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Morpholine was the most eVective amine and caprylic acid the most eVective acid constituent. T he eVectiveness of ammonium monocarboxylates decreased with increase in the length of the carbon chain of the carboxylic acid. T he other carboxylates did not show such a clear trend.

Proprietary mixtures of amines and carboxylic acids are used as volatile corrosion inhibitors (VCIs) for the protection of iron and steel components against atmospheric corrosion. This study was focused on the nature of the vapors they release. VCI model compounds comprising mixtures of triethylamine and acetic acid were studied using thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TGA-FTIR) at 50°C. As vaporization progressed, the composition of the remaining liquid and the emitted vapor con v erged to a f i xed ami ne con ten t of ca. 27 m ol e percen t. Thi s was j ust ab ov e th e composition expected for the 1:3 amine to carboxylic acid complex. Mixtures close to this composition also featured the lowest volatility.

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For a compound to be classified as a volatile corrosion inhibitor (VCI), it must possess two basic properties: volatility and ability of the vapour to retard the corrosion rate. VCIs can be used in cases where other protection methods are not feasible or when protection could be very expensive. Usually, most organic compounds giving inhibitive action against corrosion of metals have one or more electronegative atoms (e. g. oxygen, nitrogen, sulphur) in the form of functional groups and/or have an unsaturated bond. Inhibitors for atmospheric corrosion can be used economically only in enclosed spaces. When metal items are in transit, the following protection methods should be considered: protective oils, water or oil based formulations and/or protective packaging. In the manufacture and use of corrosion inhibitors and their products (e.g.VCI paper), workers are occupationally exposed to various chemicals, noise and elevated air temperatures. The concentrations of chemicals in workplace air are dependent on the manufacturing process and equipment used. It is recommended that any plant processing VCIs should have good processing equipment and ventilation. Workers should wear protective clothing, safety glasses and gloves when handling VCI products.