Process for decarboxylation of C2-C8 carboxylic acids, derivatives or mixtures thereof

Abstract

The invention relates to a method for producing ketones by a decarboxylated ketonation process of a C2-C8 carboxylic acid, a C2-C8 carboxylic acid derivative or a mixture thereof in the liquid phase. The invention further relates to ketones readily produced by the process of the invention.

Description

Field of the Invention

[0001] The present invention relates to a process for producing ketones by a decarboxylation ketonization process of C2-C8 carboxylic acids, C2-C8 carboxylic acid derivatives or mixtures thereof in liquid phase. The present invention further relates to ketones which are easily produced by the process of the present invention. Background Art

[0002] Volatile ketones are versatile compounds that can be used in a variety of applications. Acetone (CH3-CO-CH3) is used, for example, directly as a solvent or as a raw material for the manufacture of some green, non-VOC solvents like methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), hexanediol (HGL) or glycerol ketal, in particular 2,2-dimethyldioxolane-4-methanol, also known by the trademark is sold and used in the F&F industry, for example for the production of raspberry ketones. Ketones with chain lengths of eleven to 18 carbon atoms are particularly suitable for detergent applications and can be easily derivatized for other target applications, such as, for example, coatings, agrochemicals or household and personal care.

[0003] Several methods involving the manufacture of ketones from acids or acid derivatives in the gas phase or liquid phase have been described in the past. Compared with liquid phase methods, gas phase methods require the use of more complex equipment and catalysts, higher temperatures and therefore higher operating costs. In addition, the productivity of such gas phase methods is generally lower than that of liquid phase methods.

[0004] In the liquid phase, patent applications WO 2016 / 177842, WO 2018 / 087179 or WO 2018 / 033607 disclose a process for the decarboxylation ketonization of fatty acids, the fatty acids being acids in which the number of carbon atoms is greater than or equal to 8, and in which the decarboxylation step is carried out at a temperature strictly greater than 270° C. and up to 400° C. For the production of ketones from carboxylic acids having a boiling point below the process temperature and / or for the production of ketones having a boiling point below the process temperature, these processes cannot be easily implemented because it requires the use of an autoclave operating under pressure while controlling the release of the CO 2 and water formed. The pressure must also be monitored and controlled in order to avoid pressure build-up during the process.

[0005] The present invention provides a new process for the decarboxylation ketonization of volatile carboxylic acids in the liquid phase which overcomes the disadvantages of the prior art. Summary of the invention

[0006] A first aspect of the present invention relates to a process (P) for the decarboxylation of a C2-C8 carboxylic acid, a C2-C8 carboxylic acid derivative or a mixture thereof to the corresponding ketone in the liquid phase, wherein:

[0007] a. gradually feeding the carboxylic acid, carboxylic acid derivative or mixture thereof into a composition (C) comprising at least one metal compound or at least elemental metal as a catalyst and a solvent having a boiling point at least 40° C. higher than the process temperature, and wherein,

[0008] b. The ketone formed is continuously distilled off.

[0009] In a further aspect, the present invention relates to a ketone or a composition of ketones obtainable by process (P) according to the present invention.

[0010] The invention further relates to a composition comprising at least one ketone having a biobased carbon content greater than or equal to 75%.

[0011] In another aspect, the present invention relates to the use of a ketone or a composition of ketones obtainable according to process (P) according to the invention or a ketone or a composition of ketones having a biobased carbon content greater than or equal to 75% as solvent or as starting material (intermediate) for the preparation of compounds useful in the fields of household and personal care, agrochemistry, various industrial processes, coatings, fragrances, veterinary and pharmaceutical applications. DETAILED DESCRIPTION

[0012]

[0026] Throughout this specification, including the claims, the articles "a," "an," and "the" are used to mean that the grammatical object of the article is one or more than one (ie, at least one).

[0013] Throughout this specification, including the claims, the term "and / or" includes the meanings "and", "or" and also all other possible combinations of the elements associated with this term.

[0014] Throughout this specification, including the claims, unless otherwise indicated, the term "comprising one / an" should be understood as being synonymous with the term "comprising at least one / an", and "between..." should be understood as including the limit values. It should be noted that for the sake of continuity of the description, unless otherwise indicated, the limit values ​​are included in the range of the given values.

[0015] The expression “comprises” should be understood to also include “consisting of” or “consisting essentially of”.

[0016] It should be noted that in specifying any numerical range, such as a range of concentration, conversion, or selectivity, any particular upper limit can be associated with any particular lower limit.

[0017] If not otherwise indicated, percentage contents are based on weight.

[0018] In this disclosure, the expressions "biobased materials", "materials of biological origin" or "natural materials" mean products that are composed in whole or in large part of biological products or renewable agricultural materials (including plant, animal and marine materials) or forestry materials.

[0019] In the present disclosure, the expression "biobased carbon" refers to carbon from renewable sources like agricultural, plant, animal, fungal, microbial, marine or forestry materials living in a natural environment in equilibrium with the atmosphere. The biobased carbon content is typically assessed by carbon-14 dating (also known as carbon dating or radiocarbon dating). Furthermore, in the present invention, "biobased carbon content" refers to the molar ratio of biobased carbon to the total carbon of a compound or product. The biobased carbon content may preferably be measured by the following method, preferably according to standard test method ASTM D6866-16, which comprises measuring the disintegration per minute per gram of carbon (or dpm / gC) by liquid scintillation counting. 14 The decay process of C (Carbon 14). The American standard test ASTM D6866 is considered equivalent to ISO standard 16620-2. According to the standard ASTM D6866, the test method can preferably use AMS (Accelerator Mass Spectrometry) and IRMS (Isotope Ratio Mass Spectrometry) techniques to quantify the biobased content of a given product.

[0020] The term "household and personal care" is to be understood as comprising cosmetic formulations (body and hair care formulations) and detergent formulations (laundry detergents, softeners, hard surface cleaners...) or home care formulations (fresheners, air care devices).

[0021] A first aspect of the present invention relates to a process (P) for the decarboxylation of a C2-C8 carboxylic acid, a C2-C8 carboxylic acid derivative or a mixture thereof to the corresponding ketone in the liquid phase, wherein:

[0022] a. gradually feeding the carboxylic acid, carboxylic acid derivative or mixture thereof into a composition (C) comprising at least one metal compound or at least elemental metal as a catalyst and a solvent having a boiling point at least 40° C. higher than the process temperature, and wherein,

[0023] b. The ketone formed is continuously distilled off.

[0024] According to the invention, in process (P), a C2-C8 carboxylic acid, a C2-C8 carboxylic acid derivative or a mixture is used, preferably a C2-C8 carboxylic acid or a mixture of C2-C8 carboxylic acids.

[0025] According to the present invention, C2-C8 carboxylic acid refers to a compound containing 2 to 8 carbon atoms and containing at least one carboxylic acid functional group (-COOH), preferably containing exactly one carboxylic acid functional group. It is further pointed out that according to the present invention, the carbon atoms of the carboxylic acid functional group are included in the C2-C8 carbon atom count. In a preferred embodiment, the carboxylic acid used in method (P) may contain 2, 3, 4, 5, 6, 7 or 8 carbon atoms.

[0026] The C2-C8 chain of the carboxylic acid used in the present invention can be straight or branched, preferably straight, and saturated or unsaturated, preferably saturated. The C2-C8 chain of the carboxylic acid used in the present invention can be optionally substituted, provided that the resulting compound remains stable at the process temperature. As examples of substitution, we can cite halogen or ketone.

[0027] In a preferred embodiment, the C2-C8 carboxylic acid is preferably selected from the group consisting of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, isohexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, 2-ethylhexanoic acid and isooctanoic acid and mixtures thereof.

[0028] According to the present invention, the C2-C8 carboxylic acid is a bio-based C2-C8 carboxylic acid, preferably the bio-based carbon content of the C2-C8 carboxylic acid is higher than or equal to 75%, preferably higher than or equal to 80%, more preferably higher than or equal to 90%. Typically, the bio-based carbon content of the C2-C8 carboxylic acid is lower than or equal to 110%, preferably lower than or equal to 105%, more preferably lower than or equal to 102%, and even more preferably lower than or equal to 100%.

[0029] According to the present invention, C2-C8 carboxylic acid derivatives refer to derivatives of C2-C8 carboxylic acids as described in the present invention. Therefore, the C2-C8 carboxylic acid derivatives used in the method of the present invention can have formula (I) R1-COO-R2 or formula (II) R1-CO-O-CO-R2, wherein R1 comprises 1 to 7 carbon atoms, and wherein R2 is a chain comprising 1 to 8 carbon atoms. R1 and R2 can be straight or branched, preferably straight, and are saturated or unsaturated, preferably saturated. R1 and R2 can be optionally substituted, provided that the resulting compound remains stable at the method temperature. As examples of substitution, we can cite halogen or ketone.

[0030] In a preferred embodiment, the C2-C8 carboxylic acid derivative is preferably selected from the group consisting of acetic acid derivatives, propionic acid derivatives, isobutyric acid derivatives, butyric acid derivatives, hexanoic acid derivatives, isohexanoic acid derivatives, valeric acid derivatives, isovaleric acid derivatives, heptanoic acid derivatives, isoheptanoic acid derivatives, isooctanoic acid derivatives, 2-ethylhexanoic acid derivatives and octanoic acid derivatives.

[0031] According to the present invention, the C2-C8 carboxylic acid derivative is a bio-based C2-C8 carboxylic acid derivative, preferably the bio-based carbon content of the C2-C8 carboxylic acid derivative is higher than or equal to 75%, preferably higher than or equal to 80%, more preferably higher than or equal to 90%. Typically, the bio-based carbon content of the C2-C8 carboxylic acid derivative is lower than or equal to 110%, preferably lower than or equal to 105%, more preferably lower than or equal to 102%, and even more preferably lower than or equal to 100%.

[0032] According to the invention, a C2-C8 carboxylic acid, a C2-C8 carboxylic acid derivative or a mixture thereof is gradually fed into a composition (C) comprising at least one metal compound or at least elemental metal as a catalyst and a solvent having a boiling point at least 50°C higher than the process temperature.

[0033] It will be appreciated that when a single C2-C8 carboxylic acid is used in process (P), a unique symmetrical ketone is obtained as decarboxylated ketonization product. When a mixture of C2-C8 carboxylic acids and / or C2-C8 carboxylic acid derivatives (fractions of C2-C8 carboxylic acids and / or C2-C8 carboxylic acid derivatives) is used in process (P), a statistical mixture of all possible ketones formed by the reaction of different C2-C8 carboxylic acids and / or carboxylic acid derivatives ("composition of ketones") is obtained.

[0034] According to the invention, the catalyst is selected from the group consisting of at least one metal compound or at least one elemental metal. Suitable metals for the process according to the invention are selected from the group consisting of Mg, Ca, Al, Ga, In, Ge, Sn, Pb, As, Sb, Bi, Cd, Ce, Zr and transition metals with an atomic number of 21 to 30. Suitable metal compounds are oxides of the above metals, naphthenates of the above metals or acetates of the above metals. Magnesium and iron and their oxides, and in particular magnesium oxide and iron powder are preferred.

[0035] According to a preferred embodiment, the catalyst is selected from the group consisting of MgO, Fe powder, CaO, TiO2, FeO, Fe2O3, Fe3O4, MnCO3, ZrO2 and CeO2.

[0036] The decarboxylation ketonization reaction can be described as a two-step reaction, wherein in the first step, the catalyst reacts with the C2-C8 carboxylic acid or C2-C8 carboxylic acid derivative to form an intermediate species, followed by a second step in which the intermediate species decomposes into the desired ketone and a metal oxide, which can then react in another decarboxylation ketonization cycle. This second step further produces CO2. Considering the mechanism of the decarboxylation ketonization reaction involving the formation of an ene or enolate, it should be understood that at least one of the C2-C8 carboxylic acids or derivatives participating in the decarboxylation ketonization reaction should have at least one hydrogen atom attached to a carbon atom adjacent to the carboxylic acid functional group -COOH or derivative.

[0037] In the first step of the decarboxylation ketonization reaction, it is further shown that a metal carboxylate is formed as an intermediate substance by the reaction of the catalyst with a C2-C8 carboxylic acid or a C2-C8 carboxylic acid derivative.

[0038] If a single metal is used as a catalyst, the metal reacts with a C2-C8 carboxylic acid or a C2-C8 carboxylic acid derivative to form a metal intermediate carboxylate, while hydrogen is formed in the case of a carboxylic acid. If a metal oxide is used as a catalyst, the formation of the carboxylate is accompanied by the simultaneous formation of water. The overall equation for the formation of the carboxylate (taking a metal with a valence of 2 as an example) can be expressed as follows:

[0039] M+2HCOOR→M(OOCR)2+H2

[0040] MO + 2HCOOR → M(OOCR)2 + H2O

[0041] The formation of the intermediate metal carboxylate can be conveniently monitored by in situ IR analysis. The carbonyl stretching absorption band of the acid becomes red-shifted in the metal carboxylate, which allows the reaction progress to be monitored.

[0042] According to the present invention, the amount of catalyst used in process (P) is generally lower than or equal to 20 wt%, preferably lower than or equal to 10 wt%, still more preferably lower than or equal to 5 wt%, based on the total amount of C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or mixture thereof used in process (P). Typically, the amount of catalyst used in process (P) is comprised between 0.01 wt% and 20 wt%, preferably comprised between 0.01 wt% and 10 wt%, based on the total amount of C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or mixture thereof used in process (P).

[0043] Typically, process (P) is carried out at a temperature ("process temperature") higher than or equal to 250°C, preferably higher than or equal to 270°C, more preferably higher than or equal to 280°C. Typically, process (P) is carried out at a temperature ("process temperature") lower than or equal to 400°C, preferably lower than or equal to 370°C, more preferably lower than or equal to 350°C.

[0044] Typically, process (P) is carried out at atmospheric pressure or below.

[0045] The decarboxylation ketonization process of the present invention is carried out in a solvent in the liquid phase. The solvent used in process (P) is selected from the group consisting of solvents having a boiling point at least 40° C. higher than the process temperature, preferably at least 50° C. higher than the process temperature. The solvent is selected to not react with the catalyst, the ketone product, the intermediate carboxylate, water or the C2-C8 carboxylic acid or C2-C8 carboxylic acid derivative under the process conditions and to be thermally stable at elevated temperatures.

[0046] According to a specific embodiment, the solvent may be a ketone having a boiling point at least 50° C. higher than the process temperature. According to a specific embodiment, the solvent used in process (P) may be a heat transfer fluid, for example from series of heat transfer fluids, especially SH.

[0047] According to a specific embodiment, the solvent used in method (P) can be a ketone, in particular isostearyl ketone, lauryl ketone, myristic ketone, palmitone, stearyl ketone or a mixture thereof or a solvent selected from C 12 -C 18 A mixture of ketones obtained by decarboxylation ketonization of a mixture of saturated fatty acids, such as the fatty acid fractions obtained from coconut oil, palm kernel oil, tallow or palm oil. A preferred solvent for use in process (P) is isostearone.

[0048] According to another specific embodiment, the solvent can be a ketone obtained by a decarboxylation ketonization process of isostearic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, palmitoleic acid or a mixture thereof, preferably isostearic acid.

[0049] According to the present invention, C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or mixture thereof is gradually fed into composition (C). In particular, C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or mixture thereof is fed at a rate to avoid accumulation of free C2-C8 carboxylic acid in the reaction medium.

[0050] For example, a C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or a mixture thereof can be gradually fed into the composition (C) over a period of 1 h to 24 h. In fact, for liquid phase ketonization reactions, it has been unexpectedly observed that the presence of residual free carboxylic acid in the reaction mixture (even at a concentration equal to or lower than 50 mol% relative to the intermediate complex) significantly slows down the decarboxylation kinetics of the intermediate metal complex to the desired ketone. Therefore, it is critical to control the rate at which the carboxylic acid or carboxylic acid derivative (which can generate the free carboxylic acid in situ by hydrolysis) is added so that there is no accumulation of free carboxylic acid (meaning uncomplexed).

[0051] According to the invention, method (P) may result in the formation of a single ketone or a mixture of ketones. Preferably, the ketone formed during method (P) is selected from the group consisting of acetone / propanone, 2-butanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 3-octanone, 4-octanone, 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone, 3-decanone, 4-decanone, 5-decanone, 4-undecanone, 5-undecanone, 6-undecanone, 5-dodecanone, 6-dodecanone, 6-tridecanone, 7-tridecanone, 7-tetradecanone, 8-pentadecanone.

[0052] According to the invention, the ketones formed during process (P) are bio-based ketones, preferably the bio-based carbon content of the ketones is higher than or equal to 75%, preferably higher than or equal to 80%, more preferably higher than or equal to 90%. Typically, the bio-based carbon content of the ketones is lower than or equal to 110%, preferably lower than or equal to 105%, more preferably lower than or equal to 102%, still more preferably lower than or equal to 100%.

[0053] The formed ketone is continuously distilled out. The formed ketone generally has a boiling point below the process temperature. The formed ketone can be continuously distilled and further condensed, for example, by using a distillation or Dean-Stark apparatus. If the formed ketone has a boiling point above the process temperature, the reaction can be carried out under reduced pressure so that the boiling point of the formed ketone is equal to or lower than the process temperature in order to promote ketone distillation.

[0054] During process (P) water is continuously formed. This water may also be continuously distilled from the reaction and may be condensed together with the ketone formed. In the specific case where the ketone formed and water are immiscible, the ketone formed and water may be easily separated by liquid-liquid or solid-liquid separation. Alternatively, in the case where the ketone formed and water are miscible, such as acetone and water, the ketone formed may be separated from the water by any conventional purification method, for example the ketone formed may be distilled from a composition comprising the ketone formed and water, the ketone formed may also be separated from the water by membrane purification or pervaporation.

[0055] The process (P) of the present invention presents several advantages, notably that the process avoids autogenous pressure build-up, is compatible with cheap and available catalysts, and that it avoids the use of expensive equipment. The post-processing of the reaction is simplified: there is no need to separate the catalyst or solvent from the formed ketone, because the formed ketone is continuously distilled from the reaction mixture and is therefore directly separated. The process of the present invention can be used in a continuous mode, thereby improving the overall productivity of the entire process. Finally, catalysts, particularly chromogenic catalysts (like iron oxide) that may cause harmful effects on the ketone product can be advantageously used without harmful effects, because the formed ketone is continuously distilled from the reaction. This is also the case for catalysts that can catalyze ketone decomposition reactions, such as alkaline catalysts like CaO and MgO, which can catalyze the aldol condensation / crotonization side reactions of ketones at high temperatures. These catalysts can now be used in this process without significant yield losses. It can be said in general that this process combines the advantages of liquid phase processes (lower temperatures, standard equipment, cheap catalysts, high productivity, etc. ...) and gas phase processes (easy catalyst / ketone product separation, continuous process ...).

[0056] As mentioned previously, according to a specific embodiment, the solvent can be a ketone obtained by a decarboxylation ketone method. In this specific embodiment, the decarboxylation ketone method (P) of the present invention may include a preliminary step (a0), wherein fatty acid, fatty acid derivatives or mixtures thereof are carried out according to the method described in WO 2016 / 177842, WO 2018 / 087179 or WO 2018 / 033607 Decarboxylation ketone method. Generally, the preliminary step is carried out in the presence of a catalyst, and the catalyst is selected from the group consisting of at least one elemental metal or at least one metallic compound. Suitable metals for the method according to the present invention are selected from the group consisting of Mg, Ca, Al, Ga, In, Ge, Sn, Pb, As, Sb, Bi, Cd, Ce, Zr and transition metals with an atomic number of 21 to 30. Suitable metal compounds are oxides of the above-mentioned metals, naphthenates of the above-mentioned metals or acetates of the above-mentioned metals. Magnesium and iron and their oxides, and particularly iron powder are preferred.

[0057] According to a preferred embodiment, the catalyst is selected from the group consisting of MgO, Fe powder, TiO2, CaO, FeO, Fe2O3, Fe3O4, MnCO3, ZrO2 and CeO2.

[0058] Advantageously, the catalyst used in the preliminary step a0 is the same as the catalyst used in the decarboxylation ketonization of the C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or a mixture thereof, so that no additional catalyst is required. In this case, the crude mixture consisting of the ketone product and the catalyst obtained after the decarboxylation ketonization of the fatty acid, fatty acid derivative or a mixture thereof in step a0 can be used as it is for the decarboxylation ketonization of the C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or a mixture thereof.

[0059] Fatty acid is preferably selected from the group consisting of isostearic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, palmitoleic acid or its mixture. Fatty acid derivatives are usually selected from the group consisting of isostearic acid derivatives, caprylic acid derivatives, capric acid derivatives, lauric acid derivatives, myristic acid derivatives, palmitic acid derivatives, stearic acid derivatives, arachidic acid derivatives, behenic acid derivatives, lignoceric acid derivatives, cerotic acid derivatives, oleic acid derivatives, linoleic acid derivatives, linolenic acid derivatives, erucic acid derivatives, palmitoleic acid derivatives or its mixture.

[0060] Step (a0) is carried out at a temperature higher than or equal to 250° C., preferably higher than or equal to 270° C., more preferably higher than or equal to 280° C. Typically, step (a0) is carried out at a temperature lower than or equal to 400° C., preferably lower than or equal to 370° C., more preferably lower than or equal to 350° C.

[0061] Step (a0) is usually carried out in the liquid phase. However, step (a0) can also be carried out in the gas phase.

[0062] In a further aspect, the present invention relates to a ketone or a composition of ketones obtainable by process (P) according to the present invention.

[0063] The present invention further relates to a ketone or a composition of ketones having a biobased carbon content higher than or equal to 75%, preferably higher than or equal to 80%, more preferably higher than or equal to 90%. Typically, the biobased carbon content of the biobased ketone or the composition of biobased ketones of the present invention is lower than or equal to 110%, preferably lower than or equal to 105%, more preferably lower than or equal to 102%, and even more preferably lower than or equal to 100%.

[0064] In another aspect, the present invention relates to the use of a ketone or a composition of ketones obtainable according to process (P) according to the invention or a ketone or a composition of ketones having a biobased carbon content greater than or equal to 75% as solvent or as starting material (intermediate) for the preparation of compounds useful in the fields of household and personal care, agrochemistry, various industrial processes, coatings, fragrances, veterinary and pharmaceutical applications.

[0065] Examples

[0066] Example 1: Preparation of high boiling point solvent (isostearyl ketone) by decarboxylation ketonization method (step a0)

[0067] The reaction was carried out in a reactor equipped with mechanical stirring under argon. 14.31 g of MgO (0.352 mol, 1 equivalent) and 99.1 g of isostearic acid (Radiacid from Oleon) were introduced into the reactor. TM 0907 grade, 0.352 mol fatty acid, 1 eq.).

[0068] The temperature was then raised to 250°C and stirring was started. During this stage, a magnesium carboxylate complex was formed, while water was produced, which was distilled from the reaction medium. After a reaction time of 40 min at 250°C, FTIR analysis of the crude product showed that the starting isostearic acid was completely converted into an intermediate magnesium dicarboxylate complex. The temperature of the reaction mass was then further raised to 330°C, and the mixture was stirred at this temperature for 3h40, so that the intermediate magnesium complex was completely decomposed into the desired isostearone (and CO2) and MgO, which was tracked by FTIR analysis.

[0069] The temperature of the mixture was then reduced to 310° C. A distillation bridge with a short height and connected to a 250 mL collecting flask was then installed on the reactor vessel in order to distill off the ketone and water formed.

[0070] Example 2: Decarboxylation of hexanoic acid (present invention)

[0071] Into the reactor was introduced the MgO / isostearyl suspension recovered as high-boiling bottoms according to Example 1. Hexanoic acid (0.352 mol) was added under light vacuum (380 mbar) and with stirring at a flow rate of 0.37 mL / min.

[0072] The water formed during the reaction of hexanoic acid with MgO is distilled off from the reaction medium together with 6-undecanone.

[0073] At the end of the hexanoic acid addition, the temperature of the mixture was raised to 315° C. for digestion, during which decomposition of the intermediate complex to the C11 ketone and distillation of the product (with concomitant CO 2 evolution) were observed.

[0074] After 2 h45 of digestion at 315°C, during which the reaction was followed by FTIR analysis confirming consumption of the magnesium complex, two further cycles of 1 equivalent of hexanoic acid addition (2 h00) were performed, followed by 2 h45 of digestion (additional 2 equivalents of hexanoic acid).

[0075] A fourth and final cycle was then performed during which the final distillation was maintained at 315°C for 3h45 in order to complete the decarboxylation of the complex to the C11-ketone, which was verified by FTIR analysis.

[0076] The distillates from the four runs were combined, decanted, and the top organic phase was separated from the aqueous phase.

[0077] The liquid was introduced into a 1 L reactor and dried under vacuum at 60° C. for 6 hours to remove traces of water.

[0078] After drying in vacuo, a clear yellow oil was obtained corresponding to an isolated yield of 89% with a purity of 98 mol% (NMR).

[0079] 1H NMR (CDCl3, 400MHz) δ (ppm): 2.31 (t, J = 7.6 Hz, 4H), 1.54-1.46 (m, 4H), 1.28-1.16 (m, 8H), 0.83 (t, J = 6.8 Hz, 6H).

[0080] 13C NMR (CDCl3, 101 MHz) δ (ppm): 211.75, 42.90, 31.6, 23.70, 22.60, 14.02 (terminal CH3).

[0081] Example 3: Decarboxylation of octanoic acid (present invention)

[0082] The reaction was carried out under inert argon and the reactor was equipped with a mechanical stirrer, a distillation bridge connected to the collector, a heating pad and a temperature probe.

[0083] The MgO / isostearylone suspension recovered as high-boiling bottoms according to Example 1 was introduced into the reactor.

[0084] The suspension contains:

[0085] -500g isostearone (1 mole, 0.5 equivalent)

[0086] - 81 g MgO (2 moles, 1 equivalent).

[0087] 287.5 g of octanoic acid (310.1 mL, 2 moles, 1 equivalent) was added to a 500 mL flask and then inertized under an argon atmosphere. The flask was connected to the reactor via a pump via a stainless steel tube. The reaction mixture was then heated and stirred at 315°C.

[0088] Octanoic acid was then fed into the reactor stepwise, corresponding to the addition of 1 equivalent of octanoic acid during 3 h15.

[0089] During the octanoic acid addition, the temperature of the reaction mass was maintained at 315°C and water was gradually distilled out of the reactor.

[0090] At the end of the octanoic acid addition, the temperature of the reaction mixture was raised to 330° C. during a 30 min digestion phase in order to complete the decarboxylation of the intermediate magnesium complex to the ketone products MgO and CO 2 .

[0091] At this stage, the amount of C15-ketone recovered was lower than the theoretical amount, so a light vacuum (700 mbar) was gradually applied to the reaction vessel in order to promote the distillation of 6-pentadecanone and recover an additional amount of ketone during 25 min.

[0092] The pressure was then raised back to 1 atmosphere and a second addition of octanoic acid (287.5 g, 310.1 mL, 2 moles, 1 eq.) was made at a faster addition rate (2 h30 this time) and at 330° C. During this second addition, the temperature of the reaction mixture was stable and maintained at 330° C. and water as well as the C15 ketone product were distilled steadily from the reactor.

[0093] At the end of the second octanoic acid addition, the reaction mixture was maintained at 330° C. for 15 minutes (digestion phase) in order to complete the ketonization to the intermediate complex of C15 ketone, CO 2 and MgO.

[0094] Finally, the third and final addition of octanoic acid (330.5 g, 356.5 mL, 2.29 moles, 1.15 equiv) was performed at 315° C. with an addition time of 3 h45. During this third addition, the temperature of the reaction mixture was stable and maintained at 315° C. and water and C15 ketone product were distilled very smoothly from the reactor.

[0095] At the end of this last octanoic acid addition, the temperature of the reaction mass was gradually increased to 330° C. in order to complete the ketonization to the intermediate complex of C15 ketone, CO2 and MgO and until no more organic products were distilled from the reactor. In order to recover all the C15 ketone remaining in the reactor, the reaction vessel pressure was reduced to 900 mbar and a strong release of white vapor was observed for a few seconds. The total digestion time after the third carboxylic acid addition was 1 h40.

[0096] Before each carboxylic acid addition cycle, the reaction medium was subjected to FTIR analysis to verify the absence of the intermediate magnesium carboxylate complex, and the organic phase of the distillate was analyzed by 1H NMR to measure the amount of free fatty acids in the distillate. Before each new carboxylic acid addition, the distillate collection vessel was also emptied and the mass of water and C15 ketone collected was determined for each addition cycle after decantation at 50°C.

[0097] After vacuum drying, the C15 ketone was obtained corresponding to 76% isolated yield with a purity of 98.7 wt %. (NMR).

[0098] Example 4: Decarboxylation of acetic acid (present invention)

[0099] 60g Marlotherm SH and 2g of the catalyst as shown in Table 1 are loaded into a 100mL Parr reactor. After closing the reactor, a nitrogen stream of 20mL / min is used to flush the reactor. The reactor is then heated to the reaction temperature and stirred under N2 flow according to Table 1. Acetic acid is then fed into the reactor using a syringe pump with or without nitrogen flow. The outlet of the reactor is connected to a cold bath to collect product. The reaction is carried out for two to three hours.

[0100] The products were analyzed by GC using an internal standard. The results are shown in Table 1.

[0101]

[0102]

[0103] Table 1

Claims

1. A process (P) for the decarboxylation of C2-C8 carboxylic acids, C2-C8 carboxylic acid derivatives or mixtures thereof to the corresponding ketones in the liquid phase, wherein: a. gradually feeding the carboxylic acid, derivative or mixture thereof into a composition C comprising at least one metal compound or at least elemental metal as a catalyst and a solvent having a boiling point at least 40° C., preferably at least 50° C., higher than the process temperature, and wherein, b. The ketone formed is continuously distilled off.

2. The method according to claim 1, wherein: The C2-C8 carboxylic acid, the C2-C8 carboxylic acid derivative or mixture is preferably selected from the group consisting of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, isohexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, 2-ethylhexanoic acid and isooctanoic acid, acetic acid derivatives, propionic acid derivatives, isobutyric acid derivatives, butyric acid derivatives, hexanoic acid derivatives, isohexanoic acid derivatives, valeric acid derivatives, isovaleric acid derivatives, heptanoic acid derivatives, isoheptanoic acid derivatives, isooctanoic acid derivatives, 2-ethylhexanoic acid derivatives and octanoic acid derivatives or mixtures thereof.

3. The method according to any one of claims 1 to 2, wherein: A metal selected from the group consisting of Mg, Ca, Al, Ga, In, Ge, Sn, Pb, As, Sb, Bi, Cd, Zr, Ce and a transition metal having an atomic number of 21 to 30 is used.

4. The method according to any one of claims 1 to 3, wherein: Said process (P) is carried out at a temperature higher than or equal to 250°C, preferably higher than or equal to 270°C, more preferably higher than or equal to 280°C and lower than or equal to 400°C, preferably lower than or equal to 370°C, more preferably lower than or equal to 350°C.

5. The method according to any one of claims 1 to 4, wherein: Water is formed continuously during process (P) and is continuously distilled off from the reaction.

6. The method according to any one of claims 1 to 5, wherein: The C2-C8 carboxylic acid, C2-C8 carboxylic acid derivative or mixture thereof is fed at a rate to avoid accumulation of free C2-C8 carboxylic acid.

7. The method according to any one of claims 1 to 6, wherein: The solvent is a ketone or a heat transfer fluid having a boiling point at least 40°C, preferably at least 50°C, higher than the process temperature.

8. The method according to any one of claims 1 to 7, wherein: The solvent is a ketone obtained by a decarboxylation ketonization process.

9. The method according to any one of claims 1 to 8, wherein: The process (P) comprises a preliminary step (a0), wherein a fatty acid, a fatty acid derivative or a mixture thereof is subjected to a decarboxylation ketonization process, preferably the fatty acid is preferably selected from the group consisting of isostearic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, palmitoleic acid or a mixture thereof, and the fatty acid derivative is preferably selected from the group consisting of isostearic acid derivatives, caprylic acid derivatives, capric acid derivatives, lauric acid derivatives, myristic acid derivatives, palmitic acid derivatives, stearic acid derivatives, arachidic acid derivatives, behenic acid derivatives, lignoceric acid derivatives, cerotic acid derivatives, oleic acid derivatives, linoleic acid derivatives, linolenic acid derivatives, erucic acid derivatives, palmitoleic acid derivatives or a mixture thereof.

10. A ketone or a composition of ketones obtainable according to process (P) as defined in any one of claims 1 to 9.

11. A ketone or a composition of ketones having a biobased carbon content higher than or equal to 75%, preferably higher than or equal to 80%, more preferably higher than or equal to 90%. Typically, the biobased carbon content of the biobased ketones of the present invention is lower than or equal to 110%, preferably lower than or equal to 105%, more preferably lower than or equal to 102%, and even more preferably lower than or equal to 100%.

12. Use of a ketone or a combination of ketones according to claim 10 or 11 as a solvent or as a starting material for the preparation of compounds useful in the fields of household and personal care, agrochemistry, various industrial processes, coatings, fragrances, veterinary and pharmaceutical applications.

Images