Process for improving the color quality in the preparation of polyoxyalkylene glycol dialkyl ethers in the presence of atmospheric oxygen

1 . A process for converting free hydroxyl groups of a polyoxyalkylene glycol or a polyoxyalkylene glycol monoether or a mixture thereof by

reacting a starting material of at least one polyoxyalkylene glycol or at least one polyoxyalkylene glycol monoether with a base to form a reaction intermediate, and

alkylating or acylating the reaction intermediate with at least one halohydrocarbon or acid halide in the presence of a reducing agent, the alkylation or acylation reaction being performed in the presence of atmospheric oxygen in a supernatant gas phase to provide a reaction product.

2 . The process as claimed in claim 1 , wherein the content in the supernatant gas phase of atmospheric oxygen during the alkylation or acylation reaction is between 0.001 and 20% by volume.

3 . The process as claimed in claim 1 , wherein the reaction product has a Hazen color number of less than 500.

4 . The process of claim 1 , wherein the reaction product corresponds to the formula 1

R—O-(AO) y —R 1   (1)

in which

R is hydrogen, a hydrocarbon group having from 1 to 24 carbon atoms or an R*—C(O)— group,

R* is a hydrocarbon group having from 1 to 24 carbon atoms,

R 1 is a hydrocarbon group having from 1 to 24 carbon atoms,

AO is an alkoxy group, and

y is from 1 to 200.

5 . The process of claim 1 , wherein the starting material is a compound of formula 2

H—O-(AO) y —H  (2)

or reactants of the formula 3

H—O-(AO) y —R 1   (3)

in which

R 1 is a hydrocarbon group having from 1 to 24 carbon atoms,

AO is an alkoxy group, and

y is from 1 to 200.

6 . The process of claim 4 , wherein y is from 2 to 100.

7 . The process of claim 4 , wherein R 1 is a hydrocarbon radical having from 2 to 4 carbon atoms.

8 . The process of claim 1 , wherein the reducing agent is selected from the group consisting of a borohydride, an aluminohydride, and mixtures thereof, wherein the borohydride has the formulae BH 4 , MBH 3 R 2 , MBH 2 (R 2 ) 2 , or MBH(R 2 ) 3 and the aluminohydride has the formulae AlH 4 , MAlH 3 R 2 , MAlH 2 (R 2 ) 2 , or MAlH(R 2 ) 3 , in which M is an alkali metal ion selected from the group consisting of lithium, sodium, and potassium, and R 2 is CN or (OC n H 2n+1 ) m where n=1-5 and m=1-4.

9 . (canceled)