Eclectic - 2-9-2010 at 17:24
I have some technical grade propylene carbonate I'd like to purify as much as possible without resorting to vacuum distillation. Does anyone have a
comprehensive list of substances absorbed and excluded by 5A and 13X mol sieves? In particular: propylene glycol, propylene carbonate, ethylene
glycol.
chemrox - 4-9-2010 at 21:11
On a hunch I tried Journal of Chem Ed and quite a few articles. This one showed a little promise.
Experiments for the Undergraduate Laboratory That Illustrate the Size-Exclusion Properties of Zeolite Molecular Sieves
AbstractHi-Res PDF[241 KB]PDF w/ Links[242 KB]Supporting InfoJason Cooke and Eric J. Henderson
Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
J. Chem. Educ., 2009, 86 (5), p 606
DOI: 10.1021/ed086p606
Publication Date (Web): May 1, 2009
Abstract
Experiments are presented that demonstrate the size-exclusion properties of zeolites and reveal the reason for naming zeolites "molecular sieves". If
an IR spectrometer is available, the adsorption or exclusion of alcohols of varying sizes from dichloromethane or chloroform solutions can be readily
demonstrated by monitoring changes in the intensity of the alcohol OH band in the IR spectra. It is also possible to qualitatively illustrate whether
solvents of varying sizes are able to enter the pores of different zeolites by observing the displacement of adsorbed nitrogen gas from within the
pores. The volume of evolved gas is considerable and can be measured if desired.
Keywords:Second-Year Undergraduate
Keywords:Inorganic Chemistry
Keywords:Hands-On Learning / Manipulatives
Keywords:Alcohols
If you want it I can post it in refs.
chemrox - 4-9-2010 at 21:17
As an aside I'm trying to run some Dieckman cyclizations in glycols and glycerol as green solvents. I probably won't be able to use metal alkoxides
for the bases but maybe CaH will work.
Eclectic - 5-9-2010 at 02:38
Thanks, I'd seen the abstract of that. The full PDF would be a usefull read.
I was hoping that 5A would admit propylene glycol and smaller, or that 13X would exclude propylene carbonate.
I'll probably just need to run some tests. Awaiting the 13X from Ebay.
Likely contaminates in tech propylene carbonate are water, propylene glycol, propylene oxide.