Field of the Invention:

The present invention generally relates to a novel

surfactant and process for making same. More particularly,

it has been surprisingly found that an anionic/nonionic

surfactant mixture having enhanced surface-active

properties can be obtained by co-sulfating/sulfonating a

solid-form nonionic sugar surfactant.

Background of the Invention:

Sugar surfactants, for example alkyl oligoglucosides

or fatty acid-N-alkyl glucamides, are distinguished by

excellent detergent properties and high ecotoxicological

compatibility. For this reason, these classes of nonionic

surfactants are acquiring increasing significance. They

are generally used in liquid and powder formulations, for

example laundry and dishwashing detergents and hair

shampoos. However, because of their increased desirability

as surface active agents, their use as surfactants in many other types of products is growing rapidly.

While conventional sugar surfactants perform

satisfactorily in many applications, there is a constant

need to both enhance and expand their performance

properties. Methods of improving the performance of

conventional sugar surfactants by increasing: their foaming

and foam stability, tolerance to water hardness and

detergency, continue to be sought. Moreover, the use of

sugar surfactants in topical skin products also requires a

reduction in their tendency towards skin and eye

irritation.

Summary of the Invention:

The present invention provides a novel surfactant

product formed by a process involving the steps of :

(1) providing a solid water-free sugar surfactant;

(2) providing a co-reactant selected from the group

consisting of alpha-olefins, internal olefins, linear

alkylbenzene, branched alkylbenzene, fatty alcohol,

alkoxylated fatty alcohol, secondary alkanes, N-

methylglucamide, tall oil, napthalene, xylene, cumene,

toluene, dodecylbenzene, and mixtures thereof;

(3) dispersing or dissolving the sugar surfactant in

the co-reactant to form a feed mixture; and

(4) sulfating/sulfonating the feed mixture to form a

surfactant product .

The present invention is also directed to a surfactant

composition containing:

(a) an unreacted solid water-free sugar surfactant;

(b) an unreacted co-reactant selected from the group

consisting of alpha-olefins, internal olefins, linear

alkylbenzene, branched alkylbenzene, fatty alcohol,

alkoxylated fatty alcohol, secondary alkanes, N-

methylglucamide, tall oil, napthalene, xylene, cumene,

toluene, dodecylbenzene, and mixtures thereof;

(c) a sulfated/sulfonated derivative of the solid

water-free sugar surfactant of component (a) ; and

(d) a sulfated/sulfonated derivative of the co-

reactant of component (b) .

Description of the Invention:

Other than in the operating examples, or where

otherwise indicated, all numbers expressing quantities of

ingredients or reaction conditions used herein are to be

understood as being modified in all instances by the term

"about" . The novel surfactant mixture of the present invention

is derived from the co-sulfation/sulfonation of nonionic

sugar surfactants. Suitable nonionic sugar surfactants

include, but are not limited to alkyl and alkenyl

oligoglycosides and fatty acid N-alkyl

polyhydroxyalkylamides . Alkyl and alkenyl oligoglycosides

are known nonionic surfactants corresponding to general

formula (I) :

RH)- [G]

in which R ¹ is an alkyl and/or alkenyl radical containing 4

to 22 carbon atoms, G is a sugar unit containing 5 or 6

carbon atoms and p is a number of 1 to 10. They may be ob¬

tained by the relevant methods of preparative organic

chemistry.

The alkyl and/or alkenyl oligoglycosides may be

derived from aldoses or ketoses containing 5 or 6 carbon

atoms, preferably glucose. Accordingly, the preferred

alkyl and/or alkenyl oligoglycosides are alkyl and/or

alkenyl oligoglucosides .

The index p in general formula (I) indicates the

degree of oligomerization (DP degree) , i.e. the distribu¬

tion of mono- and oligoglycosides, and is a number of 1 to

10. Whereas p in a given compound must always be an

integer and, above all, may assume a value of 1 to 6, the

value p for a certain alkyl oligoglycoside is an analyti-

cally determined calculated quantity which is generally a

broken number. Alkyl and/or alkenyl oligoglycosides having

an average degree of oligomerization p of 1.1 to 3.0 are

preferably used. Alkyl and/or alkenyl oligoglycosides

having a degree of oligomerization of less than 1.7 and,

more particularly, between 1.2 and 1.4 are preferred from

the applicational point of view.

The alkyl or alkenyl radical R ¹ may be derived from

primary alcohols containing 4 to 11 and preferably 8 to 10

carbon atoms. Typical examples are butanol, caproic

alcohol, caprylic alcohol, capric alcohol and undecyl

alcohol and the technical mixtures thereof obtained, for

example, in the hydrogenation of technical fatty acid

methyl esters or in the hydrogenation of aldehydes from

Roelen's oxosynthesis. Alkyl polyglycosides having a chain

length of C ₈ to C ₁₀ (DP = 1 to 3) , which are obtained as

first runnings in the separation of technical C _8-18 coconut

oil fatty alcohol by distillation and which may contain

less than 6% by weight of C ₁₂ alcohol as an impurity, and also alkyl polyglycosides based on technical C _9/11

oxoalcohols (DP = 1 to 3) are preferred.

In addition, the alkyl or alkenyl radical R ¹ may also

be derived from primary alcohols containing 12 to 22 and

preferably 12 to 14 carbon atoms. Typical examples are

lauryl alcohol, myristyl alcohol, cetyl alcohol, palmito-

leyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl

alcohol, elaidyl alcohol, petroselinyl alcohol, arachyl

alcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol,

brassidyl alcohol and technical mixtures thereof which may

be obtained as described above. Alkyl oligoglucosides

based on hydrogenated C ₁₂₁₄ coconut oil fatty alcohol having

a DP of 1 to 3 are preferred.

Fatty acid N-alkyl polyhydroxyalkylamides are nonionic

surfactants corresponding to formula (II) :

R ³

R ² CO-N- [Z] (II)

in which R ² CO is an aliphatic acyl radical containing 6 to

22 carbon atoms, R ³ is hydrogen, an alkyl or hydroxyalkyl

radical containing 1 to 4 carbon atoms and [Z] is a linear or branched polyhydroxyalkyl radical containing 3 to 12

carbon atoms and 3 to 10 hydroxyl groups.

The fatty acid N-alkyl polyhydroxyalkylamides are

known compounds which may normally be obtained by reductive

amination of a reducing sugar with ammonia, an alkylamine

or an alkanolamine and subsequent acylation with a fatty

acid, a fatty acid alkyl ester or a fatty acid chloride.

The fatty acid N-alkyl polyhydroxyalkylamides are preferably derived from reducing sugars containing 5 or 6

carbon atoms, more particularly from glucose. Accordingly,

the preferred fatty acid N-alkyl polyhydroxyalkylamides are

fatty acid N-alkyl glucamides which correspond to formula

(III) :

R ³ OH OH OH

R ² CO-N- CH,- CH- CH-CH-CH- CH,OH ( I I I ]

OH

Preferred fatty acid N-alkyl polyhydroxyalkylamides

are glucamides corresponding to formula (III) in which R ³ is

hydrogen or an alkyl group and R ² CO represents the acyl

component of caproic acid, caprylic acid, capric acid,

lauric acid, myristic acid, palmitic acid, palmitoleic

acid, stearic acid, isostearic acid, oleic acid, elaidic

acid, petroselic acid, linoleic acid, linolenic acid,

arachic acid, gadoleic acid, behenic acid or erucic acid or

technical mixtures thereof. Fatty acid N-alkyl glucamides

(III) obtained by reductive amination of glucose with

methylamine and subsequent acylation with lauric acid or

G ₁₂ i ₄ coconut oil fatty acid or a corresponding derivative

are particularly preferred. In addition, the

polyhydroxyalkylamides may also be derived from maltose and

palatinose.

Commercially available sugar surfactants, such as

those listed above, are offered in aqueous form and contain

certain levels of both water and contaminants. While this

form is generally acceptable in most formulation cases, it

is unacceptable for purposes of the present invention. The

presence of water and contaminants in these types of

aqueous sugar surfactants results in the formation of

unwanted sulfuric and/or hydrochloric acid and other

degradation products because of the contaminants '

reactivity during the sulfation/sulfonation process. Thus,

the sugar surfactants used as starting materials for the

present invention must possess very low levels of

degradation (contamination) and little, if any, water.

Moreover, it is preferred that the solid water-free

sugar surfactants, in powder or granular form, also possess

an apparent density above 500 g/1.

Due to the above-identified disadvantages associated

with the use of commercially available aqueous sugar

surfactants, the present invention employs a solid water-

free sugar surfactant, preferably in either powder or

granular form, which is also referred to as a flash dried

sugar surfactant.

One example of how such solid water-free (flash dried)

sugar surfactants can be produced involves the simultaneous

drying and granulating of water-containing pastes of sugar

surfactants. The simultaneous drying and granulation

process takes place in a horizontally arranged thin-layer

evaporator with rotating fittings of the type marketed, for

example, by the VRV company under the name of "flash

dryer". In simple terms, the flash dryer is a tube which

can be heated to different temperatures over several zones.

The paste-form starting material, which is introduced by a

pump, is projected onto the heated wall by one or more

shafts fitted with paddles or plowshares as rotating

fittings and is dried on the heated wall in a thin layer

typically with the thickness of 1 to 10 mm. According to

the invention, it has been found to be of advantage to

apply a temperature gradient of 170°C (product entrance) to

20 ^β C (product exit) to the thin layer evaporator. To this

end, the first two zones of the evaporator for example may

be heated to 160°C and the last zone to 20°C. Higher drying

temperatures have not been found to be of advantage in view

of the thermal lability of the starting materials. The

thin-layer evaporator is operated at atmospheric pressure.

Air is passed through in countercurrent (throughput 50 to

150 m ³ /h) . The gas entry temperature is generally in the

range from 20 to 30°C while the exit temperature is in the

range from 90 to 110°C.

The water-containing sugar surfactant pastes which may

be used as starting materials may have a solids content

above 20% by weight and preferably in the range from 25 to

75% by weight. Typically, their solids content is of the

order of 30 to 50% by weight. The throughput is of course

dependent on the size of the dryer, but is typically in the

range from 5 to 15 kg/h. It is advisable to heat the

pastes to 40 to 60°C during their introduction.

In addition, after drying, it has proved to be of

considerable advantage to transfer the granules, which

still have a temperature of around 50 to 70 ^C C, to a conveyor

belt, preferably in the form of a vibrating shaft, and

rapidly to cool them thereon, i.e. over a period of 20 to

60 seconds, to temperatures of around 30 to 40°C using

ambient air. In order to further improve their resistance

to the unwanted absorption of water, the granules may also

be subsequently dusted with 0.5 to 2% by weight of silica

powder.

It should be noted that while the above-described

process of forming suitable solid water-free (flash dried)

sugar surfactants is exemplified, any other method of

forming solid sugar surfactants which are substantially

both water- and contaminant-free, i.e., containing little,

if any, water and contaminants, may be employed without

12 departing from the spirit of the invention.

The flash dried sugar surfactant starting materials,

substantially free of both water and contaminants, are then

dispersed or dissolved in a co-reactant to form a feed

mixture. Examples of suitable co-reactants include, but

are not limited to, alpha-olefins, internal olefins, linear

alkylbenzene, branched alkylbenzene, fatty alcohols,

alkoxylated fatty alcohols, secondary alkanes, N-

methylglucamides, tall oil, napthalene, xylene, cumene,

toluene, dodecylbenzene, and mixtures thereof. A

particularly preferred co-reactant is an alkoxylated fatty

alcohol. In general, the mixture feed should contain a

sugar surfactant solids content ranging from about 0.5 to

about 99.5% by weight, based on the weight of the mixture

feed.

Once the mixture feed is formed, it is then subjected

to a sulfation/sulfonation process. The sulfation and/or

sulfonation of organic compounds is well known in the art.

There are primarily two types of reactions between an

organic compound and sulfuric acid reactants: sulfation

which produces sulfates having C-OS- linkages, and

sulfonation which produces sulfonates having C-S linkages.

The sulfation/sulfonation process generally involves

reacting the organic compound to be sulfated and/or

sulfonated with either concentrated sulfuric acid/oleum,

chlorosulfonic acid or sulfurtrioxide. The type of

equipment and specific reaction conditions associated

therewith which are employed to perform this process are

well known in the art, an example of which is U.S. Patent

No. 4,973,686 issued to Henkel KGaA on November 27, 1990,

the entire contents of which are incorporated herein by

reference.

The resultant surfactant product formed by the above-

disclosed process contains a mixture of unreacted water-

free sugar surfactant, unreacted co-reactant, sulfated

and/or sulfonated derivatives of the water-free sugar

surfactant, and sulfated and/or sulfonated derivatives of

the co-reactant, all of which comprise the surfactant

product .

The surfactant product may subsequently be

neutralized, in order to attain a pH ranging from about 5

to about 9, with an alkali material in order to form a

neutralized final surfactant product. Suitable alkali

materials include, but are not limited to, sodium

hydroxide, magnesium hydroxide, calcium hydroxide, TEA, and

the like. It is this final surfactant product which

possesses both anionic and nonionic surfactant

characteristics, thereby imparting improved surface active

properties, enhanced levels of foaming and foam stability,

better detergency, and increased water solubility, onto

products utilizing it as a surfactant component in their

formulation.

The particular amount of surfactant product to be used

in formulating a cleaning composition, whether it be a

laundry detergent, dishwashing detergent, hair shampoo and

the like, will be easily determined by those skilled in the

formulation of a specific cleaning composition.

EXAMPLE

A sulfonated/sulfated surfactant in accordance with

the present invention can be formulated by mixing about 75%

by weight of a solid, water-free, i.e., flash dried, alkyl

polyglycoside with about 25% by weight of an alkoxylated

fatty alcohol to form a feed mixture. The feed mixture can

then be sulf ted/sulfonated by reacting the feed mixture

with sulfurtrioxide to form the novel surfactant

composition of the invention.