Lab 3 Full

INTRODUCTION

The specific group of atoms bonded in the organic molecule will determine certain [1]  physical and chemical characteristics to the molecule as a whole.[1] These groups are known as

functional group. The parent chain of the organic molecule can affect the characteristics of  functional group. The functional functional group –OH bonded in the organic molecule molecule is called called alcohol. alcohol. In alcohols alcohols the OH group is attached to a tetrahedral carbon atom. If the carbon that is bonded to the OH is  bonded to one carbon and two hydrogens! the alcohol is a primary "1o# alcohol.

If the carbon that is bonded to the OH is bonded to two carbons and one hydrogen! the alcohol is a secondary "$o# alcohol.

 If the carbon that is bonded to the OH is bonded to three carbons! the alcohol is a tertiary "% o# alcohol.[$]

&ll of these alcohols share some characteristics but other characteristics are different owing to their different structures. 'e(eral tests that in(ol(ed a chemical reaction can be carried out in order to distinguish the chemical properties among the three classes of alcohols such as )ucas )ucas and chromi chromicc acid acid test. test. &lcoho &lcohols ls are (ery import important ant commerc commercial ially ly used used nowaday nowadayss as sol(ents! drugs and disinfectants. *ethanol or methyl alcohol "+H%OH#! ethanol or ethyl alcohol "+H%+H$OH# and $propane or ispprophyl alcohol ""+H%#$+HOH# are the most widely used alcohols.[%]

,hen the hydro-yl group –OH is bonded to a benene ring! it will use the phenol as  parent name. In phenols the OH group is directly attached to a carbon number 1 that is part of an aromatic ring.

&lcohols and phenols are similar in some ways but the chemical properties of phenols can be slightly different from the alcohols e(en though they ha(e the same hydro-yl group  bonded in the compounds.[/] Iron "III# chloride test is commonly used to distinguish between alcohol and phenol group because they react differently with the reagent.

AIM

1. To learn characteristic chemical reactions of alcohols and phenols. $. To use these chemical characteristics for identification of an unknown organic compound.

MATERIALS

1. &0ueous phenol $. &cetone " reagent grade# %. 1utanol /. $utanol 2. $*ethyl $3ropanol 4. +hromic acid solution 5. 6io-ane 7. Iron "III# chloride solution

8. I$9I solution 1:. )ucas reagent 11. 'odium hydro-ide! ;aOH solution 1$.
1. eaker   $. Test tube %. +orks /. 6ropper 

PROCEDURE A. Physical Properties of Alcohols and Phenols

1. 1: drops of each sample were dropped into 4 separate test tubes "1::>1% mm# that $. %. /. 2.

labeled 1butanol! $butanol! $methyl$propanol! unknown & and unknown . ?ach sample was diluted by mi-ing with % m) of distilled water. Into a separate test tube! $m) of prepared water solution of phenol was placed. The homogeneousness of the solutions was obser(ed. The pH test was done by dipping a pH paper into each test tube. The (alue of pH was read by comparing the color of pH paper to the chart on the dispenser.

. Che!ical Properties of Alcohols and Phenols.

i.

Iodoform test.

1. 4 test tubes "12:>17 mm# were labeled 1butanol! $butanol! $methyl$propanol! unknown & and unknown . $. 2 drops of each sample were added into their respecti(e test tube. Then! $ m) of water  was added to each test tube. %. If the compound was not soluble! dio-ane was dropped until the solution become homogenous. /. ;e-t! $ m) of ;aOH solution was added into each test tube and mi-ed by tapping the test tube with a finger. 2. The mi-ture was warmed in a 4: ℃  water bath and prepared solution of I $9I test reagent was dropped with shaking into each test tube until the solution becomes brown. 4. 4 * of ;aOH solution was added by using dropper into each test tube until the solutions  become colorless. The test tubes were kept in the warn water bath for 2 minutes. &fter 2 minutes! the test tubes were remo(ed from the water bath! letting them cool. 5. The test tubes were put to one side and the obser(ation on any changes in the solutions was taken when all the other tests are completed. 7. The formation of light yellow precipitate was obser(ed in each test tube whether it  present or absent. ii.

)ucas Test. 1. 4 test tubes "1::>1% mm# were labeled 1butanol! $butanol! $methyl$propanol! unknown & and unknown . 2 drops of each sample were added into their respecti(e test tube. $. 1 m) of )ucas reagent was added into each test tube. The solutions were mi-ed well by stopping each test tube with a cork! tapping the test tube sharply with finger for a few seconds. The cork was remo(ed after mi-ing and the test tubes were allowed to stand for  2 minutes. %. &fter 2 minutes! any cloudiness formed was carefully obser(ed. &fter 1: minutes! if the cloudiness still absent! the test tubes were warmed for 12 minutes in a 4: ℃   water   bath. /. &ny cloudiness was obser(ed again.

iii.

+hromic &cid. 1. 4 test tubes "1::>1% mm# were labeled 1butanol! $butanol! $methyl$propanol! unknown & and unknown . 2 drops of each sample were added into their respecti(e test tube.

$. To each test tube! 1: drops of reagent grade acetone and $ drops of chromic acid were added. The test tube then placed in a 4: ℃  water bath for 2 minutes. %. &ny changes in color of the solutions were obser(ed. i(. Iron "III# +hloride Test. 1. 4 test tubes "1::>1% mm# were labeled 1butanol! $butanol! $methyl$propanol! unknown & and unknown . 2 drops of each sample were added into their respecti(e test tube. $. $ drops of iron "III# chloride were added to each test tube. %. &ny color changes in each solution was obser(ed and taken. (.
DATA AND OSER"ATION i.

Physical Properties of Alcohols and Phenols SAMPLE 1butanol $butanol $methyl$propanol 3henol
SOLUILIT# IN $ATER 'oluble 'oluble 'oluble 'oluble 'oluble

p% "ALUE 2 2 2 / 2


'oluble

2

. Che!ical Properties of Alcohols and Phenols. i. Iodoform Test. SAMPLE 1butanol $butanol $methyl$propanol 3henol
ii.

iii.

)ucas Test. SAMPLE 1butanol $butanol $methyl$propanol 3henol
i(.

OSER"ATION @emain colourless @emain colourless @emain colourless @emain colourless @emain colourless @emain colourless

OSER"ATION ;o reaction ;o reaction Turns cloudy immediately ;o reaction ;o reaction Turns cloudy immediately

OSER"ATION

 Yellow turn to blue-green solution  Yellow turn to blue-green solution  Yellow colour remain unchange  Yellow colour turn to brown  Yellow turn to blue-green solution  Yellow colour remain unchange

Iron "III# +hloride Test.

SAMPLE 1butanol $butanol $methyl$propanol 3henol
OSER"ATION @emain yellow @emain yellow @emain yellow Aellow changes to (iolet @emain yellow


@emain yellow

DISCUSSION A. Physical Properties of Alcohols and Phenols Sol&'ility in (ater

In this e-periment! when 1butanol! $butanol! $methyl$propanol and phenol are diluted by adding distilled water! all these four samples soluble in water. &lcohols and phenol are really highly soluble in water because of the polar hydro-yl groups –OH in the water and alcohols and phenol can associate one another through the hydrogen bonding.[2]

Acidity of alcohols and phenols

In the pH test of all the a0ueous solution! the result showed that all alcohols and phenol are acidic. The pH (alue of phenol is / while the pH (alue is 2 for 1butanol! $butanol and $ methyl$propanol. The pH (alue of phenol is slightly more acidic compared to alcohols. This is  because the benene ring in the phenol stabilied the negati(e charge of the pheno-ide ion through resonance since benene ring is considered as electron donor.[4]

. Che!ical Properties of Alcohols and Phenols. i. Iodoform test.

Iodoform test is used to identify the presence of +H%+H"OH# group in alcohols.[5]In the e-periment! initially all the samples "1butanol! $butanol! $methyl$propanol! phenol! unknown &! unknown # were mi-ed with iodoform reagent followed b y ;aOH solution in 4:⁰+

water bath to colourise the brown colour. Then! the samples were let cool in room temperature for a while before being obser(ed. The result showed that all the samples remain colourless. Howe(er! theoretically $butanol should form a yellow precipitate in iodoform reaction. Thus! it is assumed that there must be an error while doing the e-periment. Bor primary alcohol! 1butanol does not show any reaction with iodine in a0ueous sodium hydro-ide. Only ethanol gi(es the iodoform reaction because it ha(e the part structure +H%+H"OH#. $butanol which is secondary alcohol has +H%+H"OH# group that can be o-idied to form methyl carbonyl compound. This compound in the presence of ;aOH reacts with iodine resulting in the substitution of the hydrogen atoms present on the carbon atom lying adCacent to the carbonyl group. Triiodo methyl carbonyl compound is formed which then reacts with hydro-ide ions to produce carbo-ylic acid and iodoform "+HI%#.[7]

Triiodo methyl carbonyl compound

Iodoform

+arbo-ylic acid

The chemical e0uation for this reaction is D H

O

 F  +H%+H$ E + E+H% F /I$ F 4;aOH G +H%+H$ E + EO ;a  F 2;aI F 2H$O F +HI%"s#

OH $butanol

'odium salt of  carbo-ylic

iodoform "yellow precipitate#

3henol reacts with iodine in a0ueous sodium hydro-ide. The chemical e0uation for this reaction is D

$methyl$propanol which is tertiary alcohol does not ha(e H atom attached to the carbon with the –OH group. Thus it gi(es a negati(e result for iodoform reaction.

ii.

)ucas Test. )ucas test is used to distinguish among primary secondary and tertiary alcohol by

differentiate the rate of reaction of alcohols with )ucas reagent. The )ucas reagent is a solution of inc chloride in concentrated hydrochloric acid [8]. ,hen 2 drops of the samples "1butanol! $butanol! $methyl$propanol! phenol! unknown &! unknown # were mi-ed with 1 m) of )ucas reagent! $methyl$propanol and unknown 

turn cloudy immediately and the rest showed no reaction. &fter 1: minutes! test tubes with no reaction were placed in 4:⁰ + water bath for 12 minutes. &fter 12 minutes! all the samples do not show any changes. Howe(er! theoretically! secondary alcohol which is $butanol should turn cloudy. Thus! it is assumed that there must be an error while doing the e-periment. Bor 1butanol and phenol! both should not show any changes. Brom the obser(ation! $methyl$propanol which is tertiary alcohol reacts rapidly "within 1 minute# with )ucas reagent to form alkyl chloride. The chemical reaction in(ol(ed is substitution where the –OH group of alcohol is replaced by chloride ion from hydrochloric acid! forming alkyl chloride [/]. The cloudiness indicates the formation of alkyl chloride which is insoluble in a0ueous solution. The chemical e0uation for this reaction is "+H%#%+OH "a0# F H+l "a0# F n+l$ "a0# G "+H#%++l "s# F H$O "l# $methyl$propanol

$chloro$methylpropane

&fter 12 minutes in 4:⁰ + water bath! $butanol which is secondary alcohol should reacts with )ucas reagent to form alkyl chloride which appears as cloudy mi-ture. The chemical e0ua tion for  this reaction is D "+H%#$+H$+HOH "a0# F H+l "a0# F n+l$ "a0# G "+H%#$+H$+H+l "s# F H$O "l# $butanol

$chlorobutane

1butanol as primary alcohol and phenol does not show any reaction with )ucas reagent e(en after 12 minutes in 4:⁰ + water bath. +H%"+H$#$+H$OH F H+l "a0# F n+l$ "a0# G ;o reaction 1butanol

F H+l "a0# F n+l$ "a0# G ;o reaction

iii.

+hromic &cid Test. In chromic acid test! these samples were tested to distinguish primary and secondary alcohols

from tertiary alcohols. Bor 1butanol and $butanol! the yellow colour changed into bluegreen solution. The o-idation state of chromium changed from F4 "yellow colour# to F% "pale green colour#. The reaction with chromic acid occurred because these samples are primary and secondary alcohols. The primary alcohols "1butanol# o-idied and forming an aldehyde "butanal# as intermediate and later forming butanoic acid. Bor secondary alcohol "$butanol#! the o-idation reaction occurs and forming a ketone "$butanone#.

H$+rO/ &cetone 1butanol

F

utanal "intermediate#

utanoic acid

+r$"'O/ #% "bluegreen#

H$+rO/ &cetone $butanol

F $butanone

+r$"'O   /#% "bluegreen#

In the test tube that contained $methyl$propanol! the yellow colour remains unchanged  because this sample is a tertiary alcohol. Thus! o-idation reaction did not occur.

H2CrO4 No Reaction Acetone

Bor phenol! the colour of the solution changed from yellow into brown colour solution. 6ue to the structure of phenol that has a ring structure! the o-idation reaction cannot occur to form either carbo-ylic acid or ketone.

H$+rO/ ;o reaction 3henol

i(.

&cetone

Iron "III# +hloride Test. ,hen 1butanol! $butanol and $methyl$propanol are added with iron "III# chloride

solution! the colour of mi-ture remained yellow. This is because there is no reaction takes place in these three different test tubes. Howe(er! the yellow colour in the solution is showing that the  presence of iron "III# ion in the solution. ut! the mi-ture between phenol and iron "III# chloride solution changed from yellow to (iolet colour which pro(ed that there is a reaction occurred. @eaction between phenol and iron "III# solution will produce another organic compound together with hydrochloric acid. The (iolet colour changed indicates the presence of phenol or enol in the mi-ture. The e0uation in(ol(ed in this solution isD

(.


ased on chromic acid test! the result (erified that unknown & was either primary alcohol or  secondary alcohol. The yellow color of the solution changed to bluegreen solution which  produced by chromium "III# sulfate! +r $"'O/#%.
Birst! for iodoform test! all the samples are let to be cool only for a short period of time  before the reaction is being obser(ed. +onse0uently! we cannot obser(e any yellow precipitate that should be formed in $methly$propanol. 'econd! for )ucas test! the samples in the water   bath are not keep warm! thus the cloudiness in the $butanol cannot be obser(ed as it should be. PRECAUTION STEPS

In iodoform test! all the samples must let to be cool for a longer period of time before doing any obser(ation because the formation of yellow precipitate tends to be slow. ;e-t! in )ucas test! the samples in the water bath must keep warm consistently by closing the co(er of the water bath so that the cloudiness that formed can be seen clearly. CONCLUSION

In conclusion! by conducting this e-periment! we managed to determine the physical  properties the chemical reacti(ity of different classes of alcohols and phenols. ,e also manage to identify what is the group that belong to unknown .
Physical Properties of Alcohols and Phenol

The physical properties of alcohols and phenols are soluble in water. This is because! the  polarity of hydro-yl group that attach to both alcohols and phenols with its ability to form hydrogen bonds! enable alcohols and phenols mi- with water. *eanwhile in acidity properties!  phenol has more acidity than the alcohols.

Che!ical Properties of Alcohols and Phenols Pri!ary Alcohols

3rimary alcohols are an alcohol which contains carbon which carries the OH group is only attached to one alkyl group. In Iodoform test! only 1butanol which is primary alcohol gi(es  positi(e result. 3rimary alcohols react with iodine in a0ueous sodium hydro-ide to gi(e the yellow precipitate iodoform. In chromic acid test! primary alcohols o-idied and forming an aldehyde as intermediate and later forming carbo-ylic acid. Howe(er! when tested with )ucas reagent and iron "III# chloride! primary alcohols do not ha(e any changes in its solution.

Secondary Alcohols

'econdary alcohols are alcohol that! its carbon with the OH group attached is Coined directly to two alkyl groups! which may be the same or different. Bor their chemical beha(ior! secondary alcohols undergo reaction with )ucas reagent and an alkyl chloride compound is formed. ,hen mi-ed with chromic acid! secondary alcohol reacts to form a ketone compound with bluegreen color of solution. Howe(er! secondary alcohols do not react when being tested with Iodoform and iron "III# chloride. 'ince unknown  showed similar obser(ations with $  butanol throughout the e-periment! thus it is categoried in secondary alcohol group. Tertiary Alcohols

Tertiary alcohols are alcohol that contain carbon atom holding the OH group is attached directly to three alkyl groups! which may be any combination of same or different. Tertiary alcohols can be identified by using )ucas test. In this test! tertiary alcohols react with )ucas reagent to form an insoluble alkyl chloride indicated by the immediate formation of cloudiness in the solution. Howe(er! tertiary alcohol do not react Iodoform solution! chromic acid and iron "III# chloride.

Phenol

3henols are any compound with a hydro-yl group linked directly to a benene ring. To identify phenol! iron "III# chloride test is used. ,hen iron "III# chloride solution is added to  phenol! it gi(es a (ioletcolored solution indicating that a reaction had occurred. The (iolet colour changed indicates the presence of phenol or enol in the mi-ture. *eanwhile! phenols gi(e negati(e result to Iodoform! )ucas and chromic acid test.

RE)ERENCES

1. httpDchemwiki.ucda(is.eduOrganicJ+hemistry&lcohols $. httpDchemwiki.ucda(is.eduOrganicJ+hemistry&lcohols %. ailey 3.' K ailey +.& "$:::#! &lcohols! 3henols and ?thers! Organic +hemistry! BrenticeHall! Inc! 'i-th ?dition! pp. $21$75. /. httpDchemwiki.ucda(is.eduOrganicJ+hemistry&lcohols 2. ailey 3.' K ailey +.& "$:::#! &lcohols! 3henols and ?thers! Organic +hemistry! BrenticeHall! Inc! 'i-th ?dition! pp. $21$75. 4. httpDwww.chemguide.co.ukorganicpropsphenolacidity.html 5. httpDchemwiki.ucda(is.eduOrganicJ+hemistry&lcohols@eacti(ityJofJ&lcoholsTheJ  Triiodometha 7. httpDsciencehelp.blog.com$:1%:1$7iodoformtest 8. httpDemployees.oneonta.eduknauerbrchem$$4$$4e-pts$$4Je-pt:7Jpro.pdf 

LA REPORT *ENERAL C%EMISTR# SPL +++,-SAP +++, Eperi!ent , / Identification of Alcohols and Phenols

)ecturerLs nameD &sst. 3rof. 6r. 'ahena Berdosh 6ateD 11th October $:12

 ;o

=roup members

*atric number  

. 1

;oor &mni inti *ohamed

121115:

$

*uhammad &imi in 'haharudin

121%/72

%

*ardhiyana ;aCwa inti Hamdan

12121$$

/

*uhammad 'hamin 'hawan in 9amarudin

12151/1

0ULLI#A% O) SCIENCE INTERNATIONAL ISLAMIC UNI"ERSIT# MALA#SIA