Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
2000-12-11
2003-03-18
Jones, Dwayne C. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S123100, C536S123120, C536S124000
Reexamination Certificate
active
06534647
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the use of alkylurethanes of fructans as surfactants, to compositions comprising alkylurethanes of fructans as surfactants, to novel alkylurethanes of fructans and to a process for their manufacture.
BACKGROUND AND PRIOR ART
Surface-active agents are widely used in compositions for household and industrial applications in which they act as detergents, foaming agents, foam stabilisers, wetting agents, emulsifiers and/or emulsion stabilisers. The oldest type of surface-active agents, mainly used as detergents, are the alkali soaps of fatty acids. Later on these soaps have been replaced to a large extent by much stronger synthetic surfactants. The elder generation of synthetic surfactants consisted mainly of alkylbenzenesulfonates (ABS). However, ABS caused considerable water pollution due to their poor biodegradability. At present, ABS have been largely replaced by linear alkylsulfonates (LAS) having ten or more carbon atoms in the alkyl chain, which present improved biodegradability compared to ABS surfactants.
To day, the search for alternative, more efficient and better biodegradable surfactants is still going on.
According to one approach, sugars such as glucose and sucrose (saccharose) have been used as starting material for the synthesis of non-ionic derivatives with surface-active properties.
V. Maunier et al. (Carbohydrate Research, 299, 49-57, (1997)) disclosed tensio-active properties of several 6-aminocarbonyl derivatives of methyl &agr;-D-glucopyranoside and D-glucose and compared them with the ones of the urethane named methyl 6-O-(N-heptylcarbamoyl)-&agr;-D-glucopyranoside.
T. Lesiak et al. (J. prakt. Chem., 322 (6), 877-883, (1980)) disclosed the use of 1-methyl-2,4-bis(isocyanato)benzene (commonly named tolylene-2,4-diisocyanate; in short 2,4-TDI) for the synthesis of urethanes of glucose and sucrose. First 2,4-TDI was reacted with various aliphatic long chain alcohols or terpene alcohols in a molar ratio 1:1. The reaction essentially occurred with the isocyanate group at position 4 and the urethane-mono-isocyanates obtained were then reacted with glucose, respectively sucrose, to yield the corresponding di-urethanes which presented moderate tensio-activity.
The synthesis of several sucrose N-n-alkylurethanes and their tensio-active properties have been disclosed inter alia by H. Bertsch et al. (J. prakt.
Chem., 11, 108 (1960)) and by W. Gerhardt (Abh. Dtsch. Akad. Wiss. Berlin, Kl. Chem., Geol. Biol., Vol 1966 (6), 24-32, (1967)). These derivatives present moderate to good tensio-active properties but only at rather high concentration. The urethanes have been prepared by reaction of sucrose with the selected n-alkylisocyanate (H. Bertsch et al. o.c.) and by transformation of sucrose with potassium cyanate and an n-alkyl-halogenide in dimethyl formamide (W. Gerhardt, o.c. ). However, sucrose n-alkylurethanes with longer alkyl chains, suffer from a moderate to poor solubility in water.
To improve the solubility in water of sugar n-alkylurethanes, corresponding n-alkylurethanes have been prepared from ethoxylated or propoxylated sugars. The synthesis and tensio-active properties of n-alkylurethanes derived from ethoxylated and propoxylated sucrose, respectively mannitol, have been disclosed by W. Gerhardt (o.c. and German Patent DE 1 518 696). Furthermore, 1-(n-alkyloxy)-ethylurethanes of sucrose have been synthesised and their tensio-active properties determined by T. Lesiak et al. (J. prakt. Chem., 319 (5), 727-731, (1977)).
Moreover, the preparation of miscellaneous urethanes derived from various carbohydrates have been disclosed.
European patent application EP 0 801 077 discloses n-alkyl C
1
-C
18
-urethanes of polysaccharides and ethoxylated polysaccharides, in particular of cellulose, and their use as thermoplastic material. Similarly, German patent application DE 43 38 152 A1 discloses n-alkylurethanes of starch and starch derivatives, such as acetylated starch, and their use as thermoplastic material.
European patent application EP 0 157 365 discloses various urethane derivatives of polysaccharides, inter alia inulin tri(phenylcarbamate), and discloses their use in the optical resolution of racemic mixtures.
I. Wolff et al. (J. Am. Chem. Soc., 76, 757 (1954)) disclosed to have prepared urethanes of starch, but later studies by E. Asveld et al. (Carbohydrate Polymers, 4, 103-110, (1984)) revealed that in the aqueous reaction conditions used by I. Wolff et al. no urethanes but only mixtures of the carbohydrate and the urea compounds have been obtained.
In view of the steadily increasing demand for surface-active agents for use in various applications, industry is continuously confronted with the need for alternative surface-active agents, which preferably present improved tensio-active properties and/or biodegradability.
OBJECT OF THE INVENTION
It is the object of the present invention to provide a solution to one or more of the above mentioned problems by the provision of alternative surface-active products which are readily soluble at low concentration in water at room temperature and which present good tensio-active properties and good biodegradability.
DESCRIPTION OF THE INVENTION
In their search for alternative and/or improved surfactants, the inventors have found that certain urethanes of fructans provide a solution to one or more of said problems.
In accordance with these findings, the present invention provides the use of certain alkylurethanes of fructans as surfactants, certain novel alkylurethanes of fructans suitable for use as surfactants, methods for preparing these compounds, and compositions comprising one or more of said alkylurethanes as surfactants and/or stabilisers.
By surface-active agent, surfactant or tensio-active agent are meant herein compounds that reduce the surface tension when dissolved in water or in an aqueous medium, or which reduce interfacial tension between two liquids, between a liquid and a solid or between a liquid and a gas. These terms are used herein interchangeably. The same applies to the terms designating said properties.
By the term alkylurethanes are commonly indicated a class of compounds resulting from the reaction of an alkylisocyanate with an alcoholic hydroxyl group bearing substrate, whereas the individual reaction products are named as N-alkylcarbamates, i.e. as esters of N-alkylcarbamic acid. However, the terms are often, also in this description, interchanged.
Fructans are well known naturally occurring polysaccharides embracing the carbohydrates levan and inulin.
Levans are D-fructans generally consisting of chains of polyfructose of which the fructose units are connected to each other mostly or exclusively by &bgr;(2-6) fructosyl-fructose linkages. Levans occur in nature in certain plant species (in this case they are also called phleins) and also originate from the activity of certain bacteria. Levans can be produced, according to conventional techniques, by extraction from certain plants, by fermentation techniques and by enzymatic in vitro synthesis. Levans usually occur as a polydisperse mixture of said polyfructose chains. The chains may be linear, but mostly they are branched.
Inulins are D-fructans too, generally consisting of chains of polyfructose but of which the fructose units are connected to each other mostly or exclusively by &bgr;(2-1) linkages. Inulin occurs in nature, in general, as a polydisperse mixture of polyfructose chains most of which are ending in one glucosyl unit. Inulin can be from bacterial origin, from vegetal origin or can be made in vitro by enzymatic synthesis starting from sucrose. Inulin produced by bacteria is more branched than inulin from plant origin and has commonly a higher molecular weight (ranging from about 2,000 up to about 20,000,000), whereas inulin from plant origin is generally composed of linear or slightly branched polyfructose chains or mixtures thereof with a molecular weight commonly ranging from about 600 to about 20,000.
Inulin can be represented, depending from the terminal carbohydrate unit, by
Booten Karl
Daenekindt Lucien
Laquiere Isabelle M.-A.
Stevens Christian Victor
Hayes & Soloway P.C.
Jones Dwayne C.
Tiense Suikerraffinaderij N.V.
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