Phthalate ester isomers

Plasticizer Efficiency. This is a measure of the concentration of plasticizer required to impart a specified softness to PVC. Such a softness of material may be measured as a British Standard Softness (BSS) or a Shore hardness (Pig. 1). Por a given acid constituent of plasticizer ester, ie, phthalate, adipate, etc, plasticizer efficiency decreases as the carbon number of the alcohol chain increases, eg, for phthalate esters efficiency decreases in the order DBP > DIHP > DOP > DINP > DIDP > DTDP. An additional six parts per hundred in PVC of DIDP rather than DOP is required to give a hardness of Shore 80 when ah. other formulation ingredients remain constant. The consequence of this depends on the overall formulation and product costs. In addition to size of the carbon number of the alcohol chain, the amount of branching is also significant the more linear isomers are of greater efficiency. 

In the 0X0 industry, the term iso denotes a mixture of isomers and does not refer to the lUPAC definition. Therefore, the abbreviations included in Table 28.2 indicate when a phthalate ester is a mixture of branched or linear isomers (i.e., DNP for linear di-w-nonylphthalate, and DINP for branched diisononylphthalate). With the exception of di-(2-ethyUiexyl) phthalate, higher molecular weight phthalate esters (alkyl chains > 6 carbons) are mixtures based on the alcohols used for its production. Eor example, DINP is a mixture of di-C8-C10 branched alkylesters, containing principally isomers with nine carbon alkyl chains. In the same way, the term DIDP refers to a mixture of di-C9-ll branched alkyl esters (Cl0-rich) of phthalic acid. 

Council Regulation 793/93 divides existing chemicals into two categories High Production Volume Chemicals (HPVC), produced or imported in quantities exceeding 1000 tonnes per year and Low Production Volume Chemicals (LPVC), produced or imported in quantities between 10 and 1000 tonnes per year. The hst of HPVCs includes 22 phthalic acid esters, both single compounds and technical mixtures with dilferent isomers. A further 11 phthalates are compiled in the list of LPVC. The most commonly used phthalate esters are DEHP (which accounts for around half of consumption in Western Europe, DINP and DIDP, which represents the 52.2% of phthalate consumption in the United States and more than 85% of phthalate esters production in Western Europe. ... 

SP-2401" and 3% SP-2250. ° Detectors used by EPA standards procedures, include photoionization (PID)," electron capture (ECD)," Eourier transform infrared spectrometry (PTIR), " and mass spectrometry detectors (MSD)." ° Method 8061 employs an ECD, so identification of the phthalate esters should be supported by al least one additional qualitative technique. This method also describes the use of an additional column (14% cyanopropyl phenyl polysiloxane) and dual ECD analysis, which fulfills the above mentioned requirement. Among MSDs, most of the procedures employ electron impact (El) ionization, but chemical ionization (CI) ° is also employed. In all MSD methods, except 1625, quantitative analysis is performed using internal standard techniques with a single characteristic m/z- Method 1625 is an isotope dilution procedure. The use of a FTIR detector (method 8410) allows the identification of specific isomers that are not differentiated using GC-MSD. 

DiisononylPhthalate andDiisodeeylPhthalate. These primary plasticizers are produced by esterification of 0x0 alcohols of carbon chain length nine and ten. The 0x0 alcohols are produced through the carbonylation of alkenes (olefins). The carbonylation process (eq. 3) adds a carbon unit to an alkene chain by reaction with carbon monoxide and hydrogen with heat, pressure, and catalyst. In this way a Cg alkene is carbonylated to yield a alcohol a alkene is carbonylated to produce a C q alcohol. Due to the distribution of the C=C double bond ia the alkene and the varyiag effectiveness of certain catalysts, the position of the added carbon atom can vary and an isomer distribution is generally created ia such a reaction the nature of this distribution depends on the reaction conditions. Consequendy these alcohols are termed iso-alcohols and the subsequent phthalates iso-phthalates, an unfortunate designation ia view of possible confusion with esters of isophthaUc acid. 

Butylcyclohexanol has been prepared from />-/-butylphenol by reduction under a variety of conditions.3 4 Winstein and Holness5 prepared the pure trans alcohol from the commercial alcohol by repeated crystallization of the acid phthalate followed by saponification of the pure trans ester. Eliel and Ro 6 obtained 4-f-butylcyclohexanol containing 91% of the trans isomer by lithium aluminum hydride reduction of the ketone. Iliickel and Kurz 7 reduced />-/-butylphenol with platinum oxide in acetic acid and then separated the isomers by column chromatography. 

Exposure Levels in Environmental Media. Reliable monitoring data for the levels of di- -octylphthalate in contaminated media at hazardous waste sites are needed so that the information obtained on levels of di-ra-octylphthalate in the environment can be used in combination with the known body burden of di-w-octylphthalate to assess the potential risk of adverse health effects in populations living in the vicinity of hazardous waste sites. Di-u-octylphthalate has been detected in ambient air, rain, surface water, groundwater, and sediment. However, as a result of the confusion about the nomenclature for octylphthalate esters, much of the historical monitoring data available actually pertain to the branched isomer, di(2-ethylhexyl)phthalate (Vista Chemical 1992). Therefore, little current information specific to the /1-octyl isomer is available regarding concentrations of the compound in foods, drinking water, and environmental media, particularly with respect to media at hazardous waste sites. The lack of monitoring data precludes the estimation of human exposure via intake of or contact with contaminated media. 

T. Takahashi, A. Tanaka, Biochemical Studies on Phthalic Esters. V. Comparative Studies on in vitro Hydrolysis of Di-V-butyl Phthalate Isomers in Rats Arch. Toxicol. 1989, 63, 72-74. 

Takahashi T, Tanaka A. 1989. Biochemical studies on phthalic esters. V. Comparative studies on in vitro hydrolysis of di- -butyl phthalate isomers in rats. Arch Toxicol 63 72-74. 

Diisooctyl phthalate is a mixture of phthalie esters of octylalcohd isomers physical prqperties (boiling point, melting point and flash point) differ from those given above for DOP. ... 

Dinonyl phthalate (mainly 3,5 -trimethylhexyl phthalate isomer) [14103-61-8, 28553-12-0, 84-76-4] M 418.6, m 26-29", b 170"/2mm, d 4 0.9640, n p 1.4825. Wash the ester with aqueous Na2C03 then shake it with water. Ether is added to break the emulsion, and the solution is washed twice with water, and dried (CaCl2). After evaporating the ether, the residual liquid is distilled three times under reduced pressure. It is stored in a vacuum desiccator over P2O5. [Beilstein 9 IV 3183.]... 

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