Ethanolamines, being the major chemicals in the detergent and gas scrubbing fields, are made by reacting ethylene oxide and excess ammonia. Ethylene oxide is fed, together with aqueous ammonia solution and recycle amines to a reactor where mono-, di-, and triethanolamines are formed. The reaction sequence is;
Ammonia + Ethylene oxide $\underrightarrow k_1$ Monoethanolamine
Monoethanolamine + Ethylene oxide $\underrightarrow k_2$ Diethanolamine
Diethanolamine + Ethylene oxide $\underrightarrow k_3$ Triethanolamine
The distribution of amines in the product depends on the ratio of ammonia vs. ethylene oxide, the quantity of recycle amines and the reaction conditions.
The effects of temperature, feed ratio (Ammonia/Ethylene oxide), recycle amines, and the concentration of water were studied in a batch reactor and on a continuous tubular reactor system.
It was confirmed that temperature has negligible effect on the distribution of products in the temperature range of 50 ℃ to 90 ℃.
As the ammonia vs. ethylene oxide ratio decreases the fraction of triethanolamine in the product increases.
The ratios of the rate constant $K_2(k_2/k_1)$ and $K_3(k_3/k_1)$ were found as follows;
$K_2$=21.1 - 0.42($H_2O$)
$K_3$=16.4-0.25($H_2O$)
where ($H_2O$) in moles/liter.
Recycle of monoethanolamine and diethanolamine has such an effect that it may be applied to fit the demand requirements of each amines.
With a production capacity of 5,000 tons/year, the total investment is 1,176 million wons with the rate of return on investment of 15.6% and the payout time is 3.1 years.
