Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Patent
1988-11-03
1991-04-16
Griffin, Ronald W.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
2604108, C07H 1306, C07H 1512, C07C 69716, B01F 1700
Patent
active
050083830
DESCRIPTION:
BRIEF SUMMARY
This invention relates to novel surface active compositions and to a process for their preparation.
It is already known that certain bacteria when cultivated under suitable conditions will produce useful surface active substances. Some of the most active of these bio-surfactants are exemplified by trehalose 6,6'-corynemycolate (which has formula I shown below), and are glycolipids having a hydrophilic moiety which is a sugar, which is esterified by hydrophobic components namely one or more fatty acids, the latter being of a particular type, that is, acids with double alkyl chains, constituted by the attachment of a second long alkyl chain at the 2-position of a long alkyl fatty acid; and either or both alkyl chains may carry other substituents or functional groups such as hydroxyl groups or centres of unsaturation.
Bio-surfactants of this type are known to show many desirable properties, and have been advocated as emulsification and wetting agents with potentially wide applications (as for instance by D. Gutnick, World Biotechnology Report (Biotech 84 U.S.A.), 1984, Volume 2, pp 645-652). Typically such bio-surfactants will lower the surface tension of aqueous salt solutions to ca. 30 dynes/cm at an air interface, or ca. 1-8 dynes/cm at an oil interface, and show critical micelle concentrations as low as 0.02 to 0.0002% w/w. However their production on an industrial scale by means of microbial cultures (as for instance might follow from studies such as described by Rapp, Bock, Wray & Wagner, J. Gen. Microbiol. 115, 491(1979)) is not likely to be very practical or economic because of generally low yields and technical difficulties in the fermentation and recovery processes (Parkinson, Biotechnology Advances 3, 65-83 (1985)). ##STR1##
Equally there exist several well-known industrial routes whereby surface-active sugar esters may be commercially produced but, when using readily-available sugars and readily-available fatty acid derivatives, by such routes it has not hitherto been possible to produce sugar ester similar to (I), that is, with double alkyl chains as already described.
Specific chemical syntheses of (I) or related substances have been described, as for instance by Bottle and Jenkins, J. Chem. Soc. Chem. Commun. 1984, p385, or earlier workers, but they comprise several stages, are generally laborious, and are not such as to offer any commercially practicable route for the economic production of such substances.
An object of the present invention is to provide a process whereby novel useful surface active compositions comprising substances having double alkyl chains can be prepared in a simple and convenient manner.
According to the present invention there is provided a process for the preparation of a surface-active substance having the general formula ##STR2## wherein; each of R.sub.1 and R.sub.2, which may be the same or different, is an alkyl chain having from 6 to 20 carbon atoms; ##STR3## said process comprising reacting a compound of the general formula general formula III or IV; ##STR4## wherein R.sub.1 and R.sub.2 are as stated above, so that the group YH is acylated by the diketene, the acylation reaction being carried out in the presence of a non-acylable nitrogenous base as proton acceptor catalyst and in a polar aprotic solvent medium.
The non-acylable nitrogenous base may be a tertiary amine or a pyridine or a tertiary amino pyridine derivative.
Preferably, the said alkyl chains R.sub.1 and R.sub.2 are unbranched and contain no more than three double bonds.
Preferably, the said alkyl chains R.sub.1 and R.sub.2 are at least substantially unbranched and contain from 0 to 3 double bonds.
It is to be understood that the process of the invention may result in a composition which comprises a single surface-active substance, and the or each such substance may have one or a plurality of acylated groups.
In performing the process of the invention diketenes [ketene dimers, formulae (III), (IV)] are used which can be readily and efficiently obtained from common fatty acids (as for instance descr
REFERENCES:
patent: 3214461 (1965-10-01), Elam et al.
Bu'lock John D.
Donnelly Michael J.
Sutherland James K.
31 Research Exploitation Limited
Griffin Ronald W.
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