Liquid withdrawing tray for purification column, purification column, and method for purification

Abstract

In the purification of an easily polymerizable compound such as (meth)acrylic acid by the use of a purification column adapted to withdraw a liquid from the middle portion of the column, a novel liquid withdrawing tray adapted to prevent the compound from polymerization effectively and permit the purification to be stably performed for a long time, a purification column using this tray, and a method for purifications using this purification column are provided. The liquid withdrawing tray for the purification column is composed of a liquid receiving plate and a liquid withdrawing tube for withdrawing the liquid from the liquid receiving plate.

What is claimed is:  
     
         1 . A liquid withdrawing tray for a purification column, comprising a liquid receiving plate and a liquid withdrawing tube communicating with said liquid receiving plate and serving the purpose of withdrawing the liquid.  
     
     
         2 . A tray according to  claim 1 , wherein said receiving plate has the shape of a funnel.  
     
     
         3 . A tray according to  claim 1 , wherein said liquid receiving plate is provided in the upper outer periphery thereof with notches.  
     
     
         4 . A tray according to  claim 1 , wherein the angle of the downward slope of said liquid withdrawing tube from the horizontal direction is in the range of 0.5-80°.  
     
     
         5 . A purification column provided in the column interior thereof with a liquid withdrawing tray according to any one of claims  1 - 4 .  
     
     
         6 . A purification column according to  claim 5 , wherein the largest cross sectional area, S 1 , of said liquid withdrawing tray is in the range of 10-90% of the cross sectional area, S 2 , of said purification column.  
     
     
         7 . A purification column according to  claim 5 , wherein said liquid receiving plate is provided thereunder with at least one spray nozzle for spraying the lower side of said liquid receiving plate with a liquid.  
     
     
         8 . A purification column according to  claim 5 , wherein said liquid receiving plate is provided thereover with at least one liquid injecting nozzle for injecting a liquid into the liquid surface in said liquid receiving plate.  
     
     
         9 . A method for purifying an easily polymerizable compound, which comprises effecting the purification by the use of a purification column set forth in  claim 5 .  
     
     
         10 . A method according to  claim 9 , wherein said easily polymerizable compound is at least one member selected from the group consisting of (meth)acrylic acid and esters thereof.