QSAR Study And Molecular Design Of Benzimidazole Derivatives As Corrosion Inhibitors

In the process of oil and gas exploration and production, the oil and gas wells andequipments usually be treated by acidification or pickling, but the acid solution has seriouscorrosion function on the mining equipments, transmission pipelines and storage tanks. Tosolve this problem, reasonable adding corrosion inhibitors into the environment media isregarded as an effective measure in the actual operation process. At present, the acidiccorrosion inhibitors have limited kinds and are very expensive, while the traditional researchand development strategies of corrosion inhibitor have long work cycle, great blindness andrandomness. To overcome the shortcomings of traditional methods, this thesis will use thethought of computer aided molecular design, introduce the Three-Dimensional QuantitativeStructure-Activity Relationship (3D-QSAR) and Hologram Quantitative Structure-ActivityRelationship (HQSAR) into corrosion inhibitor field to carry out the design of new corrosioninhibitors. The systemic research results are as follows:In the Three-Dimensional Quantitative Structure-Activity Relationship (3D-QSAR)analyses,15kinds of benzimidazole derivatives as corrosion inhibitors in hydrochloric acidwere studied using Comparative Molecular Field Analysis (CoMFA) and ComparativeMolecular Similarity Indices Analysis (CoMSIA) methods, and the stability and predictiveability of the3D-QSAR model were examined by leave-one-out (LOO) cross-validationmethod. The model results show, CoMFA (q2=0.541，r2=0.996) and CoMSIA (q2=0.581，r2=0.987) models had good statistical stability and predictive ability; contour maps of bothCoMFA and CoMSIA model can well explain the reason for the difference of molecularactivity; the steric, electrostatic and hydrogen-bond donor fields were main factors toinhibition performance. By analyzing the CoMFA contour map for each molecule in thetraining set, molecule12was selected to be modified, and14new benzimidazole molecules with higher corrosion inhibition properties were designed.In the Hologram Quantitative Structure-Activity Relationship (HQSAR) analyses, theHQSAR model between corrosion inhibition properties and molecular structures were built onbenzimidazole compounds, the optimal HQSAR model was determined by investigating theinfluence of different fragment distinctions and fragment sizes on the models, and the models’stability and predictive ability were evaluated. The results show that the optimal HQSARmodel was generated using atoms(A), bonds(B), connectivity(C), hydrogen(C), chirality(Ch),donor and acceptor(D&A) as fragment distinction and fragment sizes of1~3. The model had aconventional r2value of0.996, a cross-validated q2value of0.960, and a standard error SEvalue of3.709, which indicates good statistics stability and predictive power. On the basis ofthe maps derived from the optimal HQSAR model,38new benzimidazole derivatives weredesigned and screened using the optimal HQSAR model, giving potential candidates withhigh predictive inhibition efficiency.These results suggested that it was available to introduce3D-QSAR and HQSARmethods into the field of corrosion inhibitor, and the method provided a new train of thoughtfor the research and development of corrosion inhibitor in the oil and gas field.