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Carbon-carbon cross-coupling reactions are among the most important processes in organic chemistry, and Suzuki-Miyaura reactions are among the most widely used protocols for the formation of carbon-carbon bonds. These reactions are generally catalyzed by soluble palladium complexes with various ligands. However, the use of toxic organic solvents remains a scientific challenge and an aspect of economical and ecological relevance. This Review will summarize various recently developed significant methods by which the Suzuki-Miyaura coupling was conducted in aqueous media, and analyzes if they are "real green" protocols.

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Biobased production of furfural has been known for decades. Nevertheless, bioeconomy and circular economy concepts is much more recent and has motivated a regain of interest of dedicated research to improve production modes and expand potential uses. Accordingly, this review paper aims essentially at outlining recent breakthroughs obtained in the field of furfural production from sugars and polysaccharides feedstocks. The review discusses advances obtained in major production pathways recently explored splitting in the following categories: (i) non-catalytic routes like use of critical solvents or hot water pretreatment, (ii) use of various homogeneous catalysts like mineral or organic acids, metal salts or ionic liquids, (iii) feedstock dehydration making use of various solid acid catalysts; (iv) feedstock dehydration making use of supported catalysts, (v) other heterogeneous catalytic routes. The paper also briefly overviews current understanding of furfural chemical synthesis and its underpinning mechanism as well as safety issues pertaining to the substance. Eventually, some remaining research topics are put in perspective for further optimization of biobased furfural production.

Furfural has been considered as one of the most promising platform molecules directly derived from biomass. The hydrogenation of furfural is one of the most versatile reactions to upgrade furanic components to biofuels. For instance, it can lead to plenty of downstream products, such as (tetrahydro)furfuryl alcohol, 2-methyl(tetrahydro)furan, lactones, levulinates, cyclopentanone(l), or diols, etc. The aim of this review is to discuss recent advances in the catalytic hydrogenation of furfural towards (tetrahydro)furfuryl alcohol and 2-methyl(tetrahydro)furan in terms of different non-noble metal and noble metal catalytic systems. Reaction mechanisms that are related to the different catalytic materials and reaction conditions are properly discussed. Selective hydrogenation of furfural could be modified not only by varying the types of catalyst (nature of metal, support, and preparation method) and reaction conditions, but also by altering the reaction regime, namely from batch to continuous flow. In any case, furfural catalytic hydrogenation is an open research line, which represents an attractive option for biomass valorization towards valuable chemicals and fuels.FA is a very important monomer for the synthesis of furan resins, which are widely used in thermoset polymer matrix composites, cements, adhesives, coatings, and casting/foundry resins. This molecule is also used as a non-reactive diluent for epoxy resin, a modifier for phenolic and urea resins, an oil well, and a carbon binder. Furthermore, the salt of FA is used in the synthesis of lysine, vitamin C, lubricants, and plasticizers [22,23]. Moreover, it should be highlighted that FA is also an important intermediate for the production of further hydrogenation products (as shown in Scheme 1), such as 2-methylfuran (MF), a potential alternative fuel with better combustion performance and higher Research Octane Number (RON = 103) than that of gasoline (RON = 96.8) [24]. In other applications, MF is used in perfume intermediates, chloroquine lateral chains in medical intermediates, and as a raw material for the production of chrysanthemate pesticides [25].Moreover, tetrahydrofurfuryl alcohol (THFA) can be used as a green solvent in the pharmaceutical industry and, in addition, it constitutes an outstanding intermediate to produce dihydropyran [26], pyridine [27], tetrahydrofuran, and pentan-1,5-diol [28][29][30]. Particularly, the latest molecule is an important monomer in the plastics industry. Furthermore, 2-methyltetrahydrofuran (MTHF) is quite engaging for its possible applications in organometallic chemistry, as well as in organic reactions that are related to organocatalysis, biotransformations, and biomass processing [31]. Catalysts 2019, 9, 796 3 of 33 Catalysts 2018, 8, x FOR PEER REVIEW 3 of 36 Scheme 1. Illustrative representation of reaction pathways in furfural hydrogenation.Other downstream products of furfural hydrogenation, such as (tetrahydro)furan [32], tetrahydrofurfural [33], lactones [34][35][36][37], levulinates [38,39], cyclopentanone...

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Sulfonic acid based mesostructures (SAMs) have been developed in recent years and have important catalytic applications. The primary applications of these materials are in various organic synthesis reactions, such as multicomponent reactions, carbon–carbon bond couplings, protection reactions, and Fries and Beckman rearrangements. This review aims to provide an overview of the recent developments in the field of SAMs with a particular emphasis on the reaction scope and advantages of heterogeneous solid acid catalysts.