A atividade catalítica de sólidos ácidos como o fosfato de nióbio e a Amberlyst 35, uma resina trocadora de íons, foi avaliada na acetalização do hexanal com 2-etil-hexanol. Foram avaliadas a concentração do catalisador e a temperatura de reação na conversão do hexanal. A possibilidade de re-utilização do fosfato de nióbio também foi estudada e evidenciou ser possível re-utilizar este catalisador sem perda da atividade. O rendimento em acetal foi acima de 90% em condições brandas de reação.The catalyst activity of solid acids such as niobium phosphate and Amberlyst 35, an ion exchange resin, was evaluated in the acetalization of hexanal with 2-ethyl-hexanol. The catalyst loading and the reaction temperature were evaluated in the hexanal conversions. The possibility of recycling niobium phosphate was also studied, showing that it was possible to reuse this catalyst without significant loss in its catalytic activity. The yield in acetal was above 90% under mild conditions.
The efficiency of
electrostatic coalescence coupled with microwave
heating in separation of water-in-oil (W/O) model emulsions was evaluated.
A series of experiments were performed in a continuous pilot plant
where a W/O emulsion can be treated by application of electric field,
microwave heating, conventional heating, or a combination of these
techniques. The separation efficiencies in the two process configurations
were evaluated by measuring the water content of treated model emulsion.
The combination of electrocoalescence and microwave showed better
separation results, in comparison to conventional heating combination
with electrocoalescence. The influence of four operational variables
on the water contents of the treated emulsions were studied: salt
concentration, flow rate, the electric field between electrodes, and
water cut at the inlet were evaluated. It was observed that a lower
flow rate (higher residence time) helped in reducing the final water
content and that a higher salt content resulted in worse separation
efficiency. The microwave heating showed to be an attractive alternative
to conventional heating, particularly when the electrocoalescer is
under operational stress.
Encapsulated acids can increase the rate of penetration (ROP) during drilling operations by reacting with carbonate formations while avoiding corrosion of the metallic equipment parts. Drilling fluids can carry particles containing acid to the drilling tip where they will be mashed, and the acid released. The paraffin encapsulation is used in the processing of food ingredients, flavors, chemicals, drugs, protection of cosmetics, and in the oil industry. The novel solution presented in this paper is to use paraffin in the strong acid encapsulation to be added to the drilling fluid. Acid containing wax particles is prepared by the double emulsion technique. The results indicate that encapsulation efficiency is dependent on the wax to acid solution ratio and on acid concentration. Acid leakage is a significant concern; it is found to be directly dependent on acid concentration in the particle and on the particle wax fraction.
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