A bio-based alginate aerogel as an ionic liquid support for the efficient synthesis of cyclic carbonates from co2 and epoxides

Funding Information: This work was supported by Ministerio de Ciencia y Universidades (project RTI2018-097456-B-I00) and Funda??o para a Ci?ncia e Tecnologia FCT/MCTES (project PTDC/EQU-EPQ/31926/2017), UIDB/50006/2020 of the Associate Laboratory for Green Chemistry?LAQV and UIDB/00100/2020 of Centro de Qu?mica Estrutural. This work was also supported by a Short Term Scientific Mission of the CMST COST Action CM1206. A.B. Paninho is thankful to FCT for the doctoral fellowship PD/BD/52497/2014 and pos-doctoral fellowship PTDC/EQU-EPQ/31926/2017. The authors also thanks to the project ?SunStorage-Harvesting and storage of solar energy?, with reference POCI-01-0145-FEDER-016387, funded by European Regional Development Fund (ERDF), through COMPETE 2020-Operational Program. The NMR spectrometers at FCT NOVA are part of Rede Nacional de RMN (PTNMR), supported by FCT/MCTES through ROTEIRO/0031/2013? PINFRA/22161/2016 and co-financed by FEDER through COMPETE 2020, POCI, and PORL and FCT/MCTES through PIDDAC.In this work, the ionic liquid [Aliquat][Cl] was supported into alginate and silica aerogel matrices and applied as a catalyst in the cycloaddition reaction between CO2 and a bio-based epoxide (limonene oxide). The efficiency of the alginate aerogel system is much higher than that of the silica one. The method of wet impregnation was used for the impregnation of the aerogel with [Aliquat][Cl] and a zinc complex. The procedure originated a well-defined thin solvent film on the surface of support materials. Final materials were characterised by Fourier Transform Infrared Spectroscopy, N2 Adsorption–Desorption Analysis, X-ray diffraction, atomic absorption and Field Emission Scanning Microscopy. Several catalytic tests were performed in a high-pressure apparatus at 353.2 K and 4 MPa of CO2.publishersversionpublishe

Understanding bottom-up continuous hydrothermal synthesis of nanoparticles using empirical measurement and computational simulation

Continuous hydrothermal synthesis was highlighted in a recent review as an enabling technology for the production of nanoparticles. In recent years, it has been shown to be a suitable reaction medium for the synthesis of a wide range of nanomaterials. Many single and complex nanomaterials such as metals, metal oxides, doped oxides, carbonates, sulfides, hydroxides, phosphates, and metal organic frameworks can be formed using continuous hydrothermal synthesis techniques. This work presents a methodology to characterize continuous hydrothermal flow systems both experimentally and numerically, and to determine the scalability of a counter current supercritical water reactor for the large scale production (>1,000 T·year–1) of nanomaterials. Experiments were performed using a purpose-built continuous flow rig, featuring an injection loop on a metal salt feed line, which allowed the injection of a chromophoric tracer. At the system outlet, the tracer was detected using UV/Vis absorption, which could be used to measure the residence time distribution within the reactor volume. Computational fluid dynamics (CFD) calculations were also conducted using a modeled geometry to represent the experimental apparatus. The performance of the CFD model was tested against experimental data, verifying that the CFD model accurately predicted the nucleation and growth of the nanomaterials inside the reactor