Influence of the operating conditions on lipase-catalysed synthesis of ricinoleic acid estolides in solvent-free systems

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 57.5mgKOH/g was synthesised in 48 h of reaction and the results were entirely reproducible

Eliminación de Cu2+ de efluentes acuosos

Se presenta un estudio de eliminacibn de Cuw por adsorcidn sobre pasta de celulosa al sulfato. Se han obtenido las isotermas de equilibrio a la temperatura de 30'0" C y pH 4,5 y 6, respectivamente. En los tres casos las curvas se ajustan a funciones del tipo Koble-Corrigan, con n = 2. Para los mismos pH y concentraciones de 1, 3, 5, 7 y 10 ppm de Cua* se .han trazado los hentes de adsorci6n. Finalmente, siguiendo el rtatamiento de Michaels se han calculado, a partir de dichos frentes, las .distintas características del proceso: LUB, V. E, G,N ~ Gy ,H m,r espectivamente

Simulación de un reactor-cambiador PARTE II

Como aplicación al tratamiento sobre simulación de un reactorcambiador expuesto en la PARTE I, se realiza a continuación un ejemplo de diseño para un sistema de reacciones simultáneas altamente exotérmicas, empleando agua como agente de enfriamiento. En base al tratamiento teórico expuesto en la PARTE I, como aplicación y comprobación de cuanto allí quedó discutido, se ha realizado el diseño de un reactor catalítico para la producción de óxido de etileno, diseño en el que han participado, durante el curso 1978-79, un grupo de alumnos (*) de la asignatura de Economía y Proyectos, cuya docencia imparte el Departamento de Química Técnica

Nanofiltration membranes to reduce phenol concentration in wastewater

©. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Accepted Manuscript version of a Published Work that appeared in final form in [Desalination]. To access the final edited and published work see [https://www.sciencedirect.com/science/article/pii/S0011916409003889?via%3Dihub].Physical, chemical and biological methods have been described to remove phenolic compounds. None of them are the definitively solution of the environmental problem caused by the discharge of this pollutants. Hybrid processes that combine pressure driven membrane processes with adsorption processes have been developed. Our research group studied the removal of phenol with three reverse osmosis membranes, the rejection percentages obtained were very low (40%), besides this parameter increases when the operating pressure decreases. For this reason, in this paper, a study of phenol removal from aqueous solutions by nanofiltration using different experimental conditions (feed phenol concentration, pressure and pH) and different membranes (NF-97, NF-99 and DSS-HR98PP) is carried out. Water permeability coefficients were also obtained. The best results are obtained with DSS-HR98PP membrane increasing the rejection percentage up to 80%

ENZYMATIC BIOSYNTHESIS OF RICINOLEIC ACID ESTOLIDES

Candida rugosa lipase has been shown to have sufficient activity to catalyse the enzymatic synthesis of ricinoleic acid estolides in a batch reactor. The water requirements of the reactor change during the reaction: at the beginning of the process a minimum amount of water is necessary but, later, the reaction mixture must be dried out to obtain an estolide with a high degree of condensation. The influence on the reaction rate of variables, such as water content, enzyme concentration and mixing devices, was established and optimised. Using an initial water content of 144000 ppm and a lipase concentration of 13.33 mgE/g ricin, and maintaining the temperature at 40°C by mean of hot air circulation and using a three-bladed propeller stirrer as mixing device, an estolide of ricinoleic acid with an acid number of 65 was obtained in 48 hours

SCREENING AND SELECTION OF LIPASES FOR THE ENZYMATIC PRODUCTION OF POLYGLYCEROL POLYRICINOLEATE

We have demonstrated, for the first time, that polyglylcerol polyricinoleate (PGPR) can be synthesised using lipases as biocatalyst with very good results. Of the twenty one lipases screened for their ability to catalyse PGPR production from a mixture of polyricinoleic acid and polyglycerol-3, only twelve lipases were able to catalyse the reaction. All of them were from microbial sources (bacteria and fungi) and were 1, 3-specific or "random" lipases. The selection procedure was based not only on the enzymatic activity but also on economic criteria. Lipases from Mucor javanicus, Rhizopus arrhizus and Rhizopus oryzae were finally chosen, and all three enzymes were successfully immobilized by adsorption onto an anion exchange resin where they showed their suitability to catalyse the synthesis of PGPR. This represents a promising starting point for developing an industrial process for the green production of polyglycerol polyricinoleate