Method for preventing undesired polymerisation in a mixture of substances containing ethylenically unsaturated compounds

摘要

A process for preventing undesired polymerization is conducted by maintaining an effective concentration of a stabilizer which comprises N-oxyl radicals in a mixture containing ethylenically unsaturated compounds, wherein(i) an electronic signal which correlates with the concentration of the N-oxyl radicals in the mixture is obtained periodically or continuously,(ii) the electronic signal is compared with a reference value, and(iii) addition of a stabilizer to the mixture is controlled according to the comparison (ii).The signal is preferably obtained by ESR measurement. The process permits efficient use of the stabilizer.