1,2,3-Trichlorobenzene

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) teti-alin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) iaopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) n-butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phth ate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

The observation of nitration in nitromethane fully dependent on the first power of the concentration of aromatic was made later. The rate of reaction of /)-dichlorobenzene ([aromatic] = 0-2 mol [HNO3] = 8-5 mol 1 ) obeyed such a law. The fact that in a similar solution 1,2,4-trichlorobenzene underwent reaction according to the same kinetic law, but about ten times slower, shows that under first-order conditions the rate of reaction depends on the reactivity of the compound. 

Randall used C-NMR to study the methylene spectrum of polystyrene. In 1,2,4-trichlorobenzene at 120°C, nine resonances were observed. These were assumed to arise from a combination of tetrads and hexads. Using m and r notation, extend Table 7.8 to include all 20 possible hexads. Criticize or defend the following proposition Assuming that none of the resonances are obscured by overlap, there is only one way that nine methylene resonances can be produced, namely, by one of the tetrads to be split into hexads while the remaining tetrads remain unsplit. 

In the hquid-phase chlorination, 1,3-dichlorobenzene is found only in a small quantity, and 1,3,5-trichlorobenzene and 1,2,3,5-tetrachlorobenzene are undetectable. The ratios of 1,4- to 1,2-dichlorobenzene with various catalysts are shown in Table 3. Iodine plus antimony trichloride is effective in selectively chlorinating 1,2,4-trichlorobenzene to 1,2,4,5-tetrachlorobenzene (22), however, 1,2,4,5-tetrachlorobenzene is of limited commercial significance. 

Dechlorination can be done in the vapor phase with palladium, platinum, copper, or nickel catalysts (23—26) or in the Hquid phase with palladium catalysts (27). The vapor-phase dechlorination of 1,2,4-trichlorobenzene is reported to give good yields of 1,3-dichlorobenzene (24,26). 

Toxicity to fish is included in the data Hsted in Table 4. Marine life, particularly fish, may suffer damage from spills in lakes and streams. The chlorobenzenes, because they are denser than water, tend to sink to the bottom and may persist in the area for a long time. However, some data indicate that dissolved 1,2,4-trichlorobenzene can be biodegraded by microorganisms from wastewater treatment plants and also has a tendency to slowly dissipate from water by volatilization (34). 

Dichlorobenzene is sold as two grades technical chlorobenzene <0.05, trichlorobenzenes <1.0, 1,2-dichlorobenzene 80, and other isomers <19.0 and purified, produced by redistilling the technical product in a very efficient stiU chlorobenzene <0.05, 1,2,4 trichlorobenzene <0.2 and 1,2-dichlorobenzene 98.0. 

Dichlorobenzene. T -Dichlorobenzene s largest and growing oudet is in the manufacture of poly(phenylene sulfide) resin (PPS). Other apphcations include room deodorant blocks and moth control, a market which is static and likely to remain unchanged but combined is currently a larger outlet than PPS. Small amounts ofT -dichlorobenzene are used in the production of 1,2,4-trichlorobenzene, dyes, and insecticide intermediates. Exports have been a principal factor in U.S. production with about 25% exported in 1988. 

In a 250-ml. flask attached to a Vigreux column 30 cm. in over-all length ("Note 1) a mixture of 42.8 g. (0.2 mole) of phenyl salicylate ( Salol, m.p. 42-43°), 26.7 g. (0.25 mole) of o-tolui-dine, and 60 g. of 1,2,4-trichlorobenzene (m.p. 15-16°), is heated at the boiling point, so that the phenol formed slowly distils. The temperature rises from 183° to 187° during the first hour, and 22-23 g. of distillate is collected. Heating is continued until the temperature rises to 202° and a total of 45-46 g. of distillate has been collected (Note 2). The flask is then removed, and to it are added 3 g. of Norite and 10 nil. of trichlorobenzene. The mixture is heated to boiling and filtered hot by suction. The... 

Trichlorobenzene [120-82-1] M 181.5, m 17 , b 210 . Separated from a mixture of isomers by washing with fuming H2SO4, then water, drying with CaS04 and slowly fractionally distilling. [Jensen, Marino and Brown J Am Chem Soc 81 3303 7959.]... 

Trichlorobenzene 0.07 0.07 Changes in adrenal glands Discharge from textile finishing factories... 

Figure 13.22 shows the resolution of the surfactants Tween 80 and SPAN. The high resolution obtained will even allow the individual unreacted ethylene oxide oligomers to be monitored. Figure 13.23 details the resolution of many species in both new and aged cooking oil. Perhaps the most unique high resolution low molecular weight SEC separation we have been able to obtain is shown in Fig. 13.24. Using 1,2,4-trichlorobenzene as the mobile phase at 145°C with a six column 500-A set in series, we were able to resolve Cg, C, Cy, Cg, C9, Cio, and so on hydrocarbons, a separation by size of only a methylene group. Individual ethylene groups were at least partially resolved out to Cjg. This type of separation should be ideal for complex wax analysis.

The reaction of methyl anthranilate and 3-amino-2-chloropyridine in 1,2,4-trichlorobenzene in the presence of KOt-Bu at 50 °C gave 5,1 l-dihydro-6//-pyrido[2,3-Z)]benzodiazepin-6-one and 6-amino-ll//-pyr-ido[2,l-Z)]quinazolin-l 1-one as a by-product (99BMCL3031). 

This compound was prepared by heating benzene-1,2-diamine (2.16 g, 20 mmol) and the appropriate derivative of diethyl malonate (10 mmol) in 1,2,4-trichlorobenzene (15 rnL) at 190—195 "C for 2 h. The resulting solution was cooled and the precipitated product was collected and washed with benzene, followed by petroleum ether.253... 

Urea (3.2 g, 53 mmol), (NH4)2Mo04 (0.126g, 0.6 mmol), and pyridine-2,3-dicarboxylic acid (l.Og, 6 mmol) were ground together until homogenous. The lnixlure was stirred in 1,2,4-trichlorohenzene (40 mL) for 1 h at 156-160=C. A ground mixture of cobalt(II) oxalate dihydrate (1.1 g, 6 mmol) and urea (2.5 g, 42 mmol) was slowly added under N2. The temperature was maintained at 205-210 C for 3.5 h. On completion, excess 1,2,4-trichlorobenzene was removed by distillation under reduced pressure. The crude product was washed with benzene (100 mL), crushed and washed successively with EtOH, warm H20, warm 5% aq NaOH, warm H20, warm 2.5% HC1, and warm H20, and dried at 80 C yield 0.882 g (45%). 

In order to reduce the rate of this reaction to a measurable value, a further study was carried out using 1,2,4-trichlorobenzene as solvent and aluminium tribromide as catalyst343. Under these conditions, isopropylation was still too fast to measure directly, and the relative rates of methylation, ethylation and isopropylation were 1 57 > 2,500. For methylation with methyl bromide,... 

EFFECT OF EXCESS AlBrj ON THE AlBr3-CATALYSED rbaction of PhCOBr WITH TOLUENE IN 1,2,4-TRICHLOROBENZENE AT 25 C415... 

Solvents. Commercially available reagent grade solvents were used without purification except as noted. 1,2,4-Trichlorobenzene was fractionally distilled and the center cut with bp 92°-93°C/16 mm was used. 

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