Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Rodrigo O. M. A. de Souza x
Clear All Modify Search

In this perspective article, the use of continuous flow synthesis to prepare advanced pharmaceutical intermediates in developing economies is highlighted. Case studies are presented to suggest that cost effective local manufacture of life saving drugs, may potentially be implemented to facilitate better access to drugs to the underprivileged.

Open access
Journal of Flow Chemistry
Authors: Ivaldo Itabaiana Jr, Ivana C. R. Leal, Leandro S. M. Miranda and Rodrigo O. M. A. de Souza

Abstract

In this work, a three-step chemo enzymatic cascade reaction is reported for 1-monoacylglycerols from glycerol derived from biodiesel industry under continuous-flow conditions. Glycerol protection was performed using H2SO4/SiO2 (2.5% w/v) solid catalyst and acetone, generating 87% of solketal under 55 °C at 0.1 mL/min with glycerol–acetone ratio of 1.5:1. Coupled esterification between the formed solketal and stearic acid catalyzed by Rhizomucor miehei enzyme (RM IM) was able to maintain 90% of conversion until 1.5 M of substrate concentration at 0.1 mL/min flow rate and could be recycled up to 18 times. Final ketal cleavage was performed with the same H2SO4/SiO2 solid catalyst and the amount of water generated in the esterification reaction, whereas a flow rate of 0.2 mL/min was the best condition where the formation of 1-monoacylglycerol was maximized and byproducts were not detected.

Restricted access
Journal of Flow Chemistry
Authors: Druval S. De Sá, Bojan A. Marinkovic, Eric C. Romani, Tommaso Del Rosso, Rodrigo O. M. A. de Souza, Alessandro Massi and Omar Pandoli

We present prototyping of meso- and microfluidic photocatalytic devices, functionalized through incorporation of TiO2 nanoparticles in polydimethylsiloxane (PDMS), and comparison of their efficiencies for the degradation of rhodamine B (10−5 mol/L). The prototyping of the photocatalytic devices involves simple and low-cost procedures, which includes microchannels fabrication on PDMS, deposition and impregnation of TiO2 on PDMS, and, finally, plugging on the individual parts. For the microfluidic device with 13 μL internal volume, photocatalytic TiO2–PDMS composite was sealed by another PDMS component activated by O2 plasma (PDMS–TiO2–PDMS). For the mesofluidic device, a homemade polyetheretherketone (PEEK) flow cell with 800 μL internal volume was screwed on a steel support with a glass slide and the photocatalytic composite. The photocatalytic activities of the devices were evaluated using two different pumping flow systems: a peristaltic pump and a syringe pump, both at 0.05 mL/min under the action of 365 nm ultraviolet (UV) light. The characterization of TiO2–PDMS composite was performed by confocal Raman microscopy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The photocatalytic microreactor was the most efficient, showing high organic dye photodegradation (88.4% at 12.5 mW/cm2).

Restricted access
Journal of Flow Chemistry
Authors: Ingrid C. R. Costa, Ivaldo Itabaiana Jr., Marcella C. Flores, Ana Clara Lourenço, Selma G. F. Leite, Leandro S. de M. e Miranda, Ivana C. R. Leal and Rodrigo O. M. A. de Souza

Abstract

The use of glycerol derived from biodiesel industry is an important development to add value to this actual waste. Several products can be obtained from glycerol, but acetins are very interesting molecules with a wide range of applications in pharmaceutical, cosmetics, food, and fuel industry. Herein we report our results on biocatalyzed batch and continuous-flow process for valorization of glycerol derived from biodiesel industry towards acetin production. Excellent results can be obtained with different selectivities depending on the nature of glycerol used and reaction conditions being able to produce monoacetin, diacetin, or triacetin depending on the reaction condition.

Restricted access
Journal of Flow Chemistry
Authors: Raquel A. C. Leão, Raquel de O. Lopes, Marco A. de M. Bezerra, Mauro N. Muniz, Bruna B. Casanova, Simone C. B. Gnoatto, Grace Gosmann, Laszlo Kocsis, Rodrigo O.M.A. de Souza and Leandro S. de M. Miranda

The use of continuous-flow chemistry has shown to be an important tool in improving API manufacture. In the present paper, we report the use of continuous-flow reactors in the synthesis of the bicyclic side chain of antiretroviral Darunavir.

Restricted access