Synthesis Of Novel Water-soluble Iron Phalocyanine And Its Application In Chlorophenol Detection

Phenols and their derivates (such as chlorophenols) are common environmentalpollutants generated from industrial manufacturing processes of pesticide, fungicide,chemical dye and polymer, and so on. Contamination by these phenolic chemicals isthe most serious problem for their high toxicity, non-biodegradation, and heavydiffusibility in water environment. Therefore, the fast and efficient identification ofphenolic pollutants is of important significance to environment protection andhuman health. As the fiber optic sensors have many advantages such as a highlysensitive detection, immunity from electrical interference and can be used for onlineand real-time monitoring, it has been regarded as an efficient method to detectphenolic chemicals, and the study has great theoretical significance and applicationvalue.Metal phthalocyanine (MPc) is a kind of mimic enzyme with the planarring-conjugated complex. Due to its excellent performance of biomimetic catalysisand good stability, MPcs became the artificial catalysts to replace natural enzymesand were used as the sensing materials of fiber optic chemical sensors. But the lowwater-solubility and easy aggregation are the main reason of low catalytic efficiency.In this paper, the FePc complexes with sterically hindered groups on Pc ring wassynthesized. Because of the good water-solubility and high catalytic efficiency of theMPc catalysis, it was promising for the application in fiber sensor for betteridentification of phenolic pollutants.The novel water soluble and sterically hindered phthalocyanine complexe, tetra(4-carboxyphenoxy) iron (III) phthalocyanine (FePc(PhCOOH)4) was synthesized.The FePc complexe exhibited the high catalytic activity in the chromogenic reactionsof phenolic pollutants. Five phenolic substrates, including phenol,2-chlorophenol(2-CP),4-chlorophenol(4-CP),2,4-dichlorophenol(DCP) and1-naphthol(1-NP) could be efficiently oxidized by tert-butyl hydroperoxide(t-BuOOH) in the presence of this FePc catalyst. The catalytic oxidation rate forthese five substrates follows the trend: DCP>2-CP> phenol>4-CP>1-NP;The system of FePc catalyzed2-CP reaction was studied, and our experimental measurement indicated the chromogenic process of2-chlorophenol could becompleted just within10min with93%of conversion. Moreover, the experimentalconditions (such as concentration of t-BuOOH and4-AAP, pH and temperature) forFePc catalyzed chromogenic reaction were optimized for the purpose of fastchromogenic identification of phenolic pollutants;The fiber optic2-CP sensor based on2-CP oxidation catalyzed byFePc(PhCOOH)4was developed. The2-CP concentration can be determined byutilizing a lock-in amplifier to measure the phase delay (that is, fluorescence lifetime)of an oxygen-sensitive membrane;The sensor has the good linear relationship between the phase delay of sensitivemembrane and2-CP concentration in its detection range of1×10-7to1×10-5mol/Land1×10-5to1×10-4mol/L. The detection limit of the sensor is7×10-8mol/L (S/N=3)and the response time is5min. Our experimental measurements have confirmedgood response characteristics of the as-prepared fiber optic2-CP sensor, as well asits capability to detect the2-CP concentration in practical water samples.