Re: [Fwd: Re: [CH] news item: El Paso Pepper Producer (chipotles)]

T. Matthew Evans (tmattevans@yahoo.com)
Mon, 5 Apr 2004 16:22:59 -0700 (PDT) 

Peter and AndyB --

Actually, I don't think that the article is referring to hydrogen peroxide
being mixed with another acid -- otherwise, I don't think that they would refer
to it as "peroxide acid".  Here's my thought -- when hydrogen peroxide (a thick
syrupy liquid) is mixed with water (like the hydrogen peroxide you buy at the
drugstore), it forms a weak acid.

Hydrogen peroxide has a dissociation constant (Ka1) of about 2.4e-12, meaning
that when mixed with water, it loses some of its hydrogen ions.  These stray
hydrogens lower the pH of the mixture (remember, pH = -log[H+]) and viola,
you've got a weak acid.  I just did some "back of the envelope" calculations,
and I think that the pH of store-bought hydrogen peroxide should be about 5.8
-- less than seven.  It would be interesting if someone with a pH meter could
check this -- my number should not be exact because I don't know the actual
process used to make the peroxide (e.g., 3% by mass or by volume?) and I did
not take into account vapor equilibrium (i.e., there is a constant exchange of
chemicals across the free surface of the peroxide).

Remember, I'm not really a dilute solution chemist, I just play one on the
Internet.

Matt

--- AndyB <barnhart@mfire.com> wrote:
> 
> 
> -------- Original Message --------
> Subject: Re: [CH] news item: El Paso Pepper Producer (chipotles)
> Date: Mon, 05 Apr 2004 17:30:13 -0400
> From: AndyB <barnhart@mfire.com>
> To: Peter G <peter.g@telus.net>
> References: <40704338.6070700@telus.net>
> 
> Peter,
> 
> Hydrogen peroxide is a common oxidizer/antiseptic.  In some circumstance,
> it can be combined with an appropriate acid for both cleansing and
> sterilization purposes.  E.g., see
> 
>    http://www.megaconcentrate.com/cipcleaners.htm  - "CIP acid"
> 
> AndyB
> 
> Peter G wrote:
> 
> > Hi Folks,
> > 
> > here's an interesting news item ran across while searching for things 
> > fungal .
> > 
> >    Red-Hot Ideas: El Paso Pepper Producer
> >
>
http://www.newspapertree.com/newsletter.ssd?section=feature&c=712434d153474098
> 
> > 
> > 
> > any chemists out there who can explain whatever they're calling 
> > "peroxide acid"
> > might be? any contraindications?
> > 
> > regards
> > peter g
> > 
> > 
> > 
> > .
> > 
> 
> 
> 
> 


=====


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