Etherification Of Cellulose Research Articles

Thermochemistry of alkalization and etherification of cellulose

In this research, the process of alkalization of cotton cellulose with solutions of sodium hydroxide of different concentrations has been studied. It was found that the enthalpy of cellulose alkalization is exothermic. Moreover, the exothermic enthalpy value of cellulose alkalization with 30-40% NaOH solutions is higher than with 16-20% alkalis. Thus, the cellulose treatment with 30-40% alkalis provides the formation of more reactive alkali cellulose. In addition, the determination of the formation enthalpy of alkali celluloses showed that this thermochemical characteristic is also exothermic, and therefore, the process of cellulose alkalization is energetically favorable. It is most likely that cellulose alkalization is a physicochemical process of forming a molecular adduct of hydrated hydroxide ions with cellulose. A study of the methylation reaction of alkali cellulose with methyl chloride to a degree of substitution of 1.3-1.8 showed that the enthalpy of this reaction is quite exothermic. This means that methylation reaction is energetically advantageous, and obtaining methylcellulose with a higher degree of substitution is preferable.

One-pot preparation of amphoteric cellulose polymers for simultaneous recovery of ammonium and dihydrogen phosphate from wastewater and reutilizing as slow-release fertilizer

In this paper, a simple approach was developed to prepare amphoteric cellulose adsorbent (EAC) through etherification of cellulose with glycidyl trimethyl ammonium chloride (ETA) and glycidylsulfonoic acid sodium salt (SEP) in a one-pot reaction system. The effect of the molar ratio of cellulose to ETA and SEP on the contents of sulfur and nitrogen elements in the EAC was evaluated with the aim of deriving the adsorbents with amounts of ionic functional groups. The EAC was examined for adsorption to NH4+ and H2PO4- ions. Meanwhile, the effect of adsorption parameters, including dosage of EAC, pH value of solution, contact time and ionic strength, on its adsorption capacity was also analyzed. The EAC displayed excellent affinity to the targeted ions, with an adsorption capacity of 40.38 mg/g for NH4+ and 30.42 mg/g for H2PO4-. The adsorption of EAC for NH4+ and H2PO4- reached equilibrium within 30 min and was fitted by second-order and Langmuir models well. More importantly, the EAC after adsorption could be recovered and recycled as a slow-release fertilizer, which could release approximately 95.5% of NH4+ and 92.5% of H2PO4− within 30 days. The results demonstrated that the EAC after adsorption would be reutilized as a slow-release fertilizer, which would give highlights on cost-effective and eco-friendly development in agriculture.

Application of modified cellulose-based antiscalant in reverse osmosis membrane scaling control

<p indent=0mm>Applying membrane scaling is a key problem in reverse osmosis (RO) desalination processes. By dosing antiscalant, we can effectively inhibit inorganic scale and control RO membrane scaling. Accordingly, in this work, an environmentally friendly modified cellulose-based antiscalant is synthesized by the etherification of cellulose and subsequent graft copolymerization using the etherification product carboxymethyl cellulose (CMC), acrylic acid (AA), and sodium allyl sulfonate (SAS): CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS). The influence of molecular structure, CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS) dose, and coexisting anions with respect to inhibiting the calcium-sulfate scale in the RO system are investigated. The results indicate that dosing CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS) can significantly prolong the induction time of calcium-sulfate crystallization, inhibit the formation of calcium-sulfate scale, greatly alleviate both membrane fouling and membrane flux decline caused by membrane-surface scale formation, and effectively improve the membrane filtration efficiency. Static tests, scanning electron microscopy, optical microscopy, X-ray diffraction, conductivity measurements, and dispersion experiments suggest that the scale inhibition mechanism of CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS) can be attributed to the chelation and dispersion effects of the introduced anionic groups, and that the carboxyl groups are more efficient in the inhibition of calcium-sulfate scale than the sulfonic groups. In addition, an appropriate number of sulfonic groups on the graft chain of CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS) can improve the water solubility of CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS), as well as effectively stabilize the scale-formed substances and enhance the scale inhibition efficiency. If the proportion of sulfonic groups is too high, the content of the carboxyl groups decreases accordingly, which reduces the chelation and dispersion effects of CMC-<italic>g</italic>-P(AA-<italic>co</italic>-SAS), which, in turn, reduces the scale inhibition performance.

Effects of carboxymethyl cellulose grafting on stability and reactivity of zerovalent iron in water systems

The present study investigated the effects of degree of substitution (DS) and grafting method (pre-grafting or post-grafting) of carboxymethyl cellulose (CMC) on particle size, surface chemistry, colloidal and oxidative stability and reactivity of zerovalent iron (ZVI) particles. CMC with different DS were systematically synthesized by etherification of cellulose using monochloroacetic acid (MCA) in alcoholic medium. Structural Identity and purity of CMC was confirmed using NMR, FTIR and XRD analyses. It was found that DS of CMC can regulate the particle size, stability, dispersibility and reactivity of stabilized ZVI particles. CMC stabilized ZVI particles had smaller particle size, higher surface area and high dispersibility as compared to bare ZVI particles. Further, less aggregation was observed in higher DS CMC stabilized ZVI samples compared to lower DS CMC stabilized ZVI samples due to the better shielding ability for van der waals attractive forces. Also, the reactivity of stabilized ZVI particles was better than bare ZVI particles as the complete degradation of naphthenic acid was achieved in 180 min (>95% in 60 min). The colloidal stability and reactivity of stabilized ZVI particles remained intact even after 6 months of storage. Overall, CMC was found most efficient in colloidal stabilization of ZVI particles both in pre-grafting as well as post-grafting mode.

Application of CMC from Oil Palm Biomass as Anti-Redeposition Agent in Laundry Detergent

This research was focused on the utilizing one of palm oil biomass; the palm pressed fibre (PPF) for producing CMC through etherification of cellulose with monochloroacetic acid. The gained CMC fibre based was tested for its potential as anti-redeposition agent. The main objective was to synthesize cellulose and carboxymethyl cellulose value added product from oil palm biomass PPF using established standard method of ASTM (American Standard Test Method) and to run quality control studies for all sample such as viscosity of CMC, purity of CMC, Fourier Transform Infrared Spectroscopy (FT-IR) and Thermal Gravimetric Analyzer (TGA) Analysis. The effect of the CMC as anti-redeposition agent in laundry detergent making was focused as the main potential. The produced CMC was excellent in quality and has imitated the standard CMC with degree of substitution of 0.7 rather than 0.9. By using the TGA analysis, the moisture, volatile, carbon and ash content of the CMC was valued as 14.79%, 40.29%, 8.32% and 17.93%, respectively. 1% CMC added into three (3) different types of detergents against number of wash cycle to avoid soil redeposited back to our laundry load with Yr/Yo represents the whiteness retention in fabric swatches. Five wash cycles with duration of 10 minutes for each cycle was chosen since there was possibility that within minimum cycle of 1-2 detergent performance is still at its best. Detergent A + 1% (w/v) CMC has proved to give significant brightness of 59% better than Detergent A without CMC. CMC produced and reported in this paper has been proved to own such a potential and is expected to achieve interesting quality with better research exposure or maybe through a great pilot plant scale of CMC-antiredeposition-detergent with real dirty clothing-real washing machine test. Keywords. Palm Pressed Fibre; CMC (Carboxymethyl Cellulose); anti-redeposition

Hydrogen-bonded thin films of cellulose ethers and poly(acrylic acid)

Etherification of cellulose can get a series of water soluble derivatives, which can form hydrogen-bonded polymer complex with poly(acrylic acid) (PAA). Three cellulose ethers hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC) and methyl cellulose (MC) are LbL assembled with PAA to fabricate thin films. The hydrogen bonding of the films is characterized with FT-IR. The film growth behaviors are monitored by a quartz crystal microbalance (QCM) and a spectroscopic interferometer, which shows a different growth rate for different system and a strong dependence on pH values. The stability of the films can be increased by heat treatment. Once the cross-linked structure is formed, and the dissolution of film can be prevented even in the high pH value. In addition, the films show good water adsorption ability from environment. Owing to pH responsive behavior and good water adsorption, CE/PAA films can be explored for various applications, especially for biomedical application.

Binary Ionic Liquid System for Direct Cellulose Etherification

Etherification of cellulose was performed using a mixture of ionic liquids (ILs) playing roles in both cellulose dissolution and catalysis. We investigated the effects of the reaction time and the ratio of these ILs in the mixture. Cellulose etherification was performed in these IL mixtures. The proportion of propoxy cellulose exceeded 2.5 after 24 h.

Etherification of Cellulose in Binary Ionic Liquid as Solvent and Catalyst

Etherification of cellulose, in particular, its epoxidation in the presence of glycidol, was conducted using a binary ionic liquid mixture as the solvent and catalyst. The influence of reaction time and component ratio was studied. The degree of cellulose epoxidation exceeded 2.2 at 60 °C for 18 h.

Synthesis of O‐(2,3‐dihydroxypropyl) cellulose in NaOH/urea aqueous solution: As a precursor for introducing “necklace‐like” structure

ABSTRACTO‐(2,3‐dihydroxypropyl) cellulose (DHPC) samples were synthesized by etherification of cellulose with glycidol (GLY) in a NaOH/urea aqueous solution system under different reaction conditions, so that they had different degrees of ether substitution (DS) in both the overall and regional distributions. The characterization was made by NMR spectroscopy in order to clarify the effects of the molar ratio of in‐fed GLY to anhydroglucose unit and of the reaction temperature not only on the total and regional DSs but also on the molar substitution (MSdhp) for the multireactive dihydroxypropyl group. The evaluation of MSdhp was performed after complete propionylation of each DHPC sample. Determination of molecular weights was also conducted on the propionylated DHPCs by GPC analysis. As a preliminary extension, butyralization of DHPC was undertaken in aqueous solution by using p‐toluenesulfonic acid as catalyst together with butyraldehyde (BuA). Two‐dimensional NMR (1H–13C gHSQC) spectra measurements revealed that the products contained butyral groups, owing to dehydration‐cyclization between the BuA‐carbonyl and the duplicate hydroxyls in the side chain of DHPC. Such butyral derivatives of cellulose are expected to be a promising functional material parallel or superior to poly(vinyl butyral) available for safety glass interlayers, etc. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3590–3597

Regioselective Esterification and Etherification of Cellulose: A Review

Deep understanding of the structure-property relationships of polysaccharide derivatives depends on the ability to control the position of the substituents around the monosaccharide ring and along the chain. Equally important is the ability to analyze position of substitution. Historically, both synthetic control and analysis of regiochemistry have been very difficult for cellulose derivatives, as for most other polysaccharide derivatives. With the advent of cellulose solvents that are suitable for chemical transformations, it has become possible to carry out cellulose derivatization under conditions sufficiently mild to permit increasingly complete regiochemical control, particularly with regard to the position of the substituents around the anhydroglucose ring. In addition, new techniques for forming cellulose and its derivatives from monomers, either by enzyme-catalyzed processes or chemical polymerization, permit us to address new frontiers in regiochemical control. We review these exciting developments in regiocontrolled synthesis of cellulose derivatives and their implications for in-depth structure-property studies.

Carboxymethylation of cellulose in unconventional media

Carboxymethylation of cellulose in the new and highly efficient aqueous solvent Ni(tren)(OH)2 (trenDtris(2-aminoethyl)amine) and in melts of LiClO4 3H2 Oo rN-methyl- morpholine-N -oxide (NMMNO), which is now widely applied for cellulose fibre production, was investigated. In case of Ni(tren)(OH)2, a totally homogeneous carboxymethylation of cellulose with sodium monochloroacetate, in the presence of an aqueous NaOH solution is possible for the first time. Structure analysis by means of HPLC and 1 H-NMR after chain degradation showed results comparable with findings for CMC obtained by the heterogeneous slurry process, that is, a statistic distribution of substituents along the polymer chain and functionalisation of the hydroxyl groups in the order C-6 C-2> C-3. The etherification of cellulose in a melt of LiClO43H2O, a new type of cellulose solvent, was shown to be possible and gave products of a statistic functionalisation pattern as well. In contrast, carboxymethyla- tion starting from solutions of cellulose in NMMNO initiated with solid NaOH particles yields polymers with a nonstatistic distribution of functional groups along the chain, as observed for cellulose ethers prepared in reactive microstrctures starting from solutions of cellulose inter- mediates in dimethyl sulfoxide as well as of unmodified cellulose dissolved in N,N-dimethyl acetamide/LiCl.

Thiol and disulphide derivatives of cellulose

The acid catalyzed etherification of cellulose with 1-chloro-2,3-epoxypropane yielded 3-chloro-2-hydroxypropylcellulose (SCl ≤ 0.67); the latter, by a known sequence of reactions through the thiosulphate derivative and after its reduction, gave 2-hydroxy-3-mercaptopropylcellulose (up to 0.43 mmol SH/g). Mercaptodeoxycellulose (up to 0.53 mmol SH/g) was prepared from the less reactive chlorodeoxycellulose by an analogous sequence of reactions. Bead mercaptodeoxycellulose is more advantageous obtained by using tosylate of bead cellulose; this procedure is also more advantageous than the preparation of bead 2-hydroxy-3-mercaptopropylcellulose. Disulphide derivatives of cellulose were prepard (a) by a quantitative reaction of thiol derivatives with 2,2'-dipyridyl disulphide and (b) by a reversible crosslinking of cellulose or carboxymethylcellulose with bifunctional disulphides. Disulphide derivatives of cellulose prepared by procedure (b) give after reduction thiol derivatives (up to 0.185 mmol SH/g), and further by employing procedure (a) yield 2-pyridyl disulphide derivatives.

Methylolamides containing amino acid groups: Their use as wash-wear finishing agents for cotton

The acid-catalyzed etherification of cellulose with methylolamides containing a tertiary amino group is often inhibited by the presence of this basic group. In the production of wash-wear fabrics an incomplete reaction generally produces a low degree of wrinkle resistance and/or leaves the treated fabric susceptible to deterioration during use. In this work it is postulated that the insertion of a carboxylic acid group into such a crosslinking agent neutralizes the basic group by the formation of an inner salt (zwitterion). Such agents were prepared by methylolation of the products of a Michael addition of the sodium salt of selected amino acids to acrylamide. All the compounds synthesized are thought to be new. Those which were isolated and characterized include sodium N-2-carbamoylethylglycinate, sodium N,N-bis(2-carbamoylethyl)glycinate, N,N-bis(2-carbamoylethyl)glycine, sodium N,N-bis(2-carbamoylethyl)α-alaninate, and N,N-bis(2-carbamoylethyl)-α-alanine. Similar adducts from β-alanine, lysine, and aspartic acid were prepared; however, the adducts obtained were oils, and this complicated their isolation and characterization. For textile treatments isolation of the intermediates is unnecessary. The N-methylol crosslinking agents derived from these Michael adducts are highly reactive to cotton, as indicated by high add-ons at relatively mild conditions. The treated fabrics are highly wrinkle resistant and possess other desirable properties. The data obtained from the use of these agents indicate that further study is desirable, based on the concept developed in this work.