DE1133556B - Process for bleaching polyalkylene ethers - Google Patents

Description

INTERNAT. KL. C 08 g

GERMAN

PATENT OFFICE

M 44229 IVd / 39 c

REGISTRATION DATE: 5th F E B RU AR 1960

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: JULY 19, 1962

The invention relates to a method for bleaching polyalkylene ethers, the to bleaching product with a complex borohydride, e.g. B. an alkali metal borohydride, in contact is brought.

The term "polyalkylene ether" used here includes polyalkylene glycols of the formula

H (OR) _n OH,

wherein R is an alkylene radical, e.g. B. Ethylene or propylene radical and η is an integer greater than 1. The abovementioned name also includes polyalkylene glycol derivatives of the formula

H (OR) _n X,

wherein R and η are as defined above and X is the residue of an organic compound having a reactive hydrogen atom, e.g. B. an amine, alcohol, phenol or a carboxylic acid. They are prepared by adding an alkylene oxide, such as ethylene oxide or propylene oxide, to water or compounds containing reactive hydrogen atoms (such as those mentioned above). It has been found that the compounds thus obtained are easily discolored if the reaction conditions are not controlled with a high degree of accuracy.

According to the invention it was found that this disadvantage can be eliminated and the discolored Polyalkylene ethers can be bleached by contacting them with complex borohydrides brings. The complex boron hydrides to be used according to the invention primarily comprise But also alkali metal borohydrides, such as lithium borohydride, sodium borohydride and potassium borohydride Borohydrides of other metals such as magnesium, calcium, barium and strontium borohydride.

The bleaching effect of the complex borohydrides compared to the polyalkylene ethers appears to be specific to be by trying to bleach other dark colored substances with complex borohydrides only in exceptional cases led to a noticeable reduction in color.

The amount of complex borohydride used to bleach polyalkylene ethers may need to be, depending on the initial color of the substance to be treated and the extent desired the diminution of color vary considerably. If the material to be treated only If the color is weak, then a very small amount of the bleach can produce the desired effect to lead. Therefore, in such cases, a naming procedure can be used for bleaching polyalkylene ethers

Applicant:

Mo och Domsjö Aktiebolag, Örnsköldsvik (Sweden)

Representative: Dr.-Ing. F. Wuesthoff, Dipl.-Ing. G. Pulse and Dipl.-Chem. Dr. rer. nat. E. Frhr. v. Pechmann, patent attorneys, Munich 9, Schweigerstr. 2

Dr. Paul Magnus Torkel Matell,

Alfredshem (Sweden) has been named as the inventor

value reduction of the color by an amount of 0.001 «/ 0 (based on the weight of the substance to be treated); however, if the substance is more colored, then it is generally necessary to use at least 0.1%, preferably 0.5%, in order to achieve the desired To achieve a reduction in color. If the substance to be treated is very darkly colored and if substantial bleaching is desired then it may of course be necessary, substantial Use larger amounts of the bleach. However, since complex borohydrides are expensive chemicals and the bleaching effect increases with increasing amounts of borohydride above a certain level The limit does not seem to increase significantly, it is usually advisable not to exceed 5%, preferably not more than 2 ° / o to be used.

The treatment temperature is not critical, and the treatment can be carried out at room temperature (25 ° C) or lower temperatures. Preferably however, higher temperatures are used, since the bleaching effect somewhat with increasing temperature increases. However, the temperature should not be so high that the treated material in one Decomposed to a significant extent, as this leads to the formation of new discolouring substances can. Preferably a temperature of 50 to 150 ° C is used.

Also, the treatment time is not of critical importance, as the bleaching effect is affected only insignificantly increased when the contact time

209 620/359

between the substance and the bleach is extended.

The lead treatment can thereby be carried out be that the complex borohydride in solid form or in a suitable solvent dissolved with the substance to be bleached or a solution of the same in a suitable solvent, such as water, ethanol, benzene, etc., provided that the complex Borohydride is sufficiently stable in the presence of the particular solvent.

In a special embodiment according to the invention, a complex borohydride can already be present in the manufacture of the polyalkylene ether, causing the appearance of a dark color in the Product can be prevented. Accordingly, this embodiment can be used as bleaching of the product be viewed during its formation.

The invention is explained in more detail by means of the following examples.

example 1

In a series of experiments various Polyäthylenäther were brought on the weight of the treated Polyäthylenäthers) in powder form in contact with relative l ⁰ / »{sodium borohydride. The mixture of the polyethylene ether and the sodium borohydride was left to stand at 120 ° C. for 1 hour. The color of the substance before and after the treatment was determined using the Gardner scale. The polyethylene ethers used and the results obtained are shown in Table I.

Table I. Example 2

A polyethylene ether produced by adding 7 moles of ethylene oxide to oleylamine with the Color 10 on the Gardner scale was treated with sodium borohydride. The conditions and Results are shown in Table II.

Table II

NaBH ₄ Time temperature colour
in Gardner Vo hours ⁰ C units 0.25 1 120 5 0.5 1 120 5 1.0 1 120 4th 0.5 2 120 4th 1.0 2 120 3

Example 3

A polyethylene ether of the same type as that of Example 2, but with the color 12 on the basis of Gardner scale, treated with sodium borohydride. The conditions and the results are compiled in Table III.

Table III

Polyethylene ether produced by adding η mol of ethylene oxide to A.

35

Water , .

Ethanol

Nonylphenol; ..

Lauryl alcohol

Tall oil fatty alcohol ......

Mixture of oleyl

and cetyl alcohol ...
Mixture of oleyl

and cetyl alcohol ...

Tall oil fatty acid

Oleylamine: ...

Oleylamine

Oleylamine

80
6th

Color untreated in Gardner units

10 9 1 6

6 to 7 11 10 12 14

treated

5 5 3 to 4

3 to 4

10

NaBH ₄ Time temperature colour
in Gardner »/ 0 hours ⁰ C units 1.0 1 120 6th 0.5 1 120 8th 0.5 1 120 7th 0.25 1 120 9 0.13 1 120 10 0.06 1 120 11 0.5 1 80 9 0.5 1 100 9 0.5 1 120 8th 0.5 1 120 7th 0.5 1 140 7th 0.5 1 160 6th 0.5 2 80 9 0.5 2 120 7th

Example 4

One by adding 6 moles of ethylene oxide Nonylphenol produced polyethylene ether with the color 9 on the basis of the Gardner scale was with Treated sodium borohydride. The conditions and results are summarized in Table IV.

Table IV

55

In another set of experiments, a number of other dark colored products, notably Aniline, nonylphenol, light tall oil, tall oil fatty acids, Rapeseed oil fatty acid ethanolamide and a still residue from the manufacture of 2-Ethy] hexanol treated with sodium borohydride under the same conditions as above. It was in the case of nonylphenol and tall oil fatty acid, a barely noticeable reduction in color was obtained, while the color of the other products did not change.

NaBH ₄ Time temperature colour
in Gardner % hours ⁰ C units 0.5 1 120 4th 0.2 1 120 4 to 5 0.5 2 120 3 0.2 2 120 3 to 4 0.5 1 150 3 0.2 1 150 4th 0.5 1 180 3 *) 0.2 1 180 4 *)

*) Change in color. The temperature is likely too high.

Poly
ethylene Solution Temperature Color in
Gardner units treated glycol middle U.N- 6th % ⁰ C treated 5 100 120 9 5 75 water 95 8th 75 toluene 95 8th

Example 5

A polyethylene glycol with a molecular weight of 300 was 0.5 weight percent Sodium borohydride, based on the polyethylene glycol, treated in the presence or absence of a solvent, the treatment was continued until the evolution of gas ceased. The terms and results are in the Table V compiled.

Table V Example 6

A polypropylene ether prepared by adding 8.5 moles of propylene oxide to oleylamine was made Treated with 0.5% sodium borohydride for 1 hour at 120 ° C, changing the color of 11 in 8 was changed using the Gardner scale.

Example 7

It was a polyethylene glycol with a molecular weight of 300 for 1 hour at 120 ° C with Treated 0.5% potassium borohydride, which reduced the color from 9 to 6 on the Gardner scale became.

Example 8

It was a 6O% ethanol solution of Polyethylene glycol with a molecular weight of 1 hour at 75 ° C with 0.3 percent by weight Lithium borohydride, based on the polyethylene glycol, treated, reducing the color of the solution decreased from 6 to 3 to 4 on the Gardner scale.

Example 9

20.7 kg of an 85% aqueous solution of one obtained by adding 30 mol of ethylene oxide to oleylamine produced polyethylene ether were treated for 1 hour at 90 ° C with 22 g of sodium borohydride, whereby the color was reduced from 11 to 8 on the Gardner scale.

Claims (5)

PATENT CLAIMS: 1. Process for bleaching polyalkylene ethers, characterized in that polyalkylene ethers are treated with a complex borohydride. 2. The method according to claim 1, characterized in that the complex borohydride an alkali metal borohydride is used. 3. The method according to claim 1, characterized in that an amount of 0.001 up to 5% of the complex borohydride, based on the weight of the polyalkylene ether, is used. 4. The method according to claim 1, characterized in that the treatment at Carries out temperatures of 50 to 150 ° C. 5. The method according to claim 1, characterized in that the treatment in the presence a suitable solvent. 30th © 209 620/359 7.62