Studies on Ion-molecule Reaction of Disubstituted Benzene with IonSystem of Acetyl Chloride in Gas P

Vol. 16No. 42000Chemical Research in Chinese Universities334~340Studies on Ion-mol ecule Reaction ofDisubstituted Benzene with IonSystem of Acetyl Chl oride in Gas PhaseLI Zhi-li(Shandong Nom- metallic Material Research Institute, Jinan 250031, P. R. China)(Recived Dec. 19, 199)The ion-molecule reactions of disubstituted benzenes with the ion system of acetyl chlorideunder the chemical ionization condition were examined and the fragmentation reactions of theadduct ions formed by the ion- molecule reactions were studied by using ollision-induced dissocia-tion technique. It was found that the electron-releasing groups favored the adduct reactions andthe electron- withdrawing groups did not. The position and properties of substituting groups hadan effect on the relative abundance of the adduct ions. The fragmentation reaction of the adductions formed by ortho-benzene diamine with the acetyl ion was similar to the reductive alkylationreaction of amine in condensed phase.Keywords Disubstituted benzene, Ion -molecule reaction, Collision-induced dissociation tech-nique, Adduct ionArticle ID 1005-9040(2000)-04-334-07IntroductionThe intramolecular function group interaction plays an important role in gas-phase ion-molecular reactions and the fragmentation reactions of its product ions0-12]. The fragmenta-tion reactions of the odd electron ions of benzoic acid[13]， phenylacetylene[14], phenylsul-fide[1s], nitrobenzene[16]， methoxybenzaldehydel1] and acetophenoneL8] obviously show theortho effect. The fragmentation properties of the protonated molecules and the adduct ions ofo,m,p-methoxy- acetophenone, o,m, p-hydroxyacetophenone , o,m,p methoxy-benzaldehydeand o,m, p-hydroxybenzaldehyde were reported[l9,20], The ortho effect of even -electron ionsof other disubstituted benzenes occurred under the collision-induced dissociation(CID) condi-tion, and the properties of the function groups had an effect on the fragmentation pathways ofthe adduct ions[2),22].In the present work, we studied the ion molecular reactions of a series of disubstitutedbenzenes with acetyl chloride and the CID reaction properties of their adduct products.Experimenta'中国煤化工All the experiments were performed by using a thYHC N M H Gspectrometer(Finnigan MAT TSQ-70B). The CID spectra were measured by using the first quadrupole toNo. 4LI Zhi-li335select the precursor ions according to their mass，which were focused into an r. f. -onlyquadrupole collision cell containing research- grade helium collision gas maintained at an esti-mated pressure of 2. 67X10-3 Pa, which was low enough to ensure single-collision conditionsessentially. The CID ionic fragments and the survived precursor ions were monitored by scan-ning the second quadrupole analyzer over the desired mass range. The acetyl chloride was in-troduced into the ion source through the GC/MS interface. The flow-rate was controlled bythe gas sampling valve to maintain the stable ion current inside the ion source. The sampleswere introduced into the ion source by the inlet probe. In terms of melting point of the sam-ples, the different probe temperatures were set up to obtain the stable ion current.All the samples were commercial available.Results and Discussion1 The Adduct Reaction of Disubstituted Benzenes with the lon System of Acety| ChlorideThe major adduct ions formed by the ion-molecule reactions of 11 groups of disubstitutedbenzenes with the ion system of acetyl chloride and the corresponding relative abundances arelisted in Table 1.Table 1 Major adduct ions formed by 11 groups of disubstituted benzenes with the ionsystem of acetyl chloride and the corresponding relative abundances'CompoundMajor ions(m/z) and their relative abundance(%)_M+ [M+H]+ [M+ 43]+ [MH+ 60]+[MH+78]+ [M+ 103]+ [2M+H]+ [2M+43]+1.2-Phenylenediamine 108(60) 109(95) 151 (100)187(19)211(27)217(63)259(60)1,3-Phenylenediamine 108(5)109(100) 151(30)187(10)211(10)217(45) 259(16)1.4-Phenylenediamine 108(24)109(100) 151(39)187(24)211(50)217(40)59(7)1,2-Aminopbenol109(65)110(100) 152(55)170(3)188(4)212(73)219(18)261(8)1,3-Aminophenol109(70) 110(100) 152(32)170(2)188(2)212(68)219(17)261<6)1,4-Aminophenol109(90)110(100) 152(30)170(5)188(5)212(71)219(20)261(5)1,2-Nitroniline138(65) 139(90) 181(100) 199(2)217(3)241(18)277(54) 319(5)1,3-Nitroeniline138(9)139(100) 181(73)199(7)217(5)241(26)277(20)1.4-Nitroaniline138(8)139(100) 181(70)199(2)217(2)241(29)277(48)1,2-Chloroaniline127(100) 128(95)188(3)206(20)230(82)255(98) 297(3)1,3-Chloroaniline127(100) 128(96) 170(3)206(14)230(76)255(50)297(14)1,4-Chloroaniline127(94) 128(100) 170(22)188(6)206(31)230(66)255(43) 297<2)1,2-Toluidine107(100) 108(94)186(5)210(36)215(100) 257(4)1,3-Toluidine107(94) 108(93) 150(8)168(4)186(10)210(20)215(95) 257(60)1 ,4-Toluidine107(90) 108(100) 150(22)168(10) 186(16)210(18)215(100) 257(98)1,2 Dihydroxybenzent 110(90) 11(100) 153(60)221(20) 263(14)1,3-Dihydroxybenzene 110(82) 11(84) 153(100)221(10)263(10)1,4-Dihydroxybenzene 110(95) 11(84) 153(100)213(3)221(8)263(21)1.2-Cresol108(20)109(18) 151(100)259(5)1,3-Cresol108(100) 109(90) 151(88)259(10)1,4-Cresol108(100) 109(100) 151(82)259(8)1,2-Nitrophenol139(90) 140(54) 182(100) 200(4) .242(18)279(2)321(8)1, 3-Nitrophenol139(60) 140(81) 182(90)200(2)中国煤化工1.4-Nitrophenol139(24) 140(100) 182(95)200(3)1 ,2-Choronitrobenzene 157(81) 158(16) 200(100) 218<22)MYHCNM H G_357(4)Continued to next page.336Chemical Research in Chinese UniversitiesVol. 16CompoundMajor ions(m/z) and their relative abundance(%)_M+__ [M+H]+ [M+43]+ [MH+60]*[MH+78]+ [M+103]+ [2M+H]+ [2M+43]+1 ,3-Chloronitrobenzene 157(86) 158(30) 200(40) 218(10)315(10)1,4- Chloronitrobenzene 157(100) 158(75) 200(20)218(5)315(9)1.2-Bromonitrobenzene 201(90)202(10) 244(100)1,3-Bromonitrobenzene 201(19) 202(3) 244(100) 262(6)1 ,4-Bromonitrobenzene 201(81)202(7)244(100) 262(4)1,2-1odonitrobenzene 249(90) 250(14) 292(100) 310(8)1 ,3-lodonitrobenzene249(100) 250(16) 292(65) 310(5)1,4-lodonitrobencene249(100) 250(20) 292(46)_ 310(6)# 43, 60, 78 and 103 in the square brackets represent CH,CO, HCO,H, ecetyl choride and (CH2CO+CHzCO2H),respectively.Based on the data in Table 1, the major adduct ions were [M+H]+, [M+CH2CO]+,[M +CHsCO+CHzCO2H]+ , [2M+CHzCO]+ and protonated molecular dimers. With thechange of function group properties from electron-releasing to electron-withdrawing groups,such as from amino, hydroxy to nitro group, the number of the adduct ions and the corre-sponding relative abundances changed. The data in Table 1 shows that the differences are re-lated to the position and the properties of the function groups, and the electron-releasinggroups favored to the adduct reaction,2 CID Reactions of the Adduct lons [M+CHzCO]+ of Disubstituted Benzene isomersThe CID reaction results of the adduct ions [M +CHzCO]+ of the disubstituted benzenesare listed in Table 2.Table 2 CID reaction results of the adduct ions [M+CH,CO]+ of the disubstituted benzenesPrecursor ions(m/z)Product ion(m/z)[M+CH:CO]+[M+H]+[CHzCO]+ [M+C:H]t[M-H0]+1 ,2-Phenylenediamine1511 09431331 ,3-Phenylenedisnine51109 .1,4-Phenylenediamine10931 ,2-Aminophenol152110 .1,3-Aminophenol52110131,4-Aminophenol1.2-Nitroaniline81139t31,3-Nitroaniline1,4-Nitroaniline1811,3- Chloroaniline701281,4-Chloroaniline1701,3-Toluidine50108l31,4-Toluidine150101 ,2-Dihydroxybenzene531111,3-Dihydroxybenzene153111,4-Dihydroxybentene$31,2-Cresol1,3-Cresol1,4-Cresol中国煤化工1,2-Nitrophenol1821401221 ,3-Nitrophenol82_140CNMH GContinued to next page.No.4LI Zhi-liCompoundPrecursor ions(m/z)Product ion(m/z)[M+CH,CO]+[M+H]+[CH,CO]+ [M+C2H]+[M-HO]+1.4-Nitrophenol1821404:1, 2-Chloronitrobenzene200481,3-Chloronitrobenzene1 ,4-Chloronitrobenzene20.4:1 ,2-Bromonitrobenzene2441.3- Bromonitrobenzene1.4-Bromonitrobenzene1.2-Iodonitrbensene2941.3-odonitrobenzene2921,4-lodonitrobenzeneAccording to the data in Table 2, it can be found that the common fragmentation path-way for the adduct ion [M +CHgCO]+ was to produce the protonated molecule and the acetylion. During the dissociation process, one fragmentation pathway is that H+ was transferredfrom the acetyl ion to the neutral molecule, the other is to generate the acetyl ion. The resultssuggest that the fragmentation reactions of the adduct ions underwent an intermediate ion-neutral complex. The proposed fragmentation reaction mechanism of [M+CH3CO]+ isshown in Scheme 1.XNH,NHzCID^NHCH,.CO*!+[M+H]**|oHordec=CH,J L - cH,co+m/x 43“NH;Scheme 1 Proposed fragments tion mechanism of the adduct ion[M+CHzCO]+ of the disubstituted benzenes.The different dissociation route of the o-phenylenediamine adduct ion is that the ion[M+CH,CO]+ could produce the fragment ion m/z 133 and lose 18 amu neutral species.NHi~Ht_NHN gc ChH, CH,CO+CHiC-oH.m/x 151m/t 151-H20| CIDNH, ;+ ./N -C=CH,CH,=C=NH +回中国煤化工m/r 92HCNMHGScheme 2 Proposed fragmentation mechansm or the adduct ion[M+CHzCO]+ of o phenylenediamine.338Chemical Research in Chinese UniversitiesVol. 16The product ion m/z 133 further fragmented to generate the ion m/z 92 and lost 41 amu neu-tral species. The proposed fragmentation mechanism of the ion [M +CH:CO]+ is shown inScheme 2. This reaction is similar to the reductive alkylation reaction of amine in the con-densed phase.The different fragmentation routes of the o-nitrophenol adduct ion are that the ion[M +CHzCO]+ (m/z 192) could dissociate to generate the product ion m/x 122 and lose 60amu neutral species. The proposed fragmentation mechanism is shown in Scheme 3.0+ H0OCOCH,>0m/z 182m/z 122Scheme 3 Proposed fragmentation mechanism of the adduct ion [M+CH,CO]+ of o-nitroaniline.3 CID Reaction of the Adduct lon [M+CHzCO+CHzCO;H]+The CID reaction results of the adduct ions [M +CH;CO+CH:CO2H]+ of the disubsti-tuted benzenes are listed in Table 3.Table 3 CID reaction results of the adduct ion [M+CHsCO+CHzCO2H]+ of the disubstituted benzenesCompoundsPrecursor ions(m/z)Product ions(m1z)[M+CH20O+CHCO,H]+[M+H]+[CH,CO]+ [M+CHzCO-H:O]+1 ,2-Phenylenediarmine2111094:1331, 3-Phenylenediamine091,4-Phenylenediamine431 ,2-Aminophenol212101,3-Aminophenol1,4-Aminophenol121,2-Nitroaniline241391.3-Nitraniline1,4-Niroaniline1,2-Chloroaniline2301281.3-Chloroaniline1.4-Chloroaniline281.2-Toluidine210081.3-Toluidine1.4-Toluidine1.2-Nitrophenol242401.3-Nitrophenol1.4-Nitrophenol1404The data in Table 3 suggests that the main product ions produced by the CID reaction ofthe adduct ions [M +CHsCO+CHzCO2H]+ of the disubstituted benzenes were the protonatedmolecule, indicating that it was a proton-bonded mc中国煤化工e fragmenta-tion process , the proton was transferred from acetylYHCNMHG4 CID Reaction of the Adduct lon [2M+CHzCO]+The CID reaction results of the ions [2M+CHsCO]+ are listed in Table 4.No. 4LI Zhi-i339Table 4 CID reaction results of the adduct ions [2M +CH,CO]+ of the disubstituted benzenesCompoundsPrecursor ions(m/z)Product ions(m/z)[2M+CH,CO]+[M+CH,CO]+[M+H]+[2M+H]+1. 2-Phenylenediamine251091,3-Phenylenediamine2591511,4-Phenylenediarmine091 ,2-Aminophenol2611521101,3-Aminophenol101,4-Aminophenol1,2-Nitroaniline319181391,2-Chloroaniline1701281.3-Chloroaniline297，1,4-Chloroaniline297281,2-Toluidine2571501081.3-Toluidine081,4-Toluidine1.2-Dihydroxybenzene63153111 ,3-Dihydroxybenzene1.4-Dihydroxybenzene2631,2-Cresol2171,3-Cresol1,4-Cresol1,2-Nitrophenol211821401.2-Chloronitrobenzene357200158Based on the data in Table 4, we infer that the fragmentation reaction of the ion [2M+CHgCO]+ from the cresol isomer was different from that of the others. The product ion ofthe former was [2M+ H]+, and those of the ltter were [M + CHzCO] and [M + H]+.These results indicate that they had different structures, and suggest that the structure of theion [2M + CH]CO]+ , which fragmented to generate [M +CHsCO]+ and [M +H]+, hadtwo kinds of combined manner between reactants, with the aid of hydrogen bond and proton-bond. The proposed fragmentation mechanism is shown in Scheme 4. The ion [2M十CHsCO]+, which dissociated to give [2M +H]+，formed a proton-bonded molecule dimer.. Chio向- NH,cACHm/z 257NH;H+ 牛+ CH2CO[CH,CH,HN-_-.-H_NH合|. CIDm/x 108NH,--Ht- 0CCH21NH中国煤化工m/x 257CNMHGScheme 4 Proposed fragmentation mechanism of the adduct ion [2M+ CHzCO]+ of toluidine isomer.340Chemical Research in Chinese UniversitiesVol. 16The proposed fragmentation mechanism is shown in Scheme 5.HOQHHO-" !~QHCH,CO+HcAm/r 259m/x 259CIDHO --Ht_LHCH0| 0”CHm/x 217Scheme 5 Proposed fragmentation mechanism of the adduct ion [2M+CHzCO]+ of cresol isomer.References[1] Aue, D., Web, H. and Bowers, M., J. Am. Chem. Soc. , 95, 2 699(1973)[2] Meot-Ner, M., J. Am. Chem. Soc., 105, 4906(1983)[3] Didic, I. and McClocskey, J,J. Am. Chem. Soc. , 93, 4 955(1971)[4] Weinkam, R. and Gat, J., Org. Mass Spcetrom., 11, 188(1976)[5] Ashkenazi, P., Blum, w., Domon, B. etal.，J. Am. Chem. Soc., 109, 7 325(1987)[6] Meot-Ner, M.，J. Am. Chem. Soc., 105, 4 912(1983)[7]Morton, T. and Beauchamp,J.,J. Am. Chem. Soc., 94, 3 671(1972)[8] Mueller, D., Domon, B., Blum, w. et al. ,Org. Mass Spectrom.，24, 157(1989)[9]Ramana, D. , Sundarom, N. and Gtorge, M. , Org. Mass Spetrom. , 25, 161(1990)[10] Vainiotalo, P. and Malkonen, P. , Org. Mass Spectrom. , 22, 493(1987)[11] Harrsion, A. and Kllury, R. , Org. Mass Spectrom., 15, 277(1980)[12] Kingston, E. , Shannon, J. and Lcey, M., Org. Mass Spectrom., 18, 183(1983)[13] Riley,J, Baer, T. and Marbury, G.,J. Am. Soc. Mass Spectrom. , 2, 69(1990)[14] Ramana, D. and Ramakrishna. , Org. Mass Spectrom. , 24, 317(1989)[15] Ramana, D. , Sundaram. N. and George, M.，Org. Mass Spectrom. , 23, 63(1988)[16] Bursey, ]. T, Bursey, M. M. and Kingston, D. G. 1, Chem. Rev., 73, 191(1973)[17] Filges, U. and Gritzmacher, H. F., Org. Mass Spectrom. 21, 673(1986)[18] Filges, U. and Grutzmnacher, H. F., Org. Mass Spectrom. , 22, 44(1987)[19] Donovan, T.. Liou,J. and Brodbelt, J,J. Am. Soc. Mass Spectrom. , 3, 47(1992)[20] Donovan, T. and Brodbelt, J., Org. Mass Spectrom.，27, 9(1992)[21] Olear,J. L, Wright,L. G., Cooks, R. G. e al., Org Mass Spectron.，22, 348(1987)[22] Zhili, L. , Shuying, L. and Fengrui, S.，Rapid Comun. Mass Spectrom. , 12, 105(1998)中国煤化工MHCNMHG