Effect of chloromethyl substituent vs methyl substituent on yields of nitration
The following is the abstract of K.M. Zhang "Selective Nitration Of Benzyl Chloride And Its Application In The Synthesis Of Nitrobenzaldehyde"(link). The full pdf is behind paywall.


  The selective nitration of benzyl chloride and its application in the synthesis of 4-nitrobenzaldehyde were studied. Nitration of benzyl chloride with $\ce{HNO3}$ in the presence of $\ce{Nb2O5}$(6% weight percent) at 0-5℃ for 1.5 hours gave mononitro products in 94% yield with 77-80% para selectivty. $\ce{Nb2O5}$ was recovered by filtration and reused in the nitration. The yield of mononitro products and para selectivity were above 90% and 76% respectively for 5 times repeated use of $\ce{Nb2O5}$. Nitration of benzyl chloride with urea nitrate(UN) in $\ce{H2SO4}$ was also studied. The nitration was carried out at 25℃ for 24 hours and gave mononitro products in 98% yield with 90% para selectivity. Base catalyzed hydrolysis of 4-nitrobenzyl chloride at 75-80℃ for 22 hours gave 4-nitrobenzyl alcohol in 77% yield with 98% purity. Oxidation of 4-nitrobenzyl alcohol in dilute nitric acid at 55℃ for 3 hours gave 86% 4-nitrobenzaldehyde, compared with industrial oxidation of 4-nitrobenzyl alcohol,whichwas carried out at 70℃for 4 hours and gave 70% 4-nitrobenzaldehyde. 4-nitrobenzaldehyde was also obtained in 86% yield with 92% purity via ionic liquid immobilized $\ce{TEMPO/CuCl}$ catalyzed oxidation of 4-nitrobenzyl alcohol with molecular oxygen in ionic liquid $\ce{[bmim]PF6}$. The reaction condition is mild, the selectivity is high, and no 4-nitrobenzoic acid is detected in any case.