DE2020118A1 - Process for the preparation of epoxyalkyl esters - Google Patents

Description

Description of the patent application

SiIELLIHTERNATIONALERESEARGHMAATSCHAPPIJN-V., 3O ₁ Carel van Bylandtlaan, The Hague / Netherlands

concerning:
"Process for the preparation of epoxyalkyl esters"

The invention relates to a process for the preparation of epoxyalkyl esters of carboxylic acids with one or more Carboxyl groups per molecule by reacting an alkali metal salt of the carboxylic acid with more than the stoichiometry '.' Amount of an epoxy monohaloalkane whose halogen atom is adjacent to the epoxy group.

In order to limit undesired secondary and secondary reactions in these processes, the desired reaction is preferably carried out in a medium which contains no water or only a very small amount of water. So far ', this has been achieved _{t n} that emanated from alkali metal salts of carboxylic acids, which had been carefully prior to the reaction with the Epoxyhalogenalican'getrocknet. The removal of the last traces of water from the salt, however, is difficult to carry out and requires complex processes such as spray drying. ■

Aue of British Patent A 056 986 is one method

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known for the preparation of an epoxyalkyl ester of a monocarboxylic acid, this separate upstream step of Saiztrocknens is avoided in that the epoxyhalogenoalkane is heated with a salt of this acid in the form of a suspension in an organic solvent, this suspension by gradually adding an aqueous. Alkali metal hydroxide solution to a solution of the monocarboxylic acid in the organic solvent and distilling off the water had been obtained. The preferred solvents in this process are hydrocarbons, especially those that ψ can be azeotropically distilled together with water. However, no values are reported about the water content of the salt suspension at the time when the epoxyhalogenoalkane is added.

The invention is concerned with a simpler and more effective one Process whereby not only the reaction of the salt with the epoxyhalogenoalkane in an almost anhydrous iledium without drying of the salt is carried out prior to contact with the epoxyhaloalkane, but also not organic Solvent during salt formation and during the reaction is used.

The process according to the invention for the preparation of epoxyalkyl esters of carboxylic acids with one or more carboxyl groups in the molecule by reacting an alkali metal salt of the carboxylic acid with 'more than the stoichiometric amount of an epoxy monohalogen alkane, the hemogen atom of which is the epoxy group is adjacent, in the presence of a catalyst, is characterized in that one behind the other

(a) gradually an aqueous alkali metal hydroxide solution a concentration of at least 20 wt .- ^ to one sie.den.den mixture containing the carboxylic acid or its Contains anhydride as well as the epoxyhaloalkane, at one

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Adding temperature below 1OQ ⁰ C with simultaneous distilling off water and Epoxyhalogenalkan;

(b) the distillation last at a temperature which _; . higher than the temperature of the boiling mixture during the alkali metal hydroxide addition, at least as long

- until the water content of the mixture is below -0.5 % by weight, preferably below 0.1% by weight;

(c) adding the catalyst and

(d) hitzt the mixture at a temperature of at least 50 ⁰ C ER- ■. ■■■■■ ' ^: -

The preferred temperature of the boiling mixture during the addition of the alkali metal hydroxides (step a) is between 50 and; 7O ⁰ C, which generally means that it is carried under reduced pressure.

Usually during the addition, the alkali metal hydroxide will be added the distilled water and das'Epoxyhalogenalkan condensed and caught in an oaiaaler, from which the separated Epoxyhalogenalkane is recycled into the boiling mixture.

The temperature at which the distillation is carried out (stage b) is preferably selected to be 110 and 130 G, including in general a pressure increase to at least atmospheric pressure is required. Usually these conditions do not change applied until there is a noticeable further decrease in water content of the reaction mixture. it is no longer noticed.

To as much as possible during the addition of the aqueous Alkali ^ ietalliivdroxxdlösung and the water added during the adjacent salt formation to remove water formed and / or the hydroxyhalogen alkali concentration at which the

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When catalytic ester formation is carried out, it may be desirable to add fresh epoxyhaloalkane to each of stages a through d, preferably no earlier than the start of stage b and no later than the start of stage d. Most preferred is the addition of the fresh epoxyhaloalkane during step b and continuing the distillation until the epoxyihaloalkane concentration at which catalytic ester formation is started is reached. This eliminates the need to handle a large volume of the boiling mixture when starting supposed to bring the mixture to the boil. The addition of fresh epoxyhalogenoalkane V when the distillation temperature is increased or immediately before this point is an effective measure for further reducing the water content.

Of the epoxyhaloalkanes used in accordance with the invention, epoxy-fluorine is preferred. However, other Epoxyhalogenalkan® _ß such as epibromohydrin, 2-methylepichlorohydrin, 1-chloro-2,5-epoi-butane and 1-chloro-2 _f 3-epoxyhexane can be used.

The preferred alkali metal hydroxide to be added to the boiling mixture is potassium hydroxide. A gradual addition of the alkali metal hydroxide is required to have a strong Heat build-up and a sudden, intermittent sharpness Avoid increasing the wa & s & rk & naeatration. The rate of addition the byaroxide solution can be higher if the concentration of this solution, the stirring speed and the amount of steam generated per tedding unit is selected in this way that they are higher, the speed of addition of the Hydroxide can easily be adapted to the other conditions. In addition, the length of time required for the addition is necessary is, longer, wsihi the amounts of the raw materials used large · siad · Most of the time, the encore takes place within a period of at least a quarter of an hour, • vo2? EUgBwaist® if; @ nig8fe © as half an hour give g «B. from "

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one to several hours.

In order to keep the amount of water introduced with the alkali metal hydroxide solution relatively low, the concentration of the hydroxide is preferably adjusted to at least 45 % by weight , the highest possible concentration being most favorable. For the same purpose, it is desirable that the boiling mixture to which the concentrated alkali metal hydroxide solution is to be added contain its anhydride instead of the carboxylic acid. It is therefore particularly preferred to combine these three measures. The carboxylic acid or anhydride may be dissolved or dispersed in the epoxyhaloalkane, the state of the solution being the most effective.

The preferred amount of alkali metal hydroxide is from 0.8 to 1.2 times the equivalent amount, with amounts im Range from 0.95 to 1.05 times the equivalent amount are particularly preferred.

Although the invention is the preparation of epoxyalkyl esters of carboxylic acids in general, including monocarboxylic acids, are epoxyalkyl esters according to the invention of carboxylic acids with at least two carboxyl groups especially aimed at. Another preferred feature of the Carboxylic acids is the presence of a ring of at least 5 carbon atoms in the ring, especially if at least two carboxyl groups bonded directly to this ring are. In particular, cycloaliphatic rings are desirable. Furthermore, the rings of the carboxylic acids are preferably six-membered rings, with the most preferred Representatives of such compounds are the hydroforthophthalic acids, such as tetra-hydrophthalic acid and especially hexahydrophthalic acid.

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As already mentioned, the amount of epoxy monohaloalkane, with which the alkali metal salt is to be reacted, higher than the stoichiometric amount. If-the catalyst is added, the ratio corresponds to the epoxyhaloalkane compound sum alkali metal salt more than 1.5 gram atoms Halogen per gram atom of alkali metal, where a ratio corresponding to 4 to 10 gram atoms of halogen per gram atom Alkali metal is particularly preferred. When the desired low water content of the reaction mixture is reached, however, the ratio of epoxyhalogenoalkane to salt is still too high, this ratio can be adjusted to the desired one Ratio can be lowered by further continuation of the distillation. In the case when the ratio is epoxyhaloalkane To SaIa is too low, when the desired low water content is reached, fresh epoxyhaloalkane can be used immediately bar before, during or immediately after the addition of the catalyst be added.

The preferred catalysts used in the invention are quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, Tetrabutylaramoniumchlorid, benzyltrimethylammonium _T Benzyltrimethylammoniumsulfat, Cyclohexyltrimethylaannoniumbronia, Phenyltrioctylanimoniumchlorid and Diphenyldijäethylaramoniumborat. However, tertiary amines such as triethylamine, triphenylamine odei ^ tricyclohexylamine and also thioethers and / or their sulfoaium salts, phosphines such as triphenylphosphine or phosphonium salts can be used as suitable catalysts.

The final stage (d) of the process, wherein the Genisch is heated to a temperature of at least 50 ⁰ C after the catalyst addition is preferably carried out at a temperature of at least 100 ⁰ ■ C. As a rule, this heating is continued until the ester formation is complete.

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Usually the heating takes place under reflux.

The invention is further illustrated by the following examples explained »

B e i 8 ρ i e 1 1

There were 154 g (1 mole) of hexahydrophthalic anhydride (HHPA) in 1110 g (12 mol) of epichlorohydrin (ECH) was dissolved, then the solution was boiled at a reduced pressure of 100 mm Hg and reflux and the boiling temperature under these conditions is about 6O ⁰ C was. An amount of 221.3 g of a 50.6-Ge ^ .-% aqueous potassium hydroxide solution was gradually added to the boiling mixture over the course of 2 hours, while the water was distilled off as an azeotrope with EGH and was collected in a collector which was in the Backflow system was built in. From this collector, the condensed ECH that formed the lower layer was returned to the boiling mixture, while the upper layer of water was left in the collector.

After the potassium hydroxide was added, an additional amount of water was removed by distilling off the ECH without the use of reflux. For this purpose about 40 # of the ECH was first distilled off at the said reduced pressure and then an amount of fresh ECH corresponding to about 100 % of the original amount of ECH was added and finally an amount corresponding to about 60 % of the original amount was distilled off at atmospheric pressure. As a result of this comparison · drive, the temperature rose at the bottom of the distillation flask to approximately 116 ° C and the water content of the mixture had dropped to eiedenden O ₁ Oj weight yi. Thereafter, 3 g of letramethylanehapniulibromide were added, after which the mixture was 2 hours. aa was refluxed. During this period the soil temperature rose to 120 ° C. Eventually it became the reaction product

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isolated by successively (1) 90 to 95 % of the unreacted Epiehlorhydrin at a pressure of 15 to 25 mm Hg (bottom temperature at most 70 ⁰ G) was distilled off, (2) toluene was added at atmospheric pressure until an ester solution of about 25 _e -% was obtained, (3) the mixture was ^{cooled to a temperature below 30 °} C., (4) the mixture was washed once with water and twice with a 5% by weight aqueous solution of NaHgPO ^, (5 ) the toluene was distilled off and (6) the product was ^{heated at 140 °} C. for 1 h.

"The results are shown in the table, which is also. reproduces the results from the following examples.

B ei ρ J ₁ e. I _n e 2 __ to _6

There were in the same Weiee wi® in Example 1 further Ver. The search was carried out but there were some differences which, along with the results obtained, are shown in the following table.

TABEL :

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■■ ■ ■. ■■ ■■ .., -.- _Γ 9V .... ■ '

TABEL

Example no. 1 2 3 4

Molar ratio

ECH / HHPA 12 12 12 12 12 12

KOH / HHPA 2.00 2.05 2.05 2.05 2.05 2.10

KOH solution

Concentration, wt -.% 50.6 51.5 50.6 50.6 50.6 51.5 addition amount, g 221.3 223.0 227.9 227.0 227.0 229, Ο

H ₂ O content

of the boiling ge.

mix immediately
before addition of the catalyst, wt .-% 0.03 0.15 0.22 0.1 0.05 0.24

Reaction conditions

(after addition of catalyst) time, h 2 1.5 2 3 4-, 5 2 temperature, ⁰ C 116-115- 115- 115- 115- 115-

120 118 118 118 119 118

Analytical values of the glycidyl ester

Epoxy equivalent 165 165 164 165 178 164 viscosity

(Stokes), 25 ⁰ C 3.2 3.0 3.7 3.0 5 »5 3.5 Color (Gardner) 4 3-4 4-5 4-5 7-8 4-5

Saponification content

baremic chlorine,% w / w 1.311.60 0.75 1.43 1.80 0.95 Total chlorine, wt% - 1.93 x 1.12 1.76 4.09 1.36

Yield \ fo .

(based on HHPA) 93.1 90.7 91.8 94.2 98.5 92.5

PATENT CLAIMS:

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ORIGINAHNSPECTED

Claims (1)

1A-37 708 - 10 PATENT CLAIMS Process for the preparation of epoxyalkyl esters of Carboxylic acids with one or more carboxyl groups per molecule by reacting an alkali metal salt of the carboxylic acid with more than the stoichiometric amount of an epoxymonohalogenalkane, whose halogen atom is adjacent to the epoxy group »in the presence of a catalyst, characterized in that one behind the other (a) an aqueous Alkalimetallhydroxidlosung gradually, adding a concentration of at least 20 wt .-% to a boiling mixture containing the carboxylic acid or its anhydride and the Epoxyhalogenalkan at a temperature below 100 ⁰ C with simultaneous distilling off "water and Epoxyhalogenalkan; (b) the distillation last at a temperature higher than the temperature of the boiling mixture during the The addition of alkali metal hydroxide is at least continued until the water content of the mixture is below 0.5% by weight, preferably below 0. T% by weight; (c). adding the catalyst and (d) heating the mixture at a temperature of at least 5O ⁰ C. ". 2) Process according to claim 1, characterized in that the temperature of the boiling mixture during stage (a) is between 50 and 70 ^° C. 3) Method according to claim 1 or 2, characterized in that g e k e η η shows that the eventual distillation O
temperature is between 110 and 130 C. - 11 00 9846 / 1t93 bath 1A-37 708 - 11 - 4) Method according to claim 1 to 3, characterized g e k e η η ze i c h η e t that one during ^ eder der Steps (a) to (d) fresh epoxyhaloalkane to which the Alkali metal salt-containing mixture is added. 5) Method according to claim 4, characterized in that g e k e η. η ζ e i c h η e t that the fresh epoxyhaloalkane v / uring stage (b) is added and the distillation continues until the epoxyhalogenalkane concentration, at which begins the catalytic ester formation is reached. 6) Process according to claim 1 Me 5 »characterized in that the epoxyhaloalkane is spichlorohydrin used. 7) Method according to claim 1 to 6, characterized in that g e k β η η ζ ei c h η e t that nan as an alkali metal hydroxide Potassium hydroxide used. 8) Method according to claim 1 to 7 ν characterized ge characterized in that the carboxylic acid used is fletrahydrophthalic acid or hexahydrophthalic acid. . 9) A method according to claim 1 to 8, characterized _f in that the concentration of the aqueous alkaline ta llhydroxidlö solution which sugeeetst in step (a) "is at least 45 wt -.% By and öaß daa boiling Genieofc" in anhydride of Carboneäure contains. .10) Method according to claim 1 to 9 »characterized that the amount of the added alkali tallhydroxids 0.8 to 1.2 times the equivalent amount amounts to. Ii) Method according to claim 10, characterized in that g e k e na - 1993 " ^T " BADQfflGlNAL 1A-37 708 - 12 - records that the amount of added alkali metal hydroxide 0.95 "to 1.05 times the equivalent Amount is. 12) Method according to claim 1 to 11, characterized in that the water is distilled off as long as until at least the water content of the reaction mixture is below 0.1% by weight. 15) The method of claim 1 to 12, characterized in that the catalyst used is a quaternary ammonium salt w. 14) Method according to claim 1 to 13, characterized in that the ratio of epoxyhaloalkane to the alkali metal salt when adding the catalyst more than 1.5 gramo atoms of halogen per gram atom of alkali metal amounts to. 15) Method according to claim 14, characterized ι that the ratio of epoxyhalogenalkane to alkali metal salt when the catalyst is added 4 to 10 gram atoms of halogen per gram atom of alkali metal. 009846/1993 BATH ORIGINAL