This thesis is an investigation into the development of amidine and guanidine based compounds to be employed as switchable surfactants. The surface activity of these molecules can be triggered by reaction with a benign gas, CO2. The ultimate application of these surfactants was to be used as emulsifying and demulsifying agents of crude oil and water emulsions. Synthesis and characterization of the following desired bases: N’-octyl-N,N-dimethylacetamidine (1), 2-octyl-2-imidazoline (2), 1-methyl-2-octyl-2-imidiazoline (3), N’-(4-heptylphenyl)-N,N-dimethylacetamidine (4), N’-(4-(octyloxy)phenyl)-N,N-dimethylacetamidine (5), N’-(4-(methyloxy)phenyl)-N,N-dimethylacetamidine (6), and N-octyl-N',N',N",N"-tetramethylguanidine (7) was carried out. Their solubility in water was quantified with NMR spectroscopy. All bases were reacted with CO2 and H2O to form bicarbonate salts, of which in situ characterization was achieved by IR and NMR spectroscopy. Percent conversion to the protonated forms at elevated temperatures was determined using NMR spectroscopy. A direct correlation between switchability and basicity was observed, as the strongest bases possessed the largest conversions to the protonated species, even at higher temperatures. The enthalpy of protonation was determined for each base through calorimetry experiments. These compounds were tested as demulsifying surfactants of crude oil and water emulsions. Demulsifying ability was determined to differ greatly with the head group structure of the various surfactants. / Thesis (Master, Chemistry) -- Queen's University, 2009-10-27 16:56:13.631

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When first received by a refinery, the crude oil usually contains some water, mineral salts, and sediments. The salt appears in different forms, most often times it is dissolved in the formation water that comes with the crude i.e. in brine form, but it could also be present as solid crystals, water-insoluble particles of corrosion products or scale and metal-organic compounds such as prophyrins and naphthenates. The amount of salt in the crude can vary typically between 5 to 200 PTB depending on the crude source, API, viscosity and other properties of the crude. For the following reasons, it is of utmost importance to reduce the amount of salt in the crude before processing the crude in the Crude Distillation Unit and consequently downstream processing units of a refinery. 1. Salt causes corrosion in the equipment. 2. Salt fouls inside the equipment. The fouling problem not only negatively impacts the heat transfer rates in the exchangers and furnace tubes but also affects the hydraulics of the system by increasing the pressure drops and hence requiring more pumping power to the system. Salt also plugs the fractionator trays and causes reduced mass transfer i.e. reduced separation efficiency and therefore need for increased re-boiler/condenser duties. 3. The salt in the crude usually has a source of metallic compounds, which could cause poisoning of catalyst in hydrotreating and other refinery units. Until a few years ago, salt concentrations as high as 10 PTB (1 PTB = 1 lb salt per 1000 bbl crude) was acceptable for desalted crude; However, most of the refineries have adopted more stringent measures for salt content and recent specs only allow 1 PTB in the desalted crude. This would require many existing refineries to improve their desalting units to achieve the tighter salt spec. This study will focus on optimizing the salt removal efficiency of a desalting unit which currently has an existing single-stage desalter. By adding a second stage desalter, the required salt spec in the desalted crude will be met. Also, focus will be on improving the heat integration of the desalting process, and optimization of the desalting temperature to achieve the best operating conditions in the plant after revamp.

Made available in DSpace on 2014-12-17T15:42:05Z (GMT). No. of bitstreams: 1 JoaoMApdf.pdf: 2174206 bytes, checksum: a1de24fc592da4515b2bf51d89278503 (MD5) Previous issue date: 2009-03-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The separation oil-water by the use of flotation process is characterized by the involvement between the liquid and gas phases. For the comprehension of this process, it s necessary to analyze the physical and chemical properties command float flotation, defining the nature and forces over the particles. The interface chemistry has an important role on the flotation technology once, by dispersion of a gas phase into a liquid mixture the particles desired get stuck into air bubbles, being conduced to a superficial layer where can be physically separated. Through the study of interface interaction involved in the system used for this work, was possible to apply the results in an mathematical model able to determine the probability of flotation using a different view related to petroleum emulsions such as oil-water. The terms of probability of flotation correlate the collision and addition between particles of oil and air bubbles, that as more collisions, better is the probability of flotation. The additional probability was analyzed by the isotherm of absorption from Freundlich, represents itself the add probability between air bubbles and oil particles. The mathematical scheme for float flotation involved the injected air flow, the size of bubbles and quantity for second, the volume of float cell, viscosity of environment and concentration of demulsifier. The results shown that the float agent developed by castor oil, pos pH variation, salt quantity, temperature, concentration and water-oil quantity, presented efficient extraction of oil from water, up to 95%, using concentrations around 11 ppm of demulsifier. The best results were compared to other commercial products, codified by ―W‖ and ―Z‖, being observed an equivalent demulsifier power between Agflot and commercial product ―W‖ and superior to commercial product ―Z‖ / A separa??o ?leo/?gua pelo processo de flota??o ? caracterizada pelo envolvimento entre as fases l?quida e gasosa. Para a compreens?o desse processo, ? necess?rio estudar as propriedades f?sicas e qu?micas que governam a flota??o, estabelecendo a natureza e as for?as entre as part?culas. A qu?mica de interfaces desempenha um papel importante na tecnologia de flota??o, onde, por dispers?o de uma fase gasosa em uma mistura na fase l?quida, as part?culas a serem flotadas prendem-se ?s bolhas de ar e s?o conduzidas at? a camada superficial da solu??o, onde s?o separadas fisicamente. Atrav?s do estudo das intera??es interfaciais envolvidas, foi poss?vel aplicar seus resultados em uma equa??o que determina a probabilidade de flota??o por uma nova ?tica relacionada ?s emuls?es de petr?leo do tipo ?leo/?gua. Os termos da probabilidade de flota??o correlacionam os fen?menos de colis?o e de ades?o entre as part?culas de ?leo e as bolhas de ar. Na probabilidade de colis?o observa-se que quanto maior o n?mero de colis?es maior a probabilidade de flota??o. A probabilidade de ades?o foi analisada atrav?s da isoterma de adsor??o de Freundlich, que representa a probabilidade de ades?o entre as bolhas de ar e as part?culas de ?leo. A modelagem matem?tica para a flota??o envolveu o fluxo de ar injetado, o tamanho das bolhas de ar, a quantidade de bolhas por segundo, o volume da c?lula de flota??o, a viscosidade e a concentra??o do desemulsificante. Os resultados mostraram que o agente de flota??o desenvolvido a partir do ?leo de mamona, ap?s a varia??o do pH, salinidade, temperatura, concentra??o de desemulsificante e teor de ?leo/?gua, apresentou uma efici?ncia de remo??o de ?leo em ?gua acima dos 95%, usando uma concentra??o em torno de 11 ppm de desemulsificante. Os melhores resultados foram comparados com outros produtos comerciais, codificados por ―W‖ e ―Z‖, sendo observado um poder desemulsificante equivalente entre o Agflot e o produto comercial ―W‖ e superior ao produto comercial ‖Z‖