Removal of trace ester compounds from isocyanates
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Dear experts, I have a question: Current isocyanate raw materials contain trace amounts of esters, at levels of several thousand ppm. What methods can be used to remove them, so that their concentration can be reduced to below 10 ppm? For reference, the boiling point of isocyanate at normal pressure is 310 degrees Celsius, while that of esters is 250 degrees Celsius; esters are therefore heat-sensitive substances. I hope experts can suggest the most feasible solutions. Thank you.
There is still too little information to come up with any ideas. Considering only the boiling point, the vacuum level required for vacuum distillation is too high. In other words, it can only be dealt with at the source.
For high-vacuum distillation, whether it’s possible to reach 10 PPm depends on the height of the column used and the requirements regarding yield