Murcia Almagro, María Dolores

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Murcia Almagro, María Dolores

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Murcia Almagro, María Dolores

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Universidad de Murcia. Departamento de Ingeniería Química

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Open Access
A review of guerbet alcohols and their esters: synthesis, applications, and future perspectives
(MDPI, 2025-11-14) Montiel Morte, María Claudia; Ortega Requena, Salvadora; Gómez Gómez, María; Murcia Almagro, María Dolores; Máximo, María Fuensanta; Bastida Rodríguez, Josefa; Ingeniería Química; Facultad de Química
Guerbet alcohol esters are compounds with specific properties that make them particularly suitable for use as cosmetic ingredients, plasticizers, or biolubricants. Guerbet alcohols are used for their synthesis. These are primary alcohols with beta branching and a lower melting point than their linear counterparts. Due to the branching, the products are liquid at lower temperatures, have good volatility, and exhibit better color and oxidation stability. This paper presents a systematic literature review on the synthesis and applications of Guerbet alcohol esters. Finally, emphasis is placed on the future of these synthesis processes, which could be based on the use of biocatalysts, thus promoting the application of new environmentally friendly procedures.
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Continuous tank reactors in series: an improved alternative in the removal of phenolic compounds with immobilized peroxidase
(Taylor and Francis Group, Taylor and Francis, 2012-01-24) Gómez Gómez, Elisa; Máximo, María Fuensanta; Montiel Morte, María Claudia; Gómez Gómez, María; Murcia Almagro, María Dolores; Ortega Requena, Salvadora; Ingeniería Química; Facultad de Química
Immobilized derivatives of soybean peroxidase, covalently bound to a glass support, were used in a continuous stirred tank reactor in series, in order to study the removal of two phenolic compounds: phenol and 4-chlorophenol. The use of two reactors in series, rather than one continuous tank, improved the removal efficiencies of phenol and 4-chlorophenol. The distribution of different amounts of enzyme between the two tanks showed that the relative distributions influenced the removal efficiency reached and the degree of the enzyme deactivation. The highest removal percentages were reached at the outlet of the second tank for a distribution of 50% of the enzyme in each tank. However, with a distribution of 75% in the first tank and 25% in the second, the elimination percentage in the second tank was slightly lower than in the previous case, and the effects of deactivation of the enzyme in the first tank were less pronounced. In all the distributions assayed it was observed that the first tank acts as a filter for the second one, which receives a feed with a smaller load of phenolic compounds, thus diminishing enzyme deactivation in the second tank.
Open Access
Guerbet alcohols, ideal substrates for the sustainable production of branched esters
(MDPI, 2025-11-11) Montiel Morte, María Claudia; Máximo, María Fuensanta; Gómez Gómez, María; Murcia Almagro, María Dolores; Ortega Requena, Salvadora; Bastida Rodríguez, Josefa; Ingeniería Química; Facultad de Química
Saturated and branched high molecular weight organic esters are highly valued as emollients in the cosmetic industry due to their superior properties. Their saturated character provides resistance to oxidation and rancidity. Additionally, their branched structure endows them with low melting temperatures, enabling them to remain liquid over a broad temperature range. These esters can be obtained from branched alcohols, branched fatty acids or both, using chemical or enzymatic processes. Among branched alcohols, Guerbet alcohols stand out. Due to their characteristic properties as branched, saturated alcohols with superior oxidative stability and extremely low volatility, they are proposed as excellent substrates for the enzymatic synthesis of these compounds. This study represents the first investigation into the biocatalytic synthesis of three specific esters: those formed between 2-octyl-1-dodecanol (C20 Guerbet alcohol) and the fatty acids myristic (MA), palmitic (PA), and stearic acid (SA). To achieve this, an environmentally sustainable biocatalytic process was developed. The synthesis involves a solvent-free esterification catalyzed by the commercial immobilized lipase, Lipozyme® 435, conducted within a vertically stirred, thermostated batch tank reactor. Optimal conditions for lipase concentration and temperature were established, and the sustainability of the process was successfully quantified using various “green metrics”.
Open Access
Comparative analysis of kinetic parameters of sustainable branched esters obtained from lauric acid
(American Chemical Society, 2026-02-03) Gómez Gómez, María; Murcia Almagro, María Dolores; Gómez Gómez, Elisa; Hidalgo Montesinos, Asunción María; Máximo, María Fuensanta; Montiel Morte, María Claudia; Ingeniería Química; Facultad de Química
A comparison between four esterification reaction systems to obtain new sustainable branched esters using Novozym 435 as a biocatalyst, the same acid (lauric acid), and four alcohols with different chain lengths and side chains (2-hexyl-1-decanol, 2-ethyl-1-hexanol, 2-butyl-1-octanol, and 3,7-dimethyl-1-octanol) has been carried out. The parameters of the reaction have been optimized in 0.5 g of biocatalyst, temperature of 70 °C, and the stoichiometric molar ratio (1:1). Under these conditions, conversion values of >90% are obtained in the four reactions. Using a kinetic model developed by the authors and based on a Bisubstrate Ping-Pong mechanism, where internal diffusional limitations are considered, the kinetic parameters for each reaction system were determined and the theoretical conversion values closely matched the experimental results, validating the model for this wide range of substrates. Attending at the conversion values obtained, where both the reaction rate and transport rate are considered, the esterification with 3,7-dimethyl-1-octanol leads to the highest average rate, followed by the reactions with 2-ethyl-1-hexanol, 2-butyl-1-octanol, and, finally, 2-hexyl-1-decanol. In the first two systems, the ones with alcohols of shorter side chain and chain length, respectively, the kcat values are very high (49.526 and 90.13 Mh–1 g–1, respectively) and so is the reaction rate, leading to a high average rate. However, when 3,7-dimethyl-1-octanol is used, the conversion values decrease at long reaction times, due to the high volatility of this alcohol. In the reaction system with 2-butyl-1-octanol, there is mixed control of the reaction and transport stages with higher values of the effectiveness factor (above 0.5 in most cases). Finally, in the reaction with 2-hexyl-1-decanol, the alcohol with the longest chain length and side chain, and the highest molecular weight and viscosity, internal diffusional limitations are very high (with low values of the effectiveness factors as expected, around 0.2 for all conditions tested), and the reaction rate is quite low as well, which explains the low average rates obtained. The obtained branched esters are of interest in the biolubricant sector, and the kinetic parameters calculated in this study can be useful to allow simulation, further optimization, and scale up of the esterification process.
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A diffusion-reaction kinetic model for the removal of aqueous 4-chlorophenol with immobilized peroxidase
(Elsevier, 2010-11-13) Gómez Carrasco, J.L.; Gómez Gómez, E.; Máximo, María Fuensanta; Gómez Gómez, María; Murcia Almagro, María Dolores; Ortega Requena, Salvadora; Ingeniería Química; Facultad de Química
A diffusion-reaction kinetic model is presented for the kinetic analysis of the removal process of phenolic compounds using hydrogen peroxide and immobilized peroxidase. The good results obtained in the fitting of the experimental data to the model confirm its validity, in the experimental range considered, as well as the one of the extended version of the Dunford mechanism proposed in a previous paper. The phenomenon of enzyme deactivation and/or sequestration by the precipitated olygomers/polymers, which has been widely described in the literature, is here modeled as the growth of a polymeric film over the external surface and inside the pores of the catalytic particles that contain the enzyme, thus determining the appearance of diffusional limitations and an increasing loss of activity. The deactivation phenomena, interpreted and modeled in terms of the effectiveness factor, are included in the kinetic model. To confirm the validity of the model, several series of experiments were carried out in a discontinuous tank reactor. Some of these experimental series were used to obtain the values of the kinetic parameters by numerical calculation and using an error minimization algorithm. Since the model reproduces the behavior of the system for the series of experiments not used for the determination of the parameters, it can be affirmed that the model is suitable for the kinetic analysis of the system under study.
Open Access
Biocatalytic synthesis of polymeric esters used as emulsifiers
(Croatian Society of Chemical Engineers, 2019) Ortega Requena, Salvadora; Serrano-Arnaldos, M.; Montiel Morte, María Claudia; Máximo, María Fuensanta; Bastida Rodríguez, Josefa; Murcia Almagro, María Dolores; Ingeniería Química
Polyglycerol polyricinoleate (PGPR) is a polymeric ester widely used as emulsifier in the food industry. In this work, PGPR biocatalytic synthesis was carried out in a onestep solvent-free enzymatic process using lipase CALB immobilized in Lewatit® Monoplus MP 64 by adsorption. The optimal immobilization conditions were determined: initial enzyme concentration of 13 mg of Lowry protein per mL phosphate buffer pH 7, and ricinoleic acid as a support activator. An immobilized derivative with 35.93 ± 4.90 mg of Lowry protein per g of dry support was obtained. It was used as a catalyst for PGPR production in open air and vacuum batch reactors, and the results obtained showed that only when the reaction equilibrium was shifted towards ester production by means of water removal, the PGPR produced fulfilled the European legislation (acid value ≤ 6 mg of KOH per g of product).
Open Access
Modelling and experimental checking of the influence of substrate concentration on the first order kinetic constant in photo-processes
(Elsevier, 2016-09-19) Gómez Gómez, María; Murcia Almagro, María Dolores; Gómez Gómez, Elisa; Ortega Requena, Salvadora; Sánchez, A.; Thaikovskaya, O.; Briantceva, N.; Ingeniería Química; Facultades de la UMU::Facultad de Química
Most photoprocesses follow a pseudo first order kinetic law and, commonly, the kinetic parameter depends on the initial concentration of the substrate. In this work, a kinetic model, which explains this dependence on the substrate concentration and on the other operational variables, has been developed. In the model, mass transfer of substrate from the bulk solution to the wall of the photoreactor was assumed as the step determining the rate of the process. To check the model, methylene blue (MB) has been used as model substrate and photodegradation experiments have been carried out in an exciplex KrCl flow-through photoreactor, It was observed that the methylene blue conversion improved with a decrease in its initial concentration, in good agreement with the model. Also, by fitting the experimental data to the model, high correlation coefficients and a high degree of agreement between experimental and calculated conversion was obtained, which validates the model.
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Polyamide nanofiltration membranes to remove aniline in aqueous solutions
(Taylor and Francis Group, Taylor and Francis, 2013-12-09) Hidalgo Montesinos, Asunción María; León, G.; Gómez Gómez, María; Murcia Almagro, María Dolores; Bernal, M.D.; Ortega Requena, Salvadora; Ingeniería Química; Facultad de Química
Aniline is commonly used in a number of industrial processes. It is known to be a harmful and persistent pollutant and its presence in wastewater requires treatment before disposal. In this paper, the effectiveness of nanofiltration (NF) to remove aniline from aqueous solutions is studied in a flat membrane test module using two thin-layer composite membranes of polyamide (NF97 and NF99HF). The influence of different operational variables (applied pressure, feed concentration and pH) on the removal of aniline from synthetic aqueous solutions was analysed. The experimental NF results are compared with results previously obtained by reverse osmosis. Based on this comparative study, the effective order for aniline rejection is: HR98PP>NF97>DESAL3B>SEPA-MS05>NF99HF.
Open Access
Influence of the operating conditions on lipase-catalysed synthesis of ricinoleic acid estolides in solvent-free systems
(Elsevier, 2008-12-25) Bódalo, A.; Bastida Rodríguez, Josefa; Máximo, María Fuensanta; Montiel Morte, María Claudia; Murcia Almagro, María Dolores; Ortega Requena, Salvadora; Ingeniería Química
In this work, the synthesis of ricinoleic acid estolides, also named polyricinoleic acid (PR), in two different solvent-free reaction systems, catalysed by immobilised Candida rugosa lipase is described. First, the esterification was performed in an open air jacketed batch reactor and the influence of amount of enzyme, temperature and initial water content was tested. The best results were obtained when 5 g of soaked immobilised derivative was used as biocatalyst, and the reaction was carried out at 40 °C. It was observed that environmental relative humidity plays an important role in the enzymatic synthesis of ricinoleic acid estolides and, given that this parameter takes on a wide range of values depending on the season, it is considered the main cause of the poor reproducibility achieved in the open air reactor. To solve this problem, the ricinoleic acid estolides were synthesised under controlled atmosphere in a vacuum reactor with dry air intake. The optimum drying time of 7 h was selected. In these conditions, PR with an acid value of 57.5 mg KOH/g was synthesised in 48 h of reaction and the results were entirely reproducible.
Open Access
Advanced oxidation of PET-derived monomers using excimer radiation and hydrogen peroxide: kinetic and operational insights
(MDPI, 2026-01-29) Gómez Gómez, María; Montiel Morte, María Claudia; Gómez Gómez, Elisa; Hidalgo Montesinos, Asunción María; Máximo, María Fuensanta; Murcia Almagro, María Dolores; Ingeniería Química; Facultades de la UMU::Facultad de Química
Growing environmental concern over plastic pollution has increased the need to address the persistence of PET-derived monomers, such as bis(2-hydroxyethyl) terephthalate (BHET) and terephthalic acid (TPA). This work examines the use of excimer radiation lamps combined with hydrogen peroxide (H2O2) to enhance advanced oxidation processes (AOPs) for their degradation. This approach stands out for its high selectivity, absence of mercury, and lower production of toxic byproducts. Experimental tests assessed how different operational factors affect pollutant degradation, such as the initial pollutant concentration (50–200 mg/L), the reaction volume (125–500 mL), and the H2O2:monomer mass ratio (0:1–6:1 for BHET and 0:1–4:1 for TPA). For BHET, the best results occurred with a 5:1 mass ratio, while TPA degraded optimally with a 3:1 ratio, with a 250 mL reaction volume and a 100 mg/L initial concentration for both compounds. Under these conditions, total degradation of the initial monomers was achieved in around 30 and 80 min for BHET and TPA, respectively, and at the end of the reaction, COD decreased by 46% and 32% relative to their initial values. In both cases, hydrogen peroxide was crucial since UV radiation alone led to much lower degradation efficiency. These results emphasize the need to optimize operational conditions for greater efficiency and establish a starting point for future use of excimer technology in the treatment of wastewater contaminated with PET and its derivatives. Additionally, the degradation data closely matched a pseudo-first-order kinetic model (R2 ≈ 1), confirming its reliability for predictive analysis, which is of high importance for the simulation and optimization of the process.