Chemicals chlorobenzene

Chlorobenzene is a colorless liquid with an almond-like odor. The compound does not occur widely in nature, but is manufactured for use as a solvent (a substance used to dissolve other substances) and is used in the production of other chemicals. Chlorobenzene persists in soil (several months), in air (3.5 days), and water (less than 1 day). Additional information can be found in Chapters 3, 4, and 5. 

Chlorobenzene production has been declining since its peak in 1969, and is likely to continue declining due to the substitution of more environmentally acceptable chemicals. Chlorobenzene is produced by chlorination of benzene in the presence of a catalyst, and is produced as an end product in the reductive chlorination of di- and trichlorobenzenes. 

Similar to other volatile organic chemicals, chlorobenzene is a nervous system depressant. In addition, lesions of the liver and kidneys have also been observed following toxic doses. 

Separations based upon differences in the chemical properties of the components. Thus a mixture of toluene and anihne may be separated by extraction with dilute hydrochloric acid the aniline passes into the aqueous layer in the form of the salt, anihne hydrochloride, and may be recovered by neutralisation. Similarly, a mixture of phenol and toluene may be separated by treatment with dilute sodium hydroxide. The above examples are, of comse, simple apphcations of the fact that the various components fah into different solubihty groups (compare Section XI,5). Another example is the separation of a mixture of di-n-butyl ether and chlorobenzene concentrated sulphuric acid dissolves only the w-butyl other and it may be recovered from solution by dilution with water. With some classes of compounds, e.g., unsaturated compounds, concentrated sulphuric acid leads to polymerisation, sulphona-tion, etc., so that the original component cannot be recovered unchanged this solvent, therefore, possesses hmited apphcation. Phenols may be separated from acids (for example, o-cresol from benzoic acid) by a dilute solution of sodium bicarbonate the weakly acidic phenols (and also enols) are not converted into salts by this reagent and may be removed by ether extraction or by other means the acids pass into solution as the sodium salts and may be recovered after acidification. Aldehydes, e.g., benzaldehyde, may be separated from liquid hydrocarbons and other neutral, water-insoluble hquid compounds by shaking with a solution of sodium bisulphite the aldehyde forms a sohd bisulphite compound, which may be filtered off and decomposed with dilute acid or with sodium bicarbonate solution in order to recover the aldehyde. 

Other sources of by-product HCl include allyl chloride, chlorobenzenes, chlorinated paraffins, linear alkylbenzene, siHcone fluids and elastomers, magnesium, fluoropolymers, chlorotoluenes, benzyl chloride, potassium sulfate, and agricultural chemicals. 

Beilstein Handbook of Organic Chemistry. This reference (55) is one of the most significant collections of data in organic chemistry. The physical and chemical properties of organic compounds are tabulated in more than 500 fields. Most of these fields are searchable, and a sample of the record for chlorobenzene [108-90-7] is shown in Table 3. 

The first detailed investigation of the reaction kinetics was reported in 1984 (68). The reaction of bis(pentachlorophenyl) oxalate [1173-75-7] (PCPO) and hydrogen peroxide cataly2ed by sodium saUcylate in chlorobenzene produced chemiluminescence from diphenylamine (DPA) as a simple time—intensity profile from which a chemiluminescence decay rate constant could be determined. These studies demonstrated a first-order dependence for both PCPO and hydrogen peroxide and a zero-order dependence on the fluorescer in accord with an earher study (9). Furthermore, the chemiluminescence quantum efficiencies Qc) are dependent on the ease of oxidation of the fluorescer, an unstable, short-hved intermediate (r = 0.5 /is) serves as the chemical activator, and such a short-hved species "is not consistent with attempts to identify a relatively stable dioxetane as the intermediate" (68). 

Chemical Properties and Reactivity. LLDPE is a saturated branched hydrocarbon. The most reactive parts of LLDPE molecules are the tertiary CH bonds in branches and the double bonds at chain ends. Although LLDPE is nonreactive with both inorganic and organic acids, it can form sulfo-compounds in concentrated solutions of H2SO4 (>70%) at elevated temperatures and can also be nitrated with concentrated HNO. LLDPE is also stable in alkaline and salt solutions. At room temperature, LLDPE resins are not soluble in any known solvent (except for those fractions with the highest branching contents) at temperatures above 80—100°C, however, the resins can be dissolved in various aromatic, aUphatic, and halogenated hydrocarbons such as xylenes, tetralin, decalin, and chlorobenzenes. 

The most widely used process for the production of phenol is the cumene process developed and Hcensed in the United States by AHiedSignal (formerly AHied Chemical Corp.). Benzene is alkylated with propylene to produce cumene (isopropylbenzene), which is oxidized by air over a catalyst to produce cumene hydroperoxide (CHP). With acid catalysis, CHP undergoes controUed decomposition to produce phenol and acetone a-methylstyrene and acetophenone are the by-products (12) (see Cumene Phenol). Other commercial processes for making phenol include the Raschig process, using chlorobenzene as the starting material, and the toluene process, via a benzoic acid intermediate. In the United States, 35-40% of the phenol produced is used for phenoHc resins. 

The Dow Chemical Company started production of chlorobenzenes in 1915 (3). Chlorobenzene was the first and remained the dominant commercial product for over 50 years with large quantities being used during World War I to produce the military explosive picric acid [88-89-1]. 

The Dow Chemical Company in the mid-1920s developed two processes which consumed large quantities of chlorobenzene. In one process, chlorobenzene was hydrolyzed with ammonium hydroxide in the presence of a copper catalyst to produce aniline [62-53-3J. This process was used for more than 30 years. The other process hydrolyzed chlorobenzene with sodium hydroxide under high temperature and pressure conditions (4,5) to product phenol [108-95-2]. The LG. Earbenwerke in Germany independentiy developed an equivalent process and plants were built in several European countries after World War II. The ICI plant in England operated until its dosing in 1965. 

In the 1930s, the Raschig Co. in Germany developed a different chlorobenzene-phenol process in which steam with a calcium phosphate catalyst was used to hydrolyze chlorobenzene to produce phenol (qv) and HCl (6). The recovered HCl reacts with air and benzene over a copper catalyst (Deacon Catalyst) to produce chlorobenzene and water (7,8). In the United States, a similar process was developed by the BakeHte Division of Union Carbide Corp., which operated for many years. The Durez Co. Hcensed the Raschig process and built a plant in the United States which was later taken over by the Hooker Chemical Corp. who made significant process improvements. 

Other Chlorobenzenes. The market for the higher chlorobenzenes (higher than di) is small in comparison to the combined mono- and dichlorobenzenes. Trichlorobenzenes are used in some pesticides, as a dye carrier, in dielectric fluids, as an organic intermediate and a chemical manufacturing solvent, in lubricants, and as a heat-transfer medium. These are small and decreasing markets. 

W K. ohnson with A. Leder and Y. Sakuma, "CEH Product Review", Chlorobenzenes Chemical Economics Handbook, SRI International, Menlo Park, Calif., Oct. 1989. 

Obtain the TLVs for the following chemicals carbon tetrachloride, chlorobenzene, iodine, ethyl formate, phenol, methanol, and MEK (methyl ethyl ketone). Rank these in order of greatest health risk. Here s a chance for you to become acquainted with some of the Web sites referred to earlier. 

Chlorobenzene 0.1 0.1 Liver or kidney problems Discharge from chemical and agricultural chemical factories... 

Organic chemicals made directly from chlorine include derivatives of methane methyl chloride, methylene chloride, chloroform, carbon tetrachloride, chlorobenzene ortho- and para-dichlorobenzenes ethyl chloride, and ethylene chloride. 

A trade association of chlorobenzene producers who seek to coordinate industry efforts regarding their product. CPA is concerned with scientific, environmental, and safety issues involving these chemicals in response to federal, state, and international regulator activities. 

Phenol is also produced from chlorobenzene and from toluene via a benzoic acid intermediate (see Reactions and Chemicals from Toluene ). 

Halobenzenes without electron-withdrawing substituents don t react with nucleophiles under most conditions. At high temperature and pressure, however, even chlorobenzene can be forced to react. Chemists at the Dow Chemical Company discovered in 1928 that phenol could be prepared on a large industrial scale by treatment of chlorobenzene with dilute aqueous NaOH at 34U °C under 170 atm pressure. 

Chlorobenzene (anhydrous, 99.8%, Sure/Seal bottle) was purchased from the Aldrich Chemical Company and used as received. 

Aprotic solvents are not protogenic, but can be protophilic, e.g. acetone, 1,4-dioxan, tetrahy drof uran, dimethy If ormamide, hexamethylphos-phortriamide, propylene carbonate and sulpholane. Solvents that do not participate in protolytic reactions, i.e. do not donate or accept a proton, are usually chemically inert, such as benzene, chlorobenzene, chloroform, tetrachloromethane, etc. 

Crabtree s catalyst was obtained from Strem Chemicals. The NBR grade used throughout was Krynac 38.50 (NBR containing 38% acrylonitrile units) from Bayer Rubber Inc. Solvents employed (chlorobenzene, acetone and 2-butanone) were used as received from Fisher Chemical Co. The purity of H2 and D2 (02 free) from Linde-Union Carbide was reported to be 99.99%. 

Mackay D, Di Guardo A, Paterson S, Kicsi G, Cowan D, Kane D (1996) Assessment of chemical fate in the environment using evaluative, regional and local-scale models illustrative application to chlorobenzene and linear alkylbenzene sulfonates. Environ Toxicol Chem 15(9) 1638-1648... 

The van t Hoff equation also has been used to describe the temperature effect on Henry s law constant over a narrow range for volatile chlorinated organic chemicals (Ashworth et al. 1988) and chlorobenzenes, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons (ten Hulscher et al. 1992, Alaee et al. 1996). Henry s law constant can be expressed as the ratio of vapor pressure to solubility, i.e., pic or plx for dilute solutions. Note that since H is expressed using a volumetric concentration, it is also affected by the effect of temperature on liquid density whereas kH using mole fraction is unaffected by liquid density (Tucker and Christian 1979), thus... 

Mackay, D., Shiu, W.Y., Ma, K.C. (1992a) Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals. Vol. 1, Monoaromatic Hydrocarbons, Chlorobenzenes and PCBs. Lewis Publishers, Inc., Chelsea, Michigan. 

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