NEW CATALYTIC SYSTEM
The goal of the present invention was to find a new catalytic system with improved properties in selective hydrogenation of organic starting material.
Catalytic selective hydrogenations (= selective semihydrogenations) are important processes in the fine chemicals industry. The obtained products can be used as such (i.e. as flavor or fragrance compounds) or they can be used as intermediates for the production of other important compounds.
There are numerous catalytic systems (or catalysts) known for selective hydrogenations. Due to the importance of such selective catalytic hydrogenations, there is always a need to improve such catalytic systems or to find new catalytic systems for such selective catalytic hydrogenations.
Surprisingly, it has been found that a catalytic system comprising porous glass- particles, which are impregnated with Cu- and Pd- nanoparticles and which are coated with at least one ionic liquid, shows improved properties in selective catalytic hydrogenations.
The glass particles are doped with Cu-nanoparticles as well as with Pd-nanoparticles and the so doped (impregnated) glass particles are then coated with a layer of at least one ionic liquid.
Therefore the present invention relates to a catalytic system (I) comprising
porous glass particles, which are impregnated with Cu- and Pd- nanoparticles and which are coated with at least one ionic liquid.
The obtained selectivities and conversions are extremely good (
Glass is a well known composition. The glass used as carrier material for the embodiment of the present invention has a high amount of Si02.
The glass particles are used as carrier material for the catalytic system. The porous glass particles used in the catalytic system according to the present invention have a Si02 content of at least 90 weight-% (wt-%), based on the total weight of the glass particles.
The glass particles can have any shape and size. Preferably the porous glass particles, which are used as carriers are spheric and/or sphere-like.
Therefore the present invention relates to a catalytic system (II), which is catalytic system (I), wherein the glass particles are spheric and/or sphere-like.
Preferably the porous glass particles, which are used as carriers particles have an average particle diameter of 50 μΐη to 500 μΐη, more preferably 75 μΐη to 300 μΐη. In the context of the present invention term diameter means the longest dimension of the particles. The diameter can be measured by any commonly known method, such as microscope counting, Coulter counter or dynamic light scattering.
Therefore the present invention relates to a catalytic system (III), which is catalytic system (I) or (II), wherein the glass particles have an average particle diameter of 50 μΐη to 500 μΐη (preferably 75 μΐη to 300 μΐη).
Preferably the porous glass particles, which are used as carriers particles have an average pore size of 20 nm to 100 nm, more preferably 30 nm to 75 nm. The pore size is measured by using well known methods, such as BET. Therefore the present invention relates to a catalytic system (IV), which is catalytic system (I), (II) or (III), wherein the glass particles have an average pore size of 20 nm to 100nm (more preferably 30 nm to 75 nm).
Preferably the porous glass particles, which are used as carriers particles have a specific surface area of 50 m2g"1 to 300 m2g"\ preferably 60 m2g"1 to 200m2g"1. The specific surface area is measured by using well known methods, such as BET.
Therefore the present invention relates to a catalytic system (V), which is catalytic system (I), (II), (III) or (IV), wherein the glass particles have a specific surface area of 50 m2g"1 to 300 m2g"1 , preferably 60 m2g"1 to 200 m2g"1.
Preferably the porous glass particles, which are used as carriers particles have a pore volume of 1000 mm3g"1 to 2000 mm3g"\ more preferably 1200 mm3g"1 to 1600 mm3g"1. The pore volume is measured by using well known methods, such as BET.
Therefore the present invention relates to a catalytic system (VI), which is catalytic system (I), (II), (III), (IV) or (V), wherein the glass particles have a pore volume of 1000 mm3g"1 to 2000 mm3g"1 , preferably 1200 mm3g"1 to 1600 mm3g"1. Suitable glass particles are available commercially from various companies. TRISPOR®, TRISOPERL® and VITRADENT® are examples for suitable glass particles and they are produced and sold by Biosearch Technolgies Inc, VitraBio (Steinach, Germany).
As stated above, the porous glass particles are impregnated by Cu and Pd nanoparticles.
Preferably, the molar ratio of Cu-nanoparticles to Pd-nanoparticles (on the porous glass) is 10:1 to 1 :10, more preferably 1 :1 to 1 :8.
Therefore the present invention relates to a catalytic system (VII), which is catalytic system (I), (II), (III), (IV), (V) or (VI), wherein the ratio of Cu-nanoparticles to Pd-nanoparticles is 10:1 to 1 :10, preferably 1 :1 to 1 :8, more preferably 1 :1 to 1 :5.
Preferably the total metal nanoparticle loading (Cu and Pd) is 0.001 to 1 .0 mmolg"1 , more preferably 0.01 - 0.6 mmolg"1. The loading is determined by commonly known and used methods, such as ICP-OES (inductively coupled plasma optical emission spectrometry). Therefore the present invention relates to a catalytic system (VIII), which is catalytic system (I), (II), (III), (IV), (V), (VI) or (VII), wherein the metal nanoparticle loading is 0.001 - 1.0 mmolg"1 , preferably 0.01 - 0.6 mmolg"1.
Usually the Pd-nanoparticles have an average particle size of between 0.5 and 20 nm, preferably of between 2 and 15 nm.
Usually the Cu-nanoparticles are smaller than the Pd-nanoparticles.
Therefore the present invention relates to a catalytic system (VIM'), which is catalytic sys- tern (I), (II), (III), (IV), (V), (VI), (VII) or (VIII), wherein the Pd-nanoparticles have an average particle size of between 0.5 and 20 nm, preferably between of 2 and 15 nm..
The catalytic system according to the present invention is coated with a layer of one or more ionic liquid, such as 1 -ethyl-3-methylimidazolium acetate, 1 -ethyl-3- methylimidazolium dimethyl phosphate 1 -ethyl-3-methylimidazolium dicyanamide, 1 -ethyl- 3-methylimidazolium diethylphosphate, and 1 -ethyl-3-methylimidazolium trifluoroacetate.
Therefore the present invention relates to a catalytic system (IX), which is catalytic system (I), (II), (III), (IV), (V), (VI), (VII), (VIII) or (VIII'), wherein the at least one ionic liquid is cho- sen form the group consisting of ionic liquid 1 -ethyl-3-methylimidazolium acetate, 1 -ethyl- 3-methylimidazolium dimethyl phosphate, 1 -ethyl-3-methylimidazolium dicyanamide, 1 -
ethyl-3-methylimidazolium diethylphosphate, and 1 -ethyl-3-methylimidazolium trifluoro- acetate, preferred is 1 -ethyl-3-methylimidazolium acetate.
Preferably the catalytic system according to the present invention comprise the ionic liquid layer in an amount of 2 - 20 wt-%, based on the total weight of the catalytic system, preferably 5 - 1 5 wt-%.
Therefore the present invention relates to a catalytic system (X), which is catalytic system (I), (II), (III), (IV), (V), (VI), (VII), (VII I), (VIII') or (IX), wherein the amount of ionic liquid lay- er is 2 - 20 wt-%, preferably 5 - 15 wt-%, based on the total amount of the catalytic system.
The invention also relates to the process of production of catalytic systems (I), (I I), (III), (IV), (V), (VI), (VII), (VIII), (VI II'), (IX) and (X) as described above.
The catalytic systems are produced by impregnating the glass particles with the Cu and Pd nanoparticles (step a) and then coating it with a layer of at least one ionic liquid (step b). The impregnating (step a) of the porous glass particles with the Cu and Pd nanoparticles can be done by methods known to person skilled in the art.
Preferably the Cu and Pd-nanoparticles are applied (impregnated, doped) by wet- impregnation. In general the glass particles are put into a solvent (or a mixture of solvents). The Cu and the Pd are added afterwards in the form of a salt, which dissolves in the solvent (or solvent mixture). The solvent is then removed (usually by heating optionally by applying reduced pressure) and the impregnated glass particles are then calcined at elevated temperature.
It is possible to add the Cu and the Pd salts together to the glass particles (step a1) or to add the Cu salt first and then the Pd salt (step a2) or to add the Pd salt first and then the Cu salt (step aS).
Furthermore it is also possible to add the Cu salt first then calcine the so obtained glass particles at elevated temperature; suspend the so treated glass particles in a suitable solvent and add the Pd salt and calcine again at elevated temperature (step a'1).
Furthermore it is also possible to add the Pd salt first then calcine the so obtained glass particles at elevated temperature; suspend the so treated glass particles in a suitable solvent and add the Cu salt and calcine again at elevated temperature (step a'2).
Furthermore it also possible to carry out more than one impregnation step. This means that it is for example possible to apply Pd, then carry out the calcination step then apply Cu, then carry out the calcination step, then additionally apply Cu and/or Pd, carry out the application step.
Suitable solvents for the wet-impregnation step(s) are solvents which are inert and where- in the Pd salts and Cu salts are soluble, such as i.e. acetone.
Suitable Cu salts and Pd salts are Pd(ll)salts and Cu(ll) salts, such as i.e. Pd(ll)acetate (Pd(OAc)2), Pd(l l)acetylacetonate ((Pd(acac)), Pd(ll)chloride (PdCI2),
Cu(l l)acetylacetonate (Cu(acac)), Cu(l l)acetate (Cu(OAc)2), Cu(l l)chloride (CuCI2).
Step a'2 is preferred.
In the second step (step b) the particles of step a are coated by a ionic liquid or a mixture of ionic liquids. This is usually done by a wet impregnation. The particles obtained by any of the steps a is put in a solution of at least one ionic liquid in a suitable solvent (such as acetone) and afterwards the mixture is treated in a ultrasonic bath to degas the porous carrier and then the solvent is removed (for example by evaporation under reduced pressure at slightly elevated temperature).
The catalytic system according to the present invention is then obtained.
The catalytic systems (I), (II), (III), (IV), (V), (VI), (VI I), (VIII), (VII I'), (IX) and (X) are used in selective catalytic hydrogenations.
Usually the catalytic systems (I), (II), (I II), (IV) , (V), (VI), (VII), (VIII), (VIII'), (IX) and (X) are used for the hydrogenations of carbon-carbon triple bonds to carbon-carbon double bonds.
A preferred embodiment of the present invention is the use of a catalytic systems (I), (I I), (III), (IV), (V), (VI), (VI I), (VIII), (VI II'), (IX) and/or (X) in the selective hydrogenation of a compound of formula (A)
OH
HC≡C C R2 (A)
Ri
wherein Pn is a linear or branched C1 -C35 alkyl or linear or branched C5-C35 alkenyl moiety, wherein the C-chains can be substituted, and
R2 is a linear or branched C1 -C4 alkyl, wherein the C-chain can be substituted.
Preferred compounds of formula (A) are the following compounds of formula (Aa) - (Ac)
, and
Furthermore also aromatic compounds having carbon carbon triple bonds can be hydro- genated selectively by using a catalytic systems (I), (II), (III), (IV), (V), (VI), (VII), (VIII), (VIII'), (IX) and/or (X).
Such compounds are of formula (B)
wherein R is H or C6H5.
The hydrogenation can be carried out with or without solvents.
When a solvent (or a mixture of solvents) is used then the solvent has to be inert, which means that the solvent is not hydrogenated. Suitable (and preferred) solvents are hydro- carbons, such as hexane, cyclohexane, methylcyclohexane, heptane, toluene and xylene.
The hydrogenation can be carried out at a broad range of temperature and pressure.
The selective catalytic hydrogenation in accordance with the present invention can be car- ried out under conditions conventionally used for hydrogenations. Suitably, the selective catalytic hydrogenation is carried out at a pressure of about 0.1 to about 6 MPa and at a temperature of about 0°C to about 200°C. The selective catalytic hydrogenation can be carried out batch wise or in continuous mode.
Preferably, the pressure used for the selective catalytic hydrogenation is between 0.1 and 3 MPa, more preferably between 0.1 and 1.5 MPa, even more preferably between 0.15 and 1 MPa and most preferably between 0.2 and 0.8 MPa. Preferably, the reaction temperature for the selective catalytic hydrogenation is between 0°C and 150°C, more preferably between 20°C and 120°C, even more preferably between 40°C and 90°.
The compounds obtained by the hydrogenation process according to the present inven- tion can be used as such (for example as flavor or fragrance compounds) or can be used as an intermediate for further reactions.
The following Examples illustrate the invention further without limiting it. All percentages and parts, which are given, are related to the weight and the temperatures are given in °C, when not otherwise stated.
Catalyst preparation
Example 1 :
Materials:
porous glass beads TRISOPERL: Charge PG L 13/05 (VitraBio GmbH, Steinach, Germany); particle diameter: 100-200 μιη, pore size: 48.4 nm, pore volume: 141 0 mm3 g"1 , surface area: 1 23.9 m2 g"1.
Pd(OAc)2: purity = 98%
Cu(acac)2: purity = 99,99+%
Acetone: purity = technical
1 -ethyl-3-methylimidazolium acetate: purity =≥ 96%
Step 1 (= step a): Applying Pd via wet-impregnation
5 g of porous glass beads TRISOPERL were given to a solution of 0.45 mmol Pd(OAc)2 (103.09 mg) in 250 ml acetone. The mixture was treated 10 min in an ultrasound bath to degas the porous support. The solvent was evaporated at 500 mbar, 40 °C, and 90 rpm. Finally, the catalyst was calcined at 300 °C for 2 h.
Step 2 (= step a): Pd Cu/TP via wet impregnation:
5 g of Pd/TP of step 1 were given to a solution of 0.1 1 5 mmol Cu(acac)2 (29.45 mg) in 250 ml acetone. The mixture was treated 10 min in an ultrasound bath to degas the porous support. The solvent was evaporated at 500 mbar, 40 °C, and 90 rpm. Finally, the catalyst was calcined at 300 °C for 2 h. Step 3 (= step b) Cu/Pd TP + 10 wt% 1 -ethyl-3-methylimidazolium acetate via wet impregnation:
5 g of Cu/Pd4/TP of step 2 were given to a solution of 555.56 mg 1 -ethyl-3- methylimidazolium acetate in 250 ml acetone. The mixture was treated 10 min in an ultrasound bath to degas the porous support. The solvent was evaporated at 500 mbar, 40°C.
Table 1 : Features of the catalyst:
The following catalytic system were prepared as well in analogy to Example 1 . The Cu and the Pd amount was varied. All the other reaction conditions and amounts have not been amended. So the ionic liquid is 1 -ethyl-3-methylimidazolium acetate - loading and its concentration is 10 wt-%.
Table 2: further catalysts (cat 2
Other catalyst with a different Cu/Pd ratio were also produced. The reaction conditions were the same but only the amounts of Cu and Pd salts were adjusted to obain the ratio.
Hydroqenation process
Examples 10 - 17: Hydrogenation of Methylbutynol to Methylbutenol A solution of 50 g methylbutynol in 200 g heptane and "l OOmg of the catalyst (s. following table 3) was added to a 500ml autoclave. The reaction mixture was purged 3 times with nitrogen (pressurise to 6 bar absolute and release). Then the mixture was heated to 60 °C and purged 3 times with hydrogen (pressurise to 6 bar absolute and release). The mixture was pressurised to 3 bar hydrogen (absolut) and stirred at 2000 rpm. When the desired amount of hydrogen had been consumed, samples were taken and the reaction mixture was cooled to room temperature.
Table 3: Examples 12 - 15
Examples 18 - 25 : Hydrogenation of dehydrolinalool to linalool
A solution of 50 g dehydrolinalool in 200 g heptane and 10Omg of the catalyst (s. following table 4) was added to a 500ml autoclave. The reaction mixture was purged 3 times with nitrogen (pressurise to 6 bar absolute and release). Then the mixture was heated to 55 °C and purged 3 times with hydrogen (pressurise to 6 bar absolute and release). The mixture was pressurised to 3 bar hydrogen (absolute) and stirred at 2000 rpm. When the desired amount of hydrogen had been consumed, samples were taken and the reaction mixture was cooled to room temperature.
Table 4: Examples 18
Examples 26 - 34: Hydrogenation of dehydroisophytol to isophytol
A solution of 50 g dehydroisophytol in 200 g heptane and 100mg of the catalyst (s. following table 5) was added to a 500ml autoclave. The reaction mixture was purged 3 times with nitrogen (pressurise to 6 bar absolute and release). Then the mixture was heated to 85 °C and purged 3 times with hydrogen (pressurise to 6 bar absolute and release). The mixture was pressurised to 3 bar hydrogen (absolute) and stirred at 2000 rpm. When the desired amount of hydrogen had been consumed, samples were taken and the reaction mixture was cooled to room temperature.
Table 5: Examples 26
Catalyst preparation - alternative ionic liquids
The catalyst preparation method of example 1 was repeated with the same amounts, except that the ionic liquid used was changed.
Table 6: further catalysts (cat 35 - cat 36)
Hydroqenation process
Examples 37-39: Hydrogenation of phenylacetylene to styrene
A solution of 0.76 g phenylacetylene in 30 ml heptane and 50mg of the catalyst was added to an autoclave. The reaction mixture was purged 3 times with nitrogen. Then the mixture was heated to 50 °C and purged 3 times with hydrogen. The mixture was pressurised to 3 bar hydrogen (absolute) and stirred. At the indicated time point, samples were taken for GC analysis.
Table 7: Examples 37- 39
Examples 40-42: Hydrogenation of diphenylacetylene to stilbene
A solution of 1 .2 g diphenylacetylene in 30 ml heptane and 50mg of the catalyst was added to an autoclave. The reaction mixture was purged 3 times with nitrogen. Then the mixture was heated to 50 °C and purged 3 times with hydrogen. The mixture was pressurised
to 3 bar hydrogen (absolute) and stirred. At the indicated time point, samples were taken for GC analysis.
Table 8: Examples 40
As it can be seen from the Examples, the selective hydrogenations using the new catalytic systems do all have excellent selectivities and conversions.