Question

List various method of preparation of benzene and also write one chemical reaction for each case

Answer 1

1) Reforming (cyclization and dehydrogentaion) of n-hexane over Pt-catalyst at temperature 400 C and pressure:

CH3CH2CH2CH2CH2CH3 = C6H6 + 4 H2

2) Dehydrodealkylation of toluene (700 C, pressure 30 atm) or over Pt-catalyst (500-600 C, 40-60 atm):

C6H5CH3 + H2 = C6H6 + CH4

Toluene may be produced from n-heptane according to synthesis 1).

3) Trimerization of acetylene over catalyst activated carbon at 400 C:

3 C2H2 = C6H6

4) Reduction of phenylhalogenides:

C6H5Br + NaH = C6H6 + NaBr

5) Decarboxylation of benzoic acid by heating with an alcaline:

C6H5COOH + 2 NaOH = C6H6 + Na2CO3 + H2O