MPEG grafted alkylated carboxymethyl chitosan as a high-efficiency demulsifier for O/W crude oil emulsions

New synthetic chitosan derivatives bearing benzenoid/heterocyclic moieties with enhanced antioxidant and antifungal activities

“…As shown in the figure, the proton assignment of unmodified chitosan is as follows: chemical shifts at 3.13, 3.6-4.03, and 4.56 ppm are assigned to the hydrogen protons of [H2], [H3]-[H6], and [H1], respectively (Panda et al, 2019;Supapvanich et al, 2019). In 1 H NMR spectrum of CMCS, an obvious characteristic peak appears at 4.32 ppm, which can be assigned to CH 2 COOH, representing the successful synthesis of carboxymethyl chitosan (Lyu et al, 2020). As for the 1 H NMR spectrum of 2APCMCS, 3APCMCS,4APCMCS, new characteristic peaks appear at 6.89-8.01 ppm, confirming the successful introduction of pyridine (Zhang, Sun et al, 2020).…”

“…Compared to chitosan, carboxymethyl chitosan possesses good water solubility, which is attributed to the introduction of a hydrophilic group (carboxymethyl group). The improvement of water solubility greatly expands the application of https://doi.org/10.1016/j.carbpol.2020.116847 Received 28 May 2020; Received in revised form 27 July 2020; Accepted 28 July 2020 chitosan (Lyu et al, 2020). Meanwhile, many studies showed that carboxymethyl chitosan had potential applications in many fields.…”

“…For instance, it was reported that carboxymethyl chitosan showed enhanced antibacterial ability against Staphylococcus aureus and Escherichia coli (Zhang, Yang et al, 2020). Carboxymethyl chitosan was also reported to have anti-tumor activity, because carboxymethyl chitosan had stronger electrostatic interaction with negatively charged tumor cells, thus inhibiting the growth of tumor cells (Lei et al, 2020;Lyu et al, 2020). Besides, carboxymethyl chitosan possesses a promising application in antifungal and antioxidation fields due to its antifungal and antioxidant activities.…”

Enhanced antifungal activity of novel cationic chitosan derivative bearing triphenylphosphonium salt via azide-alkyne click reaction

“…The obtained mixture was cooled down and poured into 750 mL of absolute ethanol to afford some flavescent precipitate (Elemental analysis: C: 31.43%, N: 4.52%, H: 5.49%, C/N: 6.95, DS trimethyl : 0.59). Cationic propargyl chitosan derivative was then synthetized according to the similar protocol published by Lyu et al [36]. A 5% aqueous solution of NaOH (36 mL, 45 mmol) was added slowly to a solution of collected flavescent precipitate in NMP (150 mL).…”

Investigation of Dioctyl Sodium Sulfosuccinate in Demulsifying Crude Oil-in-Water Emulsions

“…As shown in Figure a, increasing DSS concentration to 900 mg/L increased the demulsification efficiency, and beyond this concentration, the improvement in demulsification efficiency was insignificant. It can be concluded that the critical micelle concentration (CMC) of DSS for O/W demulsification is 900 mg/L. , As listed in Table , increasing DSS concentration from 300 mg/L to 1300 mg/L reduced TEPH in separated water to <10 mg/L. This high demulsification efficiency of DSS may be because the double-chain structure facilitated the homogeneous distribution of DSS in the emulsion.…”