Phthalate esters experiment

Work is in progress to validate the MAE method, proposed for EPA, in a multi-laboratory evaluation study. Nothing similar has been reported for additives in polymeric matrices. Dean el al. [452] have reviewed microwave-assisted solvent extraction in environmental organic analysis. Chee et al. [468] have reported MAE of phthalate esters (DMP, DEP, DAP, DBP, BBP, DEHP) from marine sediments. The focus to date has centred on extractions from solid samples. However, recent experience suggests that MAE may also be important for extractions from liquids. 

Although the metabolism of several phthalate esters has been studied in vitro, essentially all of the in vivo studies have involved DEHP. A summary of these experiments which involved exposure offish to aqueous - C-DEHP is presented in Table IV (11,12). Tissue C was isolated and separated into parent and the various metabolites by preparative thin layer chromatography on silica gel. Metabolites were hydrolyzed where appropriate and identified by gas chromatography-mass spectroscopy. In whole catfish, whole fathead minnow and trout muscle, the major metabolite was the monoester while in trout bile the major metabolite was the monoester glucuronide. The fact that in all cases the major metabolite was monoester or monoester glucuronide despite the differences in species, exposure level and duration, etc. represented by these data, suggests that hydrolysis of DEHP to monoester is important in the biotransformation of DEHP by fish. 

A series of comparative experiments using either phthalate esters or cyclohexanoic esters have been presented (15). For example. 

Jensen et al.16 also studied the decomposition of 5-ethoxythiatriazole in dibutyl phthalate solution in the presence of trichloroacetic acid, tripentylamine, 4-benzylpyridine, anhydrous aluminum chloride, or trinitrobenzene, but practically no effect on the reaction rate was observed. However, later experiments have shown that the decomposition can indeed by enhanced catalytically by Lewis acids under conditions where the catalyst is not sequestered by complex formation with the solvent.19 Thus the addition of aluminum chloride to 5-phenylthiatriazole in benzene causes a brisk evolution of nitrogen at room temperature, and if instead boron tribromide is added, a rather violent reaction sets in. However, when esters or ethers are used as... 

A six-step synthesis of ninhydrin starting with a double ester condensation of dimethyl phthalate with ethyl acetate is presented as a student experiment A new synthesis involves in the first step dropwise addition of diethyl phthalate to a suspension of sodium methoxide in dimethyl sulfoxide which is stirred with a... 

It has already been mentioned that a large number of components are used for the construction of wood-based furniture. In addition to the compounds described earlier, a large spectrum of volatile organics can be found in emission studies (Salthammer, 1997b). The main sources for formaldehyde (which is not considered here), phenol and acetic acid are substrates such as particle board and MDF. BHT is a common antioxidant. Volatile plasticizers include dimethyl phthalate (DMP), dibutyl phthalate (DBP), as well as esters of adipic acid and sebacic acid. Further important compound groups are amines, siloxanes, carboxylic acids and naphthalenes. The identification of special substances does not only require suitable analytical equipment. Both experience and detailed knowledge of the chemical composition of furniture are also necessary. 

Two grms. of the oil are heated with 2 grms. of phthalic anhydride and 2 c.c. of benzene for two hours on a water-bath. The mixture is allowed to cool, and shaken for ten minutes with 60 c.c. of semi-normal aqueous caustic potash, in a stoppered flask. At the end of this time the anhydride is converted into neutral phthalate, and the acid geranyl ester into its potassium salt. The excess of alkali is titrated with seminormal sulphuric acid. By deducting from the proportion of alkali absorbed by the quantity of phthalic anhydride used, the quantity of alkali used up in the experiment, the quantity of alkali absorbed by the geranyl ester is obtained, and hence the percentage of geitiniol can be calculated. The results of this method applied to the above mixtures were as follows —... 

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