4种吡嗪类缓蚀剂及其在Cu(111)面吸附行为的密度泛函理论研究

为了探究吡嗪类缓蚀剂对铜的缓蚀机理,对比研究4种缓蚀剂的吸附性能。采用基于密度泛函理论(DFT)的量子化学方法,研究了4种吡嗪类缓蚀剂分子的反应活性及其在Cu(111)面的吸附行为,结果表明:4种缓蚀剂分子的前线轨道均分布在吡嗪环上,且吡嗪环上的N原子为分子的反应活性中心;4种吡嗪类缓蚀剂分子均能与Cu原子发生化学吸附形成共价键,且吸附强度排序为2-氨基吡嗪(AP)2-氨基-5-溴吡嗪(ABP)2-甲基吡嗪(MP)吡嗪(PY);另外,缓蚀剂分子也可以通过静电相互作用与金属表面发生物理吸附。     

4种吡嗪类缓蚀剂及其在Cu(111)面吸附行为的密度泛函理论研究

为了探究吡嗪类缓蚀剂对铜的缓蚀机理,对比研究4种缓蚀剂的吸附性能。采用基于密度泛函理论（DFT）的量子化学方法,研究了4种吡嗪类缓蚀剂分子的反应活性及其在Cu（111）面的吸附行为,结果表明：4种缓蚀剂分子的前线轨道均分布在吡嗪环上,且吡嗪环上的N原子为分子的反应活性中心;4种吡嗪类缓蚀剂分子均能与Cu原子发生化学吸附形成共价键,且吸附强度排序为2-氨基吡嗪（AP）> 2-氨基-5-溴吡嗪（ABP）> 2-甲基吡嗪（MP）> 吡嗪（PY）;另外,缓蚀剂分子也可以通过静电相互作用与金属表面发生物理吸附。     

对称型双季铵盐在15%盐酸中对N80钢的缓蚀作用

用三种不同链长的双卤代烃与α-甲基吡啶制备了三种新型的双季铵盐,采用核磁氢谱对其结构表征。分别通过静态失重腐蚀试验、电化学极化曲线和交流阻抗谱(EIS)测定其在15%盐酸中对N80钢的缓蚀作用。腐蚀试验结果表明,随分子中疏水链的增长缓蚀效果逐步提高,溴化1,8-二(α-甲基吡啶)辛烷(BMHD-8)缓蚀效果最佳,浓度为1.5×10~(-2) mol·L~(-1)时,在15%HCl、25℃下对N80钢的缓蚀率达92.0%。电化学实验说明所合成的缓蚀剂属于混合型缓蚀剂。缓蚀剂分子会在N80钢表面形成吸附膜,吸附行为符合Langmuir吸附模型,且同时存在物理与化学两种吸附类型。     

理论研究溴化-N-烷基吡啶炔丙醇类缓蚀剂的缓蚀性能

本文使用密度泛函理论和分子动力学模拟两种方法,从理论上研究了我们实验室自制的三种缓蚀剂(即m-6,m-8和m-10)对低碳钢的缓蚀性能。量子化计算结果表明,三种缓蚀剂分子具有较高的反应活性,m-10在腐蚀抑制过程中反应活性最高。分子动力学(MD)模拟表明三种缓蚀剂分子都能与铁表面相互作用,m-10在铁表面的吸附能力最强。理论计算结果表明,m-n缓蚀性能的大小为:m-10m-8m-6。     

曼尼希碱的结构与其缓蚀性能的关系

利用曼尼希反应制得了曼尼希碱1-苯基-3-二乙氨基-1-丙酮(DPO),再利用DPO和伯胺(苄胺、对甲基苯胺、苯胺)进行胺交换反应,制得了结构不同的曼尼希碱:1-苯基-3-苄氨基-1-丙酮(BPO)、1-苯基-3-对甲苯氨基-1-丙酮(TPO)和1-苯基-3-苯氨基-1-丙酮(PPO)。静态失重法和极化曲线法研究结果表明,其在15%盐酸中90℃时对N80钢的缓蚀性能大小顺序为:DPOBPOTPOPPO。四种曼尼希碱缓蚀剂在N80钢表面上的吸附遵循Langmuir吸附模型,吸附能力大小顺序为:DPOBPOTPOPPO,这说明当曼尼希碱分子中氨基与苯环形成富电子共轭体系时,其吸附能力较强,可表现出较强的缓蚀性能。     

曼尼希碱的结构与其缓蚀性能的关系

利用曼尼希反应制得了曼尼希碱1-苯基-3-二乙氨基-1-丙酮(DPO),再利用DPO和伯胺(苄胺、对甲基苯胺、苯胺)进行胺交换反应,制得了结构不同的曼尼希碱:1-苯基-3-苄氨基-1-丙酮(BPO)、1-苯基-3-对甲苯氨基-1-丙酮(TPO)和1-苯基-3-苯氨基-1-丙酮(PPO)。静态失重法和极化曲线法研究结果表明,其在15%盐酸中90℃时对N80钢的缓蚀性能大小顺序为:DPO相似文献   

4-氨基苯甲酸席夫碱自组装缓蚀膜对20#钢在饱和CO2油田水中的缓蚀性能

利用邻氧乙酸苯甲醛缩4-氨基苯甲酸钾盐席夫碱(K₂L1)缓蚀剂在20#碳钢表面制备了自组装单分子膜(SAMs),通过电化学方法研究了缓蚀剂的合成条件、自组装时间等因素对成膜的影响,结果表明,合成中KOH与邻氧乙酸苯甲醛按2:1摩尔比进行反应得到的K₂L1缓蚀剂在碳钢表面自组装3 h后,可以形成稳定、致密的缓蚀膜。缓蚀性能的研究表明,碳钢表面K₂L1-SAMS抑制了碳钢的阴极还原过程,改变了电极表面双电层结构,具有良好的缓蚀效果(最高缓蚀效率可达95%以上),交流阻抗和极化曲线得到的结论是一致的。同时研究表明K₂L1的吸附行为符合Langmuir吸附等温式,吸附机理是典型的化学吸附。量子化学计算结果表明,K₂L1分子具有多个吸附活性中心,这些活性原子的前线轨道能与碳钢表面铁原子的前线轨道相互作用,因而使得K₂L1分子在碳钢表面形成吸附膜,阻止了碳钢在饱和CO₂油田水介质中的溶解。X射线光电子能谱(XPS)分析表明,K₂L1通过配位键在碳钢表面形成了稳定的缓蚀膜。     

噻二唑衍生物分子结构与其缓蚀性能的关系

利用交流阻、Tafel极化曲线和原子力显微镜（AFM）,研究2-氨基-1,3,4-噻二唑（ATD）、5-甲基-2-氨基-1,3,4-噻二唑（MATD）、5-苯基-2-氨基-1,3,4-噻二唑（PATD）和2,5-二苯基-1,3,4-噻二唑（DPTD）4种具有不同取代基的噻二唑衍生物在50 mg·L^-1硫溶液中对金属银的缓蚀性能。实验结果表明：缓蚀剂成功地吸附到了金属表面,金属腐蚀受到明显的抑制,且4种缓蚀剂的缓蚀效率的大小顺序是：MATD>PATD>ATD>DPTD。位于噻二唑环2,5位置上非极性和极性基团结构的变化,极性基团均对缓蚀剂的缓蚀性能有较大影响。因极性基团更容易吸附到金属表面,所以当噻二唑环上存在极性基团时,其抗腐蚀性能明显增强;当环上存在非极性基团时,与芳基相比,非极性基团为烷基时,其缓蚀性能更好,原因可能是由于芳基的体积较大,在吸附过程中受到的阻力较大。通过动力学分析可知：4种缓蚀剂在金属表面的吸附遵循Langmuir吸附等温方程,吸附类型属于化学吸附为主的混合吸附。通过分子动力学模拟,进一步研究了4种缓蚀剂的抗腐蚀机理,结果表明缓蚀剂与金属界面发生吸附时,4种缓蚀剂的噻二唑环和环上亲水支链中的极性基团优先吸附到金属银表面,理论计算和实验结果一致。     

醛/氨反应合成吡啶碱机理

在常压釜式反应器中,以乙酸为溶剂,开展了乙酸铵(氨源)与甲醛、乙醛和丙烯醛中的一种或多种反应制备吡啶碱的研究。通过Hückel和Mulliken模型的量子化学和热力学计算,分析了丙烯醛和反应中间体丙烯亚胺的构型和电荷,考察了生成中间体二氢吡啶和产物3-甲基吡啶过程中的静电相互作用、前线分子轨道和能量变化,从而提出了丙烯醛/氨合成3-甲基吡啶的反应机理,并总结了醛/氨反应制吡啶碱反应的一般规律。理论预测的产物组成与实验结果具有良好的一致性。     

多吸附位点席夫碱缓蚀剂的合成及缓蚀效果

以4-三氟甲基苯甲醛与乙二胺为原料,经Schiff反应合成了席夫碱化合物(BEA),反应条件:反应温度为65℃,n(乙二胺)∶n(4-三氟甲基苯甲醛)=5∶1,反应时间为6 h;BEA与均苯三甲酰氯经酰胺化反应合成了多吸附位点席夫碱缓蚀剂(BTA),反应条件:反应温度为50℃,n(BEA)∶n(均苯三甲酰氯)=3.3∶1,反应时间为8 h。采用静态挂片失重法、电化学法和扫描电子显微镜(SEM)研究BEA和BTA对P110钢在1 mol/L盐酸中的缓蚀性能。失重法研究表明,当缓蚀剂质量浓度为200 mg/L时,BTA缓蚀率达99.39%,BEA的缓蚀率仅94.29%;等温吸附行为研究结果表明,缓蚀剂分子能自发地吸附于P110钢表面,满足Langmuir吸附模型;电化学法研究结果表明,BTA属于阳极控制型,在金属表面形成保护性膜,能有效抑制金属腐蚀。因此,多吸附位点缓蚀剂BTA缓蚀性能优于BEA。     

6种燕尾形苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理理论研究

为了研究燕尾型苝二酰亚胺类双子表面活性剂对碱性锌电极缓蚀机理,利用密度泛函理论（DFT）和分子动力学模拟（MD）方法,探讨了两类共6种燕尾型苝二酰亚胺类双子表面活性剂的吸附行为。DFT计算结果表明,前线分子轨道分布主要位于分子核心的苝二酰亚胺骨架上,且苝二酰亚胺骨架上的N原子为分子的反应活性中心。分子动力学模拟表明,6种燕尾型苝二酰亚胺类双子表面活性剂均能与水溶液中的金属锌表面发生相互作用,N₂、P₂在两类双子表面活性剂中均表现出有较高的吸附能和较大的扩散系数,吸附能分别为-11315.868 kcal/mol、-10785.698 kcal/mol,扩散系数分别为2.5、1.32;研究结果同时表明,N₂和P₂形成的双子表面活剂膜层对腐蚀粒子OH^-的阻止效果较好,能够在金属锌表面起到很好的缓蚀效果。     

Pongamia Pinnata as a Green Corrosion Inhibitor for Mild Steel in 1N Sulfuric Acid Medium

Due to the harmful nature of the traditional inhibitors, in recent years researchers have an interest in using eco-friendly corrosion inhibitors. The plant extracts exhibit efficient corrosion inhibition properties due to the presence of a mixture of organic constituents starting from terpenoids to flavonoids. In the present study the inhibition of corrosion of mild steel in 1N H₂SO₄ solution using the leaf extract of Pongamia pinnata (P. pinnata) was investigated by the weight loss method, potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS) technique. Characterization of the leaf extract of P. pinnata was carried out using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GCMS) analysis. The effect of temperature and immersion time on the corrosion behavior of mild steel in sulfuric acid with different concentrations of P. pinnata was also studied. From the results it was found that the inhibition is mainly attributed to the adsorption of inhibitor molecules on the mild steel electrode surface. It was found that the adsorption of inhibitor molecules takes place according to the Langmuir, Temkin, and Freundlich adsorption isotherms. Kinetic as well as thermodynamic parameters were calculated, also confirming the strong interaction between inhibitor molecules and the electrode surface. The inhibition efficiency (I.E in %) was found to increase with increase in concentration of the inhibitor molecules and the maximum inhibition efficiency was attained at 100 ppm of the leaf extract. From the electrochemical studies it was found that the corrosion process was controlled by a mixed inhibition process and single charge transfer mechanism. Fourier transform infrared spectroscopy (FTIR) provided the confirmatory evidence for the adsorption of the extract molecules on the mild steel surface, which is responsible for the corrosion inhibition. Scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) experiments also confirmed the presence of inhibitor molecules on the mild steel surface. From all these experimental results, it can be concluded that the leaf extract of P. pinnata acted as a good corrosion inhibitor for mild steel in 1N sulfuric acid medium even at lower inhibitor concentrations.     

Inhibition Effects of a Synthesized Novel 4-Aminoantipyrine Derivative on the Corrosion of Mild Steel in Hydrochloric Acid Solution together with Quantum Chemical Studies

1,5-Dimethyl-4-((2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-one (DMPO) was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on mild steel in 1.0 M HCl were investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, open circuit potential (OCP) and electrochemical frequency modulation (EFM). The results showed that DMPO inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the mild steel surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis, FT-IR and NMR spectral analyses. Electronic properties such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively) and dipole moment (μ) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but with a decrease in the ELUMO value.     

Surface characterization of molecules at pt(111) using leed, auger, hreels and electrochemistry in ultrahigh vacuum

Reviewed in this article is surface characterization of organic molecules adsorbed at well-defined Pt(111) electrode surfaces from aqueous solution. Among the metal electrodes and surface-structure sensitive properties studied in this work are those involving electrocatalytic activity, such as platinum metal. Platinum is one of the most interesting materials for study in view of its exceptional spectrum of catalytic properties and its good stability in various electrolytic media. The compounds investigated were: (1) 4-Phenylpyridine (4PPY), (II) 4,4′-Bipyridyl (44BPY), (III) 2-Phenylpyridine (2PPY), (IV) 2-2′ Bibyridyl (22BPY), (V) Pyridazine (PD), and (VI) 4-Pyridazinecarboxylic acid (4PDCA). For (I) and (II), the pyridine ring binds to the Pt(111) surface in a tilted, nearly vertical orientation having a pendant phenyl ring, and is virtually unreactive toward electrochemical oxidation. However, (III) and (IV) attach to Pt(111) with their pyridine ring vertically oriented and N-attached, while the other aromatic ring is oriented parallel to the electrode surface. Similarly, (V) and (VI) are attached to Pt(111) through their ring nitrogen atom, with a tilted-vertical orientation and average ring-to-surface angles ranging from 73° to 86°. Compounds (I-VI) were studied in order to understand the influence of molecular structure on surface bonding, molecular orientation, electronic structure, and electrochemical reactivity at well-defined surfaces such as Pt(111), as a function of pH, electrode potential and adsorbate concentration.     

月桂基咪唑啉对Q235钢的缓蚀吸附作用

采用失重法和电化学方法研究了月桂基咪唑啉（IM-11）、1-氨乙基-2-月桂基咪唑啉（AIM-11）和1-羟乙基-2-月桂基咪唑啉（HIM-11）三种化合物在CO₂饱和的3%NaCl溶液中对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为。结果显示,3种化合物均具有较好的抗相似文献   

Understanding the inhibitory effect of sodium oleate on the corrosion of Al and Al–Cu alloys in 1.0 M H<Subscript>3</Subscript>PO<Subscript>4</Subscript> solution—Polarization studies

Polarization measurements were employed, as a first step towards studying the corrosion behaviour of Al and two Al–Cu alloys, namely Al–4.5%Cu, and Al–7.5%Cu alloys in deaerated stirred 1.0 M H₃PO₄ solution at 25 °C. Inhibition of Al and Al–Cu alloys corrosion in 1.0 M H₃PO₄ solution, using sodium oleate (SO) as an anionic surfactant inhibitor, was also studied. Polarization curves showed that SO acted as a mixed-type inhibitor to Al corrosion, while it acted mainly as a cathodic inhibitor to the acid corrosion of Al–4.5%Cu, and Al–7.5%Cu alloys. Inhibition is accomplished by inhibitor adsorption on the electrode surface without detectable changes in the chemistry of corrosion. The relationship between surfactant concentration, surfactant critical micellar concentration (CMC), and corrosion inhibition is also discussed based on the Langmuir isotherm assumption, commonly applied in corrosion inhibition evaluations. The protection efficiency increases with increase in surfactant concentration and %Cu in Al samples. Maximum protection efficiency of the surfactant is observed at concentrations around its CMC. The mechanism of adsorption is discussed based on the surface charge of the electrode surface.     

Study on the effect of vanillin on the corrosion inhibition of aluminum alloy

The effect of vanillin on the corrosion inhibition of aluminum (Al) alloy in seawater was studied by potentiodynamic polarization (PP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology after its exposure to seawater with and without vanillin was examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). All the studied parameters showed good inhibitive characteristics against the corrosion of Al alloy in the tested solution, and their performance was observed to increase with the inhibitor concentration. Polarization data indicated that the studied inhibitor is a mixed-type inhibitor. Linear polarization and EIS studies showed that there were significant increases in the overall resistance after the addition of vanillin. The adsorption of inhibitor on Al alloy was found to obey the Langmuir adsorption isotherm. The analysis of SEM and EDS confirmed the formation of precipitates of vanillin on the metal surface, which reduced the overall corrosion reaction.