Vinyl chloride Table

Liver cancer can also be a consequence of exposure to hepatotoxic chemicals. Natural hepatocarcinogens include fungal aflatoxins. Synthetic hepato-carcinogens include nitrosoamines, certain chlorinated hydrocarbons, polychlorinated biphenyls (PCBs), chloroform, carbon tetrachloride, dimethyl-benzanthracene, and vinyl chloride.Table 5.15 lists the chemical compounds that induce liver cancer or cirrhosis in experimental animals or... 

A comparison was accomplished with a conventional poly (vinyl chloride) (Table VII) having a molecular weight comparable with that of the homopolymer present in the crude grafting product. 

Table 11.4 lists economic data on the main methods for produdng ethylene dichloride and vinyl chloride. Table 11.5 gives data on the three main types of process for manufacturing chlorine by the electrolysis of sodium chloride. 

Many companies offer proprietary technology for the manufacture of vinyl chloride. Table 12 is a list of process licensers and a brief description of the characteristics of the technology they offer [21],... 

The selectivity of the sensor was tested by simultaneous exposure to VA and each of several other gases and vapors encountered with VA in industrial processes. The chemicals examined included ethyl acetate, methanol, methyl acrylate, methylmethacrylate, mesityl oxide and vinyl chloride. Table I summarizes the results for exposures at 40 C to 50 ppm of VA and each of the other chemicals. As shown, there was no measurable effect on the response to VA. With the exception of methyl acrylate, none of these confounds reacted with the conplex when exposed Individually. The response to 60 ppm of methyl acrylate alone was 10 Hz/mln which is about one-third that of VA at the same concentration. That methyl acrylate does not affect the response to VA during simultaneous exposure is remarkable since it indicates that the VA is exclusively favored in the con etition for reaction with the solid. This observation, coupled with the fact that the strongly-coordinating methanol does not increase the response to VA, is consistent with previous data (22) indicating an associative pathway for the reaction. 

According to this scheme, Q should be equal to zero when the radical is not resonance-stabilized. In fact, very low Q values are obtained for ethylene, vinyl acetate, and vinyl chloride (Table 22-12). Q is taken as unity for the standard, styrene, because the styrene free radical was assumed to have the greatest resonance stabilization. However, a few monomers, such as 2,5-dichlorostyrene, butadiene, and vinylidene cyanide, show higher Q values. The high Q value of isopropyl vinyl ether is inexplicable (experimental error, charge transfer complex ). 

ETHYLENE We discussed ethylene production in an earlier boxed essay (Section 5 1) where it was pointed out that the output of the U S petrochemi cal industry exceeds 5 x 10 ° Ib/year Approximately 90% of this material is used for the preparation of four compounds (polyethylene ethylene oxide vinyl chloride and styrene) with polymerization to poly ethylene accounting for half the total Both vinyl chloride and styrene are polymerized to give poly(vinyl chloride) and polystyrene respectively (see Table 6 5) Ethylene oxide is a starting material for the preparation of ethylene glycol for use as an an tifreeze in automobile radiators and in the produc tion of polyester fibers (see the boxed essay Condensation Polymers Polyamides and Polyesters in Chapter 20)... 

The data in Table 7.6 list the mole fraction of methyl acrylate in the feedstock and in the copolymer for the methyl acrylate (Mi)-vinyl chloride (M2) system. Use Eq. (7.54) as the basis for the graphical determination of the reactivity ratios which describe this system. 

Table 7.6 Values of Fj as a Function of fj for the Methyl Acrylate (Mi)-Vinyl Chloride (M2) System (Data used in Example 7.5)...

Molybdenum Oxides. Molybdenum was one of the first elements used to retard the flames of ceUulosics (2). Mote recently it has been used to impart flame resistance and smoke suppression to plastics (26). Molybdic oxide, ammonium octamolybdate, and zinc molybdate ate the most widely used molybdenum flame retardants. Properties ate given in Table 5. These materials ate recommended almost exclusively for poly(vinyl chloride), its alloys, and unsaturated polyesters (qv). 

Poly(vinyl chloride). PVC is a hard, brittle polymer that is self-extinguishing. In order to make PVC useful and more pHable, plasticizers (qv) are added. More often than not the plasticizers are flammable and make the formulation less flame resistant. Flammability increases as the plasticizer is increased and the relative amount of chlorine decreased, as shown in Table 7. The flame resistance of the poly(vinyl chloride) can be increased by the addition of an inorganic flame-retardant synergist. 

Vlayl fluoride [75-02-5] (VF) (fluoroethene) is a colorless gas at ambient conditions. It was first prepared by reaction of l,l-difluoro-2-bromoethane [359-07-9] with ziac (1). Most approaches to vinyl fluoride synthesis have employed reactions of acetylene [74-86-2] with hydrogen fluoride (HF) either directly (2—5) or utilizing catalysts (3,6—10). Other routes have iavolved ethylene [74-85-1] and HF (11), pyrolysis of 1,1-difluoroethane [624-72-6] (12,13) and fluorochloroethanes (14—18), reaction of 1,1-difluoroethane with acetylene (19,20), and halogen exchange of vinyl chloride [75-01-4] with HF (21—23). Physical properties of vinyl fluoride are given ia Table 1. 

Most of the HCl produced is consumed captively, ie, at the site of production, either in integrated operations such as ethylenedichloride—vinyl chloride monomer (EDC/VCM) plants and chlorinated methane plants or in separate HCl consuming operations at the same location. Captive use of anhydrous HCl accounted for 80—85% of the total demand in 1989. The combined merchant market for anhydrous and aqueous HCl in that same year was about 9.1 X 10 metric tons on the basis of 100% HCl (see Table 12) (73). 

Commonly used materials for cable insulation are poly(vinyl chloride) (PVC) compounds, polyamides, polyethylenes, polypropylenes, polyurethanes, and fluoropolymers. PVC compounds possess high dielectric and mechanical strength, flexibiUty, and resistance to flame, water, and abrasion. Polyethylene and polypropylene are used for high speed appHcations that require a low dielectric constant and low loss tangent. At low temperatures, these materials are stiff but bendable without breaking. They are also resistant to moisture, chemical attack, heat, and abrasion. Table 14 gives the mechanical and electrical properties of materials used for cable insulation. 

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. 

Poly(vinyl chloride). PVC is one of the most important and versatile commodity polymers (Table 4). It is inherently flame retardant and chemically resistant and has found numerous and varied appHcations, principally because of its low price and capacity for being modified. Without modification, processibiUty, heat stabiUty, impact strength, and appearance all are poor. Thermal stabilizers, lubricants, plasticizers, impact modifiers, and other additives transform PVC into a very versatile polymer (257,258). 

There are numerous misconceptions about the sources of various chemical elements in waste, particularly those that are potential acid formers when the waste is incinerated or mechanically converted and used as a refuse-derived fuel. For example, it is often mistakenly stated that the source of chlorine in waste, hence a potential source of HCl emissions, is poly(vinyl chloride). The relative contents of selected, potentially acid-forming elements in the organic portion of a sample of waste collected from various households in one U.S. East Coast city is given in Table 2 (17). In this city, a chief source of chlorine in the waste is NaCl, probably from food waste. 

The physical properties of vinyl chloride are Hsted in Table 1 (12). Vinyl chloride and water [7732-18-5] are nearly immiscible. The equiUbrium concentration of vinyl chloride at 1 atm partial pressure in water is 0.276 wt % at 25°C, whereas the solubiUty of water in vinyl chloride is 0.0983 wt % at 25°C and saturated pressure (13). Vinyl chloride is soluble in hydrocarbons, oil, alcohol, chlorinated solvents, and most common organic Hquids. 

In a typical balanced plant producing vinyl chloride from EDC, all the HCl produced in EDC pyrolysis is used as the feed for oxychlorination. On this basis, EDC production is about evenly spHt between direct chlorination and oxychlorination, and there is no net production or consumption of HCl. The three principal operating steps used in the balanced process for ethylene-based vinyl chloride production are shown in the block flow diagram in Eigure 1, and a schematic of the overall process for a conventional plant is shown in Eigure 2 (76). A typical material balance for this process is given in Table 2. 

Table 2. Typical Material Balance for Vinyl Chloride Production by the Air-Based Balanced Ethylene Process...

Table 5. World Wide Vinyl Chloride Capacity as of January 1997 ...

Polymerization-grade vinyl chloride should not contain more than the amounts of impurities Hsted in Table 6 (145). 

Table 6. Typical Impurity Levels in Monomer Grade Vinyl Chloride ...

GopolymeriZation. The importance of VDC as a monomer results from its abiHty to copolymerize with other vinyl monomers. Its Rvalue equals 0.22 and its e value equals 0.36. It most easily copolymerizes with acrylates, but it also reacts, more slowly, with other monomers, eg, styrene, that form highly resonance-stabiHzed radicals. Reactivity ratios (r and r, with various monomers are Hsted in Table 2. Many other copolymers have been prepared from monomers for which the reactivity ratios are not known. The commercially important copolymers include those with vinyl chloride (VC),... 

The properties of PVDC (Table 3) ate usually modified by copolymerization. Copolymers of high VDC content have lower melting temperatures than PVDC. Copolymers containing mote than mol % acrylate or methacrylate ate amorphous. Substantially mote acrylonitrile (25%) or vinyl chloride (45%) is required to destroy crystallinity completely. 

Table 2. Summary of Poly(vinyl chloride) Morphology...

---