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By DFT calculation, we found that acid-catalyzed carboxylic acid esterification and ester hydrolysis are brief two-step reactions. First, the carboxylic acid hydroxyl-oxygen or ester alkyl-oxygen is protonated, which generates a highly active acylium ion. The protonation requires an activation energy (Ea) of 4-10 kcal mol(-1), and is the rate-controlling step of the esterification or hydrolysis. Sequentially, the acylium ion spontaneously reacts with two alcohol or two water molecules to form a neutral product molecule; this is a trimolecular reaction. The acylium ion is the highly active intermediate shared by esterification and hydrolysis. ESI-MS data for several typical carboxylic acids confirmed that their acylium ions are easily generated. For 2,4,6-trialkylbenzoic acid and its ester, the two unsubstituted carbons in the benzene ring are very easily protonated, and we have thus revealed the root of the success of Newman's method. Based on these results, the popular esterification and hydrolysis mechanism in organic chemistry textbooks is incorrect.

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Summary In this study, the metallurgical melting Mg‐10wt.%Ni (Mg10Ni) alloy is firstly modified by high‐energy ball milling (HEBM) and then surface catalysts expanded graphite (EG) or MoS2 or EG‐MoS2 are introduced to prepare Mg10Ni‐M (M = EG, MoS2, and EG‐MoS2) composites. The effects of surface catalysts on hydrolysis hydrogen generation of HEBM Mg10Ni alloy are comprehensively investigated. Their kinetics, rate‐limiting steps, and apparent activation energies are investigated by fitting the hydrolysis curves at different temperatures. The results indicate that the total hydrogen generation capacities of prepared Mg10Ni‐M (M = EG, MoS2, and EG‐MoS2) composites are 200, 170, 674, and 720 mL·g−1 within 1 minute at 291 K. The capacity and yield of Mg10Ni are 500 mL·g−1 and 56% within 15 minutes. The surface catalysts EG or MoS2 or EG‐MoS2 can distinctly elevate the initial H2 produce rate and promote the complete hydrolysis process. The highest capacity and generation yield within 15 minutes are 740.8 mL·g−1 and 91% obtained by HEBM Mg10Ni‐EG‐MoS2 composite at 291 K. The surface catalysis can promote high generation yield of Mg10Ni alloy in a short time.

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