摘要:
The invention relates to a method for producing methylmethacrylate, comprising the steps: A) producing methacrolein and B) conversion of the methacrolein obtained in step A) into methylmethacrylate in an oxidative esterification reaction, characterized in that the two steps A) and B) are carried out in liquid phase at a pressure of 2 to 100 bar and step B) is carried out in the presence of a heterogeneous, noble metal-contaiing catalyst comprising metals and/or metal oxides.
摘要:
The present invention relates to a process for preparing alkyl methacrylates, especially MMA, and methacrylic acid, based on methacrolein, which has been oxidatively esterified in a second process stage. Methacrolein is obtainable in principle from C 2 and C 4 units. The present process has the advantage that the alkyl methacrylate and methacrylic acid can be obtained in a simple manner, in high yields and high purities, either as a mixture or as isolated product streams. In particular, the process of the invention has the great advantage that especially the ratio of the desired methacrylic acid and alkyl methacrylate, especially MMA, products can be adjusted freely within a wide range and varied by chemical engineering measures and operating parameters.
摘要:
The present invention relates to a process for preparing methyl methacrylate by a direct oxidative esterification of methacrolein with oxygen and methanol, which is conducted in the liquid phase at a pressure of 2 to 100 bar with a gold catalyst. According to the invention, the liquid phase is withdrawn continuously from the reactor and optionally enriched with oxygenous gas, the pH, after the withdrawal, is adjusted to a pH between 5 and 9 by means of addition of a basic solution and this liquid phase is conducted back into the reactor again to an extent of at least 50%.
摘要:
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von Alkylmethacrylaten, insbesondere MMA und von Methacrylsäure auf Basis von Methacrolein, welches in einer zweiten Verfahrensstufe oxidativ verestert wurde. Methacrolein ist dabei grundsätzlich aus C 2 - und C 4 -Bausteinen zugänglich. Das vorliegende Verfahren hat dabei den Vorteil, dass das Alkylmethacrylat und die Methacrylsäure einfach, in hohen Ausbeuten und hohen Reinheiten, wahlweise als Gemisch oder als isolierte Produktströme gewonnen werden können. Dabei weist das erfindungsgemäße Verfahren insbesondere den großen Vorteil auf, dass insbesondere das Verhältnis der gewünschten Produkte Methacrylsäure und Alkylmethacrylat, insbesondere MMA in einem großen Bereich frei eingestellt und durch verfahrenstechnische Maßnahmen und Prozessparameter variiert werden kann.
摘要:
The invention relates to a method for producing methylmethacrylate by direct oxidative esterification of methacrolein and to the production of methacrolein. Said novel method is characterized in that the output and the efficiency of the process, with respect to state of the art, can be significantly increased due to a sequence of different distillation steps.
摘要:
The present invention relates to a process for preparing methyl methacrylate by direct oxidative esterification of methacrolein. Methyl methacrylate is used in large amounts for preparing polymers and copolymers with other polymerizable compounds. In addition, methyl methacrylate is an important constituent for a variety of specialty esters based on methacrylic acid (MAA) which can be prepared by transesterification with the appropriate alcohol. There is consequently a great interest in very simple, economic and environmentally friendly processes for preparing this starting material. In particular the present invention relates to an optimized workup of the reactor discharge of the oxidative esterification of methacrolein by means of which process waste streams can be minimized and process water can be recycled in optimal fashion. The methacrylic acid generated in the process is also optimally recovered and isolated or converted into the commodity alkyl methacrylate. This process moreover has the advantage that fewer demands than described in the prior art are placed on plant apparatus configuration.
摘要:
The present invention relates to a catalytic continuous process for producing methyl methacrylate, said process comprising the step of reacting methacrolein with oxygen and methanol in the presence of a heterogeneous noble-metal-containing catalyst in an oxidative esterification reaction to give methyl methacrylate, characterized in that the stationary concentration of the starting material methacrolein is equal to or less than 12 % by weight based on the total weight of the reaction mixture in the reactor, and the ratio F between the total liquid volume within the reactor expressed in litres divided by the total weight of catalyst in the reactor expressed in kilograms is equal to or less than 4.
摘要:
The invention relates to novel catalysts for oxidative esterification, by means of which, for example, (meth)acrolein can be converted to methyl (meth)acrylate. The catalysts according to the invention are characterised in particular by a high mechanical and chemical stability, even over very long periods of time. This relates in particular to an improvement in the service life, activity and selectivity of the catalyst compared with catalysts from the prior art, which relatively quickly lose activity and/or selectivity in continuous operation, even in media with low water content.