Distortionless Enhancement By Polarization Transfer Research Articles

Asphaltenes Precipitated by a Two-Step Precipitation Procedure. 2. Physical and Chemical Characteristics

In a previous study (10.1021/ef060311g), a two-step precipitation procedure for asphaltenes from three crude oils (WA, NS-A, and NS-B) was reported. Crude oils were diluted 3:1 with n-pentane, and precipitated asphaltenes were filtrated off (first fraction). A second fraction consisting of asphaltenes still present in the crude oil was precipitated by further dilution of 18:1 n-pentane/crude oil. In the previous work, interfacial tension, aggregation size, and onset of precipitation were investigated and shown. In the current work, elemental analysis indicated that the first fractions contain relatively more heteroatoms than the second fractions and whole asphaltenes. Fourier transform infrared (FTIR) spectroscopy, proton and carbon nuclear magnetic resonance (NMR) spectroscopy, and NMR–distortionless enhancement by polarization transfer (DEPT) indicated that the less soluble fractions WA and NS-B were more aromatic and had a more polar aromatic core and a larger aromatic core consisting of more rings. Fu...

Characterization of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) prepared from natural rubber through 2D NMR spectroscopy

AbstractPoly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) was prepared by epoxidation of deproteinized natural rubber with m‐chloroperbenzoic acid followed by hydrolysis with sulfuric acid. Characterization of the resulting product was performed through FT‐IR, 1H NMR, and 13C NMR spectroscopies. All signals appearing in the 1H and 13C NMR spectra were assigned by distortionless enhancement by polarization transfer (DEPT), quaternary carbon observation (QUAT), correlation spectroscopy (COSY), and heteronuclear multiple quantum correlation (HMQC) measurements. After proving the primary structure of the product, one pot synthesis of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) from deproteinized natural rubber latex was carried out with peracetic acid and 2‐propanol. The resulting product was characterized by 1H NMR spectroscopy on the basis of the assignments established in this study, and its gas permeability was measured for a practical application as a film. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

ANTIMICROBIAL AND ANTIHYPERLIPIDEMIC ACTIVITIES OF ISOLATED QUERCETIN FROM ANABAENA AEQUALIS(1).

This study aimed to isolate quercetin (for the first time) from Anabaena aequalis Borge, which inhabits soil surface of Wadi El-Alaqui Protectorate located in Aswan city, Egypt. The isolated compound showed significant antibacterial activity against the gram-positive bacteria Sarcina maxima and Micrococcus kristinae, the gram-negative bacterium Klebsiella pneumoniae, as well as against the filamentous fungus Aspergillus flavus. The isolated compound was identified as quercetin using the structure elucidation based on UV, electrospray ionization mass spectrometry (ESIMS), (1) H and (13) C NMR, proton-proton correlation spectroscopy ((1) H-(1) H COSY), distortionless enhancement by polarization transfer (DEPT), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlations spectrum (HMBC). Medium lethal dose (LD50 ) of the isolated compound and its side effects against hyperlipidemia induced by ethanol intake in albino rats were carried out. No deaths were reported in rats within 72 h, which suggests that the isolated compound plays a beneficial role as an antihyperlipidemic agent in the treatment of alcohol-induced hepatic tissue damage, which can be described as one of the therapeutic values.

Purification and Properties of a Novel Phenolic Antioxidant from Radix astragali Fermented by Aspergillus oryzae M29

The Chinese herb Radix astragalus (RA) has been widely used as a dietary supplement in Asia, and there are numerous reports on its bioactivities. However, there are no reports to date regarding the use of Aspergillus spp. in the culture medium of the RA plant for the production of phenolic antioxidants. In this study, utilizing the fungus Aspergillus to ferment the native RA has successfully resulted in a significant increase in the phenolic contents of RA, and the fermented RA also revealed much better antioxidant activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, hydroxyl radical, superoxide radical and peroxyl radical than those of unfermented RA. Among these phenolics, a potent novel antioxidant was isolated and identified as 3,4-di(4'-hydroxyphenyl) isobutyric acid with a molecular weight of 272, by ESI-MS (electrospray ionization mass), ¹H NMR (nuclear magnetic resonance), ¹³C NMR, DEPT (distortionless enhancement by polarization transfer)-NMR, HMQC (heteronuclear multiple quantum coherence), and HMBC (heteronuclear multiple bond correlation) spectra. These data demonstrated that the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of RA.

Synthesis, electrochemical and structural characterization of novel azacrown ether containing macrocyclic redox-active vic-dioxime ligand and its mononuclear transition metal complexes: Application of DEPT, HSQC, HMBC-NMR and cyclic voltammetry

This paper presents a new azacrown containing vic-dioxime; anti-N-(4-aminophenyl)aza-15-crown-5-glyoxime (LH 2), and its mononuclear nickel(II), copper(II), cobalt(II), cadmium(II) and zinc(II) complexes. The azacrown moieties appended at the periphery of the oxime provide solubility for the vic-dioxime ligand and complexes in common organic solvents. The mononuclear M(LH) 2 (M = Ni and Cu), M(LH) 2(H 2O) 2 (M = Co) and [M(LH)(H 2O)(Cl)] (M = Cd and Zn) complexes have been obtained with the metal:ligand ratios of 1:2 and 1:1. The structure of the ligand is confirmed by elemental analysis, Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), mass spectrometry (MS), one-dimensional (1D) 1H, 13C NMR, distortionless enhancement by polarization transfer (DEPT) and two-dimensional (2D) heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) techniques. The structures of the complexes are confirmed by elemental analyses, MS, UV–Vis, FT-IR and 1H, 13C NMR techniques. Redox behaviors of the ligand and its complexes have been investigated by cyclic voltammetry at the glassy carbon electrode in 0.1 M TBATFB in DMSO. The antibacterial activity was studied against Staphylococcus aureus ATCC 29213, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Lactobacillus acidophilus RSHM 06029, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The antimicrobial test results indicate that all the complexes have low levels of antibacterial activity against both Gram negative and Gram positive bacterial species.

高分解能｀１３´Ｃ‐ＮＭＲ法によるクロロプレンゴムの構造解析

Signals in 13C-NMR spectrum for polychloroprene were re-assigned through 1D and 2D NMR spectroscopy, that is, distortionless enhancement by polarization transfer (DEPT), heteronuclear multiple quantum correlation (HMQC), and heteronuclear multiple bond correlation (HMBC) measurements. The unknown signals at 40.1, 43.0, 45.5, 128.4, 129.1, and 130.1 ppm in 13C-NMR spectrum for raw chloroprene rubber were assigned to secondary carbon of 1,2 unit, secondary carbon of 1,4 unit adjacent to 3,4 unit, tertiary carbon of 3,4 unit, tertiary carbon of 1,4 unit adjacent to 3,4 unit, quaternary carbon of 1,4 unit adjacent to 1,2 unit, and tertiary carbon of 1,4 unit adjacent to 1,2 unit, respectively. The resulting information on the assignments was used for characterization of chloroprene rubber vulcanizate and aged chloroprene rubber vulcanizate.

Characterization of Chemical Constituents of <i>Luffa operculata</i>(Cucurbitaceae)

A mixture of new ceramides (1, 2, 3, 4 and 5) together with a binary mixture of ceramides with long chain alkyl (6 and 7), triterpenoid (10) and steroids (11 and 12) have been isolated from bark of the fruits and of the stems of Luffa operculata (Cucurbitaceae). The structures were elucidated by comprehensive spectro- scopic analysis including 1H and 13C NMR, DEPT (distortionless enhancement by polarization transfer), COSY (correlated spectroscopy), HMQC (heteronuclear multiple quantum coherence), HMBC (heteronu- clear multiple bond connectivity), IR (infrared), HR-ESI-MS (electrospray ionization-high resolution mass spectra) and LR-MS (low resolution electron ionization mass spectra) experiments. All the ceramides are reported for the first time in Cucurbitaceae and this is the first report of the rare triterpene 10 isolated from Luffa operculata. The ceramides 6 and 7 showed a high acetylcholine esterase inhibitory effect.

Polymerization of 4-methyl-1-pentene catalyzed by α-diimine nickel catalysts: Living/controlled behavior, branch structure, and mechanism

Branched α-olefin, 4-methyl-1-pentene (4 MP), was polymerized with classical α-diimine nickel complexes in the presence of MAO. Influences of structure of α-diimine nickel catalysts and polymerization parameters including temperature and [Al]/[Ni] mole ratio were evaluated. At 0 °C, 4-methyl-1-pentene can be polymerized in a living/controlled manner. The obtained poly(4-methyl-1-pentene)s are amorphous elastomers with low glass transition temperature (Tg). Nuclear magnetic resonance (NMR) and distortionless enhancement by polarization transfer (DEPT) analyses show that various types of branches and microstructural units are present in the polymers. On the basis of assignment of microstructures, mechanistic models that involves the 1,2- and 2,1-insertion, and chain walking were constructed. The influences of temperature and [Al]/[Ni] mole ratio on branching degree, branch type, and insertion pathways were also discussed in detail.

Isolation of β-(1-3) Glucan Compound from the Water Extract of Indonesian Jamur Tanduk (Termitomyces eurirrhizus Berk)

Jamur Tanduk (Termitomyces eurirrhizus Berk) is one of uncultivated edible mushrooms from genus Termitomyces found in various regions in Indonesia. The purpose of this study is to analyze the chemical structure of its beta-glucan compound that possesses bioactivity as lowering cholesterol levels. Isolation and identification of beta-glucan compound from water extract of Jamur tanduk (local name), Termitomyces eurirrhizus Berk collected in Sumedang has been done. beta-glucan was isolated with Wasterlund methods and obtained as white powder. Isolated compound was identified based on interpretation of spectroscopies data such as Ultra-Violet (UV), Infra-Red (IR) and nuclear magnetic resonance one dimensional such as 1Hidrogen-Nuclear Magnetic Resonance (1H-NMR), 13Carbon- 13C-NMR) and Distortionless Enhancement by Polarization Transfer (DEPT) and two dimensional such as Correlation spectroscopy (COSY), Hetero Multiple Quantum Connectivity (HMQC) and Hetero Multiple Bond Connectivity (HMBC). The determination of molecule weight of sample based on viscosity measurements and obtained that beta-glucan has 322 molecules of glucose.

Performance Evaluation of Quantitative Adiabatic 13C NMR Pulse Sequences for Site-Specific Isotopic Measurements

(2)H/(1)H and (13)C/(12)C site-specific isotope ratios determined by NMR spectroscopy may be used to discriminate pharmaceutically active ingredients based on the synthetic process used in production. Extending the Site-specific Natural Isotope Fractionation NMR (SNIF-NMR) method to (13)C is highly beneficial for complex organic molecules when measurements of (2)H/(1)H ratios lead to poorly defined molecular fingerprints. The current NMR methodology to determine (13)C/(12)C site-specific isotope ratios suffers from poor sensitivity and long experimental times. In this work, several NMR pulse sequences based on polarization transfer were evaluated and optimized to measure precise quantitative (13)C NMR spectra within a short time. Adiabatic 180 degrees (1)H and (13)C pulses were incorporated into distortionless enhancement by polarization transfer (DEPT) and refocused insensitive nuclei enhanced by polarization transfer (INEPT) to minimize the influence of 180 degrees pulse imperfections and of off-resonance effects on the precision of the measured (13)C peak areas. The adiabatic DEPT sequence was applied to draw up a precise site-specific (13)C isotope profile of ibuprofen. A modified heteronuclear cross-polarization (HCP) experiment featuring (1)H and (13)C spin-locks with adiabatic 180 degrees pulses is also introduced. This sequence enables efficient magnetization transfer across a wide (13)C frequency range although not enough for an application in quantitative (13)C isotopic analysis.

DFT Calculations of Indirect 29Si−1H Spin−Spin Coupling Constants in Organoalkoxysilanes

The performance of four basis sets (6-311+G(2d,p), IGLO-III, cc-PVTZ, and 6-31G) is evaluated in order to find a quantum mechanical technique that can be used to accurately estimate (29)Si-(1)H spin-spin coupling constants in organoalkoxysilanes. The 6-31G basis set with the B3LYP functional is found to be an accurate, efficient, and cost-effective density functional theory method for predicting spin-spin coupling constants of organoalkoxysilanes. Knowledge of these scalar coupling constants and their dependence on structural variations is important to be able to fine-tune NMR experiments that rely on polarization transfer among nuclei, such as (29)Si distortionless enhancement by polarization transfer (DEPT). The effects of size and the number of unhydrolyzable alkyl groups attached to silicon and the effects of substitution of alkoxy groups with hydroxyl groups on (29)Si-(1)H spin-spin coupling constants are investigated using this DFT method. The results show that the predicted scalar coupling between silicon and organic groups depends weakly on the degree of hydrolysis of the alkoxysilanes. The effectiveness of this method is also illustrated for the determination of spin-spin coupling constants in a species containing a siloxane bond.

Product operator descriptions of the 2D DEPT J-resolved NMR experiment for weakly coupled ISn (, ; n=1, 2, 3) spin systems

There are a variety of multi-pulse nuclear magnetic resonance (NMR) experiments for spectral assignment of complex molecules in a solution. The two-dimensional (2D) distortionless enhancement by polarization transfer (DEPT) J-resolved NMR experiment is a 13C-detected, spectral editing polarization transfer technique. The product operator theory is widely used for an analytical description of the multi-pulse NMR experiment for weakly coupled spin systems. In this study, analytical descriptions of the 2D DEPT J-resolved NMR experiment for weakly coupled ISn (, ; n=1, 2, 3) spin systems using the product operator theory have been introduced for the first time. The calculated intensities and positions of the observable signals are simulated for molecules containing [13C , 81Br )] nuclei by using a MAPLE program on a computer. Finally, we present a theoretical discussion and experimental suggestions.

In vitro Anti-Leishmanial and Anti-Tumour Activities of a Pentacyclic Triterpenoid Compound Isolated from the Fruits of Dregea volubilis Benth Asclepiadaceae

Purpose: Dregea volubilis Benth, commonly known as Jukti in Bengal, is used in the treatment of boils and abscesses from ancient times. The purpose of this study is to elucidate the active compounds and as well as their anti-leishmanial and anti-tumour activities. Methods: Dried and crushed fruits of Dregea volubilis were extracted by petroleum ether (40 - 60°C); the best solvent system had first been verified by analytical Thin Layer Chromatography (TLC). The extract was subjected to TLC and column chromatography (CC) to isolate the pure compounds. Spectra data were obtained by Infra Red pectroscopy, Mass Spectroscopy and Nuclear Magnetic Resonance - Proton Magnetic Resonance (PMR), Carbon Magnetic Resonance (CMR) and Distortionless Enhancement by Polarization Transfer (DEPT) - for structure elucidation of the isolated compound(s). One of the compounds isolated was screened for anti-leishmanial activity against promastigotes of Leishmania donovani and anti-tumour activity on K562 leukemic cell line. Results: A pentacyclic triterpenoid compound was isolated and designated as taraxerone, and then characterized as d-friedoolean-14-en, 3 one together with s-sitosterol and a long chain lipid fraction. This compound showed in vitro anti-leishmanial activity against promastigotes of Leishmania donovani (strain AG 83) and anti-tumour activity on K562 leukemic cell line. Conclusion: A pentacyclic triterpenoid compound designated as taraxerone and characterized as Dfriedoolean- 14-en, 3 one together was successfully isolated. The structure was determined on the basis of spectral analysis (IR, MASS, NMR (PMR, CMR and DEPT) and the compound demonstrated in vitro anti-leishmanial and anti-tumour activities.

Reactive processing of polymers: Structural characterisation of products by 1H and 13C NMR spectroscopy for glycidyl methacrylate grafting onto EPR in the absence and presence of a reactive comonomer

Grafted GMA on EPR samples were prepared in a Thermo-Haake internal mixer by free radical melt grafting reactions in the absence (conventional system; EPR–g–GMA CONV) and presence of the reactive comonomer divinyl benzene, DVB (EPR–g–GMA DVB). The GMA-homopolymer (poly-GMA), a major side reaction product in the conventional system, was almost completely absent in the DVB-containing system, the latter also resulted in a much higher level of GMA grafting. A comprehensive microstructure analysis of the formed poly-GMA was performed based on one-dimensional 1H and 13C NMR spectroscopy and the complete spectral assignments were supported by two-dimensional NMR techniques based on long range two and three bond order carbon–proton couplings from HMBC (Heteronuclear Multiple Bond Coherence) and that of one bond carbon–proton couplings from HSQC (Heteronuclear Single Quantum Coherence), as well as the use of Distortionless Enhancement by Polarization Transfer (DEPT) NMR spectroscopy. The unambiguous analysis of the stereochemical configuration of poly-GMA was further used to help understand the microstructures of the GMA-grafts obtained in the two different free radical melt grafting reactions, the conventional and comonomer-containing systems. In the grafted GMA, in the conventional system (EPR–g–GMA CONV), the methylene protons of the GMA were found to be sensitive to tetrad configurational sequences and the results showed that 56% of the GMA sequence in the graft is in atactic configuration and 42% is in syndiotactic configuration whereas the poly-GMA was predominantly syndiotactic. The differences in the microstructures of the graft in the conventional EPR–g–GMA CONV and the DVB-containing (EPR–g–GMA DVB) systems is also reported

Structural determination of quercusides A and B, new flavonoid glucosides from Quercus incana, by 1D and 2D NMR spectroscopy

Quercusides A and B, new flavonoid glucosides have been isolated from the chloroform soluble fractions of Quercus incana. Their structures were assigned from (1)H and (13)C nuclear magnetic resonance spectra, distortionless enhancement by polarization transfer (DEPT) and by correlation spectroscopy, heteronuclear multiple quantum correlation (HMQC) and heteronuclear multiple bond correlation (HMBC) experiments. Lupeol, beta-sitosterol and ursolic acid have also been reported from this species.

Electrochemical oxidation of catechol in the presence of an aromatic amine in aqueous media

The electrochemical oxidation of catechol has been studied in the presence of p-nitroaniline as a nucleophile in aqueous media at the surface of glassy carbon electrode, using cyclic voltammetry. The products of electrosynthesis have been purified and characterized by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), 13C NMR, and distortionless enhancement by polarization transfer (DEPT), and the mechanism of anodic oxidation was deduced from voltammetric and spectroscopic data.

New Triterpenoid Saponins from Glochidion eriocarpum and Their Cytotoxic Activity

Combined chromatographic methods led to the isolation of two new triterpenoid saponins, glochieriosides A and B (1, 2), from the aerial parts of Glochidion eriocarpum, along with three known triterpenes, glochidone (3), lup-20(29)-en-3beta,23-diol (4), and lup-20(29)-en-1beta,3beta-diol (5). The structures of the new saponins were determined to be 22beta-benzoyloxy-3beta,16beta,28-trihydroxyolean-12-ene 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranoside] (1) and 22beta-benzoyloxy-3beta,16beta,28-trihydroxyolean-12-ene 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranoside] (2). The structural elucidation was accomplished by using a combination of the 1D-NMR (1H-, 13C-NMR, distortionless enhancement by polarization transfer (DEPT) 90 degrees , and DEPT 135 degrees ), 2D-NMR (1H-1H correlation spectroscopy, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, and rotating frame Overhouser effect spectroscopy), ESI-MS, and HR-FAB-MS experiments. Glochieriosides A and B exhibited significant cytotoxic activity against HL-60, HT-29, MCF-7 and SK-OV-3 human cancer cell lines with the IC50 values of 5.5, 6.8, 29.1, and 22.7 microM for glochierioside A, respectively, and 6.6, 18.6, 36.1, and 16.0 microM for glochierioside B. Glochidone was less active with IC50 values greater than 100 microM while lup-20(29)-en-1beta,3beta-diol was moderately active with IC50 values of 43.3, 67.0, 66.1, and 48.0 microM, respectively.

Isolation and Crystal Structures of Both Enol and Keto Tautomer Intermediates in a Hydration of an Alkyne−Carboxylic Acid Ester Catalyzed by Iridium Complexes in Water

Hydration of tetrolic acid ethyl ester as an alkyne-carboxylic acid ester catalyzed by an Ir-aqua complex [Ir(III)Cp*(bpy)(OH2)]2+ (1, Cp* = eta5-C5Me5, bpy = 2,2'-bipyridine) in water provides ethyl acetoacetate as a beta-keto acid ester. We report the successful isolation of both an Ir-enol tautomer intermediate [IrIIICp*(bpy){CH3C(OH)=CC(O)OC2H5}]+ (2) and an Ir-keto tautomer intermediate [Ir(III)Cp*(bpy){CH3C(O)CHC(O)OC2H5}]+ (3) in the catalytic hydration by optimizing the conditions of the isolation, such as pH of the solution, reaction time, and selection of counteranions. The structures of the enol and keto complexes with characteristic Ir-(sp2carbon) bond and Ir-(sp3 carbon) bond, respectively, were unequivocally determined by X-ray analysis, IR, electrospray ionization mass spectrometry (ESI-MS), and NMR studies including 1H, 13C, distortionless enhancement by polarization transfer (DEPT) and correlation spectroscopy (COSY) experiments. It was confirmed that the hydration of tetrolic acid ethyl ester catalyzed by 2 or 3 as initial catalysts provides ethyl acetoacetate. Mechanism of the catalytic hydration of tetrolic acid ethyl ester as an alkyne-carboxylic acid ester is discussed based on isotopic labeling experiments with the Ir-enol and Ir-keto tautomers.

NMR study of the spatial structure of synthetic pyrethroids

The spatial isomers of the new synthetic analogs of ethyl permithrinic ether and permethrin were investigated by NMR (1H, 13C, DEPT (distortionless enhancement by polarization transfer), COSY (correlation spectroscopy), CHCORR (heteronuclear (C, H) shift correlation spectroscopy), ROESY (rotating-frame Overhauser effect spectroscopy)). Several tendencies were revealed in the 1H and 13C chemical shifts of the α atoms of the substituents in the 2nd and 3rd positions of the cyclopropane ring. For substituents cis-orientated relative to the ester group, the spectra show a paramagnetic shift of the 1H signals and the diamagnetic shift of the 13C signals relative to the trans-orientated substituents. The 1H and 13C chemical shifts of the α atoms of the substituents in the 2nd and 3rd positions of the cyclopropane ring permit an unambiguous determination of the stereochemistry of ethyl permethrinic ether and permethrin analogs.

The synthesis conditions, characterizations and thermal degradation studies of an etherified starch from an unconventional source

Starch isolated from an under-utilized legume plant (pigeon pea) was carboxymethylated. Influences of reaction parameters were investigated on the degree of substitution (DS) and the reaction efficiency (RE). Studies showed that optimal DS of 1.12 could be reached at reaction efficiency of 80.6% in isopropanol–water reaction medium (40 °C, 3 h). Scanning electron microscopy showed that after carboxymethylation, the granular appearance of the native starch was distorted. Wide-angle X-ray diffractometry revealed that crystallinity was reduced significantly after carboxymethylation. The infrared spectra revealed new bands in the carboxymethyl starch at ν = 1600, 1426 and 1324 cm −1 which were attributed to carbonyl functional groups vibration, –CH 2 scissoring and OH bending vibration, respectively. Broad-band 13C NMR of carboxymethyl starch showed an intense peak at δ = 180.3 ppm which was assigned to carbonyl carbon on the carboxymethyl substituent on the AGU (Anhydroglucose Unit). DEPT (Distortionless Enhancement by Polarization Transfer) 135 NMR showed negative signals which correspond to methylene carbons on the AGU. Differential Scanning Calorimetry (DSC) suggests loss of crystallinity after carboxymethylation. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) show that thermal stability improved after carboxymethylation. The study provides information on the preparation and characterization of a biomaterial from a new source which could be used alone or in the preparation of other functional polymers for diverse polymer applications.