Chitosan Schiff Base Research Articles

Fabrication of sustainable hydrogels-based chitosan Schiff base and their potential applications

Chemical modifications of chitosan were of interest to scientific researchers for its wide applications. Chitosan has been widely used for synthesis of unique compounds with potential biological activity and also effective for wastewater treatment. In the current study fabrication of new chitosan-based Schiff base hydrogels were fabricated through modification of chitosan with isonicotinic aldehyde to give hydrogel I or with epichlorohydrin or sodium tripolyphosphate via ionotropic gelation processes under the same reaction conditions to give hydrogels Ie , and nanohydrogels II, IIe respectively. FTIR, XRD, TGA, DSC, SEM, and TEM tools were used for characterization of the fabricated hydrogels I , Ie , II , and IIe hydrogels. The swelling behavior of the fabricated hydrogels in different solvents were determined. Evaluation of the hydrogels for leaching metal ions and biological activity towards different Gram-positive and Gram-negative of microorganisms were studied. The results showed that the highest efficiency for adsorption of cobalt and mercuric ions was revealed for hydrogels Ie , IIe (91.3%, 95.9%) and (92.5%, 95.9%) respectively. However, hydrogel IIe showed remarkable MIC and MBC towards Gram-positive ( B. subtilis ) (19.5, 38) μg/ml compared to the standard antibiotic Ciprofloxacin (19, 38) μg/ml respectively.

Synthesis, Characterization of Chitosan para- hydroxyl Benzaldehyde Schiff Base Linked Maleic Anhydride and the Evaluation of Its Antimicrobial Activities

Current research included preparation, characterization of some new chitosan- hydroxy benzaldehyde-Schiff bases with maleic anhydride. The present study aimed to the synthesis and characterization of novel chitosan Schiff base compounds using para- hydroxy benzaldeh and maleic anhydride. The derivative of the schiff-chitosan base, which is associated with different drugs, has been replaced with different amino and hydroxy drugs. The derivative is characterized by different analytical techniques. The results of FT-IR studies clearly indicate construction of the chief amine group in chitosan and the emergence of new bands that correspond to the association of maleic anhydride with the chitosan base. TGA, 1H-NMR, biological studies acquired two types of bacteria Gram +ve (Bacillus, Staphylococcus aureus) and two bacteria Gram -ve (Escherichia coli, Pseudomonas aeruginosa) and yeast like fungi (Candida albicans).

New chitosan Schiff base and its nanocomposite: Removal of methyl green from aqueous solution and its antibacterial activities

New chitosan Schiff base (CS-NB) and its CS-NB-NiFe nanocomposite have been prepared and characterized by FTIR spectroscopy, XRD, SEM and DSC. FT-IR spectra and XRD patterns revealed the preparation of chitosan Schiff base CS-NB and its CS-NB-NiFe nanocomposite. DSC demonstrated the endo and exothermic correspondence the evaporation of solvent and decomposition of pyranose ring, respectively. Antibacterial activities was evaluated for the as-prepared compounds against two Gram-positive (Staphylococcus aureus and Bacillus cereus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria and the results shows that the antibacterial activities of the compounds are found to be stronger than that of chitosan. The order of antibacterial effect according to inhibitory zone around is as follows: S. aureus > E. coli > B. cereus > P. aeruginosa. In addition, the removal of methyl green (MG) dye using CS-NB and its CS-NB-NiFe nanocomposite were analyzed and results showed that the compounds can be effectively used to remove of MG from aqueous solution. Results show that the percentage removal of MG by nanocomposite is higher than Schiff base.

Adsorption performance of chitosan Schiff base towards anionic dyes: Electrostatic interaction effects

In this paper, an electropositive adsorbent, salicylaldehyde-chitosan Schiff base (SCSB), was prepared via chitosan modification. The results showed that SCSB exhibited electrostatic adsorption on anionic dyes with a better adsorption performance than chitosan, corresponding to 24.75% and 79.80% removal rate of methyl orange (MO), respectively. Furthermore, the positive charge from the C = N was not strong enough to counter the electron-donating effect of salicylaldehyde, the MO removal rates of 0.5SCSB, 1.0SCSB, and 1.5SCSB were 79.80%, 69.02% and 59.60%, respectively. In the pH test, the imine group (C = N) hydrolysis showed a greater impact on charges changing than the amino group (–NH2) hydrolysis.

Applications of Chitosan Based Schiff bases and its Complexes – A Review

Chitosan, a natural polysaccharides biopolymer is a versatile and promising biomaterial. Chitosan metal complexes stand out in their applicability in different research fields due to their biocompatibility and biodegradability properties. Presence of primary aliphatic amino group along the polymer chain allows for a variety of chemical modifications, of which the most significant is imine functionalization. The ability to easily perform complexation between chitosan Schiff bases and metal ions results in metal complexes, enhancing its application, resulting in further innovation in various fields. The most recent advances of chitosan Schiff base complexes in various fields, including biomedical, catalysis, environmental, and adsorption are summarised in this review.

Fast removal of methyl green from aqueous solution by adsorption onto new modified chitosan Schiff base

New modified chitosan Schiff base (3E-2H-BCs) was prepared via a condensation reaction between 3-ethoxy-2-hydroxybenzaldehyde and chitosan. The title compound 3E-2H-BCs was characterized by various techniques such as FT-IR, UV-Vis, XRD, SEM and TG-DTA. The results show that the title compound 3E-2H-BCs was successfully prepared. In addition, the title compound 3E-2H-BCs applied as an efficient adsorbent for methyl green (MG) removal from aqueous solution and the effect of contact time and adsorbent dosage has been studied. The equilibrium of dye adsorption by 3E-2H-BCs was reached at 1 min contact time at the presence of MG. The dye adsorption results show that the title compound 3E-2H-BCs is as an efficient adsorbent for other dye removal from wastewater.

Terephthalohydrazido cross-linked chitosan hydrogels: synthesis, characterization and applications

Two new hydrogels have been synthesized by incorporating terephthalohydrazido linkages into chitosan Schiff base (TCsSB) and chitosan (TCs). They swell at pH 4 more than at pH 9 and 7. TCs has a higher activity against most of the tested microbes as indicated from its lower MIC values than that measured by the reference drugs Vancomycin and Amphotericin B. Evaluation of the cytotoxicity impacts of TCsSB and TCs revealed that they are safe on normal cells of human. Their adsorption capacity toward some heavy metal ions could be arranged as follows: Co+2 > Ni+2 > Cu+2 > Cd+2 ions.

Determination of chitosan content with Schiff base method and HPLC

Tremendous awareness of determination of chitosan content accurately is increasing, due to it has great significance to the quality control of chitosan. In this article, two kinds of chitosan-Schiff base derivatives (BCSB and PCSB) were synthesized by the different average degrees of deacetylation (DD) of chitosan with benzaldehyde or propanal, respectively. The total mass of Schiff base derivative product was dried and obtained without washing and loss. Then, a certain amount of the prepared Schiff base compound was taken to hydrolyze into glucosamine hydrochloride (GAH) in strong hydrochloric acidic environment, whose concentration was quantified by HPLC, and the mass of GAH contained in hydrolysis solution could be calculated. Subsequently, the total quality of GAH obtained by hydrolysis of all of the Schiff base product was calculated and obtained, and then the theoretical mass of chitosan could be deduced and calculated by further converse calculation. Finally, the chitosan content was obtained by combining the sample mass used in Schiff base reaction and the theoretical mass of chitosan. This method was accurate and convenient, providing a preeminent idea and method for the determination of chitosan content.

Eco-friendly chitosan Schiff base as an efficient sensor for trace anion detection

Herein, a chitosan Schiff base sample (CSAN) was strategically designed and prepared via a two-step process. In the first step, an azo derivative of 1- naphthylamine namely, [2-hydroxy-5-(naphthalene-1-yldiazenyl) benzaldehyde] (HNDB) was synthesized as an aldehyde moiety. Then the condensation reaction of HNDB with chitosan afforded CSAN as the target product. Structural analyses of synthesized material were accomplished through FT-IR, 1H NMR, UV–Vis, XRD, TGA, and SEM spectral methods. Meanwhile, the heterogeneous CSAN was able to detect the presence of hydrogen carbonate (HCO3−), acetate (AcO−), and cyanide (CN−) anions in semi-aqueous media (H2O/DMSO; 10:90%, v/v). Moreover, the selectivity of CSAN towards CN− anion was increased through variation in solvent mixture ratios. Thereupon, CSAN was explored as a promising sensor towards CN− anion in an aqueous media through considerable color variation from colorless to pale yellow as well as quantitative chemical analysis. Overall, reliable CSAN chemosensor with high sensitivity for mentioned anions has a pivotal role in practical applications owing to it’s reversibility ability.

Synthesis of new chitosan Schiff base and its Fe2O3 nanocomposite: Evaluation of methyl orange removal and antibacterial activity

New chitosan Schiff base (3EtO-4OH/Chit) and its 3EtO-4OH/Chit/Fe2O3 nanocomposite were synthesized and characterized by FTIR, 1H NMR, XRD, TGA, DSC and SEM. The result confirmed the preparation of 3EtO-4OH/Chit and its 3EtO-4OH/Chit/Fe2O3 nanocomposite. The efficiency of the prepared catalysts was studied for the methyl orange (MO) removal from aqueous solution. The effect of adsorbent dose and contact time on the removal of dye has been studied. Their antibacterial activities were considered against two Gram positive (S. aureus and B. cereus) and two Gram negative (E. coli and P. aeruginosa) bacteria and the results showed that the activity of the 3EtO-4OH/Chit/Fe2O3 is excellent and is more than chitosan and 3EtO-4OH/Chit. Thermogravimetry studies shows that the weight loss stages and the residual value at 600 °C are different for the two compounds. DSC curve of the title compounds 3EtO-4OH/Chit and 3EtO-4OH/Chit/Fe2O3 is different from each other. The reason for this difference could be due to the presence of iron oxide nanoparticles in 3EtO-4OH/Chit/Fe2O3.

Thermal Stability, Kinetic Degradation and Lifetime Prediction of Chitosan Schiff Bases Derived from Aromatic Aldehydes

AbstractThis study intends to synthesis chitosan‐aromatic aldehyde Schiff bases (ChSB) to investigate their thermal stability and kinetics degradation. All samples were characterized by FTIR, XRD and SEM techniques. Chitosan and chitosan derivatives were subjected to thermo‐gravimetric analysis, at four multiple heating rates 5, 10, 15 and 20 °C.min−1. Calculations using two isoconversional integral methods, Flynn Wall Ozawa and Kissinger were performed. The changes in Entropy, Enthalpy, Gibbs free energy, and lifetime have been estimated. Thus, chitosan modification with aromatic aldehydes would have an accelerating effect on thermal decomposition. In addition, chitosan p‐chlorobenzaldehyde were found to have the relative highest activation energy and the highest lifetime to thermally decompose amongst the other examined biopolymers. The kinetic process for the degradation of pure chitosan, chitosan‐N,N‐dimethylaminobenzaldehyde and chitosan‐p‐chlorobenzaldehyde was most probably described by an exponential function E1.While for chitosan‐p‐methoxybenzoaldehyde the function D12 corresponding to a mechanism coupling “transfer and diffusion” seems to describe the degradation.

Motivating and Supporting Undergraduate Research through Green Chemistry: Experiences at a Small Liberal Arts University

Although most instructors and institutions agree on its value, undergraduate research remains an underutilized pedagogical tool because it requires ample time, funding, and equipment. Various institutions feel these pressures differently, but for many small institutions, lack of laboratory equipment and financial support can hinder undergraduate research projects. However, these institutions have much to gain from undergraduate research, especially as it offers benefits not only for students but also for faculty. For small institutions, although the principle applies to larger institutions as well, green chemistry offers a promising way forward: undergraduate research projects focusing on green chemistry have all the benefits of other undergraduate research projects but can be undertaken with minimal infrastructure and reduced cost. As an added benefit, they can help to reinforce the values of safety and sustainability for future chemists. This paper offers an example of a successful undergraduate research project in chemistry in a small liberal arts university and demonstrates how a project in green chemistry can make research-based learning feasible even in institutions with limited resources. Specifically, this project focuses on the development of a bioinspired, environmentally friendly wound-care product derived from chitosan and two naturally occurring aldehydes, citronellal and cinnamaldehyde. In this project, the student researcher prepared two chitosan Schiff bases using citronellal and cinnamaldehyde and then characterized and evaluated the antimicrobial properties of these products. Results suggest that both Schiff bases are highly bioactive and could indeed have value in wound-care. This project has scientific benefit, of course, but it also has pedagogical merits, showing how green chemistry can enable institutions to offer valuable undergraduate research opportunities with limited funding and infrastructure. This paper concludes with suggestions for related (and feasible) undergraduate research projects in green chemistry.

Fabrication of a novel chitosan Schiff bases hydrogel derivatives for the removal of anionic dyes from wastewater

Fabrication of a novel chitosan Schiff bases hydrogel derivatives for the removal of anionic dyes from wastewater

Methyl orange dye removal from wastewater by novel developed chitosan Schiff bases

Methyl orange dye removal from wastewater by novel developed chitosan Schiff bases

A cross-linked chitosan-Schiff base: new material for the removal of methyl orange from aqueous solution

A cross-linked chitosan-Schiff base: new material for the removal of methyl orange from aqueous solution

Isolation of essential oil from lauraceous leaves and Schiff’s reaction based cinnamaldehyde derivatization

The barks of Cinnamomum species found to contain essential oil, namely, Cinnamomum zeylanicum, C. camphora, C. tamala etcetra. The major component is Cinnamaldehyde. Essential oils from leaves of Lauraceae family have not yet been isolated. It was therefore thought to isolate essential oils from leaves of mentioned species and check presence of Cinnamaldehyde presence. It was found that Cinnaldehyde is found only in C. zeylanicum. At same time, as Cinnamaldehyde is a chief constituent present in Cinnamomum species; it was observed that Cinnamaldehyde has been derivatized to make Schiff’s bases for very few compounds. For example, Cinnamyl chitosan Schiff base was prepared by coupling chitosan with trans-Cinnamaldehyde -the mean component of cinnamon oil- under acidic conditions to form cinnamyl chitosan Schiff base. Therefore, it was further thought worthwhile to derivatise Cinnamldehyde with available Substituted amines available in the local market followed by physical characterization. Keywords: Cinnamomum zeylanicum, C. camphora, C. tamala, Cinnamaldehyde, Essential oils, Clevenger Apparatus, LC-MS, Schiff’s bases.

In VitroEvaluation of Antifungal Activities by Permeation of Ru(III) Complexes Derived from Chitosan-Schiff Base Ligand

Background:The transition metal complexes are derived from a natural biopolymer which is a very potent material in various research areas of study.Objective:This study aims to show the preparation of ruthenium(III) complexes from chitosan Schiff base ligand for effective application in antifungal studies.Methods:Chemical modification was carried out through a condensation reaction of chitosan with some aromatic aldehydes, which resulted in the formation of a bidentate Schiff base ligand. The Ru(III) complexes were prepared by complexation of ruthenium metal ion with bidentate ligands. The series of Ru(III) complexes were characterized by Scanning Electron Microscope with Electron dispersive X-ray (SEM-EDX) analysis, Powder XRD. The biopolymer-based transition metal complexes have potential uses for their biological activities. The synthesized metal complexes were directed for antifungal study by the disc diffusion method.Results:The antifungal study results showed that the transition metal complexes have significant antifungal activities against some vital fungal pathogens such as Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Penicillim chryogenum and Trigoderma veride.Conclusion:A chitosan biopolymer offers some peculiar features such as biodegradability, biocompatibility etc., which are favorable for green synthesis of transition metal complexes through complexation with bidentate ligands. These metal complexes possess good antifungal property due to their chelation effect on micro-organisms.

The Electrical Conductivty Of Fe-Chitosan Schiff Base Complex

High electrical conductivity material Fe-Chitosan Schiff base produced via two stages mechanism, reaction of salicylaldehyde and chitosan in three necked flask following the formation of complex by soak Chitosan Schiff base in FeCl3 solution in various times. The formed Schiff base was confirmed by presence of imine at 1604.77 cm-1. Next, Fe absorption was analyzed by using ICP-MS gives highest results at 492,51 ppm at 5 hours immersion time. The electrical conductivity exhibit tendency to increase and the highest point at 3.5 x 10-6 S cm­-1

Synthesis and Characterization of O-(carboxyl) Chitosan Schiff Base Derivatives and Study Antibacterial Activity

2-mercaptobenzothiazol [1] was reacted with anhydrous carbonate sodium and ClCH2COOH in distilled water to produce a compound [2]. Compound [3] was synthesized by reaction compound [2] with SOCl2 in benzene. O,N-chitosan derivative [4] had synthesized by reacted chitosan with compound [3] in trichloromethane and pyridine. O-chitosan derivative synthesized according to the method of Fischer and Speier from the reaction of chitosan with compound [2] in distilled water in acidic media to produce compound [5]. O-(carboxyl) chitosan Schiff base derivatives [6-9] had synthesized by reaction O-(carboxyl) chitosan [5] with aromatic aldehydes (syringaldehyde, 3-methoxy,4-hydroxybenzeldehyde, 4-nitrobenzeldehyde, 4-bromobenzeldehyde). The structure of produced compounds has been characterized through their spectral and analytical data, as in fourier transform infrared (FTIR) spectra,1H-NMR, UV-vis spectroscopy, elemental analysis (CHNS), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and thermo gravimetry analysis (TGA). Finally, study the antibacterial activity of some prepared polymers.

Synthesis and Biological Evaluation of Three New Chitosan Schiff Base Derivatives.

Recently, chemical modifications of chitosan (CS) have attracted the attention of scientific researchers due to its wide range of applications. In this research, chitin (CH) was extracted from the scales of Cyprinus carpio fish and converted to CS by three chemical steps: (i) demineralization, (ii) deprotonation, and (iii) deacetylation. The degree (measured as a percentage) of deacetylation (DD %) was calculated utilizing the acid–base titration method. The structure of CS was characterized by Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Three new CS Schiff bases (CSSBs) (CS-P1, CS-P2, and CS-P3) were synthesized via coupling of CS with 2-chloroquinoline-3-carbaldehyde, quinazoline-6-carbaldehyde, and oxazole-4-carbaldehyde, respectively. The newly prepared derivatives were verified, structurally, by nuclear magnetic resonance (1H and 13C NMR) and FT-IR spectroscopy. Antimicrobial activity was evaluated for the prepared compounds against both “Gram-negative” and “Gram-positive” bacteria, namely, Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and Streptococcus mutans, in addition to two kinds of fungi, Candida albicans and Aspergillus fumigates. Cytotoxicity of the synthesized CSSBs was evaluated via a MTT screening test. The results indicated a critical activity increase of the synthesized compound rather than CS generally tested bacteria and fungi and the absence of cytotoxic activity. These findings suggested that these new CSSBs are novel biomaterial candidates with enhanced antibacterial and nontoxic characteristics for applications in areas of both biology and medicine.