Monoethanolamine, diethanolamine, triethanolamine – how to identify them
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In reality, compared to diethanolamine and triethanolamine, monoethanolamine is easier to identify. However, once diethanolamine and triethanolamine crystallize, it becomes difficult to tell them apart. What are some good methods for identification? Also, when comparing marlene with monoethanolamine, both have a certain ammonia smell; but how can they be distinguished from each other? Do all of these substances crystallize when temperatures drop in winter?
Ethanolamine: NH2CH2CH2OH; Diethanolamine: NH(CH2CH2OH)2; Triethanolamine: N(CH2CH2OH)3. For specific differences, refer to Baidu Baike – differences in melting point, molecular weight, etc. The production process involves reacting ammonia with ethylene oxide; the addition of two molecules of ethylene oxide, three molecules of ethylene oxide, respectively, yields three types of ethanolamine. These products are then separated through distillation
Prepare a 1% solution and measure the pH value; the pH values of the three are quite different.
Without conducting chemical analysis, it is possible to make distinctions based on factors such as odor, freezing temperature, and color: Odor: Monoethyl has a strong ammonia smell; diethyl has a less intense smell; triethyl essentially has no smell. Freezing temperature: As the temperature drops, diethyl freezes first, followed by triethyl; monoethyl requires a temperature below 0 degrees Celsius to freeze. Color: Monoethyl is almost colorless and transparent; diethyl is slightly colored; triethyl has the darkest color among them
Under the same circumstances and conditions, color and odor are generally what matter!