The benzylidene diacetate can be
hydrolysed to corresponding benzaldehyde with aqueous acid (iii) By Gatterman – Koch reaction
When benzene or its derivative is treated with carbon monoxide
and hydrogen chloride in the presence of anhydrous aluminium
chloride or cuprous chloride, it gives benzaldehyde or substituted
benzaldehyde (ii) By side chain chlorination followed by hydrolysis
Side chain chlorination of toluene gives benzal chloride, which
on hydrolysis gives benzaldehyde This is a commercial method
of manufacture of benzaldehyde