Dioctyl-phthalate

By far the largest volume synthetic alcohol is 2-ethylexanol [104-76-7] CgH gO, used mainly in production of the poly(vinyl chloride) plasticizer bis(2-ethylhexyl) phthalate [117-81-7], commonly called dioctyl phthalate [117-81-7] or DOP (see Plasticizers). A number of other plasticizer... 

Pollutants. The problems posed by ak pollutants are very serious. Within a museum, measures can be taken to remove harmful substances as efficiently as possible by means of the installation of appropriate filter systems in the ventilation equipment. Proposed specification values for museum climate-control systems requke filtering systems having an efficiency for particulate removal in the dioctyl phthalate test of 60—80%. Systems must be able to limit both sulfur dioxide and nitrogen dioxide concentrations <10 /ig/m, and ozone to <2 /ig/m. ... 

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). 

Specifically MSA has been found to be more effective than -toluenesulfonic acid and sulfuric acid in preparing dioctyl phthalate (405). A U.S. patent also discloses its use to prepare light-colored fatty esters (406). It is also important as a catalyst to prepare acrylates, methacrylates, adipates, phthalates, trimeUitates, thioglycolates, and other esters. 

Stannous Oxalate. Stannous oxalate, Sn(C20 (mol wt 206.71, dec 280°C, sp gr 3.56 at 18°C), is a white crystalline powder, is soluble in hot concentrated hydrochloric acid and mixtures of oxaHc acid and ammonium oxalate, and is insoluble in water, toluene, ethyl acetate, dioctyl phthalate, THF, isomeric heptanes, and acetone (171). It is prepared by precipitation from a solution of stannous chloride and oxaHc acid and is stable indefinitely. 

Fig. 4. SmaH-angle x-ray scattering pattern from PVC plasticized with 20 parts per hundred resin of dioctyl phthalate (18).

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. 

Other large-volume esters are vinyl acetate [108-05-4] (VAM, 1.15 x 10 t/yr), methyl methacrylate [80-62-6] (MMA, 0.54 x 10 t/yr), and dioctyl phthalate [117-81-7] (DOP, 0.14 x 10 t/yr). VAM (see Vinyl polymers) is produced for the most part by the vapor-phase oxidative acetoxylation of ethylene. MMA (see Methacrylic polymers) and DOP (see Phthalic acids) are produced by direct esterification techniques involving methacryHc acid and phthaHc anhydride, respectively. 

FIG. 22-36 Efficiency of an electrofilter as a function of gas flow rate at 5 different voltages. Experimental materials l- im aerosol of dioctyl phthalate glass-fiher filter. Symbols O, no voltage applied A, 2 kV , 3.5 kV , 5 kV , 7 kV. After Fielting et ah, Dielectrophoretic Filtration of Solid and Liquid Aerosol Particulates, Prepr. 75-32.2, 68th ann. meet., AirPollut. Conttol Assoc., Boston, June 1975.)... 

Dioctyl phthalate Lab method using Tenax sorbent tubes, solvent desorption and gas chromatography 32... 

Produced from PVC compounds containing plasticizers such as dioctyl phthalate, this is a flexible sheeting suitable for lining tanks made from steel and concrete. The maximum temperature at which this lining can be used is 60°C. 

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).

Flow markers are often chosen to be chemically pure small molecules that can fully permeate the GPC packing and elute as a sharp peak at the total permeation volume (Vp) of the column. Examples of a few common flow markers reported in the literature for nonaqueous GPC include xylene, dioctyl phthalate, ethylbenzene, and sulfur. The flow marker must in no way perturb the chromatography of the analyte, either by coeluting with the analyte peak of interest or by influencing the retention of the analyte. In all cases it is essential that the flow marker experience no adsorption on the stationary phase of the column. The variability that occurs in a flow marker when it experiences differences in how it adsorbs to a column is more than sufficient to obscure the flow rate deviations that one is trying to monitor and correct for. 

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