A PRESENTATION ON

SYNTHESIS OF TWEEN-BASED BIOCOMPATIBLE IMIDAZOLIUM TRICATIONIC ROOM TEMPERATURE

IONIC LIQUIDS (RTILS)

CENTRAL UNIVERSITY OF GUJARAT

Souvik Bagchi(Enrollment No.-CUG/2014/1096) School of Chemical Sciences (SCS)Central University of Gujarat Gandhinagar, India

Dessertation on M.sc project Under the supervision ofDr. Dhananjoy Mondal (Faculty, SCS)Central University of GujaratGandhinagar, India

INTRODUCTION

o Ionic liquids (ILs) are ionic salt that are liquid below 100°C.

o ILs have emerged as an environmentally friendly alternative to the volatile organic solvents.

o ILs possess unique tunable physicochemical properties like high viscosity, low vapour pressure, non-flammability

o ILs find applications in various fields like catalysis, electrochemistry, spectroscopy, and in material science.

DIFFERENT TYPES OF RTILS

NHN NH NH2

NR R

R

R

PRR

RR

SO

OOOR

alkyl sulfate tosylate methanesulfonate hexafluorophosphate tetrafluoroborate

S

O

O

OSO

OOCR3 PF6 BF4

imidazolium pyridinium pyrrolidinium tetraalkylphosphonium quaternery ammonium

TOTAL REACTION SCHEME:

O

O

O

OHO

OH

OOH

OCH2(CH2)15CH3

Ow

x

y

z

O

O

O

OO

O

OO

OCH2(CH2)15CH3

O

SOO

CH3

SO

O

CH3

SO

O

H3C

w

x

yz

Et3N,CH2Cl2

0 °C, rt

O

OOON

N

ON

OCH2(CH2)15CH3

ONH3C

NCH3

NCH3

3OMs

x

y

z

w

1-methyl imidazolium CH3CN

75 °C 48h

O

OOON

N

ON

OCH2(CH2)15CH3

ONH3C

NCH3

NCH3

3BF4

x

yw

z

NABF4

H2O,rt

tween 20 trimesylate precursor

tween 20-tri (3-methylimidazolium)trimesylatetween 20-tri (3-methylimidazolium)tetrafluoroborate

Step 1

•Typical procedure for synthesis of trimesylate precursors

Step 2

•Synthesis of Tween-60-tri (1-methylimidazolium) trimesylate [Tw60(mim)3][OMs]3

Step 3

•Synthesis of Tween-60-tri (1-methylimidazolium) tetrafluoroborate [Tw60(mim)3][BF4]3

Typical procedure for synthesis of tri-cationic RTILs

STEP –I:

O

O

O

OHO

OH

OOH

OCH2(CH2)15CH3

Ow

x

y

z

O

O

O

OO

O

OO

OCH2(CH2)15CH3

O

SOO

CH3

SO

O

CH3

SO

O

H3C

w

x

yz

Et3N,CH2Cl2

0 °C, rt

tween 20 trimesylate precursor

The first step involves the mesylation of three hydroxyl groups of Tween 60.

The mesylation was carried out by treating the Tween 60 with methyl sulfonyl chloride and triethylamine initially at 0° C and then it was kept for 16 h at room temperature with continuous stirring.

STEP-II :

O

O

O

OO

O

OO

OCH2(CH2)15CH3

O

SOO

CH3

SO

O

CH3

SO

O

H3C

w

x

yz

O

OOON

N

ON

OCH2(CH2)15CH3

ONH3C

NCH3

NCH3

3OMs

x

y

z

w

1-methyl imidazolium CH3CN

75 °C 48h

trimesylate precursor

tween 20-tri (3-methylimidazolium)trimesylate

Then after getting the step-I mesylated intermediate, the product was treated with 1- methyl imidazolium for 28 h at 80°C.

The product was purified with diethyl ether to remove the unreacted starting material to get the Tween-60-tri (1-methylimidazolium) trimesylate.

STEP-III:

O

OOON

N

ON

OCH2(CH2)15CH3

ONH3C

NCH3

NCH3

3OMs

x

y

z

w

O

OOON

N

ON

OCH2(CH2)15CH3

ONH3C

NCH3

NCH3

3BF4

x

yw

z

NABF4

H2O,rt

tween 20-tri (3-methylimidazolium)trimesylatetween 20-tri (3-methylimidazolium)tetrafluoroborate

In this step the product obtained in step-II was further subjected to anion metathesis and treated with NaBF4. to exchange the mesyl anion with sodium tetrafluoroborate.

CHARACTERIZATION

Wavelength cm-1

 

Wavelength cm-1

 

% T

rans

mitt

ance

 

Tween-60 Tween-60 trimesylate Wavelength cm-1

 

Wavelength cm-1

 

% T

rans

mitt

ance

 

% T

rans

mitt

ance

 % T

rans

mitt

ance

 

Result and Discussion Our first target was to prepare a trimesylate precursor. To that target, we

envisioned the use of surfactant Tween 60 as our starting material. We used triethylamine and methyl sufonyl chloride for preparing the trimesylate precursor and it was confirmed by TLC and IR studies.

Then we replace the –Oms group by Methyl Imidazole group by reacting the step-I product with 1-Methyl Imidazole and refluxed with acetonitrile. The product so formed is brownish viscous Tween-60-tri (1-methylimidazolium) trimesylate and it was confirmed by TLC and IR studies.

In the third and final step we put the purified step II product for metathesis reaction and exchange the (Oms)- ions with BF4

- by treating it with NaBF4. The reaction was confirmed by IR studies.

[1] Avinash A. Chaugule, Ashif H. Tamboli, Faheem A. Sheikh, Wook-Jin Chung, Hern Kim, “Glycerol functionalized imidazolium tri-cationic room temperature ionic liquids: Synthesis, properties and catalytic performance for 2-azidoalcohol synthesis from epoxide”, Journal of Molecular Liquids, 208(2015) 314-321

[2] Matthew D. Green and Timothy E. Long, “Designing Imidazole based Ionic Liquid monomers for emerging Technologies”, Journal of Macromolecular Science, Part C, Polymer Reviews, 49:291-314, 2009

[3] Xavier Creary and Elizabeth D. Willis, “Preparation of 1- Butyl-3-Imidazolium Tetrafluoroborate”, Organic Synthesis, Vol. 82, p. 166-169 (2005); Coll. Vol. 11, p. 859-861(2009)

REFERENCES

THANKS TO ALL