EP2768795A1 - Verfahren zur synthese von citronensäureestern - Google Patents
Verfahren zur synthese von citronensäureesternInfo
- Publication number
- EP2768795A1 EP2768795A1 EP12775233.5A EP12775233A EP2768795A1 EP 2768795 A1 EP2768795 A1 EP 2768795A1 EP 12775233 A EP12775233 A EP 12775233A EP 2768795 A1 EP2768795 A1 EP 2768795A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- acid
- citric acid
- mmol
- reaction
- synthesis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/55—Design of synthesis routes, e.g. reducing the use of auxiliary or protecting groups
Definitions
- the present invention relates to the targeted synthesis of citric acid esters.
- Citric acid esters are of industrial interest, as they may i.a. be used as emulsifiers or surfactants. Of particular importance are the monoesters of fatty alcohols, polyethoxylated fatty alcohols and mono- and diglycerides. Such esters are already used in the food industry, in cosmetics and in
- citric acid esters Due to the chemical structure of citric acid, there are two isomeric mono- and diesters of citric acid (see US Pat. No. 4,866,203 and the state of the art cited therein), favorable and efficient syntheses of citric acid esters, in particular mono- and diesters, which are specifically (predominantly) provide only one of the Citronenquipreesterisomeren, but are so far essentially unknown.
- the object thus is a process for the targeted synthesis of
- Citric acid mono- and diesters provide which predominantly provides only one isomer and which is particularly feasible under mild conditions. This object is solved by claim 1 of the present invention. Accordingly, a process for the synthesis of asymmetric mono- and / or symmetrical diesters of citric acid is presented, comprising the step a) reaction of citric acid with alcohol in the presence of boric acid and / or at least one boronic acid.
- asymmetric citric acid monoesters esters which have been esterified to one of the primary carboxylic acid function of citric acid, i.e., in particular have the following structure:
- esters are chiral.
- the racemate or the achievable ee is usually minimal.
- esters which have been esterified on both primary carboxylic acid functions of citric acid, while the tertiary carboxylic acid is unesterified, ie in particular esters of the following structure:
- R and R ' may be the same or different depending on the reaction, also R and R' may form a ring, i. be connected to each other.
- alcohol is not to be understood as restricting that an alcohol mixture can not also be used, which may very well constitute a preferred embodiment of the invention.Also, the term “alcohol” should not be understood to mean that phenols can not be used ,
- boric acid can also be generated from precursors or in situ, e.g. from sodium borohydride or borane / THF. These reagents also react.
- "boric acid” in the sense of the invention means any boron compound which reacts under reaction conditions (alcohol, acid) at least partially to form boric acid or the boron-citric acid complex indicated above
- Preferred boronic acids are (due to their increased stability and availability) arylboronic acids or Heteroarylboronic acids. It has been found that
- electron-rich phenylboronic acids such as, for example, 2,4,6-trimethyl-, 4-methoxy- and 4-dimethylamino-phenylboronic acid are particularly suitable and preferred. Particular preference is thus given to 2,4,6-trimethylphenylboronic acid, 4-methoxyphenylboronic acid and 4-dimethylaminophenylboronic acid and mixtures of these acids.
- boronic acid may also be suitable, analogous to boric acid
- boronic acid in the context of the invention means any boron compound which under reaction conditions (alcohol, acid) at least partially reacts to form a boronic acid or directly to a boronic acid / citric acid complex.
- reaction can of course also with a mixture of boric acid and
- step a) Boronic acid (s) are performed.
- the boric acid and / or the boronic acid is preferably used in step a) in a molar fraction of> 1 to ⁇ 60%, preferably> 5 to ⁇ 40% (in the case of mixtures, the molar fraction refers to the sum of the components).
- This procedure has proven itself in practice, since such a speedy implementation takes place.
- step a) takes place at a temperature of> -20 ° C and ⁇ 100 ° C, preferably> 0 ° C and ⁇ 80 ° C and most preferably at> 15 ° C and ⁇ 30 ° C instead.
- step a) takes place in the presence of a dipolar aprotic solvent, preferably selected from the group consisting of ethyl acetate, tetrahydro-uran, diethyl ether, methyl tert-butyl ether, 1,4-dioxane, ⁇ , ⁇ -dimethylformamide, dimethyl sulfoxide, 1,2-dichloroethane, acetone, ⁇ , ⁇ -dimethylacetamide, dimethoxyethane, still preferably ethyl acetate, tetrahydro-uranium, diethyl ether, methyl tert-butyl ether, 1,4-dioxane, N, N-dimethylformamide, dimethyl sulfoxide, 1, 2-dichloroethane, ⁇ , ⁇ -dimethylacetamide, chlorobenzene, toluene, Dimethoxyethane, hexane
- step a) The duration of the reaction of step a) depends strongly on the temperature used; Usually the reaction is carried out until no further product is formed. The reaction takes place only in the acid, so by addition of base, the reaction can be stopped in a simple manner.
- the preferred ratio of alcohol to citric acid depends on whether specific mono- or diesters are to be synthesized.
- Solvents e.g., chloroform or ethyl acetate / hexane mixtures.
- Citric acid remain as an insoluble residue.
- AAV1 Synthesis of "technical” monoester / diester mixtures without isolation of the
- Heating preferably ⁇ 80 ° C
- Heating preferably ⁇ 80 ° C
- boric acid can also be removed by means of aqueous extraction. This is particularly well achieved by using dilute acids (e.g., 0.1N hydrochloric acid) or a boric acid-complexing agent, e.g. Mannitol is used.
- dilute acids e.g., 0.1N hydrochloric acid
- a boric acid-complexing agent e.g. Mannitol
- This method is particularly suitable for the use of polyethoxylated fatty alcohols.
- AAV2 Synthesis and Isolation of Unsymmetrical Citric Acid Monoesters
- the citric acid (1.5-5 equivalents) is dissolved in a solvent such as THF or acetone.
- the alcohol (1 equivalent) and the boron boronic acid (5-40% based on the citric acid used) are reacted at room temperature or with heating (preferably ⁇ 70 ° C).
- the conversion of alcohol is usually 85-95%.
- the excess citric acid can be recovered (especially when using boric acid).
- the solvent is optionally removed and the product is extracted with a suitable solvent (eg chloroform or
- citric acid and a part of the boric acid then remain as insoluble residue, can be separated and reused.
- the citric acid monoester (crude product) obtained after removal of solvents can be further purified by recrystallization.
- boric acid and citric acid can be removed by aqueous extraction. For this purpose, volatiles are removed in vacuo and then, e.g. Ethyl acetate added. With an aqueous extraction (see AAV1) citric acid and boric acid are removed. After washing (e.g., saturated NaCl solution), drying (e.g.
- the citric acid monoesters (crude products) obtained according to AAV2 can also be used as salts, e.g. as disodium salt.
- a solution of the citric acid monoester is added to a saturated solution of sodium acetate (2 equivalents) in a methanol / acetone mixture. The precipitate is filtered off with suction and dried.
- boronic acid as
- the alcohol (2-10 equivalents), citric acid (1 equivalent) and boron / boronic acid (5-40%, based on the citric acid used) are reacted at room temperature or with heating (preferably ⁇ 80 ° C).
- a solvent which is not absolutely necessary
- tetrahydrofuran or acetone may be added.
- the conversion to the diester can be increased by removing the water of reaction. This is possible, for example, by the addition of magnesium sulfate, in low-volatility alcohols can
- Reaction water can also be removed in vacuo.
- the diester For the purification of the diester (when using boric acid as catalyst), for example, ethyl acetate is added and the boric acid is removed by means of aqueous extraction (see AAV1).
- the crude product is generally still contaminated by monoesters, excess alcohol and possibly also triesters.
- the monoester can often be removed by shaking it out with an aqueous base (in some cases the diester precipitates as a sparingly soluble salt after base addition and can be isolated directly).
- Excess alcohol can also be removed in the vacuum in the case of low-boiling alcohols.
- a chromatographic separation is possible.
- the diester can also be purified by recrystallization. However, in the case of fatty alcohols, the diester then accumulates as an adduct of one equivalent
- Residue was recrystallized from 700 ml of cyclohexane, whereupon 107.9 g (54.8%)
- Citric acid monoesters were obtained as a colorless solid.
- Example 7 Synthesis of Symmetric Citric Acid Dimethyl Ester - Isolation as Monohydrate 50.0 g of anhydrous citric acid (260.2 mmol) and 1.5 g of boric acid (24.3 mmol) were initially charged. 70 ml of methanol and 80 ml of acetone were added. It was stirred for 3 days at RT. Thereafter, 80 ml of acetone were added and cooled in an ice bath for 2 hours. The precipitate was filtered off, washed with 60 ml of acetone: methylene chloride (1: 1) and dried under high vacuum. Yield: 49.4 g (79.7%); colorless solid
- Citric acid dibenzyl ester (as sodium salt) and b) unsymmetrical
- Citric acid diesters observed. Alcohols used: 2-phenylethanol, allyl alcohol, glycol, butane-1,4-diol, 2-butanol, tert-butanol, glycerol Example 11
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102011054602A DE102011054602A1 (de) | 2011-10-19 | 2011-10-19 | Verfahren zur Synthese von Citronensäureestern |
PCT/EP2012/070501 WO2013057110A1 (de) | 2011-10-19 | 2012-10-16 | Verfahren zur synthese von citronensäureestern |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2768795A1 true EP2768795A1 (de) | 2014-08-27 |
Family
ID=47046600
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP12775233.5A Withdrawn EP2768795A1 (de) | 2011-10-19 | 2012-10-16 | Verfahren zur synthese von citronensäureestern |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2768795A1 (de) |
DE (1) | DE102011054602A1 (de) |
WO (1) | WO2013057110A1 (de) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102016122527A1 (de) | 2016-11-22 | 2018-05-24 | Bergische Universität Wuppertal | Verfahren zur Synthese von Citronenmonosäureestern |
EP3752481A1 (de) | 2018-02-14 | 2020-12-23 | Basf Se | Verfahren zur herstellung grenzflächenaktiver kondensate von citronensäure sowie produkte dieses verfahrens |
EP3752480B1 (de) | 2018-02-14 | 2023-06-21 | Basf Se | Verfahren zur herstellung einer oberfl& xc4;chenaktiven mischung umfassend kondensationsprodukte von & x391;-hydroxycarbons& xc4;uren mit 1,2-alkandiolen |
EP3752126A1 (de) | 2018-02-14 | 2020-12-23 | Basf Se | Verwendung von 1,2-alkandiolen als schaumverbesserer für citronensäureestertenside umfassend ethoxylierte alkohole |
CN111807958A (zh) * | 2020-08-14 | 2020-10-23 | 蔚源生物科技(平顶山)有限公司 | 一种咖啡酸苯乙酯的合成方法 |
CN112574038A (zh) * | 2021-01-07 | 2021-03-30 | 北京微量化学研究所 | 一种柠檬酸单酯的选择性合成方法 |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4271311A (en) * | 1979-07-13 | 1981-06-02 | Standard Oil Company (Indiana) | Esterification of phenol catalyzed with a strong base plus boron |
US4866203A (en) | 1987-03-10 | 1989-09-12 | Lever Brothers Company | Method for synthesizing a salt of a monoester of citric acid |
US5089531A (en) * | 1989-07-07 | 1992-02-18 | Lever Brothers Company, Division Of Conopco, Inc. | Compositions incorporating a salt of monoester of citric acid and a method for synthesizing the monoester |
-
2011
- 2011-10-19 DE DE102011054602A patent/DE102011054602A1/de not_active Withdrawn
-
2012
- 2012-10-16 EP EP12775233.5A patent/EP2768795A1/de not_active Withdrawn
- 2012-10-16 WO PCT/EP2012/070501 patent/WO2013057110A1/de active Application Filing
Non-Patent Citations (2)
Title |
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None * |
See also references of WO2013057110A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE102011054602A1 (de) | 2013-04-25 |
WO2013057110A1 (de) | 2013-04-25 |
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