Abstract:
A process is proposed for distillatively removing dinitrotoluene from process wastewater from the preparation of dinitrotoluene by nitrating toluene with nitrating acid, which comprises basifying the process wastewater to a pH of >8.5, feeding it to a stripping column in the upper region thereof and stripping it with steam in countercurrent to obtain a vapor stream laden with dinitrotoluene and a bottom stream depleted in dinitrotoluene compared to the process wastewater used.
Abstract:
PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing an oxime compound or a nitro compound by reacting a primary amine (with the proviso that the carbon atom to which an amino group is bound has at least one hydrogen atom) with hydrogen peroxide. SOLUTION: The method for producing the oxime compound or nitro compound comprises reacting the primary amine (with the proviso that the carbon atom to which the amino group is bound has at least the one hydrogen atom) with the hydrogen peroxide in the presence of a metal oxide catalyst. The metal oxide catalyst is prepared by reacting at least one kind selected from the group consisting of tungsten metal, molybdenum metal, a tungsten compound composed of tungsten and a group IIIb element, a group IVb element, a group Vb element or a group VIb element except oxygen and a molybdenum compound composed of molybdenum and the group IIIb element, the group IVb element, the group Vb element or the group VIb element except oxygen with the hydrogen peroxide. COPYRIGHT: (C)2004,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide a continuous isothermal process for preparing mononitrotoluene in the presence of a mixed acid component comprising a mixture of sulfuric acid and phosphoric acid with concentration of the resultant waste acid and recycling of the concentrated waste acid to the process. SOLUTION: (i) About 60-70% strength nitric acid and toluene are fed into a reactor and (ii) crude nitrotoluene is separated from the waste acid at a reactor outlet. (iii) The waste acid containing sulfuric acid, phosphoric acid and water is concentrated in a single-stage concentration to respective specific concentrations and (iv) the concentrated waste acid is recycled back to the reactor in a circuit to undergo a nitration reaction.