Use of an amide-type corrosion inhibitor synthesized from the coffee bagasse oil on the corrosion of Cu in NaCl

Abstract

An amide, namely N-[2-[(2-hydroxyethyl) amino] ethyl]-amide, extracted from the fatty acids contained in the coffee bagasse, has been investigated as a possible green corrosion inhibitor for copper in 3.5% NaCl by using potentiodynamic polarization curves and electrochemical impedance spectroscopy measurements. Results were complemented by detailed scanning electronic microscopy, FTIR and gas chromatography studies. Results have shown that N-[2-[(2hydroxyethyl) amino] ethyl]-amide is a good, mixed type of corrosion inhibitor, with an efficiency that increases with its concentration but it decreases with a rise in the temperature. It adsorbs chemically onto the copper surface by following a Langmuir type of adsorption isotherm.

Use of an imidazol synthetized from palm oil as a corrosion inhibitor for a supermartensitic stainless steel in H2S

“…The passivation current density value in this case was 7 × 10 −4 mA/cm 2 , very similar to a typical passivation current density for this kind of steels in H 2 S-containing environments which is lower than 1 × 10 −3 mA/cm 2 (33)(34)(35). It has been established that the passive layer is formed of nickel, molybdenum, and in less amount chromium and iron sulfides (33,38,45) and it is the responsible for the decrease in the corrosion rate of the steel. When the inhibitor is added, the E corr value becomes nobler and the corrosion current density value decreases reaching its lowest value, 6 × 10 −6 mA/cm 2 , see Table 2, when 25 ppm of inhibitor are added, increasing again with a further increase in the inhibitor concentration.…”

“…The effect of inhibitor concentration on the polarization curves for the UNS S41425 type super martensitic stainless steel in the H 2 S-containing NaCl solution is given in Figure 5 whereas a typical cyclic polarization curve is given in Figure 6. It can be seen that in all cases, regardless of the inhibitor concentration, curves display an active-passive behavior as reported before (33,38,45).…”

“…Chemical analysis for both layers of corrosion products, Figure 12, indicates the presence of the elements present in the alloy, i.e. Fe, Cr, Ni, Mn, C and Si, together with some elements present in the solution such as S and Na, suggesting that maybe the main compounds should be sulfides and, probably some oxides as reported in earlier works (33,38,45); the presence of Mo in these corrosion products layer was not found, indicating, as suggested somewhere else (36)(37)(38) that it went directly into the solution. Some researchers have suggested that the Sulfide stress cracking and pitting resistance of supermartensitic stainless steels in sulfide environments is due to the formation of Mo sulfides on the external part of the corrosion products layer and that it can assist for the formation of a chromium oxide layer in the internal part of this layer (3,50,51).…”

“…The synthesis of Gemini surfactants from palm oil was performed in two steps as showed in Figure 1. First, the palm oil was transformed in fatty amide through the aminolysis direct of oil, as we reported previously (38). The mixture of fatty amides was washed with brine and the fatty solid was dried in vacuum.…”

How Strong is Hydrogen Bonding to Amide Nitrogen?

“…Despite the information abundance on the amide functionality, there is a continued interest in chemical synthesis, biosynthesis and reactivity of amides due to their importance in medicine, biology, chemistry and other related interdisciplinary sciences . This relevance encourages the research of the amide group's fundamental characteristics, e. g. the cis ‐ trans isomerization barrier, the resonance energy or acid‐base properties.…”