TWI389882B - An electrochemical process to prepare a halogenated carbonyl group-containing compound - Google Patents

Description

Electrochemical method for preparing halogenated carbonyl-containing compound

This invention relates to a novel electrochemical process for the preparation of halogenated carbonyl containing compounds such as carboxylic acids. In a particular embodiment, it is a method of producing monochloroacetic acid by chlorination of acetic acid.

In the industry, monochloroacetic acid is prepared by reacting acetic acid with chlorine. This process for the preparation of monochloroacetic acid is well known and it is common to react a mixture of liquid acetic acid (HAc) with chlorine in a reactor under anhydrous conditions. There are a number of compounds that can be used to form such anhydrous conditions. If acetic anhydride is used, it can be immediately converted to ethyl chlorochloride with hydrochloric acid, which is the catalyst for this process. The process is usually carried out at a pressure of from 1 to 6 barA and a temperature of from 80 to 180 °C. In the reactor, monochloroacetic acid (MCA) and gaseous HCl and by-products are formed, examples of by-products being dichloroacetic acid (DCA) and trichloroacetic acid (TCA).

After the reaction product mixture containing MCA has passed through the reactor and catalyst recovery zone, DCA is present in significant amounts (typically about 3-10%). The product mixture containing MCA/DCA is then directed to a unit to reduce the amount of DCA in the MCA. This can be done by physical separation (such as melt crystallization) or by chemical conversion (such as reduction of DCA by hydrogen in the presence of a hydrogenation catalyst (eg, a metal-based catalyst). However, this catalyst not only reduces DCA, but also reduces MCA to a certain extent, which is of course undesirable. Furthermore, the reduction unit and its operation are expensive and thus increase the manufacturing cost of the MCA end product.

The low boiling component is then removed from the MCA by conventional vacuum distillation. A method for preparing MCA by electrochemical methods has been disclosed by A. Youtz et al., "Depolarization of the Chlorine Electrode by Organic Compounds" in J. Am . Chem Soc ., 1924, 46, 549. The method encompasses reacting 70% acetic acid in an aqueous solution with hydrochloric acid to produce chloroacetic acid.

The electrochemical process for preparing halogenated carboxylic acids (derivatives) in an aqueous environment has the disadvantage that only a small amount of the (mono)halogenated carboxylic acid is formed. Furthermore, the main product of electrolysis in an aqueous chloride environment is typically chlorine, which is undesirable because it is an additional waste stream and in addition the combination of chlorine and hydrogen may make the reaction off-gas mixture susceptible to explosion.

It is an object of the present invention to provide a process for the preparation of halogenated carbonyl-containing compounds by using inexpensive and commercially available starting materials without the need for post-treatment of the simultaneously produced compounds. Another object of the present invention is to provide a process for producing a monohalogenated carbonyl-containing compound having less dihalogenated, trihalogenated or polyhalogenated by-product content relative to the above-described industrial process. Also, it is an object of the present invention to provide a method that can be easily integrated into existing hardware for use in the above-described industrial methods of the prior art without requiring strict physical conditions. Another object is to provide a process for the production of a carbonyl containing compound which is selectively halogenated at the alpha carbon atom (i.e., the carbon atom adjacent to the carbonyl group). A further object is to provide a process which, for example, provides improved yields when compared to the aqueous electrochemical process of Youtz et al., and provides a by-product of good value.

The present invention now provides a process for the preparation of a halogenated carbonyl-containing compound by reacting the corresponding carbonyl-containing compound with a hydrogen halide H-X, an organic halide R'-X and/or a halogen salt M ⁿ⁺ under substantially anhydrous conditions. -X _n ^- an electrochemical reaction wherein X is a chlorine, bromine or iodine atom, and R' may be a linear or branched alkyl or aryl group, which may optionally contain, for example, oxygen, nitrogen, chlorine, bromine, One or more heteroatoms of fluorine or iodine, wherein the halogen atom X can be electrochemically separated, Mn ⁺ is a quaternary ammonium, alkaline earth metal, alkali metal or metal cation, and n is a valence of the metal cation M ⁿ⁺ An integer from 1 to 5.

Substantially anhydrous conditions are defined as water having less than 1% by weight, preferably less than 0.1% by weight, more preferably about zero, in the reaction mixture; these conditions are preferably completely anhydrous, which may be used in the reaction mixture. When the compound of the water scavenger is reached.

Surprisingly, halogen X can only be selected from the group consisting of chlorine, bromine and iodine because it cannot be fluorinated using the process of the invention. In this technique, see, for example, P. Sartori, N. Ignat'ev, "The Actual state of our knowledge about mechanism of electrochemical fluorination in anhydrous hydrogen fluoride (Simons process)", Journal of Fluorine Chemistry 87 ( 1998 ) ), pp. 157-162 , which discloses a method of fluorinating a number of organic compounds; however, normalization of such reactions produces a polyfluorination reaction and does not produce a specific alpha-carbon fluorination.

Halogen gases (such as chlorine) are not required when using the process of the present invention, but instead of using hydrogen halides, organic halides or halide salts, such materials are generally more widely available and less expensive than the starting materials of current industrial processes. The process of the present invention produces a halogenated carbonyl containing compound and hydrogen as a reaction product. Any unreacted halide source can be readily recovered and the unreacted carbonyl containing compound is also the case. The by-product hydrogen formed can be readily separated and can be used as an energy source or a starting compound for, for example, other chemical processes, and thus exhibits commercial value.

Surprisingly, it has been found that only very small amounts of dihalogenated and/or more halogenated carbonyl containing compounds are formed; typically in the case of halogenated carboxylic acids, the amount of dihalogenated carboxylic acid is less than 0.3% by weight and is trihalogenated. The amount of the higher halogenated carboxylic acid, even when formed, is below the detectable limit (i.e., less than 50 ppm). Since the by-product of the reaction is hydrogen (i.e., gas bubbles), it is also beneficial that the reaction mixture remains well mixed without agitation.

In the process of the present invention, a current yield of 80% of the monohalogenated carboxylic acid (derivative) has been achieved. Higher current production is expected to be achieved. In contrast, electrochemical chlorination of acetic acid in an aqueous environment produces low current yields typically below 1%.

Current production (also referred to as current efficiency) is described in Bard-Stratman, Encyclopedia of Electrochemistry, Organic Electrochem. , Vol. 8, Chapter 2.3.1, page 31. In short, current efficiency or current production means the fraction of the battery current used to form the product or the fraction of the transferred charge (integrated over time).

Surprisingly, it has been found that in the process of the invention it is also possible to efficiently convert a dihalogenated and/or higher halogenated carbonyl containing compound to a monohalogenated carbonyl containing compound. Thus, in one embodiment, the starting material may be a mixture of a carbonyl-containing compound (R'-X) containing at least a dihalogenated and/or higher halogenated compound and a non-halogenated carbonyl-containing compound, wherein the dihalogenation and/or The amount of the carbonyl-containing compound which is more or more halogenated is preferably at most the amount of the carbonyl-containing compound which is not halogenated. It has been found that the use of this starting mixture can still produce a reaction product comprising a predominantly monohalogenated carbonyl containing compound or, in other words, a very low amount of dihalogenated and/or higher halogenated carbonyl containing compound. This is due to the fact that the dihalogenated and/or higher halogenated carbonyl containing compound electrochemically reacts at the cathode under electrochemical conditions to form hydrogen halide in situ.

In two documents, namely, "Effect of small amounts of tetramethyl-and tetraethylammonium ions on electroreduction kinetics of certain organic compounds in solutions of tetrabutylammonium salts" by LNNekrasov et al., Elektrokhimiya, Vol. 24, No. 4, No. 560 -563, 1988 and A. Inesi, L. Rampazzo "Electrochemical reduction of halogen containing compounds at a mercury cathode: chloroacetic, dichloroacetic acids and corresponding ethylesters in dimethylformamide", Electroanalytical Chemistry and Interfacial Elelctrochemistry , 44 (1973), On pages 25-35, it is disclosed that the reduction of trichloroacetic acid to dichloroacetic acid can be achieved by electrochemical methods, but it has not been disclosed or suggested that the compound can be used as a halogen source for halogenation of a carbonyl-containing compound (i.e., as a The compound R'-X) is defined to produce a monohalogenated carbonyl-containing compound.

Accordingly, in one embodiment of the invention there is provided a process wherein the organic halide R'-X is a dihalogenated and/or more halogenated carbonyl containing compound. Or in other words, there is provided a process for the preparation of a halogenated carbonyl-containing compound by subjecting the corresponding carbonyl-containing compound to a dihalogenated and/or more halogenated carbonyl-containing compound under substantially anhydrous conditions (as appropriate) The hydrogen halide H-X, another organic halide R'-X and/or the halogen salt M ⁿ⁺ -X _n ^- ) is electrochemically reacted, wherein X is a chlorine, bromine or iodine atom, and R' is a linear chain. Or a branched alkyl or aryl group, which may optionally contain one or more heteroatoms such as oxygen, nitrogen, chlorine, bromine, fluorine or iodine, wherein the halogen atom X can be electrochemically separated, Mn ⁺ is four a grade of ammonium, alkaline earth metal, alkali metal or metal cation, and n is an integer from 1 to 5 depending on the valence of the metal cation M ⁿ⁺ .

The process of the present invention can also be used as the second step in the conventional process for preparing a monohalogenated carbonyl-containing compound by chemical reaction of a carbonyl containing compound with a halogen source. Likewise, the process of the invention can be used to treat, for example, a reaction mixture of a monohalogenated carboxylic acid (derivative) with a carboxylic acid (derivative) comprising monohalogenated and dihalogenated and/or higher halogenated. The mother liquor produced upon separation, which mother liquor then comprises a mixture of the remaining monohalogenated carboxylic acid (derivative) with a relatively large amount of dihalogenated and/or higher halogenated carboxylic acid (or derivative thereof).

Separation methods include conventional separation methods available to those skilled in the art, such as distillation, extraction, and crystallization, with crystallization being optimal.

This aspect of the invention provides a process for the preparation of a halogenated carbonyl-containing compound by first chemically reacting a carbonyl-containing compound with a chlorine, bromine or iodine molecule and subsequently electrochemically treating it according to the electrochemical methods disclosed above. The reaction mixture is achieved, and the present invention provides a process wherein the starting mixture is a carbonyl containing compound which is monohalogenated with a carbonyl containing compound which is monohalogenated and/or more halogenated. The mother liquor obtained when the reaction mixture is separated.

In the process of reacting a carbonyl-containing compound with a corresponding dihalogenated and/or more halogenated carbonyl-containing compound, the net reaction is a dihalogenated and/or higher halogenated carbonyl containing compound and a corresponding carbonyl containing compound. The reaction is carried out to produce a monohalogenated carbonyl containing compound.

Incorporating conventional methods, followed by embodiments of the electrochemical method according to the present invention have important advantages, namely, products of conventional methods (i.e., hydrogen halides and carbonyl containing compounds, monohalogenated carbonyl containing compounds, and dihalogenated and / or a mixture of higher halogenated carbonyl containing compounds) is the starting material for the electrochemical step. There is therefore no need to process the product stream of the conventional process; alternatively, the product stream of the conventional process can be used directly as the starting material stream in the electrochemical step.

Suitably, higher halogenation means up to 10, and preferably 3 to 6 chlorine, bromine and/or iodine groups are present in the carbonyl containing compound.

The invention further provides an apparatus for carrying out the above method. In this aspect, there is provided a device comprising a chemical reactor (A) connected to an electrochemical reactor (B) via an outlet (5) and optionally outlets (2), (3) and (4), Wherein reactor (B) is connected to physical separation unit (C) via outlet (9). This device is illustrated in Figure 1.

The chemical reactor (A) can be a reaction vessel (eg, heated and/or cooled and/or isolated) of a suitable material (eg, glass lined steel). The chemical reactor preferably contains internal components such as mechanical agitators, heat exchanger tubes, inlet tubes (eg, for feedstock and recycle streams), and/or sensors (such as temperature sensors, pressure sensors) , liquid level sensor). The chemical reactor (A) may optionally have a UV illuminating member, such as a UV lamp, for converting a halogen gas into a halogen atom.

Referring in more detail to Figure 1, a halide, a carbonyl containing compound, optionally a catalyst, and optionally an electrolyte, are supplied to the chemical reactor (A) via inlets (1), (2), (3), and (4), respectively. Two or more of these inlets may be combined into one inlet to react to the intermediate product, which is supplied to the electrochemical reactor (B) via the outlet (5). The gas component formed in the chemical reactor (A) and separated from the chemical reactor (A) may also be partially or completely introduced into the electrochemical reactor (B) via the outlet (6), in which case Next, the outlet (6) can be combined with the outlet (5) to form an outlet. More or even all of the carbonyl-containing compound, catalyst and electrolyte may be fed into the electrochemical reactor (B) via inlets (2), (3) and (4), respectively, or two or more of these inlets Can be combined into one entrance. In an embodiment, the electrochemical reactor (B) may be provided with an additional inlet stream (7) containing a halide (gas or liquid).

The electrochemical reactor (B) is a device comprising at least one anode and at least one cathode of any suitable material as described above and preferably placed therein in a suitable geometry (such as a parallel plate or concentric cylinder, packed bed) Or a container for the anode and cathode of a fluidized bed battery. In a more preferred embodiment, the electrochemical reactor contains one or more battery separators (such as a diaphragm or membrane). In another preferred embodiment, the electrochemical reactor (B) is a reactor containing parallel electrodes in a vessel with or without internal or external fluid recirculation. The anode and cathode are connected to a direct current source that supplies current to the electrodes. The electrodes can be connected to a power supply in a unipolar configuration or in a bipolar configuration. In a preferred embodiment, the electrochemical reactor (B) simultaneously produces a monohalogenated compound by halogenating the starting material at the anode and dehalogenating the dihalogenated and more halogenated compound at the cathode. In some embodiments, hydrogen is separated from the reactor via an outlet (8) at the cathode in an electrochemical reactor.

The substantially reduced dihalogenated and/or higher halogenated product is supplied from the electrochemical reactor (B) to the physical separation unit (C) via the outlet (9). The hydrogen halide and other components formed in the chemical reactor (A) and/or the electrochemical reactor (B) are separated from the product via the outlet (11) and optionally returned to the chemical reactor via the outlet (10). (A) and / or electrochemical reactor (B). In addition, the electrolyte can be fed into the chemical reactor (A) and/or the electrochemical reactor (B) via the inlet (4), and the electrolyte can be separated from the reaction product and the reactant in the physical separation unit (C) and can be visualized. The situation is returned to reactors A and B via outlet (10).

The physical separation unit (C) is a device which may comprise one or more distillation columns, an extraction column, an absorption column or a combination thereof, the device being adapted to separate the electrochemical reactor product entering the unit C via the outlet (9) into a halogenated product. The product stream, which contains the predominantly monohalogenated and dihalogenated carbonyl derivative exiting the apparatus of the present invention via outlet (11).

In another embodiment, the apparatus comprises an additional separation unit (D) for separating the monohalogenated compound from the corresponding dihalogenated and higher halogenated compound. This device is illustrated in Figure 2.

Referring in more detail to Figure 2, in the apparatus of this embodiment, the product from the chemical reactor (A) is introduced via an outlet (5) to the physical separation unit (C) as described above to form a chemical reactor The electrolyte and other components or products in A are separated from the monohalogenated, dihalogenated and/or more halogenated carbonyl product delivered to separation unit D via outlet (12).

Separation unit D comprises a separation member capable of separating the monohalogenated compound from the corresponding dihalogenated and higher halogenated compound. These separate components can be distillation columns, crystallization units, extraction units, or any combination of such components to provide the desired separation. Unit D produces a purified monohalogenated product separated via an outlet (14) and a substantially enriched dihalogenated and/or higher halogenated product stream, which is introduced via outlet (13) as described above In the electrochemical reactor (B).

In the apparatus of the embodiment shown in Figure 2, the substantially enriched monohalogenated product from electrochemical reactor (B) can be introduced into chemical reactor (A) via outlet (15). The stream containing the electrolyte and other components may be introduced into the electrochemical reactor (B) and/or the chemical reactor (A) from the physical separation unit (C) via the outlet (10) as appropriate. Optionally, a stream containing a halide (gas or liquid) and a stream containing a carbonyl-containing compound may be introduced into the electrochemical unit (B) via inlet (7) and inlet (2), inlet (7) and inlet (2). ) can be combined into one entrance. In the electrochemical reactor (B), hydrogen can be produced at the cathode and separated from the reactor via an outlet (8).

In a preferred embodiment, the process of the invention is carried out in the substantial absence of solvent. "Substantially solvent free" means that up to 5% of the solvent is present in the reaction mixture. The term solvent is intended to encompass any of the materials in which at least the starting material of the reaction is soluble but does not include one of the reactants/products. In the process of the invention, the reaction mixture preferably contains less than 2% solvent. Preferably, about 0% of the solvent is present.

The purifying reaction occurring in the method of the present invention can be understood as: H-X+R-COY → X-R-COY+H ₂ R'-X+R-COY--->X-R-COY+R'-H or MX _n +n R -COOH → (X-R-COO) _n M+nH ₂

The carbonyl-containing compound R-COY or R-COOH to be halogenated may be any compound containing an α-carbon hydrogen atom, preferably a liquid at the reaction temperature. The carbonyl-containing compound R-COY may be an aldehyde, a ketone, a carboxylic acid, a carboxylic anhydride or a fluorenyl halide. R-COY and R-COOH are preferably a carbonyl-containing compound, wherein R is an alkyl group having an α-hydrogen group, an alkylene group or an aryl group, and may be linear, cyclic or branched, and may optionally contain one Or a plurality of heteroatoms such as oxygen, nitrogen, chlorine, bromine or iodine, and Y is hydrogen, a hydroxyl group, a halogen atom or a group R" or OCOR", wherein each R" is independently a hydrogen atom or an alkyl group, an alkyl group Or aryl. Y is more preferably a hydroxyl group, a halogen atom, a group R" or OCOR", wherein R" is a C ₁ -C ₁₀ alkyl group or a C ₁ -C ₁₀ alkylene group, and R is a C ₁ -C ₂₆ Alkyl or C ₁ -C ₂₆ alkylene. The carbonyl-containing compound is more preferably an unsubstituted C ₂ -C ₂₆ carboxylic acid, more preferably acetic acid, propionic acid or a fatty acid, most preferably acetic acid. A fatty acid is defined as a carboxylic acid having a hydrocarbyl group containing from 1 to 22 carbon atoms, preferably from 8 to 22 carbon atoms, which may be saturated or unsaturated, linear or branched. It is assumed that fatty acids derived from natural fats and oils have at least 8 carbon atoms. Preferred fatty acids in the present invention are unbranched C ₈ -C ₂₆ carboxylic acids and are more preferably, for example, a group of natural fatty acids as described in CRC Handbook of Chemistry and Physics , 1989, D-220.

The halide is a chloride, bromide or iodide, more preferably a chloride or bromide, most preferably a chloride.

The organic halide R'-X can be any compound which can be dehalogenated by an electrochemical step, for example in Lund, Hammerich, Organic Electrochemistry , 4th edition, Chapter 8, "Halogenated organic compounds" (Marcel Dekker, 2001). Compounds disclosed in the above. R'-X is preferably a halogenated hydrocarbon compound which may contain other substituents (e.g., nitrogen or oxygen). R'-X is preferably a carbonyl-containing compound which is dihalogenated and/or which is more halogenated.

The halogen salt M ⁿ⁺ -X _{n is} preferably wherein M is an alkaline earth metal, an alkali metal or a metal cation, and M is more preferably a Na, K, Li, Mg, Ca or Ba cation, and more preferably an alkali metal cation, most preferably a halide salt of a lithium, sodium or potassium cation.

In a more preferred embodiment, the reaction mixture comprises essentially only the reactants, products and auxiliaries, ie more than 95% by weight of the reaction mixture is the starting materials, products and auxiliaries, and optimally it comprises more than 99% by weight. Reaction mixture. Auxiliaries can be defined as agents that can be present in the process of the invention due to functionality, such as catalysts and supporting electrolytes.

In principle, no electrolyte is required in the process as long as sufficient current can pass through the fluid under the processing conditions. In a preferred embodiment, a supporting electrolyte is present in the reaction mixture. The electrolyte is a mixture of non-aqueous compounds which are sufficiently soluble and provide sufficient electrical conductivity in the applied reaction mixture, can be easily separated and recovered, and can sufficiently stably resist oxidation and reduction. Examples of such supporting electrolytes can be, for example, F. Beck, Elektroorganische Chemie , Verlag Chemie GmbH, Weinheim, 1974, Chapter 3.3, pages 104-110 or D. Pletcher, A First Course in Electrode Processes, The Electrochemical Consultancy , Alresford Press Ltd., 1991, Chapter 2.3, any combination of ions given on pages 57-72, and may include ions such as OH ^- , I ^- , Br ^- , Cl ^- , F ^- , NO ₃ ^- , SO ₄ ^2- , HCO ^3- , Fe(CN) ₆ ^3- , ClO ₄ ^- , BF ₄ ^- , PF ₆ ^- , H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Ca ²⁺ , Mg ²⁺ , Al ³⁺ , La ³⁺ , Ag ⁺ , NH ₄ ⁺ , [N(CH ₃ ) ₄ ] ⁺ , [N(C ₂ H ₅ ) ₄ ] ⁺ , [N(C ₄ H ₉ ) ₄ ] ⁺ , [N(C ₂ H ₅ )H] ⁺ . The electrolyte is more preferably a salt which is soluble in the carboxylic acid to be halogenated, and the salt does not participate in the halogenation reaction or participates in the halogenation reaction and then contains the same halogen anion as the halogen source of the reaction to prevent formation of a different halogenated carbonyl-containing compound. In a more preferred embodiment, the electrolyte is a halide salt such as NaCl, NaBr, NaI, KCl, KBr, KI, LiCl, LiBr, LiI, MgCl ₂ , MgBr ₂ , MgI ₂ , CaCl ₂ , CaBr ₂ , CaI ₂ , BaCl ₂ , BaBr ₂ , BaI ₂ . In a preferred embodiment, the metal salt MX _{n is} used as a supporting electrolyte.

In another preferred embodiment, a reaction accelerating compound (also referred to herein as a "catalyst") is present in the reaction mixture. In a more preferred embodiment, the compound is a carboxylic acid anhydride (derivative) to be halogenated or an acid halide thereof. In embodiments comprising a two-step process (i.e., a chemical halogenation step followed by an electrochemical step), the acid halide catalyst described above can be formed in the reaction mixture, and thus it is not necessary to use a product in the chemical step, such as PCl ₃ Or SOCl ₂ or SO ₂ Cl ₂ , COCl ₂ , anhydride or sulfur (used as a catalyst) can be added. As indicated above briefly, these anhydride and acid halide type compounds have the additional advantage that they scavenge water to produce a carboxylic acid and thus enable the reaction conditions to be completely anhydrous. The catalyst is used in a typical amount between 2 and 30% by weight of the total reaction mixture.

An additional advantage of the process of the invention is that the catalyst compound is not degraded by the water present in the reaction mixture because the electrochemical reaction is carried out in a non-aqueous environment.

The electrode used may be selected from any material that does not degrade in the reaction mixture under reaction conditions to produce improper by-products. In this aspect, the choice of anode material is particularly important because the anode is most susceptible to degradation during processing conditions. In a preferred embodiment, the anode is carbon (such as boron doped diamond, graphite, vitreous carbon), ceramic (such as magnetite, ie, Fe ₃ O ₄ or Ebonex , that is, mixed titanium oxide), a metal alloy (such as platinum/ruthenium) or a noble metal (such as Au, Ag, Pd, Pt, Ti), which may optionally contain a mixed metal oxide such as IrO ₂ /RuO ₂ (for example, IrO ₂ /RuO ₂ on Titanium, Shape Stabilized Anode: DSA Electrode), and the cathode is carbon (such as boron-doped diamond, graphite, glassy carbon), metal (such as nickel, lead, mercury, titanium, iron, chromium), metal alloy (such as stainless steel (Cr-Ni-Fe), Monel (Cu-Ni), brass (Cu-Zn) or metal oxide (such as Pb/PbO ₂ )) or any other electrode that is stable in the system and does not produce significant amounts of improper by-products. Examples of electrode materials are mentioned in the reference to AJ Bard and M. Stratmann, Encyclopedia of Electrochemistry, Organic Electrochem. , Vol. 8, Chapter 2.4.1, page 39.

Additionally, in the method of the present invention, the electrodes are preferably selected such that their specific surface area is as high as possible and the distance between the cathode and the anode is as small as possible. Those skilled in the art will not have the problem of selecting an electrode suitable for this purpose. Concentric electrodes, porous electrodes, parallel plate electrodes, packed bed electrodes, fluidized bed electrodes can be described as non-limiting examples of electrodes that meet one or more of the above criteria. The electrode configuration can be monopolar or bipolar.

The current density during the process of the invention is generally between 0.1 and 7 kA/m ² , preferably between 0.5 and 4 kA/m ² , and most preferably between 1 and 2 kA/m ² . The battery voltage (primarily but not exclusively) is typically between 1 and 10 volts depending on the current density applied, the conductivity of the reactive fluid, and the distance between the electrodes.

The process of the present invention can be combined with a UV treatment step whereby a halogen gas is added to the reaction system, converted to a halogen atom by UV irradiation, and also allowed to react with a carbonyl-containing compound to produce a carbonyl-containing compound to be halogenated.

The process of the invention may be a batch, semi-batch or continuous process; it is preferably a continuous process.

The process can be carried out at a pressure generally in the range of from 1 to 10 barA; the pressure is preferably between 0.9 and 5 barA, most preferably about 1 to 2 barA. BarA means absolute bar.

The process is usually carried out at a temperature between 11 and 200 ° C, preferably between 20 and 150 ° C, more preferably between 75 and 140 ° C, optimally between 80 and 120 ° C.

The invention is further illustrated by the following examples and comparative examples.

Instance Example 1 uses HCl to chlorinate acetic acid

In a reaction vessel containing a graphite anode and a cathode (Material Type 6503, Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 7% by weight of anhydrous chlorination. Calcium (JT Baker, No. 0070, 95% by weight minimum), 69% acetic acid (Fluka, 45731, >99.8% by weight) and 24% by weight of acetamidine (Fluka, 00990, >99%) in an amount of 800 grams The mixture was preheated to 70 ° C and electrolyzed at an average current of 20 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC).

Table 1 shows the measurement of one chloroacetic acid (MCA) concentration and dichloroacetic acid (DCA) concentration (by weight % relative to the sum of acetic acid (HAc), MCA and DCA amounts) by HPLC and transfer in the process Comparison of the amount of charge.

Example 2 uses CaCl ₂ (in the absence of HCl) to chlorinated acetic acid

In the reactor as referred to in Example 1, 72% by weight of acetic acid (Fluka, 45,731, >99.8% by weight), 21% by weight of acetonitrile (Fluka, 00990, >99%) and 7 weights A 650 gram mixture of % anhydrous calcium chloride (JT Baker, No. 0070, minimum 95% by weight) was preheated to 70 ° C and electrolyzed at a current between 5 and 20 amps. In contrast to Example 1, no hydrogen chloride gas was added to the reaction mixture in this example.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC).

The results of the analysis also show that MCA can also be produced from the mixture in the absence of hydrogen chloride.

Table 2 shows the concentration of one of chloroacetic acid (MCA) and dichloroacetic acid (DCA) by HPLC (in % by weight relative to the sum of the amounts of acetic acid (HAc), MCA and DCA) and transferred during the process A comparison of the amount of charge.

Example 3 uses dichloroacetic acid to chlorinate acetic acid

In the reactor as mentioned in Example 1, 60% by weight of acetic acid (Fluka, 45731, >99.8% by weight), 19% by weight of ethyl chloroform (Fluka, 00990, >99%), 5 weight 100 parts of anhydrous calcium chloride (JT Baker, 0070, 95% by weight minimum) and 16% by weight of dichloroacetic acid (Acros Chemicals, Lot A0220473, 99+%) were preheated to 70 ° C and at 20 amps Electrolysis at the current. Hydrogen chloride is added to the reaction mixture.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC).

The analysis results show that the yield of MCA is almost twice as high as in the example 2 compared to Example 2. The acetic acid is chlorinated and the DCA is hydrogenated to MCA.

Table 3 shows the concentration of one of chloroacetic acid (MCA) and dichloroacetic acid (DCA) by HPLC (in % by weight relative to the sum of the amounts of acetic acid (HAc), MCA and DCA) and transferred during the process A comparison of the amount of charge.

Example 4 uses HCl chloride propionic acid

In the reactor as mentioned in Example 1, 65 wt% propionic acid (Fluka, lot number 1241470, >99 wt%), 30 wt% propionic anhydride (Aldrich, batch 05003 HC-026, 97%) and A 840 g mixture of 5% by weight of anhydrous calcium chloride (JT Baker, No. 0070, a minimum of 95% by weight) was preheated to 70 ° C and electrolyzed at a current between 1 and 9 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC).

The results of the analysis show that 1-chloropropionic acid can be produced from the mixture.

Table 4 shows the propionic acid concentration and 1-chloro-propionic acid concentration (% by weight relative to the sum of propionic acid and 1-chloropropionic acid) as measured by HPLC and the amount of charge transferred during the process. Comparison.

Comparative Example 5 chlorinated acetic acid in an aqueous environment

A mixture containing 500 ml of hydrochloric acid (10% by weight HCl in water) was charged into a 1 liter beaker and electrolyzed at a current of 2 amps at room temperature to produce chlorine gas. After two hours of electrolysis, 150 ml of acetic acid (70% by weight) was added to the reaction mixture, which was re-electrolyzed at 2 amps for 1.5 hours at room temperature.

The samples obtained during this process were measured by ¹ H-NMR. Only a trace amount of MCA was detected by NMR, and the amount of DCA was below the detection limit (the detection limit of MCA and DCA of the NMR instrument was about 50 ppm).

Example 6: Preparation of bromoacetic acid using LiBr

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 11% anhydrous lithium bromide, 33% A mixture of barium bromide and 56% acetic acid (Fluka 00990, >99%) in an amount of 900 grams was preheated to 70 ° C and electrolyzed at an average current of 20 amps. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 83 A-h passed through the electrode, 12.97% bromoacetic acid and 0.017% dibromoacetic acid were formed.

Example 7: Using Sodium Chloride as an Electrolyte Chlorination of Acetic Acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 11% anhydrous sodium chloride, A mixture of 33% acetic anhydride and 56% acetic acid (Fluka 00990, >99%) in an amount of 808 grams was preheated to 70 ° C and electrolyzed at an average current of 3.8 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 15.9 A-h passed through the electrode, 3.66% MCA and 0.043% DCA were formed.

Example 8: Using lithium chloride as an electrolyte to chlorinate acetic acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 1.3% anhydrous lithium chloride, A mixture of 6.6% acetamidine chloride and 92.1% acetic acid (Fluka 00990, >99%) in an amount of 808 grams was preheated to 70 ° C and electrolyzed at an average current of 20 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 112 A-h passed through the electrode, 22.76% MCA and 0.108% DCA were formed.

Example 9: Using potassium chloride as an electrolyte chlorinating acetic acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 10% anhydrous potassium chloride, A mixture of 24% acetamidine chloride and 66% acetic acid (Fluka 00990, >99%) in an amount of 808 grams was preheated to 70 ° C and electrolyzed at an average current of 10 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 57.7 A-h passed through the electrode, 13.39% MCA and 0.57% DCA were formed.

Example 10: Chlorination of acetic acid using trichloroacetic acid and HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 11.9% trichloroacetic acid (TCA). The mixture of 4.8 grams of 4.8% anhydrous lithium chloride, 11.9% acetamidine chloride and 71.4% acetic acid (Fluka 00990, >99%) was preheated to 70 ° C and electrolyzed at an average current of 30 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC).

The results in Table 5 indicate that both DCA and TCA levels have decreased and MCA levels have increased at the end of the process.

Example 11: Using lithium chloride as an electrolyte to reduce the mother liquor (using dichloroacetic acid and HCl to chlorinate acetic acid)

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 30% dichloroacetic acid (DCA). a mixture of 5% anhydrous lithium chloride, 15% ethyl chloroform, 30% monochloroacetic acid (MCA) and 20% acetic acid (Fluka 00990, >99%) in an amount of 1,007 grams preheated to 70 ° C and Electrolysis at an average current of 30 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). The results in Table 6 show that both HAc and DCA levels are reduced and MCA levels are increased at the end of the process.

Example 12: Calcium chloride was used as an electrolyte to reduce the mother liquor (using dichloroacetic acid and HCl to chlorinate acetic acid)

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 30% dichloroacetic acid (DCA). ), a mixture of 5% anhydrous calcium chloride, 15% ethyl hydrazine chloride, 30% monochloroacetic acid (MCA) and 20% acetic acid (Fluka 00990, >99%) in an amount of 1,007 grams is preheated to 70 ° C and Electrolysis at an average current of 30 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process.

Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). The results in Table 7 indicate that at the end of the process, both HAc and DCA levels decreased while MCA levels increased.

Table 7: Monochloroacetic acid (MCA), dichloroacetic acid (DCA), and acetic acid (HAc) concentrations of Example 12 as measured by HPLC (in weight % relative to the sum of the amounts of HAc, MCA, and DCA) and Comparison of the amount of charge transferred during this process

Example 13: Magnesium chloride was used as an electrolyte to reduce the mother liquor (using dichloroacetic acid and HCl to chlorinate acetic acid)

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 30% dichloroacetic acid (DCA). a mixture of 5.2% anhydrous magnesium chloride, 15% ethyl hydrazine chloride, 30% monochloroacetic acid (MCA) and 20% acetic acid (Fluka 00990, >99%) in an amount of 1,007 grams preheated to 70 ° C and at 30 amps Electrolysis at the average current. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). The results in Table 8 indicate that at the end of the process, the HAc content and DCA content decreased while the MCA content increased.

Example 14: Using zinc chloride as an electrolyte to chlorinate acetic acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 5% anhydrous zinc chloride, A mixture of 13% acetamidine chloride and 82% acetic acid (Fluka 00990, >99%) in an amount of 1,607 grams was preheated to 70 ° C and electrolyzed at an average current of 25 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 162 A-h passed through the electrode, 15.67% MCA and 0.10% DCA were formed.

Example 15: Using iron (III) chloride as an electrolyte to chlorinate acetic acid

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , it will contain 5% anhydrous ferric chloride ( III) A mixture of 13% acetamidine chloride and 82% acetic acid (Fluka 00990, >99%) in an amount of 1,607 grams was preheated to 70 ° C and electrolyzed at an average current of 30 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 192 A-h passed through the electrode, 4.73% MCA and 0.10% DCA were formed.

Example 16: Use of Aluminum Chloride as Electrolyte to Chloride Acetic Acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 580 cm ² and an effective cathode area of 530 cm ² , will contain 5% anhydrous aluminum chloride, A mixture of 13% acetamidine chloride and 82% acetic acid (Fluka 00990, >99%) in an amount of 1,607 grams was preheated to 70 ° C and electrolyzed at an average current of 30 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by high performance liquid chromatography (HPLC). After the charge of 119 A-h passed through the electrode, 12.29% MCA and 0.02% DCA were formed.

Example 17: Chlorination of dimethyl pentanone using HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 47 cm ² and an effective cathode area of 16 cm ² , will contain 6% anhydrous lithium chloride, A mixture of 94% 2,4-dimethylpentanone in 61 grams was preheated to 70 ° C and electrolyzed at an average current of 0.3 amps. Hydrogen chloride gas is added to the reaction mixture during the electrolysis process. Samples obtained from the electrolyte during the electrolysis process were analyzed by NMR.

The results in Table 10 indicate that at the end of the process, 2-chloro-2,4-dimethylpentanone was formed.

Comparative Example 18: Fluorine Acetic Acid Using Trifluoroacetic Acid (TFA)

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands), which has an effective anode area of 47 cm ² and an effective cathode area of 16 cm ² , will contain 4% anhydrous lithium chloride, A mixture of 35.4% TFA, 35.4% acetic acid and 25.2% acetamidine in an amount of 99 grams was preheated to 70 ° C and electrolyzed at an average current of 2 amps. Samples obtained from the electrolyte during the electrolysis process were analyzed by NMR. No evidence of formation of monofluoroacetic acid or difluoroacetic acid was found in the sample. Only MCA and a small amount of DCA were found.

Comparative Example 19: Fluorine Acetate Using KF

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 47 cm ² and an effective cathode area of 16 cm ² , it will contain 4.3% anhydrous potassium fluoride, A mixture of 68.5% acetic acid and 29.2% acetamidine in an amount of 99 grams was preheated to 70 ° C and electrolyzed at an average current of 0.4 amps. Samples obtained from the electrolyte during the electrolysis process were analyzed by NMR. No evidence of formation of monofluoroacetic acid or difluoroacetic acid was found in the sample. Only MCA and a small amount of DCA were found.

Example 20: Using LiCl as an electrolyte to chlorinate dodecanoic acid with HCl

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 47 cm ² and an effective cathode area of 16 cm ² , it will contain 4.9% anhydrous lithium chloride, A mixture of 35.3% acetic acid, 35.3% dodecanoic acid and 24.5% ethyl hydrazine chloride in an amount of 92 grams was preheated to 70 ° C and electrolyzed at an average current of 1 ampere. Samples obtained from the electrolyte during the electrolysis process were analyzed by NMR. After the charge of 3.4 A-h passed through the electrode, 1.3 mol% of 2-chloro-dodecanoic acid was formed.

Example 21: Using HCl to octadecanoic acid

In a reaction vessel containing a graphite anode and a cathode (material type 6503 Le Carbonne Lorraine, Rotterdam, The Netherlands) with an effective anode area of 47 cm ² and an effective cathode area of 16 cm ² , it will contain 4.7% anhydrous lithium chloride, A mixture of 38.3% acetic acid, 33.6% octadecanoic acid and 23.4% ethyl hydrazine chloride in an amount of 92 grams was preheated to 70 ° C and electrolyzed at an average current of 1 ampere. Samples obtained from the electrolyte during the electrolysis process were analyzed by NMR. After the charge of 3.2 A-h passed through the electrode, 1.3 mol% of 2-chloro-octadecanoic acid was formed.

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A. . . Chemical reactor

B. . . Electrochemical reactor

C. . . Physical separation unit

D. . . Separation unit

1 shows an apparatus for preparing a halogenated carbonyl derivative according to the present invention using a chemical reactor (A), an electrochemical reactor (B), and a physical separation unit (C).

2 shows an apparatus for preparing a halogenated carbonyl derivative according to the present invention, which uses a chemical reactor (A), an electrochemical reactor (B), a physical separation unit (C), and a corresponding monohalogenated compound and corresponding Separation unit (D) which is dihalogenated and separated by a more halogenated compound.

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A. . . Chemical reactor

B. . . Electrochemical reactor

C. . . Physical separation unit

Claims (20)

A process for the preparation of a halogenated carbonyl-containing compound, which comprises: reacting a corresponding carbonyl-containing compound having an alpha-carbon hydrogen atom with a dihalogenated and/or higher halogenated carbonyl-containing compound under substantially anhydrous conditions And, as the case may be, an electrochemical reaction with hydrogen halide HX, an organic halide R'-X and/or a halogen salt M ⁿ⁺ -X _n ^- wherein X is a chlorine, bromine or iodine atom, and the R' system may be a straight chain or a branch An alkyl or aryl group of the chain, which may optionally contain one or more heteroatoms wherein the halogen atom X may be electrochemically separated, and Mn ⁺ is a quaternary ammonium, alkaline earth metal, alkali metal or metal cation, and An integer of 1 to 5 is considered depending on the valence of the metal cation M ⁿ⁺ . The method of claim 1, wherein the halogenated carbonyl-containing compound prepared is a monohalogenated compound. The method of claim 2, wherein the halogenated carbonyl-containing compound prepared is halogenated at the α-carbon atom. The method of claim 2, wherein a support electrolyte is additionally present in the electrochemical reaction. The method of claim 4, wherein the supporting electrolyte is a chloride salt. The method of claim 2, wherein a catalyst selected from the group consisting of a mercapto halide and a carboxylic anhydride is additionally added to the electrochemical reaction. The method of claim 1, wherein the halogenated carbonyl-containing compound prepared is halogenated at the α-carbon atom. The method of claim 1, the method further comprising chemically reacting the corresponding carbonyl-containing compound with chlorine, bromine or iodine molecules prior to the electrochemical reaction step. The method of claim 8, wherein the halogenated carbonyl-containing compound prepared is a monohalogenated compound. The method of claim 8, wherein X is a chlorine atom. The method of claim 8, wherein the corresponding carbonyl-containing compound is acetic acid or propionic acid or a fatty acid. The method of claim 8, wherein the method is substantially free of any solvent. The method of claim 1, wherein X is a chlorine atom. The method of claim 1, wherein the corresponding carbonyl-containing compound is acetic acid or propionic acid or a fatty acid. The method of claim 1, wherein a support electrolyte is additionally present in the electrochemical reaction. The method of claim 15, wherein the supporting electrolyte is a chloride salt. The method of claim 1, wherein a catalyst selected from the group consisting of a mercapto halide and a carboxylic anhydride is additionally added to the electrochemical reaction. The method of claim 1, wherein the method is substantially free of any solvent. A process for the preparation of a halogenated carbonyl-containing compound, which comprises: subjecting a monohalogenated carbonyl-containing compound from a carbonyl-containing compound containing a monohalogenation to a carbonyl-containing compound which is dihalogenated and/or more halogenated The reaction mixture is separated to form a mother liquor, and in the mother liquor, the corresponding carbonyl-containing compound having an α-carbon hydrogen atom and the dihalogenated and/or higher halogenated carbonyl-containing compound are treated under substantially anhydrous conditions. The reaction is electrochemically reacted with hydrogen halide HX, organic halide R'-X and/or halogen salt M ⁿ⁺ -X _n ^- wherein X is a chlorine, bromine or iodine atom and R' can be linear or branched. An alkyl or aryl group optionally containing one or more heteroatoms wherein the halogen atom X can be electrochemically separated, Mn ⁺ is a quaternary ammonium, alkaline earth metal, alkali metal or metal cation, and n is a visual The valence of the metal cation M ⁿ⁺ is an integer of 1 to 5. The method of claim 19, wherein the carbonyl-containing compound is additionally added.