Chlorine content

Epoxy resins will contain some hydrolyzable or active chlorine depending on the completion of the epichlorohydrin reaction. It may also contain less active chlorine via chlorinated groups along the polymeric chain. Hydrolyzable chlorine may be determined by ASTM D 1726 and total chlorine by ASTM D 1847. 

The active chlorine is capable, under certain conditions, of blocking reactions with Lewis base catalysts. The main effect of high chlorine content is to reduce system reactivity and crosslink density. Chlorine may also cause corrosion of delicate substrates. Chlorine content is a common test for epoxy resins in the electrical and electronic industries. 

---

Based on 70% chlorine content. For chlorinated paraffins having lower chlorine content, the use level must be raised accordingly. 

Cblorina.ted Pa.ra.ffins, The term chlotinated paraffins covers a variety of compositions. The prime variables are molecular weight of the starting paraffin and the chlorine content of the final product. Typical products contain from 12—24 carbons and from 40—70 wt % chlorine. Liquid chlotinated paraffins are used as plasticizers (qv) and flame retardants ia paint (qv) and PVC formulations. The soHd materials are used as additive flame retardants ia a variety of thermoplastics. In this use, they are combiaed with antimony oxide which acts as a synergist. Thermal stabilizers, such as those used ia PVC (see vinyl polymers), must be used to overcome the inherent thermal iastabiUty. 

Tetrachlorphthalic Anhydride and Tetrachlorphthalic Acid. Tetrachlorphthalic anhydride [117-08-8] (TCPA) is manufactured by the ferric chloride catalyzed chlorination of phthalic anhydride. The relatively low chlorine content and the lower flame retardant efficiency of the aromatic chlorides limit use to unsaturated polyester resin formulations that do not requite a high degree of flame retardancy. 

The chemical analysis of waste fuels also demonstrates that the wood-based fuels contain virtually no sulfur and Htde nitrogen. Unless the hog fuel contains bark from logs previously stored ia salt-water, the chlorine content is very modest to nonmeasurable. 

Chlorine can be removed by either activated carbon adsorption or by reaction with olefins such as ethylene over-activated carbon at temperatures of 30—200°C (44). Addition of Hquid high boiling paraffins can reduce the chlorine content in the HCl gas to less than 0.01% (45). 

The majority of secondary plasticizers ia use are chlotinated paraffins, which are hydrocarbons chlotinated to a level of 30—70%. Eor a given hydrocarbon chain, viscosity iacreases with chlorine content, as does the fire retardancy imparted to the formulation. These materials aid fire retardancy due to thein chlorine content. Chlotinated paraffins of the same chlorine content may, however, have different volatiHties and viscosities if they are based on different hydrocarbon chaias (see Cm OROCARBONS and cm OROHYDROCARBONS, cm.ORiNATDD paraffins). 

Chlorinated Polyethylene. Chlorinating polyethylene under pressure results in a polymer having a chlorine content varying from 25 to 42%. The polymer requires the incorporation of carbon black and minerals for achieving good physical properties. The polymers handle like conventional polymers and can be mixed and processed on conventional mbber equipment. 

Neoprene latex type Comonomer Emulsifiers Chlorine content, wt % pH at 25° C Standard soHds, wt % Distinguishing features Primary appHcations... 

K. L. Chumey, A. E. Ledford, S. S. Bmce, and E. S. Domalski, The Chlorine Content of Municipal Solid Waste from Baltimore County, May land and Brooklyn, New York, National Bureau of Standards, Gaithersburg, Md., Apr. 1985. 

In solutions, the concentration of available chlorine in the form of hypochlorite or hypochlorous acid is called free-available chlorine. The available chlorine in the form of undissociated A/-chloro compounds is called combined-available chlorine. Several analytical methods can be used to distinguish between free- and combined-available chlorine (8). Bleaches that do not form hypochlorite in solution like chlorine dioxide and nonchlorine bleaches can be characterized by thek equivalent available chlorine content. This can be calculated from equation 5 by substituting the number of electrons accepted divided by two for the number of active chlorine atoms. It can also be measured by iodomettic titration. 

Calcium Hypochlorite. High assay calcium hypochlorite [7778-54-3] was first commercialized in the United States in 1928 by Mathieson Alkali Works, Inc. (now Olin Corp.) under the trade name HTH. It is now produced by two additional manufacturers in North America (Table 5). Historically, it usually contained about 1% water and 70—74% av CI2, so-called anhydrous product, but in 1970, a hydrated product was introduced (234). It is similar in composition to anhydrous Ca(OCl)2 except for its higher water content of about 6—12% and a slightly lower available chlorine content. This product has improved resistance to accidental initiation of self-sustained decomposition by a Ht match, a Ht cigarette, or a small amount of organic contamination. U.S. production in the 1990s consists primarily of partially hydrated Ca(OCl)2, which is sold as a 65% av CI2 product mainly for swimming pool use. Calcium hypochlorite is also sold as a 50% av CI2 product as a sanitizer used by dairy and food industries and in the home, and as a 32% product for mildew control. 

Sulfur Dioxide Reductant. The Mathieson process uses sulfur dioxide, sodium chlorate, and sulfuric acid to produce chlorine dioxide gas with a much lower chlorine content. The sulfur dioxide gas reductant is oxidized to make sulfuric acid, reducing the overall acid requirement of the process. Air is used to dilute the chlorine dioxide produced by this process. The exit gases flow through a scmbber to which chlorate is added in order to remove any unreacted sulfur dioxide. Spent Hquor, containing some unreacted chlorate, sulfuric acid, and sodium sulfate, continuously overflows from this process. 

Progressive chlorination of a hydrocarbon molecule yields a succession of Hquids and/or soHds of increasing nonflammability, density, and viscosity, as well as improved solubiUty for a large number of inorganic and organic materials. Other physical properties such as specific heat, dielectric constant, and water solubihty decrease with increasing chlorine content. 

AH volatile organic solvents are toxic to some degree. Excessive vapor inhalation of the volatile chloriaated solveats, and the central nervous system depression that results, is the greatest hazard for iadustrial use of these solvents. Proper protective equipment and operating procedures permit safe use of solvents such as methylene chloride, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene ia both cold and hot metal-cleaning operations. The toxicity of a solvent cannot be predicted from its chlorine content or chemical stmcture. For example, 1,1,1-trichloroethane is one of the least toxic metal-cleaning solvents and has a recommended threshold limit value (TLV) of 350 ppm. However, the 1,1,2-trichloroethane isomer is one of the more toxic chloriaated hydrocarboas, with a TLV of only 10 ppm. 

The principal feedstocks used today are the normal paraffin fractions CIO—C13, C12—C14, C14—C17, and C18—C20 together with paraffin wax fractions of C24—C30, precise compositions may vary depending on petroleum oil source. Chlorination extent generally varies from 30 to 70% by weight. The choice of paraffinic feedstock and chlorine content is dependent on the appHcation. 

By virtue of the nature of the paraffinic feedstocks readily available, commercial chlorinated paraffins are mixtures rather than single substances. The degree of chlorination is a matter of judgment by the manufacturers on the basis of their perception of market requirements as a result, chlorine contents may vary from one manufacturer to another. However, customers purchasing requirements often demand equivalent products from different suppHers and hence similar products are widely available. 

The physical and chemical properties of chlorinated paraffins are deteanined by the carbon chain length of the paraffin and the chlorine content. This is most readily seen with respect to viscosity (Fig. 1) and volatiUty (Fig. 2) increasing carbon chain length and increasing chlorine content lead to an increase in viscosity but a reduction in volatiUty. 

Paraffin carbon chain length Nominal chlorine contents, %w / w Color hazen (APHA) Viscosity, mPa-s (=cP) Density, g/mL Thermal stability, %w/wHCl Volatihty, %w/w Refractive index... 

Toxicity. The acute toxicity of chlotinated paraffins has been tested ia a range of animals and was found to be very low (4). A comprehensive study (5) demonstrated that the toxicity of chlotinated paraffins was related to carbon chain length and to a lesser degree chlorine content. The shorter chain-length chlotinated paraffins were more toxic than the longer chain chlotinated paraffins. 

Environmental. In general, chlorinated paraffins biodegrade the rate is determined by chlorine content and carbon chain length. Microorganisms previously acclimatized to specific chlorinated paraffins show a greater ability to degrade the compounds than nonacclimatized organisms. Mammals and fish have been shown to metabolize chlorinated paraffins (8). 

The side-chain chlorine contents of benzyl chloride, benzal chloride, and benzotrichlorides are determined by hydrolysis with methanolic sodium hydroxide followed by titration with silver nitrate. Total chlorine determination, including ring chlorine, is made by standard combustion methods (55). Several procedures for the gas chromatographic analysis of chlorotoluene mixtures have been described (56,57). Proton and nuclear magnetic resonance shifts, characteristic iafrared absorption bands, and principal mass spectral peaks have been summarized including sources of reference spectra (58). Procedures for measuring trace benzyl chloride ia air (59) and ia water (60) have been described. 

Polychloiinated naphthalenes (PCNs) are halogenated aiomatic hydiocaibons that are no longer produced. They can be synthesized by the chlorination of naphthalene. The commercial products were graded and sold according to their chlorine content (wt %), and used as waxes and impregnants (for... 

CSM grade Chlorine content. Sulfur content, % Mooney Principal use... 

---