一种新型联苯双子季铵盐缓蚀剂的合成及性能研究

以甲基丙烯酸二甲氨基乙酯和联苯二氯苄为原料通过季铵化的方法合成双子缓蚀剂BDMA,再以失重实验、电化学阻抗谱、Tafel、形貌、量子化学计算的方法,对Q235钢在含有不同浓度BDMA盐酸中的缓蚀性能进行评价。通过缓蚀率实验可知,30℃时BDMA的缓释率能达到98.8%,说明其具有较优异的缓蚀效果;电化学实验结果表明,缓蚀剂的加入使其保护膜变厚,缓蚀率与浓度成正比;由吸附热力学知,BDMA的吸附属于自发,放热过程,且主要为化学吸附,符合郎格缪尔等温式;量子化学计算可知该缓蚀剂上面有较多吸附位点。     

棉竹竹叶提取物在HCl中对钢和铝的缓蚀作用

采用失重法和动电位极化曲线首次研究了棉竹竹叶提取物在1.0 mol/LHCl溶液中对冷轧钢和工业纯铝的缓蚀作用。结果表明：棉竹竹叶提取物对冷轧钢具有非常好的缓蚀作用,最大缓蚀率达95%,且在钢表面的吸附符合Langmuir吸附等温式;对铝具有中等程度的缓蚀作用,最大缓蚀率仅为55%,在铝表面的吸附也服从Langmuir吸附模型。极化曲线表明竹叶缓蚀剂为混合抑制型缓蚀剂。     

2,5-二芳基-1,3,4-噻二唑衍生物的合成及缓蚀性能

合成4种2,5-二芳基-1,3,4-噻二唑化合物,即2,5-二苯基-1,3,4-噻二唑(DPTD),2,5-二(2-羟基苯)-1,3,4-噻二唑(2-DHPTD),2,5-二(3-羟基苯)-1,3,4-噻二唑(3-DHPTD)和2,5-二(4-羟基苯)-1,3,4-噻二唑(4-DHPTD)。通过Tafel极化曲线和电化学阻抗研究4种油溶型噻二唑衍生物在50 mg·L^-1硫-乙醇体系中的缓蚀性能,电化学测试表明:腐蚀液中添加噻二唑衍生物后,银片腐蚀得到抑制;随着缓蚀剂浓度增大,腐蚀电流密度减小,缓蚀效率增大;当缓蚀剂浓度为90 mg·L^-1时,4种缓蚀剂DPTD、2-DHPTD、3-DHPTD和4-DHPTD的缓蚀效率分别为85.8%、94.6%、96.4%和97.1%。采用扫描电子显微镜和原子力显微镜观察其表面形貌,可知缓蚀剂在金属表面形成一层保护膜,阻止腐蚀物质与金属表面的接触,从而抑制银片腐蚀。经分子动力学分析可知,4种噻二唑衍生物吸附于金属表面遵循Langmuir等温方程,且吸附属于以化学吸附为主的混合型吸附。量子化学计算和分子动力学模拟研究表明,4种缓蚀剂均具有很好的缓蚀作用,且4种缓蚀剂的缓蚀效率大小顺序是[4-DHPDT]> [3-DHPDT]> [2-DHPDT]> [DPDT],这与实验结果一致。     

钼酸盐和钨酸盐在HCl中对冷轧钢的缓蚀作用

用失重法和动电位极化曲线法研究了在0．2mol／L HCl介质中，钼酸钠（Na2MoO4）、钨酸钠（Na2WO4）对冷轧钢片的吸附及其缓蚀作用。实验结果表明，在酸性溶液中，钼酸盐、钨酸盐均对冷轧钢片具有较好的缓蚀作用，而且用量很低。缓蚀剂在钢表面的吸附符合Langmuir吸附方程。在相同条件下，对比了钼酸钠、钨酸钠对冷轧钢的缓蚀作用，发现缓蚀率取决于缓蚀剂的质量浓度，当缓蚀剂浓度极低时缓蚀率排序为：钼酸钠〈钨酸钠，但在较大缓蚀剂质量浓度范围内钼酸钠表现出优越的缓蚀性能。动电位极化曲线表明，钼酸盐、钨酸盐在HCl中为混合抑制型缓蚀剂。     

有机添加剂对锌在碱液中的缓蚀作用研究

通过析氢实验、Tafel极化曲线和交流阻抗图研究了癸醇磷酸酯钾盐(A)、癸醇聚氧乙烯(3)醚磷酸酯钾盐(B)和癸醇聚氧乙烯(8)醚磷酸酯钾盐(C)三种缓蚀剂对锌在KOH溶液中的缓蚀作用，缓蚀剂C可使析氢量减至33．1％，缓蚀效率可达78．7％。缓蚀性能受缓蚀剂浓度和结构的影响。     

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。     

过期药呋塞米在醋酸溶液中对冷轧钢的缓蚀作用

通过电导率测量、pH测量、同步热分析(STA)、Tafel极化曲线法和电化学交流阻抗谱法研究了不同浓度和温度下过期药呋塞米在1 mol/L的醋酸溶液中对冷轧钢缓蚀作用。实验结果表明:过期药呋塞米在1 mol/L的醋酸溶液中对冷轧钢有较好的缓蚀效果,且缓蚀率随着缓蚀剂浓度和温度的增加而增大。该缓蚀剂在醋酸中对钢是一种抑制阴极和阳极的混合型缓蚀剂。缓蚀剂在冷轧钢表面的吸附符合Langmuir吸附等温式,其吸附是自发、物理吸附过程。同步热分析还说明了该缓蚀剂易稳定吸附在冷轧钢表面。     

1.4-二(1'-硫氰铵基乙基-2'-咪唑啉基)苯缓蚀剂的合成及其缓蚀性能的研究

以对苯二甲酸和二乙烯三胺为原料,采用阶梯升温法合成了1.4-二(1'-胺乙基-2'-咪唑啉基)苯中间体,通过正交实验法,研究了中间体与硫脲高温重排反应合成了1.4-二(1'-硫氰铵基乙基-2'-咪唑啉基)苯的最优合成条件。采用元素分析和红外光谱表征了产物的结构。正交实验得到的最佳合成条件为:中间体与硫脲的摩尔比为1∶2.2,温度为150℃,溶剂为N,N-二甲基甲酰胺,反应时间为4 h,产率为77.2%。采用静态失重法和电化学极化曲线法研究了该缓蚀剂的缓蚀性能,静态失重缓蚀实验结果表明,在5%盐酸介质中,药剂用量为100 mg/L、酸性介质温度为60℃、腐蚀时间为6 h的实验条件下,对Q235钢缓蚀率为93.7%。电化学极化曲线测定结果表明,缓蚀剂是一种阴极型缓蚀剂。吸附热力学研究表明,该缓蚀剂的吸附等温线符合Langmuir吸附等温式。     

元宝枫叶提取物在盐酸溶液中对钢的缓蚀性能研究

天然植物元宝枫(acer truncatum)叶的提取物可作为一种环境友好型缓蚀剂.采用失重法、动电位极化曲线和交流阻抗(EIS)研究了元宝枫叶提取物在1.0mol/L HCl溶液中对冷轧钢的缓蚀作用.结果表明:元宝枫叶提取物对冷轧钢具有良好的缓蚀作用,且在钢表面的吸附符合Langmuir吸附等温式.极化曲线表明,元宝枫提取物为阴极抑制型缓蚀剂;EIS谱呈半圆容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.     

1.4-二(1'-硫氰铵基乙基-2'-咪唑啉基)苯缓蚀剂的合成及其缓蚀性能的研究

以对苯二甲酸和二乙烯三胺为原料,采用阶梯升温法合成了1.4-二(1'-胺乙基-2'-咪唑啉基)苯中间体,通过正交实验法,研究了中间体与硫脲高温重排反应合成了1.4-二(1'-硫氰铵基乙基-2'-咪唑啉基)苯的最优合成条件。采用元素分析和红外光谱表征了产物的结构。正交实验得到的最佳合成条件为:中间体与硫脲的摩尔比为1∶2.2,温度为150℃,溶剂为N,N-二甲基甲酰胺,反应时间为4 h,产率为77.2%。采用静态失重法和电化学极化曲线法研究了该缓蚀剂的缓蚀性能,静态失重缓蚀实验结果表明,在5%盐酸介质中,药剂用量为100 mg/L、酸性介质温度为60℃、腐蚀时间为6 h的实验条件下,对Q235钢缓蚀率为93.7%。电化学极化曲线测定结果表明,缓蚀剂是一种阴极型缓蚀剂。吸附热力学研究表明,该缓蚀剂的吸附等温线符合Langmuir吸附等温式。     

Corrosion control of Cu-Ni alloys in neutral chloride solutions by amino acids

The corrosion inhibition of Cu-Ni alloys was investigated in aqueous chloride solutions using amino acids as environmentally safe materials. The corrosion rate was calculated in absence and presence of the corrosion inhibitor using polarization and impedance techniques. The inhibition efficiency of the different amino acids was also calculated.The experimental results have shown that a simple amino acid like glycine can be used as efficient corrosion inhibitor for the Cu-Ni alloys in neutral chloride solutions. An inhibition efficiency of about 85% could be achieved at very low concentrations of the amino acid (0.1 mM). For low Ni content alloy (Cu-5Ni), 2.0 mM cysteine shows a remarkable high (∼96%) corrosion inhibition efficiency. The experimental impedance data were fitted to theoretical data according to a proposed equivalent circuit model for the electrode/electrolyte interface, and the mechanism of the corrosion inhibition process was suggested. Different adsorption isotherms were tested and the corrosion inhibition process was found to depend on the adsorption of the amino acid molecules and/or the deposition of corrosion products on the alloy surface. The adsorption free energy of cysteine on Cu-5Ni (−37.81 kJ mol⁻¹) reveals a strong physical adsorption of the inhibitor on the alloy surface.     

INHIBITION OF MILD STEEL CORROSION IN SULFURIC ACID MEDIUM BY HYDROXYETHYL CELLULOSE

The inhibitive effect of hydroxyethyl cellulose (HEC) on mild steel corrosion in aerated 0.5 M H₂SO₄ solution was studied using gravimetric and electrochemical techniques. The effect of temperature on corrosion and inhibition was also investigated. The results show that hydroxyethyl cellulose functioned as a good inhibitor in the studied environment and inhibition efficiency increased with concentration of inhibitor. Potentiodynamic polarization measurements revealed that HEC inhibited both the cathodic and anodic partial reactions of the corrosion processes. Impedance results clearly show that HEC inhibited the corrosion reaction by adsorption onto the metal/solution interface by significantly decreasing the double layer capacitance (C _dl ). This result was greatly pronounced in the presence of the inhibitor system (HEC + KI) that contains halide additive. Temperature studies revealed an increase in inhibition efficiency with rise in temperature. The adsorption behavior was found to obey the Freundlich isotherm. The values of activation energy, heat of adsorption, and standard free energy suggest that there was transition from physical to chemical adsorption mechanism of HEC on the mild steel surface. Quantum chemical calculations using the density functional theory (DFT) was employed to determine the relationship between molecular structure and inhibition efficiency.     

含咪唑环不对称双季铵盐的合成及缓蚀性能研究

成功合成了含咪唑环不对称双季铵盐,通过失重法、电化学阻抗谱、动电位扫描极化曲线、扫描电镜对合成产物在3%Na Cl的饱和二氧化碳溶液中的缓蚀效率进行研究。结果表明,其在饱和二氧化碳溶液中对钢铁有着良好的缓蚀作用,缓蚀效率接近90%;运用Langmuir吸附等温式对吸附行为进行了拟合,表明其吸附类型符合Langmuir吸附模型,吸附方式为化学吸附。     

Adsorption, synergistic inhibitive effect and quantum chemical studies of ampicillin (AMP) and halides for the corrosion of mild steel in H2SO4

The corrosion inhibition of ampicillin (AMP) and its synergistic combination with halides (KI, KCl and KBr) for the corrosion of mild steel in H₂SO₄ have been investigated using gravimetric, gasometric, thermometric and infrared (IR) methods. The inhibition efficiencies of AMP for the corrosion of mild steel increased with increase in concentration but decreased with rise in temperature. The adsorption of AMP on the mild steel surface was found to obey the Langmuir adsorption isotherm model. The combination of AMP with the halides (KI, KBr and KCl) enhanced the inhibition efficiency and adsorption behavior of the inhibitor indicating synergism. The inhibition efficiency of AMP increased with increasing concentration and the adsorption of the inhibitor was spontaneous. Physical adsorption mechanism has been proposed from the thermodynamic data obtained. There was a significant correlation between the inhibition efficiency of AMP and some quantum chemical parameters (R ² = 0.96) using the quantitative structure–activity relationship (QSAR) method. Some quantum chemical parameters and the Mulliken charge densities on the optimized structure of AMP were calculated using the B3LYP/6-31G (d,p) basis set method to provide further insight into the mechanism of the corrosion inhibition process.     

Starch-AA-CS三元共聚物对酸溶液中碳钢的缓蚀作用

以淀粉（Starch）、丙烯酸（AA）和壳聚糖（CS）为原料合成三元共聚物（SAAC）。利用红外光谱（FT-IR）和X射线衍射（XRD）进行结构表征,并通过电化学方法、失量法、扫描电子显微镜（SEM）和能谱仪（EDS）研究SAAC在1 mol·L^-1 HCl环境下对Q235碳钢的缓蚀作用及机理。结果显示,SAAC是一种混合型缓蚀剂,30℃时,200 mg·L^-1的SAAC的缓蚀率可达90.1%。通过Gibbs自由能和Tafel曲线可知,SAAC在Q235碳钢表面的吸附符合Langmuir吸附等温式,同时存在物理吸附与化学吸附。SAAC合成原料经济、环保,合成条件温和,是一种具有广泛应用前景的绿色环保型缓蚀剂。     

Influence of H+ and Cl− ions on inhibitive performance of poly(aniline) for iron corrosion in acid

The inhibition effect of poly(aniline) on pure iron corrosion in 1M HCl and with various H⁺ ions and Cl^? ions concentrations was investigated by the polarization and electrochemical impedance spectroscopy methods. The results showed that poly(aniline) suppressed both cathodic and anodic processes of iron dissolution in 1M HCl by its adsorption on the iron surface according to Langmuir's adsorption isotherm. The inhibition efficiency of poly(aniline) was found to increase with the inhibitor concentrations. Further, it was observed that, there was no significant variation in corrosion potential (E_corr) values in the presence of inhibitors suggesting that, this polymer behaved as mixed type inhibitor. Similar studies for the inhibitor at 500 ppm in various concentrations of H⁺ and Cl^? ions, have shown that the inhibition efficiency decreases with decrease in concentrations of H⁺ ions and Cl^? ions in aqueous solution. It reveals that, the adsorption of inhibitor on iron surface is by more cationic form of inhibitor and higher efficiency at higher H⁺ and Cl^? ions is due to enhanced adsorption of cat ionic form of inhibitor molecules. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

苯并咪唑类缓蚀剂缓蚀机理以及研究趋势

苯并咪唑类缓蚀剂是一类盐酸酸洗缓蚀剂,当取代基不同,其分子呈现不同的缓蚀效率。苯并咪唑类缓蚀剂具有高效、低毒和生物易降解等特点。苯并咪唑缓蚀剂是吸附型缓蚀剂,它涉及到阻化效应、分子界面吸附、基团覆盖效应和氢键缔合效应等多方面。文中介绍了苯并咪唑类缓蚀剂的制备方式、缓释机理以及发展状况。     

一种新型联吡啶双子季铵盐的合成及缓蚀性能

以4,4'-联吡啶和氯化苄为原料,经季铵化反应制备了化合物1,1?-二苄基-4,4?-联吡啶双子季铵盐(PBA),产率为76.3%,通过FTIR、~1HNMR对产物结构进行了表征;利用失重法、电化学技术、AFM考察了PBA对1 mol/L盐酸溶液中Q235钢的缓蚀作用和其在Q235钢表面的吸附行为。结果表明,PBA是一种同时抑制阴、阳极的混合型缓蚀剂,缓蚀率随PBA浓度的增加而增加,随温度的升高而略有降低。当PBA质量浓度为80 mg/L时,缓蚀率可达96.53%。PBA在Q235钢表面的吸附为放热反应,遵循Langmuir等温式,是以化学吸附为主的混合型吸附。PBA在钢表面形成了一层致密的保护膜,大大阻碍了钢腐蚀。使用量子化学法研究了PBA的缓蚀机理,结果表明,PBA的活性区域集中于苯环和杂环上,且PBA分子接受电子的能力大于提供电子的能力。     

Adsorption and corrosion inhibition behaviour of N-(phenylcarbamothioyl)benzamide on mild steel in acidic medium

Corrosion inhibition property of N-(phenylcarbamothioyl)benzamide (PCB) on mild steel in 1.0 M HCl solution has been investigated using chemical (weight loss method) and electrochemical techniques (potentiodynamic polarization and AC impedance spectroscopy). The inhibition efficiencies obtained from all the methods are in good agreement. The thiourea derivative is found to inhibit both anodic and cathodic corrosion as evaluated by electrochemical studies. The inhibitor is adsorbed on the mild steel surface according to Langmuir adsorption isotherm. The adsorption mechanism of inhibition was supported by spectroscopic (UV-visible, FT-IR, XPS), and surface analysis (SEM-EDS) and adsorption isotherms. The thermodynamic parameter values of free energy of adsorption (ΔG_ads) reveals that inhibitor was adsorbed on the mild steel surface via both physisorption and chemisorption mechanism.