Severe GHB upscalling problem! Yellow GHB.

[diyguy]

Hello comrads,

I need your help

At the moment i am dealing with a severe Sodium Gamma-Hydroxy Butyrate (Na-GHB) upscalling problem.

I thought i was a real chef, but now i'm hit with the fact that i don't know shit.

I have a methode that works really well in smaller batches. But now I use a higher volume ALL my ghb turns yellow or even dark Yellow or even orange.

When i make 20L in 1 batch all goes well. But when I go up to 50L or 70L things start taking a turn for the worst.

Materials used
Stainless steel boilingpan 100L
Stainless steel serving spoon
30L Distilled water
13,50kg Sodium hydroxide
30L GBL (Gamma-butyrolactone)


My process

I put 25L distilled water in the pan.
I add 11,25 kg of sodium hydroxide.

I stirr with the spoon let the reaction take place and i put the lid on the pan.

Then the next day i come back. I check the temperature, its cold. so i prepare in a separate pan:
5L distilled water
2250grams of sodium hydroxide
Let the reaction take place. But now i dont let it cool down (to much). Now i start adding GBL (Gamma-butyrolactone). I do this until It warms up to above 80 degrees celcius. Then i add this pan to the big pan (to get some heat going). The pan is now 50degrees celcius. Now i keep adding all the GBL in portions and Occasionally stirring with the spoon. This whille keeping the temperature under 100 degrees celcius. When it gets to hot, i wait a while and then when the temperature is 60 or 70degrees celcius i add more. But when i am at 70-80% of the GBL addition the batch turns slightly yellow. This precipitates. When l am done the pan seems dark Yellow almost orange even.

The questions i have
What is happening?
How can i prevent this from happening?
Can i fix these broken batches?

Thanks for reading, looking forward to your insights.

 

[G.Patton]

Hello. First of all, you take not enough NaOH. You have to take 15945g for 30L of GBL in accordance with reaction equation. Really good chef has to know about basics =)

Secondly, I have assumption, that you just overheat reaction solution. Do it slowly to avoid such height temperatures.
Read more in this patent A novel process for the preparation of sodium gamma-hydroxybutyrate https://patentimages.storage.googleapis.com/e0/e5/66/d5ef4bdf396bf6/WO2009129350A2.pdf

Do you make sodium oxybate in crystalline form? A little yellowish color is okay for this substance.

 

[diyguy]

@G.Patton
I have read it thorough and I love it, thanks. Very interesting. For scalling up this paper has given me an interesting insight on how to approach that.

But Im still not sure what is happening.
Because it doesnt seem to me that it happens at a certain temperature. Maybe thats its like burning a cake... only previous experiences of my own kinda contradict that. Its still a mystery to me.

The goal is to make a aqueous solution of NaGHB. Not solid form.

 

[diyguy]

I run a few tests and I found that in bigger batches the stirring is very important.

I would recommend to add Caustic soda (40degrees celcius) in small portions to the GBL (40 degrees celcius).

With every addition of the caustic soda its important to stir until there is no temperature rise anymore. Keep the temp between 40 en 60 degrees. So add the causticsoda until it rises to 60 degrees celcius, then let it cool to 40 degrees celcius and then add again. The stirring is most important during the addition of causticsoda. When there is no more temperature rise and it even starts to drop its les important, so if you are stirring manualy this is the moment you can walk away and do some other stuf until the temp has dropped. Well keep this going until there is no more caustic soda and you are done.

Have a great one

And thanks @G.Patton for the contribution of knowledge.

 

[G.Patton]

It's good. It's known that all chemical reaction (except for boiling ones) have to be stirred well. You're welcome.