Preparation And Anti-corrosion Properties Of Polyaniline And Thiophenopyridine Corrosion Inhibitors

Mild steel has been widely used in many industries,attributed to its relatively low cost and high mechanical strength.It has been confirmed that the mild steel is highly susceptible to corrosion in acid media which are often encountered in oil well acidizing,acid clening and acid picking,which will induce safety and economic losses.Therefore,it is not only a technical problem to study the corrosion prevention of carbon steel in acidic media,but also a major strategic task related to environmental protection,energy and resources.Organic nitrogen-containing compounds are widely used in metal corrosion prevention due to their low toxicity,good adsorbability,good film-forming property and large coverage area.The research includes the following two aspects:1.Synthesis and Anticorrosion Properties of Thiophenepyridine Compounds.The diaminoethylthiophene compound is obtained with ethyl cyanoacetate and N,N-Dimethylformamide by Gewald Reaction,Knoevenagel condensation,cyclization and rearrangement with sulfur under alkaline conditions,the diaminoethylthiophene compound is obtained.Four thienopyridine compounds were synthesized by Friedl?nder reaction of diaminoethylthiophene compounds with a series of ketones under the reflux of POCl₃.The molecular structure was determined by a series of spectral performance tests.Then thienopyridine compounds were compounded with three surfactants to conduct electrochemical performance tests.The results show that thienopyridine compounds are mixed inhibitors,and the inhibition effect increases with the increase of inhibitor concentration.The corrosion process is mainly controlled by charge transfer,and the adsorption process consists of two parts,physical adsorption and chemical adsorption.The compound of cyclohexyl compounded with sodium dodecyl sulfate has the best corrosion inhibition effect,and the corrosion inhibition efficiency reaches 97.96%.2.Preparation and Anticorrosion Properties of Polyaniline & Polyaminophenol.A series of anti-corrosion nanomaterials were synthesized by using aniline?AN?and m-aminophenol?m AP?as monomers,acetic acid?Ac OH?and p-methoxyphenylacetic acid?MOPAc?as doped acids,Fenton(Fe²⁺/H₂O₂)reagent as initiator.The polymer was studied by spectrum,thermogravimetry and particle size distribution.The results showed that the polymer prepared by using p-methoxyphenylacetic acid as doped acid had uniform particle size distribution and good solubility.Thermogravimetric analysis shows that the mass loss of polyaniline is about 10% when heated to 350 ?,and the products with different doping formshave different heat resistance.Weightlessness method and thermodynamic analysis show that the adsorption of corrosion inhibitor on carbon steel surface follows Langmuir isothermal model and the reaction proceeds spontaneously.The adsorption process includes chemical and physical adsorption.Electrochemical tests suggested that the polymer was a cathode-based mixed corrosion inhibitor,MOPAc-Pm AP is the best corrosion inhibitor for polymer,MOPAc-Pm AP-Tween80 compounded with surfactant has the best corrosion inhibitor,and the corrosion inhibition efficiency reaches 96.05%.