This work presents new phase equilibrium data of {CO 2 + 2-ethyl-1-hexanol} and {CO 2 + 2-methyl-2-propanol} systems with or without glycerol. The static synthetic method using a variable-volume view cell was utilized to measure vapor− liquid equilibrium saturation points at temperatures from 343 K to 393 K and at pressures up to 20 MPa. The phase transition pressure measurements were carried out by injecting a known amount of carbon dioxide into a mixture of [0.0087 glycerol + 0.9913 (2-ethyl-1-hexanol or 2-methyl-2-propanol)]. This amount of added glycerol did not significantly affect vapor−liquid transition pressures, compared to binary systems without glycerol. The Peng−Robinson equation of state was used to correlate the experimental phase equilibrium data.

Hard segment hydrogen bonding interactions in a particular polyurethane segmented copolymer have been analysed through a viscometric approach to determine the behaviour of polyurethane solutions with different solvent compositions. Analysis of log ηspversus log c[η] master curves (solely comprising dilute and semidilute regimes) showed that these systems could be differentiated by the slope of the first part of the curve (dilute regime), the characteristic reduced concentration c*[η], and the slope of the second part of the curve (semidilute regime), differences which were related to a possible occurrence of polymer aggregates. Experiments with solutions in the concentrated regime, at different temperatures, were used to relate non‐Newtonian behaviour to hydrogen bonding. © 2001 Society of Chemical Industry

Growing environmental concerns, along with the search for renewable energies that emit less CO2, put biodiesel in a favorable position. Biodiesel is commonly produced by the transesterification reaction between vegetable oils and methanol or ethanol, in the presence of a catalyst. With government incentives for biodiesel production in Brazil, there was an exaggerated increase in their production and hence the concern about the disposal of surplus glycerol. Therefore research is being developed with respect to the use of the surplus of glycerol. In this context, emerged as the alternative use of fuel additives, from glycerin to contribute to the development of new applications for innovative and environmentally-friendly processes. The bibliographic review presented here starts with describing the different glycerol production processes, characterization and analysis methods. Next, Glycerol-based processing methods are described, evaluating the main reaction parameters that interfere in process optimization.

Abstract. Biofuels, such as biodiesel has obtained more and more relevance in the national scenario, because of the current concerns related to the burning of fossil fuels, besides of laws in force that determine the increase of biodiesel blend in common diesel each year. Thus, in this study a comparative exergetic analysis was carried out between the biodiesel production from soybean oil via basic homogeneous catalysis, case 1, where sodium hydroxide (NaOH) was used as a catalyst, and by means of supercritical alcohol, case 2, in which methanol was led to critical state. For that, two production plants were simulated in Aspen HYSYS ® V9 software accepting the same amount of main feedstock, in this case soybean oil. After the simulations, the exergetic efficiency of each process was calculated through to a global control volume (CV), having as result 94.01 and 93.50 % to the Case 1 and 2, respectively. These results confirm the feasibility of biodiesel production and the little exergetic difference was caused principally by the conditions of temperature and pressure that were imposed in the methanol supercritical case.

This work presents experimental data on liquid–liquid equilibrium (LLE) for the system 2-ethyl-1-hexanol + glycerin. Equilibrium data were obtained through “cloud point” method, at temperatures of 298.15 K, 313.15 K, 333.15 K, 368.15 K, 383.15 K, 403.15 K, and 433.1 K. For the experimental data, a UNIQUAC model was used to describe the phase’s equilibrium performance. Posteriorly, a phase split stability test was done to validate the parameters found in this model. The system presented “upper critical solution temperature” (UCST), and the parameters of the UNIQUAC model were satisfactorily adjusted (1.27% standard deviation). The stability phase test (phase split) proved the validation of the tested model.