分子模拟与理论计算在多相催化研究中的应用课件.ppt

1、分子模拟与理论计算在多相催化研究中的应用分子模拟与理论计算在多相催化研究中的应用王建国王建国 焦海军焦海军 李永旺李永旺 中科院山西煤化所中科院山西煤化所计算化学虚拟实验室全体会议，北京，2004-10-21研究背景研究背景化学工业催化过程多相催化化学工业催化过程多相催化转化率高、选择性好、可稳定运行转化率高、选择性好、可稳定运行催化剂相适应的工艺催化剂相适应的工艺实验理论研究实验理论研究煤化所已开展的计算模拟工作煤化所已开展的计算模拟工作研究内容研究方法煤的结构与反应性催化剂制备与活化催化剂结构与活性位表面吸附扩散与反应相平衡 化学平衡催化反应动力学浆态床反应器设计反应器流场模拟量子力学分子

2、力学量子力学量子力学、分子力学化学热力学、分子力学机理动力学、模型化动力学模型、流体力学流体力学、统计物理骨干成员骨干成员王建国百人计划分子筛、反应工程李永旺百人计划过渡金属、反应动力学焦海军百人计划煤、催化剂、量化计算孙予罕百人计划催化剂设计、分子模拟郭向云百人计划催化材料、分子模拟毕继诚百人计划反应器、流场模拟秦张峰德国马普流体热力学、分子模拟王逸凝博 士催化反应动力学计算袁淑萍博 士分子筛，量化计算董 梅博 士分子筛，模拟计算霍春芳博 士过渡金属，量化计算杨晓峰理论物理硕士，博士生超临界流体分子模拟郭庆杰石油大学、德国洪堡反应器、流场模拟张 凯洪若瑜石油大学、剑桥博士后苏州大学、美加博士

3、后流体力学、分子模拟流体力学、流场模拟主要成员及合作者主要成员及合作者催化剂反应性能催化剂制备与改性孔结构与表面性质吸附扩散反应性大量文献工作实验测定分子模拟实验关联分子模拟量化计算分子筛催化剂的设计分子筛催化剂的设计结构规整孔道均匀特殊的形状选择性活性位简单明确构形扩散无理论模型分子筛结构、表面酸性与形状选择性分子筛结构、表面酸性与形状选择性分子力学方法在分子筛研究中的应用q吸附吸附热吸附平衡常数吸附等温线吸附位q扩散（MD/MC）路径、机理（构形扩散？）扩散系数与孔道结构关系q形状选择反应q模扳剂的选择与作用024681012P,kPa04812Molelules per unit cel

4、lbenzene in silicalite at 293Kthis work:simu.Wu et al.:exp.Guo et al.:exp.1234455687Reactant in gaseous phaseReactant in sorbed phaseProduct in gaseous phaseProduct in sorbed phase1234455687Reactant in gaseous phaseReactant in sorbed phaseProduct in gaseous phaseProduct in sorbed phaseMonte Carlo mo

5、del:1.collision with frequency(mols/step)2.adsorption of reactant3.desorption of reactant4.diffusion of reactant5.diffussion of product6.desorption of product7.adsorption of products8.exit of product分子筛吸附扩散反应的分子筛吸附扩散反应的Monte Carlo模拟模拟建立了形状选择性与建立了形状选择性与K、D、k的关系的关系Wang et al.,Zeolites,1995,15:288;Cata

6、l.Lett.,1995,54:65;1994,24:395;26:189;Stud.Surf.Sci.Cata.,1994,88:525.ZSM-5分子筛中的烷基化/歧化反应transition stateshape selectivityDoDmDp+RR2RRRRR+RXRR+HXRR RRX+RRproductshape selectivityKlemm,Wang,et al.,Chem.Eng.Sci.,1997,52:3173-3182.ZSM-5中乙苯烷基化/歧化反应0.010.101.0010.00100.00Thiele modulus0.000.200.400.600.80

7、1.00Spprim.distr.0/0/10010/10/8010/20/7010/30/6010/40/5010/50/407/63/30Productshape selectivityTransition stateshape selectivityExperimental resultsDkRRTEaAek/RTEDeDD/0DaEE T Monte Carlo simulationsq吸附吸附热吸附平衡常数（K）吸附等温线吸附位置q扩散路径及与孔道关系0204060801000.00.20.40.60.81.0399 K381 K361 K342 K323 K Capacity(mm

8、ol/g)Pressure(mbars)Adsorption,2004,in press.J.Mol.Struct.,2004,679:95;Micropor.Mesopor.Mater.,2001,43:237Colloids&Surfaces,2004,in press.benzene in CoAlPO4-5吸附扩散反应性与孔道结构、表面性质的关联吸附扩散反应性与孔道结构、表面性质的关联分子模拟与实验1.52.02.53.03.5-4048 lnK103/T(K-1)benzene cyclohexane hexane分子筛中吸附的隔离效应分子筛中吸附的隔离效应Nature of the

9、 traffic control shape selectivity?aromaticsn-paraffinsCF4CH4骨架结构与催化中心位置表面酸强度与分布物理吸附or化学吸附扩散机理与活化能（D）反应路径与过渡态（k）J.Mol.Catal.A,2004,in press;2002,178,267;2001,175,131;J.Phys.Chem.A,2002,35,8167;J.Mol.Strcut.,2004,674,267吸附扩散反应性与孔道结构、表面性质的关联吸附扩散反应性与孔道结构、表面性质的关联量子化学计算量子化学计算ED分子筛的结构取代位置及平衡质子在取代位置及平衡质子在M

10、OR中的位置中的位置MM位置H位置BT4O2/10AlT4O10GaT4O10FeT2,T4O2/3/5,O2/10ZnT4O2+O10虽然所研究的杂原子均可占据虽然所研究的杂原子均可占据T3位，但由于其位于小位，但由于其位于小孔内，在催化反应中并不重要孔内，在催化反应中并不重要T2O7O9O8O6O1O2,5O3O4T4T3abO10T1MZSM-5MORAl337.9320.0Ga339.5321.6Fe344.5325.4B357.3341.6分子筛的酸性M-ZSM-5和和MOR的质子亲合势的质子亲合势(kcal/mol)H2O,NH3在B,Al,Ga,Fe-MOR中的吸附MZSM-5M

11、ORAl+Ga+Fe-+B-研究表明，H2O的吸附均为物理吸附，而NH3则随杂原子而不同-+质子化；-物理吸附分子筛的吸附性能量子力学和分子力学组合方法q基本思想：把整个体系分割成三个区域q兼具量子力学的精确性和分子力学的高效性 MMQM+MMQMSiOzAlO1O2HzNH2H1OzAlO2O3O5O4HzNH1H3H2SiO1O5SiOzAlO3H5H2H3O1O2H4NO4H1HzO4OzAlO1O5O3HzH2H3H4SiNH1O2Amines adsorption in HMORNH3Me2NHMeNH2Me3Nn吸附过程中发生了酸性质子从沸石到胺分子的转移吸附过程中发生了酸性质子从

12、沸石到胺分子的转移n质子化的胺离子与沸石之间存在着多重氢键作用质子化的胺离子与沸石之间存在着多重氢键作用J.Mol.Catal.,2004,220:221-228.Adsorption energies(kJ/mol),proton affinities(PA;kJ/mol),and the corresponding pKa of the conjugate acid of amines qWhen measured by their adsorption energies on acidic zeolites,the basicity of these amines increases a

13、s follows:NH3 MeNH2 Me3N Me2NH,which agrees well with the experiments,but differs from those in the gas phase(PA)and in solution(pKa).J.Mol.Catal.,2004,submitted.Pyridine 在ZSM-5中的吸附Pyridine大小与大小与ZSM-5的的intersection相近，以下相互作用相近，以下相互作用同时，小同时，小cluster模型不能得到合理结果。模型不能得到合理结果。qN与质子酸中心间氢键作用与质子酸中心间氢键作用qN:与电荷平

14、衡离子间作用与电荷平衡离子间作用qPyridine中中H与骨架与骨架O间作用间作用qPyridine芳环与电荷平衡离子间作用芳环与电荷平衡离子间作用channel intersectionAlstraight channelAlsinusoidal channelAlZSM-5 的两类孔道及其交叉位的两类孔道及其交叉位吡啶在吡啶在ZSM-5分子筛中的吸附热分子筛中的吸附热Ed,kJ/mol分子筛分子筛实验值实验值计算值计算值平衡离子平衡离子骨架氢键骨架氢键H-ZSM-5200519758%42%Li-ZSM-5155-19517360%40%Na-ZSM-512012268%32%aromat

15、icsn-paraffinsJ.Phys.Chem.,2004,submitted.RCH=CH2 +CO +H2 RCH2CH2CHORCH2CH2CHOor R(CH3)CHCHOHCo(CO)4(RCH2CH2)(CO)Co(CO)3(H)2or(RCH3CH)(CO)Co(CO)3(H)2HCo(CO)3(RCH2CH2)(CO)Co(CO)3or(RCH3CH)(CO)Co(CO)3CH2=CHRHCo(CO)3(CH2=CHR)Co(CO)4(CH2CH2R)orCo(CO)4(CHCH3R)Co(CO)3(CH2CH2R)orCo(CO)3(CHCH3R)CO-CO+COH2(i

16、)catalyst generation(ii)olefin coordination(iii)olefin insertion(iv)CO coordination(v)CO insertionor carbonylation(vi)H2 oxidative addition(vii)aldehyde reductive elimination with catalyst regeneration(vi)H2 coordinationOrganometallics 2003,23,4665-4677.HCo(CO)3 catalyzed hydroformylation of propene

17、HCo(CO)3 catalyzed hydroformylation of acetyleneOrganometallic 2004,23,765-773.CoOCOCCOCH2CH2CHOCoOCOCCOCH(CHCH2)OHCoOCOCCOOCH2CHCH2HHCoOCOCCOCH(CH3)CHOHHHHHHCoOCOCCOHOCoOCOCCOHCHOCoOCOCCOCH(CHCH2)OHCoOCOCCOCH2CH2CHOCoOCOCCOCH(CH3)CHOCoOCOCCOHOCoOCOCCOOCH2CHCH2CoOCOCCOHOCHCHCH2OCCoOCHHCH(CHCH2)OHCOO

18、CCoOCHHOCH2CHCH2COOCCoOCHHCH2CH2CHOCOOCCoOCHHCH(CH3)CHOCOH2C(OH)CHCH2CoOCOCCOHH2C(CH3)CHOCoOCOCCOHHOCH2CHCH2CoOCOCCOHH3CCH2CHOCoOCOCCOH+H2+H2Path APath BPath CPath D+H2+H2The proposed reaction pathways for the hydrogenation of acrolein Organometallic 2004,23,2168-2178.Adsorptions of metal cluster on

19、 regular and defect sites of the MgO(001)surface The formation of the vacancies on the MgO(001)surfaces J.Phys.Chem.B 2004,108,8359-8363.CO Adsorption on Fe5C2(001)(a)(b)(c)J.Phys.Chem.B 2004,108,9094-9104.CO Adsorption on the(001),(110)and(100)surface of Fe5C2J.Phys.Chem.B 2004,108,9094-9104.Hydrof

20、ormylation and isomerization of allene and propyneCCHH3CCCH2H2CCat.HCo(CO)3CoOCOCCOCCoOCOCCOCHHCCoH2COCCOCH2COCHCat.HCo(CO)3CO/H2CHOH2CCO/H2OHCH3CCH2CO/H2H3CCHOControlling factor of regioselectivityG=16.3 kcal/molG=0.7 kcal/molno regioselectivityChem.Eur.J 2004,in press.Work in progress of publicati

21、on(1)Thiophene HDSWork in progress of publication(1)Thiophene will be first hydrogenated into 2,5-dihydrothiophene,from which Butadiene will be eliminated directly via a intramolecular way.Therefore,butadiene is the ONLY logical HSD product.Tetrahydrothiophene will be first dehydrogenated into 2,5-d

22、ihydrothiophene,and then go to butadiene,as found experimentallyWork in progress of publication(2)CO adsorption on the Fe(111)surfaceWork in progress of publication(3)At 1/3 and 1/2 ML coverage,the shallow-hollow adsorption is the most stable site,while both shallow-hollow and bridge adsorption can

23、coexist at 1 ML.Energetically,the bridge site rather than the suggested deep-hollow represents the reasonable adsorption configuration.In contrast,bent CO on-top and triply capping adsorption are the most favored forms at 2 ML.CO adsorption on the MoS2 surfaceWork in progress of publication(4)The ad

24、sorption energy of high coverage shows the additivity as compared with that of one CO ad-sorption,and there is no significant repulsive interaction between the end-on adsorbed CO probes.No bridged CO ad-sorption is favored energetically and this might explain the catalytic ability of MoS2 for C1 products instead of higher hydrocarbons and alcohols.甲醇乙醇丙醇丁醇致 谢中国科学院国家科技部山西煤化所国家自然科学基金委德国洪堡基金会