Esterification of cellulose with betaine using p-toluenesulfonyl chloride for the in-situ activation of betaine

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7592-7607
Author(s):  
Yu Liu ◽  
Fangfang Wang ◽  
Yangyang Sun
Keyword(s):  
Synthesis Method ◽  
Degree Of Polymerization ◽  
Degree Of Substitution ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Cellulose Ester ◽  
Cellulose Esters ◽  
In Situ Activation ◽  
Modified Cellulose

A novel synthesis method was developed for betaine-modified cellulose ester using a mixed N,N-dimethylacetamide/lithium chloride solvent system; p-toluenesulfonyl chloride was used for the in-situ activation of the betaine. The influence of the reaction temperature and time, as well as the anhydroglucose unit to p-toluenesulfonyl chloride to betaine mass ratio on the degree of substitution of the product was evaluated. Increasing the proportion of betaine and p-toluenesulfonyl chloride was beneficial to the esterification reaction. The degree of substitution was 1.68 at 90 °C for 32 h with an anhydroglucose unit to p-toluenesulfonyl chloride to betaine molar ratio of 1 to 2 to 3. The physicochemical properties of the betaine-modified cellulose were closely related to the degree of substitution. Major changes in the morphologies, crystallinity, thermal properties, porosity, and the average degree of polymerization resulted from the modification. The introduction of betaine made cellulose esters thermally less stable than neat cellulose but more difficult to completely degrade. The crystalline structure of the cellulose esters was destroyed, and the products exhibited a porous nature. Dye sorption studies demonstrated that the betaine-modified cellulose holds the potential of adsorbing anionic substances, which is the premise of its application.

Preparation and characterization of cellulose bromo-isobutyl ester based on filter paper

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rina Wu ◽  
Qiuyu Wang ◽  
Huayu Liu ◽  
Gaosheng Wang ◽  
Peng Lu
Keyword(s):  
Filter Paper ◽  
Food Packaging ◽  
Degree Of Substitution ◽  
Raw Material ◽  
Esterification Reaction ◽  
Dimethyl Formamide ◽  
Cellulose Ester ◽  
Cellulose Esters ◽  
Simple Method ◽  
Isobutyl Ester

AbstractCellulose bromo-isobutyl ester was prepared using filter paper as raw material through esterification reaction with 2-Bromoisobutyryl bromide (BIBB) in N, N-Dimethyl-formamide (DMF). Cellulose esters with different degree of substitution were obtained. FTIR result indicated the successful introduction of bromo isobutyryl group in cellulose to obtain cellulose ester (Cell-Br). The surface of modified filter paper become rough and grooves could be observed by SEM. The thermal stability of the cellulose ester decreased in comparison with unmodified filter paper. Besides, the hydrophobicity of the filter paper was improved and the water contact angle increased from 73.4° to 116.5° with increasing degree of substitution. The water vapor barrier property was improved by 26 %. Furthermore, it was also found the modified filter paper possessed antibacterial activity against S. aureus bacteria. The modified filter paper obtained could be potentially used in food packaging fields and the results provide a simple method to prepare functional filter paper.

Cellulose-Ester as Membrane Materials for Hemodialysis

1994 ◽  
Vol 17 (7) ◽  
pp. 385-391 ◽  
Author(s):  
M. Diamantoglou ◽  
H.D. Lemke ◽  
J. Vienken
Keyword(s):  
Blood Compatibility ◽  
Degree Of Substitution ◽  
Cellulose Ester ◽  
Regenerated Cellulose ◽  
Special Focus ◽  
Standard Type ◽  
Cellulose Esters ◽  
Recent Developments ◽  
Cellulosic Membrane ◽  
Chain Lengths

The majority of dialysis membranes are fabricated from regenerated unmodified cellulose. This standard type of cellulosic membrane is frequently under attack because of its alleged lack of biocompatibility. Recent developments, however, have proven that a chemical modification of the reactive surface groups of regenerated cellulose, the hydroxylgroups, limits the complement-activating potential of these materials and thus improves its blood-compatibility. We extended the idea of modifying cellulose for improved blood-compatibility to a series of different cellulose esters. Special focus was directed towards the question whether a variation of the type of substituent and degree of substitution could influence the blood-compatibility pattern of these materials: the analysis of blood-compatibility profiles showed a direct dependency on the type of substituent and the degree of substitution (DS). As an example, it was found that the DS, necessary for a complete reduction of complement activation, decreases with increasing chain lengths of aliphatic substituents. Optimal degrees of substitution are characteristic of the type of substituents and enable us to tailor materials specifically for optimized blood compatibility.

A Novel Route for Conversion of Free Fatty Acids in Acidic Oils to Methyl Esters by In-Situ Hydrolysis of Methyl Acetate

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Vijaya Lakshmi Ch ◽  
Uday Bhaskar R.V.S ◽  
Viswanath Kotra ◽  
Satyavathi Bankupalli
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Methyl Acetate ◽  
Edible Oils ◽  
Methyl Esters ◽  
Maximum Yield ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Higher Alcohol

Biodiesel from clean oils is comparatively easier than production from crude and non-edible oils. To achieve maximum yield of biodiesel, a two stage process is adopted in which non-edible oils are used as feed-stock: an acid catalyzed esterification of free fatty acids followed by base catalyzed transesterification. Presence of water formed during esterification reaction is detrimental to a viable transesterification process. In the present work, an alternate method for removal of water by in situ hydrolysis reaction of methyl acetate is introduced. The dehydration using methyl acetate during esterification has yielded good results as the soap formed during transesterification was minimal. The results indicated high conversion of triglycerides to methyl ester for lower oil to methanol ratio and at a lower temperature. For 1:3 molar ratio of oil to methanol, the conversion obtained was less than 90 percent and is equivalent to conversions with higher alcohol ratios during esterification in the absence of methyl acetate. These results are indicative of the fact that use of methyl acetate reduces the alcohol to oil ratio without affecting the conversions. Moreover, higher conversions are possible at lower temperatures in the presence of methyl acetate. It is further observed that the oils that are subjected to free fatty acid conversions in the presence of methyl acetate record very little soap formation during the transesterification reactions, thereby resulting in higher grade of biodiesel.

In Situ Synthesis of Copper Phthalocyanine Modified Multiwalled Carbon Tube and its Electrocatalytic Application towards the Oxidation of Nitrite

2014 ◽  
Vol 938 ◽  
pp. 40-45 ◽  
Author(s):  
K.N. Porchelvi ◽  
S. Meenakshi ◽  
Kanniyan Pandian
Keyword(s):  
Copper Phthalocyanine ◽  
Solid Phase ◽  
Synthesis Method ◽  
Food Samples ◽  
Ammonium Molybdate ◽  
Molar Ratio ◽  
Metal Phthalocyanine ◽  
X Ray Diffraction ◽  
Multiwalled Carbon

We have synthesized metal phthalocyanine modified multiwalled carbon nanotube by a solid-phase synthesis method by heating a reaction mixture of phthalic anhydride, ammonium molybdate and MWCNT in a required molar ratio using muffle furnace. The metal phthalocyanine modified MWCNT samples collected and then washed extensively with various solvents to removal all impurities and unreacted starting materials. The resulting nanocomposite was characterized by IR, UV-Visible spectroscopy, Scanning Electron Microscopy, X-ray diffraction and Raman spectroscopy. The nanostructure of the CuPc/MWCNT assembly exhibits a homogeneous nanocomposite. The electrocatalytic study of the CuPc/MWCNT assembly towards the oxidation of nitrite was investigated. An enhanced oxidation peak current was noted with lowering oxidation over potential ranges. The proposed method can be applied for the amperometry detection of nitrite present in food samples.

Methane Steam Reforming Over NiO/CexZryO2-Sil-1 Catalyst Prepared by In-Situ Self-Assembly

2019 ◽  
Vol 19 (11) ◽  
pp. 7416-7420
Author(s):  
Ning Wei ◽  
Jia Zhang ◽  
Hexiang Zhong ◽  
Liwei Pan ◽  
Zeyu Wang ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Steam Reforming ◽  
Self Assembly ◽  
Methane Conversion ◽  
High Surface ◽  
Synthesis Method ◽  
Methane Steam Reforming ◽  
Molar Ratio ◽  
Methane Steam

NiO/CexZryO2-Sil-1 catalysts were prepared using an In-Situ self-assembly approach by coupling silicalite-1 and CexZryO2. This one-step synthesis method utilized the high surface area and hydrothermal stability of silicalite-1 and the good oxidation-reduction ability of the CexZryO2, and hence offered high synthesis efficiency. The catalyst structure was examined by N2-physisorption, temperature-programmed reduction, transmission electron microscopy, and X-ray diffraction. All the results showed that silicalite-1 was well-encapsulated by NiO/Ce0.5Zr0.5O2. Furthermore, the effect of the Ce/Zr molar ratio on the performance of the catalysts was investigated in detail. The catalysts were subjected to methane steam reforming at high temperatures to evaluate their catalytic performance. The result showed that the NiO/Ce0.5Zr0.5O2-Sil-1 catalyst exhibited the best performance and its methane conversion efficiency reached up to 99.5%. Even after 16 h of continuous stability test, this catalyst could retain a methane conversion efficiency of 97.8%.

A Photoactivatable α5β1-Specific Integrin Ligand

2018 ◽  
Author(s):  
Roshna Vakkeel ◽  
Aleeza Farrukh ◽  
Aranzazu del Campo
Keyword(s):  
Cellular Response ◽  
Light Exposure ◽  
Matrix Composition ◽  
Cellular Behavior ◽  
Dynamic Variations ◽  
In Situ Activation ◽  
Controlled Exposure ◽  
Cellular Behaviour ◽  
Integrin Ligand

In order to study how dynamic changes of α5β1 integrin engagement affect cellular behaviour, photoactivatable derivatives of α5β1 specific ligands are presented in this article. The presence of the photoremovable protecting group (PRPG) introduced at a relevant position for integrin recognition, temporally inhibits ligand bioactivity. Light exposure at cell-compatible dose efficiently cleaves the PRPG and restores functionality. Selective cell response (attachment, spreading, migration) to the activated ligand on the surface is achieved upon controlled exposure. Spatial and temporal control of the cellular response is demonstrated, including the possibility to in situ activation. Photoactivatable integrin-selective ligands in model microenvironments will allow the study of cellular behavior in response to changes in the activation of individual integrins as consequence of dynamic variations of matrix composition.

scholarly journals One-step synthesis of nitrogen-grafted copper-gallic acid for enhanced methylene blue removal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shella Permatasari Santoso ◽  
Vania Bundjaja ◽  
Artik Elisa Angkawijaya ◽  
Chintya Gunarto ◽  
Alchris Woo Go ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Gallic Acid ◽  
Synthesis Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
One Step ◽  
Detailed Assessment ◽  
Higher Temperature

AbstractNitrogen-grafting through the addition of glycine (Gly) was performed on a metal- phenolic network (MPN) of copper (Cu2+) and gallic acid (GA) to increase its adsorption capacity. Herein, we reported a one-step synthesis method of MPN, which was developed according to the metal–ligand complexation principle. The nitrogen grafted CuGA (Ng-CuGA) MPN was obtained by reacting Cu2+, GA, and Gly in an aqueous solution at a molar ratio of 1:1:1 and a pH of 8. Several physicochemical measurements, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), N2 sorption, X-ray diffraction (XRD), and thermal gravimetry analysis (TGA), were done on Ng-CuGA to elucidate its characteristics. The analysis revealed that the Ng-CuGA has non-uniform spherical shaped morphology with a pore volume of 0.56 cc/g, a pore size of 23.25 nm, and thermal stability up to 205 °C. The applicational potential of the Ng-CuGA was determined based on its adsorption capacity against methylene blue (MB). The Ng-CuGA was able to adsorb 190.81 mg MB per g adsorbent at a pH of 6 and temperature of 30 °C, which is 1.53 times higher than the non-grafted CuGA. Detailed assessment of Ng-CuGA adsorption properties revealed their pH- and temperature-dependent nature. The adsorption capacity and affinity were found to decrease at a higher temperature, demonstrating the exothermic adsorption behavior.

Comparative study of MoS2 and Co/MoS2 catalysts prepared by ex situ/in situ activation of ammonium and tetraalkylammonium thiomolybdates

2004 ◽  
Vol 210 (1-2) ◽  
pp. 105-117 ◽  
Author(s):  
L. Alvarez ◽  
J. Espino ◽  
C. Ornelas ◽  
J.L. Rico ◽  
M.T. Cortez ◽  
...  
Keyword(s):  
Comparative Study ◽  
Ex Situ ◽  
In Situ Activation ◽  
Mos2 Catalysts

Study on the Synthesis of Isoamyl Acetate Catalyzed by Strong Acidic Cation Exchange Resin

2011 ◽  
Vol 396-398 ◽  
pp. 2411-2415 ◽  
Author(s):  
Ping Lan ◽  
Li Hong Lan ◽  
Tao Xie ◽  
An Ping Liao
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Cation Exchanger ◽  
Cation Exchange Resin ◽  
Isoamyl Acetate ◽  
Molar Ratio ◽  
Esterification Reaction ◽  
Reaction Conditions ◽  
Optimum Reaction

Isoamyl acetate was synthesized from isoamylol and glacial acetic acid with strong acidic cation exchanger as catalyst. The effects of reaction conditions such as acid-alcohol ratio, reaction time, catalyst dosage to esterification reaction have been investigated and the optimum reaction conditions can be concluded as: the molar ratio of acetic acid to isoamylol 0.8:1, reaction time 2h, 25 % of catalyst (quality of acetic acid as benchmark). The conversion rate can reach up to 75.46%. The catalytic ability didn’t reduce significantly after reusing 10 times and the results showed that the catalyst exhibited preferably catalytic activity and reusability.

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