HI via KI+phosphoric, big stink, something wrong?

[superman]

100g batch,   flask on hotplate, connected to another flask via tubing. the second flask is just a water trap (the 1-way aquarium valves leaked like a sieve),   if suckback occurs the water will be sucked into this flask from a 50ml glass graduated cylinder, which contains 30ml H2O to catch the gas.

the 1-way valves didn't work so ive been forced to use this method, i know i run the risk of my water being sucked completely from the cylinder,   so i'm doing this outside and i'll be ready to add more water to the cylinder if it get sucked out.   this of course will leave me with diluted acid but i'll be concentrating it anyways and have accounted for the yeild loss.

now unless i misread shorty's method, this should be working fine,   but it stinks like a mother fucker(thus my decision to move outside), just wondering if i overlooked something.

EDIT: fuck it i'm tired.  will do it tomorrow with a condenser

[biotechdude]

This works perfectly for 100g

500mL reaction flask --> U-shaped receiving bend --> vertical condenser --> receiving flask with small volume of dH2O.

You will need a proper condenser with at least tap water cooling the jacket.  Further, add a small volume of water in the receiving flask to absorb HI(g).  Also, a damp tea towel over any leaks will absorb smelly fumes.  Dont fuck around with water traps, more trouble than their worth for little reactions.  Use a gas burner as a heat source, and keep in mind the majority of HI is produced as (g) after the water in the H3PO4 has evaporated off.  Stop the reaction when the collected HI is a dark red colour.  Then add a P-based recycler to clear the solution and ready it for further reactions...

[superman]

ahhh,   that's sounds much nicer    should i anticipate a problem with using a 250ml flask vs. 500ml??   i chose it because it's a thick wall pyrex,   the contents of the flask are at the 100ml mark.

thanks!

[superman]

ok i just fired it up as you suggested, the tip of the condenser is submerged in 30ml H2O in a 50ml beaker,   so there's about an inch of water.   but the HI gas was making it out of the flask.   my question is should i have a different recieving vessel/more water/some else,    or would i be abled to cover the ice bath that the beaker is sitting in with a wet rag without losing all my HI¿?

if i'm being over cautious let me know,    except last night this is my first encounter with this odour being so strong :/

[Scottydog]

Maybee use a filtering flask for the receiving vessel?

A condenser can bee attached to the receiving flask with a rubber stopper and a hose attached to the nipple on the filter flask. This hose can spiral up through a bucket of ice and bee long enough to go out a window, into a fume hood or another flask with activated charcoal/kitty litter?

Shouldn't bee too hard to remedy?

[superman]

god i wish i had one,   and i broke my other flask,  thus my resorting to the beaker

[WizardX]

Balanced Equation.

3 KI   +    H3PO4      ==>   3 HI   +   K3PO4

(3 x 166) +    98   ==>    (3 x 127.9)   +   212.3

498     +   98   ==>   383.7      +   212.3

596         ==>         596


Assuming your KI is anhydrous and not hydrated KI then, (100/166) = 0.602 moles of KI. Since the ratio of KI:H3PO4 is 3:1

Therefore 1/3 x 0.602 = 0.2 moles of H3PO4

Summary: 100 grams of KI + 19.6 grams of H3PO4

Dissolve 100 grams of KI in 500 mls of distilled water, then add 19.6 grams of H3PO4 with swirling. Allow to stand for 1-2 minutes. Then azeotropic distill this solution to get 57% w/w HI

[superman]

yes looks like a balanced equation there, and i do understand chemical equations as well as how to balance them,   but i'm ahead of you os,   i'm aready in the process of distilling over the HI to form the azeotrope in the receiving vessel, in this case a beaker containing containing 30mL(g) of water.   

did i miss something you were saying?

i'm worried that my receiver can't dissolve the HI fast enough and since the RXN takes a bit to calm down i want to be extra sure i'm not filling my lab (bedroom) with gasses that will fuck electronics, room and self up.   as well i want to make sure that a quick fix like a wat rag over the ice bath won't just waste all my acid

EDIT:  guess i should mention the rxn details for ya wiz,   i'm using reage LG KI,   appears dry,   always kept sealed.   and began with 85% phosphoric, from hydro store,   boiled to approx 90%.

i used argox's ratio,   100g ki : 100g 75% acid,   but accounted for the change in concentration, and used a bit excess acid to be sure

[biotechdude]

should i anticipate a problem with using a 250ml flask vs. 500ml??   i chose it because it's a thick wall pyrex,   the contents of the flask are at the 100ml mark.

That should be fine as the reactants dont bubble or go crazy.  Wouldn't load it up much more than that though. 

my question is should i have a different recieving vessel/more water/some else,my question is should i have a different recieving vessel/more water/some else,

When Swix was dreaming naughty things, he used the setup mentioned before with the vertical condenser.  The receiving vessel was a 1.25 Ltr glass bottle (like those ones they serve water in at restaurants).  For 100g KI and 100mL 86% H3PO4 reactions, only about 10mL of dH2O was added to the receiving bottle (enough to cover the base). 

The end of the condenser was just inserted into the opening of the bottle (good size match).  It wasn't jammed in tight and sealed, just placed in; and a damp washer wrapped loosely round the semi-fitted (on purpose) junction.

The problem with your setup is that you are submerging the end of the condenser into the water.  This is when suckback is a bitch.  Further, u need to give the HI(g) time and surface area so it can slowly absorbe into the water.  Thats why the 1.25 bottle worked well...

Also, if adequate cooling is used, most of the HI going into the receiving vessel is condensed already; so HI(g) loss is minimal.  And any that wants to escape, is quickly absorbed into the damp washer.

When the collected HI is dark blood red and its apparent the reaction has slowed considerably; turn it off and LET COOL.  Then measure 1mL (accurately) of your collected HI and weigh.  If <1.7g, distill off the weak HI until 127'C is reached and reweigh to ensure D1.7g at least. 

Conversely, Wizard X's advice is spot on; and moreso the correct way to do this reaction.

[superman]

[superman]

just an update, worked well, until the latex tubing melted,   guess two glass elbows connected via rubber would be the way to go?