in situ HBr in acetic acid

[lugh]

Post 205087 (missing)

(lugh: "Re: CH2Cl2 to CH2I2", Chemistry Discourse)

[Rhodium]

And an improved method from JCS can be found at

https://www.thevespiary.org/rhodium/Rhodium/chemistry/ch2i2.html

[hsark]

I thank you for the info on the finkelstien and delpine. But i have carried out these reactions and failed with the delpine. Im going to try them again soon though. my question though was about a post that Ritter mentioned.""Improved Method for the Synthesis of Alkyl Azides" P.238 Vol 22, 1957.  Look in all the major old journals (JACS,JCS,JOC) and you'll surely find it in no time."I was hoping someone could point me in the right direction. Its not the bromosafrole thats a problem. Its getting it to mda with respectable yields. The bromo/azide/mda reactions with alaquat 336 without distilling the azide and then SnCl reduction  yielded a 40.96%. Im going to distillthe azide next time.

It sure would be great to see the write up you mentioned herr Ritter.   
Someone once told me if you dont like it move.So i did.

[endo1]

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J/J the proportions were 1L 33% HBr in acetic acid to 450ml safrole.
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SW uses less HBr (500ml to 300ml sas) but stirring is necessary. HBr  in GAA chilled down in freezer over night and sas cooled as much as possible without freezing before adding both to a gem jar with concave bottom sealed tightly(SW had problems with flat bottom flasks due to friction of the stir bar). Place jar on magnetic stirrer and place whole thing in deep freeze for 48 hours! Quenched on ice and washed as usuall. SW gets 90%+ yields. SW thinks that 24 hours is probably sufficient but he leaves it for 48 because of his schedule.

SW finds that occasionally the "black tar" near the end of the still during purification erupts in to the ash volcano mentioned earlier in the thread. The more "black tar" or "darkness" the more likely the eruption. Sometimes its much more like an explosion than a volcano. SW uses good asperator with high water pressure and cold mountain water. He starts collecting his bromo at about 145 and collects till about 162 (where the flask is almost empty and distilate begins to darken a tad). Some things SW thinks might minimize the "black tar" are:
-wash it while its still cold and wash it well
-keep it in the freezer untill ready to distill it (and after too)
-use vacuum for entire distillation including solvent stripping. and use best vacuum possible for collecting bromosafrole as the distillate. (check for leaks etc.)
-dont run the water anywhere else in the building! this can change the water pressure which may cause a loss of vacuum.

Basically he keeps it as cold as possible even during and after its been washed etc. Since SW has started doing this he has had no explosions! (His walls and cieling thank him... so does his wife!) All of SW's explosions can be tributed to SW leaving the bromo at room temp by accident and forgetting about it after washing it or to accidently flushing the toilette at the wrong time.