Research Article Reaction Behavior of Cellulose in the...

Research ArticleReaction Behavior of Cellulose in the HomogeneousEsterification of Bagasse Modified with Phthalic Anhydride inIonic Liquid 1-Allyl-3-methylimidazium Chloride

Hui-Hui Wang1 Xue-Qin Zhang1 Piao Long1 Ai-Ping Zhang2

Chuan-Fu Liu1 and Run-Cang Sun3

1State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou 510640 China2College of Materials and Energy Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant GermplasmSouth China Agricultural University Guangzhou 510642 China3Beijing Key Laboratory of Lignocellulosic Chemistry Beijing Forestry University Beijing 100083 China

Correspondence should be addressed to Chuan-Fu Liu chfliuscuteducn

Received 3 June 2016 Revised 11 August 2016 Accepted 31 August 2016

Academic Editor Antje Potthast

Copyright copy 2016 Hui-Hui Wang et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In order to elucidate the reaction behavior of cellulose component in bagasse the homogeneous phthalation of bagasse wasinvestigated comparatively with the isolated cellulose in 1-allyl-3-methylimidazium chloride (AmimCl) with phthalic anhydride(PA) at the dosage of 10ndash50mmolg The phthalation degrees of bagasse and the isolated cellulose were in the range of 566 to2271 and 1161 to 4411 respectively A phthalation degree increase of cellulose was proportional to phthalic anhydride dosagedue to its regular macromolecular structure and followed the equation 119910PDI = 0004119909 minus 002 FT-IR and 2D HSQC NMR analysesconfirmed the attachment of phthaloyl group The phthalation reactivity of the three hydroxyls in the isolated cellulose followedthe order of C-6 gt C-2 gt C-3 and the more selective phthalation to C-6 position was found in the cellulose component in bagasseThese results provide detailed understanding of the homogenous modification mechanism of lignocellulose

1 Introduction

Bagasse an abundant agricultural lignocellulosic by-productrepresents a potentially sustainable biomass resource to createfuels chemicals and composites to replace fossil-based prod-uctsThebioproducts derived frombagasse have been appliedin many industrial fields such as coating food-packing andpainting [1 2] paving the way to replace the fossil-basedproducts

However bagasse presents considerable chemical andphysical inertness such as complex structure strong hydro-gen bonds and high crystallinity of cellulose which restrictsthe dissolution of bagasse in common organic or inorganicsolvents Fortunately some novel solvents or solvent systemshave been reported to dissolve lignocellulosic materials [3ndash5] Among these novel solvents ionic liquids (ILs) havereceived much attention due to the recoverability designabil-ity extremely low vapor pressure inflammableness and

thermal and chemical stability [6] The bridge between ILsand biomass has been built from over ten years ago [7]andmany homogeneousmodifications of lignocellulose havebeen investigated in ILs [8 9] among which esterificationof the available reactive hydroxyls is relatively easily accom-plished However due to the obstacle to obtain detailedinformation of esterified lignocellulose the homogeneousesterification mechanism was little studied

To obtain more detailed structural information manyefforts have been devoted to establish efficient solvent systemsfor the complete and nonderivative dissolution of plant cellwalls Ball-milling was reported to benefit the dissolutionof lignocellulose for spectroscopic analysis [10] The com-bination of ball-milling and efficient solvent systems makesthe characterization of lignocellulosic cell walls with 2DHSQC NMR feasible which could offset the lack of detailedinformation provided by solid-state 13C-NMR commonly

Hindawi Publishing CorporationInternational Journal of Polymer ScienceVolume 2016 Article ID 2361284 9 pageshttpdxdoiorg10115520162361284

2 International Journal of Polymer Science

used in the previous studies [11 12] Based on ball-millinga so-called ldquogel-state NMR methodrdquo was developed withsolution-state 2D NMR [13 14] The assignment of thecorrelations in 2D HSQC NMR spectra was reported fromvarious cellulose models [15] providing the database of cellwall samples for further investigation

Considering the complex structure and various linkagesamong different components of lignocellulose the homoge-neous phthalation of lignocellulose was investigated compar-atively with the isolated component under the same condi-tions to elucidate the mechanism In the present study theisolated cellulose and bagasse were comparatively phthalatedThe phthalated samples were characterized with FT-IR 1HNMR 13C NMR and 2D HSQC NMR to study the reactionbehavior of cellulose fractions in bagasse phthalation Thethermal stability of the phthalated samples was also studiedwith thermogravimetric analysis (TGA)

2 Material and Methods

21 Materials Bagasse was obtained from a local factory(Jiangmen China) It was dried in sunlight and cut intosmall pieces The cut bagasse was ground and screened toprepare 20ndash40 mesh size particles (450ndash900 120583m) The driedground samples were extracted with toluene-ethanol (2 1vv) for 4 h and then dried in a cabinet oven with aircirculation at 50∘C for 24 h The extractive-free bagasse wasdivided into two parts one was finely ball-milled for 48 hin a planetary BM4 ball-miller (Grinder Beijing China)at 608 rpm for further characterization and modificationand the other for the isolation of cellulose The contentsof cellulose hemicelluloses and lignin in the extractive-free bagasse were determined as 4485 3313 and 1914respectively according to the standard NREL methods [16]

1-Allyl-3-methylimidazium chloride (AmimCl) IL waspurchased from ChengJie Chemical Co Ltd (ShanghaiChina) and used as received Phthalic anhydride (PA) andother chemicals were of analytical grade and were purchasedfrom Guangzhou Chemical Reagent Factory (GuangdongChina)

22 Isolation of Cellulose fromBagasse Cellulose was isolatedfrom the extractive-free bagasse according to the previousliterature [12] Briefly the extractive-free bagasse was delig-nified at 75∘C for 2 h with sodium chlorite at pH 38ndash40adjusted by 10 acetic acid The solid residues were collectedby filtration washed with distilled water until neutral pHthenwashedwith ethanol and dried in a cabinet oven for 16 hat 50∘C The solid residues were extracted with 10 NaOHat a solid to liquor ratio of 1 20 gmL for 10 h at 20∘C Thealkaline extraction procedure was repeated thrice to removethe noncellulosic substances The solid residues were filteredout washed thoroughly with distilled water then washedwith ethanol and dried in an ovenwith air circulation at 50∘Cfor 24 h

23 Homogeneous Phthalation The isolated cellulose (48 g)was finely ball-milled for 48 h in a planetary BM4 ball-miller(Grinder Beijing China) at 608 rpm Ball-milled cellulose

or bagasse (05 g) was dispersed in 10 g AmimCl at roomtemperature with agitation under nitrogen atmosphere for10min and the suspension was stirred at 90∘C for 4 h toobtain a clear solution PA was added portionwise to thesolution with the dosage of 10 20 30 40 and 50mmolgrespectively The mixture was agitated at 90∘C for 90minunder N

2atmosphere for phthalation After the required

time the resulted solution was cooled to room temperatureand added into 200mL ethanol with agitation The suspen-sion was further continuously stirred for 12 h to thoroughlyprecipitate the phthalated products The solid residues werefiltered out thoroughlywashedwith ethanol (four times total800mL) to remove unreacted PA AmimCl and byproductsand freeze-dried for further characterization [17]

24 Determination of Phthalation Degree The substitutedhydroxyl contents of phthalated samples were determinedbased on the equivalent volume of NaOH and HCl standardsolution by back-titration method [18] according to thefollowing

SHC =119888NaOH times 119881NaOH minus 119888HCl times 119881HCl

2times1000

119898 (1)

where SHC (mmolg) is the substituted hydroxyls contents119898 (g) is the dry weight of sample analyzed 119888NaOH (molL) isthe molarity of NaOH standard solution 119881NaOH (mL) is theconsumed volume of NaOH standard solution 119888HCl (molL)is the molarity of HCl standard solution and119881HCl (mL) is theconsumed volume of HCl standard solution

Based on the assumption that cellulose is composed ofanhydroglucose (AGU) the theoretical hydroxyl contents ofthe unmodified cellulose were calculated from its macro-molecular structure according to (2) the theoretical hydroxylcontents of phthalated bagasse samples were calculated basedon the contents of three main components according to(3) and phthalation degree of cellulose and bagasse wascalculated based on (4)

THCC =1000

162times 3 (2)

where THCC is the theoretical hydroxyl groups content ofunmodified cellulose 162 gmol is the molar mass of AGUand 3 is the number of hydroxyl groups on each AGU

THCB = THCC times 4485 + THCH times 3313 + THCL

times 1914(3)

where THCB THCC THCH and THCL are the theoreticalhydroxyl groups content of the unmodified bagasse cellulosehemicelluloses and lignin respectively and 4485 3313and 1914 are the contents of cellulose hemicelluloses andlignin respectively in the extractive-free bagasse The theo-retical hydroxyl contents of the unmodified hemicellulosesand lignin were 1515 and 513mmolg (data not shown)

PD = SHCTHCtimes 100 (4)

where PD is the phthalation degree SHC is the substitutedhydroxyl contents and THC is the theoretical hydroxylcontents

International Journal of Polymer Science 3

Table 1 The substituted hydroxyl contents and phthalation degrees of the phthalated cellulose and bagasse

Sample no Temp (∘C) PA dosagea (mmolg) Solvent Time (h) THCb (mmolg) SHCc (mmolg) PDd ()C1 90 10 AmimCl 15 1852 215 1161C2 90 20 AmimCl 15 1852 261 1409C3 90 30 AmimCl 15 1852 371 2003C4 90 40 AmimCl 15 1852 551 2975C5 90 50 AmimCl 15 1852 817 4411S1 90 10 AmimCl 15 1431 081 566S2 90 20 AmimCl 15 1431 147 1027S3 90 30 AmimCl 15 1431 194 1356S4 90 40 AmimCl 15 1431 292 2041S5 90 50 AmimCl 15 1431 325 2271aThe ratio of phthalic anhydride (mmol) to biomass material (g bagasse or cellulose)bTheoretical hydroxyls content of unmodified biomass materialcSubstituted hydroxyl contents determined by back titrationdPhthalation degree

25 Characterization FT-IR spectra were obtained on FT-IRspectrophotometer (Nicolet 510) using a KBr disk containingapproximately 1 finely ground samples Thirty-two scanswere taken for each sample with a resolution of 2 cmminus1 intransmittance mode in the range of 4000ndash400 cmminus1

The 1H NMR 13C NMR and 2D HSQC NMR spectrawere recorded from 40mg samples in 05mL DMSO-119889

6on a

Bruker Advance III 600MHz spectrometer (Germany) The1H NMR and 13C NMR spectra were recorded accordingto the previous literature [19] For the 1H NMR analysisthe detailed collecting and processing parameters were asfollows number of scans 16 receiver gain 61 acquisitiontime 27263 s relaxation delay 10 s pulse width 110 sspectrometer frequency 60017MHz and spectral width120192Hz For 13C NMR analysis the detailed collectingand processing parameters were as follows number of scans10000 receiver gain 187 acquisition time 09088 s relax-ation delay 20 s pulse width 120 s spectrometer frequency15091MHz and spectral width 360577Hz For 2D HSQCanalysis the detailed collecting and processing parameterswere listed as follows number of scans 32 receiver gain187 relaxation delay 15 s pulse width 110 s acquisition time01420 s spectra frequency 6001715091Hz and spectrawidth 72115248756Hz

The thermal stability of cellulose samples was studiedusing thermogravimetric analysis (TGA) on a thermal ana-lyzer (SDT Q600 TA Instrument) The apparatus was con-tinually flushed with nitrogen The sample weighed between8 and 10mg and the scans were run from 50∘C to 500∘C at aheating rate of 10∘Cmin

3 Results and Discussion

31 Homogeneous Phthalation of Cellulose in Bagasse It iswell known that the complex inhomogeneous structure ofbagasse is formed by three main components including

cellulose hemicelluloses and lignin Actually the homoge-neous phthalation of bagasse is the phthalation of the abun-dant reactive hydroxyl groups in the three main componentsTherefore in order to elucidate the mechanism of homoge-neous phthalation the isolated cellulose was comparativelyphthalated under the same conditions as bagasse to estimatethe detailed reaction behavior of cellulose in the phthalationof bagasse mixture in AmimCl as listed in Table 1

Theoretically each AGU contains three hydroxyl groupsand the free hydroxyl group content of the isolated celluloseis 1852mmolg After phthalation in AmimCl some ofthe hydroxyl groups were substituted as shown in Table 1With the increment of PA dosage from 10 to 20 30 40and 50mmolg the substituted hydroxyl contents in thephthalated cellulose estimated from back titration increasedfrom 215 to 261 371 551 and 817mmolg respectively andthe free hydroxyl content decreased from 1637 to 1591 14811301 and 1035mmolg respectively Correspondingly thephthalation degree increased from 1161 to 1409 20032975 and 4411 respectively These results confirmedthe occurrence of phthalation of the isolated cellulose underthe selected conditions Similarly the substituted hydroxylcontents in bagasse increased from 081 to 147 194 292 and325mmolg respectively with the increment of PA dosagefrom 10 to 20 30 40 and 50mmolg The free hydroxylgroup content in unmodified bagasse that is the theoreticalhydroxyls content was 1431mmolg estimated from the threemain components based on their contents The free hydroxylcontent correspondingly decreased from 1350 to 1284 12371139 and 1106mmolg respectively and the phthalationdegree increased from 566 to 1027 1356 2041 and2271 respectively Comparatively the phthalation degreeof bagasse was lower than that of the isolated celluloseindicating the higher phthalation ability of the isolatedcellulose Comparatively the decreased phthalation degreeof bagasse was due to the different contents and reactivityof hydroxyls in the three main components compared with


PD (

)

010

015

020

025

030

035

040

045

10 20 30 40 50PA dosage (mmolg)

(a)

PDI

002

004

006

008

010

012

014

PA dosage (mmolg)10 20 30 40

(b)

Figure 1 Dependence of phthalation degree ((PD) (a)) and phthalation degree increase ((PDI) (b)) on phthalic anhydride dosage

the isolated ones In addition a very interesting phenomenonwas found for the phthalation degree increase (PDI) PDIof cellulose was proportional to phthalic anhydride dosagewhich followed the equation of119910PDI = 0004119909minus002 as shownin Figure 1 This regular relation was probably due to theregular macromolecular structure of cellulose The detaileddifferences of the hydroxyl reactivity in different positionsneed to be further clarified

32 FT-IR Analysis FT-IR spectra of unmodified cellulose(C0 spectrum a) and phthalated cellulose samples (C1spectrum b C3 spectrum c C4 spectrum d) are illustratedin Figure 2 The bands were assigned based on the reportedliteratures [20 21] Compared with unmodified cellulose thenoticeable bands at 1716 1602 1327 and 747 cmminus1 in thephthalated samples correspond to carbonyl group in estersaromatic ring vibration C-O stretching in carboxyl and out-of-plane C-H bending of benzene respectively The presenceof these bands indicated the successful phthalation of cellu-lose It should be noted that the intensities of these bandsincreased with the increment of PA dosage corresponding tothe increased substituted hydroxyl contents and phthalationdegree in Table 1

33 NMRAnalysis To further elucidate the detailed behaviorof hydroxyls in different positions in AGU during phthala-tion the unmodified (C0) and phthalated cellulose (C5) aswell as phthalated bagasse (S5) were further characterizedwith 1D (1H and 13C) and 2D (HSQC) NMR technology inDMSO-119889

6 as illustrated in Figures 3 and 4

1H NMR spectra of unmodified cellulose (C0 spectruma) phthalated cellulose (C5 spectrum b) and phthalatedbagasse (S5 spectrum c) are present in Figure 3 As can beseen the relevant signals are present in two regions namelythe AGU protons region (450ndash300 ppm) and the phthaloylprotons region (800ndash700 ppm) Compared with unmodified

4000 3500 3000 2500 2000 1500 1000 500

1716 1602 10451327

747

ab

c

d

Wavenumbers (cmminus1)

Figure 2 FT-IR spectra of unmodified cellulose (C0 spectrum a)and modified cellulose with phthalic anhydride dosage at 10 (C1spectrum b) 30 (C3 spectrum c) and 40 (C4 spectrum d) mmolg

cellulose the presence of peaks at 787 (H-10) 776 (H-13)769 (H-11) and 760 (H-12) ppm for phthaloyl protons in thephthalated cellulose and phthalated bagasse confirmed thephthalation of cellulose and bagasse

The 13C NMR spectra of unmodified cellulose (C0spectrum d) phthalated cellulose (C5 spectrum e) andphthalated bagasse (S5 spectrum f) exhibit main signalsin Figure 3 the carbon skeletons of AGU at 10283 (C-1) 8043 (C-4) 7527 (C-5) 7527 (C-3) 7038 (C-2) and6074 (C-6) ppm were well resolved In the region 180ndash120 ppm the cross-peaks at 16885 (C-7) 16757 (C-14) 13495(C-8) 13334 (C-9) 13220 (C-13) 13171 (C-10) 13086 (C-12) and 12909 (C-11) ppm were assigned to carbons of thephthaloyl groups respectively in phthalated cellulose andphthalated bagasse confirming the attachment of phthaloylgroups onto cellulose and bagasse This result was consistent


68 7 5 4 3 2 1(ppm)

DMSO

O

OH

O

HOHO

O

123

4 56 H-1-H-6

(a)

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

R = H or

O

O

OH

OO

ORO

ROO

O

O

123

4 56

78

91011

1213

14HO

H-10 -11 -12 -13

68 7 5 4 3 2 1(ppm)

(b)

8 7 6 5 4 3 2 1

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

H-10 -11 -12 -13

(ppm)

(c)

180 160 140 120 100 80 60 40 20

C-1

C-5 -3

C-6C-2 DMSO

C-4

(ppm)

(d)

180 160 140 120 100 80 60 40 20

C-1

C-7 -14

C-4

C-5 -3C-2

C-6DMSO

C-8 -9 -10 -11 -12 -13

(ppm)

(e)

180 160 140 120 100 80 60 40 20

C-7 -14C-1

C-4

C-5 -3

C-6

C-2 DMSO

(ppm)

C-8 -9 -10 -11 -12 -13

(f)

Figure 3 The 1H ((a) (b) and (c)) and 13C ((d) (e) and (f)) NMR spectra of unmodified cellulose (C0) phthalated cellulose (C5) andphthalated bagasse (S5)

with the previously reported esterification of wood withcyclic anhydride (succinic anhydride maleic anhydride andphthalic anhydride) as main monoesterification below 100∘C[22] However the reactivity of hydroxyls from phthalatedcellulose andphthalated bagasse during homogeneous phtha-lation could not be revealed from the 1HNMR and 13CNMRanalysesTherefore further investigation with 2DHSQCwasnecessary

TheHSQC spectra of unmodified cellulose (C0 spectruma) and phthalated cellulose (C5 spectra b and d) as well asthe carbohydrate regions of phthalated bagasse (S5 spectrumc) are shown in Figure 4 The primary polysaccharidecorrelation peaks in HSQC spectra appeared in the range of110ndash55 ppm (13C) and 60ndash25 ppm (1H) These correlations

were assigned based on cellulose models reported previously[15] as listed in Table 2 The primary peaks of cellulose inter-nal units (C-I) in this region were clearly observed from theunmodified cellulose at 7349306 [C-I

2(C2H2)] 7533336

[C-I3(C3H3)] 8085333 [C-I

4(C4H4)] 7714318 [C-

I5(C5H5)] and 10344433 [C-I

1(C1H1)] ppm the two

internal C-I6(C6H6) peaks were also distinctively located at

6077379 and 6077358 ppmThe end-group correlations were well resolved in the

unmodified cellulose however some peaks were super-imposed with other peaks The correlations for non-reducing-end C-NR

6(C6H6) were well separated from

the internal C-I6(C6H6) and appeared at 6150369 and

6150339 ppm That for C-NR4(C4H4) was clearly present


3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734

C-I5 + C-NR5 + C-NR3

C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)

Figure 4 2D HSQC NMR spectra of unmodified cellulose (C0 spectrum a) phthalated cellulose (C5 spectra b and d) and phthalatedbagasse (S5 spectrum c)

Table 2 Primary NMR correlations in DMSO-1198896for cellulose modified with phthalic anhydride

Glycosyl residue1H amp 13C chemical shifts (ppm)

1 2 3 4 5 6a 6b

Cellulose (internal)1H 431 305 336 330 316 356 37713C 10326 7356 7524 8097 7718 6074 6074

Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080

at 7054305 ppm while the correlations at 7377298 ppmfor C-NR

2(C2H2) were located very close to the internal C-

I2(C2H2) Those for C-NR

3(C3H3) and C-NR

5(C5H5)

had the coincident chemical shifts and overlapped withthe internal C-I

5(C5H5) correlation at 7707318 ppm The

anomeric peak from non-reducing-end C-NR1appeared

at 10365423 ppm (C1H1) The 120572- and 120573-anomer from

reducing-end correlations of cellulose were clearly separatedfrom those of the internal units The C

1H1correlation from

the reducing-terminal-end of 120572-d-glucuronic polysaccharide(120572-d-Glcp) (C-R120572

1) was at 9244489 ppm while the anal-

ogous 120573-d-Glcp (C-R1205731) correlation was at 10331514 ppm


0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

Figure 5 The TGDTG curves of unmodified cellulose (C0 curve a) and phthalated cellulose samples (C1 curve b C5 curve c)

Despite the conformational complexity primary peakswere evidently assigned from 120572-d-Glcp 7268316 [C-R120572

2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-

R1205725(C5H5)] ppm Similarly C-R120573

2(C2H2) and C-R120573

5

(C5H5) were well resolved at 7493293 and 7513306 ppm

respectively However C-R1205733(C3H3) was coincident withC-

I3at 7524325 ppm In addition C-R120572

4(C4H4) and C-R120573

4

(C4H4) were coincident at 8136331 ppm C-R120572

6(C6H6)

and C-R1205736(C6H6) also were close together at 6080372 and

6080356 ppm and were buried between the internal C-I6

peaks These results indicated that ball-milling treatment ledto the severe degradation of cellulosic macromolecules

Compared with those in the unmodified cellulose thereducing-end and non-reducing-end peaks which resultedfrom low-molecular fractions were significantly improvedin the phthalated cellulose and the phthalated bagasseindicating the degradation of cellulose macromolecules inIL AmimCl during dissolution and modification This resultcorresponded to the FT-IR analysis and similar degradationwas also reported in the previous publications [23 24] Theprimary internal cellulose peaks were clearly observed inthe phthalated cellulose (C5) and bagasse (S5) at 7354307[C-I2(C2H2)] 7511336 [C-I

3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1

(C1H1)] ppm the two internal C-I

6(C6H6) peaks were also

distinctively located at 6066379 and 6052360 ppmThe presence of the correlations from aryl groups in the

phthalated cellulose confirmed the attachment of phthaloylgroup onto cellulose More importantly two peaks fromsubstituted C

6in phthalated internal units (C-I1015840) [C-I1015840

6

(C6H6)] appeared at 6470379 and 6470442 ppm and

the peak from substituted C2in internal unit [C-I1015840

2(C2H2)]

was located at 7421460 ppm confirming the successfulphthalation of cellulose at C-6 and C-2 positions Howeverthe substituted C

3was almost not detected which suggested

that most of phthaloyl group was attached onto C-6 and C-2

positions The relative percentage of phthalation on differentpositions could be evaluated upon the integral area of thecharacteristic substituted correlations The results indicatedthat 241 and 759 of phthaloyl group were attached toC2and C

6positions respectively The relative percentage of

phthalation at C-6 C-2 and C-3 positions of cellulose inphthalated bagasse S5 was 9474 526 and 0 respectivelyThese results indicated that the reaction behavior of cellulosein bagasse was similar to the isolated cellulose and thephthalation was more selective to C-6 position in bagassethan that in the isolated cellulose Obviously the phthalationdegree of the three hydroxyls in AGU followed the orderof C-6 gt C-2 gt C-3 This order was consistent with thepropionylation and butyrylation in AmimCl [25] On theother hand the phthalation degree of the hydroxyls on eachposition was easily calculated based on the integral area ofthe characteristic substituted and unsubstituted correlationsThe results showed that the phthalation degree in the isolatedcellulose was 630 201 and 0 respectively while that inbagasse was 1515 263 and 0 respectively These resultswere consistent with the abovementioned phthalation orderof three hydroxyls The relatively more selective phthalationfor the hydroxyl to C-6 position of cellulose component inbagasse than the isolated cellulose was primarily due to thedifferences of the phthalation reactivity of more complicatedhydroxyls in bagasse

34 Thermal Analysis The thermal behavior of unmodifiedcellulose and phthalated cellulose was studied by TGA in N

2

atmosphere Figure 5 illustrates the TGA and DTG curvesof the unmodified cellulose (C0 curve a) and phthalatedcellulose (C1 curve b C5 curve c) The decrease below100∘C was due to loss of moisture The initial decompositiontemperature of samples C0 C1 and C5 was 251∘C 245∘C and213∘C respectively At 50 weight loss the decompositiontemperature occurred at 304∘C 305∘C and 297∘C for samples


C0 C1 and C5 respectively The DTG curves suggestedthat the modified cellulose had higher thermal degradationrate than the unmodified one These data indicated that thedecreased thermal stability of phthalated cellulose is consis-tent with the results reported previously [26] Besides theinitial and midpoint decomposition temperatures of sampleC5 were both lower than those of sample C1 indicating thathigh phthalation degree tended to weaken thermal stabilityof modified cellulose

4 Conclusions

The phthalation degree of bagasse and the isolated celluloseranged from 566 to 2271 and from 1161 to 4411respectively The phthalation degree increase of cellulose wasproportional to phthalic anhydride dosage which followedthe equation of 119910PDI = 0004119909 minus 002 under the selectedconditions The reactivity of the three hydroxyls in cellulosefollowed the order of C-6 gt C-2 gt C-3 and more selectivephthalation to C-6 positions of cellulose component wasfound in bagasse than in the isolated cellulose These resultsprovide a detailed understanding of the homogenous modi-fication mechanism of lignocellulose

Competing Interests

The authors declare that they have no competing interests

Acknowledgments

This work was financially supported by the National NaturalScience Foundation of China (31170550 and 31170555) theFundamental Research Funds for the Central Universities(2014ZG0046) and theNational Program for Support of Top-Notch Young Professionals

References

[1] C T Duan N Zhao X L Yu X Y Zhang and J Xu ldquoChem-ically modified kapok fiber for fast adsorption of Pb2+ Cd2+Cu2+ from aqueous solutionrdquo Cellulose vol 20 no 2 pp 849--860 2013

[2] K Y Foo L K Lee and BHHameed ldquoPreparation of activatedcarbon from sugarcane bagasse by microwave assisted activa-tion for the remediation of semi-aerobic landfill leachaterdquo Bio-resource Technology vol 134 pp 166ndash172 2013

[3] F C Lu and J Ralph ldquoNon-degradative dissolution and acety-lation of ball-milled plant cell walls high-resolution solution-state NMRrdquo Plant Journal vol 35 no 4 pp 535ndash544 2003

[4] M Fasching P Schroder R P Wollboldt H K Weber andH Sixta ldquoA new and facile method for isolation of lignin fromwood based on complete wood dissolutionrdquoHolzforschung vol62 no 1 pp 15ndash23 2008

[5] T Q Yuan J He F Xu and R C Sun ldquoA new vision inthe research of biomass resources complete-lignocellulose-dissolution systemrdquo Progress in Chemistry vol 22 no 2-3 pp472ndash481 2010

[6] S D Zhu Y X Wu Q M Chen et al ldquoDissolution of cellulosewith ionic liquids and its application a mini-reviewrdquo GreenChemistry vol 8 no 4 pp 325ndash327 2006

[7] R P Swatloski S K Spear J D Holbrey and R D Rogers ldquoDis-solution of cellose with ionic liquidsrdquo Journal of the AmericanChemical Society vol 124 no 18 pp 4974ndash4975 2002

[8] E Rude and M-P G Laborie ldquoCarbon-13 cross-polarizationmagic-angle-spinning nuclear magnetic resonance investiga-tion of the interactions between maleic anhydride graftedpolypropylene and wood polymersrdquo Applied Spectroscopy vol62 no 5 pp 563ndash568 2008

[9] J C P De Melo E C Da Silva Filho S A A Santana andC Airoldi ldquoMaleic anhydride incorporated onto cellulose andthermodynamics of cation-exchange process at the solidliquidinterfacerdquo Colloids and Surfaces A Physicochemical and Engi-neering Aspects vol 346 no 1ndash3 pp 138ndash145 2009

[10] C Qu T KishimotoM KishinoMHamada andNNakajimaldquoHeteronuclear single-quantum coherence nuclear magneticresonance (HSQC NMR) characterization of acetylated fir(Abies sachallnensis MAST) wood regenerated from ionic liq-uidrdquo Journal of Agricultural and Food Chemistry vol 59 no 10pp 5382ndash5389 2011

[11] X-W Peng J-L Ren and R-C Sun ldquoHomogeneous esterifica-tion of xylan-rich hemicelluloseswithmaleic anhydride in ionicliquidrdquo Biomacromolecules vol 11 no 12 pp 3519ndash3524 2010

[12] C-F Liu R-C Sun M-H Qin et al ldquoChemical modificationof ultrasound-pretreated sugarcane bagasse with maleic anhy-driderdquo Industrial Crops and Products vol 26 no 2 pp 212ndash2192007

[13] H Kim J Ralph and T Akiyama ldquoSolution-state 2D NMRof ball-milled plant cell wall gels in DMSO-d

6rdquo BioEnergy

Research vol 1 no 1 pp 56ndash66 2008[14] H Kim and J Ralph ldquoSolution-state 2D NMR of ball-milled

plant cell wall gels in DMSO-d6pyridine-d

5rdquo Organic and Bio-

molecular Chemistry vol 8 no 3 pp 576ndash591 2010[15] H Kim and J Ralph ldquoA gel-state 2D-NMR method for plant

cell wall profiling and analysis a model study with the amor-phous cellulose and xylan from ball-milled cotton lintersrdquo RSCAdvances vol 4 no 15 pp 7549ndash7560 2014

[16] A Sluiter B Hames R Ruiz et al ldquoLaboratory analytical pro-cedure (LAP) determination of structural carbohydrates andlignin in biomassrdquo Tech Rep NRELTP-510-42618 NationalRenewable Energy Laboratory Golden Colo USA 2008

[17] M J Chen and Q S Shi ldquoTransforming sugarcane bagasse intobioplastics via homogeneous modification with phthalic anhy-dride in ionic liquidrdquoACS Sustainable ChemistryampEngineeringvol 3 no 10 pp 2510ndash2515 2015

[18] C F Liu A P Zhang W Y Li F X Yue and R C SunldquoSuccinoylation of cellulose catalyzed with iodine in ionicliquidrdquo Industrial Crops and Products vol 31 no 2 pp 363ndash3692010

[19] C-Y Chen M-J Chen X-Q Zhang C-F Liu and R-CSun ldquoPer-O-acetylation of cellulose in dimethyl sulfoxide withcatalyzed transesterificationrdquo Journal of Agricultural and FoodChemistry vol 62 no 15 pp 3446ndash3452 2014

[20] M J Chen C Y Chen C F Liu and R C Sun ldquoHomogeneousmodification of sugarcane bagasse with maleic anhydride in1-butyl-3-methylimidazolium chloride without any catalystsrdquoIndustrial Crops and Products vol 46 pp 380ndash385 2013

[21] J Wu H Zhang J Zhang and J-S He ldquoHomogeneous acety-lation and regioselectivity of cellulose in a new ionic liquidrdquoChemical Journal of Chinese Universities vol 27 no 3 pp 592ndash594 2006


[22] H Matsuda ldquoPreparation and utilization of esterified woodsbearing carboxyl groupsrdquoWood Science and Technology vol 21no 1 pp 75ndash88 1987

[23] C F Liu R C Sun A P Zhang et al ldquoHomogeneousmodification of sugarcane bagasse cellulose with succinic anhy-dride using a ionic liquid as reaction mediumrdquo CarbohydrateResearch vol 342 no 7 pp 919ndash926 2007

[24] C F Liu R C Sun A P Zhang and J L Ren ldquoPreparationof sugarcane bagasse cellulosic phthalate using an ionic liquidas reaction mediumrdquo Carbohydrate Polymers vol 68 no 1 pp17ndash25 2007

[25] Y Luan J Zhang M Zhan J Wu J Zhang and J He ldquoHighlyefficient propionylation and butyralation of cellulose in an ionicliquid catalyzed by 4-dimethylminopyridinerdquo CarbohydratePolymers vol 92 no 1 pp 307ndash311 2013

[26] C-F Liu R-C Sun A-P Zhang M-H Qin J-L Ren andX-A Wang ldquoPreparation and characterization of phthalatedcellulose derivatives in room-temperature ionic liquid withoutcatalystsrdquo Journal of Agricultural and Food Chemistry vol 55no 6 pp 2399ndash2406 2007

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


used in the previous studies [11 12] Based on ball-millinga so-called ldquogel-state NMR methodrdquo was developed withsolution-state 2D NMR [13 14] The assignment of thecorrelations in 2D HSQC NMR spectra was reported fromvarious cellulose models [15] providing the database of cellwall samples for further investigation

Considering the complex structure and various linkagesamong different components of lignocellulose the homoge-neous phthalation of lignocellulose was investigated compar-atively with the isolated component under the same condi-tions to elucidate the mechanism In the present study theisolated cellulose and bagasse were comparatively phthalatedThe phthalated samples were characterized with FT-IR 1HNMR 13C NMR and 2D HSQC NMR to study the reactionbehavior of cellulose fractions in bagasse phthalation Thethermal stability of the phthalated samples was also studiedwith thermogravimetric analysis (TGA)

2 Material and Methods

21 Materials Bagasse was obtained from a local factory(Jiangmen China) It was dried in sunlight and cut intosmall pieces The cut bagasse was ground and screened toprepare 20ndash40 mesh size particles (450ndash900 120583m) The driedground samples were extracted with toluene-ethanol (2 1vv) for 4 h and then dried in a cabinet oven with aircirculation at 50∘C for 24 h The extractive-free bagasse wasdivided into two parts one was finely ball-milled for 48 hin a planetary BM4 ball-miller (Grinder Beijing China)at 608 rpm for further characterization and modificationand the other for the isolation of cellulose The contentsof cellulose hemicelluloses and lignin in the extractive-free bagasse were determined as 4485 3313 and 1914respectively according to the standard NREL methods [16]

1-Allyl-3-methylimidazium chloride (AmimCl) IL waspurchased from ChengJie Chemical Co Ltd (ShanghaiChina) and used as received Phthalic anhydride (PA) andother chemicals were of analytical grade and were purchasedfrom Guangzhou Chemical Reagent Factory (GuangdongChina)

22 Isolation of Cellulose fromBagasse Cellulose was isolatedfrom the extractive-free bagasse according to the previousliterature [12] Briefly the extractive-free bagasse was delig-nified at 75∘C for 2 h with sodium chlorite at pH 38ndash40adjusted by 10 acetic acid The solid residues were collectedby filtration washed with distilled water until neutral pHthenwashedwith ethanol and dried in a cabinet oven for 16 hat 50∘C The solid residues were extracted with 10 NaOHat a solid to liquor ratio of 1 20 gmL for 10 h at 20∘C Thealkaline extraction procedure was repeated thrice to removethe noncellulosic substances The solid residues were filteredout washed thoroughly with distilled water then washedwith ethanol and dried in an ovenwith air circulation at 50∘Cfor 24 h

23 Homogeneous Phthalation The isolated cellulose (48 g)was finely ball-milled for 48 h in a planetary BM4 ball-miller(Grinder Beijing China) at 608 rpm Ball-milled cellulose

or bagasse (05 g) was dispersed in 10 g AmimCl at roomtemperature with agitation under nitrogen atmosphere for10min and the suspension was stirred at 90∘C for 4 h toobtain a clear solution PA was added portionwise to thesolution with the dosage of 10 20 30 40 and 50mmolgrespectively The mixture was agitated at 90∘C for 90minunder N

2atmosphere for phthalation After the required

time the resulted solution was cooled to room temperatureand added into 200mL ethanol with agitation The suspen-sion was further continuously stirred for 12 h to thoroughlyprecipitate the phthalated products The solid residues werefiltered out thoroughlywashedwith ethanol (four times total800mL) to remove unreacted PA AmimCl and byproductsand freeze-dried for further characterization [17]

24 Determination of Phthalation Degree The substitutedhydroxyl contents of phthalated samples were determinedbased on the equivalent volume of NaOH and HCl standardsolution by back-titration method [18] according to thefollowing

SHC =119888NaOH times 119881NaOH minus 119888HCl times 119881HCl

2times1000

119898 (1)

where SHC (mmolg) is the substituted hydroxyls contents119898 (g) is the dry weight of sample analyzed 119888NaOH (molL) isthe molarity of NaOH standard solution 119881NaOH (mL) is theconsumed volume of NaOH standard solution 119888HCl (molL)is the molarity of HCl standard solution and119881HCl (mL) is theconsumed volume of HCl standard solution

Based on the assumption that cellulose is composed ofanhydroglucose (AGU) the theoretical hydroxyl contents ofthe unmodified cellulose were calculated from its macro-molecular structure according to (2) the theoretical hydroxylcontents of phthalated bagasse samples were calculated basedon the contents of three main components according to(3) and phthalation degree of cellulose and bagasse wascalculated based on (4)

THCC =1000

162times 3 (2)

where THCC is the theoretical hydroxyl groups content ofunmodified cellulose 162 gmol is the molar mass of AGUand 3 is the number of hydroxyl groups on each AGU

THCB = THCC times 4485 + THCH times 3313 + THCL

times 1914(3)

where THCB THCC THCH and THCL are the theoreticalhydroxyl groups content of the unmodified bagasse cellulosehemicelluloses and lignin respectively and 4485 3313and 1914 are the contents of cellulose hemicelluloses andlignin respectively in the extractive-free bagasse The theo-retical hydroxyl contents of the unmodified hemicellulosesand lignin were 1515 and 513mmolg (data not shown)

PD = SHCTHCtimes 100 (4)

where PD is the phthalation degree SHC is the substitutedhydroxyl contents and THC is the theoretical hydroxylcontents






6on a








PD (

)

010

015

020

025

030

035

040

045


(a)

PDI

002

004

006

008

010

012

014


(b)







4000 3500 3000 2500 2000 1500 1000 500

1716 1602 10451327

747

ab

c

d






68 7 5 4 3 2 1(ppm)

DMSO

O

OH

O

HOHO

O

123

4 56 H-1-H-6

(a)

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

R = H or

O

O

OH

OO

ORO

ROO

O

O

123

4 56

78

91011

1213

14HO

H-10 -11 -12 -13

68 7 5 4 3 2 1(ppm)

(b)

8 7 6 5 4 3 2 1

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

H-10 -11 -12 -13

(ppm)

(c)

180 160 140 120 100 80 60 40 20

C-1

C-5 -3

C-6C-2 DMSO

C-4

(ppm)

(d)

180 160 140 120 100 80 60 40 20

C-1

C-7 -14

C-4

C-5 -3C-2

C-6DMSO

C-8 -9 -10 -11 -12 -13

(ppm)

(e)

180 160 140 120 100 80 60 40 20

C-7 -14C-1

C-4

C-5 -3

C-6

C-2 DMSO

(ppm)

C-8 -9 -10 -11 -12 -13

(f)





2(C2H2)] 7533336

[C-I3(C3H3)] 8085333 [C-I

4(C4H4)] 7714318 [C-

I5(C5H5)] and 10344433 [C-I









3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734


C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)




1 2 3 4 5 6a 6b


Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080




3(C3H3) and C-NR

5(C5H5)






1H1correlation from





0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








6on a








PD (

)

010

015

020

025

030

035

040

045


(a)

PDI

002

004

006

008

010

012

014


(b)







4000 3500 3000 2500 2000 1500 1000 500

1716 1602 10451327

747

ab

c

d






68 7 5 4 3 2 1(ppm)

DMSO

O

OH

O

HOHO

O

123

4 56 H-1-H-6

(a)

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

R = H or

O

O

OH

OO

ORO

ROO

O

O

123

4 56

78

91011

1213

14HO

H-10 -11 -12 -13

68 7 5 4 3 2 1(ppm)

(b)

8 7 6 5 4 3 2 1

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

H-10 -11 -12 -13

(ppm)

(c)

180 160 140 120 100 80 60 40 20

C-1

C-5 -3

C-6C-2 DMSO

C-4

(ppm)

(d)

180 160 140 120 100 80 60 40 20

C-1

C-7 -14

C-4

C-5 -3C-2

C-6DMSO

C-8 -9 -10 -11 -12 -13

(ppm)

(e)

180 160 140 120 100 80 60 40 20

C-7 -14C-1

C-4

C-5 -3

C-6

C-2 DMSO

(ppm)

C-8 -9 -10 -11 -12 -13

(f)





2(C2H2)] 7533336

[C-I3(C3H3)] 8085333 [C-I

4(C4H4)] 7714318 [C-

I5(C5H5)] and 10344433 [C-I









3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734


C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)




1 2 3 4 5 6a 6b


Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080




3(C3H3) and C-NR

5(C5H5)






1H1correlation from





0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




PD (

)

010

015

020

025

030

035

040

045


(a)

PDI

002

004

006

008

010

012

014


(b)







4000 3500 3000 2500 2000 1500 1000 500

1716 1602 10451327

747

ab

c

d






68 7 5 4 3 2 1(ppm)

DMSO

O

OH

O

HOHO

O

123

4 56 H-1-H-6

(a)

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

R = H or

O

O

OH

OO

ORO

ROO

O

O

123

4 56

78

91011

1213

14HO

H-10 -11 -12 -13

68 7 5 4 3 2 1(ppm)

(b)

8 7 6 5 4 3 2 1

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

H-10 -11 -12 -13

(ppm)

(c)

180 160 140 120 100 80 60 40 20

C-1

C-5 -3

C-6C-2 DMSO

C-4

(ppm)

(d)

180 160 140 120 100 80 60 40 20

C-1

C-7 -14

C-4

C-5 -3C-2

C-6DMSO

C-8 -9 -10 -11 -12 -13

(ppm)

(e)

180 160 140 120 100 80 60 40 20

C-7 -14C-1

C-4

C-5 -3

C-6

C-2 DMSO

(ppm)

C-8 -9 -10 -11 -12 -13

(f)





2(C2H2)] 7533336

[C-I3(C3H3)] 8085333 [C-I

4(C4H4)] 7714318 [C-

I5(C5H5)] and 10344433 [C-I









3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734


C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)




1 2 3 4 5 6a 6b


Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080




3(C3H3) and C-NR

5(C5H5)






1H1correlation from





0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




68 7 5 4 3 2 1(ppm)

DMSO

O

OH

O

HOHO

O

123

4 56 H-1-H-6

(a)

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

R = H or

O

O

OH

OO

ORO

ROO

O

O

123

4 56

78

91011

1213

14HO

H-10 -11 -12 -13

68 7 5 4 3 2 1(ppm)

(b)

8 7 6 5 4 3 2 1

DMSOH-1

H-6a -6b

H-3 -4 -5

H-2

H-10 -11 -12 -13

(ppm)

(c)

180 160 140 120 100 80 60 40 20

C-1

C-5 -3

C-6C-2 DMSO

C-4

(ppm)

(d)

180 160 140 120 100 80 60 40 20

C-1

C-7 -14

C-4

C-5 -3C-2

C-6DMSO

C-8 -9 -10 -11 -12 -13

(ppm)

(e)

180 160 140 120 100 80 60 40 20

C-7 -14C-1

C-4

C-5 -3

C-6

C-2 DMSO

(ppm)

C-8 -9 -10 -11 -12 -13

(f)





2(C2H2)] 7533336

[C-I3(C3H3)] 8085333 [C-I

4(C4H4)] 7714318 [C-

I5(C5H5)] and 10344433 [C-I









3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734


C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)




1 2 3 4 5 6a 6b


Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080




3(C3H3) and C-NR

5(C5H5)






1H1correlation from





0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




3035404550

60

65

70

75

80

85

90

95

100

105

110

C-I1

C-I2C-I3

C-I4

C-I5

C-I6 C-NR4

(ppm)

(a)

3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002

C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-I2 + C-NR2

C-R1205724 + C-R1205734


C-I3 + C-R1205733C-R1205735

C-I4

C-I6C-NR4

C-R1205731

(ppm)

(b)

(ppm)3035404550

60

65

70

75

80

85

90

95

100

105

110

C-NR6

C-R1205726 + C-R1205736

C-I9984001

C-I9984002C-I9984006

C-R1205721

C-R1205722C-R1205723

C-R1205725

C-R1205732

C-I1 + C-NR1

C-R1205724 + C-R1205734


C-I3 + C-R1205733

C-R1205735

C-R1205731

C-I4

C-I6C-NR4

C-I2 + C-NR2

(c)

(ppm)727476788082

130

132

Aryl group

O OO O

O OO

HO

OR OR

OR OR

OR OR

OR

RO ROROROOR

OH

R =

or H

C1

C6 C5C4

C3C2

C-NR C-I

n = 1 2 3 4

C-R120572C-R120573

n

O

O

O

C

C OH

(d)




1 2 3 4 5 6a 6b


Cellulose (NR)1H 423 298 315 305 316 339 36913C 10365 7377 7707 7054 7718 6150 6150

Cellulose (R120572)1H 489 316 369 331 368 356 37213C 9244 7268 7211 8136 7025 6080 6080

Cellulose (R120573)1H 514 293 325 331 306 356 37213C 10331 7493 7524 8136 7513 6080 6080




3(C3H3) and C-NR

5(C5H5)






1H1correlation from





0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab

0

100

80

60

40

20

Wei

ght (

)

100 200 300 400 500Temperature (∘C)

c

ab



2

(C2H2)] 7211369 [C-R120572

3(C3H3)] and 7025368 [C-


2(C2H2) and C-R120573

5




4(C4H4) and C-R120573

4


6(C6H6)





3(C3H3)] 8074337 [C-I

4

(C4H4)] 7700345 [C-I

5(C5H5)] and 10323434 [C-I

1






6



2(C2H2)]








2




4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





4 Conclusions


Competing Interests


Acknowledgments


References














6rdquo BioEnergy

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Date post:	27-May-2018
Category:	Documents
Upload:	ngonguyet
View:	214 times
Download:	0 times

Research Article Reaction Behavior of Cellulose in the...

Documents