Abstract:
In einem Verfahren zur Aufarbeitung von Mischsäure und Abwasser aus der Nitrierung von Aromaten, bei dem die enthaltene Salpetersäure durch Reaktion mit einem Aromaten unter adiabatischen Bedingungen umgesetzt wird, wird a. mindestens eine Abfallstromkomponente ausgewählt aus bei der Nitrierung anfallender Abfallsäure (Mischsäure), saurem Waschwasser aus der Aufarbeitung von Rohnitroaromaten und dünner Salpetersäure, die bei einer Abgasbehandlung im Verlauf der Nitrierung anfällt, bereitgestellt, b. die mindestens eine Abfallstromkomponente mit rückkonzentrierter Schwefelsäure gemischt, c. ein Aromat in stöchiometrischem Überschuss bezogen auf die Salpetersäure in die Mischung eindosiert, d. die erhaltene Reaktionsmischung in einem adiabatisch betriebenen Reaktor umgesetzt, e. in einem Separator die erhaltene organische Phase von der schwefelsauren Phase getrennt, f. die schwefelsaure Phase im Vakuum aufkonzentriert, und g. zumindest ein Teilstrom der rückkonzentrierten Schwefelsäure aus Schritt g) in Schritt b) eingesetzt.
Abstract:
An object of the present invention is to provide an optically active bicyclic γ-amino acid derivative in a high purity. The object can be attained by a mixture of compounds represented by the general formulas (I) and (I'), or a method for producing a compound represented by the general formula (VII) or a salt thereof via the compound (I):
wherein R 1 and R 2 each represent a C1-6 alkyl group or the like; and R 3 represents a cyano group or the like,
Abstract translation:本发明的目的是提供高纯度的光学活性双环-3-氨基酸衍生物。 该目的可以通过由通式(I)和(I')表示的化合物的混合物,或通过化合物(I)制备由通式(VII)表示的化合物或其盐的方法: 其中R 1和R 2各自表示C 1-6烷基等; R 3表示氰基等,
Abstract:
The invention relates to a method for purifying crude aromatic nitro compounds produced by the nitration of aromatic compounds, said method comprising performing the following washing stage (a) one or more times: (a) bringing the crude aromatic nitro compound (N-ein) into contact with an aqueous phase (W-res) and subsequent phase separation, maintaining an organic phase (N-res) and an aqueous phase (W-res), at least one demulgator (D) being present in one or more of the washing stages (a).
Abstract:
A method and apparatus for removing non-aromatic impurities from non- nitrated aromatic reactant in a nitration production process, in which process an aromatic reactant is nitrated (100) to produce a nitrated aromatic product using a molar excess of the aromatic reactant, and non-nitrated aromatic reactant is recovered (102) from the produced nitrated aromatic product and is recycled (104) for use in the nitration production process. A portion of the removed excess non-nitrated aromatic reactant is diverted (106) and subjected to nitration (108). The nitrated stream may be further processed by separating out the spent acids (1 10) and the non-aromatic impurities (116). These streams may be sent (114, 118) to a suitable location in the nitration production train.
Abstract:
A method of removing alkalinity and salt from a nitroaromatic product downstream of water washing to remove mineral acids and alkaline washing to remove salts of organic acids, comprises washing the product stream with an acidic aqueous solution, prior to the step of removing excess organic reactant, by steam stripping or distillation. Acid removed from the stripper or column is recycled back for use in the acidic washing. The acidic washing is done instead of the neutral washing step of the prior art. It removes residual salt and decreases the level of entrained colloidal water in the nitroaromatic product.
Abstract:
A process for the removal by distillation of dinitrotoluene from process wastewater from the preparation of dinitrotoluene by nitration of toluene by means of nitrating acid, which is characterized in that the process wastewater is brought to a pH of > 8.5, fed into a stripping column in the upper region thereof and stripped in countercurrent with steam to give a vapour stream which is laden with dinitrotoluene and a bottom stream which is depleted in dinitrotoluene compared to the process wastewater used, is proposed.