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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: atta001 on May 30, 2005, 11:33:57 PM

Title: Drying of Alcohols.
Post by: atta001 on May 30, 2005, 11:33:57 PM

Hi All,

I have got 1-Butanol with me. The specifications on it indicate that the alcohol content is either 99% or higher. Rest is water  All I want is anhydros alcohol. I have CaCl2 with me but I have come to know it forms byprodcts. So which drying agent do you people recommend for drying 1-Butanol. Please also tell me the quantity of the drying agent required for a given sample of alcohol. I will be grateful.

Regards,

Atta.

Title: Re:Drying of Alcohols.
Post by: Mitch on May 30, 2005, 11:47:42 PM

Look into usining molecular sieves, I don't know the exact prep.

Title: Re:Drying of Alcohols.
Post by: lemonoman on May 31, 2005, 01:42:52 AM

I wonder if ordinary anhydrous sodium sulfate would work?  It's always seemed unreactive with organic compounds, and dries things nicely...

Title: Regeneration of Drying Agents.
Post by: atta001 on May 31, 2005, 02:37:23 AM

I wonder how to regenrate used or hydrated Sodium Sulfate. Any assistance.

Title: Re:Regeneration of Drying Agents.
Post by: Garneck on May 31, 2005, 03:02:17 AM

Quote from: atta001 on May 31, 2005, 02:37:23 AM

I wonder how to regenrate used or hydrated Sodium Sulfate. Any assistance.

Put it in an oven.

Title: Re:Drying of Alcohols.
Post by: xiankai on May 31, 2005, 05:54:35 AM

is it possible to use conc. H2SO4 to dry the alcohol

all i know is that its used for dehydrating the water formed when making esters

Title: Re:Drying of Alcohols.
Post by: Dude on June 04, 2005, 12:27:02 PM

It's covered in "Vogel's textbook of practical organic chemistry", a must have for anyone starting research involving organic chemistry preparations.

Title: Re:Drying of Alcohols.
Post by: movies on June 05, 2005, 11:41:16 PM

Molecular sieves are probably the easiest way.  There are tables indicating which pore size will be best for selectively absorbing water in the presence of butanol.  My guess would be 3 angstrom.  They will need to be activated prior to use, so put some in a beaker in a drying oven for about 24 hours.  I prefer the pellet form (as opposed to the powder) for drying reagents.

Magnesium sulfate is a good alternative too.  It tends to work better than sodium sulfate, but other polar things tend to "stick" to it as well.  In this case, however, you have a truckload of butanol so you probably don't care too much about the percent recovery.

Title: Re:Drying of Alcohols.
Post by: Mitch on June 06, 2005, 12:28:54 PM

Powdered mag sulfate will do that. The crystalline stuff will tend not to pull other polar agents out.