Banca de QUALIFICAÇÃO: MARIA BEATRIZ DE MENDONÇA GOIS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA BEATRIZ DE MENDONÇA GOIS
DATE: 16/05/2025
TIME: 08:00
LOCAL: on line
TITLE:

Study of the formulation of antifoams via esterification reaction with different carboxylic acids and emulsification of vegetable oil.

KEY WORDS:

antifoaming; foam; surfactants; esters; emulsions

PAGES: 73
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Orgânicos
SUMMARY:

Foams are metastable dispersions of gas in liquid, resulting from the reduction of the surface tension of the liquid mixture associated with a driving force, and in some industrial processes it is capable of causing significant production losses. Defoamers are agents applied in industrial processes whose objective is to inhibit bubble formation and/or destabilize the foam and can be based on oils, solid particles, surfactants, polymers and even emulsions. Thus, this work aims to study: (i) the formulation of defoamers produced via the esterification reaction of decanol with different carboxylic acids, evaluating the foam breaking in maple syrup; and (ii) the emulsification of vegetable oil with a calcium carbonate (CaCO₃) solution, using soap as an emulsifier, with the foam decay evaluated in a sodium dodecyl sulfate solution. Decanol esters were synthesized from formic, acetic, butanoic, levulinic, malic and oxalic acids, with zinc oxide as catalyst. They were characterized by GC-MS, TGA and FT-IR, and their surfactant properties were evaluated considering surface tension, wettability and balance hydrophilic-lipophilic (BHL). Regarding the emulsions, after their formulation, they were subjected to different stress conditions (refrigerator, oven and room temperature), monitoring their particle size, polydispersity index and zeta potential on days 1, 7, 14, 21 and 28 after their preparation in order to evaluate their stability. Finally, the study of the antifoaming potential of the esters and emulsions was performed using the Bikerman method. As a result, the esters proved to be a promising replacement for traditional vegetable oils used in maple syrup production, exhibiting excellent emulsifying and antifoaming properties, with emphasis on the oxalic acid derivative, decyl oxalate, which outperformed the commercial antifoam Atmos 300K. The emulsions showed that foam breaking efficiency is directly associated with particle size, so that the emulsion prepared with a 2% CaCO3 solution, with a particle diameter of 15.5 nm, had a foam breaking percentage of 67% after 30 min.

COMMITTEE MEMBERS:
Presidente - 1308273 - EDUARDO LINS DE BARROS NETO
Externo ao Programa - 1566922 - LINDEMBERG DE JESUS NOGUEIRA DUARTE - UFRNExterna à Instituição - PAULA FABIANE PINHEIRO DO NASCIMENTO - ISI-ER