Author Topic: 15% peracetic acid  (Read 1897 times)

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Aunty

  • Guest
15% peracetic acid
« on: October 06, 2002, 01:31:00 PM »
15% peracetic acid, as called for in Chromic's excellent write up is widely used in the brewing industry as a sanitizer. Ironically, peracetic acid is rapidly replacing iodine based sanitizers which most brewing chem suppliers still carry. Aunty will make some calls tomorrow to double check that nothing else is included (surfactants, et cetera), but quickly perusing available MSD info shows nothing but 15% peracetic acid. Hope this is useful to somebee. These folks are mostly very friendly and would be shocked at the suggestion that there might be some clandestine use for any of thier products!

GC_MS

  • Guest
peracetic acid
« Reply #1 on: October 06, 2002, 01:42:00 PM »
Peracetic acid is rather stable, just keep it out of light and store it in a cool place. Peracetic acid is commercially available, but SWiM never bought it since it is a small effort to make it SWihimself. Actually, SWiM didn't know it was sold in the kind of stores you mentioned.
MSD info... Mass Selective Detector info? SWiM doesn't think that MSDs like reactive peracids as peracetic acid that much... Try iodometric titration, has always been used to check the peracid concentration. Furthermore, if the peracetic acid concentration is 15%, it should show something else as well, don't you think?   ;)

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Aunty

  • Guest
msds
« Reply #2 on: October 06, 2002, 02:01:00 PM »
"MSD info" = material safety data sheet. Gonna make some calls tomorrow re: purity. Just thought it might be handy to buy rather than wait a week for the peracetic to be ready. It's pretty cheap as Aunty recalls.

Chromic

  • Guest
Good info!
« Reply #3 on: October 07, 2002, 09:11:00 AM »
Homemade peracetic has been rather stable, storing well for up to 6 months in the fridge. It's not as stable as the hydrogen peroxide stored separately, but keeps well.

Great info! I hope it's adopted as a common cleaner.  :)

Rhodium

  • Guest
Preparation and stability of peracetic acid: ...
« Reply #4 on: October 07, 2002, 11:00:00 AM »
Preparation and stability of peracetic acid:

https://www.thevespiary.org/rhodium/Rhodium/pdf/peracid.pdf



75% of peracetic acid prepared from 90% H2O2 remains intact after storage at room temp for seven weeks. If 100ppm of sodium pyrophosphate was added, 93% of the peracetic acid kept for seven weeks.

Performic acid decays within days.

GC_MS

  • Guest
performic
« Reply #5 on: October 07, 2002, 03:11:00 PM »
When using the performic route, SWiM generates the performic in situ. If you prepare it in advance and allow it to stand for two hours without cooling, you'll notice the development of gas bubbles. SWiM assumes those bubbles are CO2 and indicate the decay of HCOOOH.

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terbium

  • Guest
CO2?
« Reply #6 on: October 07, 2002, 04:04:00 PM »
SWiM assumes those bubbles are CO2 and indicate the decay of HCOOOH.
Hmm, I would have assumed that the bubbles are O2.


Baseline Does Not Exist.

GC_MS

  • Guest
CO2
« Reply #7 on: October 07, 2002, 04:17:00 PM »
HCOOOH ---[unstable]---> H2O + CO2

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Rhodium

  • Guest
Make the solution beforehand
« Reply #8 on: October 07, 2002, 04:27:00 PM »
GC_MS: If you look at the graph in the article posted by me above, you will see that the concentration of performic acid is at its highest level one hour after mixing 30% H2O2 and formic acid.

GC_MS

  • Guest
true...
« Reply #9 on: October 07, 2002, 04:51:00 PM »
Yes, I know. In most articles, they make their performic half an hour - one hour in advance before using it. I also checked some of the references in the review pdf, and some of them were very interesting (difference in kinetics between 30% and 90% H2O2 etc etc). I usually mix my 98% HCOOH and 30% H2O2 for 5 minutes and slowly add my DCM. Allow to stir for a couple of minutes, followed by drop-wise adding one of my beloved phenyl-1-propenes. This never gave me any problems. I just extend my run time by one hour  :) .

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Rhodium

  • Guest
inverse addition?
« Reply #10 on: October 07, 2002, 04:55:00 PM »
You add the phenylpropene dropwise to the performic in DCM, and not the other way around? Do you experience a difference in yield by this inverse addition?

GC_MS

  • Guest
not really
« Reply #11 on: October 07, 2002, 05:27:00 PM »
Not really, no. It's just a matter of practical convenience. The performic is generated in situ while the phenylpropene is added drop by drop. The theory is that the generated performic reacts with the propenyl double bound as soon as it is formed. In my experience, the exothermic reaction is easier to control by adding the phenylpropenyl dropwise to a low concentrated performic acid solution. It is just my way of working with HCOOOH, the methods on your page work equally well - except for that acetone shit off course  :P .

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Rhodium

  • Guest
Do you use buffer? Are you adding sodium ...
« Reply #12 on: October 08, 2002, 02:22:00 AM »
Do you use buffer? Are you adding sodium carbonate directly to the peracid mix?

GC_MS

  • Guest
buffer
« Reply #13 on: October 08, 2002, 01:48:00 PM »
No, never used buffer when doing the performic. As I remember, typical yields were between 50-65% (ketone). Switched to peracetic later on.

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