Synthesis Of Dodecane Alkyl Metronidazole Bisquats And Its Speciality Against Microbe Induced Corrosion

In this paper, two new germicide-inhibitor of bisquats which were named N-Metronidazole-N-( Dodecane Dimethyl )-3-Oxa -1,5-Pentanedilammonium Dichloride ( MDOPD ) and N-Metronidazole-N-( Dodecane Dimethyl )-2-Hydroxy-1,3-Thirddilammonium Dichloride ( MDHTD ) were successfully synthesized for the first time with metronidazole as matrix and 2,2-Dichloroethyl ether 1-Chloro-2-2(β-chloroethoxy) ethane or α-epichlorohydrin as link agent, respectively. The molecule structures of bisquats were illustrated by IR spectrum and the synthesis conditions were optimized in detail such as solvent, temperature and reaction time. Weight loss measurement, Potentiodynamic polarization curves, Electrochemical Impedance Spectroscopy (EIS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to investigate the corrosion inhibiting performance of MDOPD and MDHTD in simulated oilfield water. MDOPD and MDHTD were found to having good water solubility and prominent corrosion inhibiting performance, temperature had little effect on inhibitory efficiency of MDOPD and MDHTD in the studied temperature range at higher inhibitor concentrations. The corrosion mechanism of carbon steel in simulated oilfield water containing MDOPD or MDHTD was analysed with thermodynamic and kinetics models, MDHTD and MDOPD possessed several nitrogen atoms as adsorption centre which had much active energy with metal surface and MDHTD had more effectively protection function. The anode reaction of corrosion course was restrained on account of the addition of MDHTD in culture medium inoculated SRB, phenomenon of maximum concentration effect was found while concentration of MDHTD was increased. The anode polarization curves revealed three different segments and temparature had little effect on the adsorption of MDHTD on Q235 steel. Corrosion of Q235 steels in culture medium inoculated SRB was effectively restrained by the sterilization capability of MDHTD against SRB in medium and the adsorption on Q235 steel surface. And that MDHTD had more excellent protective effect than 1227 in culture medium inoculated original SRB or drug-fast SRB. The sterilization effect of the bisquats was assessed according to API RP-38 standard. MDHTD exhibited better inhibitive effect on drug-fast SRB and original bacteria not only in culture medium but also in biofilm. Besides, the two bactericides also showed excellent inhibitive performance against IB at low concentration. The inactivation curves indicate that MDHTD has more effective antibacterial performance than "1227"due to the functional group in molecule structure of MDHTD. At the same time, MDHTD has effect on the formation and growth of TGB biofilm and some TGB has distinct sensitivity to MDHTD. Sensitivity of SRB biofilms to MDHTD and corrosion inhibiting effect of MDHTD for metal under biofilms were further investigated using Atomic Force Microscopy (AFM),Electron Probe Micro-Analysis (EPMA) ,X-ray Photoelectron Spectroscopy (XPS) and EIS. Results revealed that MDHTD had better protective effect than "1227"on Q235,J55,N80 steel in culture medium inoculated SRB by forming adsorption film segregating chlorine ion on metal surface and corrosion under various thickness biofilm was also effectively restrained by MDHTD. Metabolite and FeSx by SRB greatly decreased owing to impact of MDHTD. The binding force between metal surface and biofilm was reduced by peeling off effect of MDHTD and charge transfer resistance of corrosion reaction accordingly increased, so corrosion induced by corrosive chlorine ion penetrating the porous biofilm was commendably restrained. AFM,EPMA and EIS were initially used to research the mechanism of MDHTD against TGB in culture medium. Results showed that MDHTD could form integrated and compact adsorption film on Q235 steel in culture medium, it was difficult for metabolite by TGB to deposit on the carbon steel surface and phosphorus was enriched on biofilm surface. Furthermore, corrosion caused by oxygen concentration difference was effectively inhibitted by penetration, peeling off and adsorption effect of MDHTD. In a word, Microbiologically Influenced Corrosion in oilfield system could be restrained by addition o f MDHTD on account of its action on the self-existent activation effect by microbe.