Inhibition of Cu

Warshawsky, A., Rogachev, I., Patil, Y., Baszkin, A., Weiner, L. and Gressel, J. (2001). Copper-specific chelators as synergists to herbicides 1. Amphiphilic dithiocarbamates, synthesis, transport through lipid bilayers, and inhibition of Cu/Zn superoxide dismutase activity, Langmuir, 17, 5621-5635. 

Amino-1,2,4-dithiazole-5-thione may be used for corrosion inhibition of Cu-)-Zn powder mixture <86Mi 413-03) or for inhibition of polymer ageing <85URPl 142485) A-alkoxy derivatives inhibit corrosion of iron <91URP1650683,82MI413-06,82MI413-07). 1,2,4-Dithiazolidines (247 = H,... 

Polticelli F. Battistoni A. O Neill P. RotilioG. Desideri A. Identification of the residues responsible for the alkaline inhibition of Cu, Zn superoxide dismutase a site-directed mutagenesis approach. Protein Sci. 1996, 5, 248-253. 

The models are extended from Pt/TiOg to some other systems for which data are available. The Inhibition of Cu/Zn0/Al203 methanol synthesis catalysts by low levels of Group VIII metals, especially cobalt, Is shown to fit the same pattern of SMSI the active metal... 

Marrubium vulgare Antioxidant Inhibition of Cu (2+)- and AAPFI induced LDL oxidation [20]... 

Hydroxy quinoline Cu XPS, FTIR, and SEM stated that protective film is formed on surface by polymerization of Cu(II) - hydroxy quinoline complexes, films that play essential role in inhibition of Cu corrosion 1061... 

Fleischmann et al [22] compared benzotriazole and 2-mercaptobenzoxazole as inhibitors of copper corrosion in KCl solutions containing low concentrations of cyanide. Benzotriazole proved to be an ineffective inhibitor in cyanide media, while 2-mercaptobenzoxazole remained effective. SERS showed that cyanide, revealed by a broad band centred at 2090 cm displaced benzotriazole from the Cu surface, whereas 2-mercaptobenzoxazole displaced adsorbed cyanide. A synergetic inhibition of Cu corrosion by benzotriazole and benzylamine, both in chloride and chloride/cyanide media, was also shown [22]. As SERS showed that benzylamine had not been adsorbed, its beneficial effect was ascribed to an improved film formation. Subsequent 4or measurements showed that benzotriazole, MBO, 2-mercaptobenzothiazole and 2-mercaptobenzimidazole were all effective inhibitors of copper corrosion in neutral chloride solutions, but the inhibition efficiency of benzotriazole was decreased at pH 1-2 [23]. SERS spectra showed that, at pH 7, benzotriazole and its anionic form were coadsorbed and Cl was excluded from the interface. However, at pH < 2 undissociated benzotriazole and CH were coadsorbed, such that Cu underwent corrosion. In contrast, the anion from 2-mercaptobenzothiazole was the only adsorbed species at pH between 7 and 2 only at pH 1 was the neutral 2-mercaptobenzothiazole molecule detected. Competitive adsorption experiments showed that the inhibitive action of benzotriazole and 2-mercaptobenzothiazole in neutral/acid media could be explained in terms of adsorption strength. 

The effect of gluconate varies with the electrode potential. When the cathodic polarization is sufficiently low E > -0.4 V), a weak inhibition of Cu(II) reduction is observed with increasing (Figure 9.16). Similar and stronger effects were also observed in the case of simple Cu(II) gluconate solutions at lower pH. For instance, gluconate gives rise to the substantial increase in cathodic polarization... 

Halides exert an essential influence on the adsorption of polyethers. It is particularly remarkable that this effect is quite different for copper and tin electrodes. Significant enhancement of adsorption resulting in the inhibition of Cu(II) reduction is observed in the Cu Cu(II) system, whereas diminished polymer adsorption was found to occur in the case of tin electrode. This can be seen from the example shown in Figure 9.29. In the case of copper system, Nyquist plots take the shape of arcs centered below the abscissa axis. An addition of Cl ions gives rise to a decrease in impedance as compared to that obtained for halide-free solution (dashed lines in Figure 9.29). This result is in accordance with voltammetric data [75] chloride diminishes the polarization of Cu(II) reduction. However, the rest halides (Br and I ) increase the impedance over an entire range of the frequencies applied. An opposite effect can be seen in the case of tin system (lower part of Figure 9.29). Both enhancement and suppression effects intensify in the sequence Cl < Br" < I . 

Formation of SAMs on Cu substrates has attracted attention for both fundamental and apphed research, e.g. corrosion inhibition " of Cu used in microelectronic device fabrication. Cu is destined to replace A1 alloy as the principal very-large... 

Admiralty Brass and Naval Brass are 30 and 40% zinc alloys, respectively, to which a 1% tin addition has been added. Resistance to dezincification of Cu—Zn alloys is increased by tin additions. Therefore, these alloys are important for thein corrosion resistance in condenser tube appHcations. In these, as weU as the other higher zinc compositions, it is common to use other alloying additives to enhance corrosion resistance. In particular, a small amount (0.02—0.10 wt %) of arsenic (C443), antimony (C444), or phosphoms (C445) is added to control dezincification. When any of these elements are used, the alloy is referred as being "inhibited." For good stress corrosion resistance, it is recommended that these alloys be used in the fiiUy annealed condition or in the cold worked plus stress reHef annealed condition. 

As was noted by Jones (ref. 12) the success of a metal bromide as a catalyst for alkylaromatic autoxidations depends on the ability of the metal to transfer rapidly and efficiently oxidizing power from various autoxidation intermediates onto bromide ion in a manner which generates Br-. The fact that no free bromine is observable in this system is consistent with rapid reaction of intermediate bromine atoms with the substrate. Inhibition of the reaction by cupric salts can be explained by the rapid removal of Br2 or ArCH2- via one-electron oxidation by Cu (Fig. 10). 

Poisoning of deNOx catalysts by SO2 could also be a problem since diesel fuels contain small amounts of sulfur compounds. Only a few studies deal with this subject [11-13]. It appears from the literature that for Cu catalysts the use of MFI as a support reduces the inhibition by SO2. Support effects also appear in the case of Co since Co/MFI is much less sensitive to SO2 than Co/ferrierite [13]. Since this support effect may be related to acidity, it becomes important, to investigate the influence of SO2 on the properties of Cu catalysts supported on Si02, AI2O3, MFI, BEA and unpromoted or sulfate promot Ti02 and Zr02- These latter have been reported active for deNOx [14]. 

In conclusion, Cu on Ti02 or Zr02 show a unique and interesting behaviour since their deNOx activity is promoted and not inhibited by the presence of sulfur in the feed. This effect can hardly be attributed to a selective inhibition of the oxidation of decane, and is better explained by the promotion of a bifunctional mechanism involving the acid sites created on the support by the reaction of SO2. 

Chen, Z. and L.M. Mayer. 1998. Digestive proteases of the lugworm (Arenicola marina) inhibited by Cu from contaminated sediments. Environ. Toxicol. Chem. 17 433-438. 

The composite effect of Cl- was interpreted by assuming that the formation of Cu(I) intermediates is enhanced via the [Cu2AC12] complex. However, the relative concentration of this species decreases with increasing [Cl-] because of the formation of the [Cu2AC14]2- complex, and ultimately this leads to chloride ion inhibition at higher concentrations of Cl-. 

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