CS269926B1

CS269926B1 - Method of metacrylic acid's and ethylene diglycol's 2-hydroxyethoxyester continuous separation

Info

Publication number: CS269926B1
Application number: CS877612A
Authority: CS
Inventors: Ales Ing Csc Heyberger; Vaclav Ing Csc Vesely; Jaroslav Doc Ing Csc Prochazka; Jan Ing Drsc Cermak; Milan Ing Ecsc Rylek
Original assignee: Heyberger Ales; Vesely Vaclav; Prochazka Jaroslav; Cermak Jan; Milan Ing Ecsc Rylek
Priority date: 1987-10-22
Filing date: 1987-10-22
Publication date: 1990-05-14
Also published as: CS761287A1

Abstract

Způsob kontinuálního dělení 2-hydroxyetylesteru kyseliny metakrylové a etylendiglykolu,' jejichž vodný roztok obsahující další vodorozpustné látky vzniká při katalytické reesterifikaci metylesteru kyseliny metakrylové etylendiglykolem a následné rafinaci vzniklé reakění směsi extrakcí alkany. Podle tohoto způsobu se vodný roztok po rafinaci alkany uvádí v intenzivní protiproudý styk s kyslíkatým organickým rozpouštědlem, např. eterem nebo vyšším ketonem, s výhodou metylisobutylketonem, za pomoci vibrací. Vzniklý extrakt, obsahující 2-hydroxyetylester kyseliny metakrylové a malé množství etylendiglykolu a dalších vodorozpustných látek, se uvádí do intenzivního protiproudého styku s čistou vodou za pomoci vibrací a vzniklá vodná fáze, obsahující zbytky etylendiglykolu a dalších vodorozpustných látek se spojí s původním vodným roztokem 2-hydroxyetylesteru kyseliny metakrylové a etylendiglykolu.A method of continuously separating a 2-hydroxyethyl ester methacrylic acid and ethylendiglycol, the aqueous solution thereof containing other water-soluble substances are formed in the catalytic reesterification of the methyl ester methacrylic acid with ethylenediglycol and then refining the resulting mixture extracting alkanes. According to this method the aqueous solution is refined after refining the alkanes v intense countercurrent contact with oxygen an organic solvent such as ether or a higher ketone, preferably methyl isobutyl ketone, with vibration. Vzniklý extract containing 2-hydroxyethyl ester methacrylic acid and a small amount of ethylenediglycol and other water-soluble ones substances is introduced into intensive countercurrent contact with clean water using vibration and the resulting aqueous phase containing residues ethylendiglycol and other water-soluble ones substances are combined with the original aqueous solution Methacrylic acid 2-hydroxyethyl ester and ethylendiglycol.

Description

EN 269 926 B1 1

BACKGROUND OF THE INVENTION The present invention relates to a process for the continuous separation of 2-hydroxyethoxyethyl methacrylate.

takryl formula I ch2 = c-cooch2-ch2-o-ch2-ch2-oh (I)

and ethylenediglycol, the aqueous solution of which is produced during the preparation of compound (I) by re-esterification of methacrylic acid methyl ester with ethylenediglycol under the action of catalysts after refining the reaction mixture by extraction with alkanes. Re-esterification catalysts are alkali metal alcoholates or quaternary ammonium bases. Extraction of the alkanes removes unreacted methacrylic acid ethyl ester from the reaction mixture and most of the by-product diester of formula II

ch2 = c-cooch2-ch2och2-ch2ooc-c- = ch2 (II)

Refining by countercurrent extraction of alkanes with the help of vibrations is the subject of MS. No. 253,632, according to which the aqueous reaction mixture, after extraction with alkanes, is subjected to countercurrent extraction with a solvent of the ester or ketone type or, for example, with diethyl ether, by vibration in which the monoester of formula I becomes a solvent and most of ethylene glycol and diester II remains in the aqueous phase.

The main drawback of the described process for dividing the monoester of formula I from ethylenediglycol and diester residues of formula II is insufficiently sharp, since more than 10% of monoester I remains in the aqueous phase and monoester I, i.e., monoester I is obtained after separation of the solvent from the organic phase. the product contains about 5% of ethylenediglycol and still about 0.55% of diester II. Consequently, considerable losses of monoester I in the aqueous phase are produced and the product containing the ethylenediglycol is insufficiently pure, especially for medical purposes. Another disadvantage of the above method is that the etheric solvents form explosive peroxides and their vapors with the explosive air in contact with the atmosphere. Lower eters are then quite soluble in water, so heat energy needs to be spent to distill them off the aqueous phase after extraction.

These drawbacks have been largely eliminated by the process of separating the 2-hydroxyethoxyethyl methacrylic acid ester of ethylendiglycol according to the present invention. The process comprises the step of intensively contacting the aqueous solution of monoester I and ethylenediglycol, which optionally contains diester II and methanol residues, with oxygen-containing organic solvents such as ethers and ketones, with the preference for, e.g. with methyl isobutyl ketone, by vibration, whereby a solution of monoester I and a small amount of ethylenediglycol, diester II and optionally other water-soluble substances in the organic solvent (extract) is brought into intensive countercurrent contact with a small amount of water by vibration. The resulting ethylenediglycol-containing aqueous phase and other water-soluble substances are combined with the original aqueous solution of monoester I and ethylenediglycol to be separated. In this case, the volume flow ratio of the original aqueous solution of the organic solvent is 1: 1 to 1: 4, preferably 1: 1.5, the ratio of volume flow of water to extract is 1: 7 to 1:14, preferably 1:10.

The process of the present invention makes it possible to achieve, at sufficiently effective countercurrent contact, the high purity phases of the final product, 2-hydroxyethoxyethyl methacrylate, while ensuring its low losses in the outgoing aqueous solution of ethyl endiglycol and other impurities. The use of solvents such as methyl isobutyl ketone reduces the risk of explosion to a large extent compared to solvents of the low-boiling type. Also, the water solubility of higher ketones is low.

Further details of the process according to the invention are given in the following examples, which are not to be construed as limiting the invention.

Claims

1. A process for continuously separating methacrylic acid-ethylene-diglycol 2-hydroxyethoxyethyl ester, the aqueous solution of which still contains diester and ethylenediglycol residues and other water-soluble impurities, is produced by the production of methacrylic acid 2-hydroxyethoxyethyl ester by catalytic re-esterification of methacrylic acid methyl ester with ethylenedi glycol and subsequent refining of the reaction mixture by extraction with alkanes characterized in that the aqueous solution of 2-hydroxyethoxyethyl methacrylic acid and ethylenediglycol esters is vigorously counteracted with oxygenated organic solvent by vibration, the resulting solution of 2-hydroxyethoxyethyl methacrylic acid and other water-soluble substances in the oxygenated organic solvent being intensified countercurrent contact with water by vibration, whereupon the resulting aqueous phase is combined with the original aqueous solution of methacrylic acid 2-hydroxyethoxyethyl ester and ethylenedi glycol.

2. A process according to claim 1, wherein the oxygenated organic solvent is a higher molecular weight ketone, preferably methylsobutyl ketone.

Example 1 5 liters of re-esterification reaction mixture containing 48 wt. % of the compound of formula I, 70 wt. of diester of formula II, 5.8 wt. methyl methacrylate, 26.3 wt. of ethylenediglycol was diluted with 3 liters of water, cooled to 20 ° C and countercurrent extracted with hexane at a volume flow ratio of 1: 1.4. The obtained aqueous raffinate, which contained less than 0.06 wt. of diester of formula II, 18.2 wt. of an ester of formula I and 10.2 wt. Ethylenediglycol was subjected to further extraction with deitylether at a volume flow ratio of 1: 1.5, while the extract was countercurrently washed with water at a flow rate of 10: 1. The extract was concentrated on a vacuum film evaporator. The resulting methacrylic acid 2-hydroxyethoxymethyl ester of formula I contained 0.15 wt. of diester of formula II and 0.4 wt. ethylendiglycol. All three extraction steps were performed on a countercurrent extraction column with vibrating trays. EXAMPLE 2 5 liters of the re-esterification reaction mixture having the same composition as in Example 1 were diluted with 3 liters of water and cooled to 20 DEG C. The reaction mixture thus treated was extracted with petroleum ether at a flow rate of 1: 1.5. . The obtained aqueous raffinate contained 0.06% wt. of diester of formula II, 17.5 wt. of an ester of formula I and 10.2 wt. ethylendiglycol. This raffinate was subjected to extraction with methyl isobutyl ketone in a 1: 2 volume flow ratio, while the methyl isobutyl ketone extract was run in countercurrent with 10: 1 v / v water in parallel in the top of the column. The extract obtained was again concentrated on a vacuum film evaporator. The resulting product 2-hydroxyethoxyethyl methacrylic acid of formula I contained 0.12 wt%. of diester of formula II and 0.3 wt. ethylendiglycol. All extractions were performed on a countercurrent vibration-jet extraction column. SUBJECT MATTER

3. The process of claims 1 and 2, wherein the ratio of the volume flow rate of the aqueous solution to the organic solvent is 1: 1 to 1: 1.4, preferably 1: 1.5, and the ratio of volume flow rates of water to extract is 1: 7 to 1:14, preferably 1:10.