Montserrat Fortuny

Analysis of organic compounds of water-in-crude oil emulsions separated by microwave heating using comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry

In this work the higher peak capacity and resolution of comprehensive two-dimensional gas chromatography (GCxGC) has been successfully applied, for the first time, to tentatively identify several polar organic compounds of organic extracts of aqueous phases resulting from microwave demulsification process of water-in-crude oil emulsions. Results have shown that higher temperatures and longer exposure time to microwave irradiation produced water phases with a wider variety of polar organic compounds. The microwave process showed to be suitable for the extraction of several polar compounds classes of petroleum. The proposed microwave extraction method and GCxGC identification of polar compounds of petroleum samples are of practical interest for the petrochemical industry due to corrosion and related problems associated with these polar compounds in refinery equipments. The GCxGC/time-of-flight MS technique shows to be very important in the total separation of different classes of compounds and allows the identification of many compounds in these classes.

Distribuição de peso molecular em poliolefinas: contribuição ao estudo da bimodalidade e da desconvolução

The deconvolution of molecular weight distributions (MWD) may be useful to obtain information about the polymerization kinetics and properties of catalytic systems. However, deconvolution techniques are normally based on steady-state assumptions and very little has been reported about the use of non-stationary approaches for deconvolution of MWDs. In spite of that, polymerization reactions are often performed in batch or semi-batch modes. For this reason, dynamic solutions are proposed here for simple kinetic models and are then used for deconvolution of actual MWD data. Deconvolution results obtained with dynamic models are compared to deconvolution results obtained with the standard stationary Flory- Schulz distributions. For coordination polymerizations, results show that dynamic MWD models are able to describe expe- rimental data with fewer catalytic sites, which indicates that the proper interpretation of the reaction dynamics may be of fundamental importance for kinetic characterization. On the other hand, reaction dynamics induced by modification of chain transfer agent concentrations seems to play a minor role on the shape of the MWD in free-radical polymerizations