Improvement of Lifetime Using Transition Metal-Incorporated SAPO-34 Catalysts in Conversion of Dimethyl Ether to Light Olefins

Table 2

Measured acidity during the ammonia temperature-programmed ammonia desorption.

Catalyst	Acidity: NH3 desorption amounts (mmol/g)
	Weak; 290–310°C	Strong; 460–500°C	Total amount
SAPO-34	0.3426	0.4466	0.7891
MnAPSO-34	0.3795	0.5013	0.8809
FeAPSO-34	0.4460	0.5100	0.9560
NiAPSO-34	0.5638	0.4959	1.0598