Organic Chemistry Laboratory Formal Report CHEMISTR
#nthesis o" ()nitrobenzaldeh#de using nitration reaction to benzaldeh#de
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Dave Gabriel E. Cadungog*, Ronald Roie Bernadas, Chesler Ramirez, Patrick Malcolm antos De!artment o" Chemistr#, College o" cience
*Corresponding *Corresponding author; e-mail:
[email protected] [email protected]
$bstract %n this e&!eriment, the researchers 'anted to s#nthesize () nitrobenzaldeh#de. .+ mol conc. - /0 and .01 mol -2/ ( 'as used to !roduce the nitronium ion 'hich is the electro!hile. 3his e&!eriment used an aroma aromatic tic subst substitu itutio tion n reac reactio tion n using using an elec electro tro!hi !hile, le, !arti !articu cular larl# l# nitr nitra ation tion !roc !roces ess. s. 3he 3he s#nt s#nthe hesi sis s reac reacti tion on !rod !roduc uced ed (.4 (.4 g () nitrobenzaldeh#de 'ith a !ercent #ield o" 0.45.
Keywords: Electrophilic addition, Nitration, Synthesis, Aromatic compound
%ntroduction
A lot of derivatives derivatives of benzene were originally isolated from the fragrant balsams balsams obtained from trees and plants. These compounds were described as aromatic due to its pleasant odors. However, it was discovered that many derivatives of benzene are odorless odorless.. Yet, et, they are still still called called aromati aromatic c to describ describe e all derivat derivatives ives of benzen benzene e regardless of their fragrance (Solomons, et al., !"#$ %lectr %lectrop ophil hilic ic aroma aromatic tic subst substitu itutio tion n react reaction ion is a reacti reaction on where where one one of the the aromatic protons is replaced by an electrophile where the aromatic moiety is preserved. %&le %&les s of this are bromina bromination tion,, chlorina chlorination tion,, nitratio nitration, n, sulfonat sulfonation' ion'des desulfo ulfonati nation, on, 1
Organic Chemistry Laboratory Formal Report riedel) riedel)*raf *rafts ts al+ylati al+ylation on and acylatio acylation, n, reducti reduction, on, benzyl benzylic ic formatio formation, n, o&idati o&idation, on, and *lemmensen reduction (lein, !"$. -itration happens when benzene is treated with a mi&ture of nitric acid and sulfuric acid which results to formation of nitrobenzene. t can also be done by using H-/0 alone, or a mi&ture with organic acids li+e sulfuric acid, selenic acid, or acetic anhydrid anhydride e (-orman (-orman and Taylor, ylor, "123$. "123$. This This reaction reaction proceed proceeds s via an electrop electrophili hilic c aromatic substitution substitution where nitronium ion is formed and believed to be the electrophile. electrophile. This This elect electrop rophi hile le forms forms when when the acid) acid)ba base se reacti reaction on betwe between en H-/ H-/ 0 and H S/# happens. The nitric acid in this situation, must be completely ionized into the nitronium ion. The figure " below represents the nitration reaction to produce a nitrobenze using the reagents needed.
Figure 1
n this this e&per e&perime iment, nt, the the ob4ect ob4ective ive is to synth synthes esize ize a compo compoun und d which which is 0) nitrobenzaldehyde. t was done by doing the said type of reaction above. igure shows the structure of the said compound. t can be seen that the compound contains an aldehyde, phenyl group and a nitronium ion.
2
Organic Chemistry Laboratory Formal Report Figure 2
E&!erimental methodolog#
A #3 m5 of concentrated concentrated H S/# was filled on a 3! m5 flas+. #3 m5 of fuming H-/ 0 was carefully added while stirring and cooling with an ice bath. Temperature of the mi&ture did did not not e&cee e&ceed d "! /*. 3.0 3.0 g of benz benzal alde dehy hyde de was was adde added d in the the mi&t mi&tur ure e and and the the temperature was +ept constant at "3 /* for about " hour. ce bath was removed and the reaction mi&ture was stored overnight in room temperature. /n a 3!! m5 bea+er, the reaction mi&ture was poured with 3! g crushed ice. The yellow precipitate formed was suc+ed off over a 6uchner funnel and washed with "!! m5 cold water. t was then dissolved in 23 m5 diethyl ether and then sha+en out with 23 m5 of 37 -aH*/
0
solution. The organic phase was dried over sodium sulfate, filtered and solvent was sub4ected to rotary evaporator. Amount of 0)nitrobenzaldehyde produced was measured and percent yield was calculated. Results and discussion
n the e&periment, the mi&ture of the concentrated sulfuric acid and nitric acid is necessary to produce the nitronium ion which will react with the benzene resulting to a nitrobenzene. nstead of using pure benzene, benzaldehyde was used instead to get the wanted compound. The reaction mi&ture used crushed ice for the resulting product to precipitate and be collected. Since the compound being synthesized is insoluble to water, water was 3
Organic Chemistry Laboratory Formal Report used to collect it. Then, the crude was dissolved in diethyl ether and 37 -aH*/ 0 was added. The addition of 37 -aH*/ 0 was done so the e&cess acids in the reaction which were not used will be dissolved by it. t might affect the yield of synthesis if the e&cess acids will not be removed. The organic phase then was dried over sodium sulfate. n this e&periment, instead of using sodium sulfate, magnesium sulfate was used instead. This procedure will remove e&cess water in the product. The table below shows the result of the e&periment. t can be seen that the synthesis synthesis of 0)nitrobenzaldehyde 0)nitrobenzaldehyde produced only 0.!23g. 0.!23g. The theoretical theoretical yield which is 8.33g was calculated using stoichiometry and the values or amount of reactants used resulting to the production of the said compound. Mass o" Beaker Mass o" Beaker 'ith am!le 3heoretical 6ield E&!erimental 6ield Percent 6ield The overall reaction has
23.11 2.0#! 8.33 g 0.!23 #!.27 a percent yield of #!.27. t was calculated using the
theoretical and e&perimental yield value using the e9uation
Experimental Experimental Yield × 100 . Theoretical Yield
A total total of 0.!23 g 0)nitrobenzaldehyde 0)nitrobenzaldehyde was synthesized synthesized in this e&periment. e&periment. This leads to a #!.27 yield of the desired compound. /ne of the things that may affect the yiel yield d is the the prep prepar arat atio ion n of the the nitr nitrat atio ion n mi&t mi&tur ure. e. The The temp temper erat atur ure e migh mightt not not be maintained below "! /*. Re"erences
ryhle, *.: Snyder, S.: Solomons, ;. Organic Chemistry 11th Edition. Sons Singapore ?te. 5td.@ Asia. !"#: p.28# lein, . Organic Chemistry 2 nd Edition. Sons, nc.@ BSA. !": pp. CC) CC# -orman, D.: Taylor, D. Electrophilic Sustitution in !en"enoid Compounds# %lsevier ?ublishing *ompany@ -etherlands, "123: p. 2", 2# 4
