Process for the preparation of Ω-amino-carboxylic acids and their derivatives

Abstract

At least one monounsaturated acid / ester CO / H 2 The present invention provides a method for the synthesis of ω-amino acids or derivatives thereof, comprising the steps of: synthesis of ω-oxo esters / linear acids by hydroformylation with a mixture, where the monounsaturated acids / esters are preferably obtained from a metathesis reaction of oils / fats from renewable resources; synthesis of linear ω-amino acids / esters and / or ω-amino amides by subjecting said ω-oxo esters / linear acids to reductive amination; and possible synthesis of linear ω-amino acids by subjecting said linear ω-amino esters and / or ω-amino amides to hydrolysis.

Description

[Technical field]

[0001] The present invention relates to a process for the preparation of ω-aminocarboxylic acids or derivatives thereof and their use in the field of lubricants.

[0002] More specifically, the present invention relates to a method for the preparation of aliphatic ω-amino acids, such as, for example, 11-aminoundecanoic acid or 10-aminodecanoic acid or derivatives thereof, starting from terminal monounsaturated carboxylic acid compounds, such as, for example, 9-decenoic acid or 8-nonenoic acid, preferably for application in the field of lubricants, even more preferably in the field of biolubricants. [Background technology]

[0003] It is known that ω-aminocarboxylic acids or derivatives thereof can be used for applications in the field of lubricants, preferably in the field of biolubricants.

[0004] Lubricants are formulated based on base oil and additives and are used to reduce friction between surfaces in a variety of markets, including automobiles, industrial machinery, and marine machinery. Differences in applications and conditions of use are reflected in differences in chemical formulations (selection and quantity of base oil and additives).

[0005] For example, the literature reports that in addition to the most important application in internal combustion engines, there are a huge number of other applications that often require specific lubricants, with over 90% of all applications requiring 5,000-10,000 different formulations to meet the demand.

[0006] From a volumetric point of view, base oils are the most important component of lubricants, accounting for over 95% of the lubricant formulation; i.e., there are families of lubricants (e.g., some hydraulic and compressor oils) in which chemical additives make up only 1% of the formulation, with the remaining 99% being base oil, whereas some metalworking fluids may contain up to 30% additives (Mang, T., Noll, S., and Bartels, T. (2011). Lubricants, 1. Fundamentals of Lubricants and Lubrication. In Ullman Dictionary of Industrial Chemistry (Ed.). doi:10.1002 / 14356007.a15_423.pub2; Mang, T., Braun, J., Dresel, W. and Omeis, J. (2011). Lubricants, 2. Components. In Ullman Dictionary of Industrial Chemistry (Ed.). doi:10.1002 / 14356007.o15_o04).

[0007] For example, engine lubricants contain numerous additive components, ranging from 5 to 15, typically 8.

[0008] For example, the average composition of an automotive lubricant is 77.6% base, 10.9% viscosity modifier, and 11.5% total additive content by mass. (Source: ATC DOCUMENT 118, August 2016, Table 5 - Publicly available on the Internet: https: / / www.atc-europe.org / public / Document%20118%20%20Lubricant%20Additives%20Use%20and%20Benefits.pdf)

[0009] In this regard, WO 2015 / 027367 teaches that a long-chain compound (polymer) functionalized with two polar groups coordinates the polar groups to each of the respective metal surfaces of a friction pair, while the long chain completely separates the two metal surfaces, thereby preventing them from contacting each other, creating non-abrasive friction and providing excellent anti-wear performance to the lubricating oil, unlike conventional friction modifiers that have a polar group at one end and a non-polar hydrocarbon chain at the other end.

[0010] EP 1151994 refers to novel acid succinimide compounds which can be used as lubricant additives, dispersants for lubricants, friction modifiers for lubricants, detergent additives for liquid fuels.

[0011] Succinimide derivatives are prepared by the reaction of an aliphatic hydrocarbon-substituted succinic acylating agent with an amino acid or a derivative thereof. Amino acids suitable for this purpose include, among others, omega amino acids such as 7-aminoheptanoic acid, 11-aminoundecanoic acid, and 12-aminodecanoic acid. Acid succinimide compounds are prepared by combining a hydrocarbyl-substituted succinic acylating agent with at least one amino acid under suitable operating conditions that can be readily determined by one skilled in the art.

[0012] The patent application does not specify the source or method of preparation of the starting amino acids.

[0013] WO 2008 / 147704 discloses a lubricating composition containing an oil of lubricating viscosity, an oil-soluble molybdenum compound and a low residual antiwear agent. The patent application also relates to a new antioxidant. The lubricating composition may be used in an internal combustion engine. The general formula of the low residual antiwear agent includes an ester of □-aminocarboxylic acid.

[0014] US Patent No. 5,880,072 describes an antiwear composition comprising cyclic amides and monoesters obtained by the reaction of substantially equimolar amounts of a dicarboxylic acid with a polyol, the dicarboxylic acid being a dimer of an unsaturated fatty acid. A preferred cyclic amide is a lactam produced by cyclization and removal of a water molecule from a □-amino acid. The cyclization of amino acids to give lactams is known to those skilled in the art and is reported in reference texts (https: / / en.wikipedia.org / wiki / Lactam).

[0015] The publication, "Tuning the Structure and Ionic Interactions in a Thermochemically Stable Hybrid Layered Titanate-Based Nanocomposite for High Temperature Solid Lubrication" by Gonzalez Rodriguez, P. et al., Adv. Mater. Interfaces 2017, 4, 1700047, describes a new solid organic-inorganic nanocomposite lubricant that synergistically combines the thermodynamically stable structure of layered oxides with the relative flexibility of organic polymers.

[0016] This nanocomposite is a lepidocrocite-type H 1.07 Ti 1.73 It is made by inserting 11-aminoundecanoic acid into the protonated titanate of O4.

[0017] Its use is also known in the manufacture of polyamides and in the production process of polyamide 11 (PA11), where the 11-aminoundecanoic acid monomer is mainly obtained from castor oil.

[0018] From the latter, via subsequent reactions involving thermo-oxidative destruction, bromination and ammonia, the final synthesis of 11-aminoundecanoic acid is obtained.

[0019] However, currently no alternative industrial process has been found that makes it possible to obtain 11-aminoundecanoic acid in good yields starting from sources other than castor oil, although many efforts have been made and, more generally, alternative methods proposed for the synthesis of ω-amino acids are complex and / or give low yields, which in the most favorable cases can be, for example, around 50-60%.

[0020] Indeed, US Pat. No. 8,377,661 describes a method for the synthesis of ω-amino acids or esters thereof starting from natural fatty acids.

[0021] This patent describes a method for the synthesis of amino acids or their esters by converting naturally occurring monounsaturated fatty acids into unsaturated α,ω-diacids or diesters. This occurs by homometathesis or fermentation to produce unsaturated diacids or diesters. The diacids or unsaturated diesters are then subjected to oxidative decomposition at the unsaturation level to obtain the respective acid aldehydes. The acid aldehydes are then converted to amino acids by reductive amination.

[0022] US Patent No. 8,450,509 describes a method for the synthesis of 9-aminonanoic acid or its ester from natural fatty acids. The method for the synthesis of amino acids or amino esters involves starting with a long-chain unsaturated fatty acid or its ester. The fatty acid is subjected to cross-metathesis with ethylene to form an ω-unsaturated acid or ester. The ω-unsaturated acid / ester thus obtained can be subjected to oxidative decomposition to produce an oxo acid / ester, or optionally to homometathesis to obtain an unsaturated symmetrical diacid / diester, which then leads to the formation of an oxo acid / oxo ester by oxidative destruction. The oxo functionality of these compounds, when subsequently reduced, leads to the formation of an amino acid.

[0023] US Patent No. 8,697,401 describes a method for synthesizing amino acids or amino esters from monounsaturated fatty acids or their esters. This patent describes a method for synthesizing amino acids starting from naturally occurring monounsaturated fatty acids or esters. Again, the process is carried out in three stages. In the first stage, the unsaturated fatty acids are converted into unsaturated diacids through a homometathesis reaction. The unsaturated diacids are subsequently converted into unsaturated dinitriles by reaction with ammonia in the presence of a zinc-based catalyst. In the second stage, the unsaturated dinitriles are converted into nitrile acids / esters by oxidative decomposition of the unsaturation with ozone. If necessary, nitrile acids / nitrile esters with two more carbon atoms in the chain can be obtained by cross-metathesis of the unsaturated dinitrile with acrylic acid. In the third stage, the nitrile acids are converted into amino acids by reduction with hydrogen over a nickel Raney.

[0024] US Patent No. 8,835,661 describes a method for the synthesis of C11 and C12 ω-aminoalkanoic acids or esters, which includes a nitrification step. In the initial step, an ester of an ω-unsaturated acid or fatty acid is subjected to nitrification with ammonia in the presence of a niobium-based catalyst, which gives an ω-unsaturated nitrile. By cross-metathesis with an acrylate, the unsaturated nitrile is converted to an unsaturated nitrile ester, which is reduced with hydrogen in the presence of palladium on carbon to form the corresponding amino ester.

[0025] US Patent No. 9,221,745 describes a method for the synthesis of ω-amino acids or long chain esters (6-17 carbon atoms) that involves a cross-metathesis step between an acrylic compound (acrylonitrile, acrylic acid, acrylic acid ester) and another nitrile / unsaturated acid / ester in the presence of a ruthenium carbene compound. The difunctional unsaturated compound (nitrile ester or nitrile acid) thus obtained is subsequently subjected to a hydrogenation process to obtain a saturated amino ester / amino acid.

[0026] US 2014 / 323684 describes a method for preparing saturated or unsaturated ω-amino acids, which includes a hydroformylation step of unsaturated nitriles obtained from the cross-metathesis of fatty acids. The patent application describes the synthesis of amino acids in three steps: a first step of hydroformylation of the unsaturated nitrile, a second step of oxidation of the aldehyde nitrile to give an acid nitrile, and a third step of reduction of the nitrile to give the amino acid. A comparative example using methyl 10-undecenoate reveals that under the given conditions, the hydroformylation of unsaturated nitriles results in better conversion and selectivity to linear products than similar unsaturated esters.

[0027] US 2016 / 0115120 describes a method for the synthesis of aldehydes from unsaturated nitriles / omega esters of fatty acids that specifically controls the hydroformylation and isomerization of the unsaturated nitriles / omega esters of fatty acids. The patent application focuses primarily on describing the parameters used in the hydroformylation reaction to maximize the ratio of linear to branched products.

[0028] US Pat. No. 5,973,208 describes a process for preparing diamines starting from dialdehydes by reaction with ammonia and hydrogen in the presence of a hydrogenation catalyst, an alcohol solvent, and optionally water.

[0029] In fact, as a first approximation, the various traditional synthetic methods for the preparation of ω-amino acids can be divided into two classes: those related to the use of multistep processes that mainly exploit the chemical properties of nitriles, but obtained by direct nitrification of acids or esters or by cross-metathesis with acrylonitrile, and those related to integrated processes that include a step of regiospecific hydrobromination followed by a step of aliphatic nucleophilic substitution of the Br group by NH2.

[0030] Both classes have significant problems: in the first class, nitridation of acids or esters is a process requiring high temperatures, over 250 °C, which highlights the high risk of isomerization of the terminal double bonds, whereas cross-metathesis of unsaturated compounds with acrylonitrile occurs only with low selectivity.

[0031] For the second class, the importance of the latter process lies precisely in the use of hydrobromic acid, which requires corrosion resistance and good performance of the contacting materials, as well as the management of important amounts of inorganic salts containing bromide ions as a by-product of ω-amino acid formation.

[0032] Recently, the development of chemistry from renewable or biological sources has made new precursors available on the market.

[0033] It is therefore desirable to have new and flexible synthetic processes that can use a variety of commercially available sources, for example starting from compounds with different numbers of carbon atoms to arrive at the same ω-amino acid.

[0034] For example, the synthesis of 11-aminoundecanoic acid (the precursor of nylon-11) is usually carried out starting from 10-undecenoic acid by hydrobromination and subsequent amination, but it would be desirable to have a simple and convenient process to obtain the same industrially, produced starting from products such as 9-decenoic acid or its esters, which can be easily obtained from renewable resources by cross-metathesis reaction of unsaturated natural vegetable oils and terminal olefins and which could be available in large quantities on a commercial scale.

[0035] The reactions described in most of the above mentioned patents / patent applications are a combination of cross-metathesis, oxidative decomposition, nitrification, hydroformylation and reductive amination.

[0036] Specifically, among the above mentioned reactions, the oxidative decomposition of unsaturated C=C bonds has particular disadvantages due to the use of toxic ozone as an oxidizing agent and the high production costs. Ozonolysis is an industrial technology applied in pharmaceutical and specialty field production that does not require large quantities.

[0037] In the various syntheses described, preference is always given to the use of fatty acid nitriles to generate the final amino acid, the nitrile, the adjustment of which, as mentioned above, is of considerable importance to the operating conditions.

[0038] Moreover, all the specified steps require intermediate purification and / or separation procedures, although this is not always explicitly stated in the patents / patent applications. Considering the multiple route options, the many parameters involved in the known reactions, and that the conversion of reactants and selectivity to the desired products are not entirely satisfactory, the process as a whole still leaves considerable room for improvement.

[0039] It is therefore an object of the present invention to create an innovative method for the synthesis of aliphatically unsaturated ω-amino acids or derivatives thereof having 5 to 30 carbon atoms, even more preferably having a linear chain, starting from derivatives of linear ω-unsaturated carboxylic acids, preferably esters, more preferably esters of ω-carboxylic acids.

[0040] Specifically, the object of the present invention is to prepare 11-aminoundecanoic acid that can be used for the synthesis of polyamides, starting from methyl 9-decenoate (9-DAME) of renewable origin, limiting the number of intermediate purifications.

[0041] The Applicant therefore posed the problem of finding a method for producing ω-amino acids starting from esters / monounsaturated fatty acids.

[0042] The Applicant has now discovered a process for the preparation of ω-amino acids, which starting from a carboxylic acid compound, preferably a monounsaturated fatty acid ester, comprises in succession the reaction steps of hydroformylation of the monounsaturated compound, reductive amination of the oxo derivative thus obtained, with possible hydrolysis of the ω-amino carboxylic acid compound thus produced to give the desired ω-amino acid, which can finally be subjected to a final step of separation and purification to obtain the product in a form suitable for industrial use. This process can be carried out batchwise or continuously, the continuous mode being preferred.

[0043] Surprisingly, in fact, the applicant has found that the aforementioned reactions can be carried out in succession by carrying out a single final purification step, guaranteeing an acceptable final purity of the desired product and high yield and conversion to the desired product at each intermediate step, without the process causing significant problems or requiring intermediate separation steps of the desired product from other reactions. This embodiment therefore makes it possible to simplify the number of devices used and to significantly reduce the complexity of the overall process. The use of intermediate purification steps can be considered as necessary, where appropriate, to obtain semi-finished products and / or pure chemical intermediates.

[0044] These other objects are surprisingly achieved by the manufacturing method according to the invention.

[0045] Therefore, a first object of the present invention is to provide a compound of formula (III) H2N-CH2CH2-CHR'-(Q)-COR'' (III) or a derivative thereof, comprising the steps of: Starting from an ω-unsaturated carboxylic acid compound having the formula (I), H2C=CR'-(Q)-COR'' (I) R' is H or an aliphatic hydrocarbon group optionally substituted with 1 to 10, preferably 1 to 5, carbon atoms, more preferably H; R'' is OR or NR 1 R 2group, preferably OR, where R is selected from H, ammonium, a monovalent M metal, preferably an alkali metal, a C1-C15 alkyl group and a C6-C15 aryl group, preferably a C1-C5 alkyl group; R 1 and R 2 are independently selected from H, a C1-C15 alkyl group, and a C6-C15 aryl group, preferably a C1-C5 alkyl group; Q is a divalent, aliphatic, optionally substituted, hydrocarbon group having 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, more preferably linear, e.g., a linear heptamethylene group or a linear hexamethylene group; Furthermore, the R' and Q groups may be bonded together to form an aliphatic carbocyclic structure having 5 to 7 C atoms, The process is (A) reacting said compound of formula (I) with a mixture of hydrogen and carbon monoxide under hydroformylation conditions in the presence of a suitable hydroformylation catalyst, preferably containing rhodium or iridium and based on rhodium(I) or iridium(I), preferably based on iridium(I) and a phosphine coupling agent, and optionally a suitable solvent, to produce a compound of formula (II): OHC-CH2-CHR'-(Q)-COR'' (II) obtaining the corresponding ω-oxocarboxylic acid derivative having formula (II), in which R′, R″ and Q have the corresponding meanings as specified above; (B) said compound of formula (II) obtained in step (A), preferably in the absence of an intermediate purification step of the compound of formula (II) from other reaction products, precipitating from the solution by cooling after evaporation of the final solvent, excluding any recovery of the phosphine binding agent used, and excluding the final recovery of the catalyst by one of the methods known to the skilled person, is subjected to a reductive amination by reaction with hydrogen and ammonia in the presence of a suitable catalyst, to obtain the ω-aminocarboxylic acid derivative of formula (III), H2N-CH2-CH2-CHR'-(Q)-COR'' (III) separating it from any reaction solvent; (C) optionally subjecting said compound of formula (III) to hydrolysis to obtain the corresponding ω-amino carboxylic acid, wherein R″ in formula (III) is OH; In order, The objective of the present invention is to provide a method.

[0046] Thus, the ω-amino carboxylic acid of formula (III) and / or its amino derivative of formula (III) synthesized as described above according to the present invention can be As friction modifiers according to those described in WO 2015 / 027367, As low residual antiwear and / or antioxidants in accordance with those described in WO 2008 / 147704, Intercalation into the oxide structure itself, as described by Gonzalez Rodriguez et al. can be used directly as

[0047] Therefore, a second object of the present invention is to constitute a lubricating composition containing as additive or base oil an ω-aminocarboxylic acid of formula (III) and / or a derivative thereof of formula (III), preferably prepared according to the above-mentioned method. In particular, when the ω-aminocarboxylic acid of formula (III) or a derivative thereof prepared according to the above-mentioned method is obtained from an ω-unsaturated carboxylic acid compound (I) of the metathesis reaction of vegetable fats and oils of renewable origin, such as methyl 9-decenoate (methyl 9-decenoate), said composition is a biolubricant, in particular when the ω-aminocarboxylic acid of formula (III) or a derivative thereof prepared according to the above-mentioned method constitutes the base oil (biolubricant) of said lubricating composition.

[0048] In practice, base oil generally comprises the largest proportion of the overall lubricant composition, generally at least 70-80% in internal combustion engine lubricants.

[0049] Preferably, the lubricant according to the present invention should contain at least one percent (1%) of carbon from renewable sources throughout the formulation from components (bases and / or viscosity modifiers and / or additives) from the ω-aminocarboxylic acid or its derivatives of formula (III), and / or at least 25%, preferably 50%, of carbon from renewable sources in a single formulation.

[0050] The carbon content from renewable raw materials is estimated using one of the methods known to those skilled in the art. For example, as reported in the European Union Ecolabel Application Pack for Lubricants - Version 1.0 - September 2011, page 23 / 42, the carbon content of a lubricant is calculated by multiplying the renewable portion of each component (C atoms from plants and animal fats and oils divided by the total number of C atoms (C atoms from plants and animal fats and oils and C atoms from petrochemicals multiplied by the percentage of capacity).

[0051] According to the present invention, the term ω-aminocarboxylic acid means an organic compound containing a carboxyl group -COOH and an aminoethyl group -CH2-CH2-NH2, the carboxylic acid group and the aminoethyl group being separated by at least 2 carbon atoms, preferably at least 4 carbon atoms.

[0052] Preferably, the carboxyl group and the aminoethyl group are linked by a chain of 5 to 15 carbon atoms, more preferably by the formula -(CH2) r - a linear chain of, where r is an integer from 5 to 15, separated by

[0053] According to the invention, the term "derivatives of ω-amino carboxylic acids" refers to derivatives of ω-amino carboxylic acids in which the carboxylic acid group -COOH is a carboxylate group -COOM', M'=ammonium or alkali metal, ester -COOR, amide -CONR 1 R 2 , R, R 1 , and R 2 refers to any compound that can be derived from an ω-carboxylic amino acid, substituted by having the general and preferred meaning given above.

[0054] According to the present invention, unless otherwise specified, the indefinite singular articles a and one are also to be understood as meaning at least one.

[0055] According to the process according to the invention, in step (A) starting from an ω-unsaturated carboxylic acid derivative of formula (I), preferably an ester, more preferably a linear aliphatic carboxylic acid ester, by reacting it with synthesis gas (hydrogen / carbon monoxide mixture) in the presence of a suitable hydroformylation catalyst system, preferably based on rhodium and a bidentate phosphine ligand, a controlled catalytic hydroformylation reaction is carried out to obtain the carboxylic acid ω-oxo derivative of formula (II) in high yield and with a high l / b ratio (linear / branched) (ratio between the desired oxo derivative and its final branched or further branched isomer, if the compound of formula (I) already contains branched alkyl chains).

[0056] The molar ratio of H2 / CO in the synthesis gas is selected by the person skilled in the art according to what is known in the field of hydroformylation of primary olefins, and is preferably 0.3-3, more preferably 0.8-1.3, for example about 1.

[0057] Compared to the prior art, step (A) is distinguished by advantageous operating conditions in terms of the composition of the reaction mixture and the reaction time required to obtain the desired (preferably linear) ω-oxoester product in high yield.

[0058] This reaction is usually carried out at a temperature of 60 to 140° C. under a pressure of 1.5 to 6 MPa for a period ranging from 0.5 to 24 hours, preferably 1 to 3 hours, depending on the substance of formula (I), the temperature and the pressure.

[0059] The reaction can be carried out on the pure compound of formula (I) or in the presence of a suitable amount of organic solvent, preferably 5-90% by weight with respect to the total reaction mixture.

[0060] The organic solvent may be, for example, a polar solvent, such as a straight-chain, branched or cyclic ether, such as methyl tert-butyl ether (MTBE), or an alcohol having 1 to 6 carbon atoms, such as methanol or ethanol, or an aromatic solvent, such as benzene, toluene, xylene, ethylbenzene, or an aliphatic hydrocarbon, such as heptane or cyclohexane.

[0061] Preferably, the solvent is selected from the aforementioned classes of compounds so as to be able to solubilize the phosphine binding agent, the compound of the metal M and the substance of formula (I) itself in the reaction environment.

[0062] Furthermore, the solvent preferably has a lower boiling point than the compounds of formulae (I) and (II) so that it can be at least partially separated therefrom by evaporation.

[0063] Preferred solvents are ethanol, methanol, MTBE and toluene.

[0064] When the organic solvent is an alcohol (such as methanol), at the end of the hydroformylation reaction, a step of acid hydrolysis of the acetal derived from the ω-oxocarboxylic acid compound of formula (II) is preferably carried out, by methods known to those skilled in the art, to give the corresponding aldehyde group.

[0065] According to the process of the invention, all suitable and known catalytic systems, which are available in a large literature, can be used as hydroformylation catalysts.

[0066] In particular, a suitable catalyst for hydroformylation comprises a precursor consisting of a salt or soluble complex of a metal M selected from rhodium, cobalt, iridium, ruthenium, preferably rhodium (Rh) and iridium, more preferably rhodium, and a ligand L, preferably a phosphine binding agent, more preferably an aromatic phosphine, especially a bidentate aromatic phosphine. The metal M in the complex, especially Rh, is preferably in a low oxidation state, for example Rh(I).

[0067] Rh salts which can be commonly used in step (A) of the process of the invention are those commonly used in the art to hydroformylate primary olefinic groups, such as, for example, HRh(CO)(PPh3)3, (acac)Rh(CO)2, [Rh(COD)Cl]2, RhCl(PPh3)3, preferably (acac)Rh(CO)2 (acac = acetylacetonate, COD = 1,5-cyclooctadiene).

[0068] The phosphine ligand L in the hydroformylation catalyst is preferably bidentate (two P atoms per molecule capable of coordinating M) or polydentate (more than two P atoms capable of coordinating M), more preferably bidentate. It may be bound to the metal M in a preformed metal complex and / or may be added to the same reaction environment in which a salt of M, e.g. Rh, is found.

[0069] Preferably, the ligand L, especially if it is a phosphine ligand, is present in a strong molar excess relative to M, preferably in an L / M ratio of 2-40, more preferably 4-20.

[0070] Phosphines which may be used for this purpose include aromatic phosphines and polyphosphines, for example those of the general formula [P(X 1 )(X 2 )(X 3 )] m is a phosphine having the formula X 1 , X 2 and X 3 independently preferably represents an aryl or aryl group, substituted or unsubstituted, and the value of m is greater than 1, and may be linked such that in the case of monophosphines, m=1, in the case of bidentate phosphines, m=2, and in the case of polydenate phosphines, m is greater than 2 (usually 3 or 4).

[0071] Typical bidentate phosphine ligands suitable for the process of the present invention are listed below, and for convenience they are transcribed by their most commonly known English names: BISBI: [1,1'-bis(diphenylphosphinomethyl)-2,2'-biphenyl]; Naphos: [2,2'-bis(diphenylphosphinomethyl)-1,1'-binaphthyl], Xantphos: [4,5-bis(diphenylphosphino)-9,9-dimethylxanthene], BiPhePhos: [6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diyl)bis(oxy)]bis(dibenzo[d,f][1,3,2]dioxaphosphepine)], DPEphos: [bis(2-diphenylphosphinophenyl) ether], DBFphos: [4,6-bis(diphenylphosphino)dibenzofuran].

[0072] Preferred phosphines are in particular Xantphos and BiPhePhos, more preferably having the following structural formula:

[0073] [ka]

[0074] The catalytic molar ratio between the material to be hydroformylated (the compound of formula I) and the metal M, preferably Rh, in the catalyst is between 1,000 and 500,000, but can exceed these limits.

[0075] One of the sensitive aspects of the hydroformylation reaction in step (A) of the present invention is represented by the selectivity towards the ω-oxo derivative product of formula (II) versus products which are isomerized by migration of the olefinic double bond from a primary to an internal one.

[0076] Selectivities of more than 95% are usually obtained using the best catalysts known in the art, with an l / b ratio (linear / branched) of linear molecular compounds greater than 5, preferably greater than 20.

[0077] For example, the hydroformylation of methyl 9-decenoate in toluene, MTBE or methanol with a mixture of CO / H2 = 1:1 (4.5 MPa) in the presence of a catalyst mixture consisting of precursors based on rhodium, (acetylacetonate)dicarbonylrhodium(I), and BiPhePhos, with an ester / Rh ratio of 7500, a BiPhePhos / Rh ratio of 8, and a temperature of 100 °C, leads to a complete conversion of the unsaturated ester, with a yield of 79% of the hydroformylation product and a ratio l / b of linear to branched ω-oxo esters equal to 55 within 2 h of reaction.

[0078] The compound of formula (II) obtained in step (A) may be purified from the reaction mixture in which it is contained (including by-products, the catalyst and / or its residues, the phosphine and any solvent).

[0079] However, the Applicant has surprisingly found that this step of separating and purifying the intermediate compound of formula (II) from other reaction by-products: Possible partial removal of the solvent by evaporation to avoid excessive dilution, Recovery of the binder by precipitation and separation of the phosphine for reuse in the process; recovery of a large part of the catalyst obtained by one of the methods known to the person skilled in the art, for example by distillation of the hydroformylation product from the catalyst or by nanofiltration of the catalyst from the hydroformylation product (as represented in Separation of Homogeneous hydroformylation catalysts using Organic Solvent Nanofiltration, by Waylin Lee Peddie, a thesis presented in partial fulfillment of the requirements for the Master of Engineering degree from Stellenbosch University) or by absorption on an ionic resin in acid form, as described for example in US Pat. No. 5,773,665; which cannot be carried out if the subsequent step is a reductive amination, It has been discovered that the entire reaction mixture can be transferred directly to the reductive amination step (B) without any particular interference, thus avoiding costly separation and purification procedures from hydrogenation and branching by-products.

[0080] In a subsequent stage (B) of the process according to the invention, the ω-oxo derivative of formula (II) obtained from step (A), which is preferably not separated from the reaction mixture except for a possible partial evaporation of the solvent and / or a possible recovery of the phosphine binding agent used and / or a recovery of the catalyst, is subjected to a reductive amination to convert it into the corresponding ω-aminocarboxylic acid derivative of formula (III).

[0081] The reductive amination of step (B) is already known and reported in the literature for a large number of substances and is a reaction widely used for the synthesis of amines starting from aldehydes (see, for example, Morrison, Boyd - Organic Chemistry, pp. 906-908, IV Edition). In US Pat. No. 8,377,661, it is carried out at 100-150 atm hydrogen pressure for 4 hours using Ni Raney as catalyst.

[0082] Reductive amination catalysts suitable for the purposes of the present invention are commercial or synthetic hydrogenation systems based on one or more metals from groups 8, 9 and 10 of the periodic table, such as, for example, iron, cobalt, nickel, or noble metals such as ruthenium, rhodium, palladium, osmium, iridium or platinum, preferably cobalt, nickel, palladium and platinum.

[0083] These catalysts may be used in dispersed phase, colloidal, spongy (e.g. Raney Ni) or supported / bonded phase, preferably in supported / bonded form on an inorganic phase with high surface area, even more preferably on silica, alumina or silica-alumina.

[0084] Thus, according to step (B) of the process, the reductive amination of the compound of formula (II) is carried out using a reduction catalyst based on a metal having hydrogenating properties of groups 8, 9 or 10 of the periodic table, preferably selected from among nickel, cobalt, palladium and platinum, and a mixture of ammonia and H2 in a molar ratio NH3 / H2 of 5 to 25 in the presence of water in a molar ratio H2O / NH3 of 0.01 to 0.25.

[0085] The reaction is carried out with an excess of ammonia relative to the ω-oxo derivative, preferably at a molar ratio of 30-60 NH3 / (compound (II)).

[0086] The reaction temperature is 30 to 200° C., preferably 50 to 150° C., and the pressure is 3 to 15 MPa, more preferably 6 to 9 MPa.

[0087] The reductive amination reaction of the ω-oxoesters can be carried out batchwise (in a reactor equipped with a stirrer, a heating jacket and inlets for the gas and liquid streams) with a reaction time of 0.1 to 3.0 hours, preferably 0.5 to 1 hour. Alternatively, it can be carried out continuously, for example in a tubular reactor equipped with one or more stages. The continuous mode is particularly suited to productivity issues on an industrial scale.

[0088] Reductive amination takes place by reaction of the ω-oxo-derivative (II) with ammonia in the presence of a reduction catalyst under a hydrogen atmosphere.

[0089] The reductive amination reaction may be carried out in the presence of an organic solvent, preferably selected from methyl tert-butyl ether, methanol, ethanol and isopropanol.

[0090] In the preferred case where the compound of formula (II) is a linear ω-oxo derivative, the predominant reductive amination product is the corresponding linear ω-amino derivative (III), which is obtained predominantly for the branched amino derivative.

[0091] The formation of the corresponding aminoamides is observed, of which the most abundant are the linear ω-aminoamides, however these compounds are preferred as they also yield the desired ω-carboxylic acid amino acid at the end of the hydrolysis step (C).

[0092] The ω-amino derivative of the carboxylic acid of formula (III) obtained in step (B) of the process of the invention, unless R″ is already OH, can be subjected to hydrolysis, if necessary, to synthesize the corresponding amino acid, or it can be used as it is, after a purification step by the technique most suitable for the purpose, for example extraction in an aqueous acidic solution of pH 4-7 followed by neutralization.

[0093] On the other hand, when the desired compound is the corresponding ω-amino carboxylic acid, which is a preferred embodiment, the process of the invention is particularly characterized in that in this case R″ in the compound of formula (III) is an ester group or an amide group (R″=OR or R″=NR 1 R 2 , R is alkyl or aryl, and R 1 and / or R 2 is H, alkyl, or aryl), under conditions selected by applicant to optimize the yield of the desired product, and further, without the need to separate the compound of formula (III) from the reaction mixture of step (B).

[0094] The hydrolysis of esters or amides is a reaction widely known in the literature and can be carried out by those skilled in the art in a variety of ways using both alkaline and acid catalysis (Morrison, Boyd - Organic Chemistry, 6th Ed., Par. 20.17-20.18). Therefore, the methods described below refer to the conditions used by the applicant.

[0095] The hydrolysis reaction of the ω-amino derivative of formula (III) with R″ as specified above, preferably linear, is carried out with water in the presence of an acid catalyst such as hydrochloric acid or a basic catalyst such as sodium hydroxide. Basic hydrolysis is preferred.

[0096] Aminoamides can also undergo hydrolysis under the same reaction conditions to give the corresponding amino acids, helping to improve the overall yield of the process.

[0097] The hydrolysis is preferably carried out at elevated temperatures, preferably between 40 and 120 °C, even more preferably at the boiling temperature of the reagent mixture, to continuously remove the alcohol (such as methanol) produced during the hydrolysis of the ester bond and / or the organic solvent used in the previous reductive amination step, and when using a basic catalyst, it is possible to operate in reflux mode with boiling and partial condensation of the vapors.

[0098] The compound of formula (III) is an alkyl amide of an ω-amino carboxylic acid (R 2 =-NR'R''), a basic catalyst is always required.

[0099] The hydrolysis is carried out in a stoichiometric excess of water, which can be ensured by injection from a special line at the beginning or during the reaction. The main product of the hydrolysis is the desired ω-amino acid, preferably a linear amino acid. Depending on the requirements of the end user, the thus obtained, preferably linear ω-amino acid, or a derivative thereof before the hydrolysis step (C), can be separated from the impurity constituted by the corresponding branched isomeric amino acid, for example by fractional crystallization, using one of the methods already known herein. However, very high l / b (linear / branched) ratios can be advantageously obtained by the method of the invention, and according to the requirements of the subsequent use of the product, this separation can in most cases be omitted.

[0100] In prior art patents using nitriles as reagents (e.g., US 2014 / 0323684, US 9,567,293, US 9,096,490), the nitriles are generated by reaction with anhydrous gaseous ammonia at temperatures ranging from 300° C. to 600° C. The resulting nitrile acids / esters subsequently require further reduction reactions with hydrogen to give the corresponding amino acids / amino esters.

[0101] However, in the process of the present invention, it is already possible to obtain the desired amino derivatives / amino acids in a single step at temperatures between 80 and 120° C. by means of the amino reduction step.

[0102] The method according to the present invention is also advantageous with respect to the state of the art of using nitriles, the preparation of which involves the use of hydrogen cyanide.In this case, in practice, no amination is carried out, but it is always necessary to reduce nitriles with hydrogen to obtain corresponding amino acids / amino esters.Moreover, the use of hydrogen cyanide brings about much greater risks than the use of ammonia according to the present invention.

[0103] Preferably, in the process of the invention, no intermediate purification of the reaction mixture obtained in step (A) or (B) is carried out, only a possible solvent evaporation for its recovery and use, as well as a procedure for recovery of the catalyst by one of the methods known to the skilled person.

[0104] In this regard, different solvents may be used, for example toluene in the hydroformylation step and methanol in the second reductive amination step.

[0105] However, applicants have surprisingly identified the possibility of using a single solvent for both reaction steps, further simplifying the process.

[0106] This solvent may be chosen from among the ethers. In particular, the use of methyl tert-butyl ether (MTBE) as the sole reaction solvent in steps (A) and (B) of the process has proven particularly suitable for this purpose.

[0107] In the process of the present invention, all reaction steps and final purification steps may be carried out continuously.

[0108] Specifically, the use of a single solvent for both the hydroformylation and reductive amination reactions further simplifies the process, making it more efficient in terms of productivity and operating costs in a continuous configuration.

[0109] Neither the possibility of using a single integrated process for the synthesis of ω-amino acids starting from ω-unsaturated esters or amides, nor the possibility of using a single solvent for hydroformylation and reductive amination has been described before in any method of the prior art.

[0110] The separation / purification step of the preferably linear ω-carboxylic amino acids following the hydrolysis step (C), when carried out in a basic environment, comprises the acidification of the hydrolysis mixture to a pH value of up to 3-9, preferably 5-7, resulting in the precipitation of the desired product.

[0111] Precipitation with pH correction can be carried out at high, low or room temperature. Low temperature precipitation with refrigeration at 5-10°C is preferred.

[0112] The thus precipitated, preferably linear ω-amino carboxylic acid, is separated from the mother liquor by any liquid-solid separation method suitable for the purpose, such as filtration and / or centrifugation. The purification of the thus separated product is carried out using the usual techniques known to the skilled person, such as subsequent washings. It is preferred to wash first with water and then with an organic solvent. As organic solvent, it is particularly preferred to use acetone or ethyl acetate.

[0113] The product, purified to the desired degree, optionally obtained by repeated washing cycles with water and organic solvents, is finally dried using conventional techniques known to those skilled in the art, such as flushing with inert gas, heating under vacuum or freeze-drying. In a particularly preferred embodiment of the present invention, the applicant has discovered a new and unique process for the production of 11-aminoundecanoic acid starting from methyl 9-decenoate (9-DAME), which is obtained in particular from the metathesis reaction of vegetable oils from renewable sources.

[0114] Thus, although the process according to the invention is described in more detail below with respect to the preparation of 11-aminoundecanoic acid starting from 9-DAME, it is in no way to be understood in a limiting sense to the application of the same process according to the invention using omega-unsaturated carboxylic acid compounds (salts, acids, amides, esters) having different structures and different numbers of carbon atoms within the scope of the above formula (I).

[0115] The mixture of 9-DAME and MTBE solvent is fed continuously with recirculation to a CSTR or tubular reactor after addition of a rhodium-based catalyst and a phosphine binding agent. A preferred solution is based on a CSTR reactor equipped with a device for promoting contact between liquids and gases, for example a liquid jet ejector located at the bottom of the reactor equipped with a circulation pump that feeds the liquid reagent mixture to the ejector and promotes mixing of the reactant phases contained in the reactor. A further preferred solution is to provide two reactors with these characteristics arranged in series. The hydroformylation reaction takes place at a temperature of 60-140°C, preferably 80-120°C, even more preferably 100-110°C, with a residence time of 0.5-24 hours, preferably 1-3 hours. 9-DAME can be fed in the absence of a solvent, but a mixture in a solvent is preferred. The solvent can be present in an amount of up to 90% by weight relative to the total solution, preferably 5-70% by weight relative to the total solution, more preferably 30-60% by weight.

[0116] The gaseous mixture of hydrogen and carbon monoxide (synthesis gas) used in the hydroformylation reaction has a molar composition of 3 parts hydrogen per part carbon monoxide to 1 part hydrogen per 3 parts carbon monoxide, preferably 1 part hydrogen to 1 part carbon monoxide. The pressure of the synthesis gas under which the reaction is carried out is 1.5-6 MPa (15-60 bar), preferably 3-5 MPa.

[0117] Preferably, the hydroformylation catalyst is an organometallic rhodium complex prepared in situ by reaction of a precursor of rhodium, preferably (acetylacetonato)dicarbonylrhodium(I), with a precursor of a bidentate phosphine ligand, preferably BiPhePhos (BiPhePhos refers to the molecule "6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diyl)bis(oxy)]bis(dibenzo[d,f][1,3,2]dioxaphosphepine)" having a molecular weight of 786.78 Da). The molar ratio of 9-DAME to the rhodium precursor is 2,500-20,000, preferably 5,000-15,000. The molar ratio of the bidentate phosphine ligand to the rhodium precursor is preferably 2-40, more preferably 4-20.

[0118] The main hydroformylation products, linear ω-oxo esters, are obtained in yields up to 80%. Conversions of unsaturated esters are between 73 and 99.9%, the selectivity for hydroformylation products (linear, more branched) is between 60 and 99%, and the selectivity for linear hydroformylation products (linear / total ratio of branched hydroformylation products, expressed as l / b) is greater than 25.

[0119] All conversion, selectivity and yield values ​​mentioned refer to values ​​determined by gas chromatographic analysis of the reaction mixture in the presence of an internal standard as described in the examples (internal standardization).

[0120] The reactor exit stream is depressurized in a gas-liquid separator and the liquid fraction is cooled in order to recover part of the phosphine binding agent which separates as a solid from the liquid stream (possibly with partial heat recovery). Separation of the solids can be conveniently carried out in a gravity separator or a centrifuge. A set-up based on a continuous horizontal centrifuge is the preferred set-up. The clarified liquid phase is sent to the next stage of separation of the desired products, while the solids are recycled as feed to the hydroformylation reactor. In this way, the phosphine binding agent can be recovered and reused in the process.

[0121] The clarified liquid stream may optionally be fed to an evaporator to recover the solvent and unreacted 9-DAME. Any type of evaporator known in the art may be advantageously used for the purposes of the present invention. Preferably, a "kettle" type evaporator is used. Details of the types of evaporators that can be used for this purpose are described, for example, in Perry's Handbook of Chemical Engineers, McGraw-Hill (7th Edition - 1997), section 11, pages 108-118. Another setup is based on the use of a flat or packed distillation column. The use of a distillation column allows the recycling of the solvent and unreacted 9-DAME, and results in a lower content of the products of the hydroformylation reaction than when an evaporator is used.

[0122] The liquid stream leaving the evaporator or from the bottom of the distillation column containing the hydroformylation product and the catalyst can partly be recycled to the hydroformylation to recycle the catalyst and partly sent to a catalyst removal section, which can be carried out using one of the methods known in the literature and to the person skilled in the art, such as, for example, the methods described in U.S. Pat. No. 5,773,665 (ELF Atochem) or U.S. Pat. No. 6,946,580 (Davy process Technologies).

[0123] The liquid stream, from which the catalyst and binder have been removed, is then sent to an exchanger and heated to a temperature between 30° C. and 200° C., preferably between 80° C. and 140° C., more preferably between 100° C. and 110° C. The current from the exchanger is sent to a reactor for the reductive amination reaction. The reactor is preferably in a fixed bed, more preferably in a "trickle bed" configuration, and is heated for 1 to 50 hours. -1 , preferably 3 to 10 hours -1 The reactor is operated at a WHSV (weight hourly space velocity for the total reagent mixture) of 10 ...

[0124] The reductive amination reaction may be carried out in the presence of an organic solvent, preferably selected from among methyl tert-butyl ether, methanol, ethanol and isopropanol. Methyl tert-butyl ether is preferred. The solvent may be present in an amount of 5% to 90% by weight relative to the reaction mixture, preferably 30% to 70% by weight, more preferably 50% by weight relative to the reaction mixture.

[0125] The reductive amination reaction is preferably carried out in the presence of 2-10% by weight of water relative to the ammonia. The reactor is also fed with H2 at a maximum pressure of 0.3-30 MPa (3-300 bar), preferably 3-15 MPa (30-150 bar), more preferably 6-9 MPa (60-90 bar). The reactor is kept flushed with gas by recycling the gas leaving the reactor head to the bottom of the reactor by a compressor / fan. A portion of fresh ammonia is continuously fed to maintain the molar ratio specified above. A portion of recovered H2 is fed to maintain the pressure value specified above. A stream consisting of a mixture of reaction products and possibly solvent emerges from the bottom of the reactor. A preferred set-up of this reactor involves recycling excess gas, especially ammonia, through the use of a liquid jet ejector installed at the top of the "trickle bed" type reactor. The feed liquid is the same reaction mixture recycled through a pump.

[0126] The main product of the reductive amination is the linear ω-amino ester (methyl 11-aminoundecanoate), the main by-products are the reductive amination product of the aldehyde group and the contextual amidation of the ester group, i.e., the ω-amino amide. However, this compound is interesting because it also produces the desired ω-amino acid at the end of the subsequent hydrolysis step. The ω-oxo ester conversion is quantitative, with a selectivity towards amino esters higher than 88% and towards the aminated amidation product (ω-amino amide) less than 12%. All mentioned conversion, selectivity and yield values ​​refer to those determined by gas chromatographic analysis of the reaction mixture in the presence of an internal standard.

[0127] The current can be suitably sent to a system for recovering the dissolved ammonia and the solvent. A preferred set-up is based on a degasser which the reaction mixture undergoes after it has been depressurized to 0.1-2.0 MPa (1÷20 bar), preferably 0.3-0.8 MPa (3÷8 bar), even more preferably 0.4 MPa-0.6 MPa (4÷6 bar), where most of the dissolved ammonia and part of the solvent pass into the vapor phase and are partially evaporated. The liquid leaving the degasser is fed to an evaporator to recover the solvent. The reaction mixture, containing traces of solvent, leaves the bottom of the evaporator. The vapor from the evaporator is fed to the degasser. The degasser contains several perforated plates that facilitate the separation and contact of the two phases, the liquid phase and the vapor phase. The vapour phase leaving the degasser is partially condensed in a first condenser of reflux type operating at a temperature between 20 and 250° C., preferably between 80 and 150° C., more preferably between 105 and 130° C., and then in a post-condenser operating at a temperature between −75 and 80° C., preferably between −20 and 30° C., more preferably between −5 and 15° C. The liquid collecting at the outlet from the condenser is the recycled solvent, whereas the liquid leaving the post-condenser consists mainly of ammonia, which is then also recycled.

[0128] The mixture leaving the evaporator can be sent to the hydrolysis stage (C), but in a preferred configuration is sent first to a further degasser at a pressure of 10-400 kPa absolute, preferably 50-250 kPa, for example 80 kPa absolute. In this further degasser the residual solvent content is reduced to less than 1% by weight, preferably less than 0.1% by weight, even more preferably less than 0.01% by weight. The vapours separated in this degasser are condensed at a temperature of -75-80°C, preferably -20-30°C, even more preferably -5-15°C, and then recycled to the first degasser. The hydrolysis of esters is a reaction known in the literature and can be carried out by the skilled person in various ways. The methods specified below therefore refer to the conditions used by the applicant and are in no way to be considered as limiting the method of the present invention.

[0129] The hydrolysis is carried out continuously in a reactor, called hydrolyzer, preferably of CSTR type, fitted with a heating system and a condensation system formed by a partial reflux condenser that recycles the water in the hydrolyzer and a post-condenser that condenses most of the methanol produced and constituting a by-product of the process, in the presence of a basic catalyst, preferably sodium hydroxide or potassium hydroxide, with a residence time of 0.5 to 12 hours, preferably 2 to 6 hours. If necessary, the pH of the solution is maintained at a value above 12 by adding NaOH or KOH. The hydrolysis is carried out at high temperature, preferably at the boiling point of the mixture. The hydrolysis product leaves the bottom of the reactor, the main product being ω-linear amino acids, more predominantly obtained than branched amino acids. If necessary, the solution leaving the hydrolysis reactor can be sent to a static separator, thermostated at the hydrolysis temperature first. A part of the by-products is removed from the top of the separator. An aqueous stream is obtained from below and sent to the separation section of the desired product by precipitation / crystallization.

[0130] To the water stream containing the desired hydrolysis product, an acid is added to adjust the pH to a value between 3 and 9, preferably between 5 and 7. The acid can be HCl or acetic acid, anhydrous or in solution. HCl solution is preferred. The solution is cooled to a temperature between 2 and 20°C, preferably between 5 and 10°C, and then sent to a mixing tank where the product forms a precipitate which is retained in the liquid phase and forms a cloudy mixture or "slurry", which is subsequently sent to a filtration and washing system of the solids formed by the Ω-linear amino acids which constitute the end product of the process.

[0131] The purification of the ω-amino acids after such separation can be carried out using the usual techniques known to those skilled in the art. For example, it can be carried out by recrystallization, washing with one or more liquids in which it is poorly soluble, electrophoresis, etc. For example, the ω-linear amino acids can be purified by cold washing first with water and then with an organic liquid in which it is poorly soluble (preferably with a solubility of less than 1 g / l), for example a ketone such as acetone or butanone, an alcohol such as methanol or ethanol, an ester such as ethyl acetate, butyl acetate, etc. Acetone and ethyl acetate are preferred. The white solid obtained is conveniently dried by one of the known techniques suitable for the purpose, such as flushing with an inert gas, heating under vacuum, or freeze-drying.

[0132] The organic wash liquid is distilled and collected in the column, and high boiling compounds and impurities are obtained from the top and bottom of the column. For the crystallization / precipitation and filtration operations, it is possible to use those already existing in the prior art, such as those in the literature articles of Industrial & Engineering Chemistry Research, 2016, 55, 7462-7472 or American Institute of Chemical Engineers (AIChE) Journal, 1991, 37(8), 1121-1128.

[0133] The purity of the linear ω-amino acids is determined by gas chromatographic analysis (GC-FID) after silylation of the product according to one of the methods known to those skilled in the art.

[0134] As mentioned above, the ω-aminocarboxylic acid of formula (III) or a derivative thereof of formula (III) obtained by the process of the present invention may be conveniently used for the preparation of lubricating compositions, for example according to methods known in the art for use in the ω-aminocarboxylic acid itself, or in compounds derived therefrom, such as oligomerization, cyclization (e.g. lactam formation), and by other functionalization reactions described in the art, such as reaction with succinic acylant substituted with an aliphatic hydrocarbon group.

[0135] Examples of derivative compounds which may be advantageously obtained from the ω-aminocarboxylic acids according to the invention contain 11-aminoundecanoic acid derivatives as characteristic moieties and may be, for example, the compounds S-acid-8, S-acid-6, S-amide 1, S-amide 5, S-amide 9, S-amide 10, S-ester 7, S-ester 8, S-ester 4, which are already recognised in the art as lubricants or lubricant additives, as described in EP 1 151 994.

[0136] A further object of the present invention therefore constitutes a method for the preparation of a lubricating or biolubricating composition, comprising preparing an ω-aminocarboxylic acid of formula (III) or a derivative thereof of formula (III) according to the method previously described, plus an additional subsequent step of introducing said ω-aminocarboxylic acid, its derivative of formula (III), or a further derivative of one of the above (e.g. oligomerized and / or cyclized compounds starting from the derivative of formula (III)) in a composition comprising at least one lubricating base stock (base oil).

[0137] The present invention will now be further illustrated in the following examples, which are offered by way of illustration only and do not in any way limit the invention described and claimed herein. EXAMPLES

[0138] In the examples below, the following abbreviations and references are used unless otherwise specified: Syngas (a gaseous mixture of hydrogen and carbon monoxide in a 1:1 molar ratio in a pressurized cylinder): prod. SAPIO, IT, Methyl 9-decenoate (9-DAME): purity >98%, prod.Elevance (Clean® 1000), (CAS 25601-41-6), (Acetylacetonato)dicarbonylrhodium(I) ((acac)Rh(CO)2): 98% purity, prod. Aldrich, cod. 288101 (CAS 14874-82-9, PM=258.03Da); 6,6'-[(3,3'-di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diyl)bis(oxy)]-bis(dibenzo[d,f][1,3,2]dioxaphosphepine (BiPhePhos): purity: 97%, prod. Aldrich, cod. 699535 (CAS 121627-17-6, PM=786,78Da); Methyl tert-butyl ether (solvent, MTBE): 99.8% purity, prod. Sigma-Aldrich; Toluene: 99.8% purity, prod. Sigma-Aldrich; Methanol: purity 99.8%, prod. Sigma-Aldrich; Acetone: 99.8% purity.

[0139] (Gas Chromatography Analysis) Gas chromatographic analysis for the quantification of reagents and products of hydroformylation and reductive amination reactions is performed using an Agilent 7890B gas chromatograph equipped with a flame ionization detector with a split / sprayless injector and a HP-1 column (100% polydimethylsiloxane, Agilent J&W) fused silica WCOT, length 25 m, ID 0.20 mm, film thickness 0.33 μm, carrier gas H2, 0.8 ml / min, constant flow, 500:1 split ratio, temperature injector 300 °C, detector temperature 330 °C, oven temperature program 40 °C-8 °C / min, maximum 320 °C.

[0140] Quantification is performed with the internal standardization method by measuring the response factors of the available components to n-dodecane (internal standard).

[0141] Analyze the samples by weighing out 0.5 g of sample accurately, always to a precise volume, and adding to a 2 mL vial a solution of approximately 3000 ppm n-dodecane in chloroform to a constant volume.

[0142] The given example refers to batch mode (for ease of experimentation), but it is also representative of the corresponding continuous process.

[0143] (Example 1: Hydroformylation of 9-DAME with Syngas in MTBE) Ester molar ratio / Rh=5065, L molar ratio (phosphinic acid) / Rh=16.

[0144] In a 500 ml autoclave equipped with a mechanical stirrer, a heating jacket, and a gas inlet, 70 ml of the MTBE solution containing 102 g (0.542 mol) of 9-DAME, 28.3 mg (0.107 mmol) of (acac)Rh(CO)2, 1381 mg (1.703 mmol) of BiPhePhos, previously prepared in an inert atmosphere, is introduced and stirred under a nitrogen stream for 1 h, followed by the introduction of approximately 60 ml of MTBE.

[0145] The autoclave is flushed twice with synthesis gas, then pressurized to 3.0 MPa at room temperature and brought to a temperature of 100° C., with stirring, so that the pressure inside the reactor is approximately 5.0 MPa.

[0146] The reaction is allowed to continue for 2 hours, at the end of which the reactor is cooled and the liquid reaction mixture is discharged and maintained under a nitrogen atmosphere.

[0147] From the gas chromatographic analysis carried out in the presence of an internal standard, it is observed that the conversion of 9-DAME is 99.9%, the selectivity towards hydroformylation products (oxoesters) is 76%, and the l / b ratio between methyl 11-oxoundecanoate (ω-oxoester) and the sum of its branched isomers is equal to 53.

[0148] Example 2: Reductive amination of methyl 11-oxoundecanoate In a 250 ml autoclave equipped with a mechanical stirrer, a heating mantle, a basket for the catalyst and a gas inlet, 30 g of a cobalt-based hydrogenation catalyst supported on alumina (HTC Co 2000 RP 1.2 mm, 15% Co supported on alumina, commercial product Johnson Matthey Chemicals GmbH, D - data from US Pat. No. 8,293,676, Table 3, columns 21-22, example J) are placed in a dedicated catalyst holder and activated in a hydrogen atmosphere.

[0149] Activation of the catalyst is first performed by flowing nitrogen at atmospheric pressure, then the reactor is heated with a temperature increase of 25-50°C / h up to a maximum of 150°C, and once this temperature is reached, hydrogen is fed at a flow rate of 30 ml / min and the temperature is increased to 180°C.

[0150] At this point, the hydrogen flow rate is increased by gradually decreasing the nitrogen flow rate until the gas flushing is entirely hydrogen based (flow rate 200 ml / min). Activation is allowed to continue for 18 hours under these temperature and flow conditions, after which the nitrogen flow is restored (with simultaneous reduction in the hydrogen flow) to keep the catalyst in an inert atmosphere, and the system is gradually cooled to room temperature.

[0151] The hydrogen is then discharged and 58 g (3.41 mol) of ammonia gas is introduced. The reactor is again pressurized with gaseous hydrogen up to 3.8 MPa, then 57.8 g of the liquid reaction mixture obtained in Example 1 above, containing 42% (24.3 g, 113.3 mmol) of methyl 11-oxoundecanoate, is charged into it, to which 58 g of MTBE and 4.7 g of water are added (8% by weight relative to ammonia). The autoclave is then heated to 100° C. with stirring until a pressure of 8.9 MPa is reached. Once the desired temperature is reached, the reaction is continued for 1 hour before cooling and removal from the autoclave.

[0152] Gas chromatographic analysis performed on the reaction crude in the presence of an internal standard shows a conversion of methyl 11-oxoundecanoate and other oxoesters to the corresponding reductive amination products of 99%. Of these, 98% are aminoesters, while the products of reductive amination and contextual amidation (aminoamides) amount to 2%.

[0153] The saturated ester obtained in the first hydroformylation step remains as a by-product and is partially converted to the corresponding saturated amide.

[0154] Example 3: Hydrolysis of the mixture of amino esters and amino amides of Example 2 and purification of the resulting 11-amino-undecanoic acid. A 500 ml flask equipped with a stirrer, a heating mantle and a reflux condenser was charged by vacuum deposition with 35 g of a mixture of aminoesters and aminoamides in MTBE, containing 50.8% by weight of methyl 11-aminoundecanoate, obtained by removing part of the solvent (MTBE) starting from the reaction crude product of Example 2, to which were added about 300 ml of water and 45% NaOH until a pH of 12 was reached.

[0155] The mixture is heated to boiling temperature with stirring and left under these conditions under reflux for 6 hours. After completion of hydrolysis, the mixture is cooled and hydrochloric acid is added to bring the pH back to a value of 6.

[0156] A white precipitate was observed to form, which was allowed to settle overnight on cooling. The solid was isolated by vacuum filtration in a Buchner funnel and washed repeatedly with water and small amounts of cold acetone.

[0157] 11-Aminoundecanoic acid (12.7 g) is obtained as a very fine white solid, characterized by proton and carbon-13 nuclear magnetic resonance analysis. The melting point is 181-183°C. The calculated molar yield with respect to the linear amino ester (methyl 11-aminoundecanoate) is 76%.

[0158] Example 4: Hydroformylation of 9-DAME in Methanol Using Syngas In a 500 ml autoclave as used in Example 1 above, 25.4 g (0.135 mol) of 9-DAME are introduced into 210 ml of methanol and a solution containing 4.9 mg (0.0186 mmol) of (acac)Rh(CO)2 and 118 mg (0.145 mmol) of BiPhePhos in 10 ml of methanol, previously prepared in an inert atmosphere and kept stirring under a nitrogen stream for 1 hour. The autoclave is flushed twice with synthesis gas, pressurized up to 4.5 MPa with stirring and the temperature is increased to 100 °C. The reaction lasts for 2 hours, at the end of which the reactor is cooled and the reaction mixture is discharged.

[0159] From the gas chromatographic analysis carried out in the presence of an internal standard, a 9-DAME conversion of 99.9%, a selectivity towards hydroformylation products (oxoesters in the form of both free aldehydes and dimethyl acetals) of 80% and an l / b ratio between the linear compounds (methyl 11-oxoundecanoate + methyl 11,11-dimethoxy-undecanoate) and the sum of the corresponding branched isomers equal to 44 are observed.

[0160] The dimethyl acetals can be converted to the corresponding oxoesters by acid hydrolysis of the reaction crude at reflux at pH 1 for 3 hours.

[0161] Example 5: Hydroformylation of 9-DAME with Syngas in MTBE Ester molar ratio / Rh=4970, molar ratio L / Rh=16.

[0162] In a 500 ml autoclave as used in Example 1 above, 25.5 g (0.1356 mol) of 9-DAME, 35 ml of a solution of MTBE containing 7.2 mg (0.0273 mmol) of (acac)Rh(CO)2 and 349 mg (0.430 mmol) of BiPhePhos previously prepared in an inert atmosphere and kept under stirring under a nitrogen flow for 1 hour, and about 185 ml of MTBE are introduced. The autoclave is flushed twice with synthesis gas, pressurized up to 30 bar at room temperature and brought to 100° C. (the temperature at which the pressure in the reactor is about 50 bar) with stirring. The reaction lasts for 2 hours, at the end of which the reactor is cooled, the liquid reaction mixture is discharged and it is kept under a nitrogen atmosphere.

[0163] From the gas chromatographic analysis carried out in the presence of an internal standard, a conversion of 9-DAME of 99.9%, a selectivity towards hydroformylation products (oxoesters) of 71%, and an l / b ratio between methyl 11-oxoundecanoate (ω-oxoester) and the sum of its branched isomers equal to 55 are observed.

[0164] Example 6: Reductive amination of methyl 11-oxoundecanoate A 250 ml autoclave as used in Example 2 above is charged with 56 g (3.29 mol) of ammonia gas at room temperature in the presence of 30 g of a nickel-based hydrogenation catalyst supported on silica-alumina (Ni-3288E1 / 16 inch 3F, about 60% Ni, commercial product of Engelhard De Meern BV, New Jersey) placed in a dedicated catalyst holder and preactivated in a hydrogen atmosphere as already described in Example 2 above for the cobalt hydrogenation catalyst. The reactor is pressurized with gaseous hydrogen up to 3.8 MPa (38 bar) and then, after removing part of the reaction solvent (MTBE) by vacuum evaporation, 67.6 g of a mixture of oxoesters containing 26.2% by weight (17.7 g, 82.9 mmol) of methyl 11-oxoundecanoate obtained as described in Example 5 above are introduced. 45 g of MTBE and 4 g of water are also fed (7% by weight relative to ammonia).

[0165] At the end of the charge of the oxoester solution in MTBE, the autoclave is heated with stirring to 108° C. until a pressure of 84 bar is reached. Once the desired temperature is reached, the reaction is continued for 60 minutes (1 hour) before cooling and removing from the autoclave.

[0166] From the gas chromatographic analysis carried out on the reaction crude product in the presence of an internal standard, complete conversion of methyl 11-oxoundecanoate and other oxoesters to the corresponding reductive amination products is observed. Of these, 98% are amino esters, while the amount of products of reductive amination and contextual amidation (aminoamides) is 2%. The saturated esters obtained in the first hydroformylation step remain as by-products and are partially converted to the corresponding saturated amides.

[0167] Example 7: Hydroformylation of methyl 9-decenoate with synthesis gas in toluene T = 100 °C, synthesis gas pressure = 4.5 MPa, ester / Rh molar ratio = 5000, L / Rh molar ratio = 16.

[0168] In a 500 ml autoclave as used in Example 1 above, 25 g (0.133 mol) of methyl 9-decenoate are placed in 220 ml of dry toluene and a solution containing 7 mg (0.0266 mmol) of (acac)Rh(CO)2 and 345 mg (0.425 mmol) of BiPhePhos in toluene, previously prepared in a dry box and stirred under nitrogen for 1 h. The autoclave is flushed twice with synthesis gas, then pressurized up to 4.5 MPa and brought to a temperature of 100 ° C. with stirring. The reaction lasts for 2 hours, at the end of which the reactor is cooled and the reaction mixture is discharged.

[0169] From the gas chromatographic analysis carried out in the presence of an internal standard, a conversion of 99.9% of methyl 9-decenoate, a selectivity towards hydroformylation products (oxoesters) of 71% and l / b of methyl 11-oxoundecanoate (ω-oxoesters) and the sum of its branched isomers equal to 66 are observed.

[0170] Example 8: Reductive amination of methyl 11-oxoundecanoate in the presence of water, feeding the oxoester into a reactor already pressurized with hydrogen. A 250 ml autoclave as used in Example 2 above is charged with 88 g (5.17 mol) of ammonia gas at room temperature in the presence of 30 g of a nickel-based hydrogenation catalyst supported on silica-alumina (Ni-3288E1 / 16 inch 3F, about 60% Ni, commercial product of Engelhard De Meern BV, NL) placed in a dedicated catalyst holder and preactivated in a hydrogen atmosphere. The reactor is pressurized up to 3.4 MPa (34 bar) with gaseous hydrogen and then, after removing most of the reaction solvent (toluene) by evaporation under vacuum, 32 g of the reaction mixture obtained in Example 7, containing 57% by weight (18.2 g, 85.1 mmol; ammonia / oxoester ratio=60) of methyl 11-oxoundecanoate, is fed to it, together with the addition of 93 g of methanol and 4.7 g of water (5.3% by weight relative to ammonia).

[0171] Once the charging of the methanolic oxoester solution is complete, the autoclave is heated with stirring to 108°C until a pressure of 82 bar is reached. Once the desired temperature is reached, the reaction is allowed to continue for 60 minutes before cooling and removing from the autoclave.

[0172] From the gas chromatographic analysis carried out on the reaction crude product in the presence of an internal standard, the complete conversion of methyl 11-oxoundecanoate and other oxoesters to the corresponding reductive amination products is observed. Of these, 88% are amino esters, while the amount of reductive amination and contextual amidation (aminoamide) and products is 12%. The saturated esters obtained in the first hydroformylation step remain as by-products and are partially converted to the corresponding saturated amides.

[0173] Example 9: Hydrolysis of methyl 11-amino-undecanoate from Example 8 and purification of the resulting 11-amino-undecanoic acid A 500 ml flask as used in Example 3 above is charged with 26.2 g of a methanolic mixture of aminoesters and aminoamides obtained by removing part of the solvent (methanol) starting from the reaction crude product of Example 8, containing 50% by weight of methyl 11-aminoundecanoate, by vacuum evaporation, to which are added about 300 ml of water and 40% NaOH until a pH of 12 is reached. The mixture is heated to boiling temperature with stirring and left under these conditions under reflux for 6 hours. After completion of the hydrolysis, the mixture is cooled and hydrochloric acid is added to bring the pH back to a value of 6.

[0174] A white precipitate was observed to form, which was allowed to cool and settle overnight. The solid was isolated by vacuum filtration through a Buchner funnel and washed repeatedly with small portions of cold acetone.

[0175] 11-Aminoundecanoic acid (10.4 g) is obtained as a very fine white solid, characterized by proton and carbon-13 nuclear magnetic resonance analysis. The melting point is 180-184°C. The calculated molar yield with respect to the linear amino ester (methyl 11-aminoundecanoate) is 85%.

[0176] Tables 1 and 2 show summary data for the above examples.

[0177] Finally, it is understood that further modifications and variations not specifically mentioned herein may be made to the processes described and illustrated herein, but which should be considered as obvious variations of the invention within the scope of the appended claims.

[0178] [Table 1]

[0179] [Table 2]

Claims

1. A process for the preparation of an ω-aminocarboxylic acid of formula (III) or a derivative thereof, comprising starting from an ω-unsaturated carboxylic acid compound having formula (I): H ２ C=CR’-(Q)-COR’’ (I) R' is H or an aliphatic hydrocarbon group optionally substituted with 1 to 10, preferably 1 to 5, carbon atoms, more preferably H; R'' is OR or NR １ R ２ group, preferably OR, where R is selected from H, ammonium, a monovalent M metal, preferably an alkali metal, a C1-C15 alkyl group, and a C6-C15 aryl group, preferably a C1-C5 alkyl group; R １ and R ２ are independently selected from H, a C1-C15 alkyl group and a C6-C15 aryl group, preferably a C1-C5 alkyl group; Q is a divalent, aliphatic, optionally substituted hydrocarbon group of 1 to 12 carbon atoms, preferably 3 to 10 carbon atoms, more preferably straight chain, e.g., straight chain heptamethylene or straight chain hexamethylene; Additionally, the R′ and Q groups may be joined together to form an aliphatic carbocyclic ring structure having 5 to 7 carbon atoms; The process is (A) reacting said compound of formula (I) with a mixture of hydrogen and carbon monoxide under hydroformylation conditions in the presence of a suitable hydroformylation catalyst, preferably based on rhodium(I) and a phosphine binding agent, and optionally a suitable solvent, to produce a compound of formula (II): HOC-H ２ -CHRR'-(Q)-COR'' (-) obtaining the corresponding ω-oxocarboxylic acid derivative of formula (II), wherein R′, R″ and Q have the corresponding meanings as specified above; (B) subjecting said compound of formula (II) obtained in step (A) to reductive amination by reaction with hydrogen and ammonia in the presence of a suitable catalyst, preferably in the absence of an intermediate purification step of the compound of formula (II) from other reaction products, to obtain an ω-aminocarboxylic acid derivative of formula (III), H ２ N-CH ２ -CH ２ -CHR’-(Q)-COR’’ (III) separating it from any reaction solvent; (C) optionally subjecting said compound of formula (III) to hydrolysis to obtain the corresponding ω-aminocarboxylic acid of formula (III), wherein R″ is OH; in order, A process for the preparation of an ω-aminocarboxylic acid of formula (III) or a derivative thereof.

2. 2. The process of claim 1, wherein the hydroformylation reaction in step (A) is carried out at a temperature of 60 to 140°C and a pressure of 1.5 to 6 MPa, preferably in a solvent selected from an ether, an alcohol, or an aromatic solvent.

3. 2. The process of claim 1, wherein the hydroformylation reaction in step (A) is carried out in the presence of a catalyst comprising a ligand consisting of at least one phosphine and a soluble salt or complex of a metal selected from rhodium, cobalt, iridium, ruthenium, preferably rhodium.

4. The catalyst is HRh(CO)(PPh ３ ) ３ , (acac)Rh(CO) ２ , [Rh(COD)Cl] ２ and a bidentate or polydentate phosphine.

5. 2. The process according to claim 1, wherein the reaction mixture obtained in step (A) is transferred to step (B) without carrying out any separation step except for possible evaporation of at least a portion of the solvent and recovery of the solvent using one of the methods known in the literature.

6. 2. The process according to claim 1, wherein the reductive amination step (B) is carried out with ammonia in the presence of hydrogen at a temperature of from 30 to 200°C, preferably from 50 to 150°C, and preferably at a pressure of from 3 to 15 MPa, more preferably from 6 to 9 MPa.

7. 10. The method of claim 1, wherein the reductive amination step (B) is carried out in the presence of a catalyst comprising cobalt or nickel.

8. In the step (B), ammonia and hydrogen are reacted to form a mixture of 5 to 25 NH ３ / H ２ The method of claim 1, wherein the molar ratio is

9. 2. The process according to claim 1, wherein in the compound of formula (III) obtained in step (B), R″ is an —OR group with R=C1-C5 alkyl, and said hydrolysis step (C) is carried out in an aqueous environment in the presence of an acidic or basic catalyst, preferably a basic catalyst, more preferably sodium hydroxide or potassium hydroxide.

10. 2. The method according to claim 1, wherein the ω-unsaturated carboxylic acid compound of formula (I) is an ester of 9-decenoic acid, preferably 9-DAME.

11. 10. The method of claim 1 for preparing 11-aminoundecanoic acid.

12. 12. A lubricating composition comprising a base oil and at least one additive, wherein said additive and / or said base oil is an ω-aminocarboxylic acid of formula (III) according to claim 1 or a derivative thereof of formula (III) according to claim 1, wherein said ω-aminocarboxylic acid of formula (III) and / or said derivative of formula (III) is preferably obtainable according to the method of any one of claims 1 to 11.

13. 13. The lubricating composition of claim 12, wherein the ω-aminocarboxylic acid of formula (III) or a derivative thereof is derived from an ω-unsaturated carboxylic acid compound of formula (I) of renewable origin, preferably starting from methyl 9-decenoate (9-DAME) obtained from the metathesis reaction of vegetable oils and fats from renewable resources.

14. 14. The biolubricant of claim 13, wherein the total formulation contains at least one percent (1%) of renewable carbon by weight and is derived from an ω-aminocarboxylic acid of formula (III) or a derivative thereof of formula (III).

15. 14. The biolubricant of claim 13, wherein the content of carbon from renewable raw materials is at least 25% by weight relative to the single component (base oil and / or viscosity modifier and / or additive) and is derived from an ω-aminocarboxylic acid of formula (III) or a derivative thereof of formula (III).

16. 16. The biolubricant of claim 15, wherein the content of carbon from renewable sources is at least 50%.

17. 12. A method for preparing a lubricating or biolubricating composition comprising preparing an ω-aminocarboxylic acid of formula (III) or a derivative thereof of formula (III) according to the method of any one of claims 1 to 11, and additionally comprising the additional step of subsequently incorporating said ω-aminocarboxylic acid, derivative thereof of formula (III), or a further derivative of one of the above, into a composition comprising at least one lubricating base stock (base oil).