an improved process of methylene bis (dibutyl dithiocarbamate) astm colour for the production of less than 2

摘要

The subject-matter of the invention is a process for manufacturing 4,4'-methylene-bis-(dibutyl-dithiocarbamate) with ASTM colour less than 2, by reacting aqueous solutions of dibutyl amine and sodium hydroxide with carbon disulfide at a temperature below 42 DEG C, treating the obtained reaction product with methylene dichloride followed by vacuum stripping at a temperature below 122 DEG C and a pressure above 5 kPa, phase separation and filtration of the precipitated sodium chloride, characterized by keeping the temperature of the mixture during the reaction with carbon disulfide at or below 15 DEG C and performing the vacuum stripping in 2 steps, first at a temperature of from 45 DEG C to 100 DEG C and at a pressure of from 5 to 50 kPa, then carrying out the phase separation at 35 DEG C to 50 DEG C, and thereafter performing the second vacuum stripping of the separated organic phase also at a temperature of from 45 DEG C to 100 DEG C and at a pressure of from 5 to 50 kPa.