Spec Prob Set 315 Current (1)

CHEMISTRY 315

IR, MS, UV SPECTROSCOPY PROBLEM SET

All Sections

CHEMISTRY 315 IR, MS, UV SPECTROSCOPY PROBLEM SET Consult the Lab Manual, the textboos b! Solo"ons an# b! Pa$%a, et al &, &, an# the 'ollo(%n) #%s*uss%on to hel+ !ou (%th the anal!ses& In the Lab Manual se*t%on, S+e*tos*o+! I, thee %s a se*t%on t%tle# -Us%n) On.l%ne /atabases to Hel+ Sol$e O)an%* Che"%st! S+e*tos*o+! Poble"s-& You You shoul# e$%e( %t so !ou *an use on.l%ne sou*es to hel+ !ou anal!0e so"e o' the +oble" s+e*ta an# as a sou*e 'o l%teatue s+e*ta& The MU O)an%* Che"%st! (eb +a)e 2htt+44"ason&)"u&e#u4ssla!#en4Lab4%n#ex&ht"l htt+44"ason&)"u&e#u4ssla!#en4Lab4%n#ex&ht"l66 has l%ns to the #atabases& You You eall! (%ll '%n# th%s "ate%al eas%e to "aste %' !ou tae the lo)%*al a++oa*h outl%ne# %n the "anual an# %n Pa$%a& I' !ou ae un'a"%l%a (%th a *o"+oun#7s na"e, loo %t u+ on.l%ne, o %n the textboo, Me*, CRC, o 8l#%*h *atalo)& The Lab Manual has a l%st o' e'een*e sou*es %n the se*t%on -9%n#%n) an# C%t%n) In'o"at%on 'o the Laboato!-& Part I 8ns(e the :uest%ons %n the s+a*e +o$%#e# on the +a)e&

1& a6 9o ea*h o' the *o"+oun#s belo(, '%st (%te a strctral !or"la  an# then %n#%*ate (h%*h o' the" %s l%el! to absob %n the UV e)%on& B%e'l! ex+la%n !ou eason%n)& 8& *!*lohexanol

C#H1$O

B& ;,<.hexa#%enal

C#H%O

C& ;."eth!l.5.$%n!l+!%#%ne

C%H&'

C!*lohexanol %s l%el! to absob UV& The eason %s that %t has an OH )ou+ on %t that ha$e ; unshae# +a%s o' ele*tons that absob the UV& UV&  b6 8n unno(n ox!)en.*onta%n%n) *o"+oun# %s sus+e*te# o' be%n) an al*ohol, a etone, o a *abox!l%* a*%#& Its IR s+e*tu" sho(s both a boa# ston) +ea at 31==.3<== *".1 an# a sha+ ston) +ea at 1>== *".1& ?hat %n# o' *o"+oun# %s %t@ Ex+la%n (hat !ou (oul# see %n the s+e*ta o' the t(o *o"+oun#s that !ou #%# not *hoose that allo(s !ou to #%''eent%ate these thee *lasses o' *o"+oun#s& The *o"+oun# %s a *abox!l%* a*%# as the boa# ston) +ea at 31==.3<== *".1 *oes+on#s to CAO bon# an# the sha+ ston) +ea at 1>== *".1 *oes+on#s to O.H bon#& 9o al*ohol, a ston) boa# +ea (%ll be obse$e# bet(een 3;==.3== *".1& 9o etone, a ston) "e#%u" +ea (%ll be obse$e# aoun# 1>;5 *".1&

*6 S+e*%'%* *o"+oun#s ae na"e# %n the boxes belo( an# the 'un*t%onal )ou+ +at o' the na"e %s %n bol#'a*e& 9o ea*h bol#'a*e 'un*t%onal )ou+, #a( an ex+an#e# stu*tual 'o"ula& In#%*ate the a++ox%"ate (a$enu"bes o' the IR abso+t%on +eas that *oul# be use# to #%st%n)u%sh bet(een the "e"bes o' ea*h o' the +a%s o' *o"+oun#s %n a o(& Ment%on at least one #%st%n)u%sh%n) abso+t%on +ea 'o eac( *o"+oun# %n the +a% that %s absent %n the s+e*tu" o' the othe *o"+oun# 2ex*e+t 'o the *o"+oun# %n the lo(e %)ht box6& Exa"+le a*etonitrile  an# "eth!la"ine CD

H; 2+%"a! a"%ne6

 %t%les ha$e a C t%+le bon# stet*h at ;;5= *".1F sha+ P%"a! a"%nes ha$e an H stet*h aoun# 35==.33== *".1 that a++eas as t(o ban#s 2the C s%n)le bon# stet*h at 135=.1=== *".1 %s (ea an# #%''%*ult to #%st%n)u%sh6&

8&

B&

C&

1.+o+anol

"eth!l eth!l et(er

.OH 8l*ohols ha$e a OH s%n)le bon# stet*h at 3;==.3== *".1F ston)  boa#

.CO Ethes ha$e a CO s%n)le bon# stet*h at 1===.133= *".1F ston) "e#%u"

1.+ent)ne

1,3.+enta#%ene

CDC 8l!nes ha$e a t%+le bon# stet*h at ;1==.;;== *".1F sha+

CAC 8lenes ha$e a #ouble bon# stet*h at 1== . 1G= *".1F sha+

+entanal

;.+entanone

.CHO 8l#eh!#es ha$e a CAO bon# stet*h at 1>1=.1>5= *".1F ston) The! also ha$e a C.H bon# stet*h at ;G;=.;G5=  ;>;=.;>5= *".1F "e#%u", t(o +eas

.CAO etones ha$e a CAO bon# stet*h at 1>1=. 1>;5 *".1F "e#%u" to sha+

;& Sho(n on the next +a)e ae the IR s+e*ta o' the 'ou %so"e%* but!l *hlo%#es& The s+e*ta ae *leal! #%''eent, as ae the% stu*tues& *ocs on t+o o! t(e asor-tion re.ions in t(e s-ectra/ 013% c" 21 an 05$5 c"21& ot%*e the $a%ab%l%t! %n %ntens%t! an# a++eaan*e o' the  +eas %n those t(o e)%ons 'o the %so"es& Ma these e)%ons on the s+e*ta on the next +a)e& a6 9o the t(o IR s+e*ta belo(, s+e*%'! %n the (h%te s+a*e on the s+e*ta, (hethe the! *onta%n an n.but!l, sec.but!l, %sobut!l, o tert .but!l )ou+& C%*le the +eas that Just%'! !ou *ho%*es us%n) the s+e*ta on the next +a)e 'o *o"+a%son& Re"e"be to *o"+ae the t(o %"+otant abso+t%on e)%ons s+e*%'%e# abo$e&  b6 ?h%*h o' these t(o s+e*ta %s o' an ao"at%* *o"+oun#@ Ma the +eas that Just%'! !ou *ho%*e& Pt all )or ans+ers on t(is -a.e &

8t 13G5 *".1, the abo$e IR s+e*tu" *onta%ns t(o +eas s+l%t %n the sa"e 'ash%on as o' t.but!l *hlo%#e& 8t 5;5 *".1, a sha+ ston) +ea ex%sts 'o both s+e*ta 2abo$e an# t.but!l *hlo%#e6& Thus, the abo$e "ole*ule *onta%ns t.but!l *hlo%#e& Th%s %s an ao"at%* *o"+oun# as %t *onta%ns "ult%+le "e#%u" (ea stet*h ban#s at 1<==. 1== *".1 (h%*h *oes+on# to the CAC bon#&

8t 13G5 *".1, the abo$e IR s+e*tu" *onta%ns a sha+ +ea o' the sa"e 'ash%on as o' n.but!l *hlo%#e& 8t 5;5 *".1, the absen*e o' a sha+ ston) +ea 'o both s+e*ta 2abo$e an# n.but!l *hlo%#e6 %n#%*ates that the abo$e "ole*ule *onta%ns n.but!l *hlo%#e&

3& o to the IST (eb s%te 2htt+44(ebboo&n%st&)o$4*he"%st!46 an# '%n# the "ass s+e*tu" 'o ;.bo"obutane& To +%nt the "ass s+e*tu", s*oll #o(n an# *l%* on KV%e( %"a)e o' #%)%t%0e# s+e*tu" 2*an  be +%nte# %n lan#s*a+e o%entat%on6& Chan)e the +a)e o%entat%on to K Landscape %n the *ile 4 Print4 Pro-erties  (%n#o(& I' !ou )et an eo "essa)e, eloa# the +a)e an# t! to +%nt a)a%n& Cal*ulate the "ole*ula (e%)ht o' ;.bo"obutane to )u%#e !ou (hee to loo 'o the h%)hest "ass +eas& Re"e"be, the "ass s+e*tu" %tsel' (%ll sho( onl! the %nte)al "ass, not the "ole*ula (e%)ht, (h%*h %s an a$ea)e o' all the ato"%* %soto+es +esent %n the sa"+le& Be'oe !ou lea$e the (ebs%te, "ae sue !ou (%te on the +%nte# *o+! the "ass nu"bes o' the +eas o' h%)hest M40 2the! "a! be $e! s"all6 an# se$eal othe +eas& It %s eas%e to see the" on the "on%to s*een than on a bla* an# (h%te +%ntout&

a6 On the printed spectrum o' ;.bo"obutane, %n#%*ate the t+o isoto-ic "oleclar ion -ea6s an# the% M40 at%os 2e'e ba* to the #%s*uss%on %n the lab "anual on MS6&  b6 On the printed spectrum o' ;.bo"obutane, %n#%*ate the M40 'o the +ea o' )eatest %ntens%t!& ?hat 'a)"entat%on o' the ;.bo"obutane a**ounts 'o %ts +esen*e@ /a( the stu*tue o' the *ha)e# 'a)"ent& 8tta*h the +%ntouts to !ou othe ans(es 'o" Pat I&

Part II Ea*h Co"b%ne# S+e*ta Poble" on the 'ollo(%n) +a)es *onta%ns so"e *o"b%nat%on o' th%s %n'o"at%on IR s+e*tu", "ass s+e*tu" o "ole*ula %on +ea, "aJo UV +ea, ele"ent  "ass& On ea*h s+e*tu", neatl! label the "aJo abso+t%on +eas (%th the stu*tual 'a)"ent that *auses the abso+t%on& On the ans(e sheet that 'ollo(s ea*h +oble", '%ll %n the e:ueste# %n'o"at%on so that !ou asse"ble all the stu*tual %n'o"at%on that *an be obta%ne# 'o" the s+e*ta& Then, us%n) th%s %n'o"at%on, +o+ose the stu*tue an# %#ent%t! o' the *o"+oun#& 8 lo)%*al anal!s%s o' the #ata to su++ot the %#ent%'%*at%on shoul# be (%tten %n the -Co"b%ne# 8nal!s%s- se*t%on& You *an *on'%" the %#ent%t! 'o" l%teatue o on.l%ne sou*es& 8 *o"+lete# exa"+le %s )%$en&

E7a"-le S-ectra Prole"   The s+e*ta hee ha$e been "ae# to %n#%*ate "aJo abso+t%ons& Othe ans(es ae entee# on the next +a)e&

8ns(e to Exa"+le Poble" Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s GG& Be*ause th%s %s an e$en nu"be, the *o"+oun# has e%the no n%to)en ato"s o an e$en nu"be o'  ato"s& The h%)hest "40 +eas #o not sho( e$%#en*e o' the +esen*e o' ato"s su*h as Cl o B 2(h%*h (oul# ha$e t(o +eas %n >5;5 an# 5=5= at%os, es+e*t%$el!6&

Ele"ental 8nal!s%s  one (as )%$en&

UV.$%s%ble 8nal!s%s  o %n'o"at%on (as )%$en& IR 8nal!s%s The abso+t%on at 3=== *" 1 2an# not to the le't6 sho(s onl! al%+hat%* 2satuate#6 CH )ou+s& The *abon!l, CAO, absobs ston)l! at 1><= *" 1& The t(o %ntense +eas bet(een 1===.13== *" 1 %n#%*ate the *abon!l belon)s to the este )ou+& The CAO abso+t%on %s (%th%n the an)e 'o an este )ou+& Co"b%ne# 8nal!s%s The IR sho(s the onl! 'un*t%onal )ou+ +esent %s an este& Thee %s no ao"at%*%t! o othe unsatuat%on %n the "ole*ule 2ex*e+t 'o the CAO6& The este )ou+ a**ounts 'o << a"u o' the GG %nte)al "ass& The e"a%n%n) "ass 2GG.<
Stu*tue

O

C3HGO;

CH3 C

O

CH;CH3

1&

8ns(e to Poble" 1 Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s 1=& Be*ause th%s %s an e$en nu"be, the *o"+oun# has e%the no n%to)en ato"s o an e$en nu"be o'  ato"s& The h%)hest "40 +eas #o not sho( e$%#en*e o' the +esen*e o' ato"s su*h as Cl o B 2(h%*h (oul# ha$e t(o +eas %n >5;5 an# 5=5= at%os, es+e*t%$el!6&

Ele"ental 8nal!s%s  one (as )%$en&

UV.$%s%ble 8nal!s%s  o %n'o"at%on (as )%$en&

IR 8nal!s%s The abso+t%on at 1== an# 1<>5 *" 1 sho(s the +esen*e o' an ao"at%* *o"+oun#& Peas )eate than 3=== *".1 'uthe +o%nt to the ao"at%* *o"+oun#&

Co"b%ne# 8nal!s%s The IR sho(s the "ole*ule %s "ono subst%tute# ao"at%*& Thee %s no othe unsatuat%on %n the "ole*ule& Ben0ene 2CH56 a**ounts 'o >> a"u o' the 1= %nte)al "ass& The e"a%n%n) "ass 21=.>>A ;6 belon)s to one o "oe h!#o*abon )ou+s& S%n*e the h!#o*abon )ou+2s6 "ust be satuate#, thee "ust be ; *abons 2;< a"u6 an# 5 h!#o)ens 25 a"u6 A ; a"u& The "ole*ula 'o"ula %s thus CGH1=& Ente%n) the "ole*ula 'o"ula %nto the sea*h +a)e o' an on.l%ne s+e*tos*o+! #atabase, an# *o"+a%n) the no(n s+e*ta (%th the unno(n7s s+e*ta "at*hes onl! one o' the  +oss%b%l%t%es&

Unno(n I#ent%t! S!non!" Thus, the unno(n %s %#ent%'%e# as eth!l ben0ene eth!l ben0ol

Mole*ula 9o"ula

CGH1=

Stu*tue

;& UV λ"ax ;=5 n", lo) e A ;&;

C <&3F H &>

8ns(e to Poble" ; Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s >3& Be*ause th%s %s an o## nu"be, the *o"+oun# has o## nu"be o'  ato"s& The h%)hest "40 +eas #o not sho( e$%#en*e o' the  +esen*e o' ato"s su*h as Cl o B 2(h%*h (oul# ha$e t(o +eas %n >5;5 an# 5=5= at%os, es+e*t%$el!6&

Ele"ental 8nal!s%s The ele"ental anal!s%s %n#%*ates the +esen*e o' 3 C 2=&<3 Q >3 A 36 ato"s an# > H 2=&=> Q >3 A >6 ato"s& The C3H> )ou+ a**ounts 'o <3 a"u o' the >3 %nte)al "ass& The e"a%n%n) "ass 2>3.<3A 3=6 belon)s to an ato" o a )ou+ o' ato"s&

UV.$%s%ble 8nal!s%s  o *on*ete %n'o"at%on obta%ne#&

IR 8nal!s%s The abso+t%on at 33== *" 1 sho(s the +esen*e o' .H bon#& The a"%#e, CAO, absobs ston)l! at 1>= *" 1& The CAO abso+t%on %s (%th%n the an)e 'o an a"%#e )ou+&

Co"b%ne# 8nal!s%s The IR sho(s the onl! 'un*t%onal )ou+ +esent %s an a"%#e& Thee %s no ao"at%*%t! o othe unsatuat%on %n the "ole*ule 2ex*e+t 'o the CAO6& Th%s %"+l%es that the e"a%n%n) "ass 2>3. <3A 3=6 belon)s to one  an# one O ato"s& The bas%* stu*tue "ust be R.CO.H.R,(hee  both R an# R7 *annot be H& The "ole*ula 'o"ula %s thus C3H>O& Ente%n) the "ole*ula 'o"ula %nto the sea*h +a)e o' an on.l%ne s+e*tos*o+! #atabase, an# *o"+a%n) the no(n s+e*ta (%th the unno(n7s s+e*ta "at*hes onl! one o' the +oss%b%l%t%es&

Unno(n I#ent%t! S!non!" Thus, the unno(n %s %#ent%'%e# as n."eth!l a*eta"%#e Mole*ula 9o"ula

C3H> O

Stu*tue

3& UV λ"ax ;G= n", lo) e A 1&3

8ns(e to Poble" 3 Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s G& Be*ause th%s %s an e$en nu"be, the *o"+oun# has e%the no n%to)en ato"s o an e$en nu"be o'  ato"s& The h%)hest "40 +eas #o not sho( e$%#en*e o' the +esen*e o' ato"s su*h as Cl o B 2(h%*h (oul# ha$e t(o +eas %n >5;5 an# 5=5= at%os, es+e*t%$el!6&

Ele"ental 8nal!s%s  one (as )%$en&

UV.$%s%ble 8nal!s%s The %n'o"at%on sho(s the +esen*e o' a etone&

IR 8nal!s%s The abso+t%on at 3=== *" 1 2an# not to the le't6 sho(s onl! al%+hat%* 2satuate#6 CH )ou+s& The abso+t%on at 1<5 *".1 sho(s the +esen*e o' CH; )ou+& The *abon!l, CAO, absobs ston)l! at 1><= *" 1& The absen*e o' al*ohols, estes an# al#eh!#es %n#%*ates that the *abon!l belon)s to the etone )ou+& The CAO abso+t%on %s (%th%n the an)e 'o a etone )ou+&

Co"b%ne# 8nal!s%s The IR sho(s the onl! 'un*t%onal )ou+ +esent %s a etone& Thee %s no ao"at%*%t! o othe unsatuat%on %n the "ole*ule 2ex*e+t 'o the CAO6& The etone )ou+ a**ounts 'o ;G a"u o' the G %nte)al "ass& The e"a%n%n) "ass 2G.;GA >=6 belon)s to one o "oe h!#o*abon )ou+s& The bas%* stu*tue "ust be *!*l%* "ole*ule bon#e# to the C o' the etone& S%n*e the h!#o*abon )ou+2s6 "ust be satuate#, thee "ust be 5 *abons 2= a"u6 an# 1= h!#o)ens 21= a"u6 A >= a"u& The "ole*ula 'o"ula %s thus CH1=O& Ente%n) the "ole*ula 'o"ula %nto the sea*h +a)e o' an on.l%ne s+e*tos*o+! #atabase, an# *o"+a%n) the no(n s+e*ta (%th the unno(n7s s+e*ta "at*hes onl! one o' the  +oss%b%l%t%es&

Unno(n I#ent%t! S!non!" Thus, the unno(n %s %#ent%'%e# as *!*lohexanone Mole*ula 9o"ula

CH1=O

Stu*tue

<& UV λ"ax ;1> n", lo) e A 3&G

C G<&GF H >&1

8ns(e to Poble" < Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s 1G& Be*ause th%s %s an e$en nu"be, the *o"+oun# has e%the no n%to)en ato"s o an e$en nu"be o'  ato"s& The h%)hest "40 +eas #o not sho( e$%#en*e o' the +esen*e o' ato"s su*h as Cl o B 2(h%*h (oul# ha$e t(o +eas %n >5;5 an# 5=5= at%os, es+e*t%$el!6& The ule o' th%teen +o%nts to a "ole*ula 'o"ula o' C15H1G o C1
UV.$%s%ble 8nal!s%s  oth%n) *on*ete (as obta%ne#&

IR 8nal!s%s The abso+t%on at 15== *" 1 sho(s ao"at%* *o"+oun#& The ao"at%* *o"+oun# %s "ono. subst%tute# be*ause o' a an)e o' +eas bet(een 1==  ;=== *".1& The ethe, C.O, absobs ston)l! at 11== *" 1& The C.O abso+t%on %s (%th%n the an)e 'o an ethe )ou+&

Co"b%ne# 8nal!s%s The IR sho(s the onl! 'un*t%onal )ou+ +esent %s an ethe& Thee %s ao"at%*%t! +esent& The O ato" a**ounts 'o 1 a"u o' the 1G %nte)al "ass& The e"a%n%n) "ass 21G.1A 1 G;6  belon)s to one o "oe ao"at%* )ou+s& The bas%* stu*tue "ust be ROR7& S%n*e the ao"at%* )ou+ %s "ono subst%tute#, thee "ust be > *abons 2G< a"u6 an# > h!#o)ens 2> a"u6 A 1 a"u& Th%s %"+l%es that thee ae t(o "ono.subst%tute# ao"at%* *o"+oun#s (%th ethe as the 'un*t%onal )ou+ bet(een the"& The "ole*ula 'o"ula %s thus C1
Mole*ula 9o"ula

C1
Stu*tue

5& UV λ"ax ;=G n", lo) e A 1&5

C 33&;F H <&

8ns(e to Poble" 5 Mass S+e*tu" 8nal!s%s The %nte)al "ole*ula (e%)ht o' the unno(n %s 1=G& Be*ause th%s %s an e$en nu"be, the *o"+oun# has e%the no n%to)en ato"s o an e$en nu"be o'  ato"s& The h%)hest "40 +eas sho( e$%#en*e o' the +esen*e o' Cl&

Ele"ental 8nal!s%s The ele"ental anal!s%s %n#%*ates the +esen*e o' 3 C ato"s an# 5 H ato"s& 9o" the "ass s+e*tu" anal!s%s, the +esen*e o' Cl %s no(n& The C3H5Cl )ou+ a**ounts 'o > a"u o' the 1=G %nte)al "ass& The e"a%n%n) "ass 21=G.>A 3;6 belon)s to t(o ox!)en ato"s& The "ole*ula 'o"ula %s C3H5O;Cl&

UV.$%s%ble 8nal!s%s The UV.$%s%ble anal!s%s *oes+on#s to the +esen*e o' a *abox!l%* a*%#&

IR 8nal!s%s The $e! boa# abso+t%on at 31== *" 1 sho(s O.H )ou+& The *abon!l, CAO, absobs ston)l! at 1><= *" 1& The t(o %ntense +eas bet(een 1;==.13== *" 1 %n#%*ate the *abon!l  belon)s to the *abox!l%* a*%# )ou+& The CAO abso+t%on %s (%th%n the an)e 'o a *abox!l%* a*%# )ou+&

Co"b%ne# 8nal!s%s The IR sho(s the onl! 'un*t%onal )ou+ +esent %s a *abox!l%* a*%#& Thee %s no ao"at%*%t! o  othe unsatuat%on %n the "ole*ule 2ex*e+t 'o the CAO6& Ente%n) the "ole*ula 'o"ula %nto the sea*h +a)e o' an on.l%ne s+e*tos*o+! #atabase, an# *o"+a%n) the no(n s+e*ta (%th the unno(n7s s+e*ta "at*hes onl! one o' the  +oss%b%l%t%es&

Unno(n I#ent%t! S!non!" Thus, the unno(n %s %#ent%'%e# as 2S6.2.6.;.*hloo+o+%on%* a*%# Mole*ula 9o"ula

C3H5O;Cl

Stu*tue