A kind of method for separating and recovering acrolein from the hydration product of 3-hydroxypropionaldehyde prepared by hydration of acrolein

Abstract

The invention relates to the field of chemical industry, and discloses a method for separating and recovering acrolein from a hydration product of 3-hydroxypropionaldehyde prepared by hydration of acrolein. The obtained 3-hydroxypropionaldehyde solution is discharged from the bottom of the acrolein rectification tower, a part is returned to the acrolein rectification tower through the falling film evaporator, and a part is collected for subsequent reactions; Pass into the bottom of the acrolein spray tower, pass into the chilled water and the polymerization inhibitor solution, the formed condensate is discharged from the bottom of the acrolein spray tower, part of it is refluxed to the top of the acrolein rectification tower, and part of it is recovered as hydration raw materials. Use; the formed non-condensable gas is discharged from the top of the acrolein spray tower as waste gas treatment. The method of the invention has low acrolein content and low energy consumption after dealdehyde removal, the spray condensate can be directly used in the ingredients of subsequent reactions, the acrolein recovery rate is high, and the non-condensable waste gas generated in the recovery process is small.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for separating and recovering acrolein from a hydration product of 3-hydroxypropionaldehyde prepared by hydration of acrolein. Background technique [0002] The hydration of acrolein to 3-hydroxypropionaldehyde is the first step in the synthesis of 1,3-propanediol. In order to improve the selectivity of 3-hydroxypropanal, the conversion rate of acrolein is low, and the content of unreacted acrolein in the hydration product is high. Due to the active chemical properties of acrolein and its low solubility in water, the 3-hydroxypropanal produced by the hydration reaction is prone to side reactions with acrolein. Therefore, it is necessary to separate out acrolein in time. [0003] The traditional process generally adopts vacuum distillation to recover acrolein. The cooling medium requires low temperature, large dosage, and low heat exchange efficiency of the tower top co...

AI Technical Summary

Problems solved by technology

The domestic patent CN1398843A proposes to introduce inert gas from the bottom of the rectification tower to reduce the temperature of the rectification tower, but the addition of inert gas reduces the condensation efficiency at the top of the tower, and the tail gas has a high acrolein content, which makes it difficult to treat the waste gas containing acrolein; the patent CN1803750A proposes to adopt the inert gas stripping-absorption mode, which cancels the reboiler heating and avoids the side reaction of the tower kettle material, but the use amount of the inert gas is large, and the concentration of acrolein in the gas phase at the top of the stripping tower is low, which makes the absorption The efficiency of the tower is low, the amount of absorbent required is large, and the generated inert gas containing acrolein is difficult to reuse, and the waste gas treatment load is large

Images