Productionof poly(L-CO-D,L LacticAcid) porous fibers by electrospinning

The production of porous scaffolds has been widely investigated by the scientific community due to its suitability for tissue engineering. Among techniques that allow the fabrication of porous materials, electrospinning is appealing for being robust and versatile. This research investigated the pore formation in poly (L-co-D,L lactic acid) fibers obtained by conventional electrospinning and the influence of chloroform as a single solvent on fiber morphology. Random and highly porous fibers with a mean diameter of 2.373 ± 0.564 µm were collected. Chloroform affects the fiber morphology, mainly for its fast evaporation and low density of charges. The solvent on the surface evaporates quickly, and the low stretch of the jet does not help the polymer to reorganize over the length of the fiber, forming pores. In conclusion, the low dielectric constant and boiling point of chloroform induce pores formation along the PLDLA fibers.

Development of a robust algorithm to compute reactive azeotropes

In this paper, a novel approach for establishing the route for process intensification through the application of two developed softwares to characterize reactive mixtures is presented. A robust algorithm was developed to build up reactive phase diagrams and to predict the existence and the location of reactive azeotropes. The proposed algorithm does not depend on initial estimates and is able to compute all reactive azeotropes present in the mixture. It also allows verifying if there are no azeotropes, which are the major troubles in this kind of programming. An additional software was developed in order to calculate reactive residue curve maps. Results obtained with the developed program were compared with-the. published in the literature for several mixtures, showing the efficiency and robustness of the developed softwares.23339540

PRODUCTION OF MONOGLYCERIDES AND DIGLYCERIDES THROUGH LIPASE-CATALYZED GLYCEROLYSIS AND MOLECULAR DISTILLATION.

PRODUCTION OF MONOGLYCERIDES AND DIGLYCERIDES THROUGH LIPASE-CATALYZED GLYCEROLYSIS AND MOLECULAR DISTILLATION. Monoacilglycerides and diacilglycerides are produced through lipase-catalyzed glycerolysis of soybean oil using Candida antarctica B in a solvent-free system. The reaction was carried Out at a glycerol to triacylglycerol molar ratio of 8:1 with 2% of lipase. Acylglycerides, free fatty acids (FFA) and glycerol produced were separated employing the molecular distillation process. Starting from a product of enzymatic reaction 25.06% of triacylglycerols, 46.63% of diacylglycerides. 21.72% of monoacylglycerides, 5.38% of FFA and 1.21% of glycerol and after consecutively distillations. monoacylglycerides with 80% of purity was obtained and also oil with 54% of diacylglycerides to be used in human dietary.3261539154

Anhydrous ethanol production by extractive distillation: A solvent case study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Production of anhydrous ethanol in large scale has been made by extractive distillation using conventional solvents like ethylene-glycol. In the present paper, extractive distillation process is studied to obtain pure ethanol using ethylene-glycol and tetra ethylene-glycol as solvents. Residue curve maps are used to analyse the proposed distillation processes in interpreting mixture behaviours and feasibility of distillation columns. The industrial process is simulated at steady state from residue curve map analysis. Simulation results for the ethanol/water mixture using ethylene-glycol, the conventional solvent, and tetra ethylene-glycol, an alternative solvent, are presented. These results showed that the process using tetraethylene-glycol is reliable, although it requires more energy than the process with ethylene-glycol. However, ethylene-glycol has a considerable toxicity level while tetra ethylene-glycol is non-toxic. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.8816773Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [571683/19975 + 141893/2002-8

Comparison of two different strategies for tocopherols enrichment using a molecular distillation process

The objective of this study is to compare two different strategies for enriching tocopherols in soybean oil deodorizer distillate (SODD) using a molecular distillation process. The first strategy is to submit crude SODD to a sequence of molecular distillations using different temperatures without any preparation of the raw material. The second strategy is to modify chemically the raw material and submit it to a sequence of distillations. In SODD chemical modification, acylglycerol species are converted into free fatty acids (FFAs) and glycerol through a saponification reaction at 65 degrees C followed by an acidulation step. Crude and chemically modified SODD were submitted to five stages of molecular distillation to evaluate and compare the performance of both sequences of distillations. It was observed that the enrichment of tocopherols was 4.1 and 5.8 times higher than the original feed concentration for crude and chemically modified SODD, respectively.45275375

Short-Path-Distillation Process of Lemongrass Essential Oil: Physicochemical Characterization and Assessment Quality of the Distillate and the Residue Products

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Short-path distillation (SPD), a special high-tech thermal separation technique operating at high vacuum, was used in order to increase the citral concentration in lemongrass essential oil, without adding any extra components to the system, causing minimal thermal impact and reaching high quality for the essential oil extracted at the distillate stream. Experiments were carried out using a centrifugal molecular distillation unit with an evaporator temperature (EVT) from 60 to 120 degrees C and a feed flow rate (Q) from 1.5 to 4.5 mL . min(-1). Experimental protocols for oil and fat analysis were used to characterize the materials extracted. Results (obtained using GC-MS) showed that bSPD was successful in the separation and purification of essential oil. High-quality essential oil was confirmed because of citral concentration increases from 19.816 mg(citral) . mL(-1) (initial sample) to 40.963 mg(citral) . mL(-1) (at 120 degrees C and 4.5 mL . min(-1)), reaching a concentration of the bioactive compound (citral) in the distillate stream of 2.1 times the concentration in the original sample. The density, dynamic viscosity, and free fatty acids were 0.901 g . cm(-3), 2.069 mPa.s(-1), and 1.26 wt % (oleic acid), respectively, satisfying the oil quality criterion and avoiding thermal degradation.501381858194Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Development of a Predictive Model for Polymer/Solvent Diffusion Coefficient Calculations

A new calculation procedure for free-volume parameters is considered in this work by using viscosity prediction methods and the Levenberg-Marquardt calculation scheme. All parameters used in the Vrentas-Duda free-volume theory can be estimated from pure component properties. The prediction results are compared with experimental data for some polymer/solvent systems. The diffusion coefficient calculated by Vrentas-Duda theory can be used in the modeling of membrane separation processes. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3544-3-551, 200811063544355

Application of plate and component efficiency correlations in homogeneous azeotropic distillation processes

In this work, plate and component efficiency correlations have been applied and their performances have been investigated to predict the behavior of extractive distillation columns (homogeneous azeotropic distillation processes). These correlations were developed based on physical and thermal characteristics of the system, as well as on mass and heat transfer mechanisms. The simulation results obtained with the efficiency correlations have been compared with those calculated using the nonequilibrium stage model and also with the experimental data of a pilot-scale extractive distillation column. Very good agreement was obtained. Therefore, it can be concluded that the efficiency correlations are reliable and applicable to extractive distillation processes. The use of these correlations allows the calculations of distillation behavior to be conducted more precisely and with a lower computational burden.45165755576

Development of a mathematical model for studying bioethanol-water separation using hydrophilic polyetherimide membrane

An essentially predictive mathematical model was developed to simulate pervaporation process. The group contribution method UNIFAC was used for calculating the upstream activity coefficients. The diffusion coefficient in the membrane was predicted using free-volume theory. Free-volume parameters were determined with viscosity and temperature data, and the binary interaction solvent-polymer parameter was calculated by a group-contribution lattice-fluid equation of state (GCLF-EOS). A simulator named PERVAP was developed applying the mathematical model. Pervaporation process was simulated for separating bioethanol-water through polyetherimide membrane. The simulated results were validated using experimental data of bioethanol/water separation through polyetherimide membrane. The model presented a satisfactory performance compared to experimental data. Related to the simulation of the studied separation, a 99% molar enriched bioethanol stream was obtained with a recovery of 94%. (c) 2007 Wiley Periodicals, Inc.10742256226

Monoglyceride and Diglyceride Production Through Lipase-Catalyzed Glycerolysis and Molecular Distillation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Distilled glycerides are obtained through distillation of the system mono-diglycerides which is produced from the esterification reaction between a triglyceride with glycerol. In this work, monoglycerides (MG) and diglycerides (DG) are produced through lipase-catalyzed glycerolysis of soybean oil using Candida antarctica B in a solvent-free system. To separate the products of the reaction in order to obtain essentially MG and an oil of DG, it is necessary to use a suitable process in order to preserve the stability of the components and to keep the products free of inappropriate solvents. So, after 24 h of enzymatic reaction, the mixture of acylglycerols and fatty acids was distilled into a centrifugal molecular distiller, since it provides a free solvent and lower temperature environment to increase the desired product concentration. Starting from a material with 25.06% of triglycerides (TG), 46.63% of DG, 21.72% of MG, 5.38% of free fatty acids (FFA), and 1.21% of glycerol, the MG purity in the distillate stream was 80% at evaporator temperature (TE) equal to 250 C and feed flow rate (Q) equal to 10.0 mL/min. At these conditions, the MG recovery was 35%. The material collected in the residue stream presented DG-enriched oil with TG unhydrolyzed, residual MG, and low acidity (29.83% of TG, 53.20% of DG, 15.64% of MG, and 1.33% of FFA), which is suitable to replace TG oil in the human diet.160718791887Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP