Multicomponent Reactions, Solvent-Free Synthesis of 2-Amino-4-aryl-6-substituted Pyridine-3,5-dicarbonitrile Derivatives, and Corrosion Inhibitors Evaluation

Table 2

Corrosion rate, surface covering, and corrosion inhibition efficiency of 1, 5, 6, and 8 inhibitors at room temperature.

No.	Dose (ppm)	1 day			3 days			5 days			7 days			9 days
		K (mg·cm^−2h^−1)	θ	η (%)	K (mg·cm^−2h^−1)	θ	η (%)	K (mg·cm^−2h^−1)	(θ)	η (%)	K (mg·cm^−2h^−1)	θ	η (%)	K (mg·cm^−2h^−1)	θ	η (%)
	Blank	0.001590	—	—	0.001404	—	—	0.001484	—	—	0.00171	—	—	0.001968	—	—
1	200	0.001267	0.203	20.3	0.001029	0.2665	26.65	0.001046	0.2949	29.49	0.00116	0.3168	31.68	0.001202	0.3891	38.91
	400	0.001059	0.3337	33.37	0.000876	0.3755	37.55	0.000886	0.4027	40.27	0.000911	0.4673	46.73	0.000922	0.5316	53.16
	800	0.00090	0.4321	43.21	0.000750	0.4657	46.57	0.000732	0.5068	50.68	0.000705	0.5874	58.74	0.000704	0.6421	64.21
5	200	0.001057	0.3350	33.50	0.000832	0.4072	40.72	0.000842	0.4327	43.27	0.000873	0.4892	48.92	0.000850	0.5678	56.78
	400	0.001010	0.3642	36.42	0.000794	0.4341	43.41	0.000795	0.4642	46.42	0.000839	0.5089	50.89	0.000806	0.5902	59.02
	800	0.000832	0.4767	47.67	0.000617	0.5601	56.01	0.000607	0.5910	59.10	0.000582	0.6594	65.94	0.000569	0.7104	71.04
6	200	0.001148	0.2779	27.79	0.000983	0.2997	29.97	0.001000	0.3261	32.61	0.001100	0.3564	35.64	0.001097	0.4423	44.23
	400	0.001021	0.3576	35.76	0.000801	0.429	42.9	0.000793	0.4654	46.54	0.000895	0.4762	47.62	0.000911	0.5369	53.69
	800	0.000939	0.4092	40.92	0.000781	0.4432	44.32	0.000752	0.4929	49.29	0.000735	0.5697	56.97	0.000748	0.6199	61.99
8	200	0.001149	0.2772	27.72	0.000979	0.3021	30.21	0.001021	0.3120	31.20	0.001153	0.3254	32.54	0.001169	0.4060	40.60
	400	0.00104	0.3415	34.15	0.000800	0.4296	42.96	0.000776	0.4771	47.71	0.000846	0.5048	50.48	0.000871	0.5573	55.73
	800	0.000940	0.4083	40.83	0.000767	0.4532	45.32	0.000686	0.5374	53.74	0.000653	0.6181	61.81	0.000654	0.6675	66.74