Biorenewable Sources Research Articles

Au–Pd Core–Shell Nanoparticles as Alcohol Oxidation Catalysts: Effect of Shape and Composition

The right combination: Shape and composition are two important factors governing the catalytic properties of bimetallic nanocatalysts. Combining gold and palladium in a Au-core–Pd-shell structure coupled with an icosahedral morphology is shown to maximize catalytic performance for the selective oxidation of the biorenewable sources glycerol and 1,2-propanediol to glyceric and lactic acids, respectively.

Economic Feasibility of the Sugar Beet‐to‐Ethylene Value Chain

As part of a long-term strategy toward renewable feedstock, a feasibility study into options for the production of bioethylene by integrating the sugar beet-to-ethanol-to-ethylene value chain. Seven business cases were studied and tested for actual economic feasibility of alternative sugar-to-ethanol-to-ethylene routes in comparison to fossil-fuel alternatives. An elaborate model was developed to assess the relevant operational and financial aspects of each business case. The calculations indicate that bioethylene from sugar beet is not commercially viable under current market conditions. In light of expected global energy and feedstock prices it is also reasonable to expect that this will not change in the near future. To consider biorenewable sources as starting material, they need to be low in cost (compared to sugar beets) and also require less capital and energy-intensive methods for the conversion to chemicals. In general, European sugar prices will be too high for many chemical applications. Future efforts for in sugar-to-chemicals routes should, therefore, focus on integrated process routes and process intensification and/or on products that contain a significant part of the original carbohydrate backbone.

Fatty acid oxidation: systems analysis and applications

Fatty acids (FAs) are essential components of cellular structure and energy-generating routes in living organisms. They exist in a variety of chemical configurations and functionalities and are catabolized by different oxidative routes, according to their structure. α- and ω-Oxidation are minor routes that occur only in eukaryotes, while β-oxidation is the major degradation route in eukaroytes and prokaryotes. These pathways have been characterized and engineered from different perspectives for industrial and biomedical applications. The severity of FA oxidation disorders in humans initially guided the study of FA metabolism at a molecular-level. On the other hand, recent advances in metabolic engineering and systems biology have powered the study of FA biosynthetic and catabolic routes in microorganisms at a systems-level. Several studies have proposed these pathways as platforms for the production of fuels and chemicals from biorenewable sources. The lower complexity of microbial systems has allowed a more comprehensive study of FA metabolism and has opened opportunities for a wider range of applications. Still, there is a need for techniques that facilitate the translation of high-throughput data from microorganisms to more complex eukaryotic systems in order to aid the development of diagnostic and treatment strategies for FA oxidation disorders. In addition, further systems biology analyses on human systems could also provide valuable insights on oxidation disorders. This article presents a comparison of the three main FA oxidative routes, systems biology analyses that have been used to study FA metabolism, and engineering efforts performed on microbial systems.

High-Performance Liquid Chromatography/High-Resolution Multiple Stage Tandem Mass Spectrometry Using Negative-Ion-Mode Hydroxide-Doped Electrospray Ionization for the Characterization of Lignin Degradation Products

In the search for a replacement for fossil fuel and the valuable chemicals currently obtained from crude oil, lignocellulosic biomass has become a promising candidate as an alternative biorenewable source for crude oil. Hence, many research efforts focus on the extraction, degradation, and catalytic transformation of lignin, hemicellulose, and cellulose. Unfortunately, these processes result in the production of very complex mixtures. Further, while methods have been developed for the analysis of mixtures of oligosaccharides, this is not true for the complex mixtures generated upon degradation of lignin. For example, high-performance liquid chromatography/multiple stage tandem mass spectrometry (HPLC/MS(n)), a tool proven to be invaluable in the analysis of complex mixtures derived from many other biopolymers, such as proteins and DNA, has not been implemented for lignin degradation products. In this study, we have developed an HPLC separation method for lignin degradation products that is amenable to negative-ion-mode electrospray ionization (ESI doped with NaOH), the best method identified thus far for ionization of lignin-related model compounds without fragmentation. The separated and ionized compounds are then analyzed by MS(3) experiments to obtain detailed structural information while simultaneously performing high-resolution measurements to determine their elemental compositions in the two parts of a commercial linear quadrupole ion trap/Fourier-transform ion cyclotron resonance mass spectrometer. A lignin degradation product mixture was analyzed using this method, and molecular structures were proposed for some components. This methodology significantly improves the ability to analyze complex product mixtures that result from degraded lignin.

The use of ionic liquids in the processing of chitosan/silk hydrogels for biomedical applications

Natural polymers are adequate renewable resources for the processability of well-defined architectures for several applications. Combinations of polysaccharides and proteins may mimic the naturally occurring environment of certain tissues. The main goal of this work renders the application of green chemistry principles, namely the use of ionic liquids (ILs) and biorenewable sources, such as chitosan (CHT) and silk fibroin (SF), to process new hydrogel-based constructs. Although the solubilization of both materials in ILs has been studied individually, this work reports, for the first time, the role of ILs as solvent, for the production of hydrogels from blends of chitosan and silk fibroin (CSF). These systems offer the advantage of being homogeneous and presenting easy and short dissolution time of both biomacromolecules. Moreover, the use of chitosan obtained from α- and β-chitin allowed the production of blended hydrogels with distinct physical–chemical properties. In vitro assays demonstrated that these hydrogels supported the adhesion and growth of primary human dermal fibroblasts. Taken these properties together, the CSF hydrogels might be promising biomaterials to be explored for skin tissue engineering approaches.

Metal‐Free Dehydration of Glucose to 5‐(Hydroxymethyl)furfural in Ionic Liquids with Boric Acid as a Promoter

The dehydration of glucose and other hexose carbohydrates to 5-(hydroxymethyl)furfural (HMF) was investigated in imidazolium-based ionic liquids with boric acid as a promoter. A yield of up to 42% from glucose and as much as 66% from sucrose was obtained. The yield of HMF decreased as the concentration of boric acid exceeded one equivalent, most likely as a consequence of stronger fructose-borate chelate complexes being formed. Computational modeling with DFT calculations confirmed that the formation of 1:1 glucose-borate complexes facilitated the conversion pathway from glucose to fructose. Deuterium-labeling studies elucidated that the isomerization proceeded via an ene-diol mechanism, which is different to that of the enzyme-catalyzed isomerization of glucose to fructose. The introduced non-metal system containing boric acid provides a new direction in the search for catalyst systems allowing efficient HMF formation from biorenewable sources.

Inhibition of gold and platinum catalysts by reactive intermediates produced in the selective oxidation of alcohols in liquid water

Solid catalysts containing supported nanoparticles of metals such as Au and Pt are very efficient in the oxidation of alcohols obtained from biorenewable sources under mild conditions. However, these reactions sometimes appear to be inhibited by the products formed during oxidation. In this work, the inhibition of glycerol oxidation with O2 by the product glyceric acid over supported Au and Pt catalysts at 333 K in water at high pH was explored in detail. Inhibition was not caused by strong adsorption of product carboxylates on the metal catalyst as anticipated but instead by strong adsorption of ketone intermediates and condensation products of ketones. These reactive intermediates, which can be produced from sugars, sugar alcohols or other oxygenated derivatives of biomass, can severely deactivate metal oxidation catalysts. Thus, high concentrations of these ketonic species should be avoided when processing biomass-derived feedstocks under mild conditions in base.

ChemInform Abstract: Chemoselective Catalytic Conversion of Glycerol as a Biorenewable Source to Valuable Commodity Chemicals

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable commodity chemicals

New opportunities for the conversion of glycerol into value-added chemicals have emerged in recent years as a result of glycerol's unique structure, properties, bioavailability, and renewability. Glycerol is currently produced in large amounts during the transesterification of fatty acids into biodiesel and as such represents a useful by-product. This paper provides a comprehensive review and critical analysis on the different reaction pathways for catalytic conversion of glycerol into commodity chemicals, including selective oxidation, selective hydrogenolysis, selective dehydration, pyrolysis and gasification, steam reforming, thermal reduction into syngas, selective transesterification, selective etherification, oligomerization and polymerization, and conversion of glycerol into glycerol carbonate.

Solvents from Biorenewable Sources: Ionic Liquids Based on Fructose

Solvents from Biorenewable Sources: Ionic Liquids Based on Fructose

Greener Solvents: Room Temperature Ionic Liquids from Biorenewable Sources

AbstractRoom temperature ionic liquids (RTILs) have attracted a great deal of interest as environmentally benign (green) solvents for organic synthesis. More recently, RTILs that are chiral, less expensive, or functionalized (protic or Lewis basic) have been developed. In many cases, these new solvents are based on the modification of natural products. This paper is an overview of these new biorenewable RTILs.

Solvents from biorenewable sources: ionic liquids based on fructose.

[reaction: see text] Fructose has been used as the starting material for the preparation of a new class of room-temperature ionic liquids (RTILs). These liquids exhibit tunable solvent properties much like conventional imidazole-based RTILs. They have been applied as recyclable solvents for the Heck reaction of aryl iodides.

The synthesis and cationic polymerization of novel monomers from renewable sources

AbstractThis communication describes recent developments in this laboratory directed towards the design of cationically polymerizable monomers from biorenewable sources. Three classes of ubiquitous biorenewable substrates were explored, namely: lipids, carbohydrates and terpenes. Considered in the synthesis and design were the cost and availability of the substrates, and the practicality and environmental acceptability of the chemical methodology. The polymerizations of the monomers were carried out using photoinitiated cationic polymerization.