New第八章-计算机分子模拟应用实例ppt课件.ppt

,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,二级,三级,四级,五级,*,计 算 机 分子模拟,计算机分子模拟应用,-,咪唑啉类缓蚀剂缓蚀机理的研究,研究背景,研究方法,研究对象,研究内容,结 论,码头上浮船及锚链的腐蚀,3,水中打捞的摩托车的锈蚀状况,4,齿轮片的腐蚀表面,5,铜器表面生成一层薄薄的铜绿,铜绿的主要成分是,Cu,2,(OH),2,CO,3,酸雨腐蚀的文物雕像表面,8,四川省宜宾市城区的南门大桥,钢铁,生锈,造成大桥,断裂,！,铁锈斑斑,某居民楼水管腐蚀状况,11,管道内壁腐蚀,12,下水道局部腐蚀状况,13,管道外壁局部腐蚀状况,14,研究背景,腐蚀是困扰油气工业发展的一个极为突出的问题。,添加缓蚀剂是一种有效的防腐手段。,新型缓蚀剂的设计开发迫切需要理论指导。,缓蚀机理的实验研究工作的局限性。,分子模拟技术为深入研究缓蚀机理创造了条件。,研究对象,CO,2,腐蚀是石油工业中一种常见的腐蚀类型,CO,2,是油气伴生气,注,CO,2,强化开采工艺,咪唑啉类缓蚀剂,研究对象,研究方法,量子化学计算,分子力学,分子动力学模拟,开展缓蚀机理的,多尺度模拟研究,以期通过系统的理论研究，丰富和完善缓蚀剂作用理论，并为新型有机缓蚀剂的设计与开发提供理论指导。,咪唑啉类缓蚀剂,研究内容,1,咪唑啉分子反应活性的密度泛函理论研究,2,咪唑啉缓蚀剂自组装膜的成膜机理研究3,液相条件下咪唑啉在金属表面吸附的,MD,研究,4,腐蚀介质在缓蚀剂膜中扩散行为的,MD,研究,1,咪唑啉分子反应活性的密度泛函理论研究,研究目标：,1,、明确咪唑啉分子的活性区域和活性位点分布；,2,、分析烷基链长对分子反应活性的影响。,反应活性,全局反应活性,局部反应活性,全,局,反,应,活,性,化学势,(,),总能量（,E,）、电子数（,N,）,软度,(,S,),硬度,(,),体系总能量,E,对,N,的一阶导数,体系总能量,E,对,N,的二阶导数,亲电指数,(,),衡量一个分子的亲电子能力大小,分子的硬度越小，软度越大、化学势的绝对值越大、亲电指数越大，表明分子的反应活性越强、越容易得到（失去）电子。,表,2 AH,缓蚀剂分子的,化学势,(,),、,硬度,(,),、,软度,(,S,),和亲电指数,(,),Molecule,/eV,/eV,S,/eV,-1,/eV,A,-1.81,3.26,0.31,0.50,B,-1.85,3.26,0.31,0.52,C,-1.82,3.26,0.31,0.51,D,-1.85,3.26,0.31,0.52,E,-1.85,3.26,0.31,0.53,F,-1.84,3.26,0.31,0.52,G,-1.80,3.26,0.31,0.50,H,-1.80,3.26,0.31,0.50,1.2,局部反应活性,(,前线轨道分布,),最高占有轨道,(HOMO),最低未占轨道,(LUMO),Molecule,A,4N,0.05,1N,0.12,7N,0.16,4N,0.19,8C,0.30,7N,0.18,B,4N,0.04,1N,0.12,7N,0.15,4N,0.19,8C,0.33,7N,0.18,C,4N,0.05,1N,0.12,7N,0.16,4N,0.19,8C,0.30,7N,0.18,D,4N,0.04,1N,0.12,7N,0.15,4N,0.19,8C,0.33,7N,0.18,E,4N,0.05,1N,0.12,7N,0.12,4N,0.19,8C,0.35,7N,0.18,F,4N,0.05,1N,0.12,7N,0.15,4N,0.19,8C,0.32,7N,0.18,G,4N,0.04,1N,0.12,7N,0.16,4N,0.19,8C,0.33,7N,0.18,H,4N,0.05,1N,0.12,7N,0.13,4N,0.19,8C,0.35,7N,0.18,表,3 AH,缓蚀剂分子的,Fukui,指数,1.3,反应活性位点,AH,分子的全电子密度,Fukui,指数可描述分子中各原子的活性强弱,定义为电子密度,对电子数,N,的一阶偏导,分别为亲核攻击指数和亲电攻击指数，,表示分子中原子,i,得,/,给电子能力的强弱。,8,种咪唑啉分子的反应活性区域均分布在分子的咪唑环及其极性官能团上其中,3,个,N,原子为亲电反应中心，咪唑环上成双键结构的,C,、,N,两原子为亲核反应中心。,分子碳链长度对分子的整体反应活性和活性区域分布基本不产生影响。,2,咪唑啉缓蚀剂自组装膜的成膜机理研究,研究目标：,1,、缓蚀剂膜自身的稳定性以及膜与金属表面的结合强度；,2,、分子烷基链长对自组装膜的影响规律。,2.1,吸附表面的选取,碳钢表面,CO,2,腐蚀产物膜的结构示意图,碳钢在含,CO,2,环境中腐蚀产物主要是,FeCO,3,，沉积在金属表面形成,疏松多孔,的,FeCO,3,膜。,模拟过程中选择,Fe,和,FeCO,3,作为吸附表面,FeCO,3,Fe,2.2,缓蚀剂分子与金属表面的相互作用,Molecule,E,adsorption,/kJmol,-1,/,d,/nm,Fe,FeCO,3,Fe,FeCO,3,Fe,FeCO,3,A,510.63,821.19,7.63,6.46,0.297,0.336,B,588.41,858.49,6.71,5.54,0.296,0.350,C,661.42,894.50,5.18,1.65,0.299,0.348,D,714.02,932.23,4.27,1.80,0.291,0.346,E,811.03,957.48,4.98,1.97,0.293,0.326,F,866.96,981.20,4.10,1.48,0.296,0.327G,968.91,1025.73,4.06,1.45,0.306,0.331,H,1021.56,1058.30,4.00,1.37,0.289,0.328,H,2,O,27.38,267.41,33.17,27.74,0.295,0.308,表,4 AH,分子在,Fe,和,FeCO,3,表面的吸附能、取向角,(,),和距离,(,d,),的统计平均值,金属表面,d,Fe,FeCO,3,Molecule,E,adsorption,/kJmol,-1,/,d,/nm,Fe,FeCO,3,Fe,FeCO,3,Fe,FeCO,3,A,510.63,821.19,7.63,6.46,0.297,0.336,B,588.41,858.49,6.71,5.54,0.296,0.350,C,661.42,894.50,5.18,1.65,0.299,0.348,D,714.02,932.23,4.27,1.80,0.291,0.346,E,811.03,957.48,4.98,1.97,0.293,0.326,F,866.96,981.20,4.10,1.48,0.296,0.327,G,968.91,1025.73,4.06,1.45,0.306,0.331,H,1021.56,1058.30,4.00,1.37,0.289,0.328,H,2,O,27.38,267.41,33.17,27.74,0.295,0.308,表,4 AH,分子在,Fe,和,FeCO,3,表面的吸附能、取向角,(,),和距离,(,d,),的统计平均值,Fe,FeCO,3,2.3,缓蚀剂在金属表面的自组装单层膜,俯视图,侧视图,Fe,FeCO,3,Molecule,E,Cohesive,/kJmol,-1,/,D/,nm,Fe,FeCO,3,Fe,FeCO,3,Fe,FeCO,3,A,23.42,28.21,31.47,36.60,0.635,0.599,B,28.45,30.67,39.51,43.14,0.586,0.561,C,40.52,43.96,56.09,61.86,0.526,0.453,D,50.26,55.30,57.97,64.74,0.483,0.439,E,65.51,69.09,60.78,64.79,0.456,0.432,F,78.77,105.53,59.34,67.22,0.453,0.417,G,92.11,119.44,60.28,67.77,0.455,0.414,H,112.92,133.95,64.30,68.36,0.454,0.412,表,5 AH,分子在,Fe,和,FeCO,3,表面单层膜的内聚能,(,E,Cohesive,),、吸附角,(,),和链间距,(,D,),Molecule,E,Cohesive,/kJmol,-1,/,D/,nm,Fe,FeCO,3,Fe,FeCO,3,Fe,FeCO,3,A,23.42,28.21,31.47,36.60,0.635,0.599,B,28.45,30.67,39.51,43.14,0.586,0.561,C,40.52,43.96,56.09,61.86,0.526,0.453,D,50.26,55.30,57.97,64.74,0.483,0.439,E,65.51,69.09,60.78,64.79,0.456,0.432,F,78.77,105.53,59.34,67.22,0.453,0.417,G,92.11,119.44,60.28,67.77,0.455,0.414,H,112.92,133.95,64.30,68.36,0.454,0.412,表,5 AH,分子在,Fe,和,FeCO,3,表面单层膜的内聚能,(,E,Cohesive,),、吸附角,(,),和链间距,(,D,),1,、吸附发生时，分子极性的头部优先吸附于金属表面；而非极性的烷基长链则背离表面形成一层密排结构的疏水膜。,2,、随分子烷基链长的增加，缓蚀剂自组装膜自身的稳定性以及膜与金属基体的结合强度逐步增强。,3,、同种缓蚀剂在,FeCO,3,表面比在,Fe,表面形成 的自组装膜更加稳定。,真空条件下的简单模型尚不能,完全准确,地描述缓蚀剂在金属表面的自组装成膜行为。,理论评价结论为：,ABCDE,FGH,2.4,缓蚀性能的理论评价结果与实验结果的对比,原因：没有考虑溶剂对,缓蚀剂吸附行为的影响,文献实验结果为：,ABCDFGH,3,液相条件下咪唑啉在金属表面吸附的,MD,研究,研究目标：溶剂对缓蚀剂吸附、成膜行为的影响规律。,3.1,计算模型,(,a,),(,b,),(,c,),(,d,),液相条件下缓蚀剂分子在金属表面的初始吸附构型,3.2,液相条件下单分子在金属表面的吸附,水溶液中,A(7),、,C(11),、,E(15),和,H(21),分子在,Fe,和,FeCO,3,表面的平衡吸附构型,Fe,FeCO,3,氨基上的,N,原子易被极性水分子极化成为,(NH3),+,水溶液中,C(11),分子在,Fe,和,FeCO,3,表面的平衡吸附构型,表,6 AH,分子在金属表面,吸附能,、,溶剂化能和形变能,的统计平均值,Molecule,E,adsorption,/kJmol,-1,E,solvent,/kJmol,-1,E,deform,/kJmol,-1,Fe,FeCO,3,Fe,FeCO,3,Fe,FeCO,3,A,235.79,439.69,143.03,136.29,159.12,178.54,B,320.03,506.53,147.79,138.06,186.87,210.40,C,458.17,540.15,143.69,149.68,230.01,215.42,D,440.89,550.59,166.50,168.34,250.86,236.01,E,576.04,636.76,150.47,157.40,271.77,280.60,F,461.02,524.64,215.56,225.36,301.10,296.28,G,365.31,533.95,205.53,222.74,323.04,337.19,H,373.05,522.04,222.27,210.31,345.82,339.44,吸附能、缓蚀效率,与烷基链长的关系曲线,溶剂化能、吸附能,与烷基链长的关系曲线,此消彼长,吸附能,溶剂化能,（反映缓蚀剂分子与水溶剂的相互作用强弱）,形变能反映缓蚀剂分子的形变程度）,3.3,液相条件下缓蚀剂在金属表面的吸附成膜,A(7),、,C(11),、,E(15),和,H(21),缓蚀剂在,Fe,和,FeCO,3,表面吸附成膜的平衡构型,缓蚀性能的理论评价结论为：,AFGH,缓蚀性能的文献实验结果为：,AFGH,液相模型是合理、可靠的,4,腐蚀介质在缓蚀剂膜中扩散行为的,MD,研究,研究目标：,1,、缓蚀剂膜对腐蚀介质粒子扩散的抑制能力；,2,、分析影响缓蚀剂膜抑制能力的决定性因素。,4.1,计算模型,腐蚀介质粒子的结构示意图,缓蚀剂膜中植入一个腐蚀介质粒子的无定形组织结构,4.2,腐蚀介质粒子在缓蚀剂膜的扩散性能,表,8,四种腐蚀介质粒子及,H,2,O,分子在缓蚀剂膜中的扩散系数,Molecule,(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),H,2,O,2.3920*,0.7830,0.3220,0.2330,A(7),0.1488,0.0058,0.0047,0.0050,B(9),0.1228,0.0035,0.0033,0.0028,C(11),0.1112,0.0030,0.0027,0.0023,D(13),0.0792,0.0023,0.0025,0.0018,E(15),0.0638,0.0012,0.0023,0.0011,F(17),0.0663,0.0011,0.0016,0.0009,G(19),0.0643,0.0013,0.0017,0.0011,H(21),0.0652,0.0011,0.0015,0.0010,（,1,）与在水中的扩散系数相比，腐蚀粒子在缓蚀剂膜中的扩散系数大幅度下降，说明缓蚀剂膜能有效抑制腐蚀介质的迁移；,表,8,四种腐蚀介质粒子及,H,2,O,分子在缓蚀剂膜中的扩散系数,Molecule,(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),H,2,O,2.3920*,0.7830,0.3220,0.2330,A(7),01488,0.0058,0.0047,0.0050,B(9),0.1228,0.0035,0.0033,0.0028,C(11),0.1112,0.0030,0.0027,0.0023,D(13),0.0792,0.0023,0.0025,0.0018,E(15),0.0638,0.0012,0.0023,0.0011,F(17),0.0663,0.0011,0.0016,0.0009,G(19),0.0643,0.0013,0.0017,0.0011,H(21),0.0652,0.0011,0.0015,0.0010,（,2,）对于同种缓蚀剂膜，,H2O,分子在其中的扩散系数远远大于,H3O+,、,Cl-,和,HCO3-,的扩散系数，说明膜对正负离子具有更强的扩散抑制能力；,表,8,四种腐蚀介质粒子及,H,2,O,分子在缓蚀剂膜中的扩散系数,Molecule,(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),(10,-9,m,2,/s),H,2,O,2.3920*,0.7830,0.3220,0.2330,A(7),0.1488,0.0058,0.0047,0.0050,B(9),0.1228,0.0035,0.0033,0.0028,C(11),0.1112,0.0030,0.0027,0.0023,D(13),0.0792,0.0023,0.0025,0.0018,E(15),0.0638,0.0012,0.0023,0.0011,F(17),0.0663,0.0011,0.0016,0.0009,G(19),0.0643,0.0013,0.0017,0.0011,H(21),0.0652,0.0011,0.0015,0.0010,（,3,）随烷基链长的增加，,4,种粒子在膜中的扩散系数均呈“大小稳定”的变化趋势：,4.3,腐蚀介质粒子在缓蚀剂膜中扩散的微观机理,自由体积,粒子与膜的相互作用,膜的自扩散能力,4.3.1,自由体积,空间由两部分构成：,一是缓蚀剂分子所占有的空间，其体积称为占有体积；,二是因分子自身结构及空间位阻效应的影响，体系中必定存在分子未占据的空间，而这部分空间所具有的体积则称之为自由体积。,表,9,四种腐蚀介质粒子的范德华半径,Corrosion Particle,Calculated value,/nm,Referrence,values,/nm*,Error,/%,H,3,O,+,0.1375,/,/,H,2,O,0.1425,0.1450,1.72,Cl,-,0.1725,0.1810,4.70,HCO,3,-,0.1975,/,/,Alkyl Chain Length,/%,/%,/%,/%,7(A),12.49,11.33,6.85,4.41,9(B),11.32,10.73,65,3.31,11(C),11.19,10.95,6.23,2.76,13(D),11.08,9.06,5.95,2.54,15(E),10.89,8.96,4.97,2.51,17(F),10.85,8.92,4.94,2.49,19(G),10.82,8.90,4.90,2.48,21(H),10.83,8.89,4.87,2.49,表,10,腐蚀介质粒子在缓蚀剂膜中的自由体积分数,4.3.2,腐蚀介质粒子与缓蚀剂膜的相互作用,腐蚀介质粒子与缓蚀剂膜相互作用能随烷基链长的变化曲线,表,11,腐蚀介质粒子与缓蚀剂膜的相互作用能,Particle,E,total,(kcal/mol),E,total,E,Vdw,(kcal/mol),E,Coulomb,(kcal/mol),H,2,O,-15.44,-1.35,-14.09,H,3,O,+,-87.45,-7.04,-80.41,Cl,-,-95.25,-10.47,-84.78,HCO,3,-,-143.20,-13.98,-129.22,1,2,3,自由体积,粒子与膜的相互作用,粒子的扩散行为,缓蚀性能的理论评价结论为：,ABCDE,F,G,H,缓蚀性能的文献实验结果为：,ABCDFGH,?,4.4,理论预测与实验结果存在差异的原因分析,基本假设：,8,种缓蚀剂分子在水中具有相同的溶解度，而且在金属表面成膜所需时间相同，均可在金属表面形成饱和吸附。,缓蚀剂分子在液相中发挥作用通常经历以下过程：,首先缓蚀剂分子溶解于溶剂中；,缓蚀剂分子扩散到金属表面；,缓蚀剂头部咪唑环与金属表面结合；,缓蚀剂分子长链进行内部优化形成稳定的自组装膜。,表,12 8,种缓蚀剂溶度参数、成膜时间和密度的计算值,Molecule,Chain Length,Solubility Parameter,(cal/cm,2,),1/2,Film Forming Time*,（,hour,）,Density(g/cm,3,),Calculated,Value,Referrence,Values,Calculated,Value,Adjusting,Value,A,7,9.25,/,0.0005,0.872,0.872,B,9,9.25,/,0.0006,0.871,0.871,C,11,9.25,/,0.0007,0.871,0.871,D,13,9.25,/,0.0008,0.870,0.870,E,15,9.20,/,0.0010,0.870,0.870,F,17,8.86,/,0.100,0.867,0.800,G,19,8.68,/,5.900,0.863,0.750,H,21,8.62,/,771.00,0.863,0.700,H,2,O,/,23.20,23.86,/,/,/,对于,Fe,和,FeCO,3,两种表面，当烷基链长分别大于,13,和,15,时，缓蚀剂在金属表面才能形成,高覆盖度,、,致密的缓蚀剂膜,，可降低,FeCO,3,表面的孔隙度，抑制,Fe,表面的阴阳极反应。,结 论,咪唑啉分子的反应活性区域和活性位点主要集中在,分子的头部,。烷基碳链长度对分子的反应活性强弱和分布基本不产生影响。,1,2,3,溶剂化效应,是影响缓蚀剂缓蚀性能的重要因素。当分子烷基链长为,15,时，可形成致密的疏水膜，能有效覆盖金属表面，因而具有最好的缓蚀性能；而当烷基链较短或较长时，膜疏松多空，缓蚀性能较差。,4,自由体积,和,腐蚀粒子与膜的相互作用,是影响缓蚀剂膜抑制腐蚀粒子扩散的,2,个决定性因素。相对于短链分子，长链分子膜对腐蚀粒子具有更好的扩散抑制能力。,5,分子模拟方法的局限性。由于受计算机硬件、理论方法和模拟软件的限制，目前通过分子模拟真实再现缓蚀剂的溶解、扩散和成膜过程还存在许多技术上的困难，对此还有待于开展进一步的研究工作。,结束,此课件下载可自行编辑修改，供参考！,感谢您的支持，我们努力做得更好！,