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Since 5-(hydroxymethyl)furfural (HMF) has been labelled as the “sleeping giant” of the bio-based platform-chemical realm, numerous investigations have been devoted to the exploitation of this versatile molecule and its endless chemical transformations into novel monomers for producing bio-based polymers. However, beyond 2,5-furandicarboxylic acid (2,5-FDCA), little attention has been devoted to key aspects that deserve being addressed before bringing forward other HMF-derivatives into the bio-based plastic market, i.e., procedures, scaling-up of the syntheses, products’ purification, physical-thermal properties, and above all green metrics (sustainability/greenness of procedures). This critical review focuses on the most investigated derivatives of HMF beyond 2,5-FDCA, assessing their exploitation as monomers for bio-based polymers. HMF-derived compounds have been classified according to their functionalities, i.e., aldehyde-, diol-, polyol-, amine-, acid-, ester-, carbonate-, acrylate-, and epoxy-based monomers. The related synthetic approaches are discussed, evaluating the sustainability of the procedures reported so far, based on green metrics such as the environmental factor (E-factor) and the process mass intensity (PMI). For each family of HMF derivatives, their use as monomers for the synthesis of bio-based polymers has been addressed, taking into consideration the efficiency of the polymerisation reactions, the physical-chemical and thermal properties of the resulting bio-based polymers, as well as their biodegradability if applicable. The overall picture that emerges is that much has been achieved for the synthesis of furan monomers; however, many obstacles still need to be overcome prior to massively introducing these compounds into the bio-based plastic market. Hopefully, the data reported in this review will shed light on the goals achieved so far, and on some critical issues that must still be tackled in the short- or medium-term for a more sustainable

Lipase B from Candida antarctica (CALB) is able to catalyze C–C bond formation. After immobilization onto a hydrophobic PS-DVB support, the activity increases when compared to that of the soluble or tan – the commercially available Novozyme 435 (being up to 6 fold more active). Our results show that although this activity is not related to the catalytic group, the promiscuous activity of CALB may be tuned via immobilization. In addition, we have show that the secondary structure of both immobilized enzymes is quite different, using FT-ATR-IR spectroscopy.

Highly ordered rod-like polymeric monoliths with large-pores have been successfully synthesized using ionic liquids (ILs) IL-1 (1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf2]) and IL-2 (1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [OMIM][NTf2]) as alternative porogenic solvents. The presence of ILs can not only promote the formation of a highly ordered macroporous structure, control the morphology of the polymer and control the chemical composition of surfaces for monoliths prepared from DVB. In this regard, post-functionalization of the monoliths can be easily achieved using the functional monomers introduced in the polymerization process or the unreacted vinyl groups present in the polymeric matrix. This control has allowed the preparation of monolithic Supported Ionic Liquid-like Phases (m-SILLPs) with excellent morphological properties. These m-SILLPs have been studied as supports for large biomolecules. Bioadsorption studies show that the adsorbed amount of protein reaches values as high as 150–200 mg of protein per gram of support.

An exhaustive experimental study based on X-ray diffraction analysis, NMR, FTIR-ATR (attenuated total reflection), and Raman spectroscopy as well as theoretical calculations is reported in order to understand how the non-covalent intermolecular contacts are fundamental to explain structure–property relationships and allowing us to correlate a basic macroscopic property (i.e., the melting point, Tm) with the structural variables of a family of enantiopure 1,4-dialkyl-1,2,4-triazolium salts. The effect of different structural vectors such as the ring size, the spatial disposition of the substituent, the substitution on the oxygen atom, the nature of the anion, or the N4 alkylation of the triazole on the intermolecular interactions of these chiral salts of a well-defined 3D structure is reported. The non-covalent intermolecular contacts mainly implicating the triazolium H3 proton are fundamental to explain structure–property relationships and, therefore, the physical properties of these new chiral salts, rather than simple anion–cation interactions. Overall, our findings highlight the importance of the specific supramolecular interactions for the understanding of the physical properties of triazolium salts and ionic liquids.

The physico-chemical properties of polymers with ionic-liquid-like moieties covalently bound to their surfaces (SILLPs) have been studied by thermal and spectroscopic techniques, as well as by direct impedance and dielectric measurements, and compared to those of the corresponding bulk ionic liquids. The effective transfer of properties from ionic liquids in solution to the supported species has thereby been demonstrated. The effects of the chemical nature of these tunable ¿solid solvents¿ on their macroscopic swelling and microwave heating, as well as the stabilities and activities of different catalytic moieties immobilized on the SILLPs, have been studied. Finally, the experimental effect observed in microwave heating can be directly correlated with the values of tand derived from dielectric measurements.

The physico-chemical properties of polymers with ionic-liquid-like moieties covalently bound to their surfaces (SILLPs) have been studied by thermal and spectroscopic techniques, as well as by direct impedance and dielectric measurements, and compared to those of the corresponding bulk ionic liquids. The effective transfer of properties from ionic liquids in solution to the supported species has thereby been demonstrated. The effects of the chemical nature of these tunable ¿solid solvents¿ on their macroscopic swelling and microwave heating, as well as the stabilities and activities of different catalytic moieties immobilized on the SILLPs, have been studied. Finally, the experimental effect observed in microwave heating can be directly correlated with the values of tand derived from dielectric measurements.

A novel family of triazolium salt enantiomers has been efficiently synthesized by combining chemical and biocatalytic methods. The stereoselective action shown by hydrolytic enzymes led to the design of simple and general chemoenzymatic routes in which tunable vectors, such as ring size, substituent stereochemistry, oxygen substitution, anion nature, or N4-triazole alkylating chain, were considered to produce 30 enantiopure triazolium salts in very high overall yields. Finally, selected triazolium salts were tested as phase-transfer catalysts in the asymmetric Michael addition of diethyl malonate to trans-chalcone to rationalize their activity and stereopreference. Low to complete conversion values were achieved in the formation of the Michael addition adduct, which mainly gave low levels of stereoselectivity depending on the different structural patterns considered in this systematic study.

Supported ionic liquid-like phases were prepared by anchoring imidazolium moieties onto highly crosslinked poly(p-chloromethylstyrene-co-divinylbenzene) monolithic matrixes. The influence of the chemical nature of the anions on the response of supported ionic liquid-like phases to electrical perturbation fields was studied by impedance spectroscopy over wide ranges of frequency and temperature. The exchange of the chloride anions (Cl-) by bis(trifluormethanesulfonyl)amide anions (NTf2 -) greatly affects the psychic-chemical properties of the resulting material. The equivalent circuit that describes the impedance response of the SILLP materials used in this study to electrical perturbation fields is a resistance independent of frequency in series with a parallel Rp-CPE circuit. At high frequencies the CPE has the behavior of a capacitance. The ionic conductivity of the system increases 2 orders of magnitude by exchanging Cl- anions for NTf2 -. Despite the apparent high cross-linking degree of the supporter, the systems having imidazolium units with Cl- and NTf2 - as counterions apparently exhibit a glass-liquid transition in the vicinity of 343 K (70 °C) and 313 K (40 °C), respectively. Dipolar relaxations and conductive process are discussed in terms of chain mobility

This paper reports a simple and robust modular synthetic strategy that leads to a large variety of configurationally and structurally diverse imidazole-based chiral ionic liquids (CILs) by lipase-catalyzed resolution. The intimate microscopic interactions of the supramolecular ionic network of these imidazolium chiral salts at the molecular level are investigated both spectroscopically (NMR, FT-IR-ATR) and theoretically, and a topological analysis of the experimental electron densities obtained by X-ray diffraction of single crystals is performed. Our results support the key role played by the relative configuration of the -OR group on the hydrogen-bonding pattern and its strong influence on the final physical properties of the imidazolium salt. We also obtained a reasonable correlation between the observed melting point and the non-covalent interactions. The spectroscopic data and the topological analysis reflect the key role played by hydrogen bonds between the OH and imidazolium C2H groups in both cation–anion and cation–cation interactions, with the presence of an OH group leading to an additional inter-cation interaction. This interaction significantly affects the properties of stereoisomeric salts. Even more interestingly, we also studied the effect of the chirality by comparing enantiopure CILs with their racemic mixtures and found that, with the exception of trans-Cy6-OH-Im-Bn-Br, the melting points of the racemic mixtures are higher than those of the corresponding enantiomerically pure forms. For stereoisomeric examples, we have successfully explained the differences in melting temperatures in light of the corresponding structural data. Chirality should therefore be taken into account as a highly attractive design vector in the preparation of ILs with specifically desired properties.

Monolithic polymers functionalised with BOX-Cu moieties can be applied for the cyclopropanation reaction under batch and flow conditions using either conventional or supercritical solvents.

A chiral pyridine-bis(oxazoline) ligand, functionalized with a vinyl group in the pyridine ring, can be polymerized with styrene and divinylbenzene to obtain supported chiral ligands. As proof of the usefulness of this supported ligands, the corresponding ruthenium complexes are catalysts for the cyclopropanation reaction of styrene with ethyl diazoacetate with up to 85% ee.

Bis(oxazolines) are easily immobilized by functionalization of the central methylene bridge with polymerizable groups and subsequent polymerization. Polymers are transformed into copper catalysts active in the cyclopropanation of styrene with ethyl diazoacetate. The results are similar or even better than those obtained with the similar homogeneous systems, and the catalysts can be easily recovered and reused. The substitution in the methylene bridge leads to a slight reduction in the enantioselectivity and an unexpected cis-preference.

Bis(oxazoline)–copper complexes can be immobilized by cationic exchange or a covalent bond to the support. In the first strategy the co-ordination properties of the solid counterion influence the results obtained, as is the case in the homogeneous phase. However, the solid counterions also lead to steric interactions with the chiral ligand and so the bis(oxazoline) behaves differently depending on its substituents and the nature of the anionic support. The best overall results are obtained with nanocomposite Nafion–silica as a support and the bis(oxazoline) with phenyl groups. In the second strategy the covalent bond between the ligand and an organic support can be achieved using a preformed polymer or by synthesis of the support using a functionalized chiral ligand. The best results are obtained with the latter system but the copolymerization conditions are critical for the activity and enantioselectivity of the catalyst.