摘要:
A process for preparing tolylenediamine by hydrogenating dinitrotoluene with hydrogen in the presence of a suspended catalyst in a vertically upright reactor (1), at the upper end of which is arranged a motive jet nozzle (2) through which the reaction mixture drawn off from the reactor bottom, via an external loop, is sprayed into the upper region of the reactor (1) and then flows into a central inserted tube (4) which is arranged in the longitudinal direction of the reactor, flows through the latter from the top downward and flows upward again outside the inserted tube (4) in an internal loop motion, with a heat exchanger (6) in the interior of the reactor (1), through which cooling water flows, and absorbs some of the heat of reaction as it does so, with a feed for the dinitrotoluene at the upper end of the reactor (1) and a feed for the hydrogen at the lower end of the reactor (1), and wherein, in addition to the heat exchanger (6) arranged in the interior of the reactor (1), a further heat exchanger (W) is used in the external loop, in which water absorbs the rest of the heat of reaction by indirect heat exchange with the reaction mixture, which comprises utilizing the heat of reaction to raise steam with a pressure of at least 4 bar gauge by performing the hydrogenation of dinitrotoluene to tolylenediamine at a temperature of ≧180° C.
摘要:
A process for preparing tolylenediamine by hydrogenating dinitrotoluene with hydrogen in the presence of a suspended catalyst in a vertically upright reactor (1), at the upper end of which is arranged a motive jet nozzle (2) through which the reaction mixture drawn off from the reactor bottom, via an external loop, is sprayed into the upper region of the reactor (1) and then flows into a central inserted tube (4) which is arranged in the longitudinal direction of the reactor, flows through the latter from the top downward and flows upward again outside the inserted tube (4) in an internal loop motion, with a heat exchanger (6) in the interior of the reactor (1), through which cooling water flows, and absorbs some of the heat of reaction as it does so, with a feed for the dinitrotoluene at the upper end of the reactor (1) and a feed for the hydrogen at the lower end of the reactor (1), and wherein, in addition to the heat exchanger (6) arranged in the interior of the reactor (1), a further heat exchanger (W) is used in the external loop, in which water absorbs the rest of the heat of reaction by indirect heat exchange with the reaction mixture, which comprises utilizing the heat of reaction to raise steam with a pressure of at least 4 bar gauge by performing the hydrogenation of dinitrotoluene to tolylenediamine at a temperature of ≧180° C.
摘要:
The invention relates to a process for distillatively preparing TDA from a reactant stream comprising TDA, high boilers and low boilers in a dividing wall column in which a dividing wall is disposed in the longitudinal direction of the column to form an upper combined column region (2), a lower combined column region (3), a feed section (4) having a rectifying section (5) and stripping section (6), and also a withdrawal section (7) having a rectifying section (9) and stripping section (8), which comprises the following steps: a. feeding the reactant stream (13) into the feed section (4) of the dividing wall column (1); b. drawing off a low boiler fraction via the top of the column (11); c. drawing off TDA via a side draw (14) in the withdrawal section (7) of the dividing wall column (1); d. drawing off a low boiler fraction via the bottom of the column (12).
摘要:
The invention relates to a process for distillatively preparing TDA from a reactant stream comprising TDA, high boilers and low boilers in a dividing wall column in which a dividing wall is disposed in the longitudinal direction of the column to form an upper combined column region (2), a lower combined column region (3), a feed section (4) having a rectifying section (5) and stripping section (6), and also a withdrawal section (7) having a rectifying section (9) and stripping section (8), which comprises the following steps: a. feeding the reactant stream (13) into the feed section (4) of the dividing wall column (1); b. drawing off a low boiler fraction via the top of the column (11); c. drawing off TDA via a side draw (14) in the withdrawal section (7) of the dividing wall column (1); d. drawing off a low boiler fraction via the bottom of the column (12).
摘要:
The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, if appropriate in the presence of at least one inert medium, in which the amine and the phosgene are first mixed in a mixing chamber (1) to give a reaction mixture and the reaction mixture is fed to a reactor, the amine being added through an orifice (3) arranged coaxially to the mixing chamber (1) and the phosgene being added through feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1), or the phosgene being added through the orifice (3) arranged coaxially to the mixing chamber and the amine through the feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1). At least one plane (9) is arranged upstream and at least one plane (7) downstream of the orifice (3) arranged coaxially to the mixing chamber (1) in main flow direction of the reaction mixture. The mean residence time of the reaction mixture in the mixing chamber (1) is not more than 20 ms.
摘要:
The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, if appropriate in the presence of at least one inert medium, in which the amine and the phosgene are first mixed in a mixing chamber (1) to give a reaction mixture and the reaction mixture is fed to a reactor, the amine being added through an orifice (3) arranged coaxially to the mixing chamber (1) and the phosgene being added through feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1), or the phosgene being added through the orifice (3) arranged coaxially to the mixing chamber and the amine through the feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1). At least one plane (9) is arranged upstream and at least one plane (7) downstream of the orifice (3) arranged coaxially to the mixing chamber (1) in main flow direction of the reaction mixture. The mean residence time of the reaction mixture in the mixing chamber (1) is not more than 20 ms.
摘要:
An oxidic composition which is suitable as a catalyst having divalent and trivalent iron in an atomic ratio of divalent to trivalent iron in the range from greater than 0.5 to 5.5 and oxygen as a counterion to the divalent and trivalent iron. The catalyst composition is useful in the hydrogenation of nitriles to amines.
摘要:
A process is provided for the preparation of cyclic lactams of formula (II): in which n and m can each have the values 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 and the sum of n+m is at least 3, preferably at least 4, and R1 and R2 are C1-C6-alkyl, C5-C7-cycloalkyl or C6-C12-aryl groups, by reacting a compound (I) of the formula in which R1, R2, m and n are as defined above and R are [sic] nitrile, carboxamide and carboxylic acid groups, with steam in the gas phase.
摘要:
Process for preparing isocyanates by phosgenation of amines, wherein phosgene and amine are brought into contact in at least 2 mixing chambers connected in parallel.
摘要:
Process for preparing isocyanates by phosgenation of amines, wherein phosgene and amine are brought into contact in at least 2 mixing chambers connected in parallel.