Of o- chloronitrobenzene

Place 50 g. of o-chloronitrobenzene and 75 g. of clean dry sand in a 250 ml. flask equipped with a mechanical stirrer. Heat the mixture in an oil or fusible metal bath to 215-225° and add, during 40 minutes, 50 g. of copper bronze or, better, of activated copper bronze (Section 11,50, 4) (1), Maintain the temperature at 215-225° for a further 90 minutes and stir continuously. Pour the hot mixture into a Pyrex beaker containing 125 g. of sand and stir until small lumps are formed if the reaction mixture is allowed to cool in the flask, it will set to a hard mass, which can only be removed by breaking the flask. Break up the small lumps by powdering in a mortar, and boil them for 10 minutes with two 400 ml. 

The experimental conditions for conducting the above reaction in the presence of dimethylformamide as a solvent are as follows. In a 250 ml. three-necked flask, equipped with a reflux condenser and a tantalum wire Hershberg-type stirrer, place 20 g. of o-chloronitrobenzene and 100 ml. of diinethylform-amide (dried over anhydrous calcium sulphate). Heat the solution to reflux and add 20 g. of activated copper bronze in one portion. Heat under reflux for 4 hours, add another 20 g. portion of copper powder, and continue refluxing for a second 4-hour period. Allow to cool, pour the reaction mixture into 2 litres of water, and filter with suction. Extract the solids with three 200 ml. portions of boiling ethanol alternatively, use 300 ml. of ethanol in a Soxhlet apparatus. Isolate the 2 2- dinitrodiphenyl from the alcoholic extracts as described above the 3ueld of product, m.p. 124-125°, is 11 - 5 g. 

In a i-l. flask equipped with a mechanical stirrer are placed 200 g. (1.27 moles) of o-chloronitrobenzene and 300 g. of clean... 

B. Reduction of o-chloronitrobenzene. The stirrer is set in position carefully inside the cathode, which is clamped in place at the top. The porous cup, previously impregnated with the electrolyte, is charged with 11.5 g. (0.073 mole) of o-chloronitrobenzene (Note 5) and about 80 ml. of a mixture of acetic acid (70 ml.), concentrated sulfuric acid (22 ml.), and water (8 ml.) (Note 6). The cup is then clamped securely in position, and the beaker containing the anode is supported just clear of the bottom of the porous cup and filled with the same solution of aqueous sulfuric and acetic acids to the same level as the liquid inside the cup. The stirrer is started, the current turned on, and the system observed for a few minutes until the current has become stable. It is then adjusted at some convenient value no greater than 2 amperes. 

Stratz compared Raney Ni without inhibitor with the Raney Ni poisoned by dicy-andiamide in the hydrogenation of o-chloronitrobenzene in methanol below 120°C and 1 MPa H2. Proportion of dechlorination decreased from 44.3% without inhibitor to 0.3% in the presence of the inhibitor, and the yield of o-chloroaniline increased from 54.5% without inhibitor to 98.8% with the inhibitor. The dechlorination decreased further to 0.2%, and the yield of o-chloroaniline increased to 99.3% over a Raney Ni promoted with chromium and iron (eq. 9.50).114 Similarly, dehalogenation over the chromium- and iron-promoted Raney Ni was only 0.6% with m-chloroni-trobenzene, 0.2% with 3,4-dichloronitrobenzene, and 0.5% with p-bromonitroben-zene. 

The best general procedure for preparing 2-substituted phenox-azines is the pyrolytic condensation of o-chloronitrobenzene derivatives with sodium o-bromophenolate,20,29 followed by reduction with stannous chloride or with iron filings in acetic acid and subsequent cyclization of the ether 10. If the ether 10 is previously A-formylated,... 

A mixture of 9 g. (0.057 mole) of o-chloronitrobenzene, 12 ml. of water, 50 ml. of ethanol, and 0.5 g. of calcium chloride is heated to boiling and stirred while 10 g. of zinc dust is added slowly. Heating and stirring are continued for 10 minutes after completion of -the addition, and the mixture is then filtered. The filtrate is added to a solution of 18.5 g. of ferric chloride in 600 ml. of ice water. The precipitated product is filtered off, washed with water, and steam-distjUed,... 

A rather different cyclization process occurs when (65) is treated with tri-flooroperacctic [172] or other peracids (Scheme 2.1.26) [173]. The acylamines appear to react most cleanly, with performic acid giving yields of (68) in the range 43-91% for a wide range of compounds. The o-substituted anilides (65) are made by treatment of o-chloronitrobenzene (1 mol) with the appropriate amine (2.1 mol) followed by reduction, and acylation with formic acid, acetic anhydride or benzoyl chloride [173]. 

The doping of noble metal catalyst precursors is not restricted to the early transition metal series. Toshima has reported significant promotion of catalytic activity in the hydrogenation of acrylic acid by the addition of neodymium ions to palladium particles. Recently, Liu and coworkers have studied the influence of metal ions on the hydrogenation of o-chloronitrobenzene over platinum colloidal clusters, and the metal complex effect on the catalytic performance of metal... 

Biphenylene was observed among the products of the reaction of o-chloronitrobenzene with disodium ditelluride, and is thought to arise from benzyne dimerization. The major product, however was phenazine (102). 

In batch and continuous tests the performance of the colloidal catalyst systems has been compared to conventional Pt/C-systems. The potential of the colloidal heterogeneous catalyst lies in the possibility of fine tuning the properties for specific applications by the addition of special dopants or poisons to the precursor. The infiuence of metal ions on the hydrogenation of o-chloronitrobenzene over platinum colloids, and the effect of metal complexes on the catalytic performance of metal clusters have also been demonstrated [133-135]. 

The isomers are separated by a combination of distillation and crystallization, the lower melting point of o-chloronitrobenzene (33 °C) facilitates separation by crystallization from p-chloronitrobenzene, which melts at 83.5 °C. 

One of the uses of o-chloronitrobenzene is in the production of o-chloroaniline, which is obtained by catalytic reduction with sulfided palladium/active carbon catalysts. These catalysts enable dechlorination to be suppressed. 

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