production of biodiesel has resulted in an increase of glycerol. It is imperative to develop new uses for glycerol to prevent environmental problems. A possibility, it is the condensation of glycerol with acetone. This reaction was carried out using dodecatungstophosphoric acid (PW) immobilized in SBA-15, at 70ºC. A series of catalysts, with different heteropolyacid loading (from 1.8 to 10.8 wt. %), were prepared. It was observed that the catalytic activity increases with the amount of PW immobilized in SBA-15, being the PW4-SBA-15 (with 10.8 wt. %) the most active sample. All catalyst exhibited good values of selectivity to Composto A (about 99% near complete conversion). Catalytic stability of the PW4-SBA-15 was evaluated by performing consecutive batch runs with the same catalyst sample. It was observed that, after the third use, the catalytic activity stabilized. It was also observed a small leaching of heteropolyacid from SBA-15 to acetone.
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 0 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
