The Preparation of Soluble Cellouronic Acid Sodium Salt by 4-Acetamide-TEMPO Mediated Oxidation of Ultrasound-Pretreated Parenchyma Cellulose from Bagasse Pith

Abstract

The parenchyma cellulose isolated from bagasse pith was used as an alternative resource for preparation of water-soluble cellouronic acid sodium salt (CAS). The influence of ultrasound treatment on the cellulose was investigated for obtaining CAS by regioselective oxidization using 4-acetamide-TEMPO and NaClO with NaClO2 as a primary oxidant in an aqueous buffer at pH 6.0. The yield, carboxylate content and polymerization degree (DP) of CAS were measured as a function of ultrasonic power, agitating time and cellulose consistency by an orthogonal test. The ultrasound-treated conditions were further improved by discussion of ultrasonic power, the most important factor influencing the yield and DP. An optimized CAS yield of 72.9% with DP value (DPv) of 212 was found when the ultrasonic strength is 550 W, agitating time is 3 h and cellulose consistency is 2.0%. The oxidation reactivity of cellulose was improved by ultrasonic irradiation, whereas no significant changes in crystallinity of cellulose were measured after ultrasonic treatment. Moreover, the ultrasound treatment has a greater effect on yielding CAS from parenchyma cellulose than from bagasse fibrous' one. The CAS was further characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM).

Activation behavior of 4-AcNH-TEMPO by ClO2 for selective oxidation of cellulose in DMAc/LiCl system

“…This could be attributed to the difference in microstructures between parenchyma cell cellulose and fibrous cellulose. The microfibrillar cellulose crystals within parenchyma showed a less ordered arrangement than those found in the fibers (Gao et al 2014a). The loose arrangement of cellulose chains in the parenchymal cells was corroborated with the notably lower cell wall density (1.28 vs 1.52 g/cm³) and increased porosity (0.013 vs 0.007 cc/g following chemical pretreatments), in comparison to the fibrous one (Zhang et al 2022b).…”

Characterization of cationic parenchyma cellulose derivative by rapid preparation of low microwave power

“…It is noticed that cellulose microfibrils in the parenchyma cell walls are less uniform in diameter and less aligned than those in fibrous cells [25]. We reported a green ultrasound pretreatment of celluloses from the two different cells in order to improve the selective oxidation for the preparation of water-soluble oxycellulose [26]. The results showed that ultrasonic treatment of parenchyma cellulose (PC) had more effect on its yield than that of fibrous cellulose.…”