Question

In reference to my previous question: Separation of methyl acrylate from ethanol I have successfully get rid of acrid odor by treating ethanol with sodium hydroxide and filtering out the precipitate, but after distillation, there is thinner odor, possible benzene, toluene or similar aromatic hydrocarbon. Also, the remainder after distillation has orange color (before distillation it was pale yellow), which is possibly due to tetracene.

The question is the same, how can I get rid of these aromatics, probably benzene, easy way? Distillation is here not very good method because of similar boiling points (80.1 °C benzene, 78 °C ethanol).

I also do not know how can benzene get into ethanol, maybe it is by-product of previous reaction with sodium hydroxide with something in UV resin?

Answer 1

To remove benzene from ethanol, extractive distillation, adsorption using activated carbon, azeotropic distillation, or pressure swing adsorption can be employed. Contamination or chemical synthesis by-products could explain the presence of benzene in ethanol.

Step-by-step explanation:

To remove aromatic compounds like benzene from ethanol, which can be difficult due to their similar boiling points, one can use several methods. One such method is extractive distillation, where an additional solvent is used that selectively binds to the benzene, changing its volatilities. Another approach is to use adsorption, where materials like activated carbon can selectively remove benzene from the ethanol. Additionally, advanced methods such as azeotropic distillation or pressure swing adsorption can be employed depending on the required purity and quantity.

An unknown introduction of benzene in ethanol could potentially happen through contamination with petroleum products or as an unintentional by-product in chemical synthesis, specifically in reactions involving the breakdown of certain compounds under the presence of UV light or strong bases, such as sodium hydroxide.