Yeah, old thread - I know...but!
The thing I love about nexus (esp to a non chemistry person) is that when something goes "wrong", someone always seems to have been there before you!
So I got this too. There is another thread I couldnt find which also had this pink thang happen. Maybe I will find later.
I have no idea about why's or whats so let me just report what happened.
Essentially:
Started 5g DHH HCl ex rue / vinegar / ammonia route (VDS)
Added 200ml vinegar 5%
Added 4g zinc
Added 1% HCl to drop pH to ~2
Stirred 9 hours.
Went from cloudy green coloured liquid to clear with zinc granules very visible
Left 6 hours settling still slight bubbling
Decant 2x and filtered through 3mm diatomaceous earth
dH2O wash zinc and filter
Solution at 280ml
Bright clear lumo yellow filtrate
On stirring, dropwise add 12% ammonia
Ph start @ < 3
Continue adding (white clouds on each drip almost immediately )
Clouds take longer to disperse as ph rises
Around 4.8+ starts losing clear transparency, clouding
Around ph6 losing nice Lumo yellow -- changed now to pinky brown tint and not as clear
At ph 7 quite cloudy liquid still clouds noticeably on drip
@ pH7.2 completely opaque now but still clouds on drip at surface
The thing is... its really PINK!!
The liquid is a darkish but clear pink/rosé color and the precipitate is lighter, giving a light pink appearance
Bluish uv glow on top surface edges sort of visible in daylight
Slight clearer layer forming at the top
White particulate precipitate visible if stirring slowed
8.7 liquid now getting darker less cloudy (clearer)
8.9 cloudy again, more particulate precipitation starting now
9.3 seems no more drip -> clouds.
Stopped stirring to let it settle before resuming the dripping
Still clouding increases
Resumed stirring
~9.5 ph change is now very slow. 8-10 drips per .01 ph
At 9.67 stopped stirring and adding. Removed magnet and ph meter to let it settle for filtering thru buchner vaccuum
Precipitate is very fine but PINK!!
Actually tested Marquis reagent - green!
Bioassay, as far as I can tell: THH My experience is limited but was pretty much not harmaline! Taste, neutral.
Started 5g DHH, yield 2.256g. Pretty pathetic, not sure what the heck happened here!
Tried more Ammonia 25% to up pH > 11. Nothing dropped out at all. Stayed darkish but clear rose-wine color.
*EDIT: found the other
thread!
Found this comment and seems it may be relevant: (just to note I have done this zinc reduction about 4 times now and this was the only time this happened, usually its pretty much white THH)
Synkromystic wrote:I've done the zinc/acetic acid thh reduction a few more times since I encountered the purple/pink ''stuff'', and I have not gotten any pink at all. I've reduced the time of the zinc reaction drastically and I attribute this to the improvement.
When I got the purple/pink stuff I had done the reaction over the course of a few hours, then let it sit around for about a day before i filtered and based. But now I do the reaction with in minutes, filter quickly then base. Then redissolve the alks in acetic acid and let the excess zinc settle out. Then i filter again and add base......then filter and wash alks with water numerous times.
merkin attached the following image(s):
thh_01.jpg
(1,791kb) downloaded 80 time(s). thh_02.jpg
(1,875kb) downloaded 82 time(s).