title: Organocatalytic acetylation of starch: effect of reaction conditions on DS and characterisation of esterified granules.
abstract: Starch acetates with varying degree of substitution (DS) were prepared by a novel solvent-free organocatalytic methodology. The acetylation protocol involved a non-toxic biobased α-hydroxycarboxylic acid as catalyst, and proceeded with high efficiency in absence of solvents. The effect of reaction conditions including reaction temperature (90-140 °C), catalyst load (0-2.3 g/g starch), acetic anhydride/starch weight ratio (6.5-13.5 g/g), and starch moisture content (0.6-14.8%) on the DS of the esters was evaluated. The analysis performed showed that the increase of temperature and catalyst concentration resulted in higher DS values, and evidenced a beneficial contribution of native starch moisture content on the substitution level achieved. Variation of reaction conditions allowed starch esters to be obtained with DS in the 0.03-2.93 range. Starch esters were characterised in terms of morphology, chemical structure, thermal properties, and distribution in polar/non polar liquid systems.
authors.affiliation: Grupo de Biotecnología y Biosíntesis - Instituto de Tecnología en Polímeros y Nanotecnología (ITPN) - Facultad de Ingeniería, Universidad de Buenos Aires, Las Heras 2214 (CP 1127AAR), Buenos Aires, Argentina.
authors.forename: Maribel Victoria
authors.initials: MV
authors.lastname: Tupa
authors.affiliation: Grupo de Biotecnología y Biosíntesis - Instituto de Tecnología en Polímeros y Nanotecnología (ITPN) - Facultad de Ingeniería, Universidad de Buenos Aires, Las Heras 2214 (CP 1127AAR), Buenos Aires, Argentina.
authors.forename: Jhon Alejandro
authors.initials: JA
authors.lastname: Ávila Ramírez
authors.affiliation: Grupo de Biotecnología y Biosíntesis - Instituto de Tecnología en Polímeros y Nanotecnología (ITPN) - Facultad de Ingeniería, Universidad de Buenos Aires, Las Heras 2214 (CP 1127AAR), Buenos Aires, Argentina.
authors.forename: Analía
authors.initials: A
authors.lastname: Vázquez
authors.affiliation: Grupo de Biotecnología y Biosíntesis - Instituto de Tecnología en Polímeros y Nanotecnología (ITPN) - Facultad de Ingeniería, Universidad de Buenos Aires, Las Heras 2214 (CP 1127AAR), Buenos Aires, Argentina. Electronic address: mforesti@fi.uba.ar.
authors.forename: María Laura
authors.initials: ML
authors.lastname: Foresti
mesh_terms: D000107:Acetylation; D002384:Catalysis; D012997:Solvents; D013213:Starch / Q000737:chemistry*; D013696:Temperature
chemical_list: D012997:Solvents; D013213:Starch
keywords: Acetylation; Characterisation; Organocatalysis; Reaction conditions; Starch