DE1157623B - Process for the preparation of ethylene glycol monoesters of saturated carboxylic acids - Google Patents

Description

GERMAN

PATENT OFFICE

C24564IVb / 12o

REGISTRATION DATE: JULY 8, 1961

NOTICE THE REGISTRATION AND ISSUE OF THE EDITORIAL: NOVEMBER 21, 1963

_ Be ο After patent application C 23852 IVb / 12 Äthylenglykolmonoester saturated carboxylic acids made by reacting saturated mono- or polycarboxylic acids, alone or in mixture with one another with ethylene oxide, optionally in excess, at temperatures between 25 and 200 ⁰ C, preferably between 80 and 16O ⁰ C, in the absence of catalysts and in the presence of a mixture of water and amides of saturated low molecular weight aliphatic carboxylic acids or their N-alkylation products.

Compared to the known method of esterification or transesterification of terephthalic acid or monomethyl terephthalate in the presence of basic catalysts, the yields are comparative when using the process of the main patent application when using terephthalic acid at 84% of theory and when using other feedstock, such as terephthalic acid monomethyl ester, at about 95% and in some cases even over 98% of theory. According to known processes, yields between 35.4 and 67.8% of theory obtained with a reaction time of 11 to 20 hours, and the acid used is obtained only partially implemented. The alkali salt of the monoglycol ester present at the same time makes recrystallization more difficult and filtration, which affects the purity of the final product as it comes out of the Melting point can be seen.

Examples of saturated mono- or polycarboxylic acids are the aliphatic carboxylic acids with 1 to 20 carbon atoms, benzenecarboxylic acids, their monoalkyl esters, core halogen substitution products, Core alkyl substitution products, products containing hydroxyl groups and chloroalkyl substitution products, Phthalic acids, tri- and tetrabenzenecarboxylic acids, naphthalic acid in question.

The carboxylic acids mentioned can not only be used in their purest form, but it is also possible to use technical carboxylic acids.

The saturated low molecular weight aliphatic carboxamides or N-alkylation products are used for example formamide, dimethylformamide or dimethylacetamide in question.

Low-pressure autoclaves or boilers are suitable as reaction vessels Allow pressure from 0 to 15atü. The vessels should expediently have a filler neck, gas inlet and outlet pipe and a stirring device. The choice of vessel material depends on the corrosive Property of the carboxylic acids; it should be a good quality steel.

It has now been found that in the production process for production

of ethylene glycol monoesters more saturated

Carboxylic acids

Addition to patent application C 23852 IVb / 12 ο
(Interpretation 1154 479)

Applicant:

Chemical works in Witten

Company with limited liability,

Witten, Arthur-Imhausen-Str. 92 a

Dipl.-Chem. Ewald Katzschmann,

Dortmund-Kruckel,
has been named as the inventor

from ethylene glycol monoesters to saturated carboxylic acids according to the method described in patent application C 23852 IVb / 12 ο, the reaction rate increase considerably and possibly the amount of amide to be used considerably can reduce and get to end products with an extremely low acid number, if you the mixture of carboxylic acid and the mixture of water and amides neutral inorganic alkali salts, preferably chlorides and / or nitrates and / or sulfates, in amounts up to 10%> based on the carboxylic acids used.

As neutral inorganic alkali salts, the potassium salts, in particular Potassium chloride, can be used.

Possible carboxylic acids are those mentioned in patent application C 23852 IVb / 12 ο.

Instead of the inorganic alkali salts suitable according to the invention, the corresponding Alkaline earth salts are used insofar as they are water-soluble and in the reaction with the carboxylic acids do not provide sparingly soluble salts.

The products which can be prepared by the process according to the invention are valuable intermediates for the manufacture of plasticizers, resins and paints. The esters of polybasic carboxylic acids, such as B. Terephthalic acid di- [ethylene glycol monoester], are without a catalyst only by heating to 200 to

309 749/430

300 ° C polycondensable. They deliver well-defined ones high molecular weight plastics or fiber raw materials.

The ratio of water to amide up to 50: 1 provides in the presence of the neutral compounds mentioned according to the invention Alkali salts excellent results, which can be clearly seen from the following examples.

example 1

A mixture of 148 g of propionic acid, 250 g of ice water, 100 g of dimethylformamide and 132 g of ethylene oxide was heated in a pre-cooled V4A shaken within one hour to 100 ° C and then shaken for a further ¹ hour _J2 without further heating. The reaction product (626 g) has an acid number of 29. This corresponds to 24 g of unreacted propionic acid.

If you work in exactly the same way, only with the addition of 2 g of sodium chloride, the value is The acid number of the reaction product is only 15. When using 4.5 g of sodium chloride, a final acid number is obtained of 4 achieved. 6 g and more sodium chloride up to 10 percent by weight, calculated on carboxylic acid, leads to a final acid number below 2.

Example 2

A mixture of 122 g of benzoic acid, 250 g water, 100 g of dimethylformamide and 8 g of sodium chloride was heated in a cylindrical vessel at 9O ⁰ C. Ethylene oxide was introduced into the clear solution, which had an acid number of 119, through a distributor ring at a rate of about 0.71 per minute. After 3.5 hours the acid number is 0.3. Extraction of the reaction product with ether and subsequent distillation gave 96% of theory of pure ethylene glycol monoester.

The comparison experiment without the use of sodium chloride still had an acid number after 3.5 hours from 38.

Example 3

A mixture of 176 g of butyric acid, 250 g of water, 100 g of dimethylformamide and 15 g of potassium chloride was, as described in Example 2, treated with ethylene oxide. After 4.5 hours the acid number was 212 dropped to 6.

A comparative experiment without the use of potassium chloride still showed an acid number after 8 hours from 96.

Example 4

A mixture of 166 g of terephthalic acid, 340 g of ice water, 10 g of dimethylformamide, 16 g of sodium chloride and 132 g of ethylene oxide was ^{heated to 120 °} C. within one hour in a pre-cooled V4A shaking autoclave and then ^{shaken for a further 1} l for ₂ hours without heating. The reaction product was ^{a clear solution at 80 °} C. The crystals formed after cooling overnight were filtered off with suction, washed with water and dried. 195 g = 75% of the theory of di- [ethylene glycol monoester] terephthalic acid with an acid number = 3.2 and saponification number = 440 (calculated 443) were obtained. Further amounts are dissolved in the filtrate due to the readily solubility of the ester and can be obtained by evaporation.

The comparative experiment without using sodium chloride gave a pasty at 80 ⁰ C product. The hot water-insoluble fraction was 116 g and had a saponification number of 656. It was practically unchanged terephthalic acid. 42 g of crystals = 16.5% of the theoretical monoglycol ester with an acid number of 24 and a saponification number of 443 could be obtained from the filtrate.

The comparative experiment without dimethylformamide and without sodium chloride yielded 162 g of unchanged terephthalic acid return. Glycol monoester could not be obtained.

Example 5

A mixture of 166 g of terephthalic acid, 340 g of ice water, 10 g of dimethylformamide, 16 g of potassium chloride and 132 g of ethylene oxide was heated in a pre-cooled V4A autoclave within one hour to 12O ⁰ C and then further shaken _V2 hour without heating. The reaction product ^{had a clear solution at 78 °} C. and had an acid number of 1.5. Because of minor mechanical impurities, it was filtered hot and then left to crystallize overnight. 174 g of crude terephthalic acid di- [monoglycol ester] were obtained with the following key figures:

Found Calculated

Acid number 1.8 0

Saponification number 439 442

Chlorine content 0.4% 0

Melting point 110 to Hl ⁰ C

After another recrystallization from water, the key figures were:

Acid number 0.4

Saponification Number 442

Chlorine content 0

Melting point 112 to 113 ° C

The first filtrate was admixed with dilute hydrochloric acid until the Congo acidic reaction occurred. As a precipitate 44 g with a saponification number of 546 were obtained after suctioning off, washing and drying. This Intermediate product was added to another batch.

Example 6

A mixture of 136 g of m-toluic acid, 330 g of water, 20 g of formamide and 10 g of potassium nitrate were heated to 80 ° C. in a cylindrical vessel. After about The acid was dissolved for 40 minutes, while ethylene oxide was about 0.51 per minute through one at the bottom Distribution ring has been initiated. There was now a milky-cloudy product, which when passed through of less ethylene oxide clearly separated into two layers. The course of the reaction was determined by determination of the drop in acid number tracked:

Acid number

hours

71

24

0.8

The unreacted ethylene oxide, which was still in the solution and in the device, was blown out with nitrogen for 10 minutes and recovered via a freezer trap. The reaction product was placed in a separatory funnel for separation. The monoester sets itself apart as an underclass. The lower layer was washed again with water and, after clear separation, still in the P ₂ O ₅ desiccator.

dries. 175 g of water-clear monoester = 97.2% of theory with the following key figures were obtained :

Found Calculated

Acid number 0.5 0

Saponification Number 310 312

The ester is liquid and can be easily operated in an oil pump vacuum distill.

If the reaction is carried out without the addition of potassium nitrate, the acid number is after 4.5 hours of the reaction product still 52, after 8 hours another 16.

Example 7

A mixture of 116 g caproic acid, 250 g water, 25 g of dimethylformamide and 10 g of potassium chloride were, as described in Example 6, treated with ethylene oxide. After about 40 minutes the reaction product was uniform. The following drop in acid number was analytically determined:

Acid number ..

hours

1 2 I 3 i 4

123

78! 42

I.
10 ^! 0.4

The weight increase was 49 g instead of the theoretical 44 g. 308 g of ethylene oxide and thereof were introduced 255 g of ethylene oxide were recovered via a freezer trap placed behind the reaction vessel. That The reaction product separated well in the separatory funnel. The monoester was obtained as an upper class and washed twice more carefully with water. Then the water dissolved in the ester was im Vacuum removed. The aqueous layer and the washing water were extracted with ether. It became through it 21 g of ester were obtained. The total yield was 154 g of ethylene glycol monoester of caproate = 96.3% of theory.

The ester can easily be distilled and passes over at 85 to 88 ^° C. at 1 mm Hg.

Example 8

A mixture of 176 g of butyric acid, 300 g water, 50 g of dimethylacetamide, 10 g of potassium chloride and 5 g of sodium nitrate was treated in a cylindrical vessel at 6O ⁰ C, as described in Example 6 with ethylene oxide. The acid number of the reaction product was only 47 after 8 hours.

Without the addition of potassium chloride and sodium nitrate, the acid number was 127 in the comparative experiment.

Example 9 ₅ -

A mixture of 122 g of benzoic acid, 330 g of water, 20 g of formamide and 10 g of sodium sulfate was in treated with ethylene oxide in a cylindrical vessel at 90 ° C. and otherwise as described in Example 6. The drop in acid number was determined analytically as follows:

The reaction product separated into two layers. The monoester was the lower class. He was washed thoroughly with water and separated clean and the dissolved water removed in vacuo. The yield of monoester was 152 g = 91.6% of theory.

Example 10

A mixture of 148 g of propionic acid, 300 g of ice water, 25 g of dimethylformamide, 30 g anhydrous calcium chloride and 130 g of ethylene oxide was heated in a pre-cooled V4A shaken within an hour to 12O ⁰ C and then shaken without further heating until the temperature on 7O ⁰ C had dropped. The reaction product had an acid number of 6.3. After neutralization of the reaction product with aqueous ammonia solution, it was filtered with the addition of activated charcoal and then extracted with ether. The ether extract obtained was 204 g = 86.5% of theory of propionic acid monoethylene glycol ester.

Example 11

A mixture of 143 g of tetrachlorophthalic anhydride, 300 g of ice water, 50 g of dimethylformamide, 10 g of crystalline magnesium chloride and 120 g of ethylene oxide was heated in a pre-cooled V4A shaken within one hour to 140 ° C and then allowed to cool with agitation to 8O ⁰ C. The reaction product was neutralized with aqueous ammonia solution and extracted with ether. Mechanical separation of the two layers is also possible. In terms of ether extract, 176 g of monoester = 89.7% of theory were obtained. The key figures were:

Calculated

Acid number ..

2 hours 3 4th 5 6th 1 51 30th 15th 10 3 81

Acid number 0.8 0

Saponification Number 284 287

Chlorine content 35.8% 36.2%

Claims (2)

Patent claims: 1. Process for the preparation of ethylene glycol monoesters from saturated carboxylic acids, which can be used alone or in a mixture with one another, with ethylene oxide, optionally in excess, at a temperature between 25 and 200 ° C, preferably 80 to 160 ° C, in the absence of catalysts and in the presence of a mixture of water and amides of saturated low molecular weight aliphatic carboxylic acids or their N-alkylation products according to patent application C23852 IVb / 12o, characterized in that during the reaction neutral inorganic alkali salts, preferably chlorides and / or nitrates and / or sulfates, or neutral inorganic water-soluble alkaline earth salts , which do not give sparingly soluble salts when reacted with the carboxylic acids, are used in amounts of up to 10%> based on the carboxylic acid used. 2. The method according to claim 1, characterized in that the neutral inorganic alkali salt Potassium chloride is used. 0.9 Publications considered:
German Patent Nos. 905 736, 951 865;
Austrian patents No. 163 642, 190 919. © 309 749/430 11.63