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Synthesis, Characterization and Hg(II) Ion Selectivity of 1‐(2‐Nitro‐4‐methyl phenyl)‐6‐methyl‐6‐methoxy‐1,4,5,6‐tetrahydro‐pyrimidine‐2‐(3 H ) thione (TPT)
Author(s) -
Jain A. K.,
Sondhi S. M.,
Sharma Vinay K.
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(20000301)12:4<301::aid-elan301>3.0.co;2-2
Subject(s) - potentiometric titration , chemistry , selectivity , sulfuric acid , membrane , inorganic chemistry , titration , nitro , nuclear chemistry , pyrimidine , ion , catalysis , organic chemistry , stereochemistry , alkyl , biochemistry
1‐(2‐Nitro‐4‐methyl phenyl)‐6‐methyl‐6‐methoxy‐1,4,5,6‐tetrahydro‐pyrimidine‐2‐(3H)thione (TPT) has been synthesized by the reaction of 4‐isothiocyanato‐butan‐2‐one with 4‐methyl‐2‐nitroaniline at reflux temperature in methanol using a catalytic amount of sulfuric acid (pH ca. 3). The TPT product was characterized by 1 H NMR, HRMS and IR. PVC‐based membranes of TPT were prepared and investigated for response towards Hg 2+ ions. Best performance was observed with the membrane containing 10, 200, and 200 mg of TPT, DOP (dioctylphthalate) and PVC, respectively. The membrane electrode works well over a wide concentration range 1.1×10 –5 –1.0×10 –1 M of Hg 2+ with a slope of 28.6 mV/decade of concentration of Hg 2+ . The useful pH range for the electrode was found to be 2.3–4.2 with a response time of 30 s. The selectivity coefficient values are of the order of 0.01 for mono‐, bi‐, and trivalent cations which indicate good selectivity for Hg 2+ ions over a large number of cations. The electrode has a lifetime of 3 months and could also be used as an indicator electrode in the potentiometric titration of Hg 2+ vs. EDTA.