Preparations of High Surface Aluminophosphates from Trialkylphosphates and EtAlCl[2][]



Jan Podhorsky^1,2, Zdenek Moravec^1, Jiri Pinkas^1,2

^1Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, Brno CZ-61137,
Czech Republic

^2CEITEC Masaryk University, Kamenice 5, Brno CZ-62500, Czech Republic

327941@mail.muni.cz



Aluminophosphates are structurally diverse compounds containing Al-O-P bond pattern through the
whole structure. Since their introduction in 1982 [1], porous tailored aluminophosphates have found
growing attention due to their applications as molecular sieves, catalyst carriers, and catalysts.
Among various methods, non-hydrolytic syntheses using trialkylphosphates was showing promising
results [2].


In our work, we focused on reactions of ethylaluminium dichloride with trimethyl- (TMP), triethyl-
(TEP), triisopropyl- (TiPP), and tributylphosphate (TBP). All reactions were carried out under
inert atmosphere. We have tested various reaction conditions, investigated reaction mechanisms, and
processed obtained xerogels into materials. Various processing conditions were investigated, as
well as influence of templating.


After calcination at 300 °C, we obtained amorphous aluminophosphates. Specimens obtained from TMP
and TEP xerogels exhibited high surface area (up to 468 m^2 g^-1) provided by small mesopores.
Higher calcination temperatures lead towards decrease of surface up to zero at 600 °C. Hydrothermal
processing at 200 °C in an autoclave provided non-porous microcrystalline berlinite AlPO[4].


References

[1] Wilson, S. T.; Lok, B. M.; Messina C.A.; Cannan T.R.; Flannigen E.M.  J. Am. Chem. Soc. 1982,
104, 1146 –1147.

[2] Pinkas J.; Wessel H.; Yang Y.; Montero M.L.; Noltemeyer M.; Fröba M.; Roesky H.W. Inorg. Chem.
1998, 37, 2450-2457.



The financial support by CZ.1.05/1.1.00/02.0068 and CZ.1.07/2.3.00/30.0037 is gratefully
acknowledged.