Browsing by Author "Nieto-Mestre, Javier"
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Item Semicontinuous copolymerization of 80/20 wt % [2-(acryloyloxy)ethyl] trimethyl ammonium chloride/acrylamide in an inverse microemulsion at high comonomer concentrations(2009-12-01) Ochoa-Gómez, José R.; Escudero-Sanz, Francisco J.; Sasia, Pedro M.; Río, Francisca; Nieto-Mestre, Javier; Torrecilla, Jesús; Katime, Issa A.; Tecnalia Research & Innovation; VALORIZACIÓN DE RESIDUOS; SGThe semicontinuous inverse microemulsion copolymerization of 80/20 wt % [2-(acryloyloxy)ethyl]trimethylammonium chloride/acrylamide in an isoparaffin solvent at high comonomer concentrations (30-42 wt %) was studied with a mixture of nonionic surfactants (Crill 43 and Softanol 90) as the emulsifier and sodium metabisulfite as the initiator. The influence of the total comonomer concentration (TCC), emulsifier concentration (EC), hydrophilic-lipophilic balance (HLB), isopropyl alcohol (chaintransfer agent) concentration (IPC), and crosslinking agent concentration (CAC) on the weight-average molar mass (M w), absolute viscosity (BV), and viscometric structuring index (VSI) of the obtained copolymers was analyzed. Mw and BV increased with TCC and HLB and decreased with EC. At the higher TCC, Mw decreased with IPC; meanwhile, at the lower TCC, Mw increased with IPC above 0.5 wt %. VSI increased with TCC, HLB, and IPC and decreased with EC. VSI increased dramatically with CAC, whereas BV showed a peak at the CAC of 10 ppm. In the absence of both chain-transfer and crosslinking agents, Mw increased linearly with VSI, and this suggests that linear copolymers of very high M w values cannot be obtained by inverse microemulsion copolymerization, at least for high TCCs. The results are explained in terms of both the collapsed state of the copolymer chains inside the latex particles and changes in the interface structure and composition.Item Synthesis of glycerol carbonate from 3-chloro-1,2-propanediol and carbon dioxide using triethylamine as both solvent and CO2 fixation-activation agent(2011-11-15) Ochoa-Gómez, José R.; Gómez-Jiménez-Aberasturi, Olga; Ramírez-López, Camilo A.; Nieto-Mestre, Javier; Maestro-Madurga, Belén; Belsué, Mikel; Tecnalia Research & Innovation; BIOECONOMÍA Y CO2; VALORIZACIÓN DE RESIDUOSThe synthesis of glycerol carbonate from 3-chloro-1,2-propanediol, a glycerol derivative easily obtained by reacting glycerol with HCl, and carbon dioxide using triethylamine as both solvent and CO2 fixation and activation agent is reported. The influence on conversions and yields of triethylamine/3-chloro-1,2-propanediol molar ratio, temperature, CO2 pressure and reaction time has been studied. A 3-chloro-1,2-propanediol conversion of 100% and a glycerol carbonate yield of 90% are obtained at 100°C, using a triethylamine/3-chloro-1,2-propanediol molar ratio of 1.5, a carbon dioxide pressure of 25bar and 60min. Glycerol was the only byproduct detected in 4-6% yields independently of experimental conditions. Above 100°C, glycerol carbonate yield decreases dramatically due to glycerol carbonate polymerization resulting in a polyglycerol mixture. The yield of glycerol carbonate is strongly and negatively influenced by the presence of water. A reaction mechanism is proposed in which the first step is the formation of a zwitterionic adduct between triethylamine and CO2 which reacts with 3-chloro-1,2-propanediol leading to an intermediate which evolves towards glycerol carbonate either directly or through the glycidol intermediate.