Acetylation Of Cellulose Research Articles

Reaction behavior of solid acid catalytic cellulose acetylation

Reaction behavior of solid acid catalytic cellulose acetylation

Efficient synthesis of cellulose acetate through one-step homogeneous acetylation of cotton cellulose in binary ionic liquids

Cellulose acetate (CA) is an important cellulose derivative with a wide range of applications. To adopt a more efficient and environmentally friendly method to synthesize cellulose acetate, a binary ionic liquid mixture of 1-butyl-3-methylimidazole chloride salt (BmimCl) and 1-butyl-3-methyldihydroimidazole phosphate (BmimH2PO4) was used. Compared to the conventional methods, this approach didn't require pre-activation of cellulose and the process of homogeneous acetylation proceeded without a catalyst. By simply adjusting the reaction conditions, cellulose acetate with a degree of substitution (DS) in the range of 0.83–3.0 was produced by one-step homogeneous acetylation without hydrolysis. Furthermore, the cellulose acetate film produced by solvent casting exhibited smooth surface characteristics, 95 % transparency, and 57.9 MPa tensile strength. Therefore, this study highlights the importance of using binary ionic liquid mixtures for facile synthesis of cellulose acetate. Due to their excellent transparency and mechanical properties, newly synthesized cellulose acetate films could replace commercial films.

Cellulose, cellulose nanofibers, and cellulose acetate from Butia fruits (Butia odorata): Chemical, morphological, structural, and thermal properties

Cellulose possesses numerous advantageous properties and is a precursor to compounds and derivatives. The objective of this study was to isolate and characterize cellulose from Butia fruits and simultaneously produce cellulose nanofibers and cellulose acetate from the isolated cellulose. Cellulose extraction was performed using a combination of alkaline and bleaching treatments, while the production of cellulose nanofibers and cellulose acetate was achieved through acid hydrolysis and acetylation, respectively. The materials were characterized by their chemical composition, size distribution, zeta potential, morphology, relative crystallinity (XRD), functional groups (FTIR), molecular structure (NMR), and thermal stability (TGA). The Butia crude fibers presented 49.4 % cellulose, 4.5 % hemicellulose, 25.4 % lignin, and 1.3 % ash. The cellulose nanofibers presented an average diameter ranging from 13.7 to 93.1 nm and exhibited a high degree of crystallinity (63.3 %). FTIR, XRD, 13C, and 1H NMR analyses confirmed that the isolation processes effectively removed amorphous regions from the cellulose nanofibers and confirmed the cellulose acetylation process. As demonstrated, cellulosic materials derived from Butia fruit exhibit promise for various applications, including their potential use as reinforcing agents in polymer matrices, due to their high extraction yield, thermal properties, and crystallinity.

Cellulose acetylation in ionic liquid-molecular solvent mixtures: influence of the biopolymer-induced preferential solvation on its dissolution and reactivity

Cellulose acetylation in ionic liquid-molecular solvent mixtures: influence of the biopolymer-induced preferential solvation on its dissolution and reactivity

Enhancing cellulose acetate film with green plasticizers for improved performance, biodegradability, and migration study into a food simulant

Cellulose acetate (CA) is a synthetic compound obtained by acetylation of cellulose. It is widely used for various applications, including food packaging films. However, CA is very rigid due to the β-d-glycose ring in its main chain, and the presence of many hydrogen bonds between the hydroxyl groups, which limits the extent of its application. Therefore, plasticizers are generally used to provide flexibility particularly when used for packaging. The migration of plasticizers from packaging materials to packaged food can pose a risk to human health, particularly when the plasticizers present some levels of toxicity. The objective of this research is to compare the effect of widely used plasticizers glycerol, tris (2-ethylhexyl) phosphate (TEHP) and rosemary essential oil on the properties of cellulose acetate films for food packaging. Cellulose acetate films were prepared via solvent casting method followed by plasticizing. The films prepared were characterized using infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-Ray diffraction analysis (XRD) and others analysis. The results show that rosemary essential oil has the lowest migration rate to food simulants. Rosemary can play dual roles, a plasticizer by improving mechanical properties and an active agent (antioxidant, antimicrobial, and UV protector, and promotor of biodegradability). The results show the potential of rosemary essential oil as an additive for application in food packaging.

Acetylation of cellulose in ethyl acetate: characterization and thin film applications

The study aims to explore the viability of ethyl acetate as a solvent for cellulose acetylation and assess the feasibility of producing films from the acetylated cellulose. Methodologically, the research focused on limited variations in reaction temperature and catalyst amount, specifically two temperatures and four catalyst quantities, while maintaining consistent quantities of EtoAc and acetic anhydride, reaction time, solution concentration, and other factors. The structure and properties of acetylated cellulose were investigated by titration (heterogeneous saponification), viscosity, chemical resistance (solubility), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), proton nuclear magnetic resonance (1H-NMR) and differential scanning calorimetry (DSC). Surprisingly, efficient acetylation in ethyl acetate was achieved with a small catalyst quantity. As the catalyst amount increased, degree of substitution decreased from 2.32 to 0.76. Further investigation involved the production of thin acetate films using the casting method, and evaluating film properties such as ultraviolet (UV) light absorbance, water vapor permeability, tensile strength, and cross-sectional characteristics via scanning electron microscopy (SEM). The films exhibited impressive tensile strengths, reaching up to 76.98 MPa, and demonstrated exceptional transparency. The findings suggest that EtoAc is a suitable solvent for synthesizing cellulose acetate, and adjustments to reaction variables hold the potential to enhance product qualities.

Textile finishing for bacterial cellulose modification: organic acid-catalyzed cellulosic acetylation

Bacterial Cellulose (BC) is an originally sustainable material for the textile and leather industries. However, dehydrated BC faces challenges: excessive stiffness, low density, surface defects, high roughness, etc. That reduces appeal in applicability. To address these issues, this study introduces a textile finishing method involving cellulose acetylation catalyzed by organic acids, namely Citric Acid and Succinic Acid. The acetylation-finished BC samples, catalyzed by Citric Acid (BC/AA/CA) and Succinic Acid (BC/AA/SA), exhibit improved softness with bending modulus of 62.65 ± 5.87 and 99.82 ± 25.25 MPa, respectively, as compared to untreated BC (1956.51 ± 426.12 MPa), tensile strength of 15.10 ± 1.42 MPa for BC/AA/CA and 15.02 ± 0.74 MPa for BC/AA/SA, porosity, and significant alterations in thermal stability. The study explores a novel “self-patterning” mechanism during BC acetylation finishing. Consequently, this study addresses the limitations of BC in its dehydrated state and promises practical and valuable scientific contributions toward long-term sustainability.

Preparation and Characterization of Cellulose Derivatives from Agricultural Wastes

Background: Rice straw was pretreated with dilute alkaline and acid solutions to extract cellulose, which was then converted into cellulose acetate with acetic anhydride and phosphotungstic acid (H3PW12O40·6H2O). The concentration of KOH and the duration of immersion in acetic acid solution affected the removal of hemicellulose and lignin, and after pretreatment with 4% KOH and immersion in acetic acid for 5 hours, the treated rice straw contained 83wt.% cellulose. Phosphotungstic acid has been shown to be an excellent catalyst for the acetylation of rice straw cellulose. The degree of substitution (DS) values had a substantial effect on the solubility of cellulose acetate, and acetone-soluble cellulose acetate with DS values about 2.2 can be generated by varying the amount of phosphotungstic acid and acetylation duration. Objectives: The aim of the study was to evaluate the preparation and characterization of cellulose derivatives from agricultural wastes. Methods: This cross-sectional study was carried out in the Department of Communicable Diseases Control, Director General of Health Services, Dhaka, Bangladesh. For this investigation the rice plant straw was collected from Magura district region. The collected straws were then treated with 3 wt% nitric acid and 1.5 wt% NaOH solution separately. Statistical analyses of the results were be obtained by using window-based Microsoft Excel and Statistical Packages for Social Sciences (SPSS-24). Results: This study observed that the rice straw contained about 35.67% cellulose, 5.50% hemicellulose and 30.18 % α-cellulose. And the wheat straw contained about 43.99% cellulose, 7.30% hemicellulose and 36.70% α-cellulose. The degree of acetylation and degree of substitution of the synthesized cellulose acetate from rice straw were 39.046% and 2.413 respectively. On the other hand, the degree of acetylation and degree of substitution of the synthesized cellulose acetate from wheat straw were 40.79% and 2.59 respectively. ....

Preparation and characterization of corn cob cellulose acetate for potential industrial applications

Background: Locally generated biopolymers are amenable to further processing to widen their industrial applications. The study was aimed at generating low-cost cellulose acetate from corn cob residue and its characterizations for potential applications in biopolymer industries. Methods: Cellulose was extracted from the corn cob residue using the sodium hydroxide method. Acetylation of the cellulose to obtain corn cob cellulose acetate was carried out by adding appropriate quantities of a glacial acetic and acetylating mixture of acetic anhydride and sulphuric acid. The corn cob native cellulose and corn cob cellulose acetate were characterized using scanning electron microscopy (SEM) to examine their morphology, Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD) for structural elucidation while differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were employed to investigate their thermal properties. Results: - Two corn cellulose acetate samples with degree of substitutions 1.87 and 2.65 for samples CDA and CA respectively were obtained. They had improved solubilities in some organic solvents compared to the corn cob cellulose. The SEM examination showed the surface of the corn cob native cellulose (NC) was smooth and had a regular bundle-like structure while acetylation destroyed the original cellulose structure. Cellulose acetate samples showed a cluster-like structure with different sizes and a rough flake-like surface. FTIR and XRD studies showed that acetyl groups substituted cellulose hydroxyl groups. While FTIR study showed that the cellulose acetates had sharp bands between 1728 cm-1 to 1733 cm-1 and around 1368 cm-1 wavenumber unlike the corn cob cellulose sample, the data generated from XRD study indicated that acetylation of the corn cob cellulose led to 47% and 77% decrease in the crystallinity of CDA and CA samples respectively. The thermal analysis data from DSC and TGA studies confirmed that the acetylation improved the corn cob cellulose's thermal stability as indicated by the degradation of cellulose acetate samples at higher temperatures. Conclusion: The study concluded that low-cost cellulose acetate generated from corn cob residue could be potentially employed as a renewable, biodegradable, biocompatible polymer for industrial applications.

Biomass derived fibrous porous carbon loaded zinc oxide nanoparticles as high-performance anode materials for lithium ion batteries

The use of absorbent cotton as a biomass-derived carbon skeleton has been rarely reported. In this study, zinc oxide (ZnO) was loaded on the surface of a fibrous structure derived from absorbent cotton porous carbon (PC), thereby improving its electrochemical and rate performances. The reversible capacity of the as-fabricated ZnO@PC composite, used as anode material, reached 611.0 mAh g−1 after 200 charge–discharge cycles, and its full-battery electrochemical performance was excellent. After 880 cycles, the full-battery capacity retention rate reached 74.85 %. The improvement in the electrochemical performance of the ZnO@PC composite is attributed to (1) the introduction of N-doped carbon skeletons into the composite to improve its electrical conductivity, (2) promoting effect of the fibrous structure on the electrochemical stability of the composite, the CO group was introduced into the system during the acetylation of cellulose with CH3COO−, which gives the composite higher binding energy with Li+ increases the full battery long cycle life, and (3) increase in the number of electrochemically active sites due to the large specific surface area of the composite. The as-fabricated composite can be used in high-performance lithium-ion batteries.

Improving the Cellulose Enzymatic Digestibility of Sugarcane Bagasse by Atmospheric Acetic Acid Pretreatment and Peracetic Acid Post-Treatment.

Pretreatment of sugarcane bagasse (SCB) by aqueous acetic acid (AA), with the addition of sulfuric acid (SA) as a catalyst under mild condition (<110 °C), was investigated. A response surface methodology (central composite design) was employed to study the effects of temperature, AA concentration, time, and SA concentration, as well as their interactive effects, on several response variables. Kinetic modeling was further investigated for AA pretreatment using both Saeman's model and the Potential Degree of Reaction (PDR) model. It was found that Saeman's model showed a great deviation from the experimental results, while the PDR model fitted the experimental data very well, with determination coefficients of 0.95-0.99. However, poor enzymatic digestibility of the AA-pretreated substrates was observed, mainly due to the relatively low degree of delignification and acetylation of cellulose. Post-treatment of the pretreated cellulosic solid well improved the cellulose digestibly by further selectively removing 50-60% of the residual linin and acetyl group. The enzymatic polysaccharide conversion increased from <30% for AA-pretreatment to about 70% for PAA post-treatment.

Cellulose acetate from lignocellulosic residues: An eco-friendly approach based on a hydrothermal process

The objective of this study was to produce cellulose acetate (CA) from oat (OH) and soybean (SH) hulls through an eco-friendly solvent-and catalyst-free hydrothermal process, and also to compare the acetylation of cellulose by the conventional synthesis process, employing sulfuric acid as the catalyst, and acetic acid as solvent. Cellulose was extracted from OH and SH using a one-step chlorine-free process, resulting in materials with 86 and 81 % cellulose, respectively. CA samples obtained by hydrothermal process had degrees of substitution ranging from 0.95 to 1.47, and from 1.10 to 1.50, for OH and SH samples, respectively, being classified as monoacetates, while the conventional acetylation resulted in cellulose di- and triacetates. The acetylation by the hydrothermal process did not affect cellulose fibers morphology or crystallinity. CA samples obtained by the conventional process showed changes in their surface morphology, with decrease in crystallinity indexes. Viscosimetric average molar mass increased for all modified samples, with mass gain ranging from 16.26 to 519.70 %. The hydrothermal treatment proved to be a promising process for obtaining cellulose monoacetates with some advantages, including short reaction times, it is a one-step process, and lower effluents generation when compared to the conventional processes.

WssI from the Gram-negative bacterial cellulose synthase is an O-acetyltransferase that acts on cello-oligomers with several acetyl donor substrates

In microbial biofilms, bacterial cells are encased in a self-produced matrix of polymers (e.g., exopolysaccharides) that enable surface adherence and protect against environmental stressors. For example, the wrinkly spreader phenotype of Pseudomonas fluorescens colonizes food/water sources and human tissue to form robust biofilms that can spread across surfaces. This biofilm largely consists of bacterial cellulose produced by the cellulose synthase proteins encoded by the wss (WS structural) operon, which also occurs in other species, including pathogenic Achromobacter species. Although phenotypic mutant analysis of the wssFGHI genes has previously shown that they are responsible for acetylation of bacterial cellulose, their specific roles remain unknown and distinct from the recently identified cellulose phosphoethanolamine modification found in other species. Here, we have purified the C-terminal soluble form of WssI from P.fluorescens and Achromobacter insuavis and demonstrated acetylesterase activity with chromogenic substrates. The kinetic parameters (kcat/KM values of 13 and 8.0 M-1 s-1, respectively) indicate that these enzymes are up to four times more catalytically efficient than the closest characterized homolog, AlgJ from the alginate synthase. Unlike AlgJ and its cognate alginate polymer, WssI also demonstrated acetyltransferase activity onto cellulose oligomers (e.g., cellotetraose to cellohexaose) with multiple acetyl donor substrates (p-nitrophenyl acetate, 4-methylumbelliferyl acetate, and acetyl-CoA). Finally, a high-throughput screen identified three low micromolar WssI inhibitors that may be useful for chemically interrogating cellulose acetylation and biofilm formation.

Improved performance of metal-organic frameworks loaded cellulose acetate based film for packaging application

Bio-nanocomposite-based packaging materials have gained significance due to their possible applications in food packaging. Cellulose acetate is a biopolymer obtained by acetylation of cellulose and has characteristics such as biocompatibility, biodegradability and high transparency. Introducing iron-based metal-organic frameworks offer good mechanical strength, unique surface area and both chemical and thermally stability, making them favourable as supporting materials in fabricating polymer-based packaging materials. Among them, Fe- (Material Institute Lavoisier) MIL-88A is an iron-based nontoxic metal-organic framework, integrated with cellulose acetate and spinach extract was added to the prepared material in different compositions and cast as film. The Spinach loaded, Fe- (Material Institute Lavoisier) MIL-88A integrated cellulose acetate film significantly enhanced the tensile strength, water vapour permeability, and anti-microbial activity. The prepared film is then characterized using a scanning electron microscope (SEM), Fourier transforms infrared spectrometer (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Further, studies on mechanical properties as well as degradation tests and real-time applications of the prepared films were carried out.

Synthesis and Characterization of Corn Stover-Based Cellulose Triacetate Catalyzed by Ionic Liquid Phosphotungstate.

Cellulose triacetate (CTA) was successfully synthesized from corn stover cellulose (CSC) in the presence of [PyPS]3PW12O40 (IL-POM). The effects of IL-POM contents, reaction temperature, and reaction time on the yield and degree of substitution of CTA were investigated. The synthesized CTA was characterized by SEM, FTIR, and TGA, and the degree of polymerization and solubility in various organic solvents were evaluated. Results showed that the optimum reaction conditions were as follows: 0.04 g of IL-POM, reaction temperature of 140 °C, and reaction time of 45 min, for 0.4 g of CSC and 9 mL of glacial acetic acid. The yield of CTA under optimum reaction conditions was as high as 79.27%, and the degree of substitution was 2.95. SEM and FTIR results showed that the cellulose acetylation occurred, and CTA was synthesized. The TGA results revealed that the decomposition temperature of CTA increased by about 30 °C when compared with that of CSC. A simple, environment-friendly, and efficient process for the preparation of CTA from CSC was constructed, which provides a new pathway for the high-value utilization of corn stover.

Acetylation of Bacterial Cellulose from a Mixture of Palm Flour Liquid Waste and Coconut Water: The Effect of Acetylation Time on Yield and Identification of Cellulose Acetate

Cellulose acetate is a promising thermoplastic polymer to be developed since it has some characteristics, among others are easy to be formed, non-toxic, high stability, and its raw materials are renewable. The most used source of cellulose acetate raw material is bacterial cellulose because bacterial cellulose has the higher purity and the process cost is lower rather than plant cellulose. Nowadays, the production of bacterial cellulose is highly developed using coconut water media. Nevertheless, coconut water costs expensive and the supply is rare. Materials that are being potential to be developed as raw materials of bacterial cellulose through fermentation process is palm flour liquid wasted since it contains high amounts of carbon and nitrogen. This study began with the synthesis of bacterial cellulose from palm flour oil liquid waste and coconut water using Acetobacter xylinum bacteria and then cellulose acetate is synthesized through an acetylation reaction. This study aims to determine the optimum acetylation time on its performance as a reinforcement filler to be applied as a packaging material. Based on the results of Scanning Electron Microscopy and Fourier Transform Infra-Red analysis on predetermined variables, it resulted particles in the form of bacterial cellulose and cellulose acetate with the highest yield of cellulose acetate at 3 hours of acetylation was 94.74%.

Acetylation of cellulose – Another pathway of natural cellulose aging during library storage of books and papers

Gaseous acetic acid is formed under conditions of storage of historic paper objects. Its presence not only promotes hydrolytic cleavage of cellulose, but also causes acetylation of the cellulosic material to very small degree. The acetylation reaction proceeds under ambient conditions and without catalyst. Different analytical methods were used to prove the presence of organic acetates on cellulosic paper matrices. DESI-MS in combination with 2H-isotopic labeling showed the presence of sugar fragments with different acetylation patterns. A method based on Zemplen saponification was applied and worked also in the presence of a large excess of acetic acid and/or inorganic acetates. The acetylation effect was quantified for model papers and original, naturally aged paper samples. While cellulose acetylation was clearly proven to be another general pathway of paper aging, further studies of this acetylation phenomenon are needed with regard to conservational aspects and suitable paper storage conditions.

Insights into activation of dissolving pulp preceding cellulose acetylation

The current study was conducted to identify the most important variables in the activation phase of cellulose acetate production. Dry alpha cellulose pulp as raw material was supplied by a local company with the intrinsic properties of viscosity equal to 926 mL/g and a water content of 96%. In this regard, the activation phase variables, including reaction time (T30, T60, and T90 min), the addition level of acetic acid (C25, C35, and C45 units per 100 units of dry cellulose), and sulfuric acid catalyst (H0, H0.1, H0.5, and H1%), were experimented followed by characterization of the activated pulp properties through water retention value (WRV), carboxyl groups, viscosity, reactivity, and Fourier transform infrared (FTIR) spectroscopy analysis of fibers. The results indicated that cellulose activation is a complex process with an inverse or contributing effect of the variables. The data were extensively discussed considering the swelling effects governed by diffusion and chemical reactions in both crystalline and amorphous regions of fibers. Eventually, those findings conveyed that the activation process with the above-mentioned conditions was able to improve the properties of cellulose for acetylation phase particularly by increasing reaction time in acid acetic and H2SO4 catalyst consumption.

Highly regioselective surface acetylation of cellulose and shaped cellulose constructs in the gas-phase.

Gas-phase acylation is an attractive and sustainable method for modifying the surface properties of cellulosics. However, little is known concerning the regioselectivity of the chemistry, i.e., which cellulose hydroxyls are preferentially acylated and if acylation can be restricted to the surface, preserving crystallinities/morphologies. Consequently, we reexplore simple gas-phase acetylation of modern-day cellulosic building blocks – cellulose nanocrystals, pulps, dry-jet wet spun (regenerated cellulose) fibres and a nanocellulose-based aerogel. Using advanced analytics, we show that the gas-phase acetylation is highly regioselective for the C6-OH, a finding also supported by DFT-based transition-state modelling on a crystalloid surface. This contrasts with acid- and base-catalysed liquid-phase acetylation methods, highlighting that gas-phase chemistry is much more controllable, yet with similar kinetics, to the uncatalyzed liquid-phase reactions. Furthermore, this method preserves both the native (or regenerated) crystalline structure of the cellulose and the supramolecular morphology of even delicate cellulosic constructs (nanocellulose aerogel exhibiting chiral cholesteric liquid crystalline phases). Due to the soft nature of this chemistry and an ability to finely control the kinetics, yielding highly regioselective low degree of substitution products, we are convinced this method will facilitate the rapid adoption of precisely tailored and biodegradable cellulosic materials.

Antibacterial Property of Cellulose Acetate Composite Materials Reinforced with Aluminum Nitride.

Cellulose acetate (CA) is a synthetic compound that is derived from the acetylation of cellulose. CA is well known as it has been used for many commercial products such as textiles, plastic films, and cigarette filters. In this research, antibacterial CA composites were produced by addition of aluminum nitride (AlN) at different weight percentage, from 0 wt. % to 20 wt. %. The surface characterization was performed using laser microscope, Raman and FTIR spectroscopy. The mechanical and thermal properties of the composite were analyzed. Although the mechanical strength tended to decrease as the concentration of AlN increased and needed to be optimized, the melting temperature (Tm) and glass transition temperature (Tg) showed a shift toward higher values as the AlN concentration increased leading to an improvement in thermal properties. AlN additions in weight percentages >10 wt. % led to appreciable antibacterial properties against S. epidermidis and E. coli bacteria. Antibacterial CA/AlN composites with higher thermal stability have potential applications as alternative materials for plastic packaging in the food industry.