[Histonet] Butyl alcohol

[John Kiernan]

Dear Todd Krueger,
 
There are three isomeric butyl alcohols (primary, secondary and tertiary) with different physical properties. and different uses in histology for primary and tertiary. 
 
I have used tertiary butyl alcohol (= t-butanol = 2-methylpropan-2-ol) a few times for processing into paraffin. It mixes with with both water and wax. It boils at 83C so it's slightly less of a fire hazard than ethanol. It doesn't form explosive peroxides with long storage, which makes it safer than dioxane and tetrahydrofuran, two other "universal solvents" that have been used for combined dehydration and clearing. 
 
t-Butanol doesn't have an offensive odour, but it is solid below 25C, which is inconvenient, and it's quite a bit more expensive than more commonly used solvents such as ethanol, isopropanol and xylene. t-Butanol was introduced as a combined dehydration and clearing agent by Larbaud (1921) Compt. Rend. Acad. Sci. 172:1317-1319. It is used more in plant than in animal histology. 

Primary butyl alcohol (n-butanol) is liquid at ordinary temperatures. It is only partly miscible with water, but miscible with ethanol-water mixtures and with paraffin. It has been recommended for transitioning to wax in procedures claimed to reduce hardening of wood (Zirkle 1930, Science 71:103-104) and insect specimens (Stiles 1934, Stain Technol. 9:97-100).  Freeze-substitution into n-butanol can be followed by paraffin embedding because this alcohol is a liquid from -90 to +117C.  I haven't tried any of these methods.
 
Another use of n-butanol is in dehydration of sections stained with dyes that are easily extracted by water or water-ethanol mixtures. I have lots of experience in this area.  A major disadvantage of n-butanol, for any application, is its vapour. It doesn't smell nasty but it makes you cough. 
 
John Kiernan
Anatomy, UWO
London, Canada
= = =
----- Original Message -----
From: "Krueger, Todd" <Todd.Krueger <@t> bsci.com>
Date: Wednesday, March 3, 2010 17:08
Subject: [Histonet] Butyl alcohol
To: histonet <@t> lists.utsouthwestern.edu

> Has anyone tried using butyl alcohol as a dehydrating and 
> clearing agent
> on there tissues? What are some pros and cons people have experienced
> with using Butyl alcohol?
>  
> Todd Krueger
> 
> HTL(ASCP)CM
> 
> Boston Scientific
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