DE1920327B - Process for the production of polyglycol ethers - Google Patents

Description

The large-scale industrial processes for the production of alcohols usually require that the resulting Raw products are more or less heavily contaminated by aldehydes or ketones. In all cases, however, where such alcohols are used as raw materials for the production of surface-active substances, such as. B. emulsifiers Laundry detergent. Dyeing auxiliaries, etc., are used, they are high for the subsequent oxyalkylation Demands purity. Removal of the indicated impurities by means of distillation is often not possible or at high cost due to similar boiling ranges as with alcohols connected. The elimination of the disruptive CO groups by switching on is also costly a hydrogenation stage in the production process.

The invention relates to a process for the production of polyglycol ethers by reaction of primary and secondary alcohols with 8 to 22 carbon atoms in the chain with alkali metals, Further reaction of the reaction mixture with alkylene oxides and customary work-up, characterized in that that primary and secondary alcohols containing aldehyde and ketone are used as starting materials used.

The alkylene oxides are ethylene oxide. Propylene oxide and its homologues and epichlorohydrin in question.

There are already primary, secondary or tertiary alcohols in the presence of extremely high amounts of Alkali also oxalkyhert in the form of alkali metals (German Auslegeschrift 1 130 176, 1 240 062; USA, patents 2 782 240, 3 100 230). However, these are pure alcohols that do not contain any CO groups. In the U.S. Patent 2 782 240. Column 2. Lines 37 to 40. is expressly made pointed out that crude alcohols contaminated with aldehydes, ketones and acids as Starting material for the oxyalkylation is unsuitable.

It was therefore not foreseeable that raw alcohols, which contain such impurities, without prior cleaning according to the eirfindungsgemeinschaft Processes to alkoxylate high quality products were, by using of alkali metal in one operation both the conversion of the carboxyl groups into Hydroxyl groups due to the resulting hydrogen and the activation of these OH groups by converting them into the alcoholates and the subsequent oxyalkylation will.

Another difference between the invention The working method compared to the cited older processes is the amount of Alkali metal. While in the cited patents, the amount of alkali metal alone based on the number of OH groups present in the starting material, i.e. a maximum of per J OH 1 alkali metal equivalent = 100 mol percent, it is expedient in the process according to the invention, when calculating the

the amount of alkali metal not only includes the alcoholic groups already present, but also the OH groups newly formed from the carbonyl groups, which must also be converted into the corresponding alcoholates in the desired amount before the oxyalkylation. Since both the OH number is jsgedrückt and the CO-Zahi definition <<in mg ΚΟΗ / Ί g of substance, one has to add only the OH value and the CO number and to calculate therefrom the theoretical amount of alkali metal, when a use of 100 mole percent of alkali metal is desired.

In contrast, the method of U.S. Patent No. 2,782,240 determines the amount of alkali metal calculated on the basis of the hydroxyl groups present. In the present case, however Depending on the content of carbonyl groups, a higher ratio of alkali metal can be used on a case-by-case basis to OH groups as I: 1. If you also in Idcalfall the amount of alkali metal accordingly the sum of the OH and CO numbers, you can, if this appears appropriate, work with a smaller amount of alkali metal, but this should be chosen so large. that the Conversion of the CO groups contained in the alcohols into OH groups is guaranteed in any case is. The resulting lower alcoholate formation, below 100 mol percent, is ζ. Β An advantage when using shorter-chain alcohols, the 100% alcoholates of which already have a more solid content Salt slurry and the use of an inert dispersant in the subsequent oxyalkylation would require.

The chosen amount of alkali metal can be added to the starting product all at once, but if so very high levels of CO groups are present, isi it is sometimes advantageous to reduce the amount of alkali metal zi subdivide and enter in several portions depending on the turnover of the alcoholic Groups to the alcoholate and the associated with it which release of hydrogen, through the ir statu nasccndi the CO groups to the alcoholic OH groups are to be reduced. Above all in the larger batches, because of the exothermic reaction when larger amounts are added, vot Alkali metal its division into a corresponding! Number of individual servings necessary

One works in the conversion of CO Gruppet and the alcoholate preferably such dal one to which, in a nitrogen atmosphere to 10 (up to 200 ⁰ C, preferably 130 to 150 ⁰ C, vorgewärmtei starting product adding the calculated amount of alkali metal at once or in portions, and under good stirring and permanent maintenance of the protective gas atmosphere the dissolution of the metal

leads to the end. ,

The pain is very important in all operations

lent exclusion of atmospheric oxygen and moisture

After dissolution of the alkali metal, which is also the case with long-chain chains at the temperatures involved Alcohols as Aveck for Special Applications as surfactants come into question, takes about 4 to 5 hours, is cooled when the reaction was carried out in a closed system, the residual hydrogen was removed by nitrogen and then carried out the oxyalkylation.

example 1

A mixture of secondary substances obtained by oxidation of a paraffin section was used Alcohols with an average molecular weight calculated from the OH number of 256.

The alcohol was of inferior quality because it still contained considerable amounts carbonyl group. containing material (CO number) as well as unsaturated compounds (iodine number) and non-oxidized Paraffin. The following key figures were determined for him:

OH number (hydroxyl number) 219

COZ (carbonyl number) 29.5

JZ (iodine number) 26.0

Residual paraffin over 7.0%

SZ (acid number) 1.3

VZ (saponification number) 9.2

iodine color count. '
(mg iodine in 100 ml water) 3.5

Way of working

Iu a 1-1-4 neck round bottom flask fitted with a stirrer, reflux condenser. Contact thermometer and a device for the simultaneous introduction of nitrogen and ethylene oxide are equipped, after the air in the flask has been displaced by nitrogen, 256 g sec. Alcohol (with the above figures) = I mol weighed in, in a lively stream of _{N 2.} which is dried by passing over KOH, heated to 130 ° C. and 20.7 g of sodium metal (bare cut surfaces! = 90 mol percent, based on OH groups, are introduced at 130 ° C. with thorough stirring and continuous NJ rinsing Heated to 150'C and the alcoholate formation was completed until the sodium had completely disappeared.

After dissolving the sodium, what is given below Conditions usually takes 4 to 5 hours to complete, is cooled back to 130C and started with the oxethylation.

At the same time as the alkylene oxide, some N ₂ is always passed through the apparatus, so that in all cases the entry of even the slightest traces of atmospheric oxygen is avoided. To control the nitrogen flow, a flow capillary with a manometer is connected to the reflux condenser at the gas outlet.

The uptake of alkylene oxide is exothermic and the reaction temperature must be reduced by appropriate cooling and the level of the ethylene oxide supply is kept at the specified level.

To control the progress of the reaction

A sample was taken, adjusted to pH 6 with hydrochloric acid, dried sharply, and the precipitated The salt is separated off and the cloud point is determined in the usual way.

After uptake of 484 g of ethylene oxide = 11.0 mol was in a solution of 5 g of sample in 25 ml of a 25% butyl diglycol solution found a cloud point of 82.7 ° C.

The whole experimental approach was now on 30 bis Cooled to 40 ° C. and also adjusted to pH 6 with HCl; after drying it got hot (approx 80 C) separated from the salt and the salt pressed out sharply. In the salt, only 1% of the total yield.

With a starting alcohol with an iodine color number of 3.5, a raw Oxäthy'.at with an iodine color number of 1.5 was obtained, which could be bleached to an iodine color number below 1 _{by treatment with H 2} O _2.

The oxyethylate was water-clear and whitened completely even when left standing for a long time at room temperature blank and without opacifying excretions. The following key figures were determined for this:

35

OHZ COZ 85.1
G.73

Taking into account the above-mentioned uptake of 484 ρ ethylene oxide, these key figures for the oxyethylate can be calculated back to the hypothetical values of the starting alcohol after the sodium treatment. The degree of conversion of the carbonyl groups into new OH groups accessible to oxyalkylation can be determined from the increase in the OH number compared to the initial OH number and the decrease in the CO number. Theoretically, the decrease in COZ must correspond to an equally high increase in the OHZ: when assessing these figures, the error limit of the determination methods and any side reactions must of course be taken into account.

Table Example I.

Oxethylal

OH number 85.1.
CO number 0.75

Slart alcohol

after

Na treatment (calculated values)

246

2.17

Starting alcohol

219 29.5 Difi.

% Sales? the CO group after

OHZ increase

91.5

COZ acceptance

92.7

example

According to Example 1, 100 g of secondary alcohol with MW 256 = 0.39 mol with 8.4 g of sodium metal = 93 mol percent OH groups transferred into the alcoholate and the experimental approach for comparison purposes without subsequent Oxalkylation neutralized and worked up. For the ethylene oxide-free alcohol obtained the following values were found after the sodium treatment:

Table example

Siiirtiilknhol after Nii-Dehuiullung
Igcfundcnc values!

Siiirtnlkohul

V _n Umsiil / dur CO group
after

OIIZ attachment

COZ-Abnahiiu

OH number 246.3
CO number 1.45

219.0
29.5

92.5

95.0

Example 3

From the used in Example 1 sec. Alcohol became the first by distilling off in vacuo Chelon-rich Fraklion cut out and used as starting material. These were the following Key figures determined:

OHZ 294.5, from this MG: 190

COZ 46.2

99 g sec. Alcohol (ketone-rich fraction) = 0.52 mol and 11.04 g of sodium metal = 93 mol percent OH groups were, as described in Example 1, dissolved at 130 to 150 ^° C. in a stream of _{N 2.} The solution, which turned dark brown after the addition of the first portions of sodium, was whitened with further addition of sodium under the action of the nascent hydrogen, and the result was an only vigorously wine-yellow solution, which after the addition of 175 g of ethylene oxide = 7.7 mol of AeO resulted in an iodine- FZ 3.5 resulted, which bleaches with hydrogen peroxide on Jcd-FZ 2, iieß. The key figures and the resulting »sales of the CO group are shown in the next table:

Table example

Oxalylate

Starting alcohol

after

Nb treatment
(calculated values)

Start alcohol diff.

% Sales of the CO group
after

OHZ increase

COZ acceptance

OH number 122.4
CO number 0.0

339.0
0.0

294.5 46.2 + 44.5
- 46.2

96.2

96.5 *)

·) According to the CO number 0.0 found in the oxethylate, a 100% conversion of the CO group in column 6 would be calculated; found it However, there are still small amounts of ketones in the water collected during the drying of the neutralized product, including their inclusion the balance shows the somewhat lower turnover value, which however better corresponds to the increase in the OH number found.

Example 4

Here the conversion and thereby indirectly also the oxyalkylation of a defined ketone, which was added to the starting alcohol in a known amount, shown.

38.3 g sec. Alcohol (OHZ 257.8; COZ 14.5) were mixed with 15.0 g of decyl methyl ketone (OHZ 8.2; COZ 280) mixed and analyzed before use. It was found:

OHZ 188.4

COZ 89.6

a) 53.3 g of the mixture were, as described in Example 1, with 4.6 g of sodium metal = 111.7 mol percent OH groups converted into the alcoholate.

The amount of sodium, which is more than 10% above the OHZ equivalence, is required to achieve sufficient To develop amounts of nascent hydrogen to reduce the CO groups and to convert into the corresponding alcoholates.

The amount of 111.7% Na used is considerably higher than the maximum permissible ratio of 1.05 equivalents of sodium / OH indicated in US Pat. No. 2,782,240.
As in Example 2, the batch was first worked up after exposure to Na without oxyethylation and the CO conversion was checked in the usual way on the basis of the change in OH and CO numbers.

Table example 4a

Starting alcohol after Na treatment
(found values)

% Turnover of the CO group c
after

OHZ attachment

COZ acceptance

OH number 265.0
CO number 3.6

85.5

96.0

b) From the same mixture of sec-alcohol and decyl methyl ketone were

106.6 g alcohol mixture with

9.2 g of sodium metal = 111.7 mol percentage of OH groups and 209.0 g of ethylene oxide implemented.

Table Example 4 b

Oxethylal

OH number 88.9
CO number 2.55

Starting alcohol

after

Na treatment (calculated values)

263
7.55

Starting alcohol

+ 74.6
-82.05

% Of sales Her CO-Gruppe after

OHZ increase

83.3

COZ acceptance

91.6

Example 5

In the same way as described in Example 2, 100 g of secondary alcohol with a molecular weight of 256 reacted with 13.9 g of potassium metal (= 90 mol percent OH groups) and thereby converted into the corresponding Converted alcoholate. After the neutralization has taken place, those are shown in the table below Numbers found.

Table example 5

OH number
CO number

Starting alcohol

222
30.6

Starting alcohol

after

K treatment (found values)

249
2.6

Diff.

+ 27
-28

% Sales of the CO group after

OHZ increase

88.2

COZ acceptance

91.8

In the next examples, those previously used successfully by the process according to the invention are used Starting materials with those used in oxyalkylation chemistry instead of sodium metal common alkalis such as sodium hydroxide or sodium methylate.

Example 6
(Comparison)

The ketone-rich alcohol fraction (OHZ 294.5; COZ 46.2) used in Example 3 should be mixed with sodium methylate be converted into the corresponding alcoholate. One of that in Example 3 was added Sodium metal equivalent amount used, on the one hand to obtain comparable values and on the other hand, because the secondary alcohol groups are only sufficiently activated when the alcoholate is largely formed to give useful oxethylates as end products.

Soon after distilling off the solvent methanol - was used Na content about a 30% methanolic sodium methylate solution at 12.8% - and reaching the reaction temperature of 150 ⁰ C in an oil pump vacuum (about 2 Torr) was approach increasingly strong dark and resin-like solid, so that the stirrer got stuck and it was not possible to continue the experiment. A complete resinification has therefore occurred as a result of alkaline condensation of the carbonyl compounds.

Example 7
(Comparison)

When using NaOH (80 mol percent, based on OH groups) instead of sodium methylate occurs in the case of one which is also strongly enriched with ketones by distillation of the secondary alcohol Alcohol fraction does not include the severe gumming observed in Example 6, and the experiment could be terminated. Without subsequent Äthylenoxydanlagerung the approach was after Alcoholate formation worked up as usual and the kemi numbers determined:

Starting product OHZ 275.6, COZ 37.1

After the NaOH treatment .... OHZ 268.8, COZ 0.0. SZ: 21.8!

The CO number has indeed disappeared; but no conversion into hydroxyl groups has taken place, as happens when using sodium metal. What is noteworthy, however, is the occurrence of a considerable acid number, which one must probably imagine after the known reaction, according to which _{carboxylic acids can be formed from alcohols by the action of strong alkali at high temperature with elimination of H 2} (see Houben-Weyl, vol VIII, p. 404 [1952]: original works by J.Dumas, JA Stas, A. eh. [2]. 73, 113 [1840], and A. 35, 129 [1840]).

example
(Comparison)

The secondary alcohol (OHZ 219; COZ 29.5) used in Examples 1 and 2 was reacted in a so-called two-stage process according to German Patent 974 767 in the first stage with BF ₃ as the acidic catalyst with 1.5 mol of AeO, after neutralization and washing out small amounts of polyglycol, the unchanged starting alcohol is distilled off and the remaining oxyethylate is made alkaline with 3 mol percent AeO (about 50% of the alcohol used was distilled off unchanged) with sodium methylate solution. A strong dark color immediately appeared, which after the addition of a further 6 moles of ethylene oxide in the second alkaline oxyetherification stage lightened somewhat (dilution effect!), But only led to an end product with an iodine color number of 20. Even vigorous bleaching with hydrogen peroxide did not lead to a salable product.

In order to be able to work according to this process, this alcohol containing carbonyl groups would have to be used beforehand only an additional one. Purification by hydrogenation

209 513/390

2153

(ο

IO

be subjected. According to the method of the invention however, it is possible, as Examples 1, 2 and the following have shown, to do this in one step Conversion of the CO groups into OH groups and their oxalkylation to be carried out.

Example 9

An artificially produced mixture of 85 g of iso-C ₁₃ -A'i alcohol and 15 g of iso-C _u -aldehyde, with analytically determined OHN 250.3 and COZ 29.4, was, as described in Example 1 for a secondary alcohol containing ketone, converted into the alcoholate with 9.34 g of sodium metal = 91 mol percent OH groups. The sodium, divided into seven portions, was gradually added over a period of 7 hours; _{Two deep-freeze reservoirs filled with CO 2} snow and acetone were connected to the exhaust gas capillary in order to avoid any loss of volatile aldehydes. The batch was worked up and the key figures determined without subsequent oxyalkylation.

Table example 9

Starting alcohol

after

Na treatment
(found throws)

267

1.35

Starting alcohol

250.3
29.4

DiIT. % Sales volume
of the CO group
after COZ-
acceptance OHZ-
rise -H 6.7 56.7 94.4 -28.05 -

Example 10 (compared to 9)

Of a mixture of 105.0 g Iso-C _ir alcohol and 45.0 g iso-C ₁₃ aldehyde with the key figures OHN 231, COZ 60.4 and SZ 4.1 130 g of powdered with 20.8 g NaOH = 97 mol percent OH groups converted into the alcoholate with nitrogen flushing, then worked up without oxyethylation and the key figures determined.

Table example 10

OH number
CO number
Acid number

Starting alcohol

after

NaOH treatment
(found values)

230.5

0.0
29.0

Starting alcohol Difr. % Sales of the CO group OHZ increase COZ acceptance 11! after _ ) 231 unchanged - 100 60.4 60.4 - - 4.0 25.0

In both cases (Examples 9 and 10) the CO number has practically disappeared; H. the alcohol contains almost no more aldehydes. However, as shown in Comparative Example 10, the treatment with sodium hydroxide there is no increase in the OH number, but organic acids have formed, which is also undesirable. In contrast, when sodium metal is used (Example 9), no new formation of acid occurs. The aldehyde is in this case largely converted into alcohol.

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Claims (1)

Claim: Process for the production of polyglycol ethers by reacting primary and secondary alcohols with 8 to 22 carbon atoms in the Chain with alkali metals, further reaction of the reaction mixture with alkylene oxides and the usual Reconditioning, characterized that the starting materials used are aldehyde- and ketone-containing primary and secondary alcohols used.