[Guitarmaniac86]

Does anyone have an anhydrous ammonia lecture bottle in the UK that they are willing to lend out for a week or two? I cant seem to get one from BOC, air liquide, or Sigma. I have had a bottle on back order and the delivery date keeps being pushed back.

If anyone has one, we can work out compensation between institutions hopefully...

(I have tried generating it by various methods but to no avail, I cant get it dry enough with CaO for the reaction I want to do).

[phth]

why don't you just make it in situ? Why would anyone online want to send some stranger chemicals?  Red flag.

[Guitarmaniac86]

I have tried generating it in situ*. I cannot get the stuff dry enough. Despite the glassware being oven dried for 24 hours and cooled under a stream of argon. As soon as the dry ice bath is in place and the dry ice condenser is on top of the RBF, water is getting in somewhere and I cant find the leak. It would be easier to have a lecture bottle of ammonia because the attachments mean I have fewer points where a leak can occur.

The lecture bottle of ammonia gas has been on back order for months and the delivery date keeps getting pushed back.

It was a long shot anyway.

*(ammonium sulfate and NaOH pellets heated passed through 50g CaO)
*(Drop sat NaOH into sat ammonia soln pass through 50g CaO)
*(CaO dried in oven 24 hrs after being packed into a glass tube)

[phth]

Why would you put it in an ice bath?  Is it not your fault for not ordering the chemicals you need properly?  Dude you have something that you can distill easily.  Don't use an ice bath when the stuff melts at -77.  distill through wahtever diessicant besides something like CaCl₂.  Seems really simple. My question to you is would sieves selectively absorb moisture form the mixture?

[phth]

If you distilled ammonia after synthesizing it at -50C, would you get water from the mixture?  What is the triple point of water?

[phth]

Ill help you.  1) cool the ammonia solution down to as cold as possible.  Dry ice and acetone/methanol/isopropanol bath: whatever tickles your fancy.  Add water until the temperature is higher than -77 with stirring.  2) distill under vacuum through desiccant onto 3 Å sieves.  4) measure the water content.  5) if unsatisfactory, repeat from step 1. Don't forget to bubble argon through the flask as you cool it or water will get in

[Guitarmaniac86]

Why would you put it in an ice bath?  Is it not your fault for not ordering the chemicals you need properly?  Dude you have something that you can distill easily.  Don't use an ice bath when the stuff melts at -77.  distill through wahtever diessicant besides something like CaCl₂.  Seems really simple. My question to you is would sieves selectively absorb moisture form the mixture?

Its in a dry ice bath not an ice bath. I ordered the chemicals three months before I needed them when at the time, the lead time was only two weeks, but the lead time kept getting pushed back. Now the lead time has been pushed back to the end of April and I ordered the dry ammonia in November.

Ill help you.  1) cool the ammonia solution down to as cold as possible.  Dry ice and acetone/methanol/isopropanol bath: whatever tickles your fancy.  Add water until the temperature is higher than -77 with stirring.  2) distill under vacuum through desiccant onto 3 Å sieves.  4) measure the water content.  5) if unsatisfactory, repeat from step 1. Don't forget to bubble argon through the flask as you cool it or water will get in

I was condensing it directly into the RBF. The ammonia is generated in a separate flask and is connected to an RBF under Ar via the drying tube. I think this is where the problem is. I dry all my glassware in an oven overnight then cool it under vacuum, set it all up and go.

 I will deffo try it your way as it seems a more sensible approach.

[Guitarmaniac86]

Hi phth I just followed your idea and got the royal blue sodium in liquid ammonia colour. Thank you very much for your *delete me*

[BRSM]

I'm glad that worked out for you. I was going to point out that distilling the ammonia from sodium to dry it before doing the Birch is also a good idea. It's also a good way to remove iron impurities from your tank (if you had one) that can really mess up the reduction. I wrote a guide on this a few years back, if it helps: https://chemtips.wordpress.com/2013/03/05/birch_reduction/

I feel your pain with the ammonia---when I ordered it in grad school in the UK it took 6 months to arrive. It was held up for a while because the supplier needed a certain certificate faxed from the university to prove we could order a controlled substance. Unfortunately, it took a number of phone calls and emails to find out that they were waiting on us as they'd never mentioned it.

[Guitarmaniac86]

Thank you for your post BRSM, I have read your post and your article and found it very informative.