Synthesis of o-nitrochlorobenzene

Preparation of o-nitrochlorobenzene

Alternative Names: o-chloronitrobenzene; o-nitrochlorobenzene; benzene, 1-chloro-2-nitro-

Nitration of chlorobenzene gives a mixture of ~33% of o-nitrochlorobenzene and ~66% of p-nitrochlorobenzene. The mixture cannot be separated by distillation alone because the boiling points are very close together. However, careful fractionation through an efficient column yields a first fraction enriched in the p-nitrochlorobenzene, and the last fraction enriched in the o-nitrochlorobenzene.

Preparation of o-nitrochlorobenzene (o-chloronitrobenzene; o-nitrochlorobenzene; benzene, 1-chloro-2-nitro-)

Preparation of o-nitrochlorobenzene (o-chloronitrobenzene; o-nitrochlorobenzene; benzene, 1-chloro-2-nitro-)

1 mole (112 g) of chlorobenzene is heated in an a round-bottomed flask to 40° C. With vigorous stirring, a mixture containing 33 ml of concentrated sulfuric acid and 45 ml of fuming nitric acid (d=1.52 g/ml) is added dropwise while the temperature is maintained between 40 and 50° C. After the addition of acid mixture the stirring is continued for an additional 2 hours, during which time the temperature of the reaction mixture drops slowly. When the reaction is complete the mixture is  poured out onto an ice and after standing for a long time, the pasty precipitate is filtered, washed with cold water, and pressed as dry as possible. The obtained mixture is carefully fractionated in vacuum, using a very efficient column. After a small forerun containing water and traces of chlorobenzene, at the temperature of about 105°/10 mm, the first fraction is collected yielding crude p-nitrochlorobenzene. A fraction of crude o-nitrochlorobenzene is collected at 110° at 10 mm. In order to fully purify the obtained fractions they are redistilled, by collecting p-nitrochlorobenzene at 105°/10 mm, and o-nitrochlorobenzene at 109.5° at 10 mm. p-Nitrochlorobenzene: m.p., 82.5°C; b.p. (corr.), 106° at 10 mm., 234° at 727 mm. o-Nitrochlorobenzene: m.p., 32.5°; b.p. (corr.), 109.5° at 10 mm., 241° at 727 mm.

The fundamental processes of dye chemistry, by H. E. Fierz-David, 90-92, 1949





InChI Key


Canonical SMILES


MeSH Synonyms

1-chloro-2-nitrobenzene, 2-chloronitrobenzene, o-chloronitrobenzene, o-nitrochlorobenzene, ONCB, ortho-chloronitrobenzene

Depositor-Supplied Synonyms

2-Chloronitrobenzene, 1-CHLORO-2-NITROBENZENE, 88-73-3, o-Chloronitrobenzene, 2-Nitrochlorobenzene, Chloronitrobenzene, o-Nitrochlorobenzene, Benzene, 1-chloro-2-nitro-, 2-Chloro-1-nitrobenzene, ONCB, Nitrochlorobenzene, Benzene, chloronitro-, Altitran, 1-Nitro-2-chlorobenzene, Mononitrochlorobenzene, Chloro-o-nitrobenzene, NSC 36934, CCRIS 141, 45926_RIEDEL, CHEBI:34270, HSDB 1322, BFCFYVKQTRLZHA-UHFFFAOYSA-N, EINECS 201-854-9, EINECS 246-695-6, Benzene, chloronitro- (mixed isomers), 25167-93-5, AI3-15385, AC-907/25014094, o-chloro-nitrobenzene, 2-chloro nitrobenzene, 2-chloro-nitrobenzene, 2-nitro chlorobenzene, 2-nitro-chlorobenzene, Nitrochlorobenzene, o-, O-Nitro chloro benzene, PubChem18481, monochloromononitrobenzene, Mononitromonochlorobenzene, ortho-nitro-chlorobenzene, 4-chloro-3-nitrobenzene, Nitrochlorobenzene, ortho, AC1L1NNG, 2-Nitro-1-chlorobenzene, DSSTox_CID_280, Nitrochlorobenzene, liquid, WLN: WNR BG, 1-Chloro-2-nitro-benzene, UNII-D1YI9R2K8O, AC1Q5AV4, 2-CNB, ACMC-1BM38, D1YI9R2K8O, DSSTox_RID_75483, DSSTox_GSID_20280, SCHEMBL78743, ghl.PD_Mitscher_leg0.936, KSC203S8J, MLS001055388, BIDD:ER0655, CHEMBL53330, 185760_ALDRICH, 25460_FLUKA, 45926_FLUKA, CTK1A3984, Chloronitrobenzene, ortho, liquid, MolPort-001-768-934, HMS3039K15, NSC36934, Tox21_200791, ANW-39150, AR-1I2076, NSC-36934, STL283954, ZINC00331636, AKOS000118963, AM87358, LS-1883, MCULE-5325741920, RP22135, RTC-063803, TRA0010661, CAS-88-73-3, NCGC00090715-01, NCGC00090715-02, NCGC00090715-03, NCGC00258345-01, 2-Chloronitrobenzene;2-Nitrochlorobenzene, AJ-19438, AK124415, AN-42443, BC203433, KB-87879, LS-29508, SC-18125, SMR000677934, ZB010566, AB1003135, DB-057100, TC-063803, ST24037930, C14407, I01-6705, Chloronitrobenzene, ortho, liquid [UN1578] [Poison], 3B3-020154, Chloronitrobenzene, ortho, liquid [UN1578] [Poison], InChI=1/C6H4ClNO2/c7-5-3-1-2-4-6(5)8(9)10/h1-4

Removed Synonyms

UN 1578 (Related), CID6945, UN1578, c0220, ML 190, 1355244-02-8, 94-48-4

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