Ⅰ.CO2(g)+3H2(g) CH3OH(g)+H2O(g) ΔH1=-49.1kJ·mol-1
Ⅱ.2CH3OH(g) CH3OCH3(g)+H2O(g) ΔH2=-24.5kJ·mol-1
Ⅲ.CO2(g)+H2(g) CO(g)+H2(g) ΔH3
Ⅳ.2CO2(g)+6H2(g) CH3OCH3(g)+3H2O(g) ΔH4
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