Benzene → Nitrobenzene
Reaction equation
S(=O)(=O)(O)O.[N+:6]([O-:9])(O)=[O:7].[CH:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1>>[N+:6]([C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)([O-:9])=[O:7]Participants
Procedure
A preferred embodiment of the process is shown in FIG. 1. A sulfuric acid stream (11), a nitric acid stream (12) and a benzene stream (13) are fed to a reactor (1). When the nitric acid has reacted completely with the benzene in an adiabatic reaction procedure to give nitrobenzene, the reaction product (14), which is then at a temperature of about 130° C., is fed to a phase separator (2) in which the reaction product (14) decomposes into an organic phase ((15)=crude nitrobenzene, containing benzene in addition to nitrobenzene) and an aqueous phase ((16)=spent acid, containing small amounts of nitrobenzene and benzene in addition to sulfuric acid). The aqueous phase (16) containing mainly sulfuric acid is subjected to flash evaporation of water in an evaporator (3) by sudden pressure reduction (to from 60 mbar to 120 mbar; (19)=in the direction of the vacuum pump) and thus concentrated. The concentrated sulfuric acid (17) is stored in the sulfuric acid tank (4) for further use. In the concentration of the sulfuric acid there is obtained a vapour stream (18) containing water, sulfuric acid, nitrobenzene and benzene, and this vapour stream (18) is condensed in a condenser (5). The liquefied condensate (20) is separated into an organic phase and an aqueous phase in a phase separator (6), and the aqueous phase (21) is fed to washing while the organic phase is either likewise fed to washing (22) or—preferably—is combined with the crude nitrobenzene (15) via (23) to form stream (24). Stream (24)—consisting of the crude nitrobenzene from the phase separator (15) and optionally from stream (23)—is fed to an apparatus for benzene separation (7), in which benzene and water are separated off at the head (25) and a pre-purified nitrobenzene depleted of benzene is obtained as the bottom product (26), which has been freed wholly or partially of benzene. The pre-purified nitrobenzene (26) is fed to washing (8). The resulting stream of purified nitrobenzene (27) largely freed of nitrophenols and salts can optionally be heated again and freed in a distillation column (9) of water and any benzene still present, both of which are separated off at the head (28), as a result of which dried pure nitrobenzene (29) is obtained and stored in tank (10).
Sources & evidence
- ORD record
- ord-aef376dc995f491b99885e99b7a6d00d
- Source dataset
- uspto-grants-2014_05
- Patent number
- US08729309B2
Reaction notes
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