Determination of the Ionization Constants of Some Benzoyl Thiourea Derivatives in Dioxane-Water Mixture

Table 2

Ionization constants (p𝐾_𝑎) determined by potentiometric method in 50% dioxane-50% water (v : v) mixture at 25.0±0.1°C (𝜇 = 0.10 M NaCl) of some benzoyl thiourea derivatives (𝜎_fit≤±0.03).

Group No	Sample No	Code	Compounds	BEST	𝑗−pH
I	1	4-H_Ph	N, N-diphenyl-𝑁^′-benzoylthiourea	9.23±0.06	9.23±0.08
	2	4-H_Et	N, N-diethyl-𝑁^′-benzoylthiourea	9.62±0.05	9.62±0.04
	3	4-H_Pr	N, N-di-n-propyl-𝑁^′-benzoylthiourea	9.80±0.04	9.79±0.09
	4	4-H_Bu	N, N-di-n-buthyl-𝑁^′-benzoylthiourea	9.84±0.06	9.84±0.06
II	5	4-Cl_Ph	N, N-diphenyl-𝑁^′-(4-chlorobenzoyl)thiourea	8.79±0.02	8.80±0.07
	6	4-Cl_Et	N, N-diethyl-𝑁^′-(4-chlorobenzoyl)thiourea	9.10±0.03	9.09±0.03
	7	4-Cl_Pr	N, N-di-n-propyl-𝑁^′-(4-chlorobenzoyl)thiourea	9.33±0.02	9.31±0.02
	8	4-Cl_Bu	N, N-di-n-buthyl-𝑁^′-(4-chlorobenzoyl)thiourea	9.39±0.01	9.37±0.01
III	9	4-Br_Ph	N, N-diphenyl-𝑁^′-(4-bromobenzoyl)thiourea	8.91±0.02	8.93±0.04
	10	4-Br_Et	N, N-diethyl-𝑁^′-(4-bromobenzoyl)thiourea	9.09±0.01	9.08±0.01
	11	4-Br_Pr	N, N-di-n-propyl-𝑁^′-(4-bromobenzoyl)thiourea	9.24±0.01	9.23±0.01
	12	4-Br_Bu	N, N-di-n-buthyl-𝑁^′-(4-bromobenzoyl)thiourea	9.31±0.01	9.30±0.01