Copper azole

Copper azole is another recently developed water-based preservative formulation that relies primarily on copper solubilized in ethanolamine and an organic trizaole co-biocide. The first copper azole formulation developed contained 49% copper, 49% boric acid, and 2% tebuconazole. More recently, a formulation containing 96% copper and 4% tebuconazole has been used. As with ACQ formulations the copper in copper azole systems provides the primary fungicide and insecticide activity. The azole component provides protection against copper tolerant fungi. 

Copper azole has gained widespread use in Europe, North America, Australia and New Zealand. 

The shift to preservatives based on copper, azoles, and quaternary ammonium compounds has lessened the risk associated with wood preservatives. However, all wood preservatives contain ingredients that pose some degree of risk to non-target organisms, and the public and regulatory perception of a proper balance between risk and benefit is steadily changing (Brooks, 2002 Lebow et al., 2002). Preservative ingredients that are considered acceptable today may be considered as less desirable in the future. 

The voluntary withdrawal of chromated copper arsenate (CCA) as a wood preservative for domestic applications was driven by public concerns over its health and environmental profile. In its place have risen two competing systems, the amine copper quat (ACQ) system and the copper azole system. Both systems avoid using heavy metals such as chromium and arsenic and rely on the co-biocidal effects of copper and organic biocides. The elimination of CCA has created many opportunities for oleochemicals as preservative companies try to develop formulations that are not only environmentally friendly but can also match the preservative performance of CCA [66]. The ACQ system is based on didecyldimethyl ammonium bicarbonate and has produced a significant demand for ClO-based amine and quat. The azole systems use biocides such as tebuconazole and propiconazole in combination with copper ethanolamine complexes. Ethoxylated amines [67] and amine oxides [68] have been described as providing improved performance in azole-based systems. Other copper systems have employed ethoxylated diamines [69] and amine oxides [70] to enhance performance. 

Copper corrosion inhibitor None Benzotri azole/ toyltriazole Benzotriazole/ toyltriazole None Benzotriazole/ toyltriazole Benzotriazole/ toyltriazole... 

Pinacolone, o-(diphenylphosphino)benzoyl-coordination chemistry, 2, 401 Ping-pong reactions copper(II) complexes, 5, 717 Piperidine, /V-hydroxy-metal complexes, 2, 797 P a values azole ligands, 2, 77 Plant roots amino acids, 2, 962 carboxylic adds, 2,962 Plants... 

Model systems for Type I copper proteins structures of copper coordination compounds with thioether and azole-containing ligands.17... 

Inhibition of Copper Corrosion by Azole Compounds in Acidic Aqueous Solutions... 

Azole compounds, poly-N-vinylimidazole (PVI-1) and 2-undecylimidazole (UDI), are studied as alternative inhibitors to benzotriazole (BTA) for copper corrosion in aqueous systems using electrochemical techniques. It is shown that UDI, either as a cast film or dissolved in solution at concentrations as low as 7 X inhibits oxygen reduction on... 

Azole compounds such as benzotriazole, benzimidazole, indazole and imidazoles are efficient anti-corrosion agents for copper and copper-base alloys [1-10]. Many experimental techniques [11-15] have been used to study the corrosion inhibition mechanisms, however, the mechanisms are still not well understood. It is believed that the complex formation between copper and nitrogen atoms would inhibit oxygen adsorption on copper surface [16-20]. 

The ditetrazolium salts (309) have been patented for use in electrochromic electrodes which are used in display devices <89JAP01230026) and tetrazolium salts have also been developed for cell bioassays for neurotoxins active on voltage-sensitive sodium channels <93MI 417-03). Tests for inhibition of corrosion of zinc and brass carried out on 5-aminotetrazole showed it to be ineffective relative to other azoles <86MI 417-01). A number of tetrazoles including the 5-amino, 5-methyl, and 5-phenyl derivatives have been separately incorporated into surfactants used for corrosion inhibition with copper in water <9lMl4l7-07). Photopolymerizable resin compositions which are highly resistant... 

Under copper catalyzed conditions azoles (i.e. imidazoles) couple not only with aryl halides but also with arylboronic acids. The reaction, run in the presence of oxygen, follows a unique path (for details see Chapter 2.5.). From the synthetic point of view, the arylation of imidazole proceeds in good yield, although the regioselectivity in the arylation of 4-substituted imidazoles is only moderate (6.70.),102... 

In certain cases copper catalyzed processes might also be used for the N-alkynylation of azoles. Methyl indole-3-carboxylate was coupled with 1-bromo-2-triisopropylsilyl-acetylene in the presence of a copper-phenantroline catalyst to give the desired 1-ethynylindole derivative in excellent yield (6.74.),105... 

The selective arylation of azoles, including imidazole, was achieved by Sames. Under the developed conditions, including the use of magnesium oxide as base, imidazole was arylated in the 4-position selectively, while the addition of a stoichiometric amount of copper(I) iodide led to the reversal of the regiochemistry, resulting in the selective formation of 2-phenylimidazole (6.89.),120... 

Aromatic azoles are specific corrosion inhibitors for copper. They also show promise for acting synergistically with other inhibitors to lower corrosion rates on mild steel. One of the more cost effective aromatic azole inhibitors is tolytriazole (TTA). It and other azoles, however, are, subject to degradation in environments containing chlorine (Roti 1985). Azoles can also be quite dangerous to human health, and must be used with care. 

The resulting triazoles can be N-alkylated by treatment with alkyl halides (0.25 mol/L, 30 equiv., DMF, NaOH), but mixtures of the 1-alkylated and 2-alkylated triazoles are obtained [255]. 1,2,4-Triazoles have also been prepared from N-amino-amidines (amidohydrazones Entry 4, Table 15.20), which were prepared from resin-bound thioamides by S-alkylation with methyl triflate followed by treatment with hydrazine [256]. 1,2,4-Tri azoles undergo Michael addition to polystyrene-bound a-acetamido acrylates to yield triazole-derived a-amino acids (Entry 7, Table 15.20). Benzotriazoles have been N-arylated on insoluble supports by treatment with aryl-boronic acids in the presence of catalytic amounts of copper salts (Entry 8, Table... 

Various aromatic azoles have been used in cooling water formulations as specific inhibitors for copper and copper alloys, where they are chemisorbed onto the metal surface. 

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