Patent TW-202231329-A (TW)
Title: Compound purification method capable of obtaining compound with high purity at high yield and low cost
Inventor: ARAI SHOGO
IPC: C07C57/07
Filed: 2021-11-19
Abstract: The present invention provides a compound purification method for obtaining the compound with high purity at high yield and low cost. The present invention relates to a compound purification method which utilizes a purification device comprising having a crystallization device having a crystal formation portion and a cleaning column having a mechanism for compulsorily conveying crystals, and is characterized in that: the crystallization device has N tanks (N≥2), in which the first tank serves as the downstream and the Nth tank serves as the upstream being connected in series; at least the first tank is provided with a crystallization tank having a cooling mechanism, and the second and subsequent tanks are crystallization tanks or curing tank. The purification device is provided with a pipeline for supplying purified solution containing the compound to at least one tank. The cleaning column is provided with a pipeline for moving out the product, a pipeline for sending the mother solution back to the crystallization device, wherein the pipeline sending back to the crystallization device is at least connected to the Nth tank. The crystallization device is provided with a pipeline for supplying slurry from the Nth tank to the cleaning column, a pipeline for supplying slurry from the downstream tank to the upstream one tank, a pipeline for supplying mother solution from the upstream tank to each of the first to (N-1)th tanks. At least one of the (N-1)th pipeline for supplying slurry from the downstream tank to the upstream one tank is the pipeline for supplying slurry to the upstream one tank through the solid/liquid separation device and is provided with a pipeline for sending mother solution having crystals removed by the solid/liquid separation device back to the original tank. The pipeline for supplying mother solution from the upstream tank to each of the first to (N-1)th tanks includes a pipeline for directly supplying mother solution from the upstream one tank and at least any one of the pipelines for supplying mother solution from the upstream one tank through the solid/liquid separation device. The purification method includes the following steps: a step for generating crystals of the compound in the crystallization device; a step for discharging at least a portion of mother solution out of the purification device; a step for separating the slurry containing the generated crystals into the mother solution and a slurry having increased crystal concentration; a step for returning at least a portion of the separated mother solution to the original tank; a step for supplying the purified liquid containing the compound to the crystallization device to be mixed with the slurry in the crystallization device; a step for sequentially supplying the slurry from the downstream tank to the upstream one tank among the plurality of tanks included in the crystallization device; and, a step for supplying at least a portion of the slurry from the crystallization device to the cleaning column; wherein the purified liquid containing the compound has a purity higher than the mother solution discharged out of the purification device; the purity A1 of the mother solution in the slurry supplied to the cleaning column is above 80 mol%; and, the difference (A1-A2) between A1 and the purity A2 of the discharged mother solution is above 5 mol%.