Dissertation > Industrial Technology > Chemical Industry > Basic Organic Chemistry Industry > The production of aromatic compounds > Aromatic aldehydes,aromatic ketones and their derivatives,quinones and their derivatives > Aromatic aldehydes and their derivatives

Selective nitration of benzyl chloride and its application nitrobenzaldehyde synthesis

Author ZhangKaiMing
Tutor WeiYunYang
School Nanjing University of Technology and Engineering
Course Applied Chemistry
Keywords benzyl chloride nitration hydrolysis oxidation 4-nitrobenzaldehyde
CLC TQ244.1
Type Master's thesis
Year 2007
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The selective nitration of benzyl chloride and its application in the synthesis of4-nitrobenzaldehyde were studied. Nitration of benzyl chloride with HNO3 in the presenceof Nb2O5(6% weight percent) at 0~5℃for 1.5 hours gave mononitro products in 94%yield with 77~80% para selectivty. Nb2O5 was recovered by filtration and reused in thenitration. The yield of mononitro products and para selectivty were above 90% and76%,respectively for 5 times repeated use of Nb2O5.Nitration of benzyl chloride with urea nitrate(UN) in H2SO4 was also studied. Thenitration was carried out at 25℃for 24 hours and gave mononitro products in 98% yieldwith 90% para selectivty.Base catalyzed hydrolysis of 4-nitrobenzyl chloride at 75~80℃for 22 hours gave4-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 liquidimmobilized TEMPO/CuCl catalyzed oxidation of 4-nitrobenzyl alcohol with molecularoxygen in ionic liquid [bmim]PF6. The reaction condition is mild、the selectivity is high,and no 4-nitrobenzoic acid is detected in any case.

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