1. CH3CH2COOH + Ca(HCO3)2 -> CH3CH2COOCa(CH3CH2COO) + 2H2O + 2CO2 (X1 - кальциевая соль пропионовой кислоты).
2. CH3CH2COOCa(CH3CH2COO) + 2HCl -> 2CH3CH2COOH + CaCl2.
3. 2CH3CH2COOH --(t°, H2SO4)--> CH3CH2COOCH2CH3 + H2O (X1 - этилпропионат).
4. CH3CH2COOCH2CH3 + CH3MgBr -> (CH3)2C(OMgBr)CH2CH3 --(H2O)--> (CH3)2C(OH)CH2CH3 (X1 - 2-метилбутан-2-ол).
5. CH3CH2COOH + Ca(OH)2 -> (CH3CH2COO)2Ca + 2H2O. (CH3CH2COO)2Ca + 2H+ -> 2CH3CH2COOH.
6. CH3CH2COOH + SOCl2 -> CH3CH2COCl + SO2 + HCl.
7. CH3CH2COCl + CH3CH2MgBr -> CH3CH2COCH2CH3 + MgBrCl (X1 - пентан-3-он).
8. CH3CH2COCH2CH3 + KMnO4 + H+ + t° -> CH3COOH + CH3CH2COOH (X2 - пентан-3-он, X3 - уксусная и пропионовая кислоты).