Measurement of free glycerol in biofuels

A method has been developed to determine the free glycerol content in esters derived from vegetable oils. After extraction of glycerol, its measurement in small quantities in biofuels (methyl or ethyl esters) is possible by high-pressure liquid chromatography combined with pulsed amperometric detection, HPLC-PAD. The method has proved to be simple, rapid and accurate. The limit of detection is 1 g/g.     

Measurement of free glycerol in biofuels

A method has been developed to determine the free glycerol content in esters derived from vegetable oils. After extraction of glycerol, its measurement in small quantities in biofuels (methyl or ethyl esters) is possible by high-pressure liquid chromatography combined with pulsed amperometric detection, HPLC-PAD. The method has proved to be simple, rapid and accurate. The limit of detection is 1 microg/g.     

Pretreatment processes for lignocellulosic biomass conversion to biofuels and bioproducts

Lignocellulosic materials, such as forestry, agricultural and agroindustrial residues, are among the most important sources of biomass for the production of fuels, chemicals and materials. However there are physical and chemical barriers in the lignin–carbohydrate supramolecular structure that render most plant cell wall components almost completely unavailable for conversion into commercial products. Thus successful conversion strategies must lead to the disruption of this structure and result in partial or total separation of the lignocellulosic components, increasing the accessibility of cellulose, hemicelluloses and lignins. It must also minimize the formation of by-products. Each pretreatment technology has its own characteristics and is usually applied to a specific source of carbohydrates and lignins. A general overview of the most important pretreatment methods for the production of platform chemicals and fermentable sugars are given in this paper.     

Heat of combustion of biofuels mixed with fossil diesel oil

The Brazilian government has presented a biofuel program, which aims the addition of 2% of biofuel in fossil diesel in 2008 and 5% up to 2013. Thus, the knowledge of heat of combustion of biofuel/diesel blends is necessary. The biodiesel was produced by transesterification of soybean oil with a yield of 87%. The diesel-like was obtained by pyrolysis of soybean oil. This biofuel presented all parameters according to ANP. The obtained heats of combustion were 41.36 ± 0.17; 38.70 ± 0.16; and 36.71 ± 0.17 MJ/kg for diesel, diesel-like and biodiesel, respectively. The results show that the heats of combustion of biofuels are approximately 17% smaller than fossil diesel. The obtained data also show that the heats of combustion depend on the methodology used for the biofuel production. Addition of biofuels to traditional diesel fuel results in a linear decreasing of the heat of combustion with the amount of the alternative fuel added to the diesel.     

Use of biofuels to produce hydrogen (reformation processes)

This tutorial review deals with the catalytic reformation of ethanol and glycerol to produce hydrogen that can be used as an energy carrier in a fuel cell. Both the worldwide production of ethanol in large amounts to be used as a biofuel and that of glycerol as a by-product in biodiesel manufacture are presented. The catalytic reformation processes of both ethanol and glycerol are contemplated, including thermodynamic and kinetic aspects. Catalysts are analyzed as a function of operation conditions, selectivity and stability.     

Supramolecular self-assembled chaos: polyphenolic lignin's barrier to cost-effective lignocellulosic biofuels

Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous self-assembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and non-representative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs) also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, lignin-polysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production.     

Lignocellulosics to biofuels: An overview of recent and relevant advances

1. Download : Download high-res image (178KB)
2. Download : Download full-size image

     

Alternative antifouling biocides

In response to increasing scientific evidence on the toxicity and occurrence of organotin residues from antifouling paints in the aquatic environment, the use of triorganotin antifouling products was banned on boats of less than 25 m length in many countries during 1987. The use of tributyltin (TBT) products on small boats was superseded by products based on copper, containing organic booster biocides to improve the efficacy of the formulation. Available information and evidence on the occurrence, fate and toxicity of these biocides is reviewed. It is concluded that increased copper concentrations in the aquatic environment, due to the increased use of copper‐based antifoulants, do not have significant effects on marine ecosystems. However, lack of validated analytical methods, limited monitoring data, and very little information about the fate and toxicity of the booster biocides in the aquatic environment, make accurate risk assessments in relation to these compounds difficult. Copyright © 1999 John Wiley & Sons, Ltd.     

High-silica faujasite zeolite-tailored metal encapsulation for the low-temperature production of pentanoic biofuels

Zeolite-encapsulated metal nanoclusters are at the heart of bifunctional catalysts, which hold great potential for petrochemical conversion and the emerging sustainable biorefineries. Nevertheless, efficient encapsulation of metal nanoclusters into a high-silica zeolite Y in particular with good structural integrity still remains a significant challenge. Herein, we have constructed Ru nanoclusters(～1 nm) encapsulated inside a high-silica zeolite Y(SY) with a SiO₂/Al₂O_3...     

Optimal blending to improve the combustibility of biofuels: a waste-to-energy approach

Journal of Thermal Analysis and Calorimetry - Increasing awareness due to climate change have been stimulating the development of renewable energies. Slow pyrolysis is considered a good method to...     

Alternative synthesis of alverine

An efficient synthesis of alverine via iron-catalyzed double cross-coupling of (2E)-3-chloro-N-[(2E)-3-chloroprop-2-en-1-yl]-N-ethylprop-2-en-1-amine with phenylmagnesium bromide is described.     

Alternative bacteriophage display systems

Filamentous phage has been extensively used to implement various aspects of phage display technology. The success of these organisms as vectors to present foreign peptides and to link them to their coding sequences is a consequence of their structural and biological characteristics. Some of these properties, however, represent a limitation when one attempts to display proteins that cannot be efficiently exported through the bacterial membrane or do not fold properly in the periplasm. Thus, the desirability of developing alternative display systems was recognised recently and led to the development of a different class of display vectors that assemble their capsid in the cytoplasm and are released via cell lysis. This review describes and compares the properties of these alternative display systems.