10.5 Catalytic reactions 5.2 type of catalysis ypes Definition Examples )Homogeneous The catalyst is present Hydrolysis of sucrose with inorga in the same phase as acid catalysis the reactant NO2 catalyzes the oxidation of so2 2)Heterogeneous The catalyst constitutes Haber s process for ammonia synthesis catalysis a separate phase from contact oxidation of sulphur dioxide the reaction system ydrogenation of alkene, aldehyde, etc Reaction catalyzed 3)Biological/ Hydrolysis of starch in stomach with with biological enzyme catalysis the aid of diastase catalysts: enzyme
5.2 type of catalysis Types Definition Examples 1) Homogeneous catalysis The catalyst is present in the same phase as the reactant. Hydrolysis of sucrose with inorganic acid. NO2 catalyzes the oxidation of SO2 2) Heterogeneous catalysis The catalyst constitutes a separate phase from the reaction system Haber’s process for ammonia synthesis; contact oxidation of sulphur dioxide; Hydrogenation of alkene, aldehyde, etc. 3) Biological / enzyme catalysis Reaction catalyzed with biological catalysts: enzyme Hydrolysis of starch in stomach with the aid of diastase 10.5 Catalytic reactions
10.5 Catalytic reactions 5.3 General characteristics of catalyzed reactions 1)Catalyst takes part in the reaction (CH3)3COH-)(CH3)2C=CH2+H2o without catalyst: k=4.8 x 10 4 exp(-32700/msI with HBr(g) as catalyst: k=9.2 x 10 2 exp(-15200/T)dm3 mol-ls-I 15200 92×102expl k 32700)41×103 48×104exp T
5.3 General characteristics of catalyzed reactions 1) Catalyst takes part in the reaction. (CH3 ) 3COH ⎯→ (CH3 ) 2C=CH2 + H2O without catalyst: k = 4.8 1014 exp(-32700/T) s -1 with HBr (g) as catalyst: kc = 9.2 1012 exp(-15200/T) dm3 mol-1 s -1 23 14 12 4.1 10 32700 4.8 10 exp 15200 9.2 10 exp = − − = T T k kc 10.5 Catalytic reactions