Methods for separating methanol and toluene
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During the production of a certain product, toluene is mixed into methanol, with about 15% toluene and 85% methanol; the monthly production volume is around 15–20 tons. Are there any other methods aside from adding water for separation followed by distillation?
This post was last edited by zdl1966 on 2018-5-13 20:43. Can distillation be used directly taking advantage of the different boiling points—[toluene 110.6, methanol 64.7]? Will an azeotrope form?
Methanol and toluene do not have an azeotrope, so ordinary distillation can be used directly
This post was last edited by *amingteda on 2018-5-18 21:53. There seems to be no azeotrope; you can check the manual. By referring to the \"Solvent Handbook\" by Cheng Nenglin, it is found that methanol and toluene have an azeotrope, making separation difficult using conventional distillation methods. Separation can be attempted using methods such as pressure swing distillation and extractive distillation; the key factor is the separation cost.
There is no comparative experience from practice. It seems that water-based extraction is a promising method; firstly, the extraction step is more energy-efficient than distillation. As for the energy consumption associated with separating methanol from water, it’s not clear compared to that of traditional distillation. Additionally, it remains to be determined whether membrane separation is feasible
Methanol and toluene are azeotropic, and they cannot be separated by distillation. The common approach nowadays is to first separate methanol and toluene using water, and then distill the methanol-water solution; I wonder if there are any better methods.
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Are you kidding me... It’s better to check the literature first
Extraction distillation is generally used; for example, xylene is added at a solvent ratio of 1:1 to facilitate separation, in order to avoid the introduction of water. Otherwise, after washing, trace amounts of toluene remain in the methanol and need to be separated again.