106-47-8

p-Chloroaniline, 1-amino-4- chlorobenzene,is a white to light amber, crystalline solid at room temperature. It is used as an intermediate for pesticides, pharmaceuticals, pigments, and dyes. Production is similar to that of m-chloroaniline .

4-Chloroaniline is a colourless to slightly amber-coloured crystalline solid with a mild aromatic odour. It is Soluble in hot water and organic solvents. 4-Chloroaniline has a moderate vapour pressure and n-octanol/ water partition coefficient. It decomposes in the presence of light and air and at elevated temperatures.

Yellowish-white solid with a mild, sweetish odor. Odor threshold concentration is 287 ppm (quoted, Keith and Walters, 1992).

4-Chloroaniline is an important building block used in the chemical industry for the production of drugs and dyestuffs. Some benzodiazepine drugs use 4-chloroaniline in their manufacture.

ChEBI: 4-chloroaniline is a chloroaniline in which the chloro atom is para to the aniline amino group. It is a chloroaniline and a member of monochlorobenzenes.

synthesis of 4-Chloroaniline: p-chloronitrobenzene is used as raw material, Raney nickel is used as catalyst, ethanol is used as solvent, reaction temperature is 50～70°C , hydrogenation pressure is 3.04～3.55MPa, and medium pH=5～6 conditions, carry out Catalytic hydrogenation reaction to obtain 4-Chloroaniline.

Journal of the American Chemical Society, 99, p. 98, 1977 DOI: 10.1021/ja00443a018
Synthesis, p. 48, 1987 DOI: 10.1055/s-1987-27838

P-chloroaniline appears as a white or pale yellow solid. Melting point 69.5°C.

Insoluble in cold water. Soluble in hot water [Hawley].

4-Chloroaniline(106-47-8) is incompatible with oxidizing agents. Also incompatible with acids, acid chlorides, acid anhydrides and chloroformates. Subject to exothermic decomposition during high-temperature distillation. Incompatible with nitrous acid.

Toxic by inhalation and ingestion. Possible carcinogen.

Inhalation or ingestion causes bluish tint to fingernails, lips, and ears indicative of cyanosis; headache, drowsiness, and nausea, followed by unconsciousness. Liquid can be absorbed through skin and cause similar symptoms. Contact with eyes causes irritation.

Special Hazards of Combustion Products: Irritating and toxic hydrogen chloride and oxides of nitrogen may form in fires.

Flammable

Biological. In an anaerobic medium, the bacteria of the Paracoccus sp. converted 4- chloroaniline to 1,3-bis(p-chlorophenyl)triazene and 4-chloroacetanilide with product yields of 80 and 5%, respectively (Minard et al., 1977). In a field experiment, [¹⁴C]4-chloroaniline was applied to a soil at a depth of 10 cm. After 20 wk, 32.4% of the applied amount was recovered in soil. Metabolites identified include 4-chloroformanilide, 4-chloroacetanilide, 4-chloronitrobenzene, 4- chloronitrosobenzene, 4,4′-dichloroazoxybenzene, and 4,4′-dichloroazobenzene (Freitag et al., 1984).
Soil. 4-Chloroaniline covalently bonds with humates in soils to form quinoidal structures followed by oxidation to yield a nitrogen-substituted quinoid ring. A reaction half-life of 13 min was determined with one humic compound (Parris, 1980). Catechol, a humic acid monomer, reacted with 4-chloroaniline yielding 4,5-bis(4-chlorophenylamino)-3,5-cyclohexadiene-1,2-dione (Adrian et al., 1989).
Photolytic. Under artificial sunlight, river water containing 2–5 ppm 4-chloroaniline photodegraded to 4-aminophenol and unidentified polymers (Mansour et al., 1989). Photooxidation of 4-chloroaniline (100 μM) in air-saturated water using UV light (λ >290 nm) produced 4-chloronitrobenzene and 4-chloronitrosobenzene. About 6 h later, 4-chloroaniline completely reacted leaving dark purple condensation products (Miller and Crosby, 1983). In a similar study, irradiation of an aqueous solution in the range of 290–350 nm resulted in the formation of the intermediate 4-iminocyclohexa-2,5-dienylidene (Othmen et al., 2000). A carbon dioxide yield of 27.7% was achieved when 4-chloroaniline adsorbed on silica gel was irradiated with light (λ >290 nm) for 17 h (Freitag et al., 1985).
A rate constant of 8.3 x 10^-11 cm³/molecule?sec was reported for the gas-phase reaction of 4- chloroaniline and OH radicals in air (Wahner and Zetzsch, 1983).
Chemical/Physical. 4-Chloroaniline will not hydrolyze to any reasonable extent (Kollig, 1993).
Pizzigallo et al. (1998) investigated the reaction of 4-chloroaniline with ferric oxide and two forms of manganese dioxide [birnessite (δ-MnO2) and pyrolusite (MnO2)] within the pH range of 4–8 at 25 °C. The reaction rate of 4-chloroaniline was in the order birnessite > pyrolusite > ferric oxide. At pH 4.0, the reaction with birnessite was so rapid that the reaction could not be determined. Half-lives for the reaction of 4-chloroaniline with pyrolusite and ferric oxide were 383 and 746 min, respectively. The reaction rate decreased as the pH was increased. The only oxidation compounds identified by GC/MS were 4,4′-dichloroazobenzene and 4-chloro-4′- hydroxydiphenylamine.

Crystallise the aniline from MeOH, pet ether (b 30-60o), or 50% aqueous EtOH, then *benzene/pet ether (b 60-70o), and then dry it in a vacuum desiccator. It can be distilled under vacuum (b 75-77o/3mm). It sublimes in a very high vacuum. The acetate crystallises from aqueous MeOH (m 178o, 180o) or EtOH or AcOH (m 173-174o) and has b 331.3o/760mm. [Beilstein 12 III 1325, 12 IV 1116.]