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P-nitrotoluene Sulfonic Acid

Release time:2019-10-09 17:03:53


Product use: p-Nitrotoluene o-sulfonic acid (NTS acid) is an important industrial raw material and organic synthesis intermediate for the production of 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD acid). . DSD acid is an important intermediate in the field of fine chemicals, widely used in the field of dyes and preparation of fluorescent whitening agents, and the market demand is large.
Existing Processes and Problems: The traditional process for industrially producing NTS acid has long been produced in a tank reactor using p-nitrotoluene as a raw material and 20% fuming sulfuric acid as a sulfonating agent. Domestic production companies use this method. There are the following problems:
(1) A large amount of waste sulfuric acid by-product: about 5 tons of waste sulfuric acid to be produced per ton of NTS acid produced.
(2) The content of organic pollutants is high, handling is difficult, and it is not suitable for modern clean production requirements.
(3) The sulfonation process is a strong exothermic, and large-scale production is difficult to precisely control.
(4) The reactor type reaction process is inefficient and the degree of automation is not high.
The present technology and characteristics: the technology uses p-nitrotoluene and liquid sulfur trioxide as raw materials to prepare p-nitrotoluene o-sulfonic acid in a microstructure reactor. The reaction process is continuous, efficient and safe, and basically no waste acid is produced. Its characteristics are as follows:

method Sulfonating agent consumption / ton (100% sulfuric acid)
Amount of waste acid / ton
(acid concentration 50%)
Product purity (%) Product yield (%)
Fuming sulfuric acid method 3~3.2 6~8 96~98 95~98
Sulfur trioxide method 0.79 0 98~100 96~98