O—Dichlorobenzene

From among the compounds chlorobenzene o dichlorobenzene and p dichlorobenzene choose the one that... 

At room temperature, HDPE is not soluble in any known solvent, but at a temperature above 80—100°C, most HDPE resins dissolve in some aromatic, aflphatic, and halogenated hydrocarbons. The solvents most frequently used for HDPE dissolution are xylenes, tetralin, decalin 1,2,4-trimethylbenzene, o-dichlorobenzene, and 1,2,4-ttichlorobenzene. 

Solubility and Solvent Resistance. The majority of polycarbonates are prepared in methylene chloride solution. Chloroform, i7j -l,2-dichloroethylene, yy -tetrachloroethane, and methylene chloride are the preferred solvents for polycarbonates. The polymer is soluble in chlorobenzene or o-dichlorobenzene when warm, but crystallization may occur at lower temperatures. Methylene chloride is most commonly used because of the high solubiUty of the polymer (350 g/L at 25°C), and because this solvent has low flammabiUty and toxicity. Nonhalogenated solvents include tetrahydrofuran, dioxane, pyridine, and cresols. Hydrocarbons (qv) and aUphatic alcohols, esters (see Esters, organic), or ketones (qv) do not dissolve polycarbonates. Acetone (qv) promotes rapid crystallization of the normally amorphous polymer, and causes catastrophic failure of stressed polycarbonate parts. 

With the discontinuation of some herbicides, eg, 2,4,5-trichlorophenol [39399-44-5] based on the higher chlorinated benzenes, and DDT, based on monochlorobenzene, both for ecological reasons, the production of chlorinated benzenes has been reduced to just three with large-volume appHcations of (mono)chlorobenzene, o-dichlorobenzene, and -dichlorobenzene. Monochlorobenzene remains a large-volume product, considerably larger than the other chlorobenzenes, in spite of the reduction demanded by the discontinuation of DDT. 

Nitrated monochlorobenzene is used as a building block to produce many other products. There is also some commercial nitration of o-dichlorobenzene in the United States and Western Europe. 

Dichlorobenzyl chloride (l,2-dichloro-4-chloromethylbenzene) containing some 2,3-dichlorobenzyl chloride is produced by the chloromethylation of o-dichlorobenzene ia oleum solution (73). Chlorination of 2-chloro-6-nitrotoluene at 160—185°C gives a mixture of 2,6-disubstituted benzal chloride and 2,6-dichlorobenzyl chloride (74). 

Dichloro-1 -nitroethane o-Dichlorobenzene p-Dichlorobenzene 3,3 -Dichlorobenzidine Dichlorodifluoromethane (Refrigerant 12)... 

The original compound, maleimide (2,5-dioxo-A -pyrroline), is synthesized by the cyclo-condensation of ammonia and maleic acid. Similarly, primary amine is added to maleic anhydride, followed by cyclocondensation, to form N-substituted maleimide (Fig. 2). This reaction is applied to the preparation of bis-maleimides (BMl) [1]. At first, BMI was used as a crosslinking agent for natural rubber (NR). An o-dichlorobenzene solution of NR was crosslinked by BMI at I08-150°C in the presence of peroxides. The radicals generated from peroxides react with the double bonds of both BMI and NR [ 1 ]. 

All H type analytical columns are supplied containing tetrahydrofuran, with the exception of GMH-HT columns, which are only shipped in o-dichlorobenzene. Semipreparative and preparative columns contain chloroform... 

Acetone Carbon tetrachloride, chloroform/o-chlorophenol, chloroform// -cresol, chloroform/hexafluoroisopropanol, chloroform/methanol (up to 60%), o-dichlorobenzene, dimethylformamide, dimethyl sulfoxide, dioxane, ethylacetate, FC-113, haxane, methylethylketone, N-methylpyrrolidone, pyridine, quinoline, cyclohexane, dodecane... 

Generally, conversion from one solvent to another is carried out at low flow rates. The commonly used flow rate for this conversion is 0.2 ml/min for standard columns and 0.1 ml/min for solvent-efficient columns. This minimizes any swelling/shrinking stress put on the column. The temperature of a solvent conversion is chosen to minimize any pressure stress on the column bank. As a general rule, the pressure per column should never exceed 3.5 MPa (500 psi) during solvent conversion. For example, the conversion of a column bank from toluene to trichlorobenzene (TCB) or o-dichlorobenzene (ODCB) is commonly carried out at 90°C. This minimizes the stress on the column due to the higher viscosity of the target solvents. 

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