PIPERINE EXTRACTED FROM BLACK PEPPER ANOTHER PROPRIATE GREEN INHIBITOR AGAINST THE CORROSION OF METALS

Piperine is the natural alkaloid occurring in black pepper that gives the spice, its characteristic biting taste. Piperine is easily extracted from black pepper and is the main ingredient among the others as: piperidine and piperettine. It is medicinally used as anti-inflammatory, anti- malarial, cure for stomach ache, weight loss, anti-leukemia etc. Recent studies have shown, that piperine is an efficient inhibitor against the corrosion of metals.This represent a great interest, because most of synthetic compounds that have good anticorrosive activity, are highly toxic to both, human beings and environmental. So the compounds extracted from plants, named green inhibitors, are cheap and safety handled to be used as corrosion inhibitors. The extract of piperine from black pepper, represent a great inhibitive action, against the corrosion of metals and alloys in acidic media. Piperine from black pepper was obtained by water extraction with water bath in 100oC and with ethanol (95%) in a Soxhlet apparatus. The extract was stored at 4oC and in the dark, to avoid the oxidation.The product of extraction was analyzed with infrared (IR) and ultraviolet (UV) spectroscopy, in order to define its chemical structure. Also we defined the yield, density, melting point and molecular weight of the product. The product of extraction was piperine. The corrosion inhibition efficiency was investigated using weight loss method. Different concentrations of inhibitor were used and an increase of efficiency was observed with the increase of the concentration. So, IE = 80%, for concentraction1.0g/l.