1,3-Dichlorobenzene organic compounds

The oxidation of organic compounds by water-soluble inorganic oxidants is often made difficult not only by the insolubility of the organic substrate in water, but also by the susceptibility of many of the miscible non-aqueous solvents to oxidation. Solubilization of the ionic oxidant into solvents such as benzene, chloroform, dichloromethane or 1,2-dichlorobenzene, by phase-transfer catalysts obviates these problems, although it has been suggested that dichloromethane should not be used, as it is also susceptible to oxidation [1]. 

This includes bioremediation cases of contaminated sites with several toxic and carcinogenic pollutants, such as petroleum hydrocarbons, PAHs, dichlorobenzene, chlorinated hydrocarbons, carbon tetrachloride, Dicamba, methyl bromide, trinitrotoluene, silicon-based organic compounds, dioxins, alkyl-phenol polyethoxylates, nonylphenol ethoxylates, and polychlorinated biphenyls. The following is a brief summary of each case. 

No studies were located regarding the tissue distribution of 1,4-dichlorobenzene in humans after inhalation exposure to 1,4-dichlorobenzene. The compound has been found, however, in human blood, fatty tissue, and breast milk, presumably as a result of exposure via inhalation. In a study of Tokyo residents, detectable levels of 1,4-dichlorobenzene were found in all of 34 adipose tissue samples and all of 16 blood samples tested (Morita and Ohi 1975 Morita et al. 1975). In a national survey of various volatile organic compounds (VOC) found in composites of human adipose tissue, samples were collected from persons living in the nine geographic areas that comprise the United States (within this survey). 

As part of the Third National Health and Nutrition Evaluation Survey (NHANES III), the Environmental Health Laboratory Sciences Division of the National Center for Environmental Health, Centers for Disease Control and Prevention, will be analyzing human blood samples for 1,4-dichlorobenzene and other volatile organic compounds. These data will give an indication of the frequency of occurrence and background levels of these compounds in the general population. 

In situ thermal extraction is a process for the removal of volatile and semivolatile organic compounds (VOCs and SVOCs) from contaminated soils and groundwater. The process primarily treats chlorinated solvents such as trichloroethylene (TCE), tetraehloroethylene (PCE), and dichlorobenzene hydrocarbons such as gasoline, diesel, and jet fuel and mixtures of these compounds. 

The EPA has conducted four major studies of actual human exposure using monitors worn by random samples of people. The results are shocking. Smoking, clothes that had been dry cleaned and hung in closets, and heated water in showers and clothes washers (i.e., chloroform from chlorinated water) are major sources of human exposure to volatile organic compounds (VOCs), all of which exceeded outdoor exposure sources by two to five times at the median exposure level. The major sources of exposure to another VOC, p-dichlorobenzene, are toilet fresheners and mothballs. Pesticide exposure stems from two main sources (1) vapors emitted by soil into homes through basements and (2) soil tracked into buildings on shoes. Major stationary and mobile sources account for only 2 to 25 percent of personal exposure to the two dozen or so VOCs and pesticides that the EPA studied (Wallace 1993, 138 Ott and Roberts 1998). 

The structures for three odoriferous organic compounds containing one or more benzene rings toluene, naphthalene, and 1,4-dichlorobenzene. 

Researchers at Phillips Petroleum Company developed a commercially viable process for the synthesis of PPS involving the polymerization of p-dichlorobenzene and a sodium sulfide source in a polar organic compound at elevated temperature and pressure. This Phillips process was patented in 1967 (18). Between 1967 and 1973, Phillips built and operated a pilot plant, established market demand, and constructed a full-scale commercial plant. In 1973, the world s first PPS plant came on-stream in Phillips facility in Borger, Texas. 

Several compounds, including many deuterated and fluoro derivatives, have been used in the published literature. These include fluorobenzene, pentafluo-robenzene, l,2-dichlorobenzene-d4, l-chloro-2-fluorobenzene, 1,4-difluoroben-zene, l,2-dichloroethane-d4, 1,4-dichlorobutane, and 2-bromo-l-chloropropane. U.S. EPA has set the tuning criteria for bromofluorobenzene and decafluorotriph-enylphosphine as tuning compounds for volatile and semivolatile organic compounds. (See Chapter 1.4)... 

Trioxane is a mast unusual chemical. It is an excellent solvent for many classes of moteriols. Concentrated aqueous solutions of trioxane have solvent properties which are not possessed by trioxane itself. Molten trioxane dissolves numerous organic compounds, such as naphthalene, urea, camphor, dichlorobenzene, etc. It Is stable in alkaline or neutral solutions, yet it is depolymerized ta formaldehyde by small amounts of strong acid or acid-farming materials, and the rate of depolymerization can be readily controlled. 

A variety of isomeric or closely related mixtures of organic compounds are often found when manufacturing chemical and pharmaceutical products. However, it is usually necessary to separate these molecules in order to obtain the expected functionality of the products. Conventional methods such as distillation, extraction and crystallization might be difficult to use since the molecules to be separated might have very close chemical and physical properties. Hydrotropes are known to be selective in the solubilization of compounds and as mentioned earlier, do not perform so generally as surfactants. It has been found that the solubility enhancement in water by adding the hydrotrope sodium xylene sulfonate (SXS) will vary for different isomers such as o- and /7-nitrochlorobenzene, as well as for o- and p-dichlorobenzene (24). In this case, the c -isomer is more soluble than the p-isomer. Higher solubilities have also been reported for aromatic compounds when compared to aliphatic and alicyclic compounds (24). This selective... 

Edmonds and HiU discovered the first commercially viable process for the synthesis of PPS in 1967 in the laboratories of Phillips Petroleum Company. The patent [8] describing the Edmonds and HiU process was issued that year and effectively prevented others from entering the business until its expiration in 1984. The process involves the reaction of a polymerizable sidfur source derived from sodium sulfide and p-dichlorobenzene in a suitable polar organic compound at elevated temperature and pressure. N-methyl-2-pyrrolidone (NMP) is the preferred polar organic compound. The Edmonds and HUl process is stUl used commercially for some products manufectured by Chevron Phillips Chemical Company LP. The essential process steps in the Edmonds and HUl process are... 

Compared with many other organic compounds, camphor, iodine, and naphthalene have relatively high vapor pressures at relatively low temperatures. For example, they have a vapor pressure of 1 mm Hg at 42,39, and 53°C, respectively. Although this vapor pressure does not seem very large, it is high enough to lead, after a time, to evaporation of the solid from an open container. Mothballs (naphthalene and 1,4-dichlorobenzene) show this behavior. When iodine stands in a closed container over a period of time, you can observe movement of crystals from one part of the container to another. 

Other organic compounds that can be used as internal standards are as follows 2,4,5,6-tetrachloro-m-xylene [150], octachloronaphthalene [135], PCNB [54], 1,2,3,4-tetra-chloronaphthalene [135], 2,6-dichlorobenzonitrile [84], deuterated naphthalene [141], deuterated benzo(a)anthracene [141], l,4-dichlorobenzene-d4 [151], naphthalene-dg [151], acenaphthene-dio [151], phenanthrene-dio [151], chrysene-di2 [151] and perylene-di2, [151], and 13C-1,2,3,4-TCDD [128]. 

PEEKS can be made by two general routes. In both cases the main difficulty is to keep the crystallisable polymer in solution. Formation of the carboxyl link by polyaroylation can be carried out in liquid HF by catalysts such as BF3. The reaction is also possible in solvents such as dichlorobenzene with an excess of AICI3 both to catalyse the reaction and to solubilise the polymer by complexing with the carbonyl group in the backbone. AICI3 must then be neutralized and extracted from the polymer. The waste stream contains organic compounds, aluminium salts and hydrochloric acid. 

Several approaches are used to isolate and eoneentrate volatile analytes from waste samples for subsequent measurement. Some of these based on headspace analysis involve evaporation of volatile substanees into the space above the sample (headspace) in a closed container. Method 5021, Volatile Organic Compounds in Soils and Other Solid Matrices Using Equilibrium Headspace Analysis, is used to isolate volatile organic compounds, such as benzene, bromomethane, chloroform, 1,4-dichlorobenzene, dichloromethane, styrene, toluene, vinyl chloride, and the xylene isomers, from soil, sediment, or solid waste samples for determination by gas chromatography or gas chromatography/mass spectrometry. 

Lussier [71] has given an overview of Uniroyal Chemical s approach to the analysis of compounded elastomers (Scheme 2.2). Uncured compounds are first extracted with ethanol to remove oils for subsequent analysis, whereas cured compounds are best extracted with ETA (ethanol/toluene azeotrope). Uncured compounds are then dissolved in a low-boiling solvent (chloroform, toluene), and filler and CB are removed by filtration. When the compound is cured, extended treatment in o-dichlorobenzene (ODCB) (b.p. 180 °C) will usually suffice to dissolve enough polymer to allow its separation from filler and CB via hot filtration. Polymer identification was based on IR spectroscopy (key role), CB analysis followed ASTM D 297, filler analysis (after direct ashing at 550-600 °C in air) by means of IR, AAS and XRD. Antioxidant analysis proceeded by IR examination of the nonpolymer ethanol or ETA organic extracts. For unknown AO systems (preparative) TLC was used with IR, NMR or MS identification. Alternatively GC-MS was applied directly to the preparative TLC eluent. 

Compounds with the structure 116 carrying ethoxy or methoxy groups in D-position are prepared from o-alkoxyanilines. Not only are cyclization and condensation achieved at comparatively lower temperature, between 170 and 175°C, but the reaction also proceeds at a higher rate than for compounds with D =H. One of the above-mentioned condensation agents is similarly necessary in this case. o-Dichlorobenzene, for instance, is a suitable organic solvent. The list of solvents for condensation and cyclization also includes trichlorobenzene and nitrobenzene. The reaction conditions are not markedly affected by the type of substitution in positions A and B. 

---