Acid-Catalysed Conversion of Carbohydrates into Furan-Type Molecules in Zinc Chloride Hydrate

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Acid-catalysed conversion of biomass, specifically cellulose, holds promise to create value-added, renewable replacements for many petrochemical products. We investigated an unusual acid-catalysed transformation of cellulose and cellobiose in the biphasic solvent system zinc chloride hydrate (ionic liquid)/anisole. Here, furyl hydroxymethyl ketone and furfural are obtained as major products, which are valuable but less commonly formed in high yields in transformations of cellulosic substrates. We explored this chemistry in small-scale model reactions and applied the optimised methods to the conversion of cellulose in bench-scale processes. The optimum reaction system and preferred reaction conditions are defined to select for highly desirable furanoid products in the highest known yields (up to 46 %) directly from cellulose or cellobiose. The method avoids the use of added catalysts: the ionic solvent zinc chloride hydrate possesses the intrinsic acidity required for the hydrolysis and chemical transformation steps. The process involves inexpensive media for the catalytic conversion of cellulose into high-value products under mild processing conditions

A Systematic Study of Metal Triflates in Catalytic Transformations of Glucose in Water and Methanol: Identifying the Interplay of Brønsted and Lewis Acidity

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Invited for this month′s cover is the group of Prof. Bradley Williams at the University of Technology Sydney. The image depicts the manifold products that can be selected in transformations of glucose through manipulation of the Brønsted or Lewis acidity of the catalyst. The Full Paper itself is available at 10.1002/cssc.201900292

Acid-Catalyzed Conversion of Carbohydrates into Value-Added Small Molecules in Aqueous Media and Ionic Liquids

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Biomass is the only realistic major alternative source (to crude oil) of hydrocarbon substrates for the commercial synthesis of bulk and fine chemicals. Within biomass, terrestrial sources are the most accessible, and therein lignocellulosic materials are most abundant. Although lignin shows promise for the delivery of certain types of organic molecules, cellulose is a biopolymer with significant potential for conversion into high-volume and high-value chemicals. This review covers the acid-catalyzed conversion of lower value (poly)carbohydrates into valorized organic building-block chemicals (platform molecules). It focuses on those conversions performed in aqueous media or ionic liquids to provide the reader with a perspective on what can be considered a best case scenario, that is, that the overall process is as sustainable as possible

Charge-tagged polar phosphine ligands in Pd-catalysed reactions in aqueous and ionic media

© 2018 Elsevier Ltd A new range of polar imidazolium and phosphate-containing ligands was synthesised from readily available starting materials in high yielding multi-step transformations. These ligands were used to generate Pd catalysts for Suzuki and Heck C–C coupling reactions in organic and organic/aqueous media. The catalysts performed well in aqueous media in the Suzuki reaction and less well in the Heck reaction, related to substrate solubility in the aqueous media. When moving to ionic liquids, the Heck reaction dramatically improved, especially in media compatible with the polar catalysts and the non-polar reagents. In all cases, the catalysts were stable to the formation of Pd black, a form of degradation that frequently befalls Pd catalysts. The catalysts could be successfully recycled without loss of activity

Rac-[2-(Dicyclohexylphosphanyl)phenyl](phenyl)phosphinic diisopropylamide-borane hemihydrate

In the title compound, C30H48BNOP2·0.5H2O, the water molecule is disordered about an inversion centre. Both phosphorus atoms shows distortions in their tetrahedral environments with the cyclohexyl substituents disordered over two orientations in a 0.851 (3):0.149 (3) occupancy ratio. The crystal structure is assembled via O - H⋯O interactions between pairs of phosphininc amide molecules and water molecules, creating hydrogen-bonded dimers with graph-set R 2 4(8) along [001]. Weak C - H⋯O interactions are also observed

P,P-Bis[4-(dimethylamino)phenyl]-N,N-bis(propan-2-yl)phosphinic amide

The molecular structure of the title compound, C22H 34N3OP, adopts a distorted tetrahedral geometry at the P atom, with the most noticeable distortion being for the O - P - N angle [117.53 (10)°]. An effective cone angle of 187° was calculated for the compound. In the crystal, weak C - H⋯O interactions create infinite chains along [100], whereas C - H⋯π interactions propagating in [001] generate a herringbone motif

Linear and macrocyclic water soluble polyacylhydrazones and their utilisation in coatings

© 2018 Elsevier B.V. Water soluble polyacylhydrazones have been generated that contain a high proportion of renewable materials. The polyacylhydrazones were found to be present simultaneously as linear and macrocyclic species, the latter being favoured at higher concentrations and in certain combinations of levulinoyl ester/acyldihydrazide. Levulinoyl esters with multiple ketone reactive sites were targeted as building blocks for the backbone. Reaction of these species in aqueous media with commercially available acyldihydrazides afforded a series of high solids-content water soluble polyacylhydrazone solutions. Evaporation of the water from the solutions reproducibly generated films with differing and useful characteristics. One of the polyhydrazones was successfully formulated into two different types of resin bases of commercial coating systems, producing paint products with renewable content

4-(3-Azaniumylpropyl)morpholin-4-ium chloride hydrogen oxalate: An unusual example of a dication with different counter-anions

© 2014 International Union of Crystallography. The mixed organic-inorganic title salt, C7H18N2O2+·C2HO4-·Cl-, forms an assembly of ionic components which are stabilized through a series of hydrogen bonds and charge-assisted intermolecular interactions. The title assembly crystallizes in the monoclinic C2/c space group with Z = 8. The asymmetric unit consists of a 4-(3-azaniumylpropyl)morpholin-4-ium dication, a hydrogen oxalate counter-anion and an inorganic chloride counter-anion. The organic cations and anions are connected through a network of N - H⋯O, O - H⋯O and C - H⋯O hydrogen bonds, forming several intermolecular rings that can be described by the graph-set notations R33(13), R21(5), R12(5), R21(6), R23(6), R22(8) and R33(9). The 4-(3-azaniumylpropyl)morpholin-4-ium dications are interconnected through N - H⋯O hydrogen bonds, forming C(9) chains that run diagonally along the ab face. Furthermore, the hydrogen oxalate anions are interconnected via O - H⋯O hydrogen bonds, forming head-to-tail C(5) chains along the crystallographic b axis. The two types of chains are linked through additional N - H⋯O and O - H⋯O hydrogen bonds, and the hydrogen oxalate chains are sandwiched by the 4-(3-azaniumylpropyl)morpholin-4-ium chains, forming organic layers that are separated by the chloride anions. Finally, the layered three-dimensional structure is stabilized via intermolecular N - H⋯Cl and C - H⋯Cl interactions

Transition- and Lanthanide-Metal-Based Coordination Polymers Offer Efficient Methylene Blue Adsorption

This study presents a novel approach toward wastewater remediation via the synthesis of a series of coordination polymers that combine benzene-1,4-dicarboxylic acid, benzene-1,4-dihydroxamic acid, and 5-nitroisophthalic acid linkers with Cu, Cr, Ce, and La metal salts to target efficient methylene blue removal. Through a detailed characterization process using techniques like ¹H NMR, PXRD, FTIR, TGA, SEM-EDX, ICP-OES, and BET, the structural and surface properties of these CPs were optimized for stability and enhanced adsorption performance. Notably, the CPs exhibited rapid MB adsorption within 10 min and followed pseudo-second-order kinetics, indicating a chemisorption-driven process. This work advances the field by demonstrating that increased pH significantly improves adsorption capacity and that the Sips model best describes the heterogeneous adsorptive behavior, highlighting a mixed Langmuir–Freundlich mechanism. Furthermore, stability and reusability studies revealed minimal metal leaching in the best-performing CPs, addressing critical environmental concerns around long-term CP use. This integrated approach not only fills vital knowledge gaps in CP-based dye adsorption kinetics but also underscores the potential of these materials as sustainable, scalable, and effective solutions for real-world water treatment applications

Cu(II) complexes using acylhydrazones or cyclen for biocidal antifouling coatings

Copper and copper-based compounds have broad spectrum antimicrobial activity, but concerns about leaching into the environment and toxicity on non-target organisms is leading the use of copper-based coatings being restricted. Our objective was to develop coatings that used the biocidal activity of copper, but with low negative impacts by reducing its leaching into the environment. This study reports the synthesis and characterisation of copper coordinating ligands, their formulation into coatings and testing of their antibacterial activity. A polyacylhydrazone and a series of simple acylhydrazones were synthesised and coordinated to Cu(II), but were considered unsuitable due to either their poor water-solubility or high levels of copper leaching. In an alternative approach, copper was successfully chelated to the tetraazamacrocycle, cyclen, and used to synthesise Cu(II)-cyclen functionalised silica particles, which were successfully combined with commercial paint formulations. These functionalised products showed poor antibacterial activity when incorporated into epoxy coatings, probably due to the low copper content of the formulations. However, these ligands may have other applications, such as removal of heavy metals from contaminated effluent steams