Different CAS #

[easttn]

Im looking around the MSDS sheets of different pool products and figure out they name the exact same chemical different names. The only way to distinquish if they are the same is the CAS#. However I find some with different CAS#'s which would mean they are of a different makeup.

Dichlor
02893-78-9 Sodium dichloro-s-triazinetrione
51580-86-0 Sodium Dichloro-s-Triazinetrione Dihydrate

Polyquat
31075-24-8 Poly (oxyethylene(dimethyliminio)ethylene-(dimethyliminio)ethylene dichloride)
31512-74-0 Poly [oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride]

Can someone tell me the difference between the two?
I assume in the case of Dichlor, one is Dihydrate and the other is Anhydrous?
Looks like one poly is in parenthesis and the other is in square brackets.

 

[chem geek]

For the Dichlor, the first one is anhydrous which means it does not contain water while the dihydrate contains two water molecules with each Dichlor molecule. They are each identical when added to water so the only practical difference is the weight difference due to the differing water content. In practice, you almost always find Dichlor as dihydrate because the anhydrous is a Class 3 oxidizer (similar to Cal-Hypo that is > 50% in concentration) and as such is a greater fire hazard (see this link -- not flammable per se, but fire can be sustained -- see the videos in this link regarding Cal-Hypo). Sometimes the MSDS will explicitly list the water separately as in 86% Dichlor and 14% Water, but this is actually the same as 100% Dichlor dihydrate.

As for the Polyquat, the two CAS numbers are synonyms for the same chemical. I'm not sure why the same chemical has two CAS numbers, but it does.

 

[easttn]

Thanks for the explanation.

I believe the ones that said 02893-78-9 Sodium dichloro-s-triazinetrione were the lower percentage dichlor products (58.2% and 63.05%). Both have added stuff like clarifiers, copper and such while the ones that said 51580-86-0 Sodium Dichloro-s-Triazinetrione Dihydrate were the 99%/56%AvailChlorine products. I have yet to find a pure anhydrous product (99%/64% AC) probably because like you say, its more of a hazard.

 

[chem geek]

So Available Chlorine is different than the percentages I was giving you which were weight percentages of ingredients (i.e. Dichlor itself). The Available Chlorine for pure Dichlor anhydrous is 70.906*2/219.95 = 64.5% while for pure Dichlor dihydrate it is 70.906*2/255.98 = 55.4%. So your 58.2% would be 90% Dichlor anhydrous while your 63.05% would be 98% Dichlor anhydrous. Typical Dichlor dihydrate is 99% pure so is 54.8% (around 55%) Available Chlorine. I don't know why they would say "56%" since that technically could not be true.

 

[easttn]

Ok good deal. They display 56% available chlorine on dichlor dihydrate when you go shopping around per say. Thats not true like you say but thats what they say. As far as the 58.2% and 63.05% products they dont tell you on the box. You have to dig around for that information.

 

[easttn]

So your 58.2% would be 90% Dichlor anhydrous while your 63.05% would be 98% Dichlor anhydrous.

Oh wait a minute. I think somethings gotten mixed up.
58.2% and 63.05% is the percentage of anhydrous dichlor in the products.
http://www.kellysolutions.com/ak/sh...hemical_Name=Sodium+dichloro-s-triazinetrione
Available Chlorine should be somewhere in the 38% range for both of them.