Copper ethanolamine complexes

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. 

Dairy phospholipids are important structurally, because they are able to stabilise emulsions and foams, and to form micelles and membranes (Jensen and Newburg, 1995). Phospholipids also have the potential to be pro-oxidants, because they contain mono-unsaturated and poly-unsaturated fatty acids and have the ability to attract metal ions. Phosphatidyl ethanolamine binds copper strongly and is believed to be important in copper-induced oxidation in milk (O Connor and O Brien 1995 Deeth, 1997). The polyunsaturated fatty acids and metal ions accelerate lipid oxidation, especially when heat is applied hence, phospholipids can be degraded during the processing of milk. However, in dairy products, the situation is complex and it appears that phospholipids are able to act as either pro-oxidants or antioxidants, depending on the pH, ratio of water and phospholipid species (Chen and Nawar, 1991). 

Oxazolidines (53) are readily formed from aldehydes or ketones and ethanolamines they can be hydrolyzed with ease and show reactions that might be expected of the imino alcohol intermediate (54). Among these are the addition of Grignard reagentsand catalytic hydrogenolysis of the C—O Ixjnd (equation 28).This reaction is exothermic over Adam s catalyst in methanol but slower in acetic acid. Nickel and copper chromite are also effective but at higher temperatures and pressures,as is the case with palladium. The same cleavage occurs with LAH (unassisted)and with the borane-THF complex. ... 

Not only complexes but also metal salts that complex with the compounds to be separated can be used as selective complexing stationary phases. For example, Phillips [91] described the use of zinc and copper stearates and nickel oleate for the selective separation of amines. The retentions of aliphatic amines decrease in the order primary > secondary > tertiary. The separation of 7-picoline and 2,6-lutidine on a zinc stearate column is possible if the column efficiency is only 4 theoretical plates and the column is 1 cm long. To effect this separation on a non-selective silicone stationary phase a column with an efficiency of 250,000 theoretical plates is required. Some amines (e.g., ethanolamine... 

Chemical complexation already has become well established as a separation method in analytical chemistry and on a large scale in the applications of gas absorption and metals extraction. The ethanolamine and carbonate systems for removal of CO2 and H]S from gas streams are classic examples of complexation. Practical aspects of these systems are discussed in Chapter 6 and by Kohl and Riesenfeld, and the more theoretical aspects are discussed by Danckwerts, Danckwerts and Sharma, and Astarita et ai. In the metals industry, complexation is used extensively in the hydrometallurgical production of copper and uranium and in the refining of nickel, molybdenum, cobalt, and other metals for examples see Chapter 8 or the Proceedings of the triennial International Conferences on Solvent Extraction. 

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