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US 5,475,163 AGranted
Process for the preparation of 2,3-dichloro-nitrobenzene
AssigneeBayer Aktiengesellschaft
InventorsKarl H. Neumann, Wolfram Kissener, Helmut Fiege
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Abstract
2,3-dichloro-nitrobenzene can be prepared by nitration of 1,2-dichlorobenzene using an anhydrous mixture of phosphoric acid, sulphuric acid and nitric acid. The conditions according to the invention displace the ratio of 2,3,-dichloro-nitrobenzene and 3,4-dichloro-nitrobenzene in favor of the 2,3-isomer.
Claims9
A process for the preparation of 2,3-dichloro-nitrobenzene by nitration of 1,2-dichlorobenzene with nitric acid, wherein an anhydrous mixture of phosphoric acid, sulphuric acid and nitric acid is employed for the nitration;
- the molar mixing ratio of sulphuric acid and phosphoric acid assumes values from 0.05 to 3 mol of H.sub.2 SO.sub.4 :1 mol of H.sub.3 PO.sub.4 ;
- the nitration is carried out at a reaction temperature of 30.degree. to 180.degree. C.;
- and the nitric acid is employed in a molar ratio of 0.7 to 1.4, relative to the 1 mol of 1,2-dichloro-benzene.
Dependencies are inferred from the claim text.