Adiabatic process for making mononitrobenzene

A dinitrobenzene, process technology, applied in the field of improved process for the preparation of mononitrobenzene, can solve the problems of removal and treatment of huge operating costs and capital investment

Active Publication Date: 2011-10-05
NORAM INT LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The operating costs and capital investment required to remove and dispose of these by-products are significant

Method used

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  • Adiabatic process for making mononitrobenzene
  • Adiabatic process for making mononitrobenzene
  • Adiabatic process for making mononitrobenzene

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Experimental program
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Embodiment

[0022] Eight batch nitrations were performed in an adiabatic continuous stirred reactor. From the perspective of chemical reactor theory, the reaction time in a batch stirred reactor is approximately equivalent to the reaction distance in an ideal continuous mixed plug flow reactor. Therefore, the results from these batch stirred reactor experiments will more closely represent the results of an ideal plug flow nitration reactor than the CSTR reactor. In all experiments performed, the concentration of nitric acid in the mixed acid was the same, which was less than 3% by weight nitric acid, and the strength of the sulfuric acid in the mixed acid was the same. Only the initial mixed acid temperature (that is, the temperature before the start of the nitration reaction) is different, resulting in different average reaction temperatures. At the beginning of each experiment, sulfuric acid and nitric acid were thoroughly mixed in the reactor at a controlled initial temperature. Then ...

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Abstract

An adiabatic process for making mononitrobenzene by the nitration of benzene which minimizes the formation of nitrophenols and dinitrobenzene by-products. The process uses a mixed acid having less than 3 wt% nitric acid, 55 to 80 wt% sulfuric acid, and water. The initial temperature of the mixed acid is in the range of 60 to 96 DEG C. The nitration reaction is complete in about 300 seconds and produces less than 1,200 ppm nitrophenols and less than about 80 ppm dinitrobenzene. The reaction can be carried out in a plug-flow or a stirred pot reactor, or a combination of such reactors.

Description

Technical field [0001] The invention relates to an improved process for preparing mononitrobenzene. More specifically, it relates to an adiabatic nitrification process that will minimize the formation of undesirable by-products. Background of the invention [0002] In industry, mononitrobenzene is produced using several adiabatic nitration technologies. Adiabatic nitrification was first introduced by Castner, as described in US 2,256,999. The adiabatic nitrification of benzene has replaced the previously used isothermal nitrification process with high energy consumption. [0003] In the late 1970s, Alexanderson et al. proposed to change the composition and temperature limit of Castner's adiabatic nitrification process, resulting in a commercially useful process, which is described in US 4,021,498 and US 4,091,042. US 4,021,498 describes a process for preparing mononitrobenzene using a mixed acid with nitric acid strength of 5-8.5 wt%, sulfuric acid strength of 60-70 wt%, and wat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/08
CPCC07C201/08C07C205/06B01J19/18
Inventor 塞尔吉奥 贝雷塔
Owner NORAM INT LTD
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