1.
CH3C(=O)OH+R1OHH+R2C(=O)OEtCH_3\text{—}C(=O)\text{—}OH + R_1OH \xrightarrow{H^+} R_2\text{—}C(=O)\text{—}O\text{—}Et

R1R_1 and R2R_2 can be: