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The use of renewable sources for obtainment of chemicals, biofuels, materials and energy has become each time larger due to environmental, political and economical problems of non-renewable energies utilization. Among several products that can be obtained from lignocellulosic biomass, which is a renewable source, there is furfural, a chemical from which many other value added chemical products can be obtained. The main route for furfural production consists of an acid hydrolysis of hemicelluloses present in lignocellulosic biomass to obtain xylose, which goes through a dehydration reaction to produce furfural. Due to the presence of an aldehyde group and a conjugated system of double bounds, furfural can go through several reactions, allowing the production of a range of value added products. In this sense, this article performs a review about mechanisms of furfural production from lignocellulosic biomass, highlighting its chemical properties which enable its utilization in different industrial applications of economic interest.

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This work presents a comparative study between alternative catalytic systems, metal-b-diketones complexes (iron, copper, chromium, and tin), and the commercial catalyst dibutyltin dilaurate, DBTDL, in the polyurethanes synthesis obtained from isophorone diisocyanate (IPDI) and polyols as polypropyleneglycol/diethyleneglycol and 1,6-hexanodiol polyadipate (polyester A-Mn ¼ 2000 g/ mol and polyester B-Mn ¼ 1000 g/mol) reactions. The polyurethanes synthesis was followed by the IPDI consumption in time, verified by infrared spectroscopy (FTIR) through the decrease of free NCO characteristic band at 2300-2200 cm À1. The FTIR data was used to determine the polyurethanes formation kinetic behavior. It was verified that for the reactions with polyethers excess, DBTDL catalyst was more effective when compared to metal-b-diketones complexes, while for the reactions with polyester, A and B, the metal-b-diketones complexes were more effective.

The transesterification of rice bran oil with methanol has been studied in the presence of sulfuric acid (H2SO4), tin chloride dihydrate (SnCl2·2H2O), tin 2-ethylhexanoate (Sn(C8H15O2)2), dibutyl tin oxide ((C4H9)2SnO), and dibutyl tin dilaurate ((C4H9)2Sn(C12H23O2)2), known commercially as DBTDL. Through the comparative analysis among the catalysts, we observed that the complex DBTDL presented the best performance, with a yield of 68.9% in 4 h using molar ratio 400:100:1 (methanol:oil:catalyst). These results evidenced the viability of the use of metallic compounds as catalysts in the obtainment of biodiesel, an interesting alternative to basic and acid catalysis.