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Hazard Predictions

• Corrosive: Reaction products may be corrosive
• Flammable: Reaction products may be flammable
• Generates heat: Exothermic reaction at ambient temperatures (releases heat)

Alkali and alkaline earth metals perform stepwise one-electron reductions of esters, creating reactive radical intermediates (E. M. Kaiser, Synthesis, 1972, (8), p. 391-415). In the presence of proton sources (esp. alcohol solvents), the reaction produces flammable alcohols and corrosive alkoxides (Bouveault-Blanc reduction) (L. Bouveault, G. Blanc, Comptes rendus. 1903, 136, 1676).

When proton sources are not available, highly active metals can reduce carboxylate, sulfonate, sulfonic, and phosphate esters to carboxylate, sulfonate, sulfonic, and phosphate salts, respectively, and highly basic metal alkyls. Highly reactive radical intermediates are formed during these reactions (A. G. M. Barrett, P. Prokopiou, D. Barton, R. B. Boar, J. F. McGhie, Chemical Communications, 1979, p. 1173; G. W. Kenner and N. R. Williams, J. Chem. Soc., 1955, p. 522-525; G. W. Kenner and M. A. Murray, J. Chem. Soc., 1949, p. S178-S181; S. C. Welch and M. E. Walters, J. Org. Chem., 1978, Vol. 43, No. 25, p. 4797-4799).

Alkyl sulfates can behave as alkylating agents in a similar way to alkyl halides, and react more vigorously. Alkyl halides form pyrophoric mixtures with active metals, and alkyl sulfates may be similarly hazardous (McCormack, W. B. and Lawes, B. C. 2000. Sulfuric and Sulfurous Esters. Kirk-Othmer Encyclopedia of Chemical Technology. (Online)).