Stacking Columns for Ethanol Fractionation - Snyder vs Vigreux

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In summary: Vigreux column in place of a Snyder column in order to improve ethanol distillation efficiency. He says that doing so would require insulating the column to prevent flooding, as well as tempering the ethanol distillation process to avoid temperature fluctuations. Additionally, he warns against distilling too quickly or overfilling the pot, as these actions could lead to column flooding.
  • #1
MoleMan
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I am fractionally distilling ethanol out of solution.
I have done this with a Snyder column (3-ball)and most of my fraction came over between 79°+ and 83°.
I am wanting to improve upon this and am thinking about stacking a Vigreux in there.

Should the assembly have the Snyder on the top or the bottom?
 
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  • #2
Were all three balls chattering throughout the distillation? If not you might have had a column that was flooding. If they were, it probably doesn't matter how you place the vigreux column but I would place it on top of the snyder and be careful of flooding. The longer the column, the more likely you will need to insulate it to be able to maintain a distillation.
 
  • #3
Thanks for the reply.

To answer your question. Yes the Snyder was insulated with the ol paper towel/Al foil-sandwich wrap. It chattered away for hours.

I am now running the Vigreux column separately to see what temp the ethanol comes over at. I expect it to be slightly higher as I have read that a Snyder is more efficient than a Vigreux.

If I could stack columns instead of multiple passes it would be nice.

What are your thoughts on efficiency, 200mm Vigreux vs. 3-ball Snyder.
 
  • #4
I think the Vigreux would have more theoretical plates but technique will determine the actual efficiency. Don't distill too fast. Temperatures can fluctuate if the pot is overfull, there is bumping and if the pressure in the lab changes. Opening the lab door or sliding up the hood's screen can have some big effects on atmospheric pressure in the lab and the hood.
 
  • #5
I use a 3-stage Snyder column regularly, and the time it takes to the separation is literally half that required for a Vigreaux colummn of twice the length...and, the Snyder column does a far better job of separation! It would seem that a 3-stage Snyder beats a two-foot Viugreaux.

DrB
 

1. What is stacking columns for ethanol fractionation?

Stacking columns for ethanol fractionation is a technique used to separate different components of a mixture based on their boiling points. This technique involves using two columns, one on top of the other, to increase the separation efficiency and achieve a higher purity of the desired component, in this case, ethanol.

2. What is the difference between Snyder and Vigreux columns?

Snyder and Vigreux columns are two types of columns used in ethanol fractionation. The main difference between them is their internal structure. Snyder columns have a larger surface area and longer path length, allowing for a higher separation efficiency. Vigreux columns, on the other hand, have a more complex internal structure with multiple indentations, which increases the number of theoretical plates and improves separation.

3. Which column should I use for ethanol fractionation?

The choice between Snyder and Vigreux columns depends on the specific requirements of your experiment. If you need a high purity of ethanol, a Snyder column would be more suitable. However, if you need a higher separation efficiency, a Vigreux column would be a better option. It is important to consider the desired outcome and the properties of the mixture before choosing a column.

4. How do I set up a stacking column for ethanol fractionation?

To set up a stacking column for ethanol fractionation, you will need two columns, one on top of the other, with a distillation head connecting them. The bottom column should contain the mixture of components, and the top column should contain a packing material, such as glass beads or steel wool. The mixture is heated, and the vapors rise through the top column, where the separation occurs. The desired component is then collected at the top of the top column.

5. What are the advantages of using stacking columns for ethanol fractionation?

There are several advantages of using stacking columns for ethanol fractionation. These include higher separation efficiency, improved purity of the desired component, and the ability to handle a larger volume of the mixture. Stacking columns also allow for more precise control over the separation process, making it a preferred technique for scientists working with complex mixtures.

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