Process for the preparation of 4-nitrotoluene-2-sulphonic acid
AssigneeBayer Aktiengesellschaft
InventorsErnst Goldschmitt, Peter Schnegg, Heinz U. Blank
Life of this patent
Estimating the term…
Abstract
In a process for the preparation of 4-nitrotoluene-2-sulphonic acid by reacting 4-nitrotoluene with gaseous sulphur trioxide at an elevated temperature, the improvement wherein molten 4-nitrotoluene is reacted with gaseous sulphur trioxide at a temperature in the range from 60.degree. to 150.degree. C. under a pressure above the vapor pressure of 4-nitrotoluene, in a molar ratio of sulphur trioxide to 4-nitrotoluene of 0.1:1 to 1.5:1, and, after a conversion of at least 70 percent of the reaction component not employed in excess is achieved, the sulphonation mixture is treated with water.
Claims11
In a process for the preparation of 4-nitrotoluene-2-sulphonic acid by reacting 4-nitrotoluene with gaseous sulphur trioxide at an elevated temperature, the improvement wherein molten 4-nitrotoluene is reacted with undiluted gaseous sulphur trioxide or gaseous technical grade SO.sub.3 and diluted up to 50% by volume at a temperature in the range from 60.degree. to 150.degree. C. under a pressure above the vapor pressure of 4-nitrotoluene, in a molar ratio of sulphur trioxide to 4-nitrotoluene of 0.1:1 to 1.5:1, said sulphur trioxide being introduced into said molten 4-nitrotoluene and, after a conversion of at least 70 percent of the reaction component not employed in excess is achieved, the sulphonation mixture is treated with water.
Dependencies are inferred from the claim text.