The kinetics of the homogeneous benzylation of potato starch in aqueous solutions

Modication of Heterocyclic Amino Acids: Histidine and Tryptophan

“…A detailed investigation into the benzylation of starch in water (NaOH, BnCl) was reported [20]. As expected, widespread hydrolysis of the BnCl occurred under these conditions.…”

Physico-chemical properties of solvent based etherification of sago starch

“…This nuclephile reacts with benzyl chloride to produce benzylated starch. As reported by Pieters et al (2003), the reaction rates are very dependent on the concentration of alkoxide ion (transition states) produced during the first stage of reaction (dissociation of proton from hydroxide ion in the starch main chain). This can be achieved via reducing the amount of water during reaction.…”

“…Since then, many researchers have studied the characteristics of the benzylated starch intensively. The process is an S N 2-nucleophilic substitution process (Williamson reaction) at the hydroxyl functional group of starch (Berkhout and Guns, 1973;Cho and Lim, 1998;Pieters et al, 2003;Bohrisch et al, 2004;Jaspreet et al, 2007;Sarka et al, 2012). Prior to etherification process, the starch was protonated by aqueous alkaline metal hydroxide, e.g., sodium hydroxide or potassium hydroxide, to form an alkoxide ion (RO − ) (Banks and Greenwood, 1975;Pieters et al, 2003).…”

“…As reported by Pieters et al (2003), benzyl chloride consumption can be determined by measuring the rates of hydroxide consumption in the reaction mixture. They found that, as the concentration of hydroxyl ion (contributed by sodium hydroxide) increases, the consumption of benzyl chloride also increases which reflecting an increase in the formation of benzylated starch.…”

“…Apart from that, the rates of benzylation also could be increased via increasing of reaction temperature (Pieters et al, 2003). Eventhough subjecting the starch at high temperature could lead into starch gelatinization (Ahmad et al, 1999;Karim et al, 2008;Suriani, 2002), the used of sulfate salt (sodium sulfate) could increased the initial gelatinization temperature, T gel (Sandstedt et al, 1960;Evans and Haisman, 1982) and hence prolong the gelatinization process to occur.…”