Can you help me manufacture sodium ethyl sulfate
ETHYLSULFURIC ACID SODIUM
ETHYLSULFURIC ACID SODIUM
I recommend doing this reaction in bulk. Check out this synthesis for sodium ethyl sulfate :
The temperature control is critical! It must never go above 115 °C otherwise the equilibrium changes and diethyl ether is produced instead of ethyl sulfate.
All reagents must be anhydrous! The presence of water in this reaction reduces the yield. Do not use denaturated ethanol, the denatonium decomposes when heated contaminating the product. If done properly the post-reflux solution should be transparent, possibly with a light yellow tint. If it is yellow or orange you're using impure reagents.
Drying tube on top of the condenser helps to keep out moisture.
Do not evaporate at the final stage! When heated like this the sodium ethyl sulfate breaks down. Only air dry the solution. Using a fan helps to speed things up.
There is a variation of this reaction which uses calcium carbonate before the addition of sodium carbonate. I completely advise against it. It's added to convert the ethyl sulfate into the insoluable calcium ethyl sulfate. Not only is it completely unnecessary but it also adds to the time and workload and contaminates the final product signifficantly. When only sodium carbonate is used the ethyl sulfate is kept in an aqueous solution which you later separate by filtration and dry.
There is also another variation which uses sodium bisulfate instead of sulfuric acid. This does work but the yields are low from my experience. It also contaminates the product which shows in form of milky-like crystals which tend to form on walls of the crystalizing dish.
Requirements
- Ethanol (EtOH / C2H6O / CH3CH2OH, 99%, 180 mL)
- Sulfuric acid (H2SO4 / H2O4S, 95%+, 80 mL)
- Sodium carbonate (Na2CO3 / CNa2O3)
- Water (H2O, 300 mL)
Procedure
To a necked RBF (500 mL) add ethanol and sulfuric acid dropwise 30 min with an addition funnel. Reflux 3 h at 110 °C. Put ice in a beaker (1 L+) and transfer the solution there. Add water (300 mL). Prepare a conc. solution of water and sodium carbonate and slowly pour it into the beaker in portions until pH = neutral. This reation is highly violent! Filter, wash the filter cake with water. Air dry with a fan for ~48 h.Theory
When heated, sulfuric acid protonates the oxygen in ethanol forming an ethyl oxonium ion that parcipitates in a SN2 reaction also known as Fisher esterification. The oxonium releases a small amount of water and the hexacarbon product forming ethyl sulfate, a negligible amount of diethyl ether which boils off and a small amount of carcinogenic diethyl sulfate. The ethyl sulfate is then converted into a sodium salt by the addition of sodium carbonate. The sodium carbonate also neutralizes residual sulfuric acid in an acid-base reaction.. The ice helps to cool things down reducing the violence of the reaction.The temperature control is critical! It must never go above 115 °C otherwise the equilibrium changes and diethyl ether is produced instead of ethyl sulfate.
All reagents must be anhydrous! The presence of water in this reaction reduces the yield. Do not use denaturated ethanol, the denatonium decomposes when heated contaminating the product. If done properly the post-reflux solution should be transparent, possibly with a light yellow tint. If it is yellow or orange you're using impure reagents.
Drying tube on top of the condenser helps to keep out moisture.
Do not evaporate at the final stage! When heated like this the sodium ethyl sulfate breaks down. Only air dry the solution. Using a fan helps to speed things up.
There is a variation of this reaction which uses calcium carbonate before the addition of sodium carbonate. I completely advise against it. It's added to convert the ethyl sulfate into the insoluable calcium ethyl sulfate. Not only is it completely unnecessary but it also adds to the time and workload and contaminates the final product signifficantly. When only sodium carbonate is used the ethyl sulfate is kept in an aqueous solution which you later separate by filtration and dry.
There is also another variation which uses sodium bisulfate instead of sulfuric acid. This does work but the yields are low from my experience. It also contaminates the product which shows in form of milky-like crystals which tend to form on walls of the crystalizing dish.
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synthesis failed, was it because I poured the sulfuric acid too fast?
- By Felix34-73
synthesis failed, was it because I poured the sulfuric acid too fast?
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How do you know that the synthesis has failed? Did you try to crystalize the product?
Your temperature readings are good but it should be noted that they depend on what the quality of your reagents. On the photos you provided I note the orange color which is likely caused by the decomposition of the denatonium in the EtOH or the formation of diethylether. If you've used EtOH (Anhydrous, 99%+) and this occurs try 105 °C or 100 °C. I should also point out that this does not mean the synthesis has failed just that a few contaminants formed. You should attempt to crystalize. A real issue would be if the mixture turned red which hints the formation of diethyl sulfate. To simply check for byproducts, smell the mixture (not for long, not particurarly pleasant) . If you smell diethylether or if you observe bubbles floating on top of the liquid during the synthesis that means you're making diethylether instead.
With clearly failed attempts I've also seen carbon precipitating out which then has to be filtered (personally I wouldn't use the product afterwards anyways in this case). Considering none is visible in your case I'd try to crystalize the product. I think you have not failed. Is there a problem with the crystallization? You haven't given much info in regards to what leads you to believe the synthesis has failed. If there is more information elaborate on the issue. If you're worried about the contaminants which cause the color change they can be removed using activated carbon.
As for my advice on the addition rate of the acid if you don't exceed 70 °C you should be fine. The goal is to not achieve boiling. From my experience adding over 30 min is fine. If you worry about too fast of an addition and have no addition/dripping funnel you can add the H2SO4 whilst submerging the flask in an ice bath to play it safe. Then attach the flask to the refluxing setup. I've done this in the past when no funnel was available and checked temp. to be >70 °C.
Here a few follow-up questions to help me diagnose issues :
Your temperature readings are good but it should be noted that they depend on what the quality of your reagents. On the photos you provided I note the orange color which is likely caused by the decomposition of the denatonium in the EtOH or the formation of diethylether. If you've used EtOH (Anhydrous, 99%+) and this occurs try 105 °C or 100 °C. I should also point out that this does not mean the synthesis has failed just that a few contaminants formed. You should attempt to crystalize. A real issue would be if the mixture turned red which hints the formation of diethyl sulfate. To simply check for byproducts, smell the mixture (not for long, not particurarly pleasant) . If you smell diethylether or if you observe bubbles floating on top of the liquid during the synthesis that means you're making diethylether instead.
With clearly failed attempts I've also seen carbon precipitating out which then has to be filtered (personally I wouldn't use the product afterwards anyways in this case). Considering none is visible in your case I'd try to crystalize the product. I think you have not failed. Is there a problem with the crystallization? You haven't given much info in regards to what leads you to believe the synthesis has failed. If there is more information elaborate on the issue. If you're worried about the contaminants which cause the color change they can be removed using activated carbon.
As for my advice on the addition rate of the acid if you don't exceed 70 °C you should be fine. The goal is to not achieve boiling. From my experience adding over 30 min is fine. If you worry about too fast of an addition and have no addition/dripping funnel you can add the H2SO4 whilst submerging the flask in an ice bath to play it safe. Then attach the flask to the refluxing setup. I've done this in the past when no funnel was available and checked temp. to be >70 °C.
Here a few follow-up questions to help me diagnose issues :
- Have you tried to finish the synthesis and crystalize the final product?
- Are all your reagents anhydrous (I know I keep saying this but this synthesis showed to be particurarly sensitive to H2O, I've used 95% H2SO4 with success for this no need to go over that which is very costly)
- Is your EtOH denaturated?
- What concentration of H2SO4 are you using?
- Was the reflux calm? (There should be no smoke visible in the condenser)
- What ratio of acid to alcohol did you use?
- By Felix34-73
1) I didn't try to crystallize, I made it pH neutral, but I thought it was not the product and threw everything away.
2) all my reagents are anhydrous
3) ethanol was not denatured
4) when I drop sulfuric acid into ethanol
5) my degree is broken, it was a little difficult to control the degree, I will order a new degree
6) 96%
2) all my reagents are anhydrous
3) ethanol was not denatured
4) when I drop sulfuric acid into ethanol
5) my degree is broken, it was a little difficult to control the degree, I will order a new degree
6) 96%
Cool. Unfortunate you threw it away but I get it. From what you say it seems you're good in terms of quality control. Color change to yellow/gold is ok, orange is still fine. You never want red. I wish you good luck with the synthesis in the next run.
- By Felix34-73
Also, my other electronic thermometer, which I will make with a new glass thermometer, is broken.
As I said in my post you neutralize the solution and air dry. Once the solvent has evaporated solid crystals will fall out. Use a crystalizing dish with a fan. Do not apply heat the product is highly prone to thermal decomposition.
- By Felix34-73
Ethanol is broken, I think I will do it with new ethanol, this time I will use 98% sulfuric acid
This looks good. I got about the same result possibly with a lighter tint of yellow but yours is probably the same and it's just the contrast of the video.
- By Felix34-73
The ethanol I used was really watery so pH neutralization was very difficult and my 2 synths were garbage I'm so depressed 
- By Felix34-73
I use this, but this is ethanol fireplace fuel and it's very watery, I think this ethanol doesn't neutralize the pH, what do you think about it?