The esterification equilibrium

Exercise 8

    

Artificial apple flavor is due to a saturated aliphatic ester with the molecular formula $C_9H_{18}O_2$ 1) Hydrolysis of this ester gave two organic compounds $A$ and $B$. Write the general equation for the hydrolysis of an ester and say how we can increase yield. 2) A is oxidized by dichromate in acidic medium to give a compound $A_1$ which reacts with DNPH, but not with the Schiff reagent. Find the chemical functions of $A_1$, $A$ and $B$ 3) The molar mass of $A_1$ is $58\frac{g}{mol}$ . Find condensed structural formulas of $A_1$ and $A$ 4) Molecule $B$ contains a single branching, but is not chiral. Find the stylized formula of $B$ 5) Write a stylized formula of the ester and its name

1) $R_1COOR_2$ $+$ $H_2O$ $\leftrightarrows$ $ R_1COOH$ $+$ $R_2OH$ The added water increases the yield of hydrolysis. 2) $A_1$ is a ketone $A$ is a secondary alcohol $B$ is a carboxylic acid 3) General molecular formula of $A_1$: $C_nH_{2n}O$ $M_{A_1}$ $=$ $58$ $58=12n+2n+16$ $n=3$ Molecular formula of $A_1$ : $C_3H_6O$ $A_1$ is propanone $CH_3COCH_3$ $A$ is isopropanol $CH_3CHOHCH_3$ 4) $B$ should contain 6 carbon atoms, only one formula is possible: It is 2-ethylbutanoic acid 5) It is methylethyl-2-ethylbutanoate (isopropyl-2-ethylbutanoate)