Ethylhexyl branched

Fig. 9.5 Synthetic routes to PPVs. R is a long chain substituent in MEH-PPV R is an ethylhexyl branched chain.

Intermediate that can result in formation of 2-ethylhexyl branching in LDPE (See Figure 2.3)... 

Figure 2.3 Mechanism of formation of 2-ethylhexyl branch in LDPE. As in backbiting mechanism for n-butyl group formation, homolytic scission of a CH bond occurs down the chain. is a polymeric alkyl group.

Figure 2.3 Mechanism for formation of 2-ethylhexyl branch in LDPE 28...

Diesters have been produced primarily by esterification of a C -branched-chain alcohol with adipic (C ), a2elaic (C ), or sebacic (C q) diacid. Di(2-ethylhexyl)sebacate [122-62-3] was quite generally used in military greases and MIL-L-7808 jet engine oil, but more recent demands and price competition have led to use of a variety of diesters. 

Plasticizers. Plasticizers are materials that soften and flexibilize inherently rigid, and even britde polymers. Organic esters are widely used as plasticizers in polymers (97,98). These esters include the benzoats, phthalates, terephthalates, and trimeUitates, and aUphatic dibasic acid esters. Eor example, triethylene glycol bis(2-ethylbutyrate) [95-08-9] is a plasticizer for poly(vinyl butyral) [63148-65-2] which is used in laminated safety glass (see Vinyl POLYMERS, poly(vinyl acetals)). Di(2-ethyUiexyl)phthalate [117-81-7] (DOP) is a preeminent plasticizer. Variation of acid and/or alcohol component(s) modifies the efficacy of the resultant ester as a plasticizer. In phthalate plasticizers, molecular sizes of the alcohol moiety can be varied from methyl to tridecyl to control permanence, compatibiUty, and efficiency branched (eg, 2-ethylhexyl, isodecyl) for rapid absorption and fusion linear (C6—Cll) for low temperature flexibiUty and low volatility and aromatic (benzyl) for solvating. Terephthalates are recognized for their migration resistance, and trimeUitates for their low volatility in plasticizer appHcations. 

In sodium bis(2-ethylhexyl) phosphate microemulsions, which are composed of cylindrical micelles in the dilute region, it has been observed that the formation of micellar clusters is characterized by a branched structure as the volume fraction (<1>) of the aggregates increases. At d> > 0.2, these clusters mutually overlap, forming a network expanded overall [283]. 

Considerable confusion exists in the literature about the TRI release reporting data and monitoring data available for di-ft-octylphthalatc and its more common branched isomer, di(2-ethylhexyl)phthalate (EPA 1992a Vista Chemical 1992). The confusion exists because the terms "dioctyl phthalate" and "DOP" are often used as synonyms for di(2-ethylhexyl)phthalate, which is the largest volume plasticizer used in PVC. Consequently, some of the historical release and monitoring data reported in the literature as "dioctyl phthalate" and "DOP" refer to the more common branched isomer rather than di-ft-octylphthalate. 

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. 

Exposure Levels in Humans. This information is necessary for assessing the need to conduct health studies on these populations. Di- -oclylphthalatc has historically been reported to have been found in human adipose tissue (EPA 1986d). However, more recent information indicates that the compound detected was actually the branched di(2-ethylhexyl) isomer (EPA 1989b). Additional information on the concentrations of di-n-octylphthalate in human tissues and fluids, particularly for populations living near hazardous waste sites, is needed to assess potential human exposure to the compound. 

Di(2-ethylhexyl) phthalate was found in both the packaging and in a number of contacted foods sampled in a 1985-89 survey as part of the Canadian Health Protection Branch Total Diet Program. Low levels (65 lg/kg [L] average in beverages and 29 ig/kg average in foods) associated with the use of di(2-ethylhexyl) phthalate-plasticized cap or lid seals were found in a variety of glass-packaged foods. It was... 

Polyethylene also contains ethyl side chains. These are formed according to the reactions in Scheme 13.3 leading to 2-ethylhexyl and 1,3-paired diethyl branches.220-222 Formation of such new branching has high probability since the newly formed radical is in close proximity to the chain backbone. 

With cyclic amides, N-alkyl-caprolactams, the tendency was similar, namely no obvious change in the extraction of Th(IV) and U(VI) was observed in the range 102—104 Gy. But if the gamma-ray irradiation dose was higher than 104 Gy, >U(Vi, decreased with the increased dose, as observed for TBP. This effect was stronger when one radical on nitrogen was branched (2-ethylhexyl instead of n-octyl) (201). 

Nevertheless, the octyl sulfate CAD spectrum yields sufficient information to allow the compound to be distinguished from isomeric 2-ethylhexyl sulfate (for a comparison, see ref. 8). The branching of the 2-ethylhexyl sulfate causes suppression of fragmentation at the branch point in a fashion analogous to that seen for the carboxylates and for the steroid (see Figure 3). 

Higher alkoxides, such as tetra(2-ethylhexyl) titanate, TYZOR TOT [1070-10-6]9 can be prepared by alcohol interchange (transesterification) in a solvent, such as benzene or cyclohexane, to form a volatile azeotrope with the displaced alcohol, or by a solvent-free process involving vacuum removal of the more volatile displaced alcohol. The affinity of an alcohol for titanium decreases in the order primary > secondary > tertiary, and branched > unbranched. Exchange processes are more convenient than direct synthesis of tetraalkoxide from TiCl an alcohol, and a base because a metal chloride need not be handled. However, in general, traces of impurities of mixed tetraalkyl titanates can result. 

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