researcharticle full n,n-methylation of 4,4...

Research ArticleFull NN-Methylation of 441015840-Methylenedianilinewith Dimethyl Carbonate A Feasible Access to 441015840-Methylenebis(NN-Dimethylaniline)

Zegang Qiu 1 Kunjie Wang2 Zhiqin Li 1 Tao Li1 Jinhao Bai1 Chanjuan Yin1

Xiushen Ye3 and Haining Liu3

1College of Chemistry and Chemical Engineering Xirsquoan Shiyou University Xirsquoan 710065 China2Xirsquoan Aerospace Composites Research Institute Xirsquoan 710025 China3The Qinghai Institute of Salt Lakes The Chinese Academy of Sciences Xining 810008 China

Correspondence should be addressed to Zhiqin Li lizhiqinxsyueducn

Received 25 December 2017 Accepted 14 February 2018 Published 18 April 2018

Academic Editor Bartolo Gabriele

Copyright copy 2018 Zegang Qiu et al This 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

The full NN-methylation of 441015840-methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated The yield of themajor product 441015840-methylene bis(NN-dimethylaniline) (MBDMA) reached as high as 97 over NaY catalyst at 190∘C for 6 hThecatalyst could be used for two more times with acceptable MBDMA yields higher than 90The main by-products were identifiedas three N-methylated derivatives Surprisingly the formation of the N-methoxycarbonylation product was extremely restrainedwhich could be produced in high yields of 98 on zinc acetate catalyst Furthermore the reaction pathway to the major productMBDMAwas proposed Finally a feasible synthetic route of 441015840-methylene bis(NN-dimethylaniline) (MBDMA) was establishedfeaturing a high yield mild reaction conditions and simple operations

1 Introduction

The reaction of 441015840-methylenedianiline (MDA) with dim-ethyl carbonate (DMC) produced 441015840-methylenedimethyld-iphenylcarbamate (MDC) in high yield of 98 under thecatalysis of the zinc acetate as described in literatures [12] and our previous work [3] Furthermore the results ofour research demonstrated that the three main by-productsformed during the N-methoxycarbonylation reaction wereall N-methylated derivatives [3] Such results revealed thatthe N-methoxycarbonylation and the N-methylation weretwo competitive processes in the reaction of MDA withDMC So far almost all of the research focused on theN-methoxycarbonylation process between MDA and DMCwhich was always treated as the main reaction accordinglythe details of N-methylation process were still left unknownThus we moved our focus to the N-methylation reaction ofMDA with DMC and tried to make it to be the predominant

reaction Two possible N-methylation reaction pathwayswere listed in Scheme 1 Our purpose was to produce441015840-methylene bis(NN-dimethylaniline) (MBDMA)or 441015840-methylene-bis-(N-methylaniline) (MBMA) or the both inhigh yield

Aforementioned MBDMA has found many applicationsin many fields For example it can be used as an intermediatein dye manufacture and as an analytical reagent in thedetermination of lead iodide bromide and so forth [4ndash6]In addition it can also form charge-transfer complex withphenazine and its derivatives [7ndash9] Commercially MBDMAwas synthesized by condensation of NN-dimethyl anilinewith formaldehyde over homogeneous acid catalysts [10]However this route suffered from some problems such asprocess complexity equipment corrosion and environmentalpollution caused by the waste produced Recently ionicliquid was used in the reaction of NN-dimethylaniline withtetrachloromethane to produce MBDMA in the highest yield

HindawiJournal of ChemistryVolume 2018 Article ID 4627903 10 pageshttpsdoiorg10115520184627903

2 Journal of Chemistry

(DMC)(MDA)

CO

NaY

N N(MBDMA)

(MBMA)

（2

（3（

（3

（3（3

（（3 + （3（ + 2

（3 + （3（ + 2

（3 （3（2

+

Scheme 1 Two possible N-methylation reaction pathways of MDA with DMC

of 61 [11] Also the structure and vibrational spectra ofMBDMA were investigated by the DFT-B3LYP and ab initioMP2 calculations [12]

The reactant MDA has been produced on industrialscale while DMC is a versatile methylating or methoxycar-bonylating reagent for the green synthesis of many organics[13] The N-methylation of primary amines with DMC hasbeen extensively investigated [14ndash20] in particular a generalprotocol for the reductive N-methylation of primary andsecondary amines using dimethyl carbonate and molecularhydrogen was developed recently [21] It is worth noting thatthe mono-N-methylation of primary aromatic amines withdimethyl carbonate could occur in high selectivity [15 16]However the NN-methylation or mono-N-methylation ofdiamineswithDMChas not been describedTherefore worksshould be done to figure out how and to what extent the NN-methylation or mono-N-methylation reaction of diamineswith DMC occurs Furthermore a successful synthesis ofMBDMA from MDA and DMC should not only set anexample of the NN-methylation reaction of diamine withDMC but also provide a new alternative route to MBDMA

In this paper 441015840-methylene bis(NN-dimethylaniline)(MBDMA) was obtained by the NN-methylation reactionof 441015840-methylenedianiline (MDA) with dimethyl carbonate(DMC) in high yield under the catalysis of NaY zeolite Alsothe main by-products formed during the NN-methylationprocess were identified The reusability of NaY catalyst waschecked Furthermore the formation mechanism of the N-methylated compounds was discussed However the effort toproduce MBMA failed and the details will be provided laterin this paper

2 Experimental

21 Chemicals 44-Methylenedianiline (MDA) was com-mercially available and usedwithout further treatment DMCof analytically pure grade was purified by distillation beforeuseThe H120573 ZSM-5 NaY NaX andMCM-41 were commer-cial products from theCatalyst Plant ofNankai and theywerecalcined at 500∘C for 2 h before use

22 Instrumentation High performance liquid chromatog-raphy (HPLC) analyses were performed on a Shimadzu

LC (Japan) equipped with a SPD-10Avp detector A Shim-pack Vp-ODS column (150 times 46mm) and a mobile phaseCH3OHH

2O 6040 (volume) were used 1H NMR spectra

were recorded on a Bruker drx-300 instrument (Germany)Chemical shifts were reported in ppm (120575-scale) relative tointernal standard TMS CDCl

3was used as a solvent IR

spectra (cmminus1) were collected with a Thermo Nicolet 380FT-IR (USA) X-ray diffraction (XRD) measurements wereperformed on a Bruker D8 Advance X-Ray Diffractometer(Germany) with a CuK120572 radiation source Elemental analysiswas performed with an Elementar Vario EL (Germany)HPLC coupled with mass spectrometry (HPLCMS) wasrun on a Waters HPLCMS system equipped with a Watersalliance 2695 HPLC pump a Waters 2996 photodiode arraydetector and a Waters micromass ZQ-4000 mass spectrom-eter A Waters symmetry C18 column (150mm times 211mm3 120583m) and amobile phase CH

3OHH

2O6545 (volume) were

usedTheflow rate of themobile phasewas 3mLminThe ionsource temperature was 130∘C and the cone temperature was20∘C N

2adsorptionndashdesorption isotherms were recorded

on a Tristar-3000 Micromeritics volumetric apparatus Thespecial surface area was calculated according to the BETisothermal equation The temperature-programmed desorp-tion of ammonia (NH

3-TPD) was carried out About 100mg

sample (20ndash40 mesh) was pretreated at 500∘C for 2 h ina quartz tube in nitrogen stream Then it was cooled to100∘C and adsorbed ammonium for 10min The desorptionof ammonium was conducted at a heating rate of 10∘Cminin nitrogen flow (30mLmin)The desorbed ammonium wasmonitored by a thermal conductivity detector (TCD)

23 Reaction All the reactions were conducted in a 100mLstainless autoclave with a magnetic stirrer MDA DMCand catalysts were charged into the reactor The air in theautoclave was fully replaced with nitrogen to guarantee thatthe reaction was carried out under the inert atmosphere Themixture was then stirred constantly and heated to a selectedtemperature for certain hours When the reaction was com-pleted the autoclave was cooled down to room temperatureThe solid-liquid mixture obtained was separated into twoparts by filtration a white powder (zeolite catalyst) and aclear light yellow liquid The liquid was then analyzed withShimadzu HPLC using naphthalene as an internal standard

Journal of Chemistry 3

Table 1 Formation of MBDMA over various catalysts

CatalystsMDA MBDMA

Conversion

Selectivity

Yield

None 612 None NoneH120573 618 None NoneZSM-5 622 None NoneNaX 100 287 287NaY 100 911 911MCM-41 864 None NoneReaction Conditions DMC 270 g (030mol) MDA 198 g (001mol) catalyst198 g reaction time 6 h and reaction temperature 180∘C

The conversion of MDA and the yield of MBDMA werecalculated by HPLC

24 Characterization of MBDMA A MBDMA yield of 97(247 g 00097mol) and a MDA conversion of 100 wereattained when a mixture of MDA (198 g 001mol) DMC(270 g 030mol) and NaY (198 g) was stirred at 190∘C for6 h In this case the liquid was a mixture consisting ofMBDMA DMC and a tiny amount of by-products Afterdistilling off DMC from the mixture a light yellow solid wasobtained The solid was further purified by recrystallizationfrom alcohol and a crystalline compound was obtainedwhich was identified as MBDMA

Characterization data of MBDMA were listed as fol-lows 441015840-Methylene bis(NN-dimethylaniline) (MBDMA)IR (KBr) ]cmminus1 3448 2886 2804 1613 1564 1521 1480 14441355 1342 1309 1231 1189 1168 1124 1071 949 829 795 568508 1H NMR (300MHz CDCl

3) 120575 288 (s 12H CH

3) 379

(s 2H CH2) 666ndash668 (m 4H Ar-H) 703ndash706 (m 4H

Ar-H) MS mz observed 2553 [M]+ + 1 C17H22N2[M]+

+ 1 requires 2554 For C17H22N2(2544) found 7994 C

863 H 1073 N requires 8027 C 872 H 1101 N

25 The Analysis of By-Products In order to obtain a suitableamount of by-products for analyzing a mixture of MDA(198 g 001mol) DMC (270 g 030mol) and NaY (198 g)was stirred at 150∘C for 6 h attaining aMBDMAyield of 114and a MDA conversion of 100 The liquid obtained afterfiltering off the catalyst was then analyzed with HPLCMS

3 Results and Discussion

31 Catalyst Function As the zeolites exhibited effectivecatalytic activity to themethylation reaction of some aromaticamines [16 17 22ndash24] several different zeolites such as H120573H-ZSM-5 NaX NaY and MCM-41 were chosen to catalyzethe reaction of MDAwith DMC in order to obtain MBDMAas shown in Table 1 Disparate catalytic performances wereobserved H120573 and H-ZSM-5 exhibited almost no activityMCM-41 facilitated the conversion of MDA but showed noselectivity to the MBDMA NaX had better activity to theconversion of MDA but poor selectivity to MBDMA NaY

MBDMA

3

2

1

5 10 15 20 25 30 35 40 45 50 550Retention time (min)

Figure 1 The liquid chromatogram of the filtrate obtained after thereaction of MDA with DMC

had the best activity and selectivity among the chosen zeo-lites Under the catalysis of NaY MDA could be completelytransformed andMBDMA selectivity reached a high value of911 Such results revealed that the formation of MBDMAdepended on the properties of the catalysts The propertiessuch as the pores and structures of H120573 ZSM-5 NaX NaYandMCM-41 are apparently different H120573 andH-ZSM-5 havemicropores but have no cages and NaX and NaY possessedmicropores as well as octahedral zeolite cages whileMCM-41possesses mesopores and orderly lined hexagonal channelsTherefore it could be broadly inferred that the formationof MBDMA is associated with the pore sizes and structuresAs NaY exhibited outstanding catalytic performance furtherinvestigation was made to improve the yield of MBDMA andto clarify the reaction mechanism

32 The By-Products Formed over NaY To help to compre-hend the formation mechanism of the main product the by-products in the reaction of MDA with DMC over NaY wereanalyzed by HPLCMS obtaining the liquid chromatogram(Figure 1) and the MS spectra (Figure 2) Three by-productsincluding 1 2 and 3 were detected as shown in Figure 1The molecular weights of compounds 1 2 and 3 could beobtained by analyzing the MS spectra which were listed inTable 2 The possible configurations of 1 2 and 3 could besketched (shown in Table 2) based on the molecular weightsand the known compounds (MDA and DMC) added in thereaction system As we can see compounds 1 and 3 only cor-responded to 1a and 3a respectively Thus the structures ofcompounds 1 and 3were clearly identified (shown in Table 2)by combining the analyses of the fragment ions in thecorresponding MS spectra However the molecular weightsof compound 2 corresponded to two possible configurations2a and 2b Therefore meticulous analyses to MS spectra of2 in Figure 2(b) were done to further identify its structureFortunately a key ion 4 at mz 106 (Figure 2(b)) was foundand it could be generated by 2a but not by 2b Furthermoremost of the fragment ions in Figure 2(b) could be ascribedto compound 2a Thus compound 2 was confirmed to be 2aSo far the by-products 1 2 and 3 were finally identified as


213106

136181

198

211

150 200 250 300100

0

2

4

6

8

10

12

14

16

18

20

mz

Inte

nsity

times10minus5c

ps

(a)

227

106120

212225

150 200 250 300100

NHCH3

0

1

2

3

4

5

6

7

8

9

mz

Inte

nsity

times10minus6c

ps

(b)

106 212

226

239

241

120135

150 200 250 300100

00

05

10

15

20

25

30

35

40

45

50

mz

Inte

nsity

times10minus6c

ps

(c)

Figure 2 MS spectra of the by-products 1 2 and 3 Subfigures (a) (b) and (c) present the MS spectra of the pseudomolecular ions ofcompounds 1 2 and 3 respectively 4 stands for the ion with anmz value of 106

three N-methylated derivatives with different degrees of N-methylation as shown in Table 2

33 The Optimum Reaction Conditions for the Formationof MBDMA The effects of the reaction conditions includ-ing the reaction temperature the reaction time the NaYamount and the DMCMDAmolar ratio on the formation ofMBDMA over NaY zeolites were investigated and the resultswere displayed in Table 3 and Figures 3 and 4

The NaY amount was expressed by NaYDMC weightratio It was found that a ratio higher than 007 was needed towarrant the high MBDMA yields (Table 3) In this reactionDMC was taken in excess to fully utilize MDA and facilitatethe product formation DMC served as both the reagentand the solvent The optimum DMCMDA molar ratio was

30 (Table 3) The excess DMC distilling from the reactionmixture could be recycled

As shown in Table 3 when the reaction temperature was120∘C the conversion of MDA was at a low value of 612while the main product MBDMA was not detected In thiscase the converted MDA mainly produced by-products 1and 2 (Figure 3) As the reaction temperature was increasedthe conversion of MDA and the yield of MBDMA wereaccordingly increased When the reaction temperature roseto 160∘C the conversion ofMDA attained 100 however theselectivity of MBDMA was only 392 Such poor MBDMAselectivity could be mostly attributed to the formation ofthe by-products 2 and 3 (Figure 3) When the reactiontemperature was going on increased to 190∘C the selectivityof MBDMA reached to the highest value of 974 on the


Table 2 The molecular weights and structures of by-products 1 2 and 3

Compound Molecularweights Identified structures Possible configurations

1 212

（2 （（3 1a（2 （（3

2 226 （3（（（3

2a

N2b（2

（（3（3（

（3

（3

3 240 N （（3

（3

（3

NCH

3a（（3

（3

32

MBDMA

MDA 1

190∘C

120∘C

150∘C

160∘C

170∘C

4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 640Retention time (min)

Figure 3 Liquid chromatograms obtained after the reactionbetween MDA and DMC under different temperatures Reactionconditions DMC 270 g (030mol) MDA 198 g (001mol) NaY198 g and reaction time 6 h119898(NaY)119898(DMC) (gg) = 0071

contrary the unwanted by-products were minimized to verysmall amount Further increasing the reaction temperature to200∘Ccould not improve the selectivity ofMBDMAanymoreThus the optimum reaction temperature should be con-trolled around 190∘C Furthermore the yields of by-products1 2 and 3 sequentially increased and then dropped one byone such trend could effectively prove that the MBDMAwasformed via the gradually N-methylated reaction

As we can see from Table 3 when the reaction wascarried out for 05 hMDAhad been fully converted howeverthe MBDMA selectivity was at a low value of 266 thiswas mainly because of the formation of by-products 2 and3 (Figure 4) As the reaction time prolonged to 2 h the

MDA

1

02 h

10 20 30 40 50 600Retention time (min)

MBDMA

32

60 h

20 h

05 h

Figure 4 Liquid chromatograms obtained after the reactionbetween MDA and DMC under different reaction times Reactionconditions DMC 270 g (030mol) MDA 198 g (001mol) NaY198 g and reaction temperature 190∘C 119898(NaY)119898(DMC) (gg) =0071

MBDMA selectivity rose to 651 in this case the pre-dominant by-product was 3 (Figure 4) As the reaction timereached to 6 h the highest MBDMA selectivity of 974 wasachieved with a tiny amount of by-products formed A longerreaction time could not improve the MBDMA selectivityanymore So the optimum reaction time should be controlledaround 6 h The changing trend of the yields of by-products1 2 and 3 over the reaction time was very similar to thatover the reaction temperature This further proved that theMBDMA was formed following the gradually N-methylatedreaction route

34 The Reusability of the Catalyst NaY In order to checkthe reusability the used NaY catalyst was filtered out dried


Table 3 The effect of the reaction conditions on the formation of MBDMA over NaY zeolites

Run Reactiontemperature∘C

Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974

Table 4 Reuse of NaY zeolite catalyst

Run MDA conversion () MBDMA yield ()1 100 972 100 943 100 90Reaction Conditions DMC 270 g (030mol) MDA 198 g (001mol) NaY198 g reaction time 6 h and reaction temperature 190∘C119898(NaY)119898(DMC)(gg) = 0071

in the room temperature and employed in the next run TheNaY catalyst was reused for twomore times and the results arelisted in Table 4 As it is shown the reused NaY catalysts gaveexcellentMDAconversion of 100 andMBDMAyield higherthan 90 However MBDMA yield gradually decreasedfrom 97 to 90 with the increase of the used times ofNaY To figure out the reason for such decrease the reusedNaY catalysts were characterized by XRD IR NH

3-TPD N

2

adsorption and elemental analysisFigure 5 shows the XRD patterns of the fresh and

reused NaY catalysts All the samples similarly showedtypical diffraction peaks of Y zeolite [25] indicating that theframework structures of the reused catalysts were essentiallyretained

(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)

Figure 5 XRD spectra of fresh and reused NaY catalysts (a) FreshNaY (b) NaY after used for the first time (c) NaY after used for thesecond time

Figure 6 displays the IR spectra Clearly all the samplesexhibited similar peaks at the same wave numbers of about470 cmminus1 1030 cmminus1 1100 cmminus1 1650 cmminus1 and 3450 cmminus1The wave numbers of 470 cmminus1 1030 cmminus1 1100 cmminus1 and


(c)

(b)

(a)

3600 3200 2800 2400 2000 1600 1200 800 4004000Wave numbers (cmminus1)

0102030405060708090

100

Tran

smitt

ance

()

Figure 6 IR spectra of fresh and reused NaY catalysts (a) FreshNaY (b) NaY after used for the first time (c) NaY after used for thesecond time

(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)

Figure 7 NH3-TPD profiles of fresh and reused NaY catalysts (a)

Fresh NaY (b) NaY after used for the first time (c) NaY after usedfor the second time

1650 cmminus1 were assigned to the framework vibrations ofY zeolite [25 26] and the 3450 cmminus1 was assigned to thevibrations of the surface hydroxyl groups on Y zeolite[26] The presence of those similar peaks further provedthat the framework structures of the reused catalysts wereessentially retained However the intensity of these peaksgradually attenuated with the reuse times of the NaY catalystsincreasing which was consistent with the decreasing trend ofthe MBDMA yield The attenuation of the intensity of theseIR peaksmight be caused by the deposition of the compoundson the catalyst from the reaction mixture (see Table 5)

Figure 7 presents the NH3-TPD profiles Generally the

desorption of NH3at low temperature (lt200∘C) was related

to weak acid sites while those atmedium (200∘Cndash400∘C) andhigh temperature (gt400∘C) were correlated with moderateand strong acid sites The fresh NaY exhibited a peak ofweak acid around 190∘C while the according peaks ofreused NaY catalysts shifted to the low temperatures inparticular the peak shift of the NaY catalysts reused for threetimes was rather obvious Such shifts revealed that the acid

Table 5 Elemental analysis and N2adsorption of fresh and reused

NaY catalysts

Run Cwt Nwt Surface aream2g

Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015

strength of reused NaY was gradually weakened with theused times increasing Apparently this weakening trend ofthe acid strength of the NaY catalysts was consistent with thedecreasing trend of the MBDMA yield Thus it is reasonableto infer that the weakening acid strength of the NaY was afactor leading to the decreasing of the MBDMA yield

The elemental analysis results of fresh and reused NaYcatalysts are listed in Table 5 The content of the C in reusedNaY catalysts sharply increased compared to that in the freshcatalysts demonstrating the deposition of the compounds onthe catalyst from the reaction mixture occurred Howeverthese depositing compounds cannot be detected by XRDand IR Apparently the deposition of the compounds wouldoccupy some surfaces and pores causing the decrease ofthe surface area and pore volume (Table 5) Accordinglysome effective active sites would be covered and the reactionplace would somewhat shrink consequently resulting in thedecreasing of the MBDMA yield

Due to a comprehensive understanding of the results ofXRD IR NH

3-TPD N

2adsorption and elemental analysis

a full conversion of MDA was guaranteed by the essentialretaining of the framework structures of the reused catalystsThe decrease of the MBDMA yield could be attributed totwo factors (1) the acid strength of reused NaY graduallyweakened and (2) the deposition of the compounds fromthe reaction mixture covered some effective active sites andsomewhat shrank the reaction space

35 The Mechanism of N-Methylation Reaction of MDA withDMC TheN-methoxycarbonylation and the N-methylationwere two competitive processes in the reaction of MDA withDMC As described above the full N-methylation of MDAwith DMC occurred predominantly under the catalysis ofNaY while the N-methoxycarbonylation process was greatlyrestrained obtaining a yield of the MBDMA as high as 97Such result presented a sharp contrast with the reaction ofMDA with DMC catalyzed by zinc acetate [1ndash3] in whichthe N-methoxycarbonylation was the predominant processApparently catalysts played a key role in the reaction ofMDAwith DMCThe zinc acetate effectively activated the carbonylgroup of DMC and thus N-methoxycarbonylation productwas easily formed by the direct attack of amino group ofMDAon the carbonyl carbon of DMC [3 27]

However the reaction of MDA with DMC on NaY wasmore complicated than that on zinc acetate NaY can activatethe molecule of DMC [20] which basically endowed it withenough activity to catalyze the reaction of MDA with DMCHowever this cannot guarantee a directional selectivity to a


(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3

Scheme 2 Two possible pathways of the N-methylation process of MDA with DMC in the presence of NaY

particular product which was closely related to its particularpore structures

Generally the N-methylation reactions of aromaticamines with DMC may follow two possible pathways [16 1827] (i) the amino group of aromatic amine directly attacksthemethoxy group ofDMC (ii)The amino group of aromaticamine firstly attacks the carbonyl group of DMC producingN-methoxycarbonylation intermediate And then the aminogroup of this intermediate further attacks themethyl ofDMCobtaining highly selective mono-N-methylated products Itshould be noted that the selective mono-N-methylationreaction occurs in the octahedral zeolite cages of NaY inpathway (ii) [16 18] making the particular pore structures ofNaY to be a decisive factor in the selective synthesis of mono-N-methylated derivatives

As mentioned above N-methylation process of MDAwith DMC occurred gradually over the NaY catalyst succes-sively forming partially N-methylated products 1 2 and 3before the final product MBDMA was formed In contrastthe peak of MDC was not detected by HPLC MDC was

the N-methoxycarbonylated intermediate which had to beformed to selectively produce mono-N-methylated productof compound 1 (MDMA) according to the pathway (ii)(shown in Scheme 2) Such results revealed that the N-methylation process of MDA with DMC obeyed the pathway(i) which is presented in Scheme 2 In this pathway (i) a highselectivity to the mono-N-methylated product of MDMAcould not be achieved

4 Conclusion

In this work an access to 441015840-methylene bis(NN-dim-ethylaniline) (MBDMA) via NN-methylation of 441015840-meth-ylenedianiline (MDA) with dimethyl carbonate (DMC) overNaY catalyst was reported This process features a high yieldof the required product under mild reaction conditions andsets an example of the NN-methylation reaction of diaminewith DMC The reusability of the catalyst and the simpleoperations are also the advantages of this method Alsoa reasonable reaction pathway was proposed based on the


identification of the by-products and the tracing analysis ofthe transformation of the by-products during the reactionprocess Furthermore the implementation of such processproved that the selectivity to the two competitive processesN-methylation and N-methoxycarbonylation can be controlledby changing the catalysis systems and the reaction conditions

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

This work is supported by the Chinese National NaturalScience Foundation (no 51403229 and no 21606177) and theScientific Research Training Program of Xirsquoan University ofPetroleum

References

[1] I Vauthey F Valot C Gozzi F Fache and M LemaireldquoAn environmentally benign access to carbamates and ureasrdquoTetrahedron Letters vol 41 no 33 pp 6347ndash6350 2000

[2] T Baba A Kobayashi T Yamauchi et al ldquoCatalytic methoxy-carbonylation of aromatic diamines with dimethyl carbonate totheir dicarbamates using zinc acetaterdquo Catalysis Letters vol 82no 3-4 pp 193ndash197 2002

[3] Z Qiu J Wang M Kang Q Li and X Wang ldquoForma-tion of intermediate and by-products in synthesis of 441015840-methylenedimethyldiphenylcarbamaterdquo Catalysis Letters vol124 no 3-4 pp 243ndash249 2008

[4] W Buchberger ldquoDetermination of iodide and bromide by ionchromatography with post-column reaction detectionrdquo Journalof Chromatography A vol 439 no 1 pp 129ndash135 1988

[5] L Su J Li HMa and G Tao ldquoDetermination of trace amountsof manganese in natural waters by flow injection stopped-flowcatalytic kinetic spectrophotometryrdquo Analytica Chimica Actavol 522 no 2 pp 281ndash288 2004

[6] R Periasamy S Kothainayaki and K Sivakumar ldquoInvestigationon inter molecular complexation between 441015840-methylene-bis(NN-dimethylaniline) and 120573-cyclodextrin Preparation andcharacterization in aqueous medium and solid staterdquo Journal ofMolecular Structure vol 1080 pp 69ndash79 2014

[7] S D Choudhury and S Basu ldquoCaging of phenazine by 441015840-bis(dimethylamino)diphenylmethane A comparative studywith phenazine-NN-dimethylanilinerdquo Chemical Physics Let-ters vol 383 no 5-6 pp 533ndash536 2004

[8] S D Choudhury and S Basu ldquoExploring the extent of magneticfield effect on intermolecular photoinduced electron transferin different organized assembliesrdquo The Journal of PhysicalChemistry A vol 109 no 36 pp 8113ndash8120 2005

[9] D Dey A Bose M Chakraborty and S Basu ldquoMag-netic field effect on photoinduced electron transfer betweendibenzo[ac]phenazine and different amines in acetonitrile -water mixturerdquoThe Journal of Physical Chemistry A vol 111 no5 pp 878ndash884 2007

[10] W L Borkowski and E C Wagner ldquoMethylation of aromaticamines by the wallach methodrdquo The Journal of Organic Chem-istry vol 17 no 8 pp 1128ndash1140 1952

[11] Y Wang ldquoAn experimental and theoretical study on the prepa-ration of 441015840-methylene-bis(NN-dimethylaniline) in ionic liq-uidrdquo Journal of Physical Organic Chemistry vol 29 p p 2762016

[12] H Badawi ldquoA comparative study of the structure andvibrational spectra of diphenylmethane the carcinogen 441015840-methylenedianiline and 441015840-methylene-bis(NN-dimethylan-iline)rdquo Spectrochimica Acta Part A Molecular and BiomolecularSpectroscopy vol 109 p 213 2013

[13] P Tundo and M Selva ldquoThe chemistry of dimethyl carbonaterdquoAccounts of Chemical Research vol 35 no 9 pp 706ndash716 2002

[14] K Sreekumar T M Jyothi T Mathew M B Talawar SSugunan and B S Rao ldquoSelective N-methylation of anilinewith dimethyl carbonate over Zn(1-x)Co(x)Fe2O4 (x = 0 0205 08 and 10) type systemsrdquo Journal of Molecular Catalysis AChemical vol 159 no 2 pp 327ndash334 2000

[15] NNagaraju andGKuriakose ldquoActivity of amorphousV-AlPO4and Co-AlPO4 in the selective synthesis of N-monoalkylatedaniline via alkylation of aniline with methanol or dimethylcarbonaterdquoNew Journal of Chemistry vol 27 no 4 pp 765ndash7682003

[16] M Selva A Bomben P Tundo and J Chem ldquoSelectivemono-N-methylation of primary aromatic amines by dimethylcarbonate over faujasite X- and Y-type zeolitesrdquo Journal of theChemical Society Perkin Transactions 1 no 7 p 1041 1997

[17] M Selva P Tundo and A Perosa ldquoReaction of primaryaromatic amines with alkyl carbonates over NaY faujasite Aconvenient and selective access to mono-N-alkyl anilinesrdquoTheJournal of Organic Chemistry vol 66 no 3 pp 677ndash680 2001

[18] M Selva P Tundo and A Perosa ldquoMono-N-methylation ofprimary amines with alkyl methyl carbonates over Y faujasites2 Kinetics and selectivityrdquo The Journal of Organic Chemistryvol 67 no 26 pp 9238ndash9247 2002

[19] M Selva P Tundo and A Perosa ldquoReaction of Functional-ized Anilines with Dimethyl Carbonate over NaY Faujasite3 Chemoselectivity toward Mono-N-methylationrdquo Journal ofOrganic Chemistry vol 68 no 19 p 7374 2003

[20] M Selva P Tundo and T Foccardi ldquoMono-N-methylation offunctionalized anilines with alkyl methyl carbonates over NaYfaujasites 4 Kinetics and selectivityrdquo The Journal of OrganicChemistry vol 70 no 7 pp 2476ndash2485 2005

[21] A J Cabrero R Adam K Junge andM Beller ldquoA general pro-tocol for the reductive N-methylation of amines using dimethylcarbonate and molecular hydrogen mechanistic insights andkinetic studiesrdquo Catalysis Science and Technology vol 6 no 22p 7956 2016

[22] I I Ivanova E B Pomakhina A I Rebrov W Wang MHunger and J Weitkamp ldquoMechanism of Aniline Methylationon Zeolite Catalysts Investigated by In Situ 13C NMR Spec-troscopyrdquo Kinetics and Catalysis vol 44 no 5 pp 701ndash7092003

[23] T Esakkidurai and K Pitchumani ldquoZeolite-promoted selectivemono-N-methylation of aniline with dimethyl carbonaterdquo Jour-nal of Molecular Catalysis A Chemical vol 218 no 2 pp 197ndash201 2004

[24] O A Ponomareva P A Shaposhnik M V Belova1 B AKolozhvari and I I Ivanova ldquoNovelmethod for the preparationof Cs-containing FAU(Y) catalysts for aniline methylationrdquoFrontiers of Chemical Science and Engineering vol 12 no1 pp 70ndash76 2018 httpslinkspringercomarticle1010072Fs11705-017-1694-3


[25] D Guo B Shen Y Qin et al ldquoUSY zeolites with tunablemesoporosity designed by controlling framework Fe contentand their catalytic cracking propertiesrdquoMicroporous and Meso-porous Materials vol 211 pp 192ndash199 2015

[26] R Xu and W Pang Chemistry-zeolites and porous materialsScience press Beijing China 2004

[27] T Baba A Kobayashi Y Kawanami et al ldquoCharacteristicsof methoxycarbonylation of aromatic diamine with dimethylcarbonate to dicarbamate using a zinc acetate catalystrdquo GreenChemistry vol 7 no 3 pp 159ndash165 2005

TribologyAdvances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawiwwwhindawicom Volume 2018

SpectroscopyInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

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SpectroscopyAnalytical ChemistryInternational Journal of


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BioMed Research International Electrochemistry

International Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom


(DMC)(MDA)

CO

NaY

N N(MBDMA)

(MBMA)

（2

（3（

（3

（3（3

（（3 + （3（ + 2

（3 + （3（ + 2

（3 （3（2

+

Scheme 1 Two possible N-methylation reaction pathways of MDA with DMC

of 61 [11] Also the structure and vibrational spectra ofMBDMA were investigated by the DFT-B3LYP and ab initioMP2 calculations [12]

The reactant MDA has been produced on industrialscale while DMC is a versatile methylating or methoxycar-bonylating reagent for the green synthesis of many organics[13] The N-methylation of primary amines with DMC hasbeen extensively investigated [14ndash20] in particular a generalprotocol for the reductive N-methylation of primary andsecondary amines using dimethyl carbonate and molecularhydrogen was developed recently [21] It is worth noting thatthe mono-N-methylation of primary aromatic amines withdimethyl carbonate could occur in high selectivity [15 16]However the NN-methylation or mono-N-methylation ofdiamineswithDMChas not been describedTherefore worksshould be done to figure out how and to what extent the NN-methylation or mono-N-methylation reaction of diamineswith DMC occurs Furthermore a successful synthesis ofMBDMA from MDA and DMC should not only set anexample of the NN-methylation reaction of diamine withDMC but also provide a new alternative route to MBDMA

In this paper 441015840-methylene bis(NN-dimethylaniline)(MBDMA) was obtained by the NN-methylation reactionof 441015840-methylenedianiline (MDA) with dimethyl carbonate(DMC) in high yield under the catalysis of NaY zeolite Alsothe main by-products formed during the NN-methylationprocess were identified The reusability of NaY catalyst waschecked Furthermore the formation mechanism of the N-methylated compounds was discussed However the effort toproduce MBMA failed and the details will be provided laterin this paper

2 Experimental

21 Chemicals 44-Methylenedianiline (MDA) was com-mercially available and usedwithout further treatment DMCof analytically pure grade was purified by distillation beforeuseThe H120573 ZSM-5 NaY NaX andMCM-41 were commer-cial products from theCatalyst Plant ofNankai and theywerecalcined at 500∘C for 2 h before use

22 Instrumentation High performance liquid chromatog-raphy (HPLC) analyses were performed on a Shimadzu

LC (Japan) equipped with a SPD-10Avp detector A Shim-pack Vp-ODS column (150 times 46mm) and a mobile phaseCH3OHH

2O 6040 (volume) were used 1H NMR spectra

were recorded on a Bruker drx-300 instrument (Germany)Chemical shifts were reported in ppm (120575-scale) relative tointernal standard TMS CDCl

3was used as a solvent IR

spectra (cmminus1) were collected with a Thermo Nicolet 380FT-IR (USA) X-ray diffraction (XRD) measurements wereperformed on a Bruker D8 Advance X-Ray Diffractometer(Germany) with a CuK120572 radiation source Elemental analysiswas performed with an Elementar Vario EL (Germany)HPLC coupled with mass spectrometry (HPLCMS) wasrun on a Waters HPLCMS system equipped with a Watersalliance 2695 HPLC pump a Waters 2996 photodiode arraydetector and a Waters micromass ZQ-4000 mass spectrom-eter A Waters symmetry C18 column (150mm times 211mm3 120583m) and amobile phase CH

3OHH

2O6545 (volume) were

usedTheflow rate of themobile phasewas 3mLminThe ionsource temperature was 130∘C and the cone temperature was20∘C N

2adsorptionndashdesorption isotherms were recorded

on a Tristar-3000 Micromeritics volumetric apparatus Thespecial surface area was calculated according to the BETisothermal equation The temperature-programmed desorp-tion of ammonia (NH

3-TPD) was carried out About 100mg

sample (20ndash40 mesh) was pretreated at 500∘C for 2 h ina quartz tube in nitrogen stream Then it was cooled to100∘C and adsorbed ammonium for 10min The desorptionof ammonium was conducted at a heating rate of 10∘Cminin nitrogen flow (30mLmin)The desorbed ammonium wasmonitored by a thermal conductivity detector (TCD)

23 Reaction All the reactions were conducted in a 100mLstainless autoclave with a magnetic stirrer MDA DMCand catalysts were charged into the reactor The air in theautoclave was fully replaced with nitrogen to guarantee thatthe reaction was carried out under the inert atmosphere Themixture was then stirred constantly and heated to a selectedtemperature for certain hours When the reaction was com-pleted the autoclave was cooled down to room temperatureThe solid-liquid mixture obtained was separated into twoparts by filtration a white powder (zeolite catalyst) and aclear light yellow liquid The liquid was then analyzed withShimadzu HPLC using naphthalene as an internal standard



CatalystsMDA MBDMA

Conversion

Selectivity

Yield





3) 120575 288 (s 12H CH

3) 379




863 H 1073 N requires 8027 C 872 H 1101 N




MBDMA

3

2

1






213106

136181

198

211

150 200 250 300100

0

2

4

6

8

10

12

14

16

18

20

mz

Inte

nsity

times10minus5c

ps

(a)

227

106120

212225

150 200 250 300100

NHCH3

0

1

2

3

4

5

6

7

8

9

mz

Inte

nsity

times10minus6c

ps

(b)

106 212

226

239

241

120135

150 200 250 300100

00

05

10

15

20

25

30

35

40

45

50

mz

Inte

nsity

times10minus6c

ps

(c)










1 212

（2 （（3 1a（2 （（3

2 226 （3（（（3

2a

N2b（2

（（3（3（

（3

（3

3 240 N （（3

（3

（3

NCH

3a（（3

（3

32

MBDMA

MDA 1

190∘C

120∘C

150∘C

160∘C

170∘C





MDA

1

02 h


MBDMA

32

60 h

20 h

05 h







Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974




3-TPD N

2



(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)




(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls






CatalystsMDA MBDMA

Conversion

Selectivity

Yield





3) 120575 288 (s 12H CH

3) 379




863 H 1073 N requires 8027 C 872 H 1101 N




MBDMA

3

2

1






213106

136181

198

211

150 200 250 300100

0

2

4

6

8

10

12

14

16

18

20

mz

Inte

nsity

times10minus5c

ps

(a)

227

106120

212225

150 200 250 300100

NHCH3

0

1

2

3

4

5

6

7

8

9

mz

Inte

nsity

times10minus6c

ps

(b)

106 212

226

239

241

120135

150 200 250 300100

00

05

10

15

20

25

30

35

40

45

50

mz

Inte

nsity

times10minus6c

ps

(c)










1 212

（2 （（3 1a（2 （（3

2 226 （3（（（3

2a

N2b（2

（（3（3（

（3

（3

3 240 N （（3

（3

（3

NCH

3a（（3

（3

32

MBDMA

MDA 1

190∘C

120∘C

150∘C

160∘C

170∘C





MDA

1

02 h


MBDMA

32

60 h

20 h

05 h







Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974




3-TPD N

2



(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)




(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





213106

136181

198

211

150 200 250 300100

0

2

4

6

8

10

12

14

16

18

20

mz

Inte

nsity

times10minus5c

ps

(a)

227

106120

212225

150 200 250 300100

NHCH3

0

1

2

3

4

5

6

7

8

9

mz

Inte

nsity

times10minus6c

ps

(b)

106 212

226

239

241

120135

150 200 250 300100

00

05

10

15

20

25

30

35

40

45

50

mz

Inte

nsity

times10minus6c

ps

(c)










1 212

（2 （（3 1a（2 （（3

2 226 （3（（（3

2a

N2b（2

（（3（3（

（3

（3

3 240 N （（3

（3

（3

NCH

3a（（3

（3

32

MBDMA

MDA 1

190∘C

120∘C

150∘C

160∘C

170∘C





MDA

1

02 h


MBDMA

32

60 h

20 h

05 h







Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974




3-TPD N

2



(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)




(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







1 212

（2 （（3 1a（2 （（3

2 226 （3（（（3

2a

N2b（2

（（3（3（

（3

（3

3 240 N （（3

（3

（3

NCH

3a（（3

（3

32

MBDMA

MDA 1

190∘C

120∘C

150∘C

160∘C

170∘C





MDA

1

02 h


MBDMA

32

60 h

20 h

05 h







Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974




3-TPD N

2



(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)




(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







Reactiontimeh

m(NaY)m(DMC)gg

n(DMC)n(MDA)molmol

MDAconversion

MBDMAYield

Selectivity

1 120 6 007 30 612 00 002 150 6 007 30 965 227 2353 160 6 007 30 100 392 3924 170 6 007 30 100 565 5655 180 6 007 30 100 911 9116 190 6 007 30 100 974 9747 200 6 007 30 100 975 9758 190 02 007 30 961 132 1379 190 05 007 30 100 266 26610 190 2 007 30 100 651 65111 190 4 007 30 100 942 94212 190 6 007 30 100 974 97413 190 7 007 30 100 974 97414 190 6 001 30 100 671 67115 190 6 003 30 100 962 96216 190 6 005 30 100 968 96817 190 6 007 30 100 974 97418 190 6 009 30 100 975 97519 190 6 007 15 100 876 87620 190 6 007 20 100 962 96221 190 6 007 25 100 965 96522 190 6 007 30 100 974 97423 190 6 007 35 100 974 974




3-TPD N

2



(c)

(b)

(a)

NaY

10 15 20 25 30 35 40 45 5052 theta (degree)




(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





(c)

(b)

(a)


0102030405060708090

100

Tran

smitt

ance

()


(c)

(b)

Inte

nsity

(a)

150 200 250 300 350 400 450 500 550 600 650100Temperature (∘C)








NaY catalysts


Pore volumecm3g

1 01 mdash 4082 0372 100 12 879 0163 103 13 540 015




3-TPD N






(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





(DMC)(MDA)

CO

O

DMCN N

(MBDMA)

Pathway (i)

(MDA)

C

(DMC)

DMCO

CO

O

N

DMC

Pathway (ii)

（2

（2

（2（2

（3

（3

（3

（3

（3

（3（（3

（（3

（3

（3O

（3

（3

（3

（2

（2

minus（3（

minus（3（

minus（3（

（3（

minus2

minus2

minus（3（

minus（3（

minus2

+

+

+

+

+

+

（（3

（（3（3（

（3（

（3（

（3

（3（（（3






4 Conclusion






Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls








Acknowledgments


References


































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls













Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




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