Carbamation of Starch with Amine Using Dimethyl Carbonate as Coupling Agent

Abstract

A one-pot coupling of starch with alkyl amine was studied using dimethyl carbonate (DMC) as the coupling agent. Although reaction occurred without a catalyst (24 h, 70 °C), different catalysts, namely, imidazole, tetramethylguanidine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and combinations thereof were investigated to improve the reaction efficiency. When 20 mol % DBU was used as a catalyst, the degree of substitution (DS) could be improved from 0.05 to 0.15 compared to the noncatalyzed reaction. When the amount of DBU was decreased to 5 mol %, catalytical activity remained, albeit with a slightly lower DS (0.09). Temperature did not have a significant effect on the DS but it could be used to alter the solubility of the product. Based on chemical analysis, the alkyl group was attached to starch by the formation of a carbamate group. As the carbonyl carbon in the carbamate originated from DMC, which, in turn, can be produced from carbon dioxide on an industrial scale, the current study provides a conventional way to utilize carbon dioxide-based chemicals in the functionalization of a natural polymer. DMC is also biodegradable and classified as a nonvolatile organic component, making it an environmentally desirable coupling agent.

A Fast Dissolution Pretreatment to Produce Strong Regenerated Cellulose Nanofibers via Mechanical Disintegration

“…Despite many advantages of oil-based materials, such as plastics, their environmental friendliness is compromised due to the nonrenewability of their raw material, poor biodegradability, and toxicity. The sustainable use of naturally occurring components, such as cellulose, , hemicelluloses, , lignin, , and starch, , among others, − in place of plastic could overcome the above-mentioned shortcomings.…”

A Temperature Responsive Polysaccharide Derivative in Aqueous Solution: Amylose Ethyl Carbamates

“…[27][28] The degree of substitution DS for which full substitution is defined as DS = 3 was determined from the weight ratio of carbon to nitrogen atoms which were determined by ultimate analysis. In the present study, we chose the conventional method to obtain AEC while a modern procedure without hazardous reagents 29 could be applicable to synthesize low DS samples.…”

“…The chemical structure of the purified samples was confirmed by 1 H NMR in deuterated dimethyl sulfoxide with a small amount of (trimethylsilyl)-1-propanesulfonic acid sodium salt (Figure S1) whereas the intensity of each peak cannot be estimated properly as in the case of our previous study for fully substituted derivatives. , The degree of substitution DS for which full substitution is defined as DS = 3 was determined from the weight ratio of carbon to nitrogen atoms which were determined by ultimate analysis. In the present study, we chose the conventional method to obtain AEC while a modern procedure without hazardous reagents could be applicable to synthesize low DS samples.…”

Revisiting Zeta Potential, the Key Feature of Interfacial Phenomena, with Applications and Recent Advancements

“…For example, precipitated CaCO 3 when modified with polyethyleneimine (PEI) is a positively charged surface, zeta potential +36 mV [115] . In another case, cationic starch when added with filler improved interaction occurs with filler and cellulose fiber [116] as shown in the Figure 41 below.…”