Impact of the catalytic activity of iodine on the granule morphology, crystalline structure, thermal properties and water solubility of acetylated corn (Zea mays) starch synthesized under microwave assistance

Acetylation of barnyardgrass starch with acetic anhydride under iodine catalysis

“…The sample preparation and analysis parameters were performed according to the recommendations of Diop et al (2011). Tablets were prepared from a mixture of the sample with KBr at a ratio of 1:100 (starch:KBr).…”

“…Recently, studies have shown that iodine is an excellent acylating agent in the acetylation of polysaccharides (Biswas, Shogren, & Willett, 2005;Diop, Li, Xie, & Shi, 2011;Ramírez-Arreola, RobledoOrtiz, Arellano, González-Núñez, & Rodrigue, 2009). Unlike the methods that require an alkaline pH to facilitate the displacement reaction to promote substitution, iodine acts as a Lewis acid catalyst by activating the carbonyl group of the acylating reagent, making it more reactive during synthesis.…”

“…However, only studies by Sánchez-Rivera et al (2010) with corn and banana starches, and by Diop et al (2011) with corn starch, provided information about the physical and chemical properties obtained by acetylation catalysed by iodine. Thus, the influence of the catalysis of iodine on the structural aspects, including the substitution pattern as well as physicochemical, rheological and functional characteristics, of these and other starch sources have not yet been elucidated.…”

Acetylation of banana (Musa paradisiaca L.) and corn (Zea mays L.) starches using a microwave heating procedure and iodine as catalyst: II. Rheological and structural studies

“…The esterification of starch can be accelerated by heating the reaction mixture in a pressurized vessel using a microwave oven since high temperatures can be reached rapidly through microwave heating. The esterification reaction rate can be increased with the addition of iodine (I 2 ) as a catalyst because this activates the carbonyl carbon of acetic anhydride, making the latter more reactive (Diopa, Li, Xie, & Shi, 2011). The advantage of a microwave-assisted reaction is that it provides fast and uniform heating (Shogren & Biswas, 2006) and is economical and environmentally friendly due to minimizing the energy consumption, level of solvent toxicity, amount of catalyst needed, and by-products (Biswas et al, 2008).…”

Nanocomposites of crosslinked starch phthalate and silane modified nanoclay: Study of mechanical, thermal, morphological, and biodegradable characteristics

“…The peak at 3487 cm À1 depicts the unreacted hydroxyl groups while the peak for -CH 3 symmetric deformation is at 1388 cm À1 [16,17]. For the crosslinked Stph (XStph), a broad peak for -O-H-stretching is at 3444.6 cm À1 , while the peaks at 1280 and 1074 cm À1 are for P --O and C-O-P stretching respectively.…”