Processo de solubilização, hidrólise e degradação de celulose e derivados em presença de catalisadores metálicos a base de Sn(IV)

Abstract

Nowadays, petrol of easy exploitation is becoming scarcer, which can lead to higher prices of its derivatives and/or a deficiency of petrochemical raw materials on the market. In addition, the dependence reduction of non-renewable sources, based on petrol, is a desired of the contemporaneous society, in which the "green chemistry” concept is closely connected to the search of chemical products and/or processes associated to the use of clean technologies and to the sustainable development. Consequently, many efforts have been employed in order to obtain new renewable source that can replace partial or completely the petrol as input supply of chemicals and energy, and in this context, lignocellulosic biomass has a great potential. The processes of hydrolysis and degradation of lignocellulosic biomass, especially from cellulose, may occur in the presence of acidic, basic or enzymatic catalytic systems. However, these processes have some drawbacks that compromise their economical viability. In this context, the hydrolysis of cellulose catalyzed by metals and derivative compounds has attracted great interest of several research groups. These catalytic systems display na enormous potential in terms of activity and selectivity, as well in the development of chemical products and/or processes that are associated with the use of clean technologies (“green” catalytic processes). The aim of this study was to apply and evaluate catalytic systems based on Sn(IV) complexes in the conversion of crystalline cellulose in to hydrolysis or degradation products, as well, in to more soluble materials that can conduct lately conducted to more valuable product. The activity and selectivity of these catalysts were evaluated in comparison to reactions performed with sulfuric acid as catalyst and without catalyst, at 150ºC and 190ºC and several reaction times. The catalytic systems based on Sn(IV) exhibit good performance in the process of hydrolysis and degradation of cellulose, and for all reactions carried out at 190 º C was observed the formation of glucose and 5-hydroxymethylfurfural (HMF). Besides that, a large content of no identified product was detected by HPLC, which were not detected at significant levels in reactions performed in the presence of sulfuric acid or without catalyst.