Catalytic Methods in Flow Chemistry

The chemical industry is essential in the daily humn life of modern society; despite the misconception about the real need for chemical production, everyone enjoys the benefit of the chemical progress. However, the chemical industry generates a large variety of products, including (i) basic chemicals, e.g., polymers, petrochemicals, and basic inorganics; (ii) specialty chemicals for crop protection, paints, inks, colorants, textiles, paper, and engineering; and (iii) consumer chemicals, including detergents, soaps, etc. For these reasons, chemists in both acdemia and industry are challenged with developing green and sustainable chemical production towrad the full-recycling of feedstocks and waste. Aiming to improve the intensification of the process, chemists have established chemical reactions based on catalysis, as well as alternative technologies, such as continuous flow. The aim of this book is to cover promising recent research and novel trends in the field of novel catalytic reactions (homogeneous, heterogeneous, and enzymatic, as well as their combinations) in continuous flow conditions. A collection of recent contribution for conversion of starting material originated from petroleum resources or biomass into highly-added value chemicals are reported

Sulfonated sporopollenin as an efficient and recyclable heterogeneous catalyst for dehydration of D-xylose and xylan into furfural

The natural acidity of sporopollenin, the biopolymer coating the outer walls of pollen grains, was enhanced by the sulfonation of its surface. Modified sporopollenin displaying sulfonic acid groups has been prepared, characterized by elemental analysis, SEM, EDX, FTIR and XPS and tested as a heterogeneous catalyst in the dehydration of D-xylose and xylan to produce furfural. The optimal reaction conditions involve 10 wt % of sulfonated sporopollenin in the presence of 1.5 mmol of NaCl in a biphasic water-CPME system. When heated at 190 °C, the reaction affords furfural in a yield of 69% after 40 min under microwave irradiation. The time dependence of the dehydration and influence of temperature, pentose loading and positive effect of chloride ions on the reaction rate are reported. It was found that the catalytic system, recharged with the pentose and solvent, could be recycled ten times without loss of performance. The transformation of xylan into furfural at 190 °C for 50 min gave furfural in a yield of 37%

A Novel Strategy for Selective O-Methylation of Glycerol in Subcritical Methanol

A new regioselective approach has been elaborated for the selective conversion of bio-based glycerol into the monomethyl derivative using sub/supercritical methanol. The reaction was realized in a batch process using three reactive components, namely, glycerol, methanol, and potassium carbonate to selectively produce the 3-methoxypropan-1,2-diol in mild yields; the mechanism of the O-methylation has been delineated using labeled methanol and GC-MS experiments

Editorial

peer reviewedEditorial for the special issue on biobased flow chemistr

An insight of combustibility induced safety issues pertaining to ionic liquids

International audienceThis study is a consolidated overview on explosion and fire safety issues pertaining to ionic liquids. Indeed safety performance of ionic liquids relating to physico-chemical hazards is very rarely investigated as it is often perceived as a non-existing issue due to the lack of traditional flashpoint for these liquids. It focuses on the experimental evaluation of the fire hazard of imidazolium, phosphonium and pyrrolidinium-based ionic liquids by use of the Fire Propagation Apparatus. It provides experimental data that can quantify the flammability of ionic liquids in all its aspects (ease of ignition, mass burning rate, heat release rate, fire-induced toxicity data...). A case study featuring a major failure in a process unit leading to a given fire scenario is also illustrated. This case study is examined in terms of fire induced toxicity by use of CFD modeling of fire product releases dispersion and using the concept of fractional effective concentration

Catalyse dans l'eau appliquée à la synthèse de nucléosides ciblés

De nombreux nucléosides modifiés sont rapportés dans la littérature comme ayant une activité antibactérienne, antitumorale ou antivirale. Parmi ces derniers, la BVDU, est utilisée pour lutter contre le virus de l'herpès. Dans l'optique de réaliser des analogues de ce composé nous avons mis au point des méthodes de synthèse de composés de type 5-aryl-2-désoxyuridine. La synthèse de tels composés est souvent décrite via des réactions organo-palladées mais dans des conditions mettant en jeu des solvants organiques. La mise au point d'une méthodologie de synthèse de ces composés via la réaction de Suzuki-Miyaura dans l'eau pure a été réalisée. Des analogues de type 5-aryluridine et 6-aryluridine ont été synthétisés en utilisant des conditions similaires. L'importance du ligand, très souvent utilisé dans ce type de réaction, a été remise en cause, car nous avons montré que les composés peuvent être obtenus avec de très bon rendements en son absence. L'activation par irradiation micro-ondes a aussi été utilisée. Elle a permis d'obtenir les produits de couplage avec de bons rendements dans des temps de réactions très courts. En parallèle de ces travaux, dans l'optique d'une collaboration avec un laboratoire indien, la synthèse de composés de type5-allyluridine et 5-alllyl-2'-désoxyuridine a été étudiée.Many nucleosides analogues are reported in literature as antitumor, antibacterial or antiviral. Among them, the BVDU, is used as a drug against the herpes virus. In order to synthesize derivates of this compounds, we decided to develop new synthetic routes of 5-aryl-2'-deoxyrudine analogues. The synthesis of such compounds is widely described in literature using cross-coupling reaction with palladium but they often use organic solvents. A methodology to synthesize these analogues using the Suzuki-Miyaura reaction, in water, has been developed. 5-aryluridine and 6-aryluridine derivates were also synthetized using a similar methodology. The relevance of the ligand, commonly used in organo-palladated reactions, was studied. In our hands, the target compounds were obtained in good yiels using a free ligand methodology. Micro-wave activation was also studied. It allowed the synthesis of the nucleosides in good yields within very short reaction times. In collaboration with an Indian laboratory, the synthesis of 5-allyluridine and 5-allyl-2'-deoxyuridine was studied.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Developing dedicated methods and tools for safe use and processing of key chemicals in biorefining

International audienceThe emergence of biorefining, as the key concept of the future biobased economy is announced as the ultimate concept in many concerned industrial R&D roadmaps. Therefore, this paper proposes an insight of some safety related issues, as often underscored part of sustainability evaluation. From recent and still on-going research performed by the authors focusing on the appraisal of materials and process hazards in the context of biorefining, a brief review of recent achievements obtained by the authors in terms of the development of appropriate methods and tools aiming at promoting safety management in the related facilities are given. Both material and process driven safety issues are dealt with in the examples reported. Perspective on future related work in relation with the topic is brought in conclusion

Catalyse dans l'eau en présence de cyclodextrine native ou modifiée (Application au couplage croisé de type Suzuki)

Depuis quelques années, les acteurs du secteur de la chimie se sont donnés pour mission prioritaire de concevoir des produits et des procédés chimiques plus respectueux de l environnement afin de répondre aux préoccupations environnementales. Ainsi, les douze principes du concept de la chimie verte sont nés. L un de ces principes est de substituer, lors des synthèses, les solvants organiques, généralement toxiques, par des solvants plus éco-compatibles comme l eau et d un point de vue plus général, la catalyse joue un rôle majeur dans cette politique de chimie verte puisqu elle permet de réduire la consommation d énergie, de diminuer la quantité des réactifs utilisés ainsi que les procédés de séparation par augmentation de la sélectivité. Cependant, la faible solubilité dans l eau des substrats organiques ne permet pas l obtention de bons rendements. Afin de pallier ce problème, la catalyse par transfert de phase inverse peut être utilisée. La synthèse de nouveaux catalyseurs organométalliques solubles dans l eau a donc été envisagée. Ces catalyseurs seront dérivés de cyclodextrine et pourront également assurer le transport du substrat en phase aqueuse par reconnaissance supramoléculaire.For a few years, the priority task for actors of the chemical field has been the design of greener products and greener chemical processes to meet the environmental concerns. Thus, the twelve principles of the green chemistry were set. One of them is to substitute toxic organic solvents for more eco-compatible solvents, such as water, during chemical synthesis. More generally speaking, catalysis plays a significant role in this green chemistry policy as it enables to enhance energy saving, to reduce the quantity of the used compounds and to reduce as well the separation processes by increasing the selectivity. However, the low solubility of organic substrates in water prevents from having profitable yields. To tackle the issue, the catalysis by inverse phase transfer can be used. Therefore, the synthesis of new water soluble organometallic catalysts was considered. These catalysts will be derivates of cyclodextrin and will allow carrying the substrate in aqueous phase by supramolecular recognition.COMPIEGNE-BU (601592101) / SudocSudocFranceF

Chemo-Enzymatic Synthesis of Oligoglycerol Derivatives

A cleaner and greener method has been developed and used to synthesize 14 different functionalized oligomer derivatives of glycerol in moderate 29%–39% yields over three steps. After successive regioselective enzymatic acylation of the primary hydroxyl groups, etherification or esterification of the secondary hydroxyl groups and chemoselective enzymatic saponification, the target compounds can efficiently be used as versatile building blocks in organic and supramolecular chemistry