Surfactant compositions and method therefor

A surfactant composition comprising from about 30 to about 50% by weight of a sulfated alkoxylated alcohol, an effective amount of an alkyl aryl sulfonate and an effective amount of a water soluble salt of a divalent acid, the composition being flowable or pumpable at normal handling temperatures.

BACKGROUND OF THE INVENTION 
The present invention relates to surfactant compositions and, more 
particularly, to flowable or pumpable compositions containing sulfated 
alkoxylated alcohols. 
Sulfated alkoxylated alcohols (ES) are used in many detergent applications. 
Substantially water free sulfated alkoxylated alcohols, particularly those 
containing greater than 5 moles of ethylene oxide per mole of alcohol, 
range from viscous liquids to gel like materials and are generally 
unpumpable or non-fluid at normal handling temperatures in the range of 
110.degree. to 120.degree. F. For ease of shipment and handling, it is 
desired that the ES materials be formulated into a fluid or pumpable form 
so that they can more easily and economically be converted into detergent 
end product. Generally speaking, aqueous ES compositions containing 25-30% 
by weight of the ES material in water are fluid. However, these "low 
active" liquid compositions are undesirable for several reasons. For one, 
because the concentration of the ES is so low, it requires excessive 
freight costs since more of the aqueous composition must be shipped in 
order to obtain the desired quantity of the active ingredient, i.e. the ES 
material. Additionally, since the compositions contain such large 
quantities of water, there are excessive energy costs in connection with 
spray drying to remove the water to obtain solids for incorporation into 
detergent powders. There are also restrictions upon the amount of other 
water containing ingredients used in formulating a mixture for spray 
drying to a detergent powder which make such "low active" compositions 
undesirable. 
Preferably, an ES composition which contains from about 30 to about 50% by 
weight of the sulfated alkoxylated alcohol would be desirable since it 
would overcome the disadvantages discussed above with respect to the low 
active compositions. Unfortunately, in the past it has been found that 
attempts to formulate compositions containing in excess of about 30% by 
weight ES material resulted in a material that yielded either a rigid gel 
or a highly viscous fluid which, in any event, was essentially unpumpable 
or non-fluid under normal handling conditions, i.e. from about 110.degree. 
F. to 120.degree. F. 
It is known to add lower alcohols, e.g. methanol, ethanol, etc., to high 
active ES solutions in order to reduce the viscosity and render them fluid 
or pumpable. However, the addition of such lower alcohols is undesirable 
since, in the spray drying operation to recover the ES product, the 
alcohols, which are vented from the spray dryer, must be recovered to 
minimize potential environmental problems meaning that the spray drying 
operation becomes more expensive. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a novel 
surfactant composition. 
Another object of the present invention is to provide a surfactant 
composition containing sulfated alkoxylated alcohol which is pumpable. 
Still another object of the present invention is to provide a surfactant 
composition comprising water and at least 30% by weight sulfated 
alkoxylated alcohol which is pumpable and free flowing at normal handling 
temperatures. 
A further object of the present invention is to provide a method of forming 
a free flowing, sulfated alkoxylated alcohol containing greater than 30% 
by weight ES material. 
The above and other objects of the present invention will become apparent 
from the description given herein and the appended claims. 
The surfactant composition of the present invention comprises a sulfated 
alkoxylated alcohol, an effective amount of an alkyl aryl sulfonate, and 
an effective amount of an inorganic, water soluble salt of a divalent acid 
such as carbonic acid or sulfuric acid, all of the above-named ingredients 
being present in an aqueous medium. 
The process of the present invention includes sulfating, with sulfur 
trioxide and other suitable sulfating agent, an alkoxylated alcohol to 
produce the sulfate ester, principally the half ester, of the alkoxylated 
alcohol followed by the addition of an alkyl aryl sulfonate or an alkyl 
aryl sulfonic acid and an inorganic, water soluble salt of a divalent 
acid, and an aqueous mixture of a basic material in sufficient 
concentration to neutralize the sulfate ester. In the case where the 
sulfonate is used, the sulfonate and aqueous mixture of the basic material 
must be added together to prevent degradation of the half ester. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The surfactants to which the composition of the present invention are 
directed and the sulfated alkoxylated alcohols having the formula: 
EQU R--OC.sub.2 H.sub.4 --.sub.x O--SO.sub.3 M I. 
wherein R is an alkyl radical having from about 10 to about 16 carbon 
atoms, x is from about 5 to about 9, M is a monovalent cation selected 
from the class consisting of alkali metal ions, ammonium ion and mixtures 
thereof. Preferably, the alkyl group will have from about 12 to about 14 
carbon atoms. The alcohol from which the alkyl radical is derived can be 
either synthetic or of natural origin as is well known to those skilled in 
the art. Non-limiting examples of naturally occurring fatty alcohols 
useful in the present invention include dodecyl alcohol, myristyl alcohol, 
cetyl alcohol, capryl alcohol, etc. The alkyl radical, i.e. the R group, 
can be either straight chain or branched chain although it is preferred 
that it be primarily straight chain. Preferably, the alkyl group is 
straight chain containing no more than approximately 15% branched chain 
material. 
The alcohols forming the R group of the sulfated alkoxylated alcohols can 
be ethoxylated in the well known fashion such as described, for example, 
in U.S. Pat. Nos. 3,297,412; 3,770,701; 3,894,093 and 3,956,401, 
incorporated herein by reference for all purposes. 
Particularly preferred as a starting product alcohol for preparation of the 
sulfated alkoxylated alcohols is a mixture of C.sub.12 -C.sub.14 alcohols 
containing approximately 35% by weight C.sub.12 alcohols and 65% by weight 
C.sub.14 alcohols with approximately 99% of said alcohols being linear. 
While the sulfated alkoxylated alcohol can contain from about 5 to about 9 
ethoxy groups per mole, it is preferred that the sulfated alkoxylated 
alcohols contain from about 6 to about 8 ethoxy groups per mole of 
sulfated ethoxylated alcohol. Especially desirable is a sulfated 
ethoxylated alcohol utilizing the C.sub.12 -C.sub.14 alcohols starting 
material noted above and having an average of about 6.7 ethoxy groups per 
mole of sulfated alkoxylated alcohol. 
Sulfating of the ethoxylated alcohols can be carried out in the well known 
manner by methods such as those taught in U.S. Pat. Nos. 3,227,145; 
3,309,392; 3,395,170 and 3,775,407, incorporated herein by reference for 
all purposes. The sulfated alkoxylated alcohol, in the final composition, 
will be present in the form of a salt thereof, the salt including a 
monovalent cation which is selected from the class consisting of alkali 
metal ions, ammonium ion and mixtures thereof. Preferably, because of 
solubility and ready availability, it is preferred that the cation be 
sodium ion or ammonium ion. 
The sulfated alkoxylated alcohol will be present in the composition of the 
present invention in an amount greater than about 30% by weight, 
preferably from about 30% to about 50% by weight of the composition. 
The composition of the present invention also contains an alkyl aryl 
sulfonate having the general formula: 
##STR1## 
wherein R.sub.1 is an alkyl radical having from about 10 to about 15 
carbon atoms, preferably from about 12 to about 14 carbon atoms, Z and 
Z.sub.1 are hydrogen or an alkyl group having up to 2 carbon atoms, and 
M.sub.1 is a monovalent cation selected from the class consisting of 
alkali metal ions, ammonium ion and mixtures thereof. The alkyl aryl 
sulfonates contemplated by the present invention include those in which 
the alkyl radical, i.e. the R group, is linear or branched chain and 
includes such compounds as sodium tridecylbenzene sulfonate, sodium 
dodecylbenzene sulfonate, sodium tetradecylbenzene sulfonate, sodium 
tridecyltoluene sulfonate, sodium tridecylxylene sulfonate, etc. The alkyl 
aryl sulfonate will be present in an effective amount, i.e. an amount 
which when combined with the inorganic, water salt described hereafter, 
will provide a fluid or pumpable composition, in an aqueous medium, under 
normal handling conditions. Preferably, the alkyl aryl sulfonate will be 
present in an amount of about 7% or greater, preferably from about 7 to 
about 30% by weight of the composition. 
In addition to the sulfated alkoxylated alcohol and the alkyl aryl 
sulfonate, the composition of the present invention also includes an 
inorganic, water soluble salt of a divalent acid. Suitable non-limiting 
examples of divalent acids include sulfuric acid, carbonic acid, etc. 
Preferably, the water soluble salt includes a cation selected from the 
class consisting of alkali metal ions, ammonium ion and mixtures thereof. 
Thus, salts such as sodium carbonate, sodium sulfate, ammonium carbonate, 
ammonium sulfate, potassium sulfate, etc. are suitable for use as the 
inorganic, water soluble salt of the present invention. The water soluble 
salt is present in the composition in an effective amount, an effective 
amount being that amount which, when combined with the alkyl aryl 
sulfonate, will maintain the alkylated sulfonated alcohol in a flowable, 
pumpable or fluid condition in an aqueous medium. It will be apparent that 
the amount of the water soluble salt will depend upon the amount and 
composition of the sulfated alkoxylated alcohol and the amount of the 
alkyl aryl sulfonate present in the composition. Generally, however, the 
water soluble salt is present in an amount of from about 3 to about 7% by 
weight of the composition. 
In forming the compositions of the present invention, an alkyl aryl 
sulfonic acid can be employed rather than the alkyl aryl sulfonate 
described above. Thus, when the alkyl aryl sulfonic acid is employed, 
M.sub.1 noted above in Formula II would be hydrogen rather than one of the 
cations described. The order of addition of the ingredients in the process 
of the present invention is important. It is well known that when 
alkoxylated alcohols are sulfated, such as by the use of sulfur trioxide 
or other sulfating agents, the sulfate ester, and more particularly the 
half ester, is initially formed. This sulfate ester is generally unstable 
and will rapidly degrade unless neturalized to form the salt. This is 
conventionally done by the combination of the sulfate ester with an 
aqueous medium containing a basic material in an amount sufficient to 
neutralize the sulfate ester. While the basic material can be present in 
stoichimetric amounts, it is preferable that an excess of the basic 
material or neutralizing agent be present to insure that none of the ester 
form remains which might degrade and effect the properties, particularly 
color, or composition of the final end product. 
It is important that the sulfated ester not be neutralized prior to 
addition of the other ingredients. Once the sulfated alkoxylated alcohol 
has been neutralized, and if it is present in an aqueous mixture in an 
amount of about 30% or greater by weight, the mixture becomes a highly 
viscous or gel-like material which is not fluid or pumpable and, 
accordingly, cannot be handled under conventional handling procedures or 
temperatures, e.g. between about 110.degree. to about 120.degree. F. Thus, 
in the case where the alkyl aryl sulfonate is employed, several variations 
of the process of the present invention may be utilized. The inorganic, 
water soluble salt can be added to the substantially anhydrous sulfated 
alkoxylated alcohol in ester form followed by the rapid combination of the 
alkyl aryl sulfonate in admixture with the aqueous medium containing the 
basic material or neutralizing agent. Preferably, the inorganic water 
soluble salt, the alkyl aryl sulfonate and the aqueous medium containing 
the neutralizing agent are mixed together, prior to the combination with 
the sulfate ester. 
In the case where the alkyl aryl sulfonic acid rather than sulfonate is 
employed, it is possible to add the sulfonic acid and the inorganic, water 
soluble salt to the sulfated alkoxylated alcohol in ester form, and them 
combine this mixture with an aqueous medium containing a neutralizing 
agent. Alternately, and preferably, the sulfonic acid, the inorganic, 
water soluble salt and the aqueous medium containing the neutralizing 
agent can be added together prior to combination with the sulfate ester. 
The neutralizing agent or basic material can be any of those 
conventionally used in the sulfation process such as, for example, aqueous 
solutions of sodium hydroxide, ammonium hydroxide, etc. 
To more fully illustrate the present invention, the following non-limiting 
examples are presented.

EXAMPLE 1 
The alkoxylated alcohol used was one wherein the alkyl group had a 
distribution of 35% C.sub.12, 65% C.sub.14 with approximately 1% of the 
alkyl groups being branched chain. The alkoxylated alcohol had an ethylene 
oxide content of 59% by weight (approximately 6.7 ethoxy groups per mole 
of alcohol). Samples of the alkoxylated alcohol were sulfated with sulfur 
trioxide in the conventional manner to produce the sulfate ester. 
Immediately after each sulfation was completed, the mixture containing the 
sulfate ester of the alkoxylated alcohol was admixed with sodium 
tridecylbenzene sulfonate (LAS) and sodium sulfate in a caustic solution 
(Sample Nos. 1-4, 10 and 11), sodium tridecylbenzene sulfonate in a 
caustic solution (Sample Nos. 5 and 7) sodium sulfate in a caustic 
solution (Sample Nos. 6 and 8), or a caustic solution alone (Sample No. 
9). In all cases the caustic solution contained an excess of NaOH 
necessary to neutralize the sulfate ester. The appearance and viscosity of 
the resulting samples was observed. The results are given in Table 1 
below. 
TABLE 1 
__________________________________________________________________________ 
SAM- BROOKFIELD 
PLE TAR- 
TAR- TAR- VISCOSITY (#4 
NUM- 
GET GET GET % ACTUAL 
ACTUAL 
ACTUAL 
% FREE 
APPEARANCE 
SPINDLE, 60 RPM) 
BER % ES 
% LAS 
NA.sub.2 SO.sub.4 
% ES % LAS % NA.sub.2 SO.sub.4 
OIL* AT 130.degree. F. 
AT 110.degree. 
AT 130.degree. 
__________________________________________________________________________ 
F. 
1 35 10 4 36.7 12.1 4.2 2.1 Mobile slurry 
5300 
6650 
2 35 10 4 37.4 11.0 3.9 1.1 Mobile slurry 
&gt;10000 
2850 
3 45 10 4 46.3 11.2 4.2 2.1 Mobile slurry 
8300 
7150 
4 45 10 4 39.6 8.8 5.8 2.8 Mobile slurry 
&gt;10000 
9200 
5 35 10 0 -- -- -- -- Firm paste 
-- -- 
6 35 0 10 -- -- -- -- Soft paste & 
-- -- 
watery layer 
7 45 10 0 -- -- -- -- Hard paste 
-- -- 
8 45 0 10 -- -- -- -- Hard paste 
-- -- 
9 35 0 0 -- -- -- -- Hard paste 
-- -- 
10 35 3 4 -- -- -- -- 2-Phase soft paste 
-- -- 
11 45 3 4 -- -- -- -- Hard paste 
-- -- 
__________________________________________________________________________ 
*Unsulfated material. 
As can be seen from Table 1 above, Samples 1-4 containing both LAS and 
sodium sulfate produced a mobile slurry, i.e. were pumpable or fluid at 
temperatures of 130.degree. F. or less. As can also be seen, Samples 5-11, 
which contained either LAS or sodium sulfate or no additives, or 
insufficient amounts of LAS are non-fluid and were found to remain 
non-fluid even up to temperatures of around 150.degree. F. At sustained 
temperatures of about 150.degree. F., these materials began to develop 
colored by-products making them less desirable for end use detergents. 
EXAMPLE 2 
The procedure of Example 1 was followed with the exception that the final 
composition contained 35% by weight ES, 10% by weight LAS and 4% by weight 
sodium carbonate. It was found that this composition provided a mobile 
foamy slurry at between 110.degree. and 130.degree. F. 
It can be seen from the above data that the present invention provides a 
sulfated alkoxylated alcohol composition containing greater than 30% by 
weight of the sulfated alcohol which is pumpable or flowable. 
The invention may be embodied in other specific forms without deparating 
from the spirit or essential characteristics thereof. The foregoing 
embodiments are therefore to be considered, in all respects, as 
illustrative and not restrictive, the scope of the invention being 
indicated by the appended claims rather than by the foregoing description, 
and all changes which come within the meaning and range of equivalence of 
the claims are therefore intended to be embraced therein.