WO2020034062A1 - Process for the reductive amination of a carbonyl compound - Google Patents

Process for the reductive amination of a carbonyl compound Download PDF

Info

Publication number
WO2020034062A1
WO2020034062A1 PCT/CN2018/100210 CN2018100210W WO2020034062A1 WO 2020034062 A1 WO2020034062 A1 WO 2020034062A1 CN 2018100210 W CN2018100210 W CN 2018100210W WO 2020034062 A1 WO2020034062 A1 WO 2020034062A1
Authority
WO
WIPO (PCT)
Prior art keywords
carbonyl compound
reductive amination
process according
conducted
furfural
Prior art date
Application number
PCT/CN2018/100210
Other languages
French (fr)
Inventor
Shi JIANG
Marc Pera Titus
Francois Jerome
Karine VIGIER
Changru MA
Original Assignee
Rhodia Operations
Le Centre National De La Recherche Scientifique
Universite De Poitiers
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rhodia Operations, Le Centre National De La Recherche Scientifique, Universite De Poitiers filed Critical Rhodia Operations
Priority to PCT/CN2018/100210 priority Critical patent/WO2020034062A1/en
Publication of WO2020034062A1 publication Critical patent/WO2020034062A1/en

Links

Images

Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D307/00Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/34Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
    • C07D307/38Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
    • C07D307/52Radicals substituted by nitrogen atoms not forming part of a nitro radical
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D307/00Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/02Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
    • C07D307/04Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members
    • C07D307/10Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having no double bonds between ring members or between ring members and non-ring members with substituted hydrocarbon radicals attached to ring carbon atoms
    • C07D307/14Radicals substituted by nitrogen atoms not forming part of a nitro radical

Definitions

  • the invention relates to a process for the reductive amination of a carbonyl compound.
  • the invention furthermore relates to a process for the preparation of a furan-derived amine starting from furfural or a derivative thereof.
  • furanic compounds produced from carbohydrates (hexoses or pentoses) contained in lignocellulosic biomass are of prime interest, giving access to a rich variety of chemicals and fuels.
  • furfural is a versatile platform chemical for the production of fuel additives, solvents, polymers, surfactants, perfumes, and agrochemical ingredients.
  • the low selectivity of the chemical reactions due to partial cleavage and/or formation of larger oligomers, such as humines still hamper the industrial-scale production of high-added valuable chemicals from furanic molecules.
  • Ru-based catalysts for one-pot synthesis of primary amines from aldehydes and ammonia are described by B. Dong, et al., in Catalysts 2015, 5, 2258-2270.
  • Various supports for the Ru are tested, including, for example, Al 2 O 3 , CeO 2 and zeolites. Highest yields of the desired amine were obtained with Ru/Al 2 O 3 as catalyst.
  • the present inventors have found that the reductive amination of a carbonyl compound can be conducted in high yield and at high selectivity in the presence of Ru supported on carbon (C) .
  • the present invention therefore relates to a process for the reductive amination of a carbonyl compound, wherein the process is conducted in the presence of Ru/C as catalyst.
  • furan-derived amines can be prepared in good yield starting from furfural or a derivative thereof, in particular from furfural or a derivative thereof being derived from biomass, by first conducting an aldol condensation between the furfural or derivative thereof and a carbonyl compound and then conducting a reductive amination of the product obtained in the first step in the presence of a Ru/C catalyst.
  • One embodiment of the present invention relates to a process for the reductive amination of a carbonyl compound, wherein the process is conducted in the presence of Ru/C as catalyst.
  • Ru/C as catalyst in the reductive amination of a carbonyl compound, in particular a furan derivative, results in high yield of the desired amine, in particular the furan-derived amine with only little undesired byproducts, compared to other known catalysts used in reductive amination, like Ru/Al 2 O 3 suggested by B. Dong, et al., in Catalysts 2015, 5, 2258-2270. This effect will be further demonstrated by the examples and comparative examples below.
  • R is any suitable residue.
  • any suitable reductant known to a person skilled in the art may be used.
  • a preferred reductant is hydrogen (H 2 ) .
  • any carbonyl compound may be used, i.e. aldehydes and ketones.
  • the carbonyl compound is an ⁇ , ⁇ -unsaturated carbonyl compound, i.e. ⁇ , ⁇ -unsaturated aldehyde or ⁇ , ⁇ -unsaturated ketone.
  • furan derivatives are preferred because they can be obtained from biomass. Furthermore, it was found that if the carbonyl compound is a ⁇ , ⁇ -unsaturated carbonyl furan derivative, only the double bond in the ⁇ , ⁇ -unsaturated carbonyl but not the double bonds in the furan ring are hydrogenated.
  • the ⁇ , ⁇ -unsaturated carbonyl is an ⁇ , ⁇ -ethylenically unsaturated carbonyl as exemplified in above Scheme 2, preferably an ⁇ , ⁇ -ethylenically unsaturated carbonyl furan derivative as exemplified in above Scheme 3.
  • the carbonyl compound used in the process of the present invention has the chemical formula (I') :
  • R a and R b independently of each other are H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  • Preferred embodiments of hydrocarbon residues for R a and R b are the same as defined for R 1 below.
  • the carbonyl compound is a ⁇ , ⁇ -unsaturated carbonyl compound having the chemical formula (I” ) :
  • R a and R b are defined as above.
  • the furan derivative used as ⁇ , ⁇ -unsaturated carbonyl in a preferred embodiment of the process of the present invention can have the chemical formula (I) :
  • R 1 is H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups, and
  • R 2 , R 3 and R 4 independently of each other are H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  • R 1 and the substituents on the furan ring are not particularly limited because the reductive amination takes place at the carbonyl moiety and the double bonds. Therefore, the substituents on the furan ring and R 1 can be selected by the skilled person according to the desired end product.
  • R 1 can be a hydrocarbon residue comprising 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms.
  • the hydrocarbon residue may be interrupted by one or more heteroatoms which can for example be selected from N, O, S and P.
  • heteroatoms can for example be selected from N, O, S and P.
  • interrupted means that the heteroatom is situated between at least two carbon atoms.
  • the hydrocarbon residue may be substituted with one or more functional groups which may for example be selected from halogen, hydroxyl, carbonyl, carboxyl, ester, amine, amide, imide, cyanate, isocyanate, nitro, sulfonyl, thiocyanate, isothiocyanate, and phosphate.
  • Any functional group may be situated at any position of the hydrocarbon residue, and, in case of for example carbonyl or ester, may interrupt the hydrocarbon residue.
  • Suitable hydrocarbon residues are for example alkyl which may be linear or branched, alkenyl which may be linear or branched, alkinyl which may be linear or branched, cycloalkyl and aryl, in particular phenyl. Combinations of these groups are possible as well, such as for example combinations of linear and cyclic groups, such as alkylaryl, alkyl-cycloalkyl, arylalkyl and cycloakyl-aryl groups.
  • hydrocarbon residue comprises one or more carbon-carbon double or triple bond
  • Preferred groups for R 1 are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl.
  • R 1 is H or a C 1 to C 20 , preferably C 1 to C 12 alkyl group which may be linear or branched
  • R 5 is H or a C 1 to C 20 , preferably C 1 to C 12 alkyl group which may be linear or branched
  • R 3 and R 4 are both H.
  • R 5 and R 1 may be the same or different, preferably R 5 and R 1 are the same.
  • the reductive amination reaction in the process of the present invention may be conducted with ammonia, R 6 -NH 2 or R 6 -NH-R 7 , wherein R 6 and R 7 independently are a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  • This hydrocarbon residue may have the same preferred embodiments as described for R 1 above.
  • R 6 -NH-R 7 the substituents R 6 and R 7 together with the nitrogen atom to which they are attached may form a ring.
  • amines are preferred among the functional groups with which the hydrocarbon residues for R 6 and R 7 may be substituted.
  • R 6 and, if present, R 7 independently are a C 1 to C 12 alkyl group which may be linear or branched and which may be substituted with one or more, preferably one amine (s) .
  • Preferred amines used in the reductive amination of the carbonyl compound in the process of the present invention are ammonia, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, methyldiamine, ethyldiamine, propyldiamine, butyldiamine, pentyldiamine and hexyldiamine.
  • the amount of Ru/C catalyst used in the process of the invention is not particularly limited but it was found that a certain minimum amount is desirable for obtaining good yield and selectivity. Therefore, in a preferred embodiment, the Ru/C is used in an amount of at least 1 wt%, preferably at least 2 wt%, more preferably at least 3 wt%, even more preferably at least 4 wt%and most preferably at least 5 wt%, each based on the weight of the carbonyl compound.
  • the reductive amination in the process of the invention can be conducted under usual process parameters well known to a person skilled in the art. In view of yield and selectivity of the process it is, however, preferred to conduct the reductive amination at a temperature of at least 80°C, preferably in the range of 80°C to 120°C, more preferably in the range of 90°C to 110°C, such as about 100°C.
  • the reductive amination in the process of the present invention can be conducted using H 2 .
  • the pressure of H 2 during the reaction is not particularly limited and can be selected according to the requirements. It was, however, found that in view of selectivity and yield it is desirable that the H 2 is used at a pressure of at least 5 bar, preferably in the range of 5 bar to 30 bar, more preferably in the range of 10 bar to 20 bar, such as in the range of 12 bar to 18 bar.
  • the reaction time is also not particularly limited and can be selected by the skilled person according to the desired yield and purity of the desired furan-derived amine product.
  • the reaction can be conducted for at least 8 hours, preferably at least 10 hours, more preferably at least 12 hours, such as about 14 hours.
  • a further advantage of the use of Ru/C as catalyst in the reductive amination in the process of the present invention is that the catalyst can be reused in several consecutive reactions and/or recycled after the first use or after the first or one of the further reuses. Recycling can be conducted for example by washing with ethanol, drying under vacuum at 80°C and reducing at 180°C. Such recycled catalyst shows almost the same activity as fresh catalyst. Therefore, in the process of the invention, fresh catalyst, recycled catalyst or a mixture thereof can be employed.
  • the present invention relates to a process for the production of a furan-derived amine comprising the steps of
  • the aldol condensation is conducted with furfural or a derivative thereof.
  • Suitable derivatives are, for example, 5-hydroxymethyl furfural, 5-aminomethyl furfural and diformylfuran.
  • diformylfuran is preferred.
  • the ketone used in the aldol condensation is not particularly limited and can be selected by a person skilled in the art according to the desired furan-derived amine.
  • the ketone can have the chemical formula (II) :
  • R 8 is H or a hydrocarbon residue which maybe interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  • R 8 is selected such that in the aldol condensation a furan derivative of the above chemical formula (I) is obtained (i.e. R 8 is defined as R 1 above) .
  • R 1 is defined as R 1 above.
  • the aldol condensation can be conducted using usual process parameters well known to a person skilled in the art.
  • the aldol condensation can be conducted in the presence of a base catalyst, such as A26 in hydroxide form, available from Sigma-Aldrich.
  • the reaction can, for example be conducted at an elevated temperature of about 120°C for about 2 hours without the presence of any additional solvent.
  • steps 1 and 2 can be conducted as one-pot process.
  • the aldol condensation and the reductive amination can be conducted in one reactor without separating the ⁇ , ⁇ -unsaturated carbonyl obtained in the aldol condensation step. It is rather possible to charge the reactor with the furfural or a derivative thereof, the carbonyl compound, the amine, the catalysts and H 2 and then conduct both reaction steps, i.e. the aldol condensation and the reductive amination without separating any intermediate products. It was found that nevertheless the desired furan-derived amine can be obtained at high overall yield of about 70 %.
  • the furfural or derivative thereof used in the aldol condensation in step 1 of the above process is derived from biomass.
  • the process comprises the further step of deriving the furfural or the derivative thereof from biomass. This additional step is conducted prior to step 1 above.
  • Figure 1 shows the influence of a catalyst on the yields of the desired product (a) and the undesired byproduct (b and d) ,
  • Figure 2 shows the influence of H 2 pressure on the yields of the desired product (a) and the undesired byproduct (b) ,
  • Figure 3 shows the influence of NH 3 pressure on the yields of the desired product (a) and the undesired byproduct (b) ,
  • Figure 4 shows the yields of the desired product (a) and the undesired byproduct (b) depending on the use of fresh, reused and refreshed catalyst.
  • the experiment was performed in a 30-mL tubular glass reactor with a sealable arrangement on top.
  • the reaction was performed using 1 g of furfural, 10 g of MIBK and 0.2 g of Amberlyst-26 catalyst in the glass tube preheated in an oil bath at 120°C for 2 h with stirring speed of 600 rpm.
  • the product was analyzed and quantified using an Agilent 7890 GC equipped with a HP-5 capillary column with 5 wt%phenyl groups and using n-dodecane as an internal standard. 1 H and 13 C NMR and GCMS analysis were also carried out.
  • the experiments were carried out in a 20-mL stainless steel reactor equipped with a pressure gauge and a safety rupture disk.
  • the reactor was charged with 0.3 g of the aldol condensation product from experiment 1.1 above, 1 g of ethanol and 30 mg of the pre-reduced catalyst.
  • the reactor was sealed and flushed with N 2 three times.
  • NH 3 (5 bar) and H 2 (15 bar) were introduced to the reactor.
  • the reactor was placed on hot plate provided with magnetic stirring at 100°C for 14 h.
  • the reactor was cooled down to room temperature and the mixture was analyzed using an Agilent 7890 GC equipped with a HP-5 capillary column with 5wt%phenyl groups and using n-dodecane as an internal standard. 1 H and 13 C NMR, as well as GC-MS analyses, were further conducted.
  • Example 1.2 By repeating Example 1.2 the effect of the H 2 pressure on the reductive amination reaction was further explored on one of the best performing catalysts (5%Ru/C) . The results are shown in Figure 2.
  • the H 2 pressure exerts a positive effect on the yield to the target product a in detriment to byproduct b.
  • a H 2 pressure of 15 bar affords full conversion of the aldolization reactant and a yield of 96%to a after 14 h reaction at 100 °C using a molar ratio between the reactant 1 and NH 3 of 1/10.
  • Reaction conditions 5%Ru/C (30 mg) , ⁇ , ⁇ -unsaturated ketone (0.3 g) , EtOH (1 g) , NH 3 (0.3 g) , H 2 (15 bar) , 100°C, 6 h.
  • the aldolization and reductive amination reactions were conducted simultaneously in the same reactor (one-reactor tandem concept) .
  • two catalysts were introduced to the reactor: (1) Amberlyst-26 (65 mg) for catalyzing the aldol condensation reaction between furfural (162 mg) and MIBK (169 mg) in ethanol (1 g) , and (2) 5%Ru/C (30 mg) for catalyzing the reductive amination.
  • the reaction was kept constant at 100°C for the two reactions.
  • NH 3 (0.3 g) and H 2 (15 bar) were introduced after 4 h to ensure that enough aldolization product was formed.
  • the amine product a was generated with a yield of 70%.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Furan Compounds (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)

Abstract

The invention relates to a process for the reductive amination of a carbonyl compound. The invention furthermore relates to a process for the preparation of a furan-derived amine starting from furfural or a derivative thereof.

Description

Process for the reductive amination of a carbonyl compound
TECHNICAL FIELD OF THE INVENTION
The invention relates to a process for the reductive amination of a carbonyl compound. The invention furthermore relates to a process for the preparation of a furan-derived amine starting from furfural or a derivative thereof.
BACKGROUND
The depletion of fossil oil reserves has motivated intensive research on the development of chemical products from biomass. Biomass, mostly composed of carbohydrates, is a huge reservoir of renewable carbon with an annual production estimated at 180 billion metric tons. Hence, current research programs target the conversion of carbohydrates into value added chemicals.
Among biomass-derived reagents, furanic compounds produced from carbohydrates (hexoses or pentoses) contained in lignocellulosic biomass are of prime interest, giving access to a rich variety of chemicals and fuels. In particular, furfural is a versatile platform chemical for the production of fuel additives, solvents, polymers, surfactants, perfumes, and agrochemical ingredients. Despite the extensive literature dedicated to furanic compounds, the low selectivity of the chemical reactions due to partial cleavage and/or formation of larger oligomers, such as humines, still hamper the industrial-scale production of high-added valuable chemicals from furanic molecules.
Although the transformation of biomass into valuable nitrogen-containing compounds is highly desired, only few examples have been reported so far on furanic compounds. In particular, primary amines are widely used for the synthesis of polymers, dies, surfactants, pharmaceuticals and agrochemicals. Reductive amination of carbonyl compounds with ammonia (NH 3) and hydrogen (H 2) as a nitrogen source and reductant, respectively, has received much attention for the synthesis of primary amines as an alternative to synthetic processes with low atomic efficacy relying on toxic reagents and/or stoichiometric reductants.
Various heterogeneous catalysts have been developed for reductive amination reactions. Nonetheless, the synthesis of primary amines has been limited to the reductive amination of simple aryl and alkyl aldehydes, such as benzaldehyde, due to the formation of secondary and tertiary amines and/or undesired hydrogenation of carbonyl groups. In particular, the selective reductive  amination of carbonyl compounds containing reduction-sensitive functional groups, such as heterocycles and halogens, is often difficult.
US 3,565,954 suggests a process for preparing primary amines by reaction of carbonyl compounds with ammonia followed by hydrogenation of the imine produced. As carbonyl compound, furfural is employed and the reaction is conducted in the presence of a catalyst, such as Raney nickel deposited on a kieselgur carrier. The highest yield obtained in one of the examples of this document is 92 %.
The direct reductive amination of aldehydes and ketones using potassium formate as reductant and catalytic palladium acetate is described by B. Basu, et al., Synlett 2003, No. 4, 555-557. This document contains only one example for the reductive amination of an α, β-unsaturated carbonyl compound, which is, however, an aldehyde, namely cinnamaldehyde. The yield in this example is only 69 %and the aromatic phenyl ring is not hydrogenated.
Heterogeneous Ru-based catalysts for one-pot synthesis of primary amines from aldehydes and ammonia are described by B. Dong, et al., in Catalysts 2015, 5, 2258-2270. Various supports for the Ru are tested, including, for example, Al 2O 3, CeO 2 and zeolites. Highest yields of the desired amine were obtained with Ru/Al 2O 3 as catalyst.
Furthermore, the aldol condensation of furanic compounds has been studied aiming at the production of liquid alkanes. For example, J. Yang, et al., ChemSusChem, 2013, 6, 1149-1152 describes the production of C 10 and C 11 branched alkanes by the aldol condensation of furfural with methyl isobutyl ketone followed by a one-step hydrodeoxygenation under solvent free conditions.
Also M. Li et al., Green Chem. 2014, 16, 4371-4377 report the tandem aldol condensation-hydrogenation reaction of furfural with acetone over a Pd/CN@MgO biofunctional catalyst in a single reactor.
However, in aldol condensation reactions, the desired nitrogen-containing compounds are not obtained. Further reactions are rather required.
It is therefore desirable to provide a process for the reductive amination of a carbonyl compound, such as a furan derivative, which is highly selective towards the desired amine and which provides the desired amine in high yield. It is furthermore desirable to provide a process for the preparation of furan-derived amines based on biomass-derived furfural which can be conducted in a single reactor (one-reactor tandem concept) , i.e. a process wherein the aldol condensation and the hydrogenation amination are conducted as one-pot process.  Such process would afford the generation of furan-derived amines with molecular complexity and diversity without the need of separating the intermediates.
SUMMARY OF THE INVENTION
The present inventors have found that the reductive amination of a carbonyl compound can be conducted in high yield and at high selectivity in the presence of Ru supported on carbon (C) .
The present invention therefore relates to a process for the reductive amination of a carbonyl compound, wherein the process is conducted in the presence of Ru/C as catalyst.
The inventors furthermore found that furan-derived amines can be prepared in good yield starting from furfural or a derivative thereof, in particular from furfural or a derivative thereof being derived from biomass, by first conducting an aldol condensation between the furfural or derivative thereof and a carbonyl compound and then conducting a reductive amination of the product obtained in the first step in the presence of a Ru/C catalyst.
DETAILED DESCRIPTION
One embodiment of the present invention relates to a process for the reductive amination of a carbonyl compound, wherein the process is conducted in the presence of Ru/C as catalyst.
It was found that Ru/C as catalyst in the reductive amination of a carbonyl compound, in particular a furan derivative, results in high yield of the desired amine, in particular the furan-derived amine with only little undesired byproducts, compared to other known catalysts used in reductive amination, like Ru/Al 2O 3 suggested by B. Dong, et al., in Catalysts 2015, 5, 2258-2270. This effect will be further demonstrated by the examples and comparative examples below.
The reductive amination of a carbonyl compound in the presence of for example ammonia as amine is exemplified by the following general reaction scheme 1:
Scheme 1
Figure PCTCN2018100210-appb-000001
wherein R'and R”are any suitable residues.
In one embodiment of the invention wherein the carbonyl compound is an α, β-unsaturated carbonyl compound, the general reaction is as follows (scheme 2) :
Scheme 2
Figure PCTCN2018100210-appb-000002
wherein R'and R”are any suitable residues.
In this case, not only the carbonyl moiety is converted into an amine but additionally the carbon-carbon double bond is hydrogenated.
In another preferred embodiment of the invention wherein the α, β-unsaturated carbonyl compound is a furan derivative, the general reaction is as follows (scheme 3) :
Scheme 3
Figure PCTCN2018100210-appb-000003
wherein R” is any suitable residue.
In this case, only the α, β-carbon-carbon double bond is hydrogenated but not the double bonds of the furan ring.
In the reductive amination of the present invention any suitable reductant known to a person skilled in the art may be used. A preferred reductant is hydrogen (H 2) .
In the reductive amination of the present invention any carbonyl compound may be used, i.e. aldehydes and ketones.
In one embodiment the carbonyl compound is an α, β-unsaturated carbonyl compound, i.e. α, β-unsaturated aldehyde or α, β-unsaturated ketone.
In the context of the invention, furan derivatives are preferred because they can be obtained from biomass. Furthermore, it was found that if the carbonyl compound is a α, β-unsaturated carbonyl furan derivative, only the double bond in the α, β-unsaturated carbonyl but not the double bonds in the furan ring are hydrogenated.
In one embodiment the α, β-unsaturated carbonyl is an α, β-ethylenically unsaturated carbonyl as exemplified in above Scheme 2, preferably an α, β-ethylenically unsaturated carbonyl furan derivative as exemplified in above Scheme 3.
In one embodiment the carbonyl compound used in the process of the present invention has the chemical formula (I') :
Figure PCTCN2018100210-appb-000004
wherein R a and R b independently of each other are H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups. Preferred embodiments of hydrocarbon residues for R a and R b are the same as defined for R 1 below.
In a further embodiment of the present invention the carbonyl compound is a α, β-unsaturated carbonyl compound having the chemical formula (I” ) :
Figure PCTCN2018100210-appb-000005
wherein R a and R b are defined as above.
The furan derivative used as α, β-unsaturated carbonyl in a preferred embodiment of the process of the present invention can have the chemical formula (I) :
Figure PCTCN2018100210-appb-000006
wherein R 1 is H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups, and
R 2, R 3 and R 4 independently of each other are H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
R 1 and the substituents on the furan ring (R 2, R 3 and R 4) are not particularly limited because the reductive amination takes place at the carbonyl moiety and the double bonds. Therefore, the substituents on the furan ring and R 1 can be selected by the skilled person according to the desired end product. For example, R 1 can be a hydrocarbon residue comprising 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms.
The hydrocarbon residue may be interrupted by one or more heteroatoms which can for example be selected from N, O, S and P. In this context, "interrupted" means that the heteroatom is situated between at least two carbon atoms.
The hydrocarbon residue may be substituted with one or more functional groups which may for example be selected from halogen, hydroxyl, carbonyl, carboxyl, ester, amine, amide, imide, cyanate, isocyanate, nitro, sulfonyl, thiocyanate, isothiocyanate, and phosphate. Any functional group may be situated at any position of the hydrocarbon residue, and, in case of for example carbonyl or ester, may interrupt the hydrocarbon residue.
Suitable hydrocarbon residues are for example alkyl which may be linear or branched, alkenyl which may be linear or branched, alkinyl which may be linear or branched, cycloalkyl and aryl, in particular phenyl. Combinations of these groups are possible as well, such as for example combinations of linear and cyclic groups, such as alkylaryl, alkyl-cycloalkyl, arylalkyl and cycloakyl-aryl groups.
If the hydrocarbon residue comprises one or more carbon-carbon double or triple bond, it is possible that also such double or triple bond will be hydrogenated in the reductive amination reaction in the process of the invention.
Preferred groups for R 1 are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl.
The substituents on the furan ring, R 2, R 3 and R 4, may be H or hydrocarbon residues which preferably are defined as the hydrocarbon residue for R 1. In a certain embodiment, R 1 is H or a C 1 to C 20, preferably C 1 to C 12 alkyl group which may be linear or branched, R 2 is H or -CH=CH-CO-R 5, wherein R 5 is H or a C 1 to  C 20, preferably C 1 to C 12 alkyl group which may be linear or branched, and R 3 and R 4 are both H. In this embodiment, R 5 and R 1 may be the same or different, preferably R 5 and R 1 are the same.
The reductive amination reaction in the process of the present invention may be conducted with ammonia, R 6-NH 2 or R 6-NH-R 7, wherein R 6 and R 7 independently are a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups. This hydrocarbon residue may have the same preferred embodiments as described for R 1 above. Additionally, in case of R 6-NH-R 7, the substituents R 6 and R 7 together with the nitrogen atom to which they are attached may form a ring. Furthermore, among the functional groups with which the hydrocarbon residues for R 6 and R 7 may be substituted, amines are preferred.
In one embodiment, R 6 and, if present, R 7, independently are a C 1 to C 12 alkyl group which may be linear or branched and which may be substituted with one or more, preferably one amine (s) .
Preferred amines used in the reductive amination of the carbonyl compound in the process of the present invention are ammonia, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, methyldiamine, ethyldiamine, propyldiamine, butyldiamine, pentyldiamine and hexyldiamine.
The amount of Ru/C catalyst used in the process of the invention is not particularly limited but it was found that a certain minimum amount is desirable for obtaining good yield and selectivity. Therefore, in a preferred embodiment, the Ru/C is used in an amount of at least 1 wt%, preferably at least 2 wt%, more preferably at least 3 wt%, even more preferably at least 4 wt%and most preferably at least 5 wt%, each based on the weight of the carbonyl compound.
The reductive amination in the process of the invention can be conducted under usual process parameters well known to a person skilled in the art. In view of yield and selectivity of the process it is, however, preferred to conduct the reductive amination at a temperature of at least 80℃, preferably in the range of 80℃ to 120℃, more preferably in the range of 90℃ to 110℃, such as about 100℃.
The reductive amination in the process of the present invention can be conducted using H 2. The pressure of H 2 during the reaction is not particularly limited and can be selected according to the requirements. It was, however, found that in view of selectivity and yield it is desirable that the H 2 is used at a pressure  of at least 5 bar, preferably in the range of 5 bar to 30 bar, more preferably in the range of 10 bar to 20 bar, such as in the range of 12 bar to 18 bar.
The reaction time is also not particularly limited and can be selected by the skilled person according to the desired yield and purity of the desired furan-derived amine product. For example, the reaction can be conducted for at least 8 hours, preferably at least 10 hours, more preferably at least 12 hours, such as about 14 hours.
A further advantage of the use of Ru/C as catalyst in the reductive amination in the process of the present invention is that the catalyst can be reused in several consecutive reactions and/or recycled after the first use or after the first or one of the further reuses. Recycling can be conducted for example by washing with ethanol, drying under vacuum at 80℃ and reducing at 180℃. Such recycled catalyst shows almost the same activity as fresh catalyst. Therefore, in the process of the invention, fresh catalyst, recycled catalyst or a mixture thereof can be employed.
In a further embodiment, the present invention relates to a process for the production of a furan-derived amine comprising the steps of
1. conducting an aldol condensation between furfural or a derivative thereof and a carbonyl compound, and
2. conducting a reductive amination of the product received in step 1,
wherein the reductive amination is conducted as described with respect to the above embodiments of the invention including the preferred embodiments thereof.
This embodiment of the invention is exemplified by the following general reaction scheme 4:
Scheme 4
1. 
Figure PCTCN2018100210-appb-000007
2. 
Figure PCTCN2018100210-appb-000008
wherein R”is any suitable residue.
The aldol condensation is conducted with furfural or a derivative thereof. Suitable derivatives are, for example, 5-hydroxymethyl furfural, 5-aminomethyl furfural and diformylfuran. Among the furfural derivatives diformylfuran is preferred.
The ketone used in the aldol condensation is not particularly limited and can be selected by a person skilled in the art according to the desired furan-derived amine. For example, the ketone can have the chemical formula (II) :
Figure PCTCN2018100210-appb-000009
wherein R 8 is H or a hydrocarbon residue which maybe interrupted by one or more heteroatoms and which may be substituted with one or more functional groups. Preferably, R 8 is selected such that in the aldol condensation a furan derivative of the above chemical formula (I) is obtained (i.e. R 8 is defined as R 1 above) . Thus, also the above preferred embodiments for R 1 are applicable for R 8.
The aldol condensation can be conducted using usual process parameters well known to a person skilled in the art. For example, the aldol condensation can be conducted in the presence of a base catalyst, such as 
Figure PCTCN2018100210-appb-000010
 A26 in hydroxide form, available from Sigma-Aldrich. The reaction can, for example be conducted at an elevated temperature of about 120℃ for about 2 hours without the presence of any additional solvent.
It was furthermore found that in the process of the second embodiment of the present invention steps 1 and 2 can be conducted as one-pot process. Thus, the aldol condensation and the reductive amination can be conducted in one reactor without separating the α, β-unsaturated carbonyl obtained in the aldol condensation step. It is rather possible to charge the reactor with the furfural or a derivative thereof, the carbonyl compound, the amine, the catalysts and H 2 and then conduct both reaction steps, i.e. the aldol condensation and the reductive amination without separating any intermediate products. It was found that nevertheless the desired furan-derived amine can be obtained at high overall yield of about 70 %.
In a further embodiment of the present invention the furfural or derivative thereof used in the aldol condensation in step 1 of the above process is derived  from biomass. In this case, the process comprises the further step of deriving the furfural or the derivative thereof from biomass. This additional step is conducted prior to step 1 above.
The conversion of biomass to furfural can be conducted as described for example in WO 2014/008364, the content of which is incorporated herein by reference.
In the attached figures,
Figure 1 shows the influence of a catalyst on the yields of the desired product (a) and the undesired byproduct (b and d) ,
Figure 2 shows the influence of H 2 pressure on the yields of the desired product (a) and the undesired byproduct (b) ,
Figure 3 shows the influence of NH 3 pressure on the yields of the desired product (a) and the undesired byproduct (b) ,
Figure 4 shows the yields of the desired product (a) and the undesired byproduct (b) depending on the use of fresh, reused and refreshed catalyst.
The following examples are given by way of non-limiting illustration of the present invention.
EXAMPLES
Materials
5%Ru/C (49.90%moisture, Johnson Matthey) , 5%Ru/Al 2O 3 (Alfa Aesar) , 5%Ru/CeO 2, H-BEA (beta zeolite, Clariant) , Amberlyst-26 in hydroxide form (moisture 66-75%, Sigma-Aldrich) , furfural (99%, Sigma-Aldrich) , methyl isobutyl ketone (MIBK) (≥99%, Sigma-Aldrich) , ethanol (99.5%, J&K) , acetophenone (≥99%, Sigma-Aldrich) , 2-pentanone (≥99%, Sigma-Aldrich) , 2-heptanone (≥98%, Sigma-Aldrich) .
Example 1
1.1 Aldol Condensation
Figure PCTCN2018100210-appb-000011
The experiment was performed in a 30-mL tubular glass reactor with a sealable arrangement on top. The reaction was performed using 1 g of furfural, 10 g of MIBK and 0.2 g of Amberlyst-26 catalyst in the glass tube preheated in an oil bath at 120℃ for 2 h with stirring speed of 600 rpm. The product was analyzed  and quantified using an Agilent 7890 GC equipped with a HP-5 capillary column with 5 wt%phenyl groups and using n-dodecane as an internal standard.  1H and  13C NMR and GCMS analysis were also carried out.
1.2 Reductive Amination
The experiments were carried out in a 20-mL stainless steel reactor equipped with a pressure gauge and a safety rupture disk. In a given experiment, the reactor was charged with 0.3 g of the aldol condensation product from experiment 1.1 above, 1 g of ethanol and 30 mg of the pre-reduced catalyst. The reactor was sealed and flushed with N 2 three times. Then, NH 3 (5 bar) and H 2 (15 bar) were introduced to the reactor. The reactor was placed on hot plate provided with magnetic stirring at 100℃ for 14 h. After the reaction, the reactor was cooled down to room temperature and the mixture was analyzed using an Agilent 7890 GC equipped with a HP-5 capillary column with 5wt%phenyl groups and using n-dodecane as an internal standard.  1H and  13C NMR, as well as GC-MS analyses, were further conducted.
A series of catalysts based on supported Ru (5 wt%Ru/Al 2O 3, , 5 wt%Ru/CeCO 2, 5 wt%Ru/H-BEA, 5 wt%Ru/C; here wt%relates to Ru loading on the support) were tested to perform the reductive amination of the aldolization. The results are shown in Figure 1. Among the different catalysts, 5wt%Ru/C exhibits the best performance towards the primary amine (a) . Two additional byproducts are also observed: b with the α, β insaturation reduced, and the reduced byproduct d. Noteworthy, the imine intermediate c was not detected.
Figure PCTCN2018100210-appb-000012
Example 2
By repeating Example 1.2 the effect of the H 2 pressure on the reductive amination reaction was further explored on one of the best performing catalysts (5%Ru/C) . The results are shown in Figure 2. The H 2 pressure exerts a positive effect on the yield to the target product a in detriment to byproduct b. A H 2 pressure of 15 bar affords full conversion of the aldolization reactant and a yield of  96%to a after 14 h reaction at 100 ℃ using a molar ratio between the reactant 1 and NH 3 of 1/10.
Figure PCTCN2018100210-appb-000013
Example 3
By repeating Example 1.2 the effect of the NH 3 pressure on the reductive amination reaction over 5%Ru/C was further explored. The results are shown in Figure 3. The NH 3 pressure only exerts a moderate effect on the formation rate of the amine product a.
Figure PCTCN2018100210-appb-000014
Example 4
Analog to example 1.2 recyclability and reuse of 5%Ru/C was further studied. The results are shown in Figure 4. The catalyst show an excellent catalytic performance for 5 consecutive runs with neither loss of activity nor effect on the carbon balance. The yield to the product decreases slightly from 96%to 82%after the 4 th run. A further catalytic test on the refreshed catalyst after the 4 th run followed by washing with ethanol, drying under vacuum at 80℃ overnight and reducing at 180℃ for 1 h shows an activity almost unchanged.
Figure PCTCN2018100210-appb-000015
Example 5
The reduction amination over 5%Ru/C was further extended to other α, β-unsaturated ketones issued from the aldol condensation reaction of furfural with biobased ketones with variable chain length. In all cases a yield higher than 90%to the desired product is obtained.
Figure PCTCN2018100210-appb-000016
Reaction conditions: 5%Ru/C (30 mg) , α, β-unsaturated ketone (0.3 g) , EtOH (1 g) , NH 3 (0.3 g) , H 2 (15 bar) , 100℃, 6 h.
Example 6
In this example the aldolization and reductive amination reactions were conducted simultaneously in the same reactor (one-reactor tandem concept) . To this aim, two catalysts were introduced to the reactor: (1) Amberlyst-26 (65 mg) for catalyzing the aldol condensation reaction between furfural (162 mg) and MIBK (169 mg) in ethanol (1 g) , and (2) 5%Ru/C (30 mg) for catalyzing the reductive amination. The reaction was kept constant at 100℃ for the two reactions. NH 3 (0.3 g) and H 2 (15 bar) were introduced after 4 h to ensure that enough aldolization product was formed. The amine product a was generated with a yield of 70%.
Figure PCTCN2018100210-appb-000017

Claims (15)

  1. Process for the reductive amination of a carbonyl compound, wherein the process is conducted in the presence of Ru/C as catalyst.
  2. Process according to claim 1, wherein the reductive amination is conducted in the presence of H 2 as reductant.
  3. Process according to claim 1 or 2, wherein the carbonyl compound is an α,β-unsaturated carbonyl compound.
  4. Process according to any one of the preceding claims, wherein the carbonyl compound is a furan derivative.
  5. Process according to claim 4, wherein the furan derivative has the chemical formula (I) :
    Figure PCTCN2018100210-appb-100001
    wherein
    R 1 is H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups, and
    R 2, R 3 and R 4 independently of each other are H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  6. Process according to claim 5, wherein in the chemical formula (I) R 1 is H or C 1 to C 20 alkyl group which may be linear or branched, R 2 is H or -CH=CH-CO-R 5, wherein R 5 is H or a C 1 to C 20 alkyl group which may be linear or branched, and R 3 and R 4 are H.
  7. Process according to any one of the preceding claims wherein the carbonyl compound is reacted with ammonia, R 6-NH 2 or R 6-NH-R 7, wherein R 6 and R 7 independently are a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups and wherein R 6 and R 7 together with the nitrogen atom to which they are attached may form a ring.
  8. Process according to claim 7, wherein R 6 and R 7 are a C 1 to C 12 alkyl group which may be linear or branched and which may be substituted with one or more, preferably one amine (s) .
  9. Process according to any one of the preceding claims, wherein the Ru/C catalyst is used in an amount of at least 1 wt%, preferably at least 2 wt%, more preferably at least 3 wt%, even more preferably at least 4 wt%and most preferably at least 5 wt%, each based on the weight of the carbonyl compound.
  10. Process according to any one of the preceding claims, wherein the reductive amination is conducted at a temperature of at least 80℃, preferably in the range of 80℃ to 120℃, more preferably in the range of 90℃ to 110℃.
  11. Process according to any one of the preceding claims, wherein the reductive amination is conducted at a H 2 pressure of at least 5 bar, preferably in the range of 5 bar to 30 bar, more preferably in the range of 10 bar to 20 bar.
  12. Process for the preparation of a furan-derived amine comprising the steps of
    1. conducting an aldol condensation between furfural or a derivative thereof and a carbonyl compound, and
    2. conducting a reductive amination of the product obtained in step 1.according to the process of any one of claims 1 to 11.
  13. Process according to claim 12, wherein the carbonyl compound has the chemical formula (II) :
    Figure PCTCN2018100210-appb-100002
    wherein R 8 is H or a hydrocarbon residue which may be interrupted by one or more heteroatoms and which may be substituted with one or more functional groups.
  14. Process according to claim 12 or 13, wherein steps 1 and 2 are conducted as one-pot process.
  15. Process according to any one of claims 12 to 14, further comprising the step of deriving the furfural or the derivative thereof from biomass.
PCT/CN2018/100210 2018-08-13 2018-08-13 Process for the reductive amination of a carbonyl compound WO2020034062A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2018/100210 WO2020034062A1 (en) 2018-08-13 2018-08-13 Process for the reductive amination of a carbonyl compound

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2018/100210 WO2020034062A1 (en) 2018-08-13 2018-08-13 Process for the reductive amination of a carbonyl compound

Publications (1)

Publication Number Publication Date
WO2020034062A1 true WO2020034062A1 (en) 2020-02-20

Family

ID=69524626

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/100210 WO2020034062A1 (en) 2018-08-13 2018-08-13 Process for the reductive amination of a carbonyl compound

Country Status (1)

Country Link
WO (1) WO2020034062A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11827627B2 (en) 2021-06-04 2023-11-28 Vertex Pharmaceuticals Incorporated N-(hydroxyalkyl (hetero)aryl) tetrahydrofuran carboxamides as modulators of sodium channels
US11834441B2 (en) 2019-12-06 2023-12-05 Vertex Pharmaceuticals Incorporated Substituted tetrahydrofurans as modulators of sodium channels

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3565954A (en) * 1967-03-08 1971-02-23 Melle Bezons Process for preparing primary amines
SU1204617A1 (en) * 1984-01-09 1986-01-15 Научно-Исследовательский Институт Химии Саратовского Ордена Трудового Красного Знамени Государственного Университета Им.Н.Г.Чернышевского Method of producing derivatives of 3-(2-pyrrolidyl)-propanol-1

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3565954A (en) * 1967-03-08 1971-02-23 Melle Bezons Process for preparing primary amines
SU1204617A1 (en) * 1984-01-09 1986-01-15 Научно-Исследовательский Институт Химии Саратовского Ордена Трудового Красного Знамени Государственного Университета Им.Н.Г.Чернышевского Method of producing derivatives of 3-(2-pyrrolidyl)-propanol-1

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DAI YUNSHENG ET AL.: "Preparation of Ru/C Catalyst and Its Application in the Fine Chemical Industry", PRECIOUS METALS, vol. 33, no. 1, 29 February 2012 (2012-02-29), pages 84 - 88 *
DONG, BO ET AL.: "Heterogeneous Ru-Based Catalysts for One-Pot Synthesis of Primary Amines from Aldehydes and Ammonia", CATALYSTS, vol. 5, no. 4, 16 December 2015 (2015-12-16), pages 2258 - 2270, XP055687259 *
PONOMAREV, A. A. ET AL.: "Furan compounds. XVII. Synthesis of 1, 2-dihydrodipyrroles and pyrrolizidines by intramolecular catalytic dehydration of furan and tetrahydrofuran amines", ZHURNAL OBSHCHEI KHIMII, vol. 32, 31 December 1962 (1962-12-31), pages 97 - 101 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11834441B2 (en) 2019-12-06 2023-12-05 Vertex Pharmaceuticals Incorporated Substituted tetrahydrofurans as modulators of sodium channels
US11919887B2 (en) 2019-12-06 2024-03-05 Vertex Pharmaceuticals Incorporated Substituted tetrahydrofurans as modulators of sodium channels
US11827627B2 (en) 2021-06-04 2023-11-28 Vertex Pharmaceuticals Incorporated N-(hydroxyalkyl (hetero)aryl) tetrahydrofuran carboxamides as modulators of sodium channels

Similar Documents

Publication Publication Date Title
Manzer Catalytic synthesis of α-methylene-γ-valerolactone: a biomass-derived acrylic monomer
Zhao et al. Iron/amino acid catalyzed direct N‐alkylation of amines with alcohols
Andrushko et al. Amination of aliphatic alcohols and diols with an iridium pincer catalyst
Chia et al. Triacetic acid lactone as a potential biorenewable platform chemical
Liu et al. Switchable synthesis of furfurylamine and tetrahydrofurfurylamine from furfuryl alcohol over RANEY® nickel
US8598303B2 (en) Process to produce valerolactone from levulinic acid
Sordakis et al. Aqueous phase homogeneous formic acid disproportionation into methanol
JP5846126B2 (en) Method for producing aromatic alcohol or heterocyclic aromatic alcohol
CN106866331B (en) Method for preparing cyclopentadiene or dicyclopentadiene from furfuryl alcohol
Min et al. A dual-catalysis approach to the kinetic resolution of 1, 2-diaryl-1, 2-diaminoethanes
WO2020034062A1 (en) Process for the reductive amination of a carbonyl compound
Lenstra et al. Sustainable organophosphorus-catalysed Staudinger reduction
Liu et al. Copper-catalyzed synthesis of benzanilides from lignin model substrates 2-phenoxyacetophenones under an air atmosphere
Palomo et al. Catalytic Enantioselective Conjugate Addition of Nitromethane to α′‐Hydroxy Enones as Surrogates of α, β‐Unsaturated Carboxylic Acids and Aldehydes
WO2020034058A1 (en) PROCESS FOR REDUCTIVE AMINATION OF α,β-UNSATURATED CARBONYL COMPOUND
Shi et al. Gold (I)‐and Brønsted Acid‐Catalyzed Ring‐Opening of Unactivated Vinylcyclopropanes with Sulfonamides
Zonta et al. C3‐Symmetric Titanium (IV) Triphenolate Amino Complexes for a Fast and Effective Oxidation of Secondary Amines to Nitrones with Hydrogen Peroxide
CN102050741B (en) Process for producing nitroalcohols
CN106866345B (en) Method for preparing JP-10 aviation fuel from furfuryl alcohol
Ke et al. Alcohol promoted N-methylation of anilines with CO 2/H 2 over a cobalt catalyst under mild conditions
US20160152585A1 (en) Process for the production of furanic compounds comprising at least one amine function
CN108129426B (en) Method for synthesizing 2, 5-dimethylamino furan by catalytic hydrogenation of 2, 5-dicyanofuran
WO2020034057A1 (en) PROCESS FOR REDUCTIVE AMINATION OF α, β-UNSATURATED KETONE
AU2014334822A1 (en) Synthesis of diacids, dialdehydes, or diamines from THF-diols
CN109718850B (en) Method for preparing aviation kerosene precursor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18929929

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18929929

Country of ref document: EP

Kind code of ref document: A1