I. Title of Experiment : IODOFORM

II. Day, Date of experiment : Friday, April 26th, 2013

III. Purpose of experiment :

- Able to synthesize compound iodoform

- Able to purity iodoform by recrystallization

IV. Basic Theory

Iodoform included on haloform compounds other than chloroform and bromoform.

Haloform can be formed when the halogen is reacted with methyl ketone compounds,

halogenated α so that it can be used as a basis for iodoform test unruk methyl ketone

compounds. Reaction mechanisms, namely:

Iodoform (CHI3) is a compound formed from the reaction between iodine under

alkaline conditions with an organic compound having a methyl ketone group (CH3-CO-),

such as acetaldehyde and acetone or if diooksidasi produce a compound having a methyl

ketone group, such as ethanol. In the use of iodine iodoform reaction (I2) and alkali hydroxide

solution (NaOH or KOH) to produce iodoform. Equation is expressed as follows:

Secondary alcohol with ethanol produces acetaldehyde can be oxidized so as to form

iodoform when treated with sodium hipoiodit.

Iodoform obtained in the form of yellow crystals, with a melting point of 120 ° C and

has a characteristic odor. Iodoform can be used as a disinfectant and antiseptic outside. With

a similar reaction, sodium hypochlorite and sodium hiprobromit each produce chloroform

(CHCl3) and bromoform (CHBr3). These reactions known as haloform reaction.

Recrystallization 

Recrystallization is a purification crystallized solids are returned from the fluid

solvent or solvent mixture, dissolve the crystals in hot solvent (or solvent mixture) and then

slowly cooling the solution to form a pure crystal.

Recrystallization purpose:

1. Remove debris generated during both mechanical and physical reactions.

2. Get a good crystal.

 Recrystallization process consists of::

1. Pure substances not dissolve in a suitable solvent at or near the boiling point.

2. Filter the hot solution of particles / dirt / insoluble materials.

3. Indwelling hot solution to cool, forming crystals.

4. Separation of crystals from the mother liquor.

5. Drying

V. Tools and Materials

Tools

a. Erlenmeyer 200 mL

b. Graduated cylinder

c. Buchner funnel

d. Glass funnel

e. Electric stove

f. Filter paper

g. Watch glass

h. Spatula

i. Pipettes

Materials

a. Iodium

b. Acetone

c. NaOH 2 N

d. Alkohol

e. Aquades

2.5 g iodin + 2.5 mL aceton + 5 mL aquades

Precipitate

Filtrate

Iodoform Crystal

• Entered and shaken Erlenmeyer• 2 to added NaOH precipitates a yellow• Added 125 mL of water.• The precipitate is filtered• The precipitate was washed with water

Entered into Erlenmeyer• Added a few mL of ethanol• Electric heaters warmed above• Shaken to precipitate soluble• The solution was filtered.

• Left cold• added 12.5 mL of water• The solution was stirred• The precipitate is filtered• The precipitate was washed with ethanol• crystals are dried in a desiccator

Melting point + smell

VI. Procedure

Weighed the mass

Determined the melting point

VII.Data of Experiment

Procedure Result Hypothesis

2.5 g iodin + 2.5 mL aceton + 5 mL aquades

Precipitate

Filtrate

Iodoformrm Crystal

• Entered and shaken Erlenmeyer• 2 to added NaOH precipitates a yellow• Added 125 mL of water.• The precipitate is filtered• The precipitate was washed with water

Entered into Erlenmeyer• Added a few mL of ethanol• Electric heaters warmed above• Shaken to precipitate soluble• The solution was filtered.

• Left cold• added 12.5 mL of water• The solution was stirred• The precipitate is filtered• The precipitate was washed with ethanol• crystals are dried in a desiccator

Melting point + smell

Weighed the massDetermined the melting point

Iodoform crystal: blackish brown

Acetone: colorless

Aquades: colorless

Iodium crystal + acetone + aquades:

brown solution like betadine

Added by NaOH until the color of

solution is yellow and occur yellow

precipitate

V NaOH: 16 mL

residue color is yellow while filtrate is

colorless

heated until the color orange

filtrated and formed crystal

Added by water, filtrated the

precipitate and washed by ethanol.

Crystal color: yellow

Mass: 0.8 grams

Ethanol dissolved in Iodoform

Melting point of iodoform: 122O C

Iodoform crystal mass: 0.8 grams

Crystal color: yellow

VIII. Analysis and Discussion

At this time the practicum was making iodoform namely by reacting acetone, iodine

and NaOH. This reaction is an oxidation-reduction reaction that involves an increase and

decrease in oxidation. The first step taken 5 ml clear colorless acetone, 5 ml of water and 5 g

of iodine taken black is introduced into the Erlenmeyer flask. The solution was then shaken.

Reactions that occur are:

Once mixed, then ± 16 mL NaOH is added slowly until the solution is yellow.

Function of the addition of NaOH is the giver of alkaline in reaction iodoform iodoform and

produces yellow crystals. In addition, NaOH also acts as a nucleophile that attacks the

carbonyl atom to form a halogenated ketones and ion CI3 that aren’t stabil formed CHI3

(iodoform). Reaction that occur is:

Dissolve then added 125 ml of water. The purpose of the addition of 125 mL

of water immediately after the yellow crystals formed intention to dilute NaOH

possible and to prevent excess hydrolysis velocity iodoform formed. Results obtained

yellow crystals and has been added to the water immediately filtered with a Buchner

funnel. Then the crystals are washed until the filtrate did not react alkalis, or free

NaOH as the rest of NaOH in the crystal can cause decomposition of iodoform on

crystallization time with alcohol.

After filtration with a Buchner funnel and then performed recrystallization

(purification). Recrystallization is a purification of solids which dissolve in hot

conditions in a particular solvent, but in the cold or at room temperature, or crystal

substance will occur. In this experiment used solvent ethanol.

Iodoform incorporated into erlenmeyer. Iodoform then dissolved with a few

mL of ethanol. Due to the flammable nature of ethanol using a closed Erlenmeyer

with funnel and covered with wet cotton to avoid the evaporation of ethanol .. The

purpose of the provision is to dissolve the ethanol perfect crystalline iodoform.

Because ethanol is basically a solvent of iodoform.

Once diluted with ethanol and then heated on the stove while shaken

electricity, heating aims to assist the process of dissolution between ethanol and

iodoform. Having seen a perfect iodoform dissolved in ethanol and then filtered.

Results of screening that are above the filter paper is yellow iodoform dirty yet still

pure. While the solution is left to cool accommodated which will form crystals that

berarna yellow iodoform. Once cool, add 12, 5 mL of water. The solution is then

stirred to precipitate iodoform perfectly. The precipitate was then filtered with a

Buchner funnel and washed with a few drops of iodoform cold ethanol.

Recrystallization results are then stored in a desiccator ± 3 days. Once dry, the

weight of iodoform then weighed at 0.8 g. Based on the results of the calculation are

obtained% yield of :

% rendemeniodoform= gramgram teoritis

×100 %

% rendemeniodoform= 0,812,192

×100 %

% rendemeniodoform=6.56%

% The resulting yield is very small which caused mass in iodoform can be very small

due to a lot of the time attached to the manufacturing process as attached to the filter paper.

And then we determine the melting point is 122oC while theoretically the melting

point of Iodoform is 120o C it’s because the room temperature that not stabil.

X. Conclussion

Based on the experimental results we obtained it can be concluded that the:

1. Iodoform can be made or disintetis of acetone with the crystallization process.

2. Iodoform has the form of yellow crystals and has a distinctive odor.

3. Iodoform that we obtained is 0,8 gram and the melting point is 122oC

XI. Answering Questions

1. Write the equation for the reaction in the experiment above!

2. Explain how halogenated for making this addition to iodine iodoform eg by chlorine

(Cl)?

3. Between to acetone, iodoform can also be made from ethanol. Explain the reason!

Because if the ethanol is oxidized to produce compounds that have a methyl group

aldehyde.

4. Explain how to speed up the dissolution of iodine in acetone!

5. Acetone is reacted with solid iodine and distilled water added. Then shaken then

added NaOH so quickly dissolve iodine

6. Test the solubility of iodoform in water! Whether water can be used as a solvent for

recrystallization iodoform? Explain!!

7. Iodoform is not soluble in cold or hot water so it can not be used as a solvent for

recrystallization iodoform. Needed due to recrystallization solvent soluble in hot

conditions, but in the cold or at room temperature, or crystal substance will occur

8. Calculate the percentage of results that you obtained!

Calculation

mol I 2=massa

Mr

mol I 2=5 gram

254 gram /mol

mol I 2=0,0197 mol

massa aseton=ρaseton × v

massa aseton=0,792g

mL×5 mL

m assaaseton=3,96 gram

mol aseton=massaMr

mol aseton= 3,96 gram58 gram /mol

mol aseton=0,0683 mol

mol NaOH=Nn

× v

mol NaOH=21

×16 ml

mol NaOH=32 mmol=0,032 mol

Reaction:

3I2 + CH3COCH3 CH3COCI3 + 3HI

Initial: 0,0197mol 0,0683 mol - -

Reaction:0,0197 mol 0,0066 mol 0,0066 mol 0,0197 mol

Leftovers: - 0,0617 mol 0,0066 mol 0,0197 mol

CH3COCH3 + NaOH CHI3 + CH3COONa

Initial : 0,0617 mol 0,0320 mol - -

reaction : 0,0320 mol 0,0320 mol 0,0320 mol 0,0320 mol

Left over : 0,0297 mol - 0,0320 mol 0,0320 mol

massa iodoform=mol × Mr . iodoform

massa iodoform=0,032 mol × 381

massa iodo form=12,192 gram

% rendemeniodoform= gramgram teoritis

×100 %

% rendemeniodoform= 0,812,192

×100 %

% rendemeniodoform=6.56%

9. Give the formula of ethyl acetate, propanol, methanol, n-butyl alcohol, sec-butyl alcohol, 4-

methyl-2-pentanol, and 2-pentanone. Whether the compounds positive iodoform test??

10. Where is lies the possibility of failure the manufacture of iodoform this?

a. Failures can be occur if the atmosphere too alkaline

b. Reaction between acetone and iodium less than perfect, wherein do not everything

is forming iodoform.

c. Weighing improper.

REFERENCES

Fessenden & Fessenden. 1986. Kimia Organik Edisi 3.New California: Massachuset.

(Terjemahan. 1982. Kimia Organik. (ed. Ke 3).Jakarta: Erlangga)

Tim penyusun: 2012. Panduan Praktikum Dasar-dasar Kimia Organik 1. Unesa:

Unipress.

Clark, Jim. 2007. Reaksi Triiodometana (Iodoform) dengan Aldehid dan Keton.

Online,http://www.chemistry.org/materi_kimia/sifat_senyawa_organik/

aldehid_dan_keton/reaksi_triiodometana_iodoform_dengan_aldehid_dan_keton/.

Diakses pada 8 April 2012.