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ALDEHYDES AND KETONES

RESULTS

Table 1. General Test for Carbonyl Compounds (Aldehydes and Ketones)!u"leoph#l#" Add#t#on of $%&'!*

CarbonylCompound

es"r#pt#on of rodu"t

(henylhydra+one)

Test

Response(,-')

Chem

Rn

Formaldehyde

Benzaldehyde

Acetone

Chemical Equation!

"a

"#

"c

Table $. General Test for Aldehydes /#dat#on by Tollen0s Reaent

$eneral Equation!

Carbonyl

Compound

es"r#pt#on of Result#n 2#ture

Test

Response

(,-')

Che

m

Rn

Formaldehyde A% mirror &a 'ormed( Clear olution ) *a

)

) H*O

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Benzaldehyde Formation o' emulion( Dirty &hite olution + *#

Acetone No A% mirror 'ormed( Clear olution ) *c

Chemical Equation!

*a

*#

NO ,EACT-ON

*c

Ta#le ./ $eneral Tet 'or Ali0hatic Aldehyde! O1idation #y Fehlin%2 ,ea%ent

$eneral Equation!

Carbonyl

Compound

es"r#pt#on of Result#n 2#ture

Test

Response

(,-')

Chem

Rn

Formaldehyde Blue olution 3 Bric4 red 0reci0itate &a

'ormed

) .a

Benzaldehyde Li%hter #lue 3 No 0reci0itate 'ormed + .#

Acetone Dar4 #lue olution 3 No 0reci0itate 'ormed + .c

Chemical Equation!

.a

No reaction

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.# *C5H5CHO ) NaOH 3 C5H5CH*OH )C5H5COONa

.c

Ta#le 6/ 7reer8ati8e Action o' Formaldehyde

rote#n

Sample

es"r#pt#on of Sample es"r#pt#on of Sample

#n *ot 3ater

Solub#l

#ty #n

*$/

(,-')

9ntreated%elatin heet

Did not diol8e in &ater)

$elatin heet

treated &ith

H*C:O

Diol8ed in &ater

+

Ta#le ;/ O1idation #y K

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;# CH.COCH.) K

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containin% mL o' ; ethanol and a dro0 o' each tet com0ound &a added toeach o' &hich it i ai%ned/ The tet tu#e &ith

Second &a the Tollen2 tet &hich i the %eneral tet 'or Aldehyde/Aldehyde are 8ery eaily o1idized to yield car#o1ylic acid or their alt i' the reactioni done in #aic media/ Since 4etone are not readily o1idized> thi tet i a ue'ul

method o' di@erentiatin% #et&een aldehyde and 4etone/ The olution ued in thitet &a an ammoniacal il8er hydro1ide olution &hich i a 8ery mild o1idizin% a%ent/=hen the reaction i 0oiti8e> a il8er mirror ometime i 'ormed on the tet tu#e&hich i reulted 'rom the reduction o' the il8er ion to metallic il8er/ Ordinary4etone do not %i8e a 0oiti8e reult in thi tet/ A%ain> there &ere three tet tu#e0re0ared> each 'or the di@erent tet com0ound/ Each tet tu#e &a occu0ied &ith"mL o' Tollen2 olution/ A dro0 o' each tet com0ound &ere added to each ai%nedtet tu#e/ The tet tu#e &ith 'ormaldehyde and Tollen2olution reacted 0oiti8ely and'ormed a il8er mirror> &hile the tet tu#e &ith #ezaldehyde and acetone didn2t react0oiti8ely/ There &a an emulion 'ormed in the tet tu#e &ith #enzaldehyde &hilethe tet tu#e &ith acetone didn2t ho& any reaction at all/

Third &a the %eneral tet 'or Ali0hatic Aldehyde or the Fehlin%2 tet/ There&ere t&o olution ued 'or thi tet( the Fehlin%2 A> &hich &a a #lue aqueouolution o' co00er-- ul'ate> and the Fehlin%2 B> &hich &a a clear and colorleolution o' aqueou 0otaium odium tartate and a tron% al4ali/ The 'ormation o'#ric4+red 0reci0itate o' cu0rou o1ide indicate the 0oiti8ity and indicate that thecom0ound i an aldehyde/ There &ere three tet tu#e 0re0ared> each 'or eachai%ned tet com0ound/ Each tet tu#e contain a hal' mL o' the Fehlin%2 A olutionand another hal' o' the Fehlin%2 B/ A dro0 o' each olution &a added to each tettu#e/ Then each &a &armed in a &ater #ath/ Only the tet tu#e &ith the tetcom0ound 'ormaldehyde reacted 0oiti8ely> &ith a colored #lue olution and #ric4+red0reci0itate/ The t&o other tet tu#e &ith #enzaldehyde and acetone> re0ecti8ely>&ere alo #lue in color #ut didn2t 0roduce any 0reci0itate/

Ne1t &a the o1idation #y K 7otaium 0erman%anate i a tron%o1idizin% a%ent ued to tet the 0reence o' an aldehyde or a 4etone/ -' thecom0ound 0reent i an aldehyde> it &ill #e readily o1idized #y the 0otaium0erman%anate into a car#o1ylic acid due to the 0reence o' the hydro%enatom #onded to the car#onyl %rou0/ -' the com0ound 0reent i a 4etone> it i%enerally not o1idized #y 0otaium 0erman%anate> unle in e1tremecondition uch a the 0reence o' heat/ -' K a clea8a%e mi1ture o' t&o car#o1ylic acid &ould #e 0reent in theolution/ The reult &hen ; dro0 o' /*< K #enzaldehyde and cyclohe1anone &ould 0oiti8e reult> incethey &ould #e o1idized #y 0otaium 0erman%anate to 'orm #ro&nman%anee dio1ide/ On the other hand> acetone i not e10ected to 0roduce a0oiti8e reult 'or 0otaium 0erman%anate/

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The tet 'or methyl 4etone %rou0 or the -odo'orm tet &a the lat tet0er'ormed/ acetaldehyde CH.CHO &ill alo 'orm iodo'orm under the ame condition/Alcohol o' the ty0e decri#ed are eaily o1idized to methyl 4etone under thecondition o' the iodo'orm reaction/ T&o tet tu#e &ere 0re0ared and occu0ied &ith

a olution o' 'ormaldehyde and acetone ; dro0 o' each com0ound &ith * mL &ater/Fi8e dro0 o' -*olution and a 'e& dro0 o' NaOH &ere added until the #ro&n olution&a dichar%ed/ -t &a then &armed in &ater #ath/ A'ter the &ater #ath> the'ormaldehyde olution &ith -* and a 'e& dro0 o' NaOH &a till #ro&n in color and0roduced ome &hite 0reci0itate/ Ho&e8er> the acetone olution chan%ed it olutioncolor 'rom #ro&n to &hite and li4e the 'ormaldehyde olution> the acetone olution0roduced ome &hite 0reci0itate/

,e'erence!

"/ http://www.chemguide.co.uk/organicprops/carbonys/o!idation.htm*/ htt0!&&&/&i4i0remed/com.Ior%anicmechanim/0h0J

mchIcode:.*I../ htt0!&&&/chem%uide/co/u4or%anic0ro0car#onyladdelim/html6/ htt0!en/&i4i0edia/or%&i4iFehlin%Iolution

Abstra"t

A qualitati8e analyi o' aldehyde and 4etone &a conducted in thee10eriment/ Four tet am0le> namely acetone> 'ormaldehyde and#enzaldehyde &ere ued in the e10eriment/ Mariou 0arameter re%ardin% the0hyical 0ro0ertie o' aldehyde and 4etone &ere determined uin% tetuch a the o1idation &ith 0otaium 0erman%anate> *>6+

dinitro0henylhydrazine tet> Tollen2 tet> Fehlin%2 tet> iodo'orm tet andaction o' 'ormaldehyde on 0rotein u#tance/ The o#?ecti8e o' thee10eriment &ere met ince the 0hyical 0ro0ertie o' the aldehyde and4etone &ere o#er8ed uin% the tet/ Ho&e8er> ome e10erimental reultde8iated 'rom the theoretical one> uch a the non+o1idation o' 'ormaldehyde&ith 0otaium 0erman%anate/ Thee un'oreeen error and de8iation in thereult o' the e10eriment can #e attri#uted to the im0uritie that may ha8ealtered the ori%inal reult/ The e10eriment &ould #e 8ery hel0'ul ineta#lihin% the identity o' a certain un4no&n com0ound/

Concluion

The o#?ecti8e o' the e10eriment &ere met a'ter the e10eriment/ Thi idue to the 'act that the 0hyical 0ro0ertie o' aldehyde and 4etone &ereo#er8ed uin% the 'our tet am0le/ Ho&e8er> ome une10ected reult&ere recorded> uch a the non+o1idation o' 'ormaldehyde in 0otaium0erman%anate and the ne%ati8e reult o' acetone and 'ormaldehyde/

The de8iation o' the e10erimental reult 'rom the theoretical one may #eattri#uted to the im0uritie 0reent in ome o' the am0le/ Thee im0uritie
http://www.chemguide.co.uk/organicprops/carbonyls/oxidation.htmlhttp://www.wikipremed.com/03_organicmechanisms.php?mch_code=030208_030http://www.wikipremed.com/03_organicmechanisms.php?mch_code=030208_030http://www.chemguide.co.uk/organicprops/carbonyls/addelim.htmlhttp://en.wikipedia.org/wiki/Fehling's_solutionhttp://www.wikipremed.com/03_organicmechanisms.php?mch_code=030208_030http://www.wikipremed.com/03_organicmechanisms.php?mch_code=030208_030http://www.chemguide.co.uk/organicprops/carbonyls/addelim.htmlhttp://en.wikipedia.org/wiki/Fehling's_solutionhttp://www.chemguide.co.uk/organicprops/carbonyls/oxidation.html

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0reent may ha8e hindered any reaction> or 0roduced a ne& reaction &hichmay #e the reaon &hy the reult de8iated 'rom the e10ected one/

-n order to a8oid the con'uion in determinin% &hether the com0ound i analdehyde or a 4etone> it i recommended to conduct additional tet that&ould #etter eta#lih the identity o' a certain com0ound

7rocedureA/a/ $eneral Tet 'or Car#onyl Com0ound"/ " dro0 o' the tet com0ound &a added in a tet tu#e containin% mL o'; ethanol/*/ mL o' *>6+DN7H &a added ne1t/./ Sha4ed and tand 'or 'e& minute/#/ Tollen2 Tet"/ " mL o' Tollen2 olution &a tran'erred in a clean tet tu#e/*/ " dro0 o' tet com0ound &a then added/

./

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