Calcium oxide (24 g) was dipped in 200 ml
of ammonium carbonate solution then the mixture
was stirred for 30 minutes at room temperature. After
filtration and drying at 112 0C till constant weight,
the dried solid was milled and sieved then calcined at
850 0C for 1.5 hrs. After cooling in a dessicator to
room temperature the base CaO is ready to use. High
temperature calcinations of CaO improved the
performance of the catalyst.