Question

2. Describe the infrared absorption frequencies that would allow you to distinguish between the following pairs of compounds. (10 points)

2. Describe the infrared absorption frequencies that would allow you to distinguish between the following pairs of compounds. (10 POINTS) (a) 2,3-dimethylbut-2-ene and 2,3-dimethylbut--ene (b) cyclohexa-1,3-diene and cyclohexa-1,4-diene pentanal pentan-2-one butanamide pentan-3-one (e) CH3(CH2)5-С-СーH and CH3(CH2)6_C_N (f) CH,CH-CH-一С_OH and CH3-CH-CH,--C-H oct-1-yne octanenitrile butanoic acid 3-hydroxybutanal

Answer 1

Thechemtcal bnd uchich tore that whege the tooenas of the chemica bond oe chemi cally ditfe ent 4h IR acti The Symm ontoute bonds, uoth the samo c hemicat environmentboth the nds TheCCEea double bond in3 dimethy but mme tric and as a Con sequence a) -2.- ene TR nactive The C-c double bond İn2,3-dimetnd but-Lene has a setching feweny in he Yange of 600 1b6o C The c-c double bonds in Cyclohexa-1,3-die diene these fove shows ohe conjugated n nadure and | 010(4 c-C stretching

The C csiouble bond in Cyclohe xo -1,4 diene ore Un conjv gated in nature and hexe-fore sh ous a 6501660 Cm c) to an he Co double bondin Pentanal is due. al dehyde func ttonality an s a hiphea The C-O double bond in Pentan-2-one s due oKelone finctionality and shouos a louos c-o stretching freqveney asrond 1 15 C un cionali J The c-o dovble bond in butana mide s due to a mi de fun conalrty where the Car bant YOUP s in e sonance oh-lH the co stect ching fsequecy s avyound 1600 cm1.1 "the Peaks doe to N-н stretching

the C- ouble bondn pentan 3 one i doe o ketone. fon clion alt and Sshouos Stotchina .treaeney 15 c th iple bond in oct ynge C- tretching freqe ncy asyovn d 9150 The. c-c tiple bond in ectane nitsile. hoo the o double bond i butano ic ac id bond gne es. 1키ら cmTJ.the C-O Single stretching frequerea sat 2800cm 1966 cmam double bond in 3-ndY0%y bu ta na! the C-o is doe o de hyde foncio nals and Shows higher c=o stretching fvec?»ency a a PPaams at2400 cm