ORIGINAL ARTICLE

Creation of Novel Green and Sustainable Gemini-Type CationicsContaining Carbonate Linkages

Taisuke Banno • Kazuo Kawada • Shuichi Matsumura

Received: 23 March 2010 / Accepted: 8 July 2010 / Published online: 5 August 2010

� AOCS 2010

Abstract Novel gemini-type cationics containing

carbonate linkages as biodegradable and chemically recy-

clable segments were designed and synthesized by a green

process. The carbonate linkages were introduced into only

the hydrophobic moiety or in both the hydrophobic and

linker moieties of gemini-type cationics. They showed

higher surface activities, such as a low critical micelle

concentration value, a surface tension lowering, and a high

adsorption efficiency, when compared to the corresponding

single-type cationics. Also, the gemini-type cationics con-

taining carbonate linkages in both the hydrophobic and the

linker moieties showed stronger antimicrobial activities

when compared to those only in the hydrophobic moiety. It

was found that some gemini-type cationics containing

carbonate linkages showed higher biodegradability com-

pared to the conventional gemini-type cationics. The bio-

degradability of the gemini-type cationics decreased when

a carbonate linkage was introduced into the hydrophobic

moiety rather than the linker moiety. However, some

gemini-type cationics containing carbonate linkages both

in the hydrophobic and linker moieties showed ready bio-

degradability. The gemini-type cationics containing car-

bonate linkages in the hydrophobic moiety showed

chemical recyclability by a lipase (E.C. 3.1.1.3).

Keywords Antimicrobial activity � Biodegradability �Carbonate linkage � Chemical recyclability � Gemini-type

cationic surfactant � Green chemistry � Lipase � Surface

activity

Introduction

In recent years, the establishment of the new field of

green chemistry has been recognized as a necessary goal

for sustainable development. This greening of chemistry

has realized the discovery and development of new

synthetic routes using renewable feedstocks, reaction

conditions and catalysts for improved selectivity and

energy minimization, and the design of bio-/environ-

mentally compatible chemicals. Based on these concepts,

some green surfactants have been designed and synthe-

sized using bio-based or potentially bio-based starting

materials, such as amino acids, fumaric acid, maleic

acid, and aconitic acid [1–3].

The syntheses and properties of gemini-type (dimeric)

cationics consisting of two hydrophobic alkyl chains and

two quaternary ammonium groups covalently attached

through a linker moiety have been extensively studied by

many researchers. The first report of dimeric cationics in

the scientific literature was published by Bunton et al. [4].

The term ‘‘gemini-surfactants’’ was coined for these

dimeric surfactants by Menger et al. [5, 6]. It has been

reported that gemini-type cationics exhibited superior

properties when compared to those of conventional single-

type cationics, such as lower critical micelle concentration

(CMC), surface tension lowering, higher adsorption effi-

ciency, and so on [7–11]. Carbohydrate-based gemini-type

surfactants with two tertiary amino groups have been

synthesized and characterized [12–14]. Also, gemini-type

T. Banno � S. Matsumura (&)

Department of Applied Chemistry, Faculty of Science

and Technology, Keio University, 3-14-1, Hiyoshi,

Kohoku-ku, Yokohama 223-8522, Japan

e-mail: matumura@applc.keio.ac.jp

K. Kawada

Department of Chemistry, School of Science,

Kitasato University, 1-15-1, Kitasato,

Sagamihara 228-8555, Japan

123

J Surfact Deterg (2010) 13:387–398

DOI 10.1007/s11743-010-1224-5

cationics showed strong antimicrobial activities against a

broad range of microorganisms [15–17]. Gemini-type cat-

ionics can be regarded as green surfactants because they

show higher functionalities that lead to a reduction in their

consumption. This saves carbon resources and production

energies. However, there are few reports on the biode-

gradabilities of gemini-type cationics. Furthermore, cat-

ionics are generally resistant to biodegradation due to the

lack of a primary degradation site in the molecule [18].

Due to the water-soluble nature of surfactants, they are

generally difficult to recover or reuse. Once they are

discharged as drainage into the environment, they

are widely diffused if they are not biodegradable. Thus, the

development of gemini-type cationics with an improved

biodegradability using renewable resources by an envi-

ronmentally benign process is needed with respect to the

establishment of green and sustainable chemistry. It has

been reported that gemini-type cationics containing ester

linkages in the hydrophobic moiety were biodegraded by

activated sludge [19–21]. However, ester linkages are

generally labile to hydrolysis, particularly under alkaline

conditions. More hydrolytically stable and biodegradable

cationics are, thus, needed. Furthermore, gemini-type cat-

ionics should be chemically recyclable, particularly in the

industrial field.

The carbonate linkage is hydrolyzed by lipase in aque-

ous media to produce two hydroxyl groups with the evo-

lution of carbon dioxide. However, it is advantageous for

surfactants that, in the absence of lipase, carbonate linkages

are more stable than ester linkages in aqueous media

because they are generally used in aqueous solution.

A nonionic surfactant containing a carbonate linkage was

first reported by Stjerndahl and Holmberg [22]. The syn-

thetic polyoxyethylene-type nonionic surfactants contain-

ing carbonate linkages showed both hydrolytic stability and

biodegradability. We previously reported that single-type

cationic surfactants containing a carbonate linkage showed

antimicrobial activities, chemical recyclability, and biode-

gradability, in addition to good surfactant properties [23].

We also reported that biodegradability was improved by

the introduction of the carbonate linkage into the linker

moiety of gemini-type cationics [24].

In this report, novel gemini-type cationic green surfac-

tants containing carbonate linkages were designed and

synthesized by a green process. Figure 1 shows the design

of gemini-type cationics containing carbonate linkages as

biodegradable and chemically recyclable segments. The

carbonate linkages were introduced into only the hydro-

phobic moiety or in both the hydrophobic and linker

moieties of gemini-type cationics. Their surfactant prop-

erties, biodegradabilities, chemical recyclabilities, and

antimicrobial activities were evaluated.

Experimental Procedures

Materials and Methods

Diphenyl carbonate, 1-alkanols, 3-N,N-dimethylamino-

1-propanol, 1-N,N-dimethylamino-2-propanol, and methyl

iodide were purchased from Tokyo Kasei Kogyo Co., Ltd.

(Tokyo, Japan) and used as received. Triethylamine (Et3N)

was purchased from Sigma-Aldrich Co., Inc. (St. Louis,

MO, USA). 1,3-Diiodopropane was purchased from Wako

Chemical Co., Ltd. (Osaka, Japan) and used as received.

Immobilized lipase (E.C. 3.1.1.3) from Candida antarctica

[lipase CA: Novozym 435, a lipase (lipase B) from Can-

dida antarctica produced by submerged fermentation of a

genetically modified Aspergillus oryzae microorganism

and adsorbed on a macroporous acrylic resin, having

10,000 PLU g-1 (propyl laurate units: lipase activity based

on ester synthesis)] was kindly supplied by Novozymes

Japan, Ltd. (Chiba, Japan). The enzyme was dried under

vacuum (3 mmHg) over P2O5 at 25 �C for 2 h before use.

The purity and chemical structure of the synthetic com-

pounds were analyzed by thin-layer chromatography

(TLC), elemental analysis, and 1H nuclear magnetic reso-

nance (NMR) spectroscopy. TLC was carried out using

Merck silica gel 60 F254 plates (Merck Ltd., Darmstadt,

Germany). 1H NMR spectra were recorded with a Lambda

Fig. 1 Design of novel green

and sustainable gemini-type

cationics containing carbonate

linkages

388 J Surfact Deterg (2010) 13:387–398

123

300 Fourier Transform Spectrometer (JEOL Ltd., Tokyo,

Japan) operating at 300 MHz.

Preparation of n-Alkyl = N,N-

Dimethylaminoalkyl = Carbonate (CnX)

The n-alkyl = N,N-dimethylaminoalkyl = carbonate (CnX)

was prepared according to Scheme 1. The CnX was prepared

by the one-pot successive carbonate exchange reaction of

diphenyl carbonate 1 with 1-alkanol followed by reaction

with N,N-dimethylaminoalcohol in the presence of Et3N

according to previous work [23]. The molecular structure was

analyzed by 1H NMR spectroscopy and elemental analysis.

Their yield, the assignment of 1H NMR, and elemental

analysis are summarized in Table 1.

Preparation of Gemini-Type Cationics Containing

Carbonate Linkages in the Hydrophobic Moiety (GnX)

The gemini-type cationics, propane-1,3-bis(alkyl = N,N-

dimethylammoniumalkyl = carbonate) diiodide (GnX),

was prepared according to Scheme 1. GnX was prepared

by the reaction of CnX (0.44 mmol) and 1,3-diiodopropane

(0.20 mmol) in dry acetonitrile (2.0 mL) in a screw-capped

vial at 80 �C for 1 day with stirring. After the reaction, the

solvent was removed by evaporation under reduced pres-

sure to obtain the crude product. Purification was carried

out by recrystallization from ethyl acetate (1.0 mL) to

obtain the GnX in 68–86% yield as pale yellow crystals.

The molecular structure was analyzed by 1H NMR spec-

troscopy and elemental analysis. Their yield, melting point

Scheme 1 Synthesis and

chemical recycling of GnX

Table 1 Synthesis and analytical data of CnX

CnX Yield 1H NMR (300 MHz, CDCl3) C% H% N%

(%) d (ppm) Found Calcd. Found Calcd. Found Calcd.

C8Pr 91 0.88 (3H, t, J = 6.9 Hz), 1.20–1.42 (10H, m),

1.66 (2H, tt, J = 7.2, 7.5 Hz), 1.84 (2H,

tt, J = 7.2, 7.5 Hz), 2.23 (6H, s),

2.36 (2H, t, J = 7.5 Hz), 4.12 (2H, t,

J = 7.2 Hz), 4.18 (2H, t, J = 7.5 Hz)

64.68 64.83 11.21 11.27 5.40 5.40

C10Pr 85 0.88 (3H, t, J = 6.9 Hz), 1.19–1.42 (14H, m),

1.66 (2H, tt, J = 7.5, 7.5 Hz), 1.84 (2H, tt,

J = 7.5, 7.5 Hz), 2.23 (6H, s), 2.36 (2H, t,

J = 7.5 Hz), 4.12 (2H, t, J = 7.5 Hz),

4.18 (2H, t, J = 7.5 Hz)

66.68 66.86 11.27 11.57 4.96 4.87

C12Pr 91 0.88 (3H, t, J = 6.6 Hz), 1.17–1.41 (18H, m),

1.66 (2H, tt, J = 6.9, 6.9 Hz), 1.84 (2H, tt,

J = 7.2, 7.5 Hz), 2.23 (6H, s), 2.36 (2H, t,

J = 7.5 Hz), 4.12 (2H, t, J = 6.9 Hz),

4.18 (2H, t, J = 7.2 Hz)

68.36 68.53 11.69 11.82 4.40 4.44

C12iPr 75 0.88 (3H, t, J = 6.6 Hz), 1.17–1.43 (21H, m),

1.66 (2H, tt, J = 6.9, 6.9 Hz), 2.26 (6H, s),

2.27 (1H, dd, J = 6.0, 13.2 Hz), 2.56 (1H, dd,

J = 7.2, 13.2 Hz), 4.11 (2H, t, J = 6.9 Hz), 4.88 (1H, m)

68.49 68.53 11.78 11.82 4.41 4.44

J Surfact Deterg (2010) 13:387–398 389

123

(mp), the assignment of 1H NMR, and elemental analysis

are summarized in Table 2.

Preparation of Gemini-Type Cationics Containing

Carbonate Linkages in Both the Hydrophobic

and Linker Moieties (mG12Pr)

The gemini-type cationics containing carbonate linkages

both in the hydrophobic and linker moieties, 2G12Pr and

3G12Pr, were prepared by the reaction of C12Pr and

di(iodoalkyl) carbonate 3 according to Scheme 2.

Di(iodoalkyl) carbonate was prepared by the reaction of

diphenyl carbonate and iodoalkanol in the presence of

K2CO3 according to the previous report [24]. The 2G12Pr

was prepared by the reaction of C12Pr (0.22 mmol) and

di(2-iodoethyl) carbonate 3a (0.1 mmol) in acetonitrile

(1.0 mL) in a screw-capped vial at 80 �C for 3 days with

stirring. Purification was carried out by recrystallization

from ethyl acetate (1.0 mL) to obtain 2G12Pr in 74% yield

as a pale yellow crystal. In a similar procedure, 3G12Pr

was prepared using di(3-iodopropyl) carbonate 3b in 68%

yield as a pale yellow crystal. The molecular structure was

analyzed by 1H NMR spectroscopy and elemental analysis.

Their yield, mp, the assignment of 1H NMR, and elemental

analysis are summarized in Table 3.

Preparation of Single-Type Cationics Containing

Carbonate Linkages (S12X)

The quaternarization of C12X (1.0 mmol) was carried out

using methyl iodide (1.2 mmol) in dry acetonitrile

(1.0 mL) at room temperature for 30 min with stirring, as

shown in Scheme 3. After the reaction, the solvent and

unreacted methyl iodide were removed by evaporation

under reduced pressure to obtain the crude product. Puri-

fication was carried out by recrystallization from ethyl

acetate (3.0 mL) to obtain S12Pr in 85% yield as a white

crystal. In a similar procedure, S12iPr was prepared using

C12iPr in 87% yield as a white crystal. The molecular

structure was analyzed by 1H NMR spectroscopy and ele-

mental analysis. Their yield, mp, the assignment of 1H

NMR, and elemental analysis are summarized in Table 4.

Preparation of G12Pr-Derived Degradation Product

(3HPr)

In order to evaluate the biochemical oxygen demand

(BOD) biodegradability of the primary degradation prod-

ucts of G12Pr, propane-1,3-bis(N-3-hydroxypropyl-N,N-

dimethylammonium) diiodide (3HPr) was chemically

prepared. The 3HPr was prepared by the quaternarization

Table 2 Synthesis and analytical data of GnX

Cationics Yield mp 1H NMR (300 MHz, CDCl3) C% H% N%

(%) (�C) d (ppm) Found Calcd. Found Calcd. Found Calcd.

G8Pr 86 112–113 0.88 (6H, t, J = 6.6 Hz), 1.16–1.42

(20H, m), 1.67 (4H, tt, J = 6.9,

7.2 Hz), 2.26–2.42 (4H, m),

2.62–2.80 (2H, m), 3.47 (12H, s),

3.64–3.78 (4H, m), 3.88–4.01 (4H,

m), 4.13 (4H, t, J = 6.9 Hz), 4.30

(4H, t, J = 5.7 Hz)

45.90 45.70 7.98 7.92 3.43 3.44

G10Pr 79 125–127 0.88 (6H, t, J = 6.6 Hz), 1.18–1.42

(28H, m), 1.67 (4H, tt, J = 6.9,

7.2 Hz), 2.25–2.43 (4H, m),

2.62–2.80 (2H, m), 3.46 (12H, s),

3.63–3.78 (4H, m), 3.89–4.02 (4H,

m), 4.13 (4H, t, J = 6.9 Hz), 4.30

(4H, t, J = 5.9 Hz)

48.02 48.28 8.33 8.33 3.15 3.22

G12Pr 85 120–122 0.88 (6H, t, J = 6.6 Hz), 1.18–1.43

(36H, m), 1.67 (4H, tt, J = 7.2,

7.2 Hz), 2.26–2.42 (4H, m),

2.62–2.80 (2H, m), 3.46 (12H, s),

3.65–3.76 (4H, m), 3.89–4.01 (4H,

m), 4.13 (4H, t, J = 7.2 Hz), 4.30

(4H, t, J = 5.9 Hz)

50.28 50.54 8.56 8.70 2.97 3.02

G12iPr 68 128–130 0.88 (6H, t, J = 6.6 Hz), 1.18–1.43

(36H, m), 1.52 (3H, d, J = 6.0 Hz),

1.60–1.76 (4H, m), 2.68–3.02 (2H,

m), 3.38–3.62 (12H, m), 3.72–4.34

(12H, m), 5.21–5.38 (2H, m)

50.25 50.54 8.74 8.70 2.82 3.02

390 J Surfact Deterg (2010) 13:387–398

123

of 3-N,N-dimethylamino-1-propanol 4 (1.1 mmol) with

1,3-diiodopropane (0.5 mmol) in dry acetonitrile (1.0 mL)

in a screw-capped vial at 80 �C for 1 day with stirring, as

shown in Scheme 4. Purification was carried out by rep-

recipitation from methanol (1.0 mL, good solvent) and

ethyl acetate (3.0 mL, poor solvent) to obtain 3HPr in 83%

yield as a white crystal. The molecular structure was

confirmed by 1H NMR spectroscopy and elemental

analysis.

3HPr: 1H NMR (300 MHz, CD3OD): d = 2.02 (4H, tt,

J = 10.8, 11.7 Hz, N-CH2-CH2-), 2.30–2.46 (2H, m, N?-

CH2-CH2-CH2-N?), 3.23 (12H, s, 2N?(CH3)2), 3.44–3.61

(8H, m, 4N?-CH2-), 3.70 (4H, t, J = 6.6 Hz, 2-CH2-OH).

Anal. Calcd for C13H32N2O2I2 : C, 31.09; H, 6.42; N, 5.58.

Found: C, 31.31; H, 6.55; N, 5.52. mp 150–151 �C.

Hydrolytic Stability

Hydrolytic stability tests were carried out by dissolving

G12Pr and G12iPr at 5 g L-1 in distilled water and ace-

tate and phosphate buffers (pH 4.0 and 7.0, respectively) at

25 �C for 20 days. Hydrolytic degradation of gemini-type

cationics was analyzed by 1H NMR, and hydrolytic sta-

bility was calculated using the methylene protons adjacent

to the carbonate linkages at d 4.30 ppm of G12Pr and d5.21–5.38 ppm of G12iPr.

Scheme 3 Synthesis of S12X

Table 3 Synthesis and analytical data of mG12Pr

Cationics Yield mp 1H NMR (300 MHz, CDCl3) C% H% N%

(%) (�C) d (ppm) Found Calcd. Found Calcd. Found Calcd.

2G12Pr 74 131–133 0.88 (6H, t, J = 6.6 Hz), 1.18–1.41

(36H, m), 1.58–1.72 (4H, m),

2.20–2.36 (4H, m), 3.48 (12H, s),

3.78–3.91 (4H, m), 4.12 (4H, t,

J = 6.8 Hz) 4.30 (4H, t,

J = 5.6 Hz), 4.34–4.46 (4H, m),

4.86–5.00 (4H, m)

49.27 49.20 8.40 8.26 2.81 2.80

3G12Pr 68 158–159 0.88 (6H, t, J = 6.6 Hz), 1.20–1.42

(36H, m), 1.60–1.72 (4H, m),

2.22–2.37 (8H, m), 3.42 (12H, s),

3.64–3.76 (4H, m), 4.01–4.12 (4H,

m) 4.13 (4H, t, J = 7.1 Hz), 4.30

(4H, t, J = 6.0 Hz), 4.40 (4H, t,

J = 5.3 Hz)

49.88 50.19 8.44 8.42 2.67 2.72

Scheme 2 Synthesis of

di(iodoalkyl) carbonate as a

linker moiety and mG12Pr

J Surfact Deterg (2010) 13:387–398 391

123

Surfactant Properties

The static surface tension was measured using an automatic

digital Kyowa Precise Surface Tensiometer by the CBVP

method (Kyowa Kagaku Co. Ltd., Tokyo, Japan) at 25 �C. The

measurement was carried out using the Wilhelmy vertical plate

technique and a sandblasted glass plate. The test solutions were

aged at 25 �C for at least 1 h before any measurements.

The occupation area of a molecule at a surface (Amin)

was calculated according to the Gibbs adsorption equation.

The surface excess concentration (C) in mol m-2 and the

corresponding Amin in nm2 at the liquid/air interface were

calculated using Eqs. 1 and 2:

C ¼ �1

2:30nRT

dcdlogC

� �ð1Þ

Amin ¼1018

NACð2Þ

where n is a constant and depends upon the individual ions

comprising the surfactant (n = 2 for single-type cationics

and n = 3 for gemini-type cationics) [25, 26], dc/dlogC is

the slope of the surface tension versus concentration curves

below the CMC at a constant temperature, c is the surface

tension in mN m-1, T is the absolute temperature,

R = 8.31 (J mol-1 K-1), and NA is Avogadro’s number.

Biodegradabilities

The biodegradabilities of the cationic surfactants were

evaluated by BOD. The BOD was determined with a BOD

Tester (VELP Scientifica s.r.l., Usmate, MI, Italy) using the

oxygen consumption method according to the Modified

MITI Test [27]. Activated sludge was obtained from a

municipal sewage plant in Yokohama City, Japan. The

BOD-biodegradation (BOD/ThOD) was calculated from

the BOD values and the theoretical oxygen demand

(ThOD).

Enzymatic Degradation and Reproduction for Chemical

Recycling

The enzymatic degradation of gemini-type cationics

containing carbonate linkages was carried out using

immobilized lipase. The enzymatic degradation of

G12Pr (50 mg) was carried out using 100 wt% immo-

bilized lipase CA (50 mg) in toluene (1.0 mL) and H2O

(10 lL) at 65 �C for 3 days with stirring, as shown in

Scheme 1. After the reaction, the immobilized lipase

CA was removed by filtration, and the solvent was

evaporated under reduced pressure. Purification was

carried out by reprecipitation using methanol (0.2 mL,

good solvent) and ethyl acetate (1.0 mL, poor solvent)

to obtain the corresponding quaternary ammonium

alcohol (3HPr) in 92% yield. The molecular structure

of the degradation products was analyzed by 1H NMR

spectroscopy.

The regeneration of G12Pr was carried out using the

degradation products and diphenyl carbonate. That is, a

mixture of 3HPr (20.5 mg), 1-dodecyl = phenyl = car-

bonate (50.0 mg) and immobilized lipase CA (5.0 mg) in

dry acetonitrile (1.0 mL) was stirred at 40 �C for 4 days.

After the reaction, the immobilized lipase CA was

removed by filtration and the solvent was evaporated

under reduced pressure to obtain the crude product.

Purification was carried out by recrystallization from

ethyl acetate (1.0 mL) to obtain the G12Pr in 35% yield.

The molecular structure was confirmed by 1H NMR

spectroscopy.

Scheme 4 Synthesis of G12Pr-derived 3HPr

Table 4 Synthesis and analytical data of S12X

Cationics Yield mp 1H NMR (300 MHz, CDCl3) C% H% N%

(%) (�C) d (ppm) Found Calcd. Found Calcd. Found Calcd.

S12Pr 85 115–117 0.88 (3H, t, J = 6.6 Hz), 1.19–1.42 (18H,

m), 1.67 (2H, tt, J = 6.9, 6.9 Hz),

2.21–2.33 (2H, m), 3.53 (9H, s),

3.73–3.84 (2H, m), 4.14 (2H, t,

J = 6.9 Hz), 4.30 (2H, t, J = 6.0) Hz)

49.76 49.89 8.68 8.81 3.07 3.06

S12iPr 87 141–142 0.88 (3H, t, J = 6.6 Hz), 1.18–1.43 (18H,

m), 1.48 (3H, d, J = 6.9 Hz), 1.67 (2H,

tt, J = 6.9, 6.9 Hz), 3.54 (9H, s), 3.59

(1H, dd, J = 9.9, 14.1 Hz), 4.09–4.25

(2H, m), 4.57 (1H, d, J = 14.1 Hz),

5.25–5.37 (1H, m)

49.73 49.89 8.71 8.81 2.93 3.06

392 J Surfact Deterg (2010) 13:387–398

123

Antimicrobial Activities

The antimicrobial activities of the surfactants were

evaluated by the agar dilution method [28]. Gram-posi-

tive bacterial strains (Staphylococcus aureus KB210,

Bacillus subtilis KB211, and Micrococcus luteus KB212),

gram-negative bacterial strains (Escherichia coli KB213,

Salmonella typhimurium KB20, and Pseudomonas aeru-

ginosa KB115), six fungal strains (Candida albicans

KF1, Saccharomyces cerevisiae KF25, Trichophyton

mentagrophytes KF213, Microsporum gypseum KF64,

Penicillium chrysogenum KF270, and Aspergillus niger

KF103) were used. Nutrient agar and Sabouraud dextrose

agar were used for the bacteria and fungi, respectively.

The antimicrobial activity was expressed as the minimum

inhibitory concentration (MIC).

Results and Discussion

Synthesis of Gemini-Type Cationics Containing

Carbonate Linkages

The CnX was prepared in a one-pot two-step successive

reaction according to our previous report [23]. That is,

CnX was first prepared by the reaction of diphenyl car-

bonate and 1-alkanol in the presence of Et3N followed by

the reaction of N,N-dimethylaminoalcohol in a one-pot

two-step reaction procedure, as shown in Scheme 1.

Simultaneous quaternarization and gemini formation

readily occurred at 80 �C for 1 day by the reaction with

CnX and 1,3-diiodopropane in dry acetonitrile to produce

GnX containing a carbonate linkage in the hydrophobic

moiety in 68–86% yield. The yield of G12Pr was 66%

when the concentration of 1,3-diiodopropane was

0.2 mol L-1. On the other hand, its yield was 85% when

the concentration of 1,3-diiodopropane was 0.1 mol L-1.

These results implied that the solubility of G12Pr was

relatively low in acetonitrile. mG12Pr containing carbon-

ate linkages both in hydrophobic and linker moieties was

prepared at 80 �C for 3 days by the reaction with CnX and

a,x-diiodide containing a carbonate linkage (3) in 68–74%

yield. In a 1-day reaction, the yield of 2G12Pr was only

20%. The maximum yield was 74% when the reaction time

was 3 days. This could be due to the lower reactivity of the

larger molecular size of di(iodoalkyl) carbonate. The

gemini-type cationics containing carbonate linkage only in

the linker moiety was prepared using dry ethyl acetate [24].

On the other hand, GnX and mG12Pr containing carbon-

ate linkages in the hydrophobic moiety were prepared in

dry acetonitrile due to the low solubility of mG12Pr in

ethyl acetate.

Hydrolytic Stability

In this study, a hydrolytic degradation test was carried out

by dissolving G12Pr and G12iPr in distilled water and

acetate and phosphate buffers (pH 4.0 and 7.0, respec-

tively) at 25 �C. It was found that both G12Pr and G12iPr

were stable in distilled water. Only a slight degradation

occurred after 20 days of incubation; the remaining car-

bonate was 98% for G12Pr and 97% for G12iPr. Figure 2

shows the time course of the hydrolytic degradation of

gemini-type cationics as measured by 1H NMR. G12iPr

was hydrolyzed faster at pH 7.0 in phosphate buffer com-

pared to pH 4.0 in acetate buffer. On the other hand,

G12Pr was practically stable at both pH 4.0 and 7.0. It is

reported that the hydrolysis of cationics having an ester

linkage in the vicinity of the polar hydrophilic groups was

influenced by the adjacent electron-withdrawing or elec-

tron-donating groups [19]. The G12Pr was hydrolytically

more stable in tested buffers when compared to G12iPr.

The higher hydrolyzability of G12iPr was due to the lower

electron density of the carbonyl carbon. Figure 3 shows the1H NMR spectra of G12Pr and G12iPr. Significant dif-

ferences in the chemical shift of the methylene protons

Fig. 2 Time course of

hydrolytic degradation of the

G12Pr and G12iPr in buffers at

25 �C. a G12Pr (open circles)

and G12iPr (filled circles) in

acetate buffer (pH 4.0).

b G12Pr (open circles) and

G12iPr (filled circles) in

phosphate buffer (pH 7.0).

Sample concentration: 5 g L-1

J Surfact Deterg (2010) 13:387–398 393

123

adjacent to the carbonate linkages were observed between

G12Pr [d 4.30 ppm (e in Fig. 3a)] and G12iPr [d5.21–5.38 ppm (e’ in Fig. 3b)]. These results implied that

the electron density of the carbonyl carbon of G12iPr was

lower than the electron density of the carbonyl carbon of

G12Pr. The distance between the carbonate linkage and

the quaternary ammonium group of G12iPr is shorter than

that of G12Pr. Therefore, the carbonyl carbon of G12iPr

was affected more by the positive charge of the quaternary

ammonium group than that of G12Pr.

Surfactant Properties of Gemini-Type Cationics

Containing Carbonate Linkages in Aqueous Solution

Figure 4 shows the plots of surface tension versus con-

centration of gemini-type cationics containing carbonate

linkages in aqueous solution. From these plots, the CMC,

the surface tension at the CMC values (cCMC), the effi-

ciency of adsorption at the surface (pC20) [pC20, the neg-

ative log of C20, the surfactant molar concentration

required to reduce surface tension by 20 mN m-1] [29,

Fig. 3 1H NMR spectra of

G12Pr (a) and G12iPr (b) in

CDCl3

394 J Surfact Deterg (2010) 13:387–398

123

30], and the Amin of gemini-type and single-type cationics

were determined and are listed in Table 5. It was found that

gemini-type cationics containing carbonate linkages

showed lower CMC values compared to the corresponding

single-type cationics. These low CMC values of gemini-

type surfactants were mainly caused by the simultaneous

migration of the two alkyl chains, rather than one, from the

aqueous phase to the micelle [31–33]. No significant dif-

ferences in the CMC values of the tested gemini-type

cationics containing both the carbonate linkages and

n-dodecyl groups were observed according to the linker

structure. It was also found that G12X showed lower cCMC

values when compared to the corresponding single-type

S12X. The cCMC of 3G12Pr was slightly higher than that

of 2G12Pr. This is due to the difference in the linker length

between the quaternary ammonium groups. That is, the

2G12Pr having an ethoxycarbonyloxyethyl-type linker

(m = 2 in Fig. 1) showed a lower cCMC value when com-

pared to the corresponding 3G12Pr having a propoxy-

carbonyloxypropyl-type linker (m = 3). The lower cCMC of

2G12Pr was due to the higher intra- and intermolecular

hydrophobic interactions between the two hydrophobic

alkyl chains of the gemini-type surfactant. This is also

supported by the results that the Amin of the 2G12Pr was

smaller than that of 3G12Pr. Furthermore, the pC20 values

of the gemini-type cationics containing carbonate linkages

were higher than those of the corresponding single-type

cationics. That is, the gemini-type cationics containing

carbonate linkages adsorb more efficiently at the surface

than the corresponding single-type cationics.

Biodegradabilities

The quick and complete biodegradation of surfactants after

use is needed in terms of the establishment of green and

sustainable chemistry, because water-soluble household

detergents are generally difficult to recover or reuse. The

biodegradation of the synthetic gemini-type cationics

containing carbonate linkages first occurs at enzymatically

hydrolyzable carbonate linkages by environmental

microbes with the evolution of carbon dioxide to form low-

molecular-weight fragments. Further microbial assimilation

of primary degradation products then follows [22]. If such

degradation products are biodegradable, the parent surfac-

tants can be regarded as biodegradable.

Figure 5 shows the BOD-biodegradation (BOD/

ThOD 9 100) of gemini-type cationics and the G12Pr-

derived degradation products [quaternary ammonium

alcohol: 3HPr and 1-dodecanol (DD) shown in Scheme 1].

The single-type cationics containing carbonate linkages,

S12Pr, was biodegraded by the activated sludge, and its

BOD-biodegradability exceeded 60% after a 45-day incu-

bation. The conventional gemini-type cationics, G12,

which had no hydrolytically cleavable moiety, showed no

biodegradation by activated sludge. On the other hand, the

G12X containing carbonate linkages showed higher bio-

degradability when compared to the conventional G12. It

was found that the biodegradability was improved by the

introduction of carbonate linkages into the hydrophobic

moiety of the gemini-type cationics. However, the biode-

gradability of G12Pr was relatively low at around 25%

Fig. 4 Surface tension versus concentration of gemini-type cationics containing carbonate linkages in aqueous solution at 25 �C. a G8Pr (opencircles); G10Pr (filled circles); G12Pr (open squares). b 2G12Pr (open circles); 3G12Pr (filled circles). c G12iPr (open circles)

Table 5 Surfactant properties of gemini-type and single-type

cationics in aqueous solution at 25 �C

Cationics CMC (mM) cCMC

(mN m-1)

pC20 102 Amin

(nm2)

G8Pr 0.948 32.2 3.6 81.2

G10Pr 0.146 30.4 4.6 99.6

G12Pr 0.0578 30.8 5.2 118

2G12Pr 0.0401 33.9 5.1 107

3G12Pr 0.0571 36.7 5.2 162

G12iPr 0.0254 33.2 5.5 127

G12 0.165 30.7 4.3 66.7

S12Pr 0.431 32.8 4.0 60.1

S12iPr 1.29 34.7 3.6 73.5

J Surfact Deterg (2010) 13:387–398 395

123

after 28 days of incubation. This is due to the relatively

low biodegradability of 3HPr as the primary biodegrada-

tion intermediate, i.e., 10% BOD-biodegradation after

28 days, as shown in Fig. 5. On the other hand, 1-dodec-

anol as the degradation intermediate was readily biode-

graded by activated sludge, and its BOD-biodegradability

exceeded 60% after 28 days. Based on these results, the

low biodegradability of G12Pr was due to the low biode-

gradability of the degradation intermediates having two

ammonium groups, 3HPr.

The biodegradability of gemini-type cationics containing

carbonate linkages was influenced by the linker structure.

Though the 2G12Pr was quickly biodegraded, the 3G12Pr

showed relatively low biodegradability. This is due to the

difference in the primary degradation products. In order to

compare the hydrolytic degradability of 2G12Pr and

3G12Pr, an accelerated hydrolytic degradation test was

carried out by dissolving the gemini-type cationics at

5 g L-1 in distilled water and stirring at a higher temperature

of 60 �C. The hydrolytic degradation of 2G12Pr was ana-

lyzed by comparing the 1H NMR profiles of the reactants

before and after the degradation, and the results are shown in

Fig. 6a. Significant differences in the hydrolytic degradation

were observed depending on whether the carbonate linkage

was in the linker moiety or the hydrophobic moiety of the

2G12Pr. The carbonate linkage in the linker moiety gradu-

ally hydrolyzed in water, and only 18% remained after 9 h of

reaction. On the other hand, 97% of the carbonate linkage in

the hydrophobic moiety remained after 9 h. These results

indicated that the carbonate linkage in the hydrophobic

moiety was more stable against hydrolysis than the carbonate

linkage in the linker moiety. Therefore, 2G12Pr was readily

hydrolyzed at the carbonate linkage in the linker moiety to

produce the corresponding quaternary ammonium alcohols

having a similar molecular structure to the single-type

S12Pr, which exhibited good biodegradability.

Next, 1H NMR profiles before and after the hydrolysis

of 3G12Pr were analyzed. The results are shown in

Fig. 6b. The carbonate linkage in the linker moiety was

stable in water, and 95% of the carbonate linkage remained

after 9 h at 60 �C. Also, 96% of the carbonate linkage in

the hydrophobic moiety remained after the hydrolysis. It

was found that the carbonate linkage in the linker moiety of

3G12Pr was hydrolytically more stable than the carbonate

linkage in the linker moiety of 2G12Pr. Based on these

results, 2G12Pr was readily cleaved at the carbonate

linkage in the linker moiety, indicating a higher degree of

BOD-biodegradability than 3G12Pr.

Enzymatic Degradation and Reproduction for Chemical

Recycling

In terms of green and sustainable chemistry, even water-

soluble surfactants should be chemically recycled, partic-

ularly in industrial fields. Gemini-type cationics containing

carbonate linkages were hydrolyzed by lipase and accom-

panied by carbon dioxide evolution to produce the corre-

sponding alcohol and quaternary ammonium alkanol,

which could be converted into the initial gemini-type

Fig. 5 BOD-biodegradability of gemini-type and single-type cation-

ics containing carbonate linkages and G12Pr-derived degradation

products, 3HPr and DD, at 25 �C for 28 days (*45 days). Activated

sludge: 30 ppm; sample concentration: ca. 40 ppm

Fig. 6 Time course of

hydrolytic degradation of

mG12Pr in distilled water at

60 �C. a Remaining carbonate

in the hydrophobic moiety

(open circles) and linker moiety

(filled circles) of 2G12Pr.

b Remaining carbonate in the

hydrophobic moiety (opencircles) and linker moiety (filledcircles) of 3G12Pr. Sample

concentration: 5 g L-1

396 J Surfact Deterg (2010) 13:387–398

123

cationics by the reaction with diphenyl carbonate. A lipase-

catalyzed chemical recycling procedure may become a

green method because lipase is a renewable catalyst with

high catalytic activities.

The enzymatic degradation of G12X was carried out in

toluene containing a small amount of water using immo-

bilized lipase CA. The G12Pr was degraded at the car-

bonate linkage into the quaternary ammonium alcohol

(3HPr) and 1-dodecanol, as shown in Scheme 1. The

G12Pr was regenerated by the reaction of 3HPr and

1-dodecyl = phenyl = carbonate, which was prepared by

the Et3N-catalyzed reaction of 1-dodecanol and diphenyl

carbonate (78% yield). That is, a mixture of 3HPr,

1-dodecyl = phenyl = carbonate, and immobilized lipase

CA was stirred in dry acetonitrile to obtain G12Pr. Based

on these results, G12Pr showed chemical recyclability

using lipase CA. On the other hand, the G12iPr was not

quickly degraded by lipase under similar conditions. The

lower enzymatic degradability of G12iPr was due to the

steric hindrance of the side methyl group.

Antimicrobial Activities

The gemini-type cationics were screened for their antimi-

crobial activities toward gram-positive and gram-negative

bacterial strains and fungal strains based on the determi-

nation of their MICs [28]. These results are shown in

Table 6. The MIC value shows the lowest concentration of

a surfactant at which the tested microorganisms do not

show visible growth. It is reported that cationic surfactants

having multi-polar groups showed higher antimicrobial

activities compared to the corresponding single-type cat-

ionics because of the much higher charge density carried

by multi-polar cationics [34, 35]. However, G12X showed

lower antimicrobial activities when compared to the cor-

responding single-type S12X. The low antimicrobial

activities of G12Pr could be due to the ready cleavability

of the carbonate linkages of G12Pr by microbes forming

surface-inactive compounds, 3HPr, as shown in Scheme 1.

The 2G12Pr containing carbonate linkages both in the

hydrophobic and linker moieties showed higher antimi-

crobial activities than the 3G12Pr. As discussed above,

2G12Pr was readily hydrolyzed at the carbonate linkage in

the linker moiety to produce the corresponding quaternary

ammonium alcohols having a similar molecular structure to

the single-type S12Pr, which exhibited strong antimicro-

bial activities. On the other hand, 3G12Pr could be cleaved

at the carbonate linkages in both the hydrophobic and

linker moieties to produce the antimicrobially inactive

alkyl chain-free fragments. Therefore, the antimicrobial

activities of 3G12Pr were lower than those of 2G12Pr.

Acknowledgments Immobilized lipase from Candida antarctica(lipase CA, Novozym 435) was kindly supplied by Novozymes Japan

Ltd. (Chiba, Japan). This work was supported by a Grant-in-Aid for

JSPS Fellows 21�4882 from the Ministry of Education, Culture,

Sports, Science and Technology (MEXT), Japan. This work was also

supported by the High-Tech Research Center Project for Private

Universities, matching the fund subsidy from the MEXT, 2006–2011.

References

1. Okada Y, Banno T, Toshima K, Matsumura S (2009) Synthesis

and properties of polycarboxylate-type green surfactants with

S- or N-linkages. J Oleo Sci 58:519–528

2. Moran MC, Pinazo A, Perez L, Clapes P, Angelet M, Garcıa MT,

Vinardell MP, Infante MR (2004) ‘‘Green’’ amino acid-based

surfactants. Green Chem 6:233–240

Table 6 Antimicrobial activities of gemini-type and single-type cationics containing an n-dodecyl group and G12Pr-derived 3HPr

Strain MIC (lg/mL)

G12Pr 2G12Pr 3G12Pr G12iPr G12 S12Pr S12iPr 3HPr

S. aureus 200 5 100 100 25 2.5 2.5 [400

B. subtilis 200 10 50 100 10 2.5 5 [400

M. luteus 400 25 100 100 25 5 2.5 [400

E. coli 400 200 200 200 100 10 10 [400

S. typhimurium [400 400 [200 [400 100 200 200 [400

P. aeruginosa 400 200 [200 [400 100 100 400 [400

C. albicans [400 400 [200 [400 [400 [400 400 [400

S. cerevisiae [400 400 [200 [400 [400 400 400 [400

T. mentagrophytes [400 100 [200 200 100 50 400 100

M. gypseum 400 25 100 400 50 10 5 200

P. chrysogenum [400 400 [200 [400 400 200 100 [400

A. niger [400 [400 [200 [400 400 [400 [400 [400

J Surfact Deterg (2010) 13:387–398 397

123

3. Goursaud F, Berchel M, Guilbot J, Legros N, Lemiegre L,

Marcilloux J, Plusquellec D, Benvegnu T (2008) Glycine betaine

as a renewable raw material to ‘‘greener’’ new cationic surfac-

tants. Green Chem 10:310–320

4. Bunton CA, Robinson LB, Schaak J, Stam MF (1971) Catalysis

of nucleophilic substitutions by micelles of dicationic detergents.

J Org Chem 36:2346–2350

5. Menger FM, Littau CA (1991) Gemini-surfactants: synthesis and

properties. J Am Chem Soc 113:1451–1452

6. Menger FM, Littau CA (1993) Gemini surfactants: a new class of

self-assembling molecules. J Am Chem Soc 115:10083–10090

7. Rosen MJ, Tracy DJ (1998) Gemini surfactants. J Surfact Deterg

1:547–554

8. Menger FM, Keiper JS (2000) Gemini surfactants. Angew Chem

Int Ed Engl 39:1906–1920

9. Zana R, Talmon Y (1993) Dependence of aggregate morphology

on structure of dimeric surfactants. Nature 362:228–230

10. Devınsky F, Masarova L, Lacko I (1985) Surface activity and

micelle formation of some new bisquaternary ammonium salts.

J Colloid Interface Sci 105:235–239

11. Devınsky F, Lacko I, Bittererova F, Tomeckova L (1986) Rela-

tionship between structure, surface activity, and micelle formation

of some new bisquaternary isosteres of 1,5-pentanediammonium

dibromides. J Colloid Interface Sci 114:314–322

12. Wagenaar A, Engberts JBFN (2007) Synthesis of nonionic

reduced-sugar based bola amphiphiles and gemini surfactants

with an a,x-diamino-(oxa)alkyl spacer. Tetrahedron

63:10622–10629

13. Klijn JE, Stuart MCA, Scarzello M, Wagenaar A, Engberts JBFN

(2007) pH-Dependent phase behavior of carbohydrate-based

gemini surfactants. The effects of carbohydrate stereochemistry,

head group hydrophilicity, and nature of the spacer. J Phys Chem

B 111:5204–5211

14. Klijn JE, Stuart MCA, Scarzello M, Wagenaar A, Engberts JBFN

(2006) pH-Dependent phase behavior of carbohydrate-based

gemini surfactants. Effect of the length of the hydrophobic

spacer. J Phys Chem B 110:21694–21700

15. Perez L, Torres JL, Manresa A, Solans C, Infante MR (1996)

Synthesis, aggregation, and biological properties of a new class of

gemini cationic amphiphilic compounds from arginine, bis(args).

Langmuir 12:5296–5301

16. Tsatsaroni E, Pegiadou-Koemtjopoulou S, Demertzis G (1987)

Synthesis and properties of new cationic surfactants. 2. Odd

homologous members. J Am Oil Chem Soc 64:1444–1447

17. Tatsumi T, Zhang W, Nakatsuji Y, Miyake K, Matsushima K,

Tanaka M, Furuta T, Ikeda I (2001) Preparation, surface-active

properties, and antimicrobial activities of bis(alkylammonium)

dichlorides having a butenylene or a butynylene spacer. J Surfact

Deterg 4:271–277

18. Fernandez P, Valls M, Bayona JM, Albalges J (1991) Occurrence

of cationic surfactants and related products in urban coastal

environments. Environ Sci Technol 25:547–550

19. Tehrani-Bagha AR, Oskarsson H, van Ginkel CG, Holmberg K

(2007) Cationic ester-containing gemini surfactants: chemical

hydrolysis and biodegradation. J Colloid Interface Sci

312:444–452

20. Tatsumi T, Zhang W, Kida T, Nakatsuji Y, Ono D, Takeda T,

Ikeda I (2000) Novel hydrolyzable and biodegradable cationic

gemini surfactants: 1,3-bis[(acyloxyalkyl)-dimethylammonio]-

2-hydroxypropane dichloride. J Surfact Deterg 3:167–172

21. Tatsumi T, Zhang W, Kida T, Nakatsuji Y, Ono D, Takeda T,

Ikeda I (2001) Novel hydrolyzable and biodegradable cationic

gemini surfactants: bis(ester-ammonium) dichloride having a

butenylene or a butynylene spacer. J Surfact Deterg 4:279–285

22. Stjerndahl M, Holmberg K (2005) Hydrolyzable nonionic sur-

factants: stability and physicochemical properties of surfactants

containing carbonate, ester, and amide bonds. J Colloid Interface

Sci 291:570–576

23. Banno T, Toshima K, Kawada K, Matsumura S (2007) Synthesis

and properties of biodegradable and chemically recyclable cationic

surfactants containing carbonate linkages. J Oleo Sci 56:493–499

24. Banno T, Toshima K, Kawada K, Matsumura S (2009) Synthesis

and properties of gemini-type cationic surfactants containing

carbonate linkages in the linker moiety directed toward green and

sustainable chemistry. J Surfact Deterg 12:249–259

25. Alami E, Beinert G, Marie P, Zana R (1993) Alkanediyl-a,

x-bis(dimethylalkyl-ammonium bromide) surfactants. 3. Behav-

ior at the air–water interface. Langmuir 9:1465–1467

26. Esumi K, Taguma K, Koide Y (1996) Aqueous properties of mul-

tichain quaternary cationic surfactants. Langmuir 12:4039–4041

27. Organization for Economic Cooperation and Development

(OECD) (1981) OECD guidelines for testing of chemicals, 301C,

modified MITI test. OECD, Paris

28. Bistline RG Jr, Maurer EW, Smith FD, Linfield WM (1980) Fatty

acid amides and anilides, syntheses and antimicrobial properties.

J Am Oil Chem Soc 57:98–103

29. Zhu YP, Ishihara K, Masuyama A, Nakatsuji Y, Okahara M

(1993) Preparation and properties of double-chain bis(quaternary

ammonium) compounds. Yukagaku 42:161–167

30. Kim TS, Kida T, Nakatsuji Y, Hirao T, Ikeda I (1996) Surface-active

properties of novel cationic surfactants with two alkyl chains and

two ammonio groups. J Am Oil Chem Soc 73:907–911

31. Zana R (1996) Critical micellization concentration of surfactants

in aqueous solution and free energy of micellization. Langmuir

12:1208–1211

32. Zana R (2002) Dimeric (gemini) surfactants: effect of the spacer

group on the association behavior in aqueous solution. J Colloid

Interface Sci 248:203–220

33. Zana R (2002) Dimeric and oligomeric surfactants. Behavior at

interfaces and in aqueous solution: a review. Adv Colloid Inter-

face Sci 97:205–253

34. Willemen HM, de Smet LCPM, Koudijs A, Stuart MCA, Heik-

amp-de Jong IGAM, Marcelis ATM, Sudholter EJR (2002)

Micelle formation and antimicrobial activity of cholic acid

derivatives with three permanent ionic head groups. Angew

Chem Int Ed Engl 41:4275–4277

35. Haldar J, Kondaiah P, Bhattacharya S (2005) Synthesis and

antibacterial properties of novel hydrolyzable cationic amphi-

philes. Incorporation of multiple head groups leads to impressive

antibacterial activity. J Med Chem 48:3823–3831

Author Biographies

Taisuke Banno is a Ph.D. student at Keio University, Japan. His main

interests are the synthesis, physicochemical properties, biodegrada-

tion, and chemical recycling of green gemini-type surfactants.

Kazuo Kawada received his Ph.D. in the synthesis and physico-

chemical properties and microbial properties of nonionic surfactants

from Keio University. He is currently an assistant professor of the

Department of Chemistry, School of Science, Kitasato University. His

main research interests are the synthesis and evaluation of antimi-

crobial agents and surfactants.

Shuichi Matsumura earned a Ph.D. and is currently a professor of

the Department of Applied Chemistry, Keio University. His research

program focuses on the development of novel enzyme-catalyzed

polymerization for the establishment of green chemistry, sustainable

chemical recycling of green and bio-based plastics using an enzyme,

and new biodegradable surfactants and detergent builders.

398 J Surfact Deterg (2010) 13:387–398

123

本文献由“学霸图书馆-文献云下载”收集自网络，仅供学习交流使用。

学霸图书馆（www.xuebalib.com）是一个“整合众多图书馆数据库资源，

提供一站式文献检索和下载服务”的24 小时在线不限IP

图书馆。

图书馆致力于便利、促进学习与科研，提供最强文献下载服务。

图书馆导航：

图书馆首页 文献云下载 图书馆入口 外文数据库大全 疑难文献辅助工具