２．触媒の分類と触媒反応 Type of catalyst and catalytic reaction 触媒の分類 Type of catalyst 均一系触媒 homogeneous catalyst 反応物、生成物と同じ相例：錯体触媒、分子触媒液相均一系触媒も液体反応物＋触媒 reactant + catalyst 不均一系触媒 heterogeneous catalyst 相が違うもの例：固体触媒触媒層担持触媒 (活性成分＋担体) active component + support 無担持触媒反応物生成物 1 均一系触媒と不均一系触媒 Homogeneous and heterogeneous catalysis 均一系触媒 homogeneous H L S H2 L Rh Cl H C2H4 H Cl S L Cl CH2CH3 L Rh Rh L H H L Rh L CH2=CH2 Cl L S L=PPh3 S=溶媒 C2H6 不均一系（固体）触媒 heterogeneous H2 H H C2H4 H H CH =CH 2 2 CH3 H CH2 C2H6 均一系触媒および不均一系触媒によるアルケンの水素化反応. 千鯛眞信、市川勝、均一触媒と不均一触媒入門、丸善、1983． CO酸化触媒 CO oxidation catalyst 気相拡散気相拡散 O2 CO 気相拡散解離吸着表面拡散 CO2 分子状吸着表面反応金属触媒 metal cat. 担体 support 生成物脱離生成物吸着種 2 触媒反応のエネルギー過程 Energy profile of catalytic process 活性錯合体ポテンシャルエネルギー Ehomo 吸着活性錯合体反応物 Ead Es -Had -H 吸着反応物生成物 Ede 吸着生成物反応軸 -Had：吸着熱 -H ：反応熱 Ead：吸着の活性化エネルギー Es：表面反応の活性化エネルギー Ede：脱離の活性化エネルギー Ehomo：気相反応の活性化エネルギー The Haber-Bosch process step-by-step N2 + 3H2 → 2NH3 In the Haber-Bosch process nitrogen (white) reacts with hydrogen (blue) on an iron surface to then form molecules of ammonia which are released from the surface. This reaction, which extracts nitrogen from air, is an important step in the production of artificial fertilizer. http://nobelprize.org/nobel_prizes/chemistry/laureates/2007/info.pdf 3 触媒反応のエネルギー過程 Energy profile of catalytic process Non-catalytic Catalytic Nad+3Had An energy diagram showing the progression of the reaction from the reactants N2 and H2 to the product NH3. Energies are given in units of kJ/mol. (Adapted from Ertl 1983) N2 + 3H2 → 2NH3 1 N2 and H2 molecules approaching to the surface 2 Hydrogen molecule immediately dissociates 3 Nitrogen molecule adsorbs Whether nitrogen reacts in its molecular or atomic form? http://nobelprize.org/nobel_prizes/chemistry/laureates/2007/info.pdf 4 N2 + 3H2 → 2NH3 5 Reaction between N and H atoms 6 Reaction between NH and H atom 7 Reaction between NH2 and H atom 8 Desorption of NH3 NH3 ↔ NH2 + H NH2 ↔ NH + H NH ↔ N + H NH2 + D ↔ NH2D NH + 2D ↔ NHD2 N + 3D ↔ ND3 5