Abstract:
A method of nitrating electron-deficient carbocyclic or heterocyclic aromatic compounds such as pyridines, diazines and triazines and benzenoid aromatics having electron-withdrawing substituents involves first reacting the aromatic species with a sulphilimine species or with the corresponding N-alkali metal salt thereof to generate an N-(hetero)aryl-S,S-dialkyl, diaryl or alkylarylsulphilimine derivative. This intermediate may then be readily oxidised under relatively mild conditions using a peroxycarboxylic acid such as m-chloroperbenzoic acid, peracetic or peroxytrifluoroacetic acid. Good yields of nitrated products are obtained including some previously unprepared. The novel N-alkali(alkylaryl)sulphilimine reagents are prepared by reacting an alkali metal hydride, an alkali metal hydrogenous base or an alkyl lithium with the corresponding sulphilimine. Preferred salts are the N-lithio types and the preferred sulphilimine is diphenylsulphilimine. Where the salt is used reaction should be in an aprotic solvent but if the sulphilimine per se is the reagent a polar solvent is used.
Abstract:
The invention provides a method for the preparation of 3,4-dihydroxy-5-nitrobenzaldehyde by reacting 3-ethoxy-4-hydroxy-5-nitrobenzaldehyde with a reagent comprising zinc chloride, water and hydrogen chloride.
Abstract:
The present invention relates to a process for purifying an aromatic nitration product mixture comprising a nitrated aromatic compound, water, and nitric or sulfuric acid which comprises without regard to sequence: (a) removing at least a portion of said water from said product mixture by contacting and reacting said water in said mixture with magnesium nitrate trihydrate to form magnesium nitrate pentahydrate or magnesium nitrate hexahydrate and removing said magnesium nitrate pentahydrate or magnesium nitrate hexahydrate from said nitrated aromatic compound in said product mixture, and (b) removing at least a portion of said acid from said product mixture by contacting and reacting said acid with an ionic or non-ionic absorbent to form a reacted absorbent and removing said reacted absorbent from said nitrated aromatic compound in said product mixture.
Abstract:
La présente invention concerne des adsorbants zéolithiques à base de cristaux agglomérés de zéolithe X comprenant du baryum, du potassium et du sodium. Ces adsorbants trouvent des applications dans la séparation de coupes d'isomères aromatiques en C8 et notamment des xylènes.
Abstract:
Die vorliegende Erfindung betrifft Verfahren zur Herstellung von chemischen Produkten, bei denen der oder die Einsatzstoffe zu einem chemischen Produkt oder einer chemischen Zusammensetzung umgesetzt werden. Die vorliegende Erfindung betrifft des Weiteren Anlagen zur Durchführung solcher Verfahren, die derart ausgestaltet sind, dass während einer Unterbrechung der Verfahren kein Eintrag von mindestens einem Einsatzstoff in die Reaktion stattfindet und die nicht von einer Revisions-, Wartungs-, Reparatur- oder Reinigungsmaßnahme betroffenen Anlagenteile in sogenannter Kreislauffahrweise betrieben werden. Dadurch wird unter anderem erreicht, dass nur das betroffene Anlagenteil für die Zeit der Maßnahme stillgelegt zu werden braucht, was vorteilhaft hinsichtlich Produktivität und Wirtschaftlichkeit des Verfahrens sowie der Qualität der hergestellten Produkte sein kann. Schließlich sind Verfahren zum Betreib von Anlagen im Fall der Außerbetriebnahme einzelner Anlagenteile ein Gegenstand der Erfindung.
Abstract:
Gegenstand der Erfindung ist ein Verfahren zur Herstellung von Toluylendiamin durch Hydrierung von Dinitrotoluol in Gegenwart eines Katalysators, wobei als Ausgangsmaterial ein Dinitrotoluol eingesetzt wird, das durch Anlegen einer elektrischen Spannung behandelt wurde.
Abstract:
Proposed is a separation method in a toluene to dinitrotoluene process, wherein said method with a first process step comprising feeding a toluene comprising first stream (1) and a nitric acid comprising second stream (2) into a first reactor (R1), reacting of the toluene comprising first stream (1) and the nitric acid comprising second stream (2) within the first reactor (R1) to a first reaction mixture (3), said first reaction mixture (3) comprising a first liquid/liquid mixed phase of an acid phase and an organic phase comprising mononitrotoluene, feeding the first reaction mixture (3) into a first separation device (S1), separating the first reaction mixture (3) within the first separation device (S1) into a first forward stream (4) having a flow direction to a second process step and a first backward stream (5) having a flow direction back to the first reactor (R1), said method having a second process step comprising feeding the first forward stream (4) into a second reactor (R2), feeding a nitric acid comprising third stream (6) and a sulfuric acid comprising fourth stream (7) into the second reactor (R2), reacting of the first forward stream (4), the nitric acid comprising third stream (6) and the sulfuric acid comprising fourth stream (7) within the second reactor (R2) to a second reaction mixture (8), said second reaction mixture (8) comprising a second liquid/liquid mixed acid phase and an organic phase comprising mononitrotoluene and dinitrotoluene, feeding the second reaction mixture (8) into a second separation device (S2), separating the second reaction mixture (8) within the second separation device (S2) into a second forward stream (9) having a flow direction to a process output and a second backward stream (10) having a flow direction back to the first reactor (R1), wherein fine separating of at least one of the streams (4, 5, 9,10) after the first separation step (S1) and/or the second separation step (S2) in a coalescer is carried out.
Abstract:
Disclosed are processes and apparatuses for concentrating at least one organic acid using an alkyl acetate as an entrainer. The processes and apparatuses may use the same alkyl acetate as an entrainer to concentrate a mixture of organic acids.