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Selective Nitration Of Benzyl Chloride And Its Application In The Synthesis Of Nitrobenzaldehyde

Posted on:2008-12-25Degree:MasterType:Thesis
Country:ChinaCandidate:K M ZhangFull Text:PDF
GTID:2191360215498386Subject:Applied Chemistry
Abstract/Summary:PDF Full Text Request
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.
Keywords/Search Tags:benzyl chloride, nitration, hydrolysis, oxidation, 4-nitrobenzaldehyde
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