经硫脲改性后的酸化缓蚀剂的研究

Research on Thiourea Modified Acidizing Corrosion Inhibitor

以硫脲、肉桂醛和苯乙酮为原料合成一种曼尼希碱酸化缓蚀剂,通过正交试验优化得到的合成条件:n(醛)∶n(胺)=1.6,n(酮)∶n(胺)=1,体系p H为4,反应时间为8 h,反应温度为60℃。用失重法和电化学方法评价了曼尼希碱在不同温度及不同浓度盐酸下的缓蚀性能。在15%盐酸中,当缓蚀剂加量为1.0%时,N80钢片的腐蚀速率为0.408 2 g/(m2·h),低于SY/T5405—1996《酸化用缓蚀剂性能试验方法及评价指标》中的一级标准。缓蚀剂在钢铁表面的吸附符合Langmuir吸附等温方程。由Tafel曲线可知,该缓蚀剂是以抑制阳极腐蚀过程为主的混合型缓蚀剂。交流阻抗分析表明其Nyquist图是处于第一象限的半圆,缓蚀剂浓度越大,容抗弧越大,缓蚀效果越好。

A Mannich base acidizing corrosion inhibitor was synthesized with thiourea, cinnamic aldehyde and acetophenone as the materials, and the synthesis conditions were identified by the optimization through orthog- onal test： n （ cinnamic aldehyde） ： n （amine） = 1.6, n （acetophenone） ： n （amine） = 1, the pH value of the system is 4, the reaction time is 8 h, and the reaction temperature is 60℃. Weight loss method and electro- chemical method were used to evaluate the corrosion inhibition performance of Mannich base at different temperatures and when different concentrations of hydrochloric acid were adopted. In the case of 15% concentration of hydrochloric acid, the corrosion rate of N80 steel sheet is 0. 408 2 g/（ m2·h） when the corrosion inhibitor addition is 1.0%, which is lower than the corrosion rate for the first grade corrosion inhibi- tors as specified in SY/T 5405 - 1996＂ Performance Test Methods and Evaluation Indicators of Corrosion Inhibitors for Acidification＂. The adsorption of the corrosion inhibitor to the surface of steel accords with Lang- muir adsorption isotherm equation. It can be seen from Tafel curve that this corrosion inhibitor is a mixed corrosion inhibitor that inhibits anodic corrosion for the most part. According to the results of AC impedance analysis, the Nyquist chart of this corrosion inhibitor is a semi circle in the first quadrant which shows that the larger the concentration of corrosion inhibitor is, the larger the capacitive loop is, and the better the corrosion inhibition effect is.