Corrosion Inhibition of Mild Steel in Acidic Media by 5′-Phenyl-2′,4′-dihydrospiro[indole-3,3′-pyrazol]-2(1H)-one

Table 2

Inhibition efficiencies of inhibitor for the corrosion of mild steel obtained by weight loss measurements at various temperatures.

Concentration of the inhibitor (ppm)	Temperature (K)	1 M HCl		0.5 M H2SO4
		Corrosion rate (mpy)	Inhibition efficiency (%)	Corrosion rate (mpy)	Inhibition efficiency (%)
	303	930	32.7	887	43.5
	313	1927	29.4	1151	37.2
1	323	2294	27.1	5756	28.6
	333	5211	16.0	9858	20.3
	343	10353	12.2	18019	15.0
	303	759	54.1	733	53.3
	313	1595	41.6	785	50.0
3	323	1902	39.6	3795	48.9
	333	4375	28.8	7411	40.1
	343	9611	18.5	14975	29.4
	303	623	54.9	452	71.2
	313	1296	52.5	631	65.6
5	323	1535	51.2	3087	58.4
	333	3411	45.0	5876	52.5
	343	8613	27.0	13380	36.9
	303	529	61.7	409	73.9
	313	1117	59.1	588	67.9
7	323	1441	54.2	2695	63.7
	333	2857	50.5	5475	55.7
	343	7334	37.8	12502	41.1
	303	461	66.7	341	78.3
	313	1015	62.8	452	75.3
9	323	1237	60.7	2072	72.1
	333	2499	59.7	4827	61.0
	343	5543	53.0	10114	52.3