四氮唑类化合物和嘧啶类化合物对钢在酸中的缓蚀协同效应及机理研究

Studying on the synergistic inhibition effect is colsely related to exploitating the highly effective composite corrosion inhibitors, and it is research hotspot,key point and difficult issue in the research field of corrosion inhibitor all the time. In this project, the synergistic inhibition effect and its mechanism of tetrazole compound and pyrimidine compound on the corrosion of steel in acid solutions (inorganic acids and organic acids) are studied by weight loss method, electrochemical technique, advanced instrumental analyst on metal surface, quantum chemcial calculation and molecular dynamic simulation. Through screening, a series of composite systems of synergism between tetrazole compound and pyrimidine compound are found. The new important data of the synergistic inhibition effect are accumulated. It is hoped to reveal the effects of composite inhibitor concentration, temperature, acid concentration, corrosion immersion time and the oder of adding chemical reagent on the inhibitive performance of tetrazole compound/pyrimidine compound mixture. The adsorption isotherm of inhibitor on steel surface can be obtained via fitting with the experimental data. The adsorption thermodynamic parameters and corrosion kinetic parameters are calculated. Combined these parameters with the electrochemical reults, it is to elucidate the adsorption behavior of inhibitor on steel surface and the electrochemical mechanism before and after the mixture of tetrazole compound and pyrimidine compound.The micro-topography and chemical composition of the adsorption film of inhibitor on steel surface are characterized by advanced analystic instruments. Also, using quantum chemical calculation and molecular dynamic simulation, it is to study the relationship between molecular structure and inhibitive ability, protonated effect of inhibitor, interaction effect between tetrazole compund and pyrimidine compound, and the adsorption behavior of inhibitor molecular on metal surface. It is attempted to propose the reasonable inhibitive mechanism. Then the synergistic mechanism is used to provide the scientific basis in search of highly effective composite corrosion inhibitors in acid solutions, and then lay the foundation of the exploitating the composite corrosion inhibitors using the mixture of tetrazole compounds and pyrimidine compounds.

缓蚀协同效应的研究与高效复配缓蚀剂的开发密切相关,一直是缓蚀剂研究领域的热点、重点和难点。本项目采用失重法、电化学法、金属表面仪器分析测试、量子化学计算及分子动力学模拟研究四氮唑类化合物和嘧啶类化合物对钢在酸溶液（无机酸和有机酸）中的缓蚀协同效应和机理。旨在筛选出四氮唑类化合物和嘧啶类化合物之间的系列缓蚀协同体系；积累缓蚀协同效应的重要新数据；揭示缓蚀剂复配浓度、温度、酸浓度、腐蚀时间、加剂顺序对缓蚀协同性能的影响规律；拟合缓蚀剂在钢表面的吸附等温式，得出吸附热力学和腐蚀动力学参数；结合电化学研究结果，阐明缓蚀剂复配前后的吸附行为和电化学作用机理；表征缓蚀剂吸附膜层的微观形貌和成分；阐释协同体系缓蚀剂分子的构效关系、质子化作用、相互作用及在钢表面的吸附行为；提出合理的缓蚀协同机理；为寻求钢在酸中高效复配有机缓蚀剂提供理论依据；为四氮唑类化合物/嘧啶类化合物复配缓蚀剂的开发奠定基础。

采用失重法、电化学法、金属表面仪器分析测试、量子化学及分子动力学模拟系统和深入研究了四氮唑类化合物和嘧啶类化合物对钢在酸中的缓蚀协同效应及机理，取得了预期成果：.1. 四氮唑类化合物对钢在酸溶液中的缓蚀性能研究：大部份四氮唑类化合物仍不能单独用作钢的缓蚀剂，而必须寻找其他嘧啶类化合物进行复配，使两者之间产生缓蚀协同作用。.2. 嘧啶类化合物对钢在酸溶液中的缓蚀性能研究：嘧啶类化合物的缓蚀率与嘧啶环上的取代官能团密切相关，缓蚀性能可大致排序为：—C6H5 > —SH > —Br > —NH2 > —OH > —Cl。.3. 四氮唑类化合物和嘧啶类化合物的缓蚀协同效应研究：建立了系列缓蚀协同效应体系：红四氮唑/脲嘧啶、5-巯基-1-四氮唑乙酸钠/5-碘尿嘧啶、5-氨基四氮唑/4,6-二羟基嘧啶、1-苯基-5-巯基四氮唑/2-氯嘧啶、1-甲基-5-巯基四氮唑/尿嘧啶等。.4. 四氮唑/嘧啶复配缓蚀剂在钢表面的物理化学吸附行为研究：四氮唑类化合物和嘧啶类化合物复配前后在钢/酸界面上的吸附一般服从Langmuir或Temkin吸附等温式；复配后具有更大的吸附平衡常数。.5. 四氮唑/嘧啶复配缓蚀剂的电化学机理研究：当四氮唑/嘧啶的复配缓蚀剂对钢在酸中的阴阳两极的腐蚀产生了显著地抑制作用；复配协同缓蚀剂的电荷转移电阻明显增大，而界面双电层电容下降。.6. 四氮唑/嘧啶复配缓蚀剂在钢表面吸附膜层的微观表征：四氮唑/嘧啶复配缓蚀剂添加后钢表面的腐蚀程度大幅度降低。复配后在钢表面吸附膜层中出现了C=N、C-N等特征吸收峰，且N1s的峰强度强于复配前的峰强度。.7. 四氮唑/嘧啶复配缓蚀剂的分子模拟研究：四氮唑/嘧啶缓蚀剂分子在钢表面的吸附方式为平躺式吸附，复配后的四氮唑/嘧啶缓蚀剂分子在钢表面的吸附能绝对值增加。. 项目执行期内，发表学术论文12篇，其中6篇被SCI收录；出版1部学术专著；申请国家发明专利2项（已授权）。项目负责人李向红晋升为教授，且入选 “云南省第十八批省中青年学术和技术带头人后备人才”，并担任中国腐蚀与防护学会缓蚀剂专业委员会委员。