Volatile vinyl chloride

When ethylene dichloride (bp, 84 C) is used for the preparation of vinyl chloride, it is treated with dilute sodium hydroxide at approximately 150 C in a pressure vessel provided with an agitator. By means of a suitable fractional condensing system, the vapors of dichloroethane are condensed and returned to the reactor, the water of reaction is removed, and the volatile vinyl chloride (bp, IS.O C) is withdrawn and liquefied in a low-temperature condenser. 

The purpose of this subpart is to protect employees from exposure to toxic and hazardous substances in the workplace. It covers the Permissible Exposure Limits (PEL) for all air contaminants including all gases, vapors, and dusts. Some of the contaminants covered underthis subpart include asbestos, coal tar pitch volatiles, vinyl chloride, inorganic arsenic, lead, cadmium, benzene, coke-oven emissions, bloodborne pathogens, cotton dust, ethylene oxide, and formaldehyde. 

Automated analyzers may be used for continuous monitoring of ambient poUutants and EPA has developed continuous procedures (23) as alternatives to the referenced methods. Eor source sampling, EPA has specified extractive sampling trains and analytical methods for poUutants such as SO2 and SO [7446-11-9] sulfuric acid [7664-93-9] mists, NO, mercury [7439-97-6], beryUium [7440-41-7], vinyl chloride, and VOCs (volatile organic compounds). Some EPA New Source Performance Standards requite continuous monitors on specified sources. 

Antagonism between antimony oxide and phosphoms flame retardants has been reported in several polymer systems, and has been explained on the basis of phosphoms interfering with the formation or volatilization of antimony haUdes, perhaps by forming antimony phosphate (12,13). This phenomenon is also not universal, and depends on the relative amounts of antimony and phosphoms. Some useful commercial poly(vinyl chloride) (PVC) formulations have been described for antimony oxide and triaryl phosphates (42). Combinations of antimony oxide, halogen compounds, and phosphates have also been found useful in commercial flexible urethane foams (43). 

Process water streams from vinyl chloride manufacture are typically steam-stripped to remove volatile organics, neutralized, and then treated in an activated sludge system to remove any nonvolatile organics. If fluidized-bed oxychlorination is used, the process wastewater may also contain suspended catalyst fines and dissolved metals. The former can easily be removed by sedimentation, and the latter by precipitation. Depending on the specific catalyst formulation and outfall limitations, tertiary treatment may be needed to reduce dissolved metals to acceptable levels. 

Dichloroethane [107-06-2] ethylene chloride, ethylene dichloride, CH2CICH2CI, is a colorless, volatile Hquid with a pleasant odor, stable at ordinary temperatures. It is miscible with other chlorinated solvents and soluble in common organic solvents as well as having high solvency for fats, greases, and waxes. It is most commonly used in the production of vinyl chloride monomer. 

Diesters. Many of the diester derivatives are commercially important. The diesters are important plasticizers, polymer intermediates, and synthetic lubricants. The diesters of azelaic and sebacic acids are useflil as monomeric plasticizing agents these perform weU at low temperatures and are less water-soluble and less volatile than are diesters of adipic acid. Azelate diesters, eg, di- -hexyl, di(2-ethylhexyl), and dibutyl, are useflil plasticizing agents for poly(vinyl chloride), synthetic mbbers, nitroceUulose, and other derivatized ceUuloses (104). The di-hexyl azelates and dibutyl sebacate are sanctioned by the U.S. Food and Dmg Administration for use in poly(vinyl chloride) films and in other plastics with direct contact to food. The di(2-ethylhexyl) and dibenzyl sebacates are also valuable plasticizers. Monomeric plasticizers have also been prepared from other diacids, notably dodecanedioic, brassyflc, and 8-eth5lhexadecanedioic (88), but these have not enjoyed the commercialization of the sebacic and azelaic diesters. 

Viking Lander, 355 vinyl chloride, 764 virial coefficient, 168 virial equation, 168 viscosity, 186 visible light, 4, 6 vision, 113 vitamin, 74 vitamin C, F48 volatile, 310 volt, 492, A4 Volta, A., 483 voltage, 490 voltaic cell, 490 voltaic pile, 483... 

A wide variety of methods have been developed for the detection of residual monomers in polymeric materials. Volatile monomers, for example, acrylonitrile, butadiene, vinyl chloride, etc., are normally determined using headspace GC methods. 

Interpretation of these curves show that Poly (vinyl chloride) (PVC) first loses HC1 later the mixture of unsaturated carbon-carbon backbone and unchanged poly (vinyl chloride) partly degrades to small fragments. Poly (methyl methacrylate) (PMMA), branched polyethylene (HPPE), and polytetrafluorethylene (PTFE) degrade completely to volatile fragments, while a polyimide (PI) partially decomposes, forming a char above 800°C. 

Biological. 1,1-Dichloroethane showed significant degradation with gradual adaptation in a static-culture flask-screening test (settled domestic wastewater inoculum) conducted at 25 °C. At concentrations of 5 and 10 mg/L, percent losses after 4 wk of incubation were 91 and 83, respectively. At a substrate concentration of 5 mg/L, 19% was lost due to volatilization after 10 d (Tabak et ah, 1981). Under anoxic conditions, indigenous microbes in uncontaminated sediments produced vinyl chloride (Barrio-Lage et al, 1986). 

In a continuous-flow mixed-film methanogenic column study, tetrachloroethylene degraded to trichloroethylene with traces of vinyl chloride, dichloroethylene isomers, and carbon dioxide (Vogel and McCarty, 1985). In a static-culture-flask screening test, tetrachloroethylene (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. Significant degradation with gradual adaptation was observed after 28 d of incubation. The amount lost due to volatilization after 10 d was 16 to 23% (Tabak et al., 1981). 

According to the vendor, this technology is capable of removing chlorinated hydrocarbons, aliphatic hydrocarbons, aromatics, benzene, toluene, xylene, carbon tetrachloride, vinyl chloride, dichloromethane, and trichloroethane. Polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), and volatile inorganic solvents can also be removed. The technology is currently in use and is commercially available. 

Biovault technology alone is not an effective treatment for creosote- and pentachlorophenol (PCP)-contaminated soils. Inorganic wastes are not typically treatable biologically, and biovault technology may not be practical for contaminants with low rates of degradation or very high volatility, such as vinyl chloride. 

Researchers believe that the PSVE technology can be used to remove volatile organic compounds (VOCs), halogenated volatile organic compounds (HVOCs), and total petroleum hydrocarbons (TPH). Some chemicals treated with PSVE include carbon tetrachloride, vinyl chloride (VC), chlorobenzene, 1,1-dichloroethane, dichloroethene (DCE), trichloroethane (TCA), and benzene, toluene, ethylbenzene, and xylene (BTEX). 

Vinyl Chloride under Unsaturated Alkyl Halides Volatile Organic Compounds... 

Di(2-ethylhexyl) phthalate is a liquid of low volatility, widely used as a plasticizer in flexible poly(vinyl chloride) products at concentrations of up to 40%, as well as in a number of other minor applications. Occupational exposure occurs mainly by inhalation as an aerosol during its manufacture and its use as a plasticizer in poly(vinyl chloride) product manufacturing plants, at concentrations usually below 1 mg/m. ... 

Useful for highly volatile compounds (often better than activated carbon) methyl chloride, vinyl chloride, chloroform, dimethyl ether, etc. 

Carbonized Resins. A special sorbent made by controlled thermal pyrolysis of polyvinylidene chloride (Dow developmental Adsorbent XF-4175L) (34) was shown to be three to five times more effective for the collection of highly volatile compounds, such as vinyl chloride (Figure 5) and methyl chloride, than the best available activated charcoal (31,36,37). Although this sorbent is not commercially available, Carbosive and Carbosive S show similar collection properties and they are available from gas chromatographic supply houses or may be obtained already packed in small collection tubes (SKC Inc., Eighty Four, PA). 

Coal tar volatiles—coke oven emissions Vinyl chloride... 

The induction of unconsciousness may be the result of exposure to excessive concentrations of toxic solvents such as carbon tetrachloride or vinyl chloride, as occasionally occurs in industrial situations (solvent narcosis). Also, volatile and nonvolatile anesthetic drugs such as halothane and thiopental, respectively, cause the same physiological effect. The mechanism(s) underlying anesthesia is not fully understood, although various theories have been proposed. Many of these have centered on the correlation between certain physicochemical properties and anesthetic potency. Thus, the oil/water partition coefficient, the ability to reduce surface tension, and the ability to induce the formation of clathrate compounds with water are all correlated with anesthetic potency. It seems that each of these characteristics are all connected to hydrophobicity, and so the site of action may be a hydrophobic region in a membrane or protein. Thus, again, physicochemical properties determine biological activity. 

Phthalates. These esters, prepared from o-phthalic anhydride, constitute the most important group of plasticizers from the stand-point of production and sales volume. Among these the dioctyl phthalates are the most widely used in vinyl chloride resins, where they are preferred because they offer a good compromise with respect to a wide range of properties satisfactory volatility, good compatibility, fair low-temperature flexibility,... 

A recent achievement worthy of note is the manufacture of microspheres containing an inert gas, e.g. nitrogen, or a volatile liquid, such as the freons The patent literature contains methods for producing microspheres based on poly(vinyl chloride) and poly(divinyl chloride), containing isobutane or carbon tetrachloride 52>, and based on poly(methyl methacrylate), containing neopentane . Microspheres containing liquid dyes and oils are also used to make syntactic foams 58>. 

Bioremediation and thermal desorption are the most frequently selected innovative technologies for NPL sites with SVOCs, which are the second most common contaminants found at NPL sites. Also, SVE has been selected for some of the most volatile SVOCs (e.g., phenols and naphthalenes). Current research efforts are focused on biodegradation of chlorinated aliphatic hydrocarbons, such as trichloroethylene (TCE) and vinyl chloride, which occur at many sites. Thermal desorption most effectively treats PAHs and PCBs, and it may be particularly useful to pretreat organics prior to metal treatment. 

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