Effects of Molecular Association on the Rates of Hydrolysis of Long-Chain Alkyl Betainates (Alkoxycarbonyl-N,N,N-Trialkylmethanaminium Halides).

Thompson, Richard A.; Allenmark, Stig; Larsen, Sine; Teuber, Lene; Lucanska, Brigitta; Krätsmar-Smogrovic, Juraj; Valent, Aladár; Alminger, Tomas; Erickson, Magnus; Grundevik, Inger; Hagin, Inger; Hoffman, Kurt-Jürgen; Johansson, Svante; Larsson, Sam; Löfberg, Ingalil; Ohlson, Kristina; Persson, Björn; Skånberg, Inger; Tekenbergs-Hjelte, Lija

doi:10.3891/acta.chem.scand.43-0690

Cited by 29 publications

(34 citation statements)

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“…The errors of the fit were estimated using Monte Carlo simulations but were found to be negligible, and for clarity, error bars are not included in the graphs. The volume fraction, φ, of surfactant was calculated using ρ D 2 O = 1.11 g/cm 3 and ρ surf = 0.989 g/cm 3 . The latter was calculated from the compilation of group volumes given in Reference 16.…”

Section: [D]/([d]+[h])mentioning

confidence: 99%

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Nuclear magnetic resonance studies on hydrolysis kinetics and micellar growth in solutions of surface‐active betaine esters

Lundberg

Holmberg

2004

J Surfact & Detergents

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A series of surface-active betaine esters of medium-to long-chain alcohols has been synthesized. The hydrophobic parts used were decyl, dodecyl, tetradecyl, and oleyl chains. Ethyl betainate was prepared as a non-surface-active reference compound. The surfactants were characterized by critical micellization concentration (CMC), and base-catalyzed hydrolysis was studied by using 1 H nuclear magnetic resonance (NMR). Micellar catalysis was shown to have a strong influence on the hydrolysis. This means that the hydrolysis rates are concentration dependent. For dodecyl betainate, the effect of the degradation products (dodecanol and betaine) on the micellar shape was investigated by NMR diffusion experiments. The degradation products were shown to induce micellar growth.There is considerable current interest in cleavable surfactants, i.e., surfactants with a built-in weak linkage (1,2). Environmental concerns are the main driving force behind the development of such surfactants, but technical considerations are also important. For instance, a surfactant may be needed at one stage of a process but unwanted at a later stage. A controlled degradation, caused by a change of pH, ultraviolet (UV) irradiation, ozone treatment, etc., can then be advantageous.Most cleavable surfactants contain a hydrolyzable bond, and the cleavage may be either acid-or base-catalyzed. Surface-active acetals, ketals, and ortho esters are examples of surfactants susceptible to acid hydrolysis. Surface-active esters are by far the most common type of surfactant that breaks down readily under alkaline conditions.The rate of alkaline hydrolysis of esters is influenced by the presence of electron-attracting or -withdrawing groups in the vicinity of the ester bond. A cationic charge adjacent to the carbonyl carbon of the ester bond is known to be particularly effective in increasing the rate of base-catalyzed hydrolysis. Betaine esters of long-chain alcohols are one such type of ester, and such surfactants have been shown to break down readily under only slightly alkaline conditions (3).It is possible to design betaine esters that degrade into naturally occurring substances. Both chemical and enzymatic hydrolysis yields the amino acid betaine and the starting alcohol, two products that can be regarded as environmentally compatible and possibly even edible. Thus, betaine ester surfactants are interesting candidates for applications in systems such as cosmetics, food, and feed.The aim of the present paper is to present in some detail the breakdown kinetics of a series of surface-active betaine esters and the effect of the degradation products on the micellar structure. In previous work on betaine ester surfactants, the products were modified with a p-nitrophenyl group, and UV was used to monitor the degradation (3). A drawback with this procedure is that the derivatization will affect the physicochemical properties of the surfactants. With the nuclear magnetic resonance (NMR) techniques employed in this work, it is possible to study the unmodified est...

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Section: [D]/([d]+[h])mentioning

confidence: 99%

“…In previous work on betaine ester surfactants, the products were modified with a p-nitrophenyl group, and UV was used to monitor the degradation (3). A drawback with this procedure is that the derivatization will affect the physicochemical properties of the surfactants.…”

mentioning

confidence: 99%

Nuclear magnetic resonance studies on hydrolysis kinetics and micellar growth in solutions of surface‐active betaine esters

Lundberg

Holmberg

2004

J Surfact & Detergents

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“…These compounds were shown to have good microbicidal activity and are degraded to betaine and long-chain alcohols. The rate of hydrolysis of the compounds is pH dependent and was found to be highly influenced by the amphiphilic nature of the substances (22,23).…”

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Long-chain alkanoylcholines, a new category of soft antimicrobial agents that are enzymatically degradable

Ahlström

Chelminska-Bertilsson

Thompson

et al. 1995

Antimicrob Agents Chemother

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A new category of amphiphilic hydrolyzable quaternary ammonium compounds with rapid and high levels of antimicrobial activity was studied. The compounds, alkanoylcholines with hydrocarbon chains of 10 to 14 carbon atoms, are hydrolyzed by butyrylcholine esterase, which is present in human serum and mucosal membranes. The hydrolysis products are common components of human metabolism. Alkanoylcholines were tested and found to be active against gram-negative and gram-positive bacteria as well as yeasts. The microbicidal activities of the alkanoylcholines were comparable to the activities of the stable quaternary ammonium compounds of corresponding chain length and increased with an increasing number of carbon atoms. The compounds were also found to be hydrolyzed by enzymes present in certain microorganisms. The degradation was achieved after reaching the microbicidal effect.

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“…5), indicating no reduction of hydrolysis at this pH. This might be due to an effect on the microenvironment of the bacteria (Thompson & Allenmark, 1989) since at lower pH charge interaction would be weaker as the negative charge of the bacterial surface is reduced. These experiments were facilitated by the strong binding of B14 and tetradecanol to the bacteria and the release of betaine which was confirmed after separation of ester, betaine and tetradecanol by HPLC with on-line detection (Fig.…”

Section: Discussionmentioning

confidence: 99%

Hydrolysis of the soft amphiphilic antimicrobial agent tetradecyl betainate is retarded after binding to and killing Salmonella typhimurium

Ahlström

Edebo

1998

Microbiology

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Hydrolysis of tetradecyl betainate (B14), a fast-acting microbicidal amphiphilic quaternary ammonium compound (QAC) being an ester of betaine and tetradecanol, occurred after binding to Salmonella typhimurium, resulting in an -Sweden release of the water-soluble betaine portion and retention of the lipophilic tetradecanol. The rate of the hydrolysis was significant but retarded in comparison to B14 in solution. As in free solution, the hydrolysis of substance bound to S. typhimurium was increased in an alkaline environment and by heat. A t pH 6.0 and 20 OC the hydrolysis of bound ester was about 10% after 180 min, whereas at pH 9.0 and 50 OC it was about 50% after 60 min. These results are consistent with a model where amphiphilic QACs are inserted into the bacterial outer membrane (OM) with the quaternary ammonium head group facing outwards and the lipophilic portion, including the ester bond, being in the membrane lipid environment enough for retarding the hydrolysis. However, calculation of the mean concentration of B14 in the bacteria at MBC, , (minimum bactericidal concentration required to kill 99% of cells) showed a 7000-8000 times greater concentration than in the medium. A t this concentration, when most B14 is considered to be bound to the OM, the available surface area for each molecule was only 2 A2. This is only 6 7 % of that required for close packing of the quaternary ammonium head group (30 A2), indicating that a three-dimensional, presumably continuous arrangement was formed. Since B14 is hydrolysed after its binding to bacteria with microbicidal effect, it may be used under conditions where stable QACs might be harmful to the close or the common environment.

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Effects of Molecular Association on the Rates of Hydrolysis of Long-Chain Alkyl Betainates (Alkoxycarbonyl-N,N,N-Trialkylmethanaminium Halides).

Cited by 29 publications

References 0 publications

Nuclear magnetic resonance studies on hydrolysis kinetics and micellar growth in solutions of surface‐active betaine esters

Nuclear magnetic resonance studies on hydrolysis kinetics and micellar growth in solutions of surface‐active betaine esters

Long-chain alkanoylcholines, a new category of soft antimicrobial agents that are enzymatically degradable

Hydrolysis of the soft amphiphilic antimicrobial agent tetradecyl betainate is retarded after binding to and killing Salmonella typhimurium

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