Synthesis and physicochemical properties of non-ionic and cationic - - PowerPoint PPT Presentation

Synthesis and physicochemical properties of non-ionic and cationic surfactants derived from methionine

Nausheen Joondan Anousha Radhan Sabina Jhaumeer Laulloo Prakashanand Caumul

Department of Chemistry Faculty of science University of Mauritius

Surfactants

Key ingredients in detergents and cosmetics

N+ Br-

Cetyltrimethylammonium bromide (CTAB)

Na+ S O O O O-

Sodium dodecyl sulfate (SDS)

Good antibacterial activity Good foaming ability Cleaning property Benefits Toxic Antimicrobial resistance Non-biodegradable Petroleum based chemicals Drawbacks

Amino acid based surfactants

 Consists of an amino acid head group linked to a long fatty acid/alcohol chain  Can be used as alternative to conventional surfactants

Advantages Use of renewable raw materials for their synthesis Biodegradable Environment friendly Non-toxic

Examples of amino acid surfactants reported

N O O

n

Proline-based surfactants n= 15 n= 7, 9, 11, 13, 15

O O N I- n R R'

Aromatic amino acid-based quaternary ammonium surfactants R= R'= H; n= 9, 11, 13, 15 R=OH, R'= H; n= 9, 11, 13, 15 R= R'= OH; n= 9, 11, 13, 15

O O NH3

R Cl- n

R' Aromatic amino acid surfactants R=R’= H, n=7-19 R=OH, R’=H, n=7-21 R= R’=OH,’ n=7-13

Joondan, N., Jhaumeer-Laulloo, S., Caumul, P., 201

• 4. Microbiol. Res. 1

69, 675-685 Joondan, N., Caumul, P., Akerman, M., Jhaumeer-Laulloo, S., 201 5 Bioorg. Chem. 58, 1 1 7-1 29 Joondan, N., Jhaumeer-Laulloo, S., Caumul, P., 201

• 5. J. Surfactants Deterg. 1

8, 1 095-1 1 04 Joondan, N., Jhaumeer-Laulloo, S., Caumul, P., Marie, D.E.P., Roy, P., Hosten, E., 201

• 6. Colloids. Surf. A. Physicochem. Eng. Asp. 51

1 , 1 20-1 34 Joondan, N., Caumul, P., Jhaumeer-Laulloo, S., 201

• 7. J. Surfactants Deterg. 20, 1

03-1 1 5 Baczko, K., Larpenta C., Lesot, P., 2004. Tetrahedron: Asymmetry, 1 5, 971 –982

Sulfur-based Amino acid surfactants

NH2 S O HO

Cysteine Methionine

S S NH3 N H O

11

Cl-

NH3Cl- O HN

11

S S N H O OH

n

H N OH O

n

S NH O N CH3 CH3 H3C

Cl-

S R HN O N CH3 CH3 C H3

Cl-

R 10

10

Branco, M.A., Pinheiro, L., Faustino, L., 201

• 5. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 480, 1

05-1 1 2 Fan, H., Han, F., Liu, Z., Qin, L., Li, Z., Liang, D., Ke, F., Huang, J., Fu, H., 2008. Journal of Colloid and Interface Science, 321 , 227-234 Pinazo, A., Diz, M., Solans, C., Pes, M.A., Erra, P., Infante, M.R., 1

• 993. Journal of American Oil Chemists’ Society, 70, 37

Yoshimura, T., Sakato, A., Tsuchiya, K., Ohkubo, T., Sakai, H., Abe, M., Esumi, K., 2007. Journal of Colloid and Interface Science, 308, 466-473

However, there is very little report

• n

surfactants derived from methionine

Synthesis of methionine O-alkyl esters and their hydrochloride derivatives

1a: n= 8; 1b: n=10; 1c: n=12 2a: n= 8; 2b: n=10; 2c: n=12

Chain length Methionine esters % Yield Methionine ester hydrochloride % Yield 8 1a 81 2a 70 10 1b 66 2b 62 12 1c 54 2c 50

CnH2n+1OH

PTSA Refluxing toluene/ 48 hr OCnH2n+1 O NH2 NH2 S O OH S OCnH2n+1 O NH3Cl- S

HCl

1.0 1.5 2.0 2.5 3.0 3.5 4.0 ppm 0.827 0.855 0.880 1.247 1.278 1.559 1.586 1.614 1.730 1.758 1.762 1.785 1.790 1.818 1.975 1.995 2.006 2.027 2.083 2.571 2.599 2.630 3.526 3.545 3.558 3.578 4.062 4.090 4.114 4.117

3.15 10.55 4.45 1.01 0.99 3.00 1.93 1.05 1.92

1H NM R spectrum

a b c, i f f h

O O NH2

a b c d e f

S

g h i

g e d

13C NM R spectrum a i d CDCl3

O O NH2

a b c d e f

S

g h i

e f h g

IR spectra

Ester peak

O O NH2 S

Synthesized compounds

O O NH2 S O O NH2 S O O NH2 S

O O NH3 S O O NH3 S O O NH3 S

Cl- Cl- Cl-

Non-ionic surfactant Methionine ester Cationic surfactant Methionine ester hydrochloride

Physicochemical properties

Critical micelle concentration

Conductivity measurements Pyrene fluorescence measurements

OCnH2n+1 O NH3 S

Cl-

OCnH2n+1 O NH2 S

Comparing the CMC of the methionine esters with their ester hydrochloride derivatives

Chain length Methionine esters CMC (mM) Methionine ester hydrochloride CMC (mM) 8 1a 1.28 2a 4.74 10 1b 0.63 2b 3.42 12 1c 0.25 2c 2.31

• In both series, the CMC was found to decrease with increasing chain length of the

surfactants.

• The CMC of the methionine esters were lower than their corresponding ester

hydrochloride derivatives.

• The ester hydrochlorides have less tendency to micellise due to repulsion between

their cationic head groups

Physicochemical properties

The Krafft T emperature (TK) The minimum temperature at which surfactant can form micelles in aqueous solution

Obtained from the plot

• f

conductivity

• f

surfactant solution (above CMC) versus temperature

Effect of chain length on the Krafft temperature.

Methionine ester hydrochloride Tk (°C) 2a 23 2b 25 2c 29 CTAB (cetyl trimethylammonium bromide) 22

The ester hydrochloride derivatives showed an increase in the Krafft temperature with increasing chain length showing that the surfactants with longer chain length has a tendency to micellise at a much higher temperature

Conclusion

 The methionine esters with varying chain lengths as well as their hydrochloride derivatives were successfully synthesized.  The CMC of the methionine esters and their hydrochloride derivatives were found to decrease with chain length, as observed for previously reported surfactants.  The methionine ester hydrochloride derivatives have a less tendency to micellise compared to their non-ionic ester derivatives due to the repulsion caused by their cationic head groups.  An increase in chain length of the methionine ester hydrochloride caused an increase in the Krafft temperature of the surfactants, suggesting that the methionine surfactants with longer chain length micellise at higher temperatures