Characterization of Coal Tar Pitch and Paving Pitch by UV,EA and NMR

2011年3月化学工业与工程第28卷第2期CHEMICAL INDUSTRY AND ENGINEERINGVol 28文章编号:1004-9533(2011)02-0011-07Characterization of Coal Tar Pitch and PavingPitch by UV, EA and NMRXIAO Yan-hua, FENG Rui-jie, CAO Su-mei, LIU Xiang-yong, GAO Ting, PAN Zhi-quan(1. School of Chemical Engineering& Pharmacy, Wuhan Institute of Technology, Key Laboratory for Green Chemical Process of Ministry ofEducation, Hubei Key Laboratory of Novel Reactor Green Chemical Technology, Wuhan 430073, China; 2. Wuhan Pingmei WugangUnite Coking Chemical Corp LAd, Wuhan Iron Steel Group Co., Wuhan 430081, China)Abstract: In order to enlarge the use of coal tar pitch( CTP)in paving road, CTP and 60th paving pitch(PP)were extracted by n-heptane, toluene and ethanol step by step in a Soxhlet apparatus. The threeactions of CTP and PP were detected using UV-absorption UV-A), elemental analyses(EA) and nuclear magnetic resonance (NMR)firstly as a whole unit after quality characterization of physical nature ofCTP and PP were finished. The CTP had more saturate aliphatic and residue compounds dissolved in etha-nol. On the other hand there were more continental type structures of aromatic ring than that of PP. Therewas almost no residue in PP after extracted by ethanol. The results explained why CTP was crisp inwinter and was soften in summer The following research will focus on how to change the chemicalstruction of CTP into the relative similar structures with those of PP through adding polymer.Key words: coal tar pitch; paving pitch; quality characterization; elemental analyses; UV-absorption;中图分类号:TQ015.9;TQ028.3·1文献标志码:Areserves of petroleum and gas, whose life expectancy has way", transportation plays a very important role in thebeen estimated to be 40 and 60 years respectively.15 development of the Chinese economy. Now the demandillion tons of CTP, which is the main byproduct gener- to the quality and the quantity of Pp was increasing dayated in the coal carbonization process, are produced ev- and day in order to construct more and more highwayery year CTPs are the liquid products made from the For example in China, from"12th Five-Year"Plan to thecoal in the process of dry distillation and gasification, 2015, 35 thousand kilometers highway will be construc-and are complex combinations of rocyclic oxygen, poly- ted. Especially in this financial crisis, the Chinese gov-cyclic aromatic hydrocarbons(PAH's), nitrogen com- emment plans to invest much in construction of infra-pounds and sulphur24) CTP is an increasingly impor- structural facilities, among them including building free-tant commodity with high value such as binders for co- way 14. Now the mainly PP is the petroleum asphpolymers, electrodes for aluminum processing and steel enes. As presented above, it is very important to enlargemanufacture, super capacitors for fuel cells, and in the the application of CTP into PP as an alternative resourceproduction of carbon materials 4). In the world, demand to supply the insufficiency of petroleum asphalt.BeforeReceived date 2010-11-18中国煤化工Foundation item: Supported by the Progress Plan of Science Technnite Coking ChemicalCorp Ltd, Ltd of wISCo(2008Z012)CNMHGCorresponding author: XIAO Yan-hua, 1971, Female, Doctor, vice-professor, Maylor h l sTel:15337104642,Fax:86-027-87194648,E-mail:xiaoyh@mailwit.edu.cn.12化学工业与工程2011年3月using the CTP as PP, differences between them must be the solvents were methanol NMR spectra analyses wasclear so the methods can be chosen to change some recorded on a Bruker Advance 400 spectrometer withcharacterization of CtP to satisfy the need of PPTMS as internal standard the solvents were chloroformCTP has its advantages: good moist and adhesion, Elemental analyses were obtained on a Vario Microfighting against the erosion of oil, having an extremely cube( Elementar Co., Germany ) Needle penetrationhigh coefficient of friction. On the counterpart it has was tested on JNLY-97A( Wuxi Jinniu Equipment Co.some disadvantages, for example its thermal sensitivity Ltd). Ductility was detected on JNI005 A of extensome-is inferior so it is easy to be soft in summer and easy to ter( Wuxi Jinniu Equipment Co., Ltd ) Emulsificatioe brittle rupture in winter, easy to degrade, possess was obtained on a high shearing machine FT800( FLUpoor ductility. These weaknesses should be got over be- KO Equipment Shanghai Co., Ltd. ) All solvents werefore it would be used as PP. At all, freeway should be purchased with analytical reagent from Wuhan Lieranin a good condition in different seasons for a long time. TechnologySo the characterization of CTp was studied to discuss 1. 2 Pitch materialthe difference from that of Pp before it was applied inThe CtP was collected in November 2008 fromWuhan Pingmei Wugang Unite Coking Chemical CorpAt present, many researches were focused on the Ltd of Wuhan Iron Steel Group Corp (WISCO)omponents to identify the chemicals by standard ana-Hubei Province of China. The ctP whose medium tem-lytical techniques such as gas chromatography (GC), perature asphalt( softening point 65-90 C ), was col-size-exclusion chromatography( SEC ),matrix-assisteclected by engineer Su-mei Cao at Wuhan Pingmei Wrlaser desorption/ionization mass spectrometry( MALDI- gang Unite Coking Chemical Corp. Ltd. of WISCO. AMS)and other analytical methods. Though these re-voucher specimen( WG-37)was deposited at Wuhansearches, parts of the chemicals were known, but moreInstitute of Technology. WG-70 PP was supported bycomplex hydrocarbons have led to debate and to a levelEngineer Su-mei Caoof uncertainty in Refs. 10-20]. No single method is3 The physical nature of CTP and PPIn order to get the macroscopical physical proper-unambiguously capable of indicating molecular massties, several physical natures were detected through ditdistributions or chemical structural features in complexferent tools( shown in Table 1)fuel-derived mixtures it]. At the same time. the CtPTable 1 Properties of cTP and PPCTPPPmixtures, so the study on the integral nature occupies amore important position than chemicals'study in thisDensity/(gem))1.321.28respect. In this study, CTP and PP were identified as aSoftening point℃82.7whole through detection of their physical nature, UVNeedle penetration/(25 C, 1/10 mm)0absorption (UV-A), elemental analyses(EA) and nu-Ductility/(25℃,cm)0clear magnetic resonance( NMR) were used to explainPenetration Index0the diversities of characterization between CtP and PPUniform Uniformand fractionation allows the less abundant high massfractions to be observed more clearly. At this point, theIt was shown in Table 1 the properties of CTP andresearch is different from the other reportPP were very different. The density and appearance ofCTP were almost the same as that of PP. The higher1 Material and methods中国煤化工Way at relative low1.1 InstrumentsCNMH Glower needle pene-UV was obtained on a Lambda 35 spectrometer, tration and ductility of CTP than that of PP showed CTP第28卷第2期 XIAO Yan- hua et a. Characterization of Coal Tar Pitch and Paving Pitch by UV, EA and NMRwas hot short. The road surface was easy cracking and volved n-heptane, toluene and ethanol was carried outaveling when CTP was used in building freeway.step by step in a Soxhlet apparatus, different from the1. 4 Solvent fractionationseparation method reported in Ref. 21]. n-HeptaneThe pitches consist of the solid residue obtained toluene and ethanol were evaporated under reducedafter distillation of the tars from the pyrolysis of coal in pressure to give 3. 76 g( PHS-1), 3. 33 g( PTS-1)anda coke oven. The present sample was a medium tem- 0. 17 g (PES-1)residue, respectively. Portions of theperature" pitch, containing some light components (an- CTP were isolated as PHS-I, PTS-1 and PES-1(38%thracene oil fraction), such as phenanthrene, and has 33 %and 1. 7%, respectively, by weight). The ethanolbeen extensively investigated213. In this paper, the dissolvable residue occupied 27. 4%. With the samepitch was fractionated by solvent-solubility in Soxhlet method, WG-70 PP(PP)was separated byapparatus. Three fractions were produced: the pitch n- toluene and methanol in a Soxhlet apparatus continuheptane soluble( PHS )fraction, the pitch toluene solously. Correspondingly, the thiortions have 4. 62ble-heptane insoluble( PTs )fraction, and the pitch (PHS-2), 4.90 g( PTS-2), 0.48 g( PES-2), a furtherethanol soluble( PES)fraction, with each fraction ma11% was observed to be soluble in heptane; the heping up different percent of the whole. The characteriza- tane-insoluble fraction was 50.0% of the crude. Samtion of the asphaltenes was aided by separating eachples PHS-2, PTS-2, and PES-2 were 46. 2%, 49. 0%to three sub-fractions using Soxhlet extraction. These and 4.8%, respectively. No chemical was determinedfractions fell into three groups: lighter oil, low-and to be ethanol insolublehigh-aromaticity groups. The fractions of pitch materials 2. 2 Results of Uvfollow the method procedures described belowIt is known that the polyaromatic cores of theSample(10 g)HnsoLare rble for the absorbance in the uvRe.6后vis region. Clearly, the UV-absorption(UV-A)detectorReflux 6hwasnt sensitive to purely aliphatic material, althoughToluene sol.PP was known to contain material with a more aromaticcharacter than lighter fractions. UV-A detectors was op-Fig 1 Separation process of pitcherated at low sample concentrations to avoid self-absorption. The shift between CTP and PP was smallThe separation method of asphaltenes is described showing that the aromatic systems were similar in thein Figure 1. The medium temperature CTP in the CTP and PPprocess of dry distillation product pitch(10 g)was pul-There are some differences still between CTP fracverized and mixed with zeolite, enwrapped in non-wor. tions that we have used and PP fractions that we haveen fabrics, then extracted with n-heptane( 600 mL) for examined. The UV-vis( 230-450 nm)absorption6 h in Soxhlet apparatus, followed by changing round spectra of CTP and PP were shown in Table 2.Thebottom flask to one of same volume with toluene( 600 spectra of the two types of asphaltenes have been arbi-mL). The residue was extracted sequencely with tolu- trarily scaled to have similar absorbance in the long-ene and ethanol at the same condition. Then the solu- wave length region(i>450 nm). Such scaling alsotions were evaporated under reduced pressure to give leads to a crossing of the two spectra(i. e, a coincithree fractionsdence in absorbance )at 290 nm.2.3 H-NMR results2 Results and discussion中国煤化工parts of the same2.1 Weight and ratio of different solvent fractions tionCNMHG(3.33g,33%),lvent-solubility separation of the ctP(10 g)in- PES-1(0. 17 g, 1. 7%), PHS-2 (4. 62 g, 46%), PTS-2化学工业与工程2011年3月Table 2 Uv-A of several pitch samplesPHS.PTS.IPES-1PHS-2PTS-2288410358(4.90 g, 49%), PES-2(. 488, 4.8%)( Shown in PP were 28. 77% and 42. 28% for the PHS-2 andFigure 2). The portion of aromatic rings was found to PTS-2 fractions. It was clear the CTP sample was highsteadily increase in the following order: PHS PtS< er aliphatic and this result could be identified throughPES in CTP. It was detected that the ratios of aliphatic the aromatic proton values of 0, 9. 63%, and 29. 03%H to the whole area in CtP were 85. 32%.84 00%. were found for the PHs-1 Pts-1 and PES-1 fractionsand 65.68% for the PHS-1, PTS-1, and PES-1 frac- and 60. 79%(PHS-2)and 54. 625( PTS-2), respections respectively but aliphatic h to the whole area in tivelTable 3 Chemical shifts classifications and assignments of H-NMR of several pitch samples using CDCl, as the solventCTPPTS-1PES-IPHS-2PTS-2Chemical shiftArea ratio toArea ratio toArea ratio toArea ratio toefinitionwhole area/%whole area/%whole area/%whole arew/%0-2.0 Saturate aliphatic H 411.8684.0024.865.6813.7528.7731.8342.28aliphatic H in meth-yl or methylene rato to an aromatIc2. 2--3.0 which can be atta. 0.74 14.682.005.302.996.262.333.10ched in a y positionto another or theH in meth-3.5-4.52.004.184. 6-5.5 all other aliphatic H6. 5-9. 5 all aromatic H1.369.6310.9629.0329.0560.7941.1254.62Comparing the counterparts of CTP and PP in Ta- value of 4. 69 x 10 in PHS-2 showed there are doubleble 4, it was found that in PHS-l and PHS-2 the A of bond existed in aliphatic styles, in this point PP is veryaromatic H was 0 and 28. 1. From this result, it sugges. different from CTP.ted there were aromatic rings in the light part of PP, but 2.4 Elemental analysisin the CTP there was no aromatic ring or couldn't beThe results of EA for different parts of the samedetected because the amount was too small. As well as sample are listed in table 5. The atomic ratio of H/Cthe PTS-1 and PTS-2, it suggested that continental type was 1. 50, 1. 17, and 1. 04 for the PHS-1, RTS-l andstructures in PTS-2 were greater than those in PTS-1. It PES-l in CTP and was 0. 85 and 0. 63 in PP for PHS-2was found that for PHS-1 and PHS-2. the 'H NMR re. and中国煤化工 omic ratio of h/Cults suggested there were more portions of saturate ali- wasCNMHGe following order:phatic H in CTP than that of PP, and the experimental PHS > PTS PES whether in CTP or in PP. If we com第28卷第2期 XIAO Yan- hua et al.: Characterization of Coal Tar Pitch and Paving Pitch by UV, EA and NMRa)PHS-b)PTS-1NMR speTable 4 Calculation real proportion of H( H Ratio to whole area x percentage by weight x 100%)in several pitch samplesChemical shiftHydrogen definitionrange/x 10PHS-I PTS-1 PES-1 PHS-2 PTS-20-2.0Saturate aliphatic H32.427.71.113.3aliphatic H in methyl or methylene ratio to an aromat-2. 2-3.0 ic, which can be attached in a y position to another or 5.61.53. 5-4.5 aliphatic H in methylene ratio to two aromatic rings4. 6-5.5 all other aliphatic H6.5-9.5all26.8中国煤化工pared the counterparts of CTP and PP, it was found the derCN MHGPTS-2 The atomicatomic ratio of H/C was increased in the following or- ratio of H/c was the most important parameter in deci-16化学工业与工程2011年3月sion the aromatized situation in CtP or PP, Taken tosion was the same as theinterpretations from the detedgether, the Ea data imply that the aromatized structures tion results of H NMRin the PP is greater than that in the CTP. The concluTable 5 EA of asphaltene sub-fractionsCTPPPPitchPHS-1PTS-IPES-IPHS-2PTS-279.0679.2564.8565.2573.6573.7082.7382.4285.9085.8298479.9176.3306.4406.3876.4405.8285.8874.5354.510N0.451.671.000.920.934.1294.2052.3202.4465.7355.8350.6720.4850.4490.383atomic ratioH/C1.181,0411.0490.8450.8570.6340.N/C0.0050.0050.0210.0200.0110.0130.0090.0090.0120.011S/C0.0200.0200.0130.0140.0290.0300.0030.0020.0020.0023 Conclusiondrogen accepting modification of CTP, such as rubberplastic and resin, etc. From the consideration of envi-There are significant differences between the CTP ronmental protection, now our researchers pay much atfractions that we have used and PP that we have exam- tention to plastics known as white pollution)ined. First, the relative proportions of high-mass mate-rial in the PP samples were considerably smaller.TheReferencesethanol-insoluble fraction of the CTP was 27. 4%[ 1] SCHOBERT HH, SONG C Chemicals and materiawhereas the ethanol-insoluble fractions of the pp resifrom coals in the 21st century[ J]. Fuel, 2002, 81: 15dues was almost zero. Second the data showed aromaticlegree of PP was higher than that of CTP. These two[2] BLANCO C G, CANGA J S, DOMINGUEZ A, et al.Flame ionization detedresults seemed to contradict to each other. We considsome polycyclic aromatic compounds: Determination ofered in CtP chemical were existed in two extremethe main components of the coal tar pitch volatile fracways, either aliphatic chemicals or high polycondensedtion[J]. Journal of Chromatography, 1992, 607: 295arrangements, but in PP the situation was different. Themolecules in PP are highly aromatized than that of CTP [3] GUILLEN M D, IGLESIAS M J, DOMINGUEZ A, et alin smaller size on average. A large portion of saturatePolynuclear aromatic hydrocarbon retention indicesaliphatic in CTP but a relative large proportion of poly-SE-54 stationary phase of the volatile components of acyclic aromatic structures resulted that CTP is easy tocoal tar pitch: Relationships between chromatographic rebe crisp in cold winter and is easy to be soft in sum-tention and thermal reactivity[ J] Journal of Chromatogmer. The following research will focus on how to changeraphy,1992,591:287-295[ 4] NOEL L, AUTHIER-MARTIN M, PATRYthe chemical construction into the relative similar struc-Quantitative analysis of PAH in pitch by HPLC with flu-tures with PP in order that a large amount of CtP pro-omatic Compoundsduced annual could be used as PP, such as adding中国煤化工some light oil tar or polyer. Among the two solutions, [5]CNMH Ge of coal tar pitchthe latter attracted much attention because many poly-[J]. Coal chemical industry, 2000,94: 13-34s 28 t #2 M XIAO Yan-hua et al.: Characterization of Coal Tar Pitch and Paving Pitch by UV, EA and NMR[6] TURNER N R. Recent trends in binder pitches for re- [16] ACEVEDO S, GUTIERREZ L B, NEGRIN G, et al.Mo-duction anodes[ J]. Jom-Journal of the Minerals Metalslecular weight of petroleum asphaltenes: A comparisonMaterials Society, 1993, 45: 39-42between mass spectrometry and vapor pressure osmome-[7] WANG X. Who will benefit from the five trillion investtry[ J]. Energy Fuels, 2005, 19: 1 548-1 560ments on traffic and transportation[J]. Modem Enter. [17] BECKER C, QIAN K N,RUSSELL D H.Molecularprise Education, 2008, 11weight distributions of asphaltenes and deasphaltened[8] HOU X The things of reform and opening-up among 30oils studied by laser desorption ionization and ion mob-years[ J]. China Traffic Construction Engineering Con-ility mass spectrometry[ J]. Analytical Chemistry, 2008slants,2008,10:68-7180:8592-8597[9] DING W. Application and development tendency of tes- [18] MORGAN T J, GEORGE A, DAVIS D B, et al. Optimiza-ting technology to road[ J]. China Highway, 2007, 10tion of IH and 13C NMR methods for structural charac-terization of acetone and pyridine soluble/insoluble frac-[10] KARACA F, MORGAN T J, GEORGE A, et al. Molecu-tions of a coal tar pitch[ J]. Energy Fuels, 2008, 22:r mass ranges of coal tar pitch fractions by mass spec-1824-1trometry and size-exclusion chromatography [ J]. Rapid [19] SEKI H, KUMATA F. Structural change of petroleumCommunications in Mass Spectrometry, 2009, 23 2 087[11] MORGAN T J, GEORGE A, DAVIS D B, et al. On the [20] ISLAS C A, SUELVES 1, MILLAN M, et al. Matching avlimitations of UV-fluorescence spectroscopy in the detecerage masses of pitch fractions of narrow polydispersitytion of high-mass hydrocarbon molecules[ J]. Energyderived from matrix-assisted laser desorption ionisationtime-of-flight mass spectrometry with the polystyrene cal[12] HEROD AA, KANDIYOTI R, BARTLE K D Character-ibration of SEC[ J] Journal of Separation Science, 2003ization of heavy hydrocarbons by chromatographic and26:1422-1428mass spectrometric methods: An overview[J]. Energy& [21] HEROD A A, MILLAN M, MORGAN T J, et al.Positive-Fuel,2007,2l:2176-2203ion electrospray ionisation mass spectrometry of acetone-[13] BADRE S, GONCALVES C C, NORINACE K, et al. Mo-and acetonitrile-soluble fractions of coal-derived liquidlecular size and weight of asphaltene and asphaltene sol-Spectrometry, 2005, 11ubility fractions from coals, crude oils and bitumen[J]429442Fuel,2006,85:1-11[22]LazaRoiaNMJ,HeroDAA,KandiYotIR.com[14] MULLINS 0 C Rebuttal to comment by professors Her-parison of the fractionation of a coal tar pitch by solventsolubility and by planar chromatography[ J]. Fuel, 1999asphaltene solubility fractions frocoals,crude oils and bitumen[J]. Fuel, 2007, 86: 309[23] HEROD A A, LAZARO M J, SUELVES 1, et al. Size ex-[15] TANAKA R, SATO S, TAKANOHASHI T, et al. Analysisclusion chromatography of soots and coal-derived materi-of the molecular weight distribution of petroleum asphaltals with 1-methyl-2-pyrrolidinone as eluent: Observationsenes using laser desorption-mass spectrometry[J].Ener-on high molecular mass material[ J]. Energy Fuelsgy&Fues,2004,18:1405-1413000,14:1009-1020中国煤化工CNMHG