Chlorine dioxide

The chlorine dioxide used in the sachets described by Pat
Weaver-Meyers at the last ALA Annual Meeting is not explosive like
the chlorine dioxide most people have heard of.  Its properties have
been radically changed.  On March 2, 1998, I took part in a
conference call with Tim Wildman, one of the inventors of the
sachet, and Walter Hardy, microbiologist and program handler for the
sachet, and they explained the history of the invention and its
development.  (Walter Hardy has 20 years' experience with chlorine
dioxide, the last eight years of which have been in food and
beverage research.)  At that time, the EPA was making noises that
indicated a possible approval in the fall of 1998, but that has
apparently not happened.

Tim Wildman and Walter Hardy explained that the chemical properties
of the compound had been altered to make it much less reactive, but
still effective.  I didn't press them for details, because I know
that some of them are trade secrets, and I probably wouldn't have
understood them anyhow.  But I did understand that it is inert until
the relative humidity reaches a level that encourages mold growth,
and then it vaporizes only fast enough to kill the mold, and quits
when the RH falls.  Pat's paper will probably contain a few more
details.  Publication has been delayed indefinitely, however,
because the Journal of Academic Librarianship, to which it was
submitted, has been bought by a European publisher, and is being
moved to Europe.

If the product were on the market now, skeptical chemists could buy
a sachet and test the properties they suspect are dangerous.  Until
then, I would like to ask everyone to withhold judgement.  As soon
as the product comes on the market, I will announce it in the Abbey
Newsletter.

In the meantime, people had better get used to the concept of
compounds with changed properties.  I just received a newspaper
clipping today about research at Carnegie-Mellon University that has
resulted in a "tamed" hydrogen peroxide (H2O2), normally an
aggressive bleach and oxidizing agent with many commercial and
industrial uses, including the bleaching of wood pulp.  The
inventor, chemist Terry Collins, worked on his invention for 20
years, in an effort to find an environmentally more benign compound
containing fewer elements, because this will discourage formation of
toxic pollutants.  The more elements in a compound, the more trouble
it can make when it gets out into the environment.

He calls his new approach "green chemistry," and has reason to
believe that this will be the new direction for companies that
introduce new industrial compounds, but do not want to face the
fines and penalties that come with appearance of toxins like dioxin
in their effluent.  What motivates him, however, is not the threat
of fines and penalties, but a desire to make the world safer.  One
of his long-time preoccupations is disinfection of drinking water.

What he did was to build a simple catalyst (iron) into the H2O2
molecule, with the aid of a ligand (scaffolding) made up of
nitrogen, oxygen, hydrogen and carbon atoms.  The catalyst separates
one oxygen off, and it oxidizes the next thing it sees; but
apparently the whole molecule does not take part in the reaction. It
is a selective reaction, which takes place at room temperature and
ordinary pressure, is not corrosive and requires no special
handling.  (Get the article yourself--it's in the Pittsburgh
Post-Gazette, in the Science & Environment section, headlined "A
'green' alternative to chlorine," or contact Terry Collins at
Carnegie-Mellon University.)

I have gone into detail about the hydrogen peroxide news in order to
make the point that it is no longer possible to be certain of the
properties of a familiar compound like chlorine dioxide, unless you
know it has not been altered.

Ellen McCrady, Editor
Abbey Publications
7105 Geneva Dr.
Austin, TX 78723
512-929-3992
Fax:  512-929-3995

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                  Conservation DistList Instance 12:79
                  Distributed: Tuesday, April 6, 1999
                       Message Id: cdl-12-79-001
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