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Napthalene, Naphtha, Naptha What is the Difference?

I don’t know what it is about napthalene.  Is it the fused rings, conjugated double bonds, distinct odor?  Not sure, but there is something about this chemical that I dig.  Maybe it is simply the Daffy Duck “pth” that can’t be avoided when saying the name. 

Napthalene is a polyaromatic hydrocarbon.  It is two benzene rings connected together look like a set of handcuffs.  The conjugated double bonds in the rings allow electrons to jump into excited states when the compound absorbs Ultra-Violet radiation.  The excited electrons release the extra energy as light.  Naphthalene’s light is bright purplish blue.   

 My husband is so sensitive to poison ivy and so desperate to get rid of its insatiable itch that he started using a harsh laundry soap bar called Fels Naptha on his skin post exposure.  He was told that the itch fighting ingredient in the soap was naphthalene.  It made sense given the name.  I might have looked into this fact when my child started breaking out with poison ivy.  Instead, after playing in the woods, I scrub him down with Fels Naptha like a set of greased stained cover-alls to avoid a rash.  Now that two years of use have gone by, it seems I should have probably looked into whether this chemical, described in its MSDS as harmful if absorbed through the skin, is the main ingredient in Fels Naptha Soap. 

There is little use for bar laundry detergent these days.  Hand scrubbing individual items of clothing on rocks or even wash boards seems to have fallen out of favor.  But there is a real cult of Fels Naptha followers.  Aside from the poison ivy suffers there are people, who presumably live nowhere near a grocery store, that make their own laundry soap.  They go about this by purchasing three different soaps (Fels, Borax and Arm and Hammer Washing Soap) and combining them.  I know, the logic is lost on me too!  Here is my favorite quote from one of these Fels Napthians lamenting about the soap’s formula change, “I used to use fels naptha to make my laundry soap, …but what’s the point of making your own soap if it is just as full of chemicals…”  Uhhh…oh forget it. 

These seekers of chemical free soap (?) might be happy to learn that Fels Naptha does not contain naphthalene.  It contains petroleum (also called naphtha) which is composed of a whole slew of chemicals.  The soaps formulation has changed since it was acquired by Dial Corporation and naphta is no longer listed among its ingredients.  Although it is not stated directly, the ingredient list hints to the fact that the soap contains lye.  That would eliminate poison ivy oil and, for that matter, any other fat in your skin. 

So there you have it, naphthalene, naptha, naphtha, now you know.

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