Polymeric ethylene oxide/propylene oxide or ethylene oxide/butylene oxide ether carboxylic acids, a process for their preparation and their use

Polymeric ethylene oxide/propylene oxide or ethylene oxide/butylene oxide ether carboxylic acids of the formula ##STR1## wherein R denotes methyl or ethyl, preferably methyl, A denotes hydrogen or a metal cation, preferably Na.sup.(+) or K.sup.(+), X and Z together denote a number from 2 to 360, preferably from 2 to 140, y denotes a number from 15 to 70, preferably from 25 to 70 and n denotes a number from 1 to 10, a process for their preparation and their use as surfactants.

Block polymers of ethylene oxide/propylene oxide, having the general 
formula 
##STR2## 
are known as low foaming non-ionic surfactants for universal use and are 
commercially available as such. The introduction of carboxyl groups into 
non-ionics of this type, for instance by reaction of alkyloxyethylates 
with chloroacetic acid, provides anionic compounds having a markedly 
changed spectrum of action. 
The present invention relates to new ether carboxylic acid derivatives of 
ethylene oxide/propylene oxide or butylene oxide polymers, having the 
formula I 
##STR3## 
wherein R denotes methyl or ethyl, preferably methyl, A denotes hydrogen 
or a metal cation, preferably Na.sup.(+) or K.sup.(+), X and Z together 
denote a number from 2 to 360, preferably from 2 to 140, y denotes a 
number from 15 to 70, preferably from 25 to 70 and n denotes a number from 
1 to 10. 
The compounds of the formula I above are prepared by reacting a compound of 
the formula II 
##STR4## 
in the presence of an acid catalyst, with glyoxylic acid and then, if 
appropriate, neutralizing. 
The diphenyl ethers of the formula II serving as starting compounds are 
obtained by initially chlorinating, by known processes, an ethylene 
oxide/propylene oxide or butylene oxide block polymer of the formula III 
##STR5## 
for example with thionyl chloride alone or in an inert solvent, at 
temperatures from 80.degree. to 120.degree. C., preferably at 90.degree. 
C. The 1,.omega. -dichloro compound of the formula IV thus obtained 
##STR6## 
is then reacted with an alkali metal phenolate in a relatively high 
boiling alcohol, preferably isobutanol, at its boiling point. 
The reaction of the 1,.omega.-diphenyl ether of the formula II with 
glyoxylic acid is carried out in the presence of an acid catalyst (a Lewis 
acid), for example zinc chloride. Glyoxylic acid monohydrate can also be 
employed instead of glyoxylic acid. In this case, it is advisable to add a 
water-binding reagent, such as, for instance, concentrated sulfuric acid. 
Glacial acetic acid preferably serves as the reaction medium, and the 
reaction is carried out at 70.degree.-120.degree. C., preferably 
90.degree. C. The molar ratio of the reactants is 1.5 moles of glyoxylic 
acid to one mole of the 1,.omega.-diphenyl ether. Polymers are obtained as 
the final product, the chain length of which can be approximately given by 
the numbers from 1 to 10 for the index n in the formula I. If, in the 
compound of the formula I, A is intended to represent a cation, the 
compounds obtained in the reaction described above are subsequently 
neutralized with the equivalent amount of a base, preferably with sodium 
or potassium hydroxide. 
The products according to the invention are yellow to dark brown, in some 
cases highly viscous, compounds, which can be diluted, at pH values above 
6, in every ratio with water or water/alcohol mixtures. Since they are 
anion-active substances having non-ionic structure elements, they can find 
many uses as surfactants. They are distinguished by good wetting and 
dispersing properties and are valuable dyeing auxiliaries and emulsifiers. 
GENERAL PREATION OF THE 1,.omega. -DICHLORO COMPOUNDS IV 
2.4 moles of thionyl chloride are allowed to run into 1 mole of a diol of 
the general formula III, at 50.degree. C. with stirring, at such a rate 
that the internal temperature does not rise above 90.degree. C. This 
temperature is maintained for 3 hours, the acid gases are removed by 
passing through a powerful stream of N.sub.2, and the dichlorides are 
obtained in almost quantitative yield. 
GENERAL PREATION OF THE 1,.omega.-DIPHENYL ETHERS II 
1 mole of a dichloride IV, together with 2.05 moles of phenol and 2.05 
moles of KOH, are heated under reflux in isobutanol for 10 hours. The 
precipitated KCl is filtered off and the solvent is removed by 
distillation in vacuo. The 1,.omega.-diphenyl ethers are obtained in good 
yields. 
GENERAL PREATION OF THE ETHER CARBOXYLIC ACIDS I 
1 mole of a 1,.omega.-diphenyl ether II is brought to reaction with 1.5 
moles of glyoxylic acid monohydrate, catalytic amounts of ZnCl.sub.2 and 
1.5 moles of concentrated H.sub.2 SO.sub.4 in glacial acetic acid at 
90.degree. C. for 10 hours. The solution is filtered off or decanted off 
from the ZnCl.sub.2, the glacial acetic acid is removed by distillation in 
vacuo and the solution is neutralized. The ether carboxylic acids I or 
their salts are obtained in good yields.

EXAMPLE 1 
774 g (0.4 mole) of an ethylene oxide/propylene oxide block polymer with a 
PyO block of 1,750 plus about 10% of EO, molecular weight: 1935 from the 
OH number, were reacted, in steps, in accordance with the general methods 
of preparation described above, with SOCl.sub.2, phenolate and glyoxylic 
acid to give 772 g (90% of theory) of the ether carboxylic acid Ia. 
(Ia: R=CH.sub.3, A=H, X+Z=4.2, y=30) 
EXAMPLE 2 
Starting from an ethylene oxide/propylene oxide block polymer with a PyO 
block of 1,750 plus about 20% of EO, molecular weight: 2550 from the OH 
number, the compound Ib (R=CH.sub.3, A=H, X+Z=18.2 and y=30) was obtained 
in the same manner in a yield of 88% of theory. 
EXAMPLE 3 
Starting from an ethylene oxide/propylene oxide block polymer with a PyO 
block of 1,750 plus about 40% of EO, molecular weight: 2700 from the OH 
number, the compound Ic (R=CH.sub.3, A=H, X+Z=21.6 and y=30) was obtained 
in the same manner in a yield of 91% of theory.