Phthalates degradation products

Exposure. Methods for Determining Parent Compounds and Degradation Products in Environmental Media.Methods are available for measuring di-tt-octylphthalate and/or its metabolites (primarily the corresponding phthalate monoesters) in urine, blood, and tissues (Albro and Moore 1974 Lanina et al. 

Biological. o-Phthalic acid was tentatively identified as the major degradation product of di-.n-octyl phthalate produced by the bacterium Serratia marcescens (Mathur and Rouatt, 1975). When di-.n-octyl phthalate was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, no degradation was observed after 7 d. In a 21-d period, however, gradual adaptation did occur, resulting in 94 and 93% losses at concentrations of 5 and 10 mg/L, respectively (Tabak et ah, 1981). In the presence of suspended natural populations from unpolluted aquatic systems, the second-order microbial transformation rate constant determined in the laboratory was reported to be 3.7 + 0.6 x lO L/organism-h (Steen, 1991). 

Phthalates are easily released into the environment because there is no covalent bond between them and plastics in which they are mixed. The major portion of phthalates that are found in the environment comes from the slow releases of phthalates from plastics and other phthalate containing articles due to weathering. At natural conditions, phthalates are hydrolyzed to some extent yielding their corresponding monoesters, which are also environmental pollutants [15]. They show poor mobility in soil but aqueous leachates from landfills may contain trace amounts of more soluble products of phthalate degradation [11, 16]. 

Duloxetine hydrochloride, a novel anti-depressive, is known to be acid labile and, consequently, it has been formulated as an enteric-coated tablet. Interestingly, Jansen et al. [97] subsequently found that the drug was destabilised by degradation products within these enteric polymers. The authors found that succinyl and phthalyl residues from the hydroxypropyl methylcellulose acetate succinate (HPMCAS) and hydroxypropyl methylcellulose phthalate (HPMCP) formed... 

In this procedure, the HPLC analysis is carried out on a DuPont Zorbax ODS column using methanol, acetonitrile and water 10 2 1 at the mobile phase. This system resolves vitamins D3 from D2 and from degradation products and other fat soluble vitamins. Didecyl and dinonyl phthalate were used as the internal standards. The latter was included for use in the event that extraneous peaks interfered with the didecyl phthalate peak. Figure 11 shows a chromatogram of an extract of a multivitamin formulation with the two added internal standards. 

The degradation products from the oxidation of a number of H-coal samples were qualitatively quite similar. The major compounds identified as methyl esters included propionate, butyrate, oxalate, malonate, methylmalon-ate, maleate, succinate, methylsuccinate, citraconate, glutarate, dimethylsuc-cinate, methylglutarate, adipate, methylethylmaleate, methyladipate, me-thoxysuccinate, benzoate, naphthoate, phthalate, and terephthalate. 

Due to the fact that BBr3 degradation affects also ester linkages no phthalates were observed. Accordingly, an increasing amount of the degradation product phthalic acid was observed. 

Methods for Determining Parent Compounds and Degradation Products in Environmental Media. Good methods with adequate sensitivity and selectivity are available for detecting and quantifying di- -butyl phthalate contamination in water, air, soil, and waste samples. Soil, water, and food are the media of most concern for human exposure to di- -butyl phthalate. The basic methods of extraction followed by high resolution GC (with derivatization of sample) or HPLC-MS have... 

Cellulose acetate plasticized by 10 wt% of diethyl phthalate had the same biodegradation rate, measured by conversion of carbon to CO2, as uiqrlasticized polymer. At the same time, the plasticizer decomposed very rapidly to harmless degradation products. After 10 weeks more than 80% plasticizer was converted compared to about 20% polymer conversion. 

Alkyl phthalate Alkyl adipates Alkyl azealates Alkyl citrates Alkyl sebacates Alkyl glycollates Alkyl phosphates Tetrahydrofuran extraction, GLC (inclndes determination of alcohol degradation products) [32]... 

Allen et al. (106) studied the thermal and UV degradation of PECT samples and the degradation products where characterized by fluorescence and observed the presence of mono and dihydroxytere-phthalate cromophores in the degraded samples. They also studied (107) the thermal and photochemical oxidation of PECT by chemiluminescence and evaluated the influence of stabilizers. They concluded that the hydroperoxide sites formed during oxidation were responsible for the chemiluminescence response. 

The degradation of isoquinoline by Alcaligenes faecalis strain Pa and Pseudomonas diminuta strain 7 (Roger et al. 1990, 1995) is mediated by an oxidoreductase that produces 1,2-dihydroiso-quinoline-l-one, followed by ring fission with the production of o-phthalate and oxidation to 3,4-dihydroxybenzoate (Figure 3.38). The oxidoreductase is purified and like most typical aza-rene oxidoreductases contains, per mole, 0.85 g atoms of Mo, 3.9 g atoms of Fe, and acid-labile S (Lehmann et al. 1994). 

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