Bonding with ColorChemistry and OutreachOpportunities of Tie Dye

Anne E. MoodyTruman State Universityamoody@truman.edu

AEMoody: Truman State U

Truman Freshmen 2007

AEMoody: Truman State U

Color is Everywhere!

AEMoody: Truman State U

Color Results from Interaction of Light and Matter

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Must BOND Dyes to Clothes

AEMoody: Truman State U

Natural Dyes

Tyrian Purple From Shellfish

N

NO

OH

H

Br

Br

Kermesic Acid From Insects

HOOC

HO

CH3 O

O OH

OH

OH

AEMoody: Truman State U

Molecular Structure Determines Color of Matter

Note extended conjugated pi systems in these synthetic dyes:

OH

NN

SO3- Na+

Orange II

Martius Yellow

O- NH4+

NO2

O2N

AEMoody: Truman State U

Fiber Structure Determines Interactions with Dyes

N

H

CH

R

CO

NH CH

R'

CO

NH CH

R"CO

n

Wool has many reactive sites in its structure:

AEMoody: Truman State U

Cheaper Fabric Structures

• In Cotton, R = H• In Acetate Rayon, R= C(O)CH3

O

OO

HOOR

CH2OH

OO

CH2OH

OHRO

n

AEMoody: Truman State U

Vat Dyes depend on Mechanical Retention and

Redox Chemistry

N

NO

OH

H

Na2S2O4 + NaOH

O2 N

N

H

H

O- Na+

O- Na+Indigo Indigo white

blue form, H2O insoluble Leuco form, H2O soluble

AEMoody: Truman State U

Fiber Reactive DyesIn General: W-D-Q-RG-X

Where: W = water solubilizing groupsD = Chromophore of DyeQ = Bridging GroupRG = Reactive GroupX = Leaving Group

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Procion Synthetic Dye Example

• Fiber Reactive Dye • Covalently Bonds to Fabric

NN

NCl

ClSO3

-Na+

NH

SO3-Na+

O

ONH

Procion Blue

AEMoody: Truman State U

“Stylized” Procion Dye Reaction with Cotton

OH OH OH OH OH

Base

O O O O O

Dye-Cl

O O O O O

Dye Dye Dye Dye Dye

Pretend this is cotton:

Deprotonated "cotton":

Dye BONDED to "cotton":

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Closer Look at Dye-Fabric Bond Formation

NN

NWDQ Cl

Cl

O CelNN

NWDQ Cl

Cl

OCel

NN

NWDQ OCel

Cl

+ Cl

AEMoody: Truman State U

Hydrolysis of C-Cl of Dye

NN

NWDQ Cl

Cl

O HNN

NWDQ Cl

Cl

OH

NN

NWDQ OH

Cl

+ Cl

AEMoody: Truman State U

Acid-Base Chemistry Inactivates Dyes

NN

NN Cl

Cl

O H

WD

H

NN

NN Cl

Cl

WDH OH

NHN

NN Cl

Cl

WD+ HO

unreactive

AEMoody: Truman State U

Today’s Experiment

• Your T-shirt starts out very clean and dry!

• It goes into our bucket of base solution and now it is very wet and basic.

• We’ll wring it out when we give it to you!

AEMoody: Truman State U

Your Task for Today• Twist and fold the damp, basic

shirt in particular patterns; secure it with rubber bands.

• Apply the dyes using squirt bottles….

• Place wet, dyed shirt in zip-lock bag and let reactions proceed.

AEMoody: Truman State U

Patience with the Experiment!• Wait 24 hours!

• Wash in hot water with dish soap; dry in hot dryer.

• Enjoy cool shirt! ;-)

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Tie Dye and Chemistry are FUN!

• Fun and creative outlet• Excellent outreach activity• Excellent fund-raising activity• Chemistry at many levels

;-)