Synthesis of some N-pyridinium salt derivatives as corrosion inhibitors for mild steel in sulfuric acid

This study involves the preparations of some pyridine derivatives starting from  Isonicotinic acid (1) following these steps :First : The Synthesis of  Isonicotinoyl acid chloride (2) by The  reaction of Isonicotinic acid (1) and thionylchloride .Second : The Synthesis of some amide and ester derivatives by reaction between  Isonicotinoyl acid chloride (2) and substituent amine or phenol derivatives ( Semicarbazide, Thiosemicarbazide, Benzohydrazide, Aniline, 4-phenylazoaniline, 4-phenylazophenol, p-Aminophenol, p-Aminoacetophenone, m-Toluidine, 4-Bromoaniline ) that yielded these compounds (A1-A10) .Third : The Synthesis of  some pyridinium salt derivatives by The  reaction of (A1-A10) and alkyl halides (ethyl chloroacetate,n-propyl bromide, benzyl chloride), that yielded these compounds (B1-B24) .All The prepared structure compounds were confirmed using spectroscopic techniques (FTIR & ¹HNMR). Prepared compounds (B1-B24) were successfully applied as organic corrosion inhibitors for mild steel in 1M H₂SO₄  solution at 30°C by using weight loss method after 24 hours immersion. The results of weight loss measurements showed that corrosion inhibition efficiency increased by increasing the concentration of organic inhibitors for mild steel in 1M H₂SO₄ solution at 30°C.