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help with non polar extraction...

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Coitus:
I have also noticed better yields with gassing. It's probably due to my always going overboard on adding the acid when titrating.

You don't have to worry about ph when gassing, which makes it quicker and easier in my book. No boiling off H20 or evaping!!

ChemNewbie:
And if everything went perfectly, there's no reason yields shoud be any less for the titrators. But, there are a lot more opportunities for little mistakes here and there with titration. There are several more steps involved, with chances to lose just a tiny bit of product with each one. I think Geez once referred to this as "Mechanical losses". (ie more liquids being transferred to more pieces of labware = more residuals left behind that may contain product).  But I will say that pH is still important in gassing to a degree, because Swic has definately managed to over gas a batch here and there, and caused himself more work during the cleanup process than should be neccessary.

SHORTY:
Im not sure what extra steps would be taken but i just add a little dh2o after washing the np, then add my hcl shake, check ph, shake, check ph, shake, check ph and drain into visionware pan.  I sometimes get the ph after the second shake and have managed to hit it on the first try a couple times.  But it usually takes three.  Anyways, when i gas i add a drying agent to the np after washing, a small amount of yeild may be lost in the drying agent.  By this time i have went from the sep to another vessel with drying agent then filter into yet another vessel and then gas.  So actually i do more transferring when gassing than i do when titrating.  Which is probably why i prefer titrating.  I hate washing glassware.

geezmeister:
If you live in a humid climate, there will be times that titration will serve you better than gassing. Under very humid conditions, gassing can become difficult to do successfully. There is no real reason for the yields to be different except for lab technique and those "mechanical losses" to the sides of the glassware, filters, etc.

I know of lot of folks who gas and filter through coffee filters. This is a poor way to do it. Get some filter paper. You can wash a large amount of meth out of those coffee filters, which are absorbent filters. You can rinse most of it out, but it will be mixed with paper fiber and the oils, waxes, and trash the filter catches. You can titrate and never use a filter at all. Pan the acetone wash to a corner, then out of the pan, and let it all air dry.
No losses to filters. No paper filters in the trash. Less expense, evidence, loss.

Jacked told us that a long time ago. As ususal, he was completely correct.

SHORTY:
Your are 100% right geez!  I live in a tropical climate, which is of course always very humid.  On top ot that i have no A/C in my lab.  I never use filters for meth, i just decant the acetone wash into a empty acetone bottle and cap it then into the freezer for a rainy day.  In the past, when i did use the gassing method, i would add dh20 to the np after gassing and seperate the dh20 and evap.  I then realized that i was wasting time and effort trying to gas and just started titrating.  It was a bit frustrating in the beginning trying to test the ph and shit but after doing it for a while its quite simple.

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