摘要:
The invention relates to a process for purifying an ionic liquid, which comprises the steps (a) partial crystallization of the ionic liquid from its melt and (b) separation of the crystals from the residual melt.
摘要:
The present invention relates to a process comprising at least the steps (A) chemical reaction of at least one organic compound in the presence of at least one heterogeneous catalyst in a reaction mixture and (B) removal of the at least one heterogeneous catalyst by means of a magnetic filter, and also the use of a magnetic filter for separating off catalyst particles in a process for the hydrogenation of at least one organic compound.
摘要:
The calculation of the above balance shows that the division of stream (5) into the streams (5a) and (5b) used here leads to the fact that in the neutralization stage no excess sodium formate is produced, so that any ejection can be omitted. Furthermore, the water content of the stream (14) comprising sodium formate recirculated to the first crystallization stage in this case can be set to a very low value.
摘要:
In a process for preparing acrylic acid, an acrylic acid-containing product gas mixture obtained by catalytic gas phase partial oxidation of a C3 precursor of acrylic acid, after direct cooling with a quench liquid, is fractionally condensed in a separating column provided with internals, rising into itself with sidestream takeoff of crude acrylic acid, and the acrylic acid oligomers which form are dissociated and the resulting dissociation gas is subjected to a countercurrent rectification before it is recycled.
摘要翻译:在制备丙烯酸的方法中,通过催化气相部分氧化丙烯酸C 3 N 3前体在用骤冷液体直接冷却后得到的含丙烯酸的产物气体混合物被分级冷凝 在设置有内部件的分离塔中,由于粗丙烯酸的侧流起飞而上升,形成的丙烯酸低聚物被解离,所得的解离气体在再循环之前经受逆流整流。
摘要:
The present invention relates to the use of an optical line detector for regulating the position of the wash front and/or of the build-up front of the crystal bed of a wash column in a melt crystallization process and a corresponding regulation method. The line detector, for example a CCD camera or a linear array of reflection probes, is arranged in such a way that optical properties of the crystal bed can be detected continuously in a region running parallel to the longitudinal axis of the wash column, this region covering the desired setpoint position of the wash front or of the build-up front.
摘要:
A process for the preparation of acrylic acid by: (a) preparation of a gaseous product mixture which essentially has the composition of a reaction mixture of catalytic gas-phase oxidation of C3-alkanes, C3-alkenes, C3-alkanols and/or C3-alkanals and/or intermediates thereof to acrylic acid, which comprises (b) condensation of the gaseous product mixture, (c) crystallization of the acrylic acid from the solution obtained in stage (b), with partial evaporation of the solution under reduced pressure, (d) isolation of the resulting crystals from the mother liquor, (e) recycling of at least a part of the mother liquor from stage (d) to stage (b) and (f) recycling of at least a part of the evaporated solution from stage (c) to stage (b).
摘要:
A process for purifying removal of a chemical target compound from a suspension of crystals thereof in mother liquor in a wash column with forced transport of the crystal bed from the top downward, in which crystals are removed from the lower end of the crystal bed with a rotating removal device and melted, and a portion of the crystal melt is conducted back toward the crystal bed as wash melt, the removal device being secured with a drive shaft conducted into the wash column from the bottom through an inlet having a seal, said drive shaft being driven about its longitudinal axis by a drive unit for rotation and being mounted so as to be rotatable about its longitudinal axis in more than one bearing, such that the mounting in one of the bearings absorbs the downward force acting on the drive shaft, the mounting in two or more bearings absorbs forces acting radially outward from the drive shaft, and the mounting in one bearing is additionally capable of absorbing an upward force acting on the drive shaft.
摘要:
(Meth)acrylic acid is purified by crystallization by a process in which the (meth)acrylic acid is purified by a combination of at least two different dynamic crystallization processes, in particular a suspension crystallization and a layer crystallization.
摘要:
Processes for decreasing fumaric acid deposits in preparing maleic anhydride by heterogeneously catalyzed oxidation of a hydrocarbon with molecular oxygen. Maleic anhydride is absorbed from the crude mixture in an absorbent in an absorption column and desorbed in a desorption column, the entirety or portion of absorbent depleted in maleic anhydride, for controlled precipitation of fumaric acid, being cooled and/or concentrated by evaporating a portion of absorbent such that the difference between the concentration of fumaric acid in the recycle stream at the outlet of the desorption column under existing conditions and the equilibrium concentration of fumaric acid according to the solubility curve after cooling and/or evaporation of a portion of absorbent is ≧250 ppm by weight, and the fumaric acid precipitated as a solid is removed completely or partly from the absorbent recycling system and the fumaric acid-depleted absorbent is recycled completely or partly to the absorption column.
摘要:
A process for removing methacrylic acid from liquid phase P comprising acrylic acid as a main constituent and target product, and methacrylic acid as a secondary component in which the removal is effected by crystallization, the acrylic acid accumulating in the crystals formed and the methacrylic acid in the remaining mother liquor.