- ItemOpen AccessUse of biobased crude glycerol, obtained biocatalytically, to obtain biofuel additives by catalytic acetalization of furfural using SAPO catalysts(Elsevier, 2022) Guerrero-Ruíz, Federico; Yara Varón, Edinson; González, María Dolores; Torres i Grifo, Mercè; Salagre, Pilar; Canela i Garayoa, Ramon; Cesteros, YolandaHigh-pure crude glycerol, obtained from the transesterification of coconut oil with ethanol using lipase enzyme- type as biocatalyst, has been used for the acetalization of furfural with several SAPO 5 and SAPO 34 catalysts. SAPOs were prepared using microwaves and conventional heating for comparison, and were characterized by X- ray diffraction, nitrogen physisorption, elemental analysis, thermogravimetry of adsorbed cyclohexylamine and scanning electron microscopy techniques. The use of microwaves allowed us the incorporation of slightly higher amounts of silicon into the aluminophosphate structure, and the preparation of the materials in much shorter preparation times, with the subsequent energy saving. Additionally, the SAPOs prepared with microwaves showed lower crystallinity but higher surface area than those prepared by conventional heating. Comparable catalytic results were obtained when these catalysts were tested for the acetalization of furfural with commercial or with the crude glycerol obtained by biocatalytic transesterification of coconut oil, leading to very high selectivity values to the desired mixture dioxane +dioxolane (93–100 %), which can be used as biofuel additives, for conversion values between 60 and 73 %, as determined by gas chromatography. This confirmed the high purity of the glycerol obtained by the biocatalytical process, as previously observed by 1H NMR. SAPO 34 cat-alysts showed higher conversion than SAPO 5 catalysts due to their higher amount of more accessible Brønsted acid sites, related to their structure. Interestingly, catalysts prepared with microwaves resulted in slightly higher conversion values than those prepared by conventional heating. This can be explained by the incorporation of higher amounts of silicon in the framework, probably due to the higher homogeneity of the microwaves heating, which results in a higher amount of protons, as confirmed by TGA of adsorbed cyclohexylamine, responsible for the catalysis. 1. Introduction Valorization strategies of wastes from agri-food processes must necessarily be intertwined with clean technological approaches and eco- industrial management within a sustainable biorefinery concept. Bio- refineries might integrate processes developing cascade approaches, which often require the application of biotechnological and chemical processes in order to obtain high-added value products. Glycerol (1, 2, 3-propanetriol) is obtained in significant amounts as by-product in a great variety of industrial processes, such as trans-esterification of triglycerides to produce fatty acid methyl esters, e.g. biodiesel (about 10% w/w) or through saponification processes . Although glycerol has many applications in cosmetics, pharmaceuticals and food products [2–3], it is necessary to develop new processes to transform this surplus into high-added value products [2,4–8]. For most of these applications, and independently of the origin (synthetic, animal or vegetable fat), crude glycerol should be refined to obtain glycerol with high purity degree [9,10]. Crude glycerol is initially produced in a raw form that contains water and other residues as im-purities depending on the production process. It is usually treated and refined by filtration, adding chemical additives, by fractioned distilla-tion in vacuum or using lower-energy intensive filtration by a series of ion exchanges in resins . Another alternative is to develop cleaner processes to obtain more pure glycerol, for example, by applying enzy-matic technologies.
- ItemOpen AccessIntroducing Lipophilicity to (Polyhydroxyalkyl) thiazolidine Carboxylic Acids Via Acylation(American Chemical Society, 2022) Novo Fernández, Olalla; Oliveros Gómez, Diego Fernando ; Balcells Fluvià, Mercè; Canela i Garayoa, Ramon; Méndez Arteaga, Jonh Jairo ; Eras i Joli, Jordihe therapeutic efficacy of bioactive compounds isrelated to their bioavailability. In turn, the bioavailability dependson the equilibrium between the hydrophilicity and the lipophilicity.2(R,S)-(Polyhydroxyalkyl)thiazolidine-4(R)carboxylicacids(TCAs), obtained from the condensation ofL-cysteine and analdose, have been recognized as nontoxic precursors of glutathionewith important preventive and therapeutic effects. The bioavail-ability of these compounds can be improved by enhancing theirlipophilicity. This can be achieved by the introduction of some acylgroups derived from fatty acids via esterification of the aldosehydroxyl groups. With this purpose four new compounds weresynthesized through a selective palmitoyl acylation ofD-(−)-ribose andD-(+)-glucose and subsequent condensation withL-cysteine.In addition, the log P of the new compounds was calculated as a measure of the lipophilicity, and in vitro 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) tests were performed as a measure of the antioxidant capability.
- ItemOpen AccessSustainable Synthesis of Omega-3 Fatty Acid Ethyl Esters from Monkfish Liver Oil(MDPI, 2021-01-13) Aguilera-Oviedo, Johanna; Yara Varón, Edinson; Torres i Grifo, Mercè; Canela i Garayoa, Ramon; Balcells Fluvià, MercèThe search for economic and sustainable sources of polyunsaturated fatty acids (PUFAs) within the framework of the circular economy is encouraged by their proven beneficial effects on health. The extraction of monkfish liver oil (MLO) for the synthesis of omega-3 ethyl esters was performed to evaluate two blending systems and four green solvents in this work. Moreover, the potential solubility of the MLO in green solvents was studied using the predictive simulation software COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS). The production of ethyl esters was performed by one or two-step reactions. Novozym 435, two resting cells (Aspergillus flavus and Rhizopus oryzae) obtained in our laboratory and a mix of them were used as biocatalysts in a solvent-free system. The yields for Novozym 435, R. oryzae and A. flavus in the one-step esterification were 63, 61 and 46%, respectively. The hydrolysis step in the two-step reaction led to 83, 88 and 93% of free fatty acids (FFA) for Novozym 435, R. oryzae and A. flavus, respectively. However, Novozym 435 showed the highest yield in the esterification step (85%), followed by R. oryzae (65%) and A. flavus (41%). Moreover, selectivity of polyunsaturated fatty acids of R. oryzae lipase was evidenced as it slightly esterified docosahexaenoic acid (DHA) in all the esterification reactions tested.
- ItemOpen AccessEffect of four novel bio-based DES (Deep Eutectic Solvents) on hardwood fractionation(MDPI, 2020) Torres, Paulo; Balcells Fluvià, Mercè; Cequier Manciñeiras, Enrique; Canela i Garayoa, RamonUsing the basic principle of construction between a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), four bio-based deep eutectic solvents (DESs) were prepared in a 1:2 molar ratio of HBA:HBD. 2,3-Dihydroxypropyl-1-triethylammonium chloride ([C9H22N+O2]Cl婨 ) was synthesized from raw glycerol and used as an HBA. Lactic acid, urea, pure glycerol, and ethylene glycol were selected as HBD. Attempts to prepare DESs, using citric acid and benzoic acid as HBDs, were unsuccessful. All these DESs were characterized using FTIR and NMR techniques. Besides, physicochemical parameters such as pH, viscosity, density, and melting point were determined. The behavior of these DES to fractionate olive pomace was studied. Lignin recovery yields spanned between 27% and 39% (w/w) of the available lignin in olive pomace. The best DES, in terms of lignin yield ([C9H22N+O2]Cl婨 -lactic acid), was selected to perform a scale-up lignin extraction using 40 g of olive pomace. Lignin recovery on the multigram scale was similar to the mg scale (38% w/w). Similarly, for the holocellulose-rich fractions, recovery yields were 34% and 45% for mg and multi-gram scale, respectively. Finally, this DES was used to fractionate four fruit pruning samples. These results show that our novel DESs are alternative approaches to the ionic liquid:triethylammonium hydrogen sulfate and the widely used DES: choline chloride:lactic acid (1:10 molar ratio) for biomass processing
- ItemOpen AccessPreparation and uses of chlorinated glycerol derivatives(MDPI, 2020-05-28) Canela Xandri, Anna; Balcells Fluvià, Mercè; Villorbina Noguera, Gemma; Christou, Paul; Canela i Garayoa, RamonCrude glycerol (C3H8O3) is a major by-product of biodiesel production from vegetable oils and animal fats. The increased biodiesel production in the last two decades has forced glycerol production up and prices down. However, crude glycerol from biodiesel production is not of adequate purity for industrial uses, including food, cosmetics and pharmaceuticals. The purification process of crude glycerol to reach the quality standards required by industry is expensive and dificult. Novel uses for crude glycerol can reduce the price of biodiesel and make it an economical alternative to diesel. Moreover, novel uses may improve environmental impact, since crude glycerol disposal is expensive and dificult. Glycerol is a versatile molecule with many potential applications in fermentation processes and synthetic chemistry. It serves as a glucose substitute in microbial growth media and as a precursor in the synthesis of a number of commercial intermediates or fine chemicals. Chlorinated derivatives of glycerol are an important class of such chemicals. The main focus of this review is the conversion of glycerol to chlorinated derivatives, such as epichlorohydrin and chlorohydrins, and their further use in the synthesis of additional downstream products. Downstream products include non-cyclic compounds with allyl, nitrile, azide and other functional groups, as well as oxazolidinones and triazoles, which are cyclic compounds derived from ephichlorohydrin and chlorohydrins. The polymers and ionic liquids, which use glycerol as an initial building block, are highlighted, as well.