White Yeti - 15-1-2014 at 09:43
Acid and base catalysis is the key to many organic reactions. Ordinarily, you can use a strong dehydrating acid or base to catalyze esterifications,
enolizations, hydrolysis, but this limits the range of reactions that can be carried out. Additionally, these acidic and basic reagents make workup
more lengthy and complicated resulting in reduced yields.
It's about time to demystify zeolite and alumina catalysis so that the home scientist can take advantage of higher reaction yields and selectivity.
Firstly, anyone with experience regarding the preparation of zeolite catalysts is welcome to share any procedures. There are many commercially
available starting materials for solid catalyst preparation. To name a few:
silica gel
diatomite
zeolite (artificial or natural)
ion exchange resins
sodium silicate
sodium aluminate
aluminium oxide
Here is a procedure for making a specific kind of zeolite (zeolite ZSM5)
http://education.mrsec.wisc.edu/310.htm
I would have shared some additional resources if it weren't for Elsevier's SkyNet system.
Of particular interest is the development of zeolite acid catalysts. One way to make these acid catalysts is to exchange silicon cations with
aluminium cations. The extra positive charge necessary for charge balancing is provided by a proton, making the zeolite acidic.
Another method I read about was to let the zeolite absorb ammonium ions. Once it is saturated, the zeolite is pyrolyzed to remove the ammonia and
leave acidic protons.
Either way, I could not find a detailed procedure for catalyst preparation. I was wondering perhaps some people here would be interested to learn how
to prepare these catalysts, and perhaps some people have already developed working procedures.
The preparation of these catalysts is not simple, but it isn't beyond the means of a home chemist either.
Any ideas?
plante1999 - 15-1-2014 at 14:10
https://drive.google.com/file/d/0B3q9ENdw06FQaHIxT1pXbThjbVU...
mnick12 - 26-1-2014 at 10:50
Are you looking for a particular catalysts? Have a reaction in mind, or are you more interested in the preparation of these compounds? I don't have
any experience with zeolite synthesis but I toyed around with various metals supported on silica based substrates. They were all bunk, as far as I
could tell, but that may have been due to lab restraints.
bfesser - 26-1-2014 at 17:37
<strong><a href="viewthread.php?tid=10704">Cu/SiO2 a cheap versatil hydrogenation catalyst?</a></strong>
JAVA - 28-1-2014 at 17:15
They can be made by the procedure of Union Carbide, the preparation of Pb-ZSM have a US patent. They use sodium silicate, aluminium sulfate and much
NaCl. This works but it's tuff, a dusty asbestos-like sticky substance comes free, the floor was covered with dust and it took me nearly two weeks
non-stop to make it, including the ion exchange from Na-ZSM 5 to NH4-ZSM 5 to Pb-ZSM 5, also you need high pressure otherwise the zeolite is not stong
enough. I should go for a more acidic zeolite then 5 and stop at the NH4-stage for your purposes.
Sounds like work
[Edited on 29-1-2014 by JAVA]
JAVA - 30-1-2014 at 12:20
Source for the preparation of zeolites:
"US patent 3,702,886"
Further reading about ion exchange "Catalysis, crystalline Aluminosillicates: characterization of Intermediate pore - size zeolites by the constant
Index. Journal of catalysis 67, 218 - 221 (1981)"