Gonçalo V.S.M. Carrera

Estimation of melting points of pyridinium bromide ionic liquids with decision trees and neural networks

Regression trees were built with an initial pool of 1085 molecular descriptors calculated by DRAGON software for 126 pyridinium bromides, to predict the melting point. A single tree was derived with 9 nodes distributed over 5 levels in less than 2 min showing very good correlation between the estimated and experimental values (R2 = 0.933, RMS = 12.61 °C). A number n of new trees were grown sequentially, without the descriptors selected by previous trees, and combination of predictions from the n trees (ensemble of trees) resulted in higher accuracy. A 3-fold cross-validation with the optimum number of trees (n = 4) yielded an R2 value of 0.822. A counterpropagation neural network was trained with the variables selected by the first tree, and reasonable results were achieved (R2 = 0.748). In a test set of 9 new pyridinium bromides, all the low melting point cases were successfully identified.

Reversible systems based on CO2, amino-acids and organic superbases

A group of amino-acids from a chiral pool in combination with two organic superbases (DBU or TMG) and CO2 was used to prepare carbamate-based ionic liquids and molten salts. The compounds obtained were characterized by 1H NMR, 13C NMR, FTIR, solubility profiles in reference solvents and DSC thermal analysis, including their decomposition temperature evaluation, which permitted us to check the stability/reversibility of the carbamate based salts. Its possible to tune the temperature of CO2 release according to the superbase tested as cation and the characteristics of the side chains of the amino-acids. Moreover, it was possible to solubilize a considerable variety of these carbamate functionalized amino-acids in conventional solvents.

Physico-Chemical Properties of Task-Specific Ionic Liquids

Luis C. Branco1, Goncalo V.S.M. Carrera1, Joao Aires-de-Sousa1, Ignacio Lopez Martin2, Raquel Frade3 and Carlos A.M. Afonso3 1REQUIMTE, Departamento de Quimica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, 2829-516 Caparica 2Departamento de Quimica Organica, Universidad de Extremadura, Caceres E-10071, 3CQFM, Centro de Quimica-Fisica Molecular, IN Institute of Nanosciences and Nanotechnology, Instituto Superior Tecnico,1049-001 Lisboa, 1,3Portugal 2Spain

Tetramethylguanidine-based gels and colloids of cellulose

Novel and stable gels of cellulose were produced. These gels are prepared at room temperature by combination of cellulose and tetramethylguanidine (TMG) in different ratios (1:1, 1:2, 1:3 in equivalents of alcohol groups of cellulose per number of molecules of TMG). Detailed NMR, SEM, rheological and XRD studies of these gels were carried out. The concentration of cellulose in the gel, temperature, frequency of oscillation and shear rate were used as variables in order to understand the fundamentals and optimize operational conditions, considering their possible use as matrices for CO2 capture. Cellulose recovery from a specific gel was performed using ethanol as precipitating agent, leading to a lower crystallinity, which permits to consider this polymer in further studies associated to physical/chemical modification of cellulose.

Bio-inspired Systems for Carbon Dioxide Capture, Sequestration and Utilization

This chapter reviews the study and development of biological, enzymatic and biomolecular systems for carbon dioxide capture and further sequestration or even utilization. Regardless of the interest on the use of the captured CO2 as C1 synthon on the manufacture of added-value compounds, there is a tremendous unbalance between the requirements of the contemporary society (leading to a massive production of carbon dioxide) and the framework of commercialization of the products from CO2 utilization. In this context, viable options are storage as a solid in the form of calcium or magnesium carbonate and conversion into other energetic frameworks. In addition, it is important to highlight that the conventional energy resources are progressively being replaced by renewable resources. While the change in energetic paradigm is not accomplished, systems that capture and convert carbon dioxide are highly sought. To this end, bio-inspired systems will be presented, starting from the use of compounds from the chiral pool, such as amino acids, saccharides and related bio-polymers, involved in the physical and chemical capture, sequestration and/or utilization of CO2. Additionally, enzymatic systems are presented in the context of sequestration of CO2 in the form of solid carbonates or even utilization of this C1 synthon in the preparation of fuels and commodity chemicals. Carbonic anhydrase is by far the most studied enzyme, as it catalyses the inter-conversion between CO2 and hydrogencarbonate in an effective mode. The biological option comprises the utilization of methanogens, acetogens and other organisms leading to the formation of added-value compounds. Most of the described systems are based on microbial electro-synthesis model and microbial carboncapture cell prototypes.

Highly water soluble room temperature superionic liquids of APIs

Herein a straightforward approach for the enhancement of the water solubility of common antibiotic and NSAID active pharmaceutical ingredients (APIs) is presented. The APIs are converted into ionic liquids (API-ILs) and molten salts by combination with the organic superbases TMG, DBU and DBN. The prepared superionic liquids were characterized by 1H and 13C NMR as well as FTIR spectroscopy and elemental analysis. Most products are amorphous non-polymorphic room temperature ionic liquids with very high solubility in water, which may enhance the bioavailability of the API-ILs in comparison with the parent drugs.

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).

Capture agents, conversion mechanisms, biotransformations and biomimetics: general discussion

Eryk Remiezowicz, Jeroen Spooren, Elizabeth Bay, Alexander Cowan, Ian Ingram, Pedro Abrantes, Manuel Nunes da Ponte, Michael North, Jonathan Albo, Peter Styring, Michael Priestnall, Katie Lamb, Michele Aresta, Elsje Alessandra Quadrelli, Richard Heyn, André Bardow, William Webb, Renata Silva, Carlos Alonso-Moreno, Csaba Janaky, Geoffrey Maitland, Seetharaman Vaidyanathan, Gonçalo V. S. M. Carrera, Daniel Reed, Karolien Vanbroekhoven, Cafer Tayyar Yavuz, Deepak Pant and Nathan Hollingsworth