Dioctyl Phthalate DOP

Dioctyl phthalate, (also known as di-2-ethylhexyl phthalate (DEHP)) was the highest volume member of a class of synthetic plasticizers called the phthalates. Other members of this class of phthalate plasticizers Include butyl benzyl phthalate (BBP), di-isononyl phthalate (DINP), di-isodecyl phthalate (DIDP), and di-n-octyl phthalate (DNOP). Global production of phthalates as a group was about 12 billion pounds in 2008. However, most of the phthalates are used by the plastics industry (specifically In polyvinyl chloride compounds). Probably less than 5% is actually used by the rubber industry. 

In the rubber Industry, DOP is needed for use as a plasticizer in compounds based on polar elastomers such as nitrile rubber or polychloroprene. Since DOP is a polar plasticizer, it is compatible with polar elastomers. If a nonpolar plasticizer such as 

In this first decade of the new millennium there began rising environmental concerns regarding the use of phthalate plasticizers. Published literature indicates that some or all of the phthalates may also function as reproductive toxins in the environment. This had an immediate impact on the use of these plasticizers in toys for children, for example. The European Union is now considering banning the use of certain phthalate plasticizers by or before 2015. These new environmental concerns have caused a reduction in consumption of the phthalate plasticizers, including DOP. 

Feedstock dependency is based on 2-ethylhexanol and phthalic anhydride. 

ASTM D1992 can be used to ciassify phthaiate piasticizers for rubber use. 

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Fig. 2. The effect of antimony oxide on the oxygen index of poly(vinyl chloride) plasticized with dioctyl phthalate (DOP), (—...

Raw Materials. PVC is inherently a hard and brittle material and very sensitive to heat it thus must be modified with a variety of plasticizers, stabilizers, and other processing aids to form heat-stable flexible or semiflexible products or with lesser amounts of these processing aids for the manufacture of rigid products (see Vinyl polymers, vinyl chloride polymers). Plasticizer levels used to produce the desired softness and flexibihty in a finished product vary between 25 parts per hundred (pph) parts of PVC for flooring products to about 80—100 pph for apparel products (245). Numerous plasticizers (qv) are commercially available for PVC, although dioctyl phthalate (DOP) is by far the most widely used in industrial appHcations due to its excellent properties and low cost. For example, phosphates provide improved flame resistance, adipate esters enhance low temperature flexibihty, polymeric plasticizers such as glycol adipates and azelates improve the migration resistance, and phthalate esters provide compatibiUty and flexibihty (245). 

Plasticizers. Monomeric (mol wt 250—450) plasticizers (qv) are predominantiy phthalate, adipate, sebacate, phosphate, or trimeUitate esters. Organic phthalate esters like dioctyl phthalate (DOP) are by far the most common plasticizers in flexible PVC. Phthalates are good general-purpose plasticizers which impart good physical and low temperature properties but lack permanence in hot or extractive service conditions and are therefore sometimes called migratory plasticizers. Polymeric plasticizers (mol wt up to 5000 or more) offer an improvement in nonmigratory permanence at a sacrifice in cost, low temperature properties, and processibiHty examples are ethylene vinyl acetate or nitrile polymers. 

Uses. Phthabc anhydride is used mainly in plasticizers, unsaturated polyesters, and alkyd resins (qv). PhthaUc plasticizers consume 54% of the phthahc anhydride in the United States (33). The plasticizers (qv) are used mainly with poly(vinyl chloride) to produce flexible sheet such as wallpaper and upholstery fabric from normally rigid polymers. The plasticizers are of two types diesters of the same monohydric alcohol such as dibutyl phthalate, or mixed esters of two monohydric alcohols. The largest-volume plasticizer is di(2-ethylhexyl) phthalate [117-81-7] which is known commercially as dioctyl phthalate (DOP) and is the base to which other plasticizers are compared. The important phthahc acid esters and thek physical properties are Hsted in Table 12. The demand for phthahc acid in plasticizers is naturally tied to the growth of the flexible poly(vinyl chloride) market which is large and has been growing steadily. 

Often dioctyl phthalate (DOP). Also dioctyl adipate (DOA). 

Di-2-EthylhexylPhthalate. In Western Europe, di-2-ethylhexyl phthalate [117-81-7] (DEHP), also known as dioctyl phthalate (DOP), accounts for about 50% of all plasticizer usage and as such is generally considered as the industry standard. The reason for this is that it is in the mid-range of plasticizer properties. DEHP (or DOP) is the phthalate ester of 2-ethyIhexanol, which is normally manufactured by the dimerization of butyraldehyde (eq. 2), the butyraldehyde itself being synthesized from propylene (see Butyraldehydes). 

Vehicles are selected by two methods. In one a concentrate is designed directiy for a resin system, the resin itself, or a compatible resin. Thus when the concentrate is made there is a minimal effect on the properties of the final color. In PVC, often a plasticizer such as dioctyl phthalate (DOP) is used. In the other method, concentrates are made with a commercial universal concentrate vehicle. Concentrate manufacturers and some resin manufacturers have developed vehicles that can incorporate many types of colorants and can be used across many classes of polymers without adversely affecting final product performance. 

The polarity of the polyethers makes them incompatible with hydrocarbon-type plasticizers, which tend to bleed. Effective plasticizers are ethers such as di(butoxyethoxyethyl)formal [143-29-3] (Thiokors TP-90B), esters such as di(2-ethylhexyl) phthalate [117-81-7] dioctyl phthalate (DOP), polyesters such as Paraplex G50 (Rohm and Haas), and ether—esters such as di(butoxyethoxyethyl) adipate [114-17-3] (Thiokol s TP-95). The lower mol wt plasticizers, DOP, TP-90B, and TP-95 improve vulcanizate low temperature performance. The polymeric plasticizers maintain higher temperature and long-term aging properties. Epoxidized plasticizers should be avoided because they interfere with vulcanization. 

Figures 6.6 and 6.7 show the effect of a solvent separation column. In the case of Fig. 6.7, the upper part of the figure shows the chromatogram of polyvinyl chrolide, which contains dioctyl phthalate (DOP), using KF-806L. In this case, DOP is not separated from a solvent peak. However, DOP can be separated from the solvent peak using KF-800D in conjunetion with KF-806L (Table 6.6).

Note Phthalates, especially di-2-ethylhexyl phthalate (also known as dioctyl phthalate, DOP), are commonly used plasticizers in synthetic polymers. Unfortunately, they are extracted from the polymer upon exposure to solvents such as dichloromethane, chloroform or toluene, e.g., from syringes, tubing, vials etc. Therefore, they are often detected as impurities. They are easily recognized from their peaks at m/z 149 (often base peak), m/z 167, and [M-(R-2H)] m/z 279 in case of DOP). The molecular ion is often absent in their El spectra. 

Richardson et al (1989) performed similar measurements for droplets of sulfuric acid and dioctyl phthalate (DOP) in a quadrupole. Sulfuric acid droplets exploded prior to the Rayleigh limit (at 84 20% of the Rayleigh limit), and the DOP droplets fissioned approximately at the Rayleigh limit... 

Chylek et al. (1983) showed that, by comparing experimental resonance spectra with spectra computed using Mie theory, the size and refractive index of a microsphere can be determined to about one part in 10. Numerous investigators have used resonance spectra to determine the optical properties of microspheres since Ashkin and Dziedzic observed resonances. A recent example is the droplet evaporation study of Tang and Munkelwitz (1991), who measured the vapor pressures of the low-volatility species dioctyl phthalate (DOP), glycerol, oleic acid, and methanesulfonic acid (MSA). This... 

Phthalic anhydride reacts with alcohols such as 2-ethylhexanol to form liquids that impart great flexibility when added to many plastics without hurting their strength. Most of these plasticizers, about 80%, are for poly(vinyl chloride) flexibility. Dioctyl phthalate (DOP), also called di-(2-ethylhexyOphthalate (DEHP), is a common plasticizer. 

Figure 9.63, for example, plots log K against log pL for the partitioning of a series of PAH (see Chapter 10) between the gas phase and particles of either dioctyl phthalate (DOP) or secondary organic aerosol (SOA) generated from the photooxidation of gasoline vapor (Liang et al., 1997). The slope of the plot for uptake into DOP is 1.09 and that for uptake into SOA is... 

FIGURE 9.63 Plots of om-phase-normalized gas-particle partitioning constant log Kp iun vs logarithm of the subcooled liquid vapor pressure, log pL, for a series of semivolatile PAHs partitioning on ( ) dioctyl phthalate (DOP) or (a) secondary organic aerosol (SOA) from photooxidized gasoline vapor. PAHs are as follows naphthalene, A acenaphthalene, B fluorene, C and C phenanthrene, D and D anthracene, E and E fluoranthene, F and F pyrene, G and G chrysene, H (adapted from Liang el al., 1997). 

FIGURE 11.62 Experimental calibration curves for a commercial single-particle counter and two types of calibration aerosols dioctyl phthalate (DOP) and coal dust (adapted from Whitby and Willeke, 1979). 

Electrodes based on 9 but no nucleobase derivative [3.0 wt% 9 bis(2-ethylhexyl) phthalate ( dioctyl phthalate , DOP) as the membrane solvent] showed similar potentiometric responses to 5 -GMP and 5 -AMP (Figure 8a), which is not surprising because cation 9 cannot interact specifically with the base pairing site of nucleotides. The EMF slope (-29 mV decade" 0.1 M HEPES-NaOH buffer solution, pH 6.8) was much greater than in case of the electrode based on the macrocyclic pentaamine 1 (-15 mV decade" ) and corresponds to the slope as expected for a dianion according to the Nemstian equation. Extraction experiments confirmed that at this pH it is indeed the dianion that enters the organic phase. 

Thus the presence of 40 mass percent of dioctyl phthalate (DOP) plasticizer to PVC lowers the Tg from 395 to 270 K, and hence the plasticized PVC is flexible at room temperature. Solvents have similar effects on the Tg, but of course a volatile solvent is much less permanent than a high-boiling plasticizer. 

Since cellulose nitrate is intractable, in 1870 John W. Hyatt added camphor as a plasticizer to flexibilize this plastic. Some 60 years later, Waldo Semon used tricresyl phosphate as a plasticizer for PVC. Dialkyl phthalates, such as dioctyl phthalate (DOP) and other alkyl phthalates which replaced the more toxic tricresyl phosphate, are now used as plasticizers primarily for PVC at an annual rate of 1 million tons. 

DOP polydisperse aerosol generated by blowing air through liquid dioctyl phthalate (DOP) at room temperature. The approximate light-scattering mean droplet size distribution of the aerosol is ... 

A systematic study of the domain spacing scaling in two nearly symmetric PS-PI diblocks in neutral solvents was also undertaken by Hashimoto et al. (1983b). Results of S AXS experiments on these polymers dissolved in toluene and dioctyl phthalate (DOP) were summarized in a scaling relationship for the domain spacing in the ordered phase in the semidilute and concentrated regimes (0.15 < 4> < 0.6)... 

Propylene glycol methyl ether acetate. d(CH3)2CHCOOCH2C(CH3)2CH(OH)CH(CH3)2. e Dioctyl phthalate (DOP). 

Viscosity Analysis. Rheological analyses of the unground spray dried resins in dioctyl phthalate (DOP) plastisols gave the viscosity flow curves in Figures V-VIII. Characteristic data are presented in Tables II and III. 

The sample was a solution of polystyrene (PS) dissolved in dioctyl phthalate (DOP). This system has a theta temperature of approximately 22°C [183] and has been the subject of most of the studies investigating flow-induced phase transitions in polymer solutions. The particular sample used here had a molecular weight for PS of 2 million, a poly-dispersity of MW/MN = 1.06, and a concentration of 6%. This results in a semidilute... 

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