VCM See Vinyl chloride

Varnish linseed oil. See Linseed (Linum usitatissimum) oil Varnish Makers naphtha Varnish Makers and Painters naphtha. See VM P naphtha Vaseline. See Petrolatum Vaterite. See Calcium carbonate Vat red 23. See Pigment red 179 Vat red 29. See Pigment red 190 VBR. See Vinyl butadiene Vinyl bromide VC. See Vinyl chloride Vinylidene chloride monomer VCM. See Vinyl chloride... 

VCM. See Vinyl chloride VCA/AC. See Vinyl chloride/vinyl acetate copolymer... 

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). 

Ethylene Dichlonde and Vinyl Chloride. In the United States, all ethylene dichloride [107-60-2] (EDC) is produced from ethylene, either by chlorination or oxychlorination (oxyhydrochlorination). The oxychlorination process is particularly attractive to manufacturers having a supply of by-product HCl, such as from pyrolysis of EDC to vinyl chloride [75-01-4] monomer (VCM), because this by-product HCl can be fed back to the oxychlorination reactor. EDC consumption follows demand for VCM which consumed about 87% of EDC production in 1989. VCM is, in turn, used in the manufacture of PVC resins. Essentially all HCl generated during VCM production is recycled to produce precursor EDC (see Chlorocarbons and Cm OROHYDROCARBONS ViNYLPOLYAffiRS). 

Vinyl Chloride. See in Vol 3, C255-R to C256-L under Chloroethylene and Derivatives , and Vol 3, P343-R to P345 under Polymerization, Violent . The polymer is to be found in Vol 3, P354-R to P356-L under Polyvinyl Chloride . Addnl Refs on both the monomer (VCM) and the polymer (PVC) are presented next ... 

Vinyl chloride monomer (VCM) is produced from the chlorination of ethylene and pyrolysis of the resulting ethylene dichloride (EDC) in a cracking unit (see Figure 1). 

The fine structure of branched PVC is still the subject of research. Whereas the head-tail structure had been virtually a dogma of PVC-chemistry for some time, evidence for occasional head-to-head-tail-to-tail structures had been presented along with work on branching. Recent work on the structure of suspension polymers of VCM showed that the two-carbon branches that can be observed are not 2-chloro-ethyl units but rather 1,2-dichloroethyl branches. Such structures, it has been postulated, result from a head-to-head formation followed by two successive 1,2-chlorine shifts. The authors designate this as a billiard-ball pathway for the free-radical polymerization of vinyl chloride [46 see also extensive literature references therein]. 

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