Synthesis of carbonated vegetable oils: Investigation of microwave effect in a pressurized continuous-flow recycle batch reactor

Tailor-Made Bio-Based Non-Isocyanate Polyurethanes (NIPUs)

Non-isocyanate polyurethanes (NIPUs) based on biobased polyamines and polycarbonates are a sustainable alternative to conventional polyurethanes (PU). This article discloses a novel method to control the crosslinking density of fully biobased isocyanate-free polyurethanes, synthesized from triglycerides carbonated previously in scCO₂ and different diamines, such as ethylenediamine (EDA), hexamethylenediamine (HMDA) and Priamine^TM-1075 (derived from a dimerized fatty acid). As capping substances, water or bioalcohols are used in such a way that the crosslinking density can be adjusted to suit the requirements of the intended application. An optimization of the NIPU synthesis procedure is firstly carried out, establishing the polymerization kinetics and proposing optimal conditions set for the synthesis of the NIPUs. Then, the influence of the partial blocking of the active polymerization sites of the carbonated soybean oil (CSBO), using monofunctional amines, on the physical properties of the NIPUS is explored. Finally, the synthesis of fully biobased NIPUs with a targeted crosslinking density is achieved using hybrid NIPUs, employing partially carbonated oil and H₂O or ethanol as blockers to achieve the desired physical properties in a very precise manner.

Yield and Selectivity Improvement in the Synthesis of Carbonated Linseed Oil by Catalytic Conversion of Carbon Dioxide

Carbonation of epoxidized linseed oil (CELO) containing five-membered cyclic carbonate (CC5) groups has been optimized to 95% by reacting epoxidized linseed oil (ELO) with carbon dioxide (CO2) and tetrabutylammonium bromide (TBAB) as catalysts. The effect of reaction variables (temperature, CO2 pressure, and catalyst concentration) on the reaction parameters (conversion, carbonation and selectivity) in an autoclave system was investigated. The reactions were monitored, and the products were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), carbon-13 nuclear magnetic resonance (13C-NMR) and proton nuclear magnetic resonance (1H-NMR) spectroscopies. The results showed that when carrying out the reaction at high temperature (from 90 °C to 120 °C) and CO2 pressure (60-120 psi), the reaction's conversion improves; however, the selectivity of the reaction decreases due to the promotion of side reactions. Regarding the catalyst, increasing the TBAB concentration from 2.0 to 5.0 w/w% favors selectivity. The presence of a secondary mechanism is based on the formation of a carboxylate ion, which was formed due to the interaction of CO2 with the catalyst and was demonstrated through 13C-NMR and FT-IR. The combination of these factors makes it possible to obtain the largest conversion (96%), carbonation (95%), and selectivity (99%) values reported until now, which are obtained at low temperature (90 °C), low pressure (60 psi) and high catalyst concentration (5.0% TBAB).

Plasma characterization of a microwave discharge ion source with mirror magnetic field configuration

Microwave coupling to plasma through cavity dependent resonant modes is one of the key aspects in a microwave discharge ion source (MDIS) for improving the ion beam qualities as well as plasma dynamics. Knowing these concerns, a MDIS is designed, fabricated, and developed at Institute for Plasma Research to produce high current and a low emittance ion beam for accelerator applications. The present manuscript reports the development of MDIS and the characterization results of the first plasma produced by launching a microwave (MW) of frequency 2.45 GHz. The plasma is characterized at a particular distance away from the ion extraction aperture, using three diagnostics tools such as a Langmuir Probe (LP), Optical Emission Spectroscopy (OES), and a microwave spectrum analyzer. The required mirror-B magnetic field is created by placing four high power ring magnets (each magnet pole strength is 1.38 T) around the cylindrical source chamber. All diagnostics measurements are performed under an operating pressure of range 2 × 10^-4-1 × 10^-3 mbar and the plasma absorbed power of 30-160 W. The measured cold electron temperature and density varies in the range of ∼1.5-11.8 eV and 5.6 × 10¹⁶ m^-3-6 × 10¹⁷ m^-3, respectively, within the source volume. The electron population has distinct hot and cold plasma temperature. The hot electron temperature changes from ∼20 to 70 eV within the above absorbed power range. The LP and OES measurements witnessed the density jumps from under-dense (∼7.3 × 10¹⁶ m^-3) to over-dense (∼2.9 × 10¹⁷ m^-3) for the change in absorbed power from 50 W to 80 W. This density jump is accompanied by the sideband generation around the cavity resonant mode (including the launched MW) frequencies which range from 238 kHz to 873 kHz and is recognized as ion waves from the dispersion relation. The ion temperature, estimated from these observed low frequency instabilities, changes from 0.095 to 1.25 eV. The influences of these instabilities on beam emittance growth are of paramount importance in future studies.