Author Topic: Idea for sep. of NMP/GBL  (Read 1065 times)

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M3Psych

  • Guest
Idea for sep. of NMP/GBL
« on: September 21, 2004, 06:36:00 PM »
First off, forgive me if this has been covered or makes no sense... I have not found anything relating to this method here or anywhere else, yes I UdTFSE...

I've read that NMP is very resistant to hydrolysis when pH is 2 - 10 (and < 2 or > 10 depending on pH+temp). So I've come up with an ideas of how to more easily liberate GBL from an NMP/GBL (+Bitrex) mixture...

NMP is stable in pH 2-10 (

http://www.ispcorp.com/products/industrial/content/products/mpyrol.html

), how about steam distallation to sep the NMP/GBL from the Bitrex. Followed by Chromic's NaHCO3 method of basic hydrolysis to open the lactone ring of GBL but not NMP. I'm assuming that NMP is more resistant to this weak basic hydrolysis than GBL because the 3 N bonds in NMP are stronger than the 2 O bonds in GBL. Am I right? At what pH/temperature does GBL succumb to NaHCO3 hydrolysis? I've read the pH of NaHCO3 is 7.9-8.4 at 15C. Does this increase with temperature? Does it ever pass pH 9-10?

If everything is good so far, the GHB synthed from this hydrolysis could then be separated from the NMP by the addition of water followed by steam distillation, with the NMP coming over as distillate (and discarded). Would it still be necessary to wash the NMP/GHB to remove any traces of NMP?

If this works it would skip the step of esterification of GHB to GBL and save 1 or 2 distillations. Right? The only problem would be quantitizing the GHB.

M3Psych

  • Guest
No takers? Come on people, GBL+NMP mixtures...
« Reply #1 on: September 22, 2004, 05:00:00 PM »
No takers? Come on people, GBL+NMP mixtures can bee found in abundance... if this method is workable then it would be nice to know.

The big question is: Does NaHCO3 catalyzed hydrolysis of NMP occur under the same conditions as NaHCO3 catalyzed hydrolysis of GBL?

Surely someone must have some sort of idea...

Nicodem

  • Guest
The big question is: Does NaHCO3 catalyzed...
« Reply #2 on: September 22, 2004, 07:58:00 PM »
The big question is: Does NaHCO3 catalyzed hydrolysis of NMP occur under the same conditions as NaHCO3 catalyzed hydrolysis of GBL?

No.

No takers? Come on people, GBL+NMP mixtures can bee found in abundance...

Not in my neighborhood.


M3Psych

  • Guest
Re: The big question is: Does NaHCO3 catalyzed
« Reply #3 on: September 23, 2004, 05:09:00 PM »

The big question is: Does NaHCO3 catalyzed hydrolysis of NMP occur under the same conditions as NaHCO3 catalyzed hydrolysis of GBL?

No.




I guess I'll have to write and direct a play about this techinique then.


Not in my neighborhood.




Perhaps not in your neighborhood, but if you live in the United States there are at least 2 major chain hardware stores I can name which either sell or will order for you a particular brand or brands of products containing NMP/GBL.

If not, I can think of at least 2 industrial/commercial  chemical manufacturers which offer NMP/GBL based cleaning solvents (think taggers).


M3Psych

  • Guest
Improved technique for sep. of NMP/GBL?
« Reply #4 on: September 23, 2004, 07:29:00 PM »
Ok, well here's the technique which will be used by the main characters in my play, "Bees, Buzzing, and the letter G" (working title). Comments and suggestions would be very much appreciated.

Ingredient               Quantity          Purpose
GBL               70%            Solvent
   NMP               20%            Solvent
   Orange Scent            Unknown         Scent
Denatonium Benzoate (Bitrex)     Unkown         Ingestion Deterrant


Step 1:

Removal of denatonium benzoate (Bitrex)
Steam distillation of 100mL GBL/NMP + 100mL dH2O mixture will effective separate GBL/NMP from Bitrex. GBL, NMP and “orange scent” will steam distill. Collect 170mL of distillate (~29% GBL=[50mL, 56g GBL] ~18% NMP=[30mL])

Step 2:
   Removal of “orange scent” from distillate
      “Orange scent” is immiscible in H2O and can be drawn off with pipet

Step 3:
   Preparation of NaGHB using NaHCO3 (Chromic’s Method)
57.1g of NaHCO3 are added to 235mL of dH2O in a glass container. Slowly heat the solution to boiling with gentle stirring. Reduce heat to light boil and slowly add the 170mL of the distilled GBL/NMP solution. Set up to boil under reflux (NMP vapor may be toxic). Maintain light boiling reflux for 30 minutes. Check pH with universal paper. pH should be 6-8. If pH goes too high (> 9-10), hydrolysis of NMP -> 4-(methylamino)-butyric acid will occur. ~91.84g of GHB would be made during this synthesis assuming a 100% successful distillation. 68.88g would be made assuming a 75% successful distillation. 49.27g of GHB would be made assuming a 50% successful distillation.

Step 4:
   Separation of NaGHB from NMP by distillation
The ~405mL solution of GHB/NMP is distilled down to 200mL and the distillate is discarded.10g of activated charcoal is added to the reaming ~205mL of solution and boiled gently for 10 minutes.

Step 5:
   Removal of charcoal, final boil and quantitative analysis
The 205mL of GHB/charcoal solution is gravity filtered as many times as it takes for the solution to be without visible trace of charcoal. Solution is then gently boiled  until ~150C is reached and/or bubbling stops to remove any remaining NMP and to drive off H2O. This solution is then poured into a Pyrex baking dish, covered with plastic wrap and allowed to cool. After cooling, the GHB will have (hopefully) hardened. A suitable container is placed on the scale and weighed. The NaGHB is then placed into this container and the weight of the container is subtraced from the total weight. The amount should be weighed to the nearest 0.1g. A scale which is not capable of this should not be used.