Ana V.M. Nunes

Solubility of coenzyme Q10 in supercritical carbon dioxide

Abstract The equilibrium solubility of coenzyme Q10 (CoQ10) in supercritical carbon dioxide (scCO2) was measured by a static analytical method in the pressure range from 9 to 26 MPa, at temperatures of 305, 313 and 323 K. The cosolvent effect of ethanol in the solubility of the bioactive compound in scCO2 has been investigated, at 15 MPa and 313 K. A preliminary study of the viability of extracting CoQ10 with scCO2 has been investigated at 15 MPa and 313 K, using the content of commercial pharmaceutical capsules as the solid matrix feed. The solubility data results were correlated by use of the empirical density-based Chrastil model.

Dense CO2 as a Solute, Co-Solute or Co-Solvent in Particle Formation Processes: A Review

The application of dense gases in particle formation processes has attracted great attention due to documented advantages over conventional technologies. In particular, the use of dense CO2 in the process has been subject of many works and explored in a variety of different techniques. This article presents a review of the current available techniques in use in particle formation processes, focusing exclusively on those employing dense CO2 as a solute, co-solute or co-solvent during the process, such as PGSS (Particles from gas-saturated solutions®), CPF (Concentrated Powder Form®), CPCSP (Continuous Powder Coating Spraying Process), CAN-BD (Carbon dioxide Assisted Nebulization with a Bubble Dryer®), SEA (Supercritical Enhanced Atomization), SAA (Supercritical Fluid-Assisted Atomization), PGSS-Drying and DELOS (Depressurization of an Expanded Liquid Organic Solution). Special emphasis is given to modifications introduced in the different techniques, as well as the limitations that have been overcome.

MnII and CuII complexes with arylhydrazones of active methylene compounds as effective heterogeneous catalysts for solvent- and additive-free microwave-assisted peroxidative oxidation of alcohols

A one-pot template reaction of sodium 2-(2-(dicyanomethylene)hydrazinyl)benzenesulfonate (NaHL1) with water and manganese(II) acetate tetrahydrate led to the mononuclear complex [Mn(H2O)6](HL1a)2·4H2O (1), where (HL1a)− = 2-(SO3−)C6H4(NH)NC(CN) (CONH2) is the carboxamide species derived from nucleophilic attack of water on a cyano group of (HL1)−. The copper tetramer [Cu4(H2O)10(1κN:κ2O:κO,2κN:κO-L2)2]·2H2O (2) was obtained from reaction of Cu(NO3)2·2.5H2O with sodium 5-(2-(4,4-dimethyl-2,6-dioxocyclohexylidene)hydrazinyl)-4-hydroxybenzene-1,3-disulfonate (Na2H2L2). Both complexes were characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. They exhibit a high catalytic activity for the solvent- and additive-free microwave (MW) assisted oxidation of primary and secondary alcohols with tert-butylhydroperoxide, leading to yields of the oxidized products up to 85.5% and TOFs up to 1.90 × 103 h−1 after 1 h under low power (5–10 W) MW irradiation. Moreover, the heterogeneous catalysts are easily recovered and reused, at least for three consecutive cycles, maintaining 89% of the initial activity and a high selectivity.

Biocompatible locust bean gum mesoporous matrices prepared by ionic liquids and a scCO2 sustainable system

Locust bean gum (LBG) is a natural polymer that belongs to the increasingly attractive biodegradable polymers derived from natural sources. This polymer possesses a number of appealing features such as non-toxicity that confer it a high potential for the use in fields such as pharmacy and food industries. In this work, three methylimidazolium-based ionic liquids (ILs) were used as alternative media in the preparation of biocompatible LBG gel matrices. The process consists of dissolving the biomaterial in a selected IL followed by a multi-step solvent exchange using a mixture of water and ethanol. The final gel (internal surface areas ranging from 60 to 180 m2 g−1) is then dried using a semi-continuous high pressure CO2 extraction process. To the best of our knowledge this is the first time that LBG mesoporous gel matrices are reported using this efficient sustainable method.

Team-Based Learning in Chemistry Courses with Laboratory Sessions

The implementation of Team-Based Learning (TBL, http://www.teambasedlearning.org) in one-semester undergraduate courses of chemistry offered to first year students is reported. TBL is an active learning instructional strategy heavily relying on small group interaction. Teaching lab classes in a TBL context presented a specific challenge, as decisions were required about their role in the global framework and the possibility of incorporating lab activities as “teamwork”. The design of lab sessions as TBL team application activities is here also illustrated, both for a course of General Chemistry and a course of Organic Chemistry. TBLxa0 dramatically improved students class attendance and participation. Its implementation has provided a unique opportunity for the pedagogical development of teaching staff. A moderate number of students reported discomfort with TBL: the requirement of individual preparation before classes and the impact of team participation in the final grade is indeed a new ground for most students, often perceived as a troubling deviation from the common social paradigm of the learning process. The role of the instructor as a facilitator of individual and team work, and the clear explanation of the method are thus of utmost relevance.

Solubility of Bioactive, Inorganic and Polymeric Solids in Ionic Liquids — Experimental and Prediction Perspectives

This work was supported by Fundacao para a Ciencia e a Tecnologia through projects (PEstC/LA0006/2013, PTDC/CTM/103664/2008, EXPL/QEQ ERQ/2243/2013) one contract under Investigador FCT (L.C. Branco); two Postdoctoral fellowships (G.V.S.M. Carrera - SFRH/BPD/72095/2010 and A. V. M. Nunes - SFRH/BPD/74994/2010) and one doctoral fellowship (M. E.Zakrzewska SFRH/BD/74929/2010).

Ionic Liquids Gelation with Polymeric Materials: The Ion Jelly Approach

Nuno M.T. Lourenco1, Ana V.M. Nunes2, Catarina M.M. Duarte3,4 and Pedro Vidinha2 1IBB/CEBQ Departamento de Bioengenharia, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Avenida Rovisco Pais, Lisboa, 2Requimte/CQFB, Departamento de Quimica, Faculdade de Ciencias e Tecnologia Universidade Nova de Lisboa, Campus de Caparica, Caparica, 3Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Avenida da Republica, Oeiras, 4Instituto de Biologia Experimental e Tecnologica, Apartado 12, Oeiras, Portugal