The best conditions for the kinetic study of the ketalization reaction of glycerol with acetone for the production of solketal using zeolite H-BEA (SAR 19) as a catalyst were found through a fractional experimental design. To simplify the heterogeneous kinetics, by means of a smaller number of kinetic parameters to encompass all the kinetic terms toward the products and reagents, a reversible kinetic model was used. From the comparison between the experimental and calculated conversions, it was possible to analyze the accuracy of the estimations, providing a good way to apply statistical treatments to improve the calculated kinetic properties. Thereby, it is possible to calculate the equilibrium constants for a range of reactions performed across different temperatures (40−80 °C) as well as the forward reaction activation energy (44.77 kJ mol −1 ) and the reverse reaction activation energy (41.40 kJ mol −1 ). Moreover, 70−76% glycerol conversion was obtained using the same catalyst for five reactions, without wash or performing any other pretreatments in the catalyst between reactions. The solketal product has been studied as a green industrial solvent additive in gasoline and biofuels.

The use of graphitic carbon nitride (g‐C3N4)‐based catalysts in the upgrading of lignocellulosic biomass significantly contributes to the greener production of biofuels, polymer precursors, and building blocks. In recent years, several catalysts based on g‐C3N4 have been developed and applied in both photocatalyzed and non‐photocatalyzed (thermal) reactions. This Review provides an overview on the upgrading of lignocellulosic biomass deploying several compositions of g‐C3N4‐based catalysts.

No abstract

Commercial solketal is known as Augeo™ SL 191 and is produced by Rhodia (a member of the Solvay Group), which stands out as a slow evaporation solvent derived from glycerin which is considered a renewable source. It has low toxicity to human health and the environment. It is a good solvent for resins and polymers, replacing solvents derived from petroleum, and can be used as an additive of (bio) fuels. This work aimed to study acidy zeolites (H-BEA, H-MOR, H-MFI, and H-FER) as new heterogeneous catalysts of solketal production, through the ketalization reaction of glycerol with acetone. The catalytic activity showed H-BEA > H-MOR = H-MFI > H-FER after 180 min, in kinetics study. The major conversion was 85% for H-BEA. It was also verified that all the catalysts can be reused four times without washing or pretreatment among reactions in batch reactor. The solketal produced in this work was characterized by comparing it with its commercial standard, obtaining very similar characteristics.

The development of more efficient and greener catalytic strategies for the upgrading of biomass to value-added chemicals is crucial to achieve a more sustainable future. In recent years, cutting-edge single-atom...

Food packaging based on nanotechnology of polymeric nanocomposites of graphene and graphene oxide results in packaging with better thermal, mechanical, antimicrobial, electrical packaging, moisture barrier and gas properties.

A BRIEF OVERVIEW ON SINGLE-ATOM CATALYSIS: CONCEPTS AND APPLICATIONS. Catalytic processes became extremely important for the development of our society, especially after the second industrial revolution. Thus, the research for more efficient catalysts is an obstacle to overcome to achieve cheaper processes, higher yields, and selectivity of desired products. In this context, single-atom catalysis emerges as a promising alternative to unite the advantages of traditional homogeneous and heterogeneous catalysis. Catalysis by single-atoms is a bridge that unites in a single catalyst the ease of recovery and reuse (from heterogeneous catalysis) with the high exposure and uniformity of sites (from homogeneous catalysis). Thus, single-atom catalysts (SACs) and single-atom alloys (SAAs) have already found several applications in the literature, such as in hydrogenation, oxidation, conversion of biomass derivatives, electrocatalysis, and photocatalysis. However, it is essential to emphasize that it is still a field that is expanding and relatively new, with several opportunities and many barriers to surpass. In this review, concepts of homogeneous, enzymatic, and heterogeneous catalysis will be addressed, as well as fundamental aspects of single-atom catalysis, preparation methods, characterization, and current challenges.

Renewable hydrocarbons refer to fuels consisting of hydrocarbons of 10 to 20 carbon atoms, produced from biomass, and free of oxygen. Hydrocracking, hydrodeoxygenation and hydrotreatment processes for the production of renewable hydrocarbons are described in the literature. Microalgae have been targeted in recent years to synthesize biomass that can be used in the production of biofuels, such as renewable hydrocarbons, biodiesel or ethanol second generation. In this context the lineage Monoraphidium sp. was selected from previous ecophysiological studies and its potential to produce lipids to develop this research related with the extraction of the bio-oil of the wet biomass of Monoraphidium sp. through heat treatment. Consecutively the bio-oil was used as raw material for the production of hydrocarbons through hydrocracking and hydrodeoxygenation processes (HDO) as: decarbonylation, decarboxylation, dehydratation, with in situ production of hydrogen from liquid-phase reforming of glycerol. The reactions were carried out under two different temperature conditions, 350˚C and 300˚C, respectively, for 1 h and using ruthenium alumina catalyst (Ru/Al 2 O 3). The results showed the bio-oil processing route at a temperature of 350˚C promising for the production of hydrocarbons achieving a conversion of 81.54%.