Biodiesel is an alternative fuel, renewable, biodegradable and no toxic. The transterification of vegetable oils or animal fat with alcohol is the most usual manner of production of that fuel. The objectives of this study were to evaluate the process of production of biodiesel in pilot scale, and carry out the study of the variables that influence the process of etanolise of soybean oil, using a catalyst basic sodium hydroxide, in order to obtain the conditions operational leading to greater conversion to biodiesel and also assess the variables that influence the process of purification of fuel. The pilot plant consists of a glass reactor with a capacity of 3 L, provided with: Jersey movement of heated water and mechanical agitation. The experiments to study the production of biodiesel from soybeans have been conducted in accordance with the planning factor fragmented. Already the study of the same purification process was conducted in accordance with a schedule full factorial. The variables studied for the production process were: temperature of reaction (30-70 oC); concentration of catalyst (0,5-1,5%), time of reaction (0,5-2 hours); speed of agitation ( 150-350 rpm), and ethanol molar ratio: soybean oil (4:1-10:1). And these variables for the purification process were: temperature (30-70 ° C) and pH (2-5) of water washing. In the study of the production of biodiesel from soybean parameter of the evaluation was to conversion into biodiesel, determined by gas chromatography, using the chromatograph VARIAN, model CP-3800, and for studying the process of purification, the parameter of response was the amount of Water spent to counteract the biodiesel from soybean. At the end of the work was verified that the variables: molar ratio oil / alcohol, the reaction temperature and concentration of the catalyst has strong influence in the production of biodiesel. And as the temperature and pH of the water for washing exercise strong influence in the soybean biodiesel purification process. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O biodiesel e um combustivel alternativo, renovavel, biodegradavel e nao toxico. A transesterificacao dos oleos vegetais ou gordura animal com alcool e a forma mais usual de producao desse combustivel. Os objetivos desse trabalho foram avaliar o processo de producao do biodiesel em escala piloto, bem como, realizar o estudo das variaveis de processo que influenciam a etanolise do oleo de soja, utilizando o hidroxido de sodio como catalisador basico, de forma a se obter as condicoes operacionais que levam a uma maior conversao em biodiesel e tambem, avaliar as variaveis de processo que influenciam na purificacao deste combustivel. A planta piloto e composta por um reator de vidro com capacidade de 3 L, provido de: camisa de circulacao de agua aquecida e agitacao mecanica. Os experimentos para o estudo da producao do biodiesel de soja foram realizados de acordo com o planejamento fatorial fracionado. Ja o estudo do processo de purificacao do mesmo foi realizado de acordo com um planejamento fatorial completo. As variaveis estudadas para o processo de producao foram: temperatura de reação (30-70 oC); concentracao de catalisador (0,5-1,5%); tempo de reacao (0,5-2 horas); velocidade de agitacao (150-350 rpm); e, razao molar etanol : oleo de soja (4:1-10:1). E as variaveis estudadas para o processo de purificacao foram: temperatura (30-70 oC) e pH da agua de lavagem (2-5). No estudo da producao de biodiesel de soja o parametro de avaliacao foi a conversao em biodiesel, determinada por cromatografia gasosa, utilizando o cromatografo VARIAN, modelo CP-3800; e para o estudo do processo de purificacao, o parametro de resposta foi a quantidade de agua gasta para neutralizar o biodiesel de soja. Ao final do trabalho foi verificado que as variaveis: razao molar oleo/alcool; temperatura da reacao e concentracao do catalisador tem forte influencia no processo de producao do biodiesel. E que a temperatura e o pH da agua de lavagem exercem forte influencia no processo de purificacao do biodiesel de soja.