Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
2003-07-11
2004-10-05
Wilson, James O. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S120000, C536S123100
Reexamination Certificate
active
06800741
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a series of polyglycoside derivatives that contain water-soluble groups introduced into the molecule by reaction with the hydroxyl groups present in the molecule. The preferred products have more than one water-soluble group per molecule and are made with mild reagents to avoid discoloration and mal odor.
Commercial alkyl polyglycosides generally have a low degree of polymerization of polysaccharide, in the molecule. This results in a molecule that is of limited water solubility. The present invention is aimed at functionalizing the hydrophobic alkyl polyglycoside, by including in the molecule polyoxyalkylene groups selected from polyoxyethylene, and polyoxypropylene both of which provide improved water solubility and improved surfactant properties.
BACKGROUND
Alkyl polyglycosides have been known for many years, having been first synthesized in the early 1900 by Emile Fischer. Despite this, the products were of little commercial interest until much later.
U.S. Pat. No. 4,393,203 issued Jul. 12, 1983 to Mao et al, incorporated herein by reference, disclose that long chain fatty alcohols can be removed from alkyl polysaccharide products in thin film evaporators to achieve fatty alcohol levels of less than about 2% without excessive discoloration of the alkyl polysaccharide. This allowed for a more cosmetically acceptable product to be developed that is more surface active. The presence of the free fatty alcohol in the mixture, allows for a more water-soluble product, by removing the water insoluble alcohol.
One of the most significant patents is U.S. Pat. No. 5,003,057 issued Mar. 26, 1991 to McCurry et al incorporated herein by reference, provides for a process for preparing glycosides from a source of saccharide moiety and an alcohol in the presence of a hydrophobic acid catalyst is provided. An example of such a catalyst is dinonylnaphthalenemonosulfonic acid. The use of such catalysts provides a number of process advantages, which includes the reduced production of polar by-products. Preferred glycosides produced by the process are higher alkyl glycosides useful as surfactants.
U.S. Pat. No. 3,598,865 (Lew) discloses the production of higher alkyl (C
−8
-C
25
) glycosides from a monosaccharide or source thereof and a higher monohydric alcohol in the presence of a latent solvent (lower alcohols) and an acid catalyst selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, phosphorous acid, toluenesulfonic acid, and boron trifluoride.
U.S. Pat. No. 3,219,656 (Boettner) discloses a process for producing a higher alkyl glycoside by reacting glucose with methanol in the presence of a macroreticular-structured sulfonic acid resin, anhydrous and in the acid form, to produce methyl glycoside which is reacted without isolation with butanol to form butyl glycoside and which in turn is reacted with a higher alcohol to form a surface active higher alkyl glycoside.
U.S. Pat. No. 3,839,319 (Mansfield) discloses a process for producing alkyl glycosides by direct, acid catalyzed reaction of a higher alcohol and a saccharide. The acid catalysts are mineral acids such as hydrochloric and sulfuric, and sulfonic acid exchange resins
An excellent review article was written by Barry Salka of Henkel Corporation in Vol. 108 p89-93 covering the chemistry and applications of alkyl glycosides in a variety of formulations. Salka points out that the degree of polymerization of glycoside is 1.4 on commercial products. This means that there are on average only 1.4 glucose units per alkyl group, resulting in a hydrophobic material. This significantly limits the suitability of this type of molecule in many applications, particularly in personal care and cosmetic applications. In fact commercial the predominant species in the commercial mixture (about 70% by weight) is the water insoluble mono product.
None of the patents referenced above provide for a molecule that has the necessary water soluble group incorporated to overcome the lack of water solubility, greasy drying feel that alkyl glycosides have on the skin.
The Invention
The present invention relates to the finding that the reaction of the rather hydrophobic alkyl polyglycosides with the proper reagent results in molecules that have improved water-solubility and consequently overcome many of the shortcomings of the alkyl polyglycosides itself. It is most interesting that the maximum amount of glycoside units per alkyl group that can be added using known technology is 1.5. This means that the product is a mixture of mono and di functional product. This product has the remaining fatty alcohol stripped off in an evaporative process. The resulting product is about 70% by weight of a product of a d.p. of 1, about 21% by weight of a product of a d.p. of 2, about 7% by weight of a product having a d.p. of 3, and about 2% by weight of a product that has a d.p. of 4.
We have surprisingly learned that taking the alkyl polyglycosides produced in the commercial process, with it's inherent lack of water solubility and reacting it to make non-ionic surface-active agents, results in a series of products that are much more usable in many applications. Simply put, alkyl polyglycosides make much better hydrophobic raw materials than finished surface-active agents. When some or all of the many hydroxyl groups are converted into cationic groups outstanding conditioning and water solubility results.
SUMMARY OF THE INVENTION
Alkyl polyglycosides are complex products made by the reaction of glucose and fatty alcohol. In dealing with the chemistry one talks about degree of polymerization (the so called “d.p.”). In the case of traditional alkyl polyglycosides the d.p. is around 1.4. This means that on average thee is 1.4 units of glucose for each alkyl group. The fact of the matter is that the resulting material is a mixture having an average of 1.4.
The specific structure of the product is hard to ascertain completely since many positional isomers are possible, but two examples of structures are as follows;
It should be clear that if there is a 50/50 mixture of the d.p. 1 and d.p. 2 product, the resulting analytical data will show that on average there is a d.p. of 1.5. Saying that a molecule has a d.p. of 1.5 does not mean that each molecule has 1.5 glucose units on it.
One key aspects of the present invention relates to the heretofore unappreciated fact that the rather hydrophobic alkyl polyglycosides contain on average five hydroxyl groups, one primary and the other four secondary. The assumption that there is a large degree of group specificity for the primary to react exclusively rather than the four additional hydroxyl groups is simply not true. This means that if on average only one of the five groups is reacted, there remains a very large concentration of reacting alkyl polyglycoside that has no functionality on it. Since the reactant with no functionalization remain water insoluble, there needs to be at lease 2 and as many as 4 hydroxyl groups functionalized to get to the desired water-soluble product. We have observed that when between 2 and 5 groups are reacted, a water-soluble very useful product results. Therefore it is a preferred embodiment having between 2 and 5 of the hydroxyl groups functionalized.
Another key unappreciated fact in making the compounds of the present invention is the fact that the alkoxylation reaction can if carried out in water using base catalyst results in a composition that contains (a) mono-glycoside alkoxylates, di-glycoside, (c) polyoxyalkylene glycol and the exact mixture of these compositions are key to the functionality of the products of the current invention.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of the present invention are mixtures conform to the following structures:
wherein;
R is alkyl having 8 to 22 carbon atoms;
R
1
, R
2
, R
3
and R
4
are independently selected from the group consisting of
—(CH
2
CH
2
O)
x
—(CH
2
CH(CH
3
)—O)
y
—(CH
2
CH
2
O)
z
—H
and H, with the proviso that R
1
, R
2
, R
3
,
Colonial Chemical Inc.
Henry Michael C.
Wilson James O.
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