Oxidation of aldehydes and ketones

Exercise 3

   

 

Butanone (methylethyl ketone, liquid, d = $0.81$) is obtained by hydration of but-1-ene followed by oxidation of the alcohol obtained predominantly. 1) What is the alcohol obtained predominantly? 2) Study the redox system of the oxidation of the alcohol by potassium dichromate in an acidic medium! 3) With $1\;m^3$ but-1-ene (gas, STP) is obtained $2.5\;L$ butanone. What is the yield of this process?

1) $CH_3CHOHCH_2CH_3$, butan-2-ol 2) $CH_3CHOHCH_2CH_3$ $-$ $2e^-$ $\rightarrow$ $CH_3C=OCH_2CH_3$ $+$ $2H^+$ $Cr_2O_7^{2-}$ $+$ $14H^+$ $+$ $6e^-$ $\rightarrow$ $2Cr^{3+}$ $+$ $7H_2O$ $Cr_2O_7^{2-}$ $+$ $3 CH_3CHOHCH_2CH_3$ $+8H^+$ $\rightarrow$ $2Cr^{3+}$ $+$ $3CH_3C=OCH_2CH_3$ $+$ $7H_2O$ 3) n_(but-1-ene) = $\frac{1000}{22.4}$ $=$ $44.6\; mol$ m_(butanone) = $2500\cdot 0.81$ $=$ $2025\; g$ n_(butanone) = $\frac{2025}{72}$ $=$ $28.13\; mol $ One mole of but-1-ene would theoretically provide one mole of butan-1-ol, which should provide one mole of butanone. n_{(butanone obtained theoretically)}= $44.6\; mol$ Yield = $\frac{28.13\cdot 100}{44.6}$ $=$ $63.1 \%$