Selective hydrogenation of polyunsaturates

Abstract

The present invention provides a process for the hydrogenation of polyunsaturated hydrocarbon compounds, in particular di-olefins and alkynes, more particularly di-olefins, said process comprising contacting a feed comprising one or more polyunsaturated hydrocarbon compounds with a catalyst comprising copper and carbon in the presence of hydrogen, preferably wherein the catalyst is a copper catalyst on a carbon-containing support. The present invention also provides a process for producing a copper catalyst on a carbon-containing support and the use of a copper catalyst on a carbon-containing support to increase the selectivity towards di-olefin hydrogenation over mono-olefin hydrogenation in a process for hydrogenation of one or more di-olefins.

Claims

1. A process for the hydrogenation of polyunsaturated hydrocarbon compounds, said process comprising contacting a feed comprising at least one di-olefin in the presence of hydrogen with a catalyst comprising copper on a carbon-containing support material, wherein the hydrogenation selectively hydrogenates the at least one di-olefin over a corresponding mono-olefin.

2. The process according to claim 1, wherein the carbon-containing support material is a carbon-based support material.

3. The process according to claim 2, wherein the carbon-based support material is selected from graphite, graphene, carbon aerogels, carbon nanotubes and carbon nanofibers and carbon nanoplatelets, polymeric materials, carbon black, turbostratic carbon and activated carbon.

4. The process according to claim 1, wherein the catalyst additionally comprises one or more metallic promoters or modifiers selected from silver, gold, potassium, sodium, zinc, manganese, chromium or mixtures thereof, either in their metallic form or in the form of oxides.

5. The process according to claim 1, wherein the catalyst comprises copper in an amount of from 1 to 15 wt. % based on the total weight of the catalyst.

6. The process according to claim 1, wherein the feed further comprises at least one mono-olefin.

7. The process according to claim 1, wherein the proportion of di-olefins in the feed relative to mono-olefins is less than 5% v/v.

8. The process according to claim 1, wherein the feed further comprises at least one alkyne.

9. The process according to claim 1, wherein the feed comprises butene, butadiene and optionally butyne.

10. The process according to claim 1, wherein the contacting step is performed at a temperature of at least 50° C. and less than 300° C.

11. The process according to claim 1, wherein the contacting step is performed at a pressure which is at or above atmospheric pressure.

12. The process according to claim 1, wherein the surface-averaged particle size of copper particles on the carbon-containing support material is in a range of from 0.5 to 20 nm.

Description

EXAMPLES

(1) In the examples described hereinafter, analysis was performed using the following methods.

(2) N.sub.2 Physisorption

(3) N.sub.2 physisorption isotherms were measured at −196° C. on a Micromeritics, TriStar 3000 V6.08 apparatus. Prior to the measurements, the samples were outgassed at 150° C., under dynamic vacuum for 14 h. The specific surface areas were calculated using multi-point Brunauer-Emmet-Teller (BET) analysis (0.05<P/P.sub.0<0.25). The total pore volume was calculated as single point pore volume at P/P.sub.0 of 0.99 and pore diameter distribution determined by Barrett-Joyner-Halenda (BJH) analysis applied to the adsorption branch.

(4) TPR-TCD

(5) Temperature programmed reduction (TPR) measurements on the final Cu/C catalysts were performed using a Micromeritics Autochem II ASAP 2920, equipped with a thermal conductivity detector (TCD). Prior to the measurements, the samples were dried at 120° C. for 0.5 h under Ar flow, before cooling down to room temperature. Next, the temperature was increased at 2° C. min.sup.−1 to 400° C., in 5% H.sub.2/Ar flow (1 mL min.sup.−1 mg.sub.cat.sup.−1). During this step, the H.sub.2 consumption was measured using the TCD and normalized to the amount of Cu in each sample.

(6) The degree of reduction was calculated from the H.sub.2 consumption by assuming the reduction stoichiometry: CO.sup.IIO+H.sub.2.fwdarw.Cu.sup.0+H.sub.2O. All catalyst could be completely reduced at 200° C.

(7) XRD

(8) Ex-situ x-ray diffraction was performed on a Bruker D8 powder X-ray diffractometer equipped with a Lynxeye detector. The used radiation was Co-Kα12 (λ=0.179026 nm), operated at 30 kV, 45 mA and a V20 variable slit. Diffractograms were taken first directly after the final reduction step in the synthesis. In the glovebox, a XRD specimen holder was loaded and subsequently sealed with an airtight transparent dome-like cap (A100B33, Bruker AXS), to collect diffractograms under Ar atmosphere. Diffractograms were typically collected at room temperature from 5-95 °2θ, with 0.1° increment and normalized to the intensity of the (002) diffraction of graphitic carbon at 30.9 °2θ. No background subtraction or smoothing was performed. Copper crystallite sizes were calculated using peak deconvolution software (Topas V5, Bruker AXS), applying the Scherrer equation with a shape factor k=0.1, to the Cu.sup.0 (111) diffraction at (50.7 °2θ) and the Cu.sup.0 (200) diffraction at (59.3 °2θ) (Patterson 1939).

(9) TEM and HAADF-STEM

(10) TEM imaging was performed on a Tecnai 20 (FEI) microscope and HAADF-STEM on a Talos F200X (FEI) microscope, both operated at 200 kV. To avoid electron beam induced particle growth, TEM images were acquired with a maximum electron dose-rate of ˜5 electrons per nm.sup.2 s.sup.−1. TEM samples were prepared by grinding the catalyst into a fine powder, which was deposited directly onto a holey carbon coated copper TEM grid (Agar 300 mesh Cu). The surface-averaged particle size (PS) was determined by TEM analysis by measuring the size of at least 250 individual particles on different areas of the sample. The PS was calculated using: PS=√((Σ.sub.1.sup.nD.sub.i.sup.2)/(Σ.sub.1.sup.n)), wherein D.sub.i is the diameter of the i.sup.th particle.

(11) Gas Chromatography (GC)

(12) The composition of the effluent gas mixture was analysed by on-line gas chromatography (GC). Data was acquired every 15 min using a flame ionization detector (Perichrom PR 2100, column filled with sebaconitrile 25% Chromosorb PAW 80/100 Mesh). GC peak areas were calibrated for butadiene, trans-2-butylene, cis-2-butylene, 1-butylene, n-butane, proyplene and propane using a pre-mixed calibration gas. The gas phase concentrations were calculated on the measured peak areas. To accurately quantify the hydrogenation of the mono-olefin propylene, the formation of propane was followed by GC. The butadiene reactant gas contained around 0.25% of cis-2-butylene trace impurity. The propylene reaction gas contained around 0.025% propane impurity. For these trace amounts, no significant influence on reaction kinetics is expected. For product analysis of these trace compounds, the initial concentration is subtracted from the measured value under reaction measurement. A blank measurement was performed to determine the fluctuations in butadiene flow and GC analysis. Herein, a standard deviation of ±1.1% butadiene was found. The GC detection limit was around 0.2 ppm for each analyte in the effluent gas, corresponding to <0.01% butane formation from butadiene.

Example 1—Oxidized Carbon Support

(13) The catalysts were prepared using both pristine and modified high surface area graphite (HSAG) as support. The carbon supports consist mostly of graphite sheets, with a pore size distribution ranging from 2-50 nm. Pristine HSAG (P-HSAG) with a surface area of around 500 m.sup.2 g.sup.−1 and 0.7 mL g.sup.−1 total pore volume was sourced from Timcal Ltd. The P-HSAG support was crushed and dried under dynamic vacuum at 170° C. for 1.5 h to remove absorbed water and finally stored in an Ar-filled glovebox until further use.

(14) Optionally, the pristine HSAG support was pre-treated by liquid phase HNO.sub.3 oxidation. 10 gram of HSAG was suspended in 400 mL of HNO.sub.3(aq) (68%), in a 1 L round bottom flask. The flask was equipped with a reflux cooler and heated using a heating mantle. The final temperature of 80° C. was reached after around 25 min and held then for 110 min. Subsequently, the reaction was quenched by diluting the suspension with cold deionized H.sub.2O to around 2 L. The oxidized carbon material was allowed to sediment during 30 min, before decanting the mother liquid. The carbon was washed with deionized H.sub.2O until reaching neutral pH, to remove residual HNO.sub.3. After the final decantation, the carbon was collected in a beaker and dried overnight at 120° C. The resulting oxidized HSAG (Ox-HSAG) support was crushed and dried under dynamic vacuum at 170° C. for 1.5 h to remove absorbed water and finally stored in an Ar-filled glovebox until further use. The BET surface area was 426±2 m.sup.2 g.sup.−1, with a total pore volume of 0.62 mL g.sup.−1.

Example 2—0.6 nm Cu/C Catalyst

(15) A copper catalyst supported on a carbon-containing support (from here on referred to as Cu/C) with 0.6 nm Cu clusters was prepared, with a Cu loading of 2.7 wt %. Herein, around 2 g of the dried Ox-HSAG support of Example 1 was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the Cu content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 230 and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and slowly exposed to air to obtain well-defined and high-dispersed Cu.sup.II species. 0.6 nm Cu.sup.0 clusters were prepared in-situ by reduction inside the catalytic reactor at 200° C. An ex-situ reduction was performed on a sample under the same conditions to allow for XRD and HAADF-STEM analysis of the actual catalyst used in catalytic testing.

(16) No copper crystallites could be observed by XRD under an argon atmosphere, after the ex-situ reduction treatment After passivation, no CuO or Cu.sub.2O crystallites were observed by XRD. HHAADF-STEM was employed to determine the particle size, which was found to be 0.6±0.3 nm. Results of the various analyses, including an analysis of the copper particle dispersion, are provided in Table 1 below.

Example 3—3 nm Cu/C Catalyst

(17) A Cu/C catalyst with 3 nm particle size was prepared with a Cu loading of 6.3 wt %. Herein, around 2 g of dried Ox-HSAG support of Example 1 was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 230° C. and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and treated with 20 vol % O.sub.2/N.sub.2 at room temperature to obtain well-defined and high-dispersed Cu.sup.II species. Then, the samples were flushed with N.sub.2 for 30 min. After flushing, the samples were reduced by heating to 150° C. under 5 vol % H.sub.2/N.sub.2 flow (˜1.5 mL min.sup.−1 mg.sub.cat.sup.−1). The heating ramp was 2° C. min.sup.−1, with 2 h hold at 150° C. Next, the temperature was increased at 2° C. min.sup.−1 to 250° C. with 1 h hold, under the same atmosphere. After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

(18) Cu.sup.0 crystallites of 2.0 nm were observed by XRD. TEM investigations showed 2.7±0.6 nm copper nanoparticles well-dispersed throughout the carbon. Results of the various analyses, including an analysis of the copper particle dispersion, are provided in Table 1 below.

Example 4—6 nm Cu/C Catalyst

(19) A Cu/C catalysts with 6 nm particle size was prepared with a Cu loading of 6.3 wt %. Herein, around 2 g of dried Ox-HSAG support of Example 1 was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 230° C. and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and treated with 20 vol % O.sub.2/N.sub.2 at room temperature to obtain well-defined and high-dispersed Cu.sup.II species. Then, the samples were flushed with N.sub.2 for 30 min. After flushing, the samples were reduced by heating to 150° C. under 5 vol % H.sub.2/N.sub.2 flow (˜1.5 mL min.sup.−1 mg.sub.cat.sup.−1). The heating ramp was 2° C. min.sup.−1, with 2 h hold at 150° C. Next, the temperature was increased at 2° C. min.sup.−1 to 400° C. with 1 h hold, under the same atmosphere. After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

(20) Cu.sup.0 crystallites of 6.0 nm were observed by XRD. TEM investigations showed 6.3±2.0 nm copper nanoparticles well-dispersed throughout the carbon. Results of the various analyses, including an analysis of the copper particle dispersion, are provided in Table 1 below.

Example 5—13 nm Cu/C Catalyst

(21) A Cu/C catalysts with 13 nm particle size was prepared with a Cu loading of 12.1 wt %. Herein, around 2 g of dried P-HSAG support of Example 1 was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 2.0° C. min.sup.−1 to 230° C. and 1 h hold at 230° C., under 20% H.sub.2/N.sub.2 flow (100 mL min.sup.−1 g.sup.−1). The sample was cooled down to room temperature and flushed with N.sub.2 (100 mL min.sup.−1 g.sup.−1). Next, the catalyst was heated at 1° C. min.sup.−1 to 200° C. with 3 h at this temperature, under 5% O.sub.2/N.sub.2 flow (100 mL min.sup.−1 g.sup.−1). At 200° C., the gas flow was exchanged for 15% O.sub.2/N.sub.2 flow (100 mL min.sup.−1 g.sup.−1) with 1 h hold, before cooling down to room temperature and collecting the final catalyst.

(22) Moreover, an ex-situ reduction was done to allow for XRD and TEM analysis of the actual catalyst used for catalytic testing. Herein, the 13 nm Cu/C catalysts was loaded in a plug-flow reactor and heated at 2.0° C. min.sup.−1 to 200° C. and 1 h hold at 200° C., under 20% H.sub.2/N.sub.2 flow (200 mL min.sup.−1 g.sup.−1). After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

(23) Cu.sup.0 crystallites of 10.9 nm were observed by XRD. TEM investigations showed 12.9±4.8 nm copper nanoparticles well-dispersed throughout the carbon. Results of the various analyses, including an analysis of the copper particle dispersion, are provided in Table 1 below.

Example 6—19 nm Cu/C Catalyst

(24) A Cu/C catalysts with 19 nm particle size was prepared with a Cu loading of 6.3 wt %. Herein, around 2 g of dried Ox-HSAG support of Example 1 was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 230° C. and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and treated with 20 vol % O.sub.2/N.sub.2 at room temperature to obtain well-defined and high-dispersed Cu.sup.II species. Then, the samples were flushed with N.sub.2 for 30 min. After flushing, the samples were reduced by heating to 150° C. under 5 vol % H.sub.2/N.sub.2 flow (˜1.5 mL min.sup.−1 mg.sub.cat.sup.−1). The heating ramp was 2° C. min.sup.−1, with 2 h hold at 150° C. Next, the temperature was increased at 2° C. min.sup.−1 to 400° C. with 1 h hold, under the same atmosphere. Subsequently, the gas flow was changed to N.sub.2 (100 mL min.sup.−1 g.sup.−1) and the temperature increased to 500° C. at 2° C. min.sup.−1, with 1 h hold at 500° C. After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

(25) Cu.sup.0 crystallites of 14.0 nm were observed by XRD. TEM investigations showed 19.4±6.9 nm copper nanoparticles well-dispersed throughout the carbon. Results of the various analyses, including an analysis of the copper particle dispersion, are provided in Table 1 below.

Comparative Example A

(26) A copper catalyst supported on a titania-containing support (from here on referred to as Cu/TiO.sub.2) with a Cu loading of 1.7 wt % was prepared. Herein, around 2 g of commercially available P25 TiO.sub.2 (ex. Degussa) was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 250° C. and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and treated with 20 vol % O.sub.2/N.sub.2 at room temperature to obtain well-defined and high-dispersed Cu.sup.II species. Then, the samples were flushed with N.sub.2 for 30 min. After flushing, the samples were reduced by heating to 150° C. under 5 vol % H.sub.2/N.sub.2 flow (˜1.5 mL min.sup.−1 mg.sub.cat.sup.−1). The heating ramp was 2° C. min.sup.−1, with 2 h hold at 150° C. Next, the temperature was increased at 2° C. min.sup.−1 to 250° C. with 1 h hold, under the same atmosphere. After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

Comparative Example B

(27) A Cu/TiO.sub.2 catalyst with a Cu loading of 1.7 wt % was prepared. Herein, around 2 g of commercially available P25 TiO.sub.2 (ex. Degussa) was impregnated to incipient wetness in a round-bottom flask, under slight vacuum. An aqueous solution of Cu(NO.sub.3).sub.2 in 0.1 M HNO.sub.3, at pH of ˜1 was used. The precursor solution was added by syringe. The Cu concentration was adjusted to obtain the desired Cu weight loading. The impregnate was stirred for 24 h to homogenize the metal content. Next, the impregnate was dried overnight at room temperature, while stirred under dynamic vacuum. The dried impregnate was transferred to a plug-flow reactor and heated at 0.5° C. min.sup.−1 to 250° C. and 1 h hold at 230° C. under N.sub.2 flow (100 mL min.sup.−1 g.sup.−1), to decompose the nitrate precursor. The sample was cooled down and treated with 20 vol % O.sub.2/N.sub.2 at room temperature to obtain well-defined and high-dispersed Cu.sup.II species. Then, the samples were flushed with N.sub.2 for 30 min. After flushing, the samples were reduced by heating to 150° C. under 5 vol % H.sub.2/N.sub.2 flow (˜1.5 mL min.sup.−1 mg.sub.cat.sup.−1). The heating ramp was 2° C. min.sup.−1, with 2 h hold at 150° C. Next, the temperature was increased at 2° C. min.sup.−1 to 400° C. with 1 h hold, under the same atmosphere. After cooling down, the reduced sample was transferred in a closed vessel, to an Ar-filled glovebox (Mbraun Labmaster dp; <1 ppm H.sub.2O; <1 ppm O.sub.2).

Comparative Example C

(28) A gold catalyst supported on a carbon-containing support (from here on referred to as Au/C) with a Au loading of 1 wt % was prepared. First, an oxidized carbon nanotube support was prepared by liquid phase oxidation treatment. Herein, around 2 grams of commercial carbon nanotubes (ex. Baytubes) was suspended in 400 mL of HNO.sub.3 (aq) (68%), in a 500 mL round bottom flask. The flask was equipped with a reflux cooler and heated using a heating mantle. The final temperature of 120° C. was held for 120 min. After cooling down, the oxidized carbon nanotube support was collected by filtration, washed thoroughly with deionized water and dried at 120° C. overnight.

(29) Next, a deposition method using colloidal polyvinylpyrrolidone (PVP)-stabilized Au nanoparticles was used to prepare the Au/C catalyst. Herein, a freshly prepared solution of NaBH.sub.4 in methanol was added to 5 mL of a solution containing PVP (molecular weight around 29,000) and HAuCl.sub.4.3H.sub.2O in methanol. The amounts of reagents were adjusted to obtain a molar ratio of NABH.sub.4:PVP.sub.monomer:Au precursor as 10:10:1. The resulting solution was stirred overnight to ensure complete decomposition of NaBH4. Next, colloidal nanoparticles were immobilized on the support by adding the colloid solution to the oxidized carbon nanotube support suspended in a small volume of methanol, under vigorous stirring. The amount of support material was adjusted to obtain 1 wt % metal loading. The solid was recovered by centrifugation and washed twice with methanol and diethyl ether, and subsequently dried at 60° C. overnight. PVP was removed from supported Au nanoparticles by washing the catalyst in an excess of Milli-Q water at room temperature overnight. The final catalyst was collected after drying.

(30) Au.sup.0 crystallites of 4.9 nm were observed by XRD. Results of the analyses are provided in Table 1 below.

Comparative Example D

(31) A Au/C catalyst with Au loading of 4 wt % was prepared. First, a solution of Au(en).sub.2Cl.sub.3 metal precursor was prepared. Herein, 0.449 mL of an aqueous solution of HAuCl.sub.4 (17 wt % Au) containing 0.125 g (0.635 mmol) of Au) was diluted to 2.5 mL in demineralized H.sub.2O in a glass beaker. To this solution, 0.15 mL (2.25 mmol) of pure ethylene diamine was added dropwise, while stirring at 400 RPM. The beaker was covered by parafilm and aluminium foil to avoid exposure to light. The system was left to react for 30 min while stirring at 400 RPM. Subsequently, 30 mL of absolute ethanol was added to the solution and a yellow/white precipitate formed. The suspension was left overnight to settle the solid. The following day, the liquid was decanted and the yellow gold precursor was left overnight to dry in the dark. The following day, the gold precursor was re-dissolved in demineralized H.sub.2O to a total volume of 2.5 mL and stored at 4° C. until further use.

(32) Next, the gold precursor solution (1.88 mL) was dissolved in demineralized H.sub.2O to a total volume of 40 mL. While stirring at 400 RPM, 0.45 mL of a 1 M NaOH solution was added. Subsequently, 2 grams of dried Ox-HSAG from Example 1 was dispersed in the solution while stirring at 700 RPM and left the suspension stirring for 2 hours. Next, the solid was collected by repeated centrifugation (10 min at 4000 RPM) and decanting of the liquid, for three times. The solid was dried overnight at 60° C. and then under vacuum at room temperature for 24 hours. The Au/C catalyst was heated in a fluidized bed reactor, at 5° C. min.sup.−1 to 400° C. for 2 hours under a flow of 20% O.sub.2/N.sub.2 (100 mL min.sup.−1 g.sup.−1). After cooling down, the final catalysts was collected and stored in the dark until further use.

(33) Au.sup.0 crystallites of 28.5 nm were observed by XRD. Results of the analyses are provided in Table 1 below.

(34) TABLE-US-00001 TABLE 1 Cu loading Au loading Crystallite size Particle size Example (wt %) (wt %) (nm) (nm) 2 2.7 — <1 0.6 ± 0.3 3 6.3 — 2.0 2.7 ± 0.7 4 6.3 — 6.0 6.3 ± 2.0 5 12.1 — 10.9 12.9 ± 4.8  6 6.3 — 14.0 19.4 ± 6.9  A 1.7 — n.d. n.d. B 1.7 — n.d. n.d. C — 1 28.5 n.d. D — 4 4.9 n.d.

Example 7—Granulate Formation

(35) The passivated Cu/C catalysts of Examples 2-6 and Comparative Examples A-D were pelleted, ground and sieved to obtain a granulate size of 90-212 μm.

(36) To corroborate that the reaction was not mass transfer limited, copper catalysts with different granulate size (38-90, 90-212 and 212-425 μm) were tested. No significant differences in the activity profiles for catalysts of different granulate size were observed, indicating that the reaction was not hindered by internal or external mass transfer limitations. A blank measurement was done, using only Ox-HSAG from Example 1, SiC and glass wool plugs. After the typical pre-treatment method, no butadiene or propylene consumption was observed up to 300° C.

Example 8—Catalyst Dilution, Reactor Loading and Reduction of the Catalyst

(37) Catalytic hydrogenation tests were performed in a quartz plug flow reactor (4 mm internal diameter) at atmospheric pressure.

(38) The catalyst samples from Examples 2-6 and Comparative Examples A-D were diluted with SiC (granulate size 212-425 um) as indicated in Table 2 below. The desired catalyst was then loaded directly into a fixed-bed quartz reactor, onto a glass frit. Small glass wool plugs were added before and after the catalyst bed, to ensure that the catalyst bed remained in place.

(39) In-situ reduction of the catalyst was performed by heating the sample at 2° C. min.sup.−1 to 200° C., with 120 min hold at 200° C. (50 mL min.sup.−1 pure H.sub.2) to obtain Cu.sup.0.

(40) TABLE-US-00002 TABLE 2 Catalyst Weight of Catalyst (mg) Weight of SiC (mg) Example 2 47.4 85 Example 3 20.0 155 Example 4 20.0 155 Example 5 10.6 190 Example 6 20.0 155 Comparative 73.60 100 Example A Comparative 73.60 100 Example B Comparative 50.0 210 Example C Comparative 20.0 200 Example D

Example 9—Catalyst Activity

(41) The conversion of butadiene and propylene in a 1% butadiene in propylene feed composition for the catalyst loaded and reduced as described in Example 8 were studied at a reaction temperature of 30° C. to 195° C. The gas hourly space velocity (GHSV) of the gas feed was around 90,000 h.sup.−1. The feed gas had a composition of butadiene/proyplene/H.sub.2/He=0.15/15/10/24.85 mL min.sup.−1 with a total flow of 50 mL min.sup.−1.

(42) The results for butadiene and propylene conversion at 120° C. and 150° C. are presented in Table 3 below.

(43) TABLE-US-00003 TABLE 3 Conversions (%) at 120° C. Conversions (%) at 150° C. Example Butadiene Propylene Butadiene Propylene 2 35.99 0.00 96.44 0.01 3 99.76 0.01 100.00 0.05 4 100.00 0.02 100.00 0.03 5 0.61 0.00 100.00 0.02 6 0.00 0.00 11.01 0.01 A 0.00 0.00 1.42 0.00 B 0.00 0.00 3.88 0.02 C 5.33 0.00 2.14 0.00 D 0.48 0.00 1.03 0.00

Example 10—Catalyst Activity—Temperature Ramping Experiments

(44) Reactant conversion for di-olefins and mono-olefins of the catalysts loaded and reduced as described in Example 8 were studied as a function of temperature over a continuous temperature ramping experiment. For continuous temperature ramping experiments, the catalysts were cooled down to 30° C. under H.sub.2 flow, directly after the in-situ reduction and the sample exposed to the pre-mixed reaction gas feed containing 1,3-butadiene/propylene/H.sub.2/He in a ratio of 0.15/15/10/24.85 mL min.sup.−1 at 1 bar. For the catalysts of Examples 2 to 6, the reactor was heated at 0.5° C. min.sup.−1 to 195° C., cooled down to 30° C. and again heated to 195° C. at the same rate and atmosphere, for the catalysts of Comparative Examples A to D, the maximum heating temperature was greater than 195° C. During the temperature ramping, data was acquired every 7.5° C. After the ramp, the catalyst was cooled down and passivated at room temperature by slowly exposing it to air.

(45) The results for Examples 2-6 and Comparative Examples A-D are provided in Tables 4-12. In Tables 4-7 presented below, the butadiene conversion remained at 100% as measured at temperatures greater than the highest indicated temperature in the respective table.

(46) TABLE-US-00004 TABLE 4 Catalyst from Example 2 Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 83 0.00 0.00 90 0.42 0.00 98 1.05 0.00 105 1.03 0.00 113 5.22 0.00 120 35.99 0.00 127 69.66 0.00 135 84.45 0.00 143 92.27 0.01 150 96.44 0.01 158 98.55 0.01 165 99.55 0.01 172 99.86 0.01 180 100.00 0.02

(47) TABLE-US-00005 TABLE 5 Catalyst from Example 3 Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 90 0.00 0.00 98 0.46 0.00 105 0.64 0.00 113 57.96 0.00 120 99.76 0.01 128 100.00 0.03

(48) TABLE-US-00006 TABLE 6 Catalyst from Example 4 Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 90 0.00 0.00 98 0.07 0.00 105 17.86 0.00 113 86.22 0.01 120 100.00 0.02

(49) TABLE-US-00007 TABLE 7 Catalyst from Example 5 Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 97 0.00 0.00 105 0.40 0.00 113 0.59 0.00 120 0.61 0.00 127 0.76 0.00 135 43.45 0.00 143 92.90 0.01 150 100.00 0.02

(50) TABLE-US-00008 TABLE 8 Catalyst from Example 6 Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 127 0.00 0.00 135 1.84 0.00 143 5.11 0.00 150 11.01 0.01 158 20.20 0.01 165 30.77 0.01 172 42.20 0.01 180 53.10 0.01 187 63.49 0.02 195 72.32 0.02

(51) TABLE-US-00009 TABLE 9 Catalyst from Comparative Example A Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 143 0.00 0.00 150 1.42 0.00 158 1.59 0.00 165 1.73 0.00 173 2.82 0.00 180 2.45 0.00 188 3.27 0.00 195 3.17 0.00 203 3.51 0.00 210 5.02 0.00 218 6.15 0.00 225 9.11 0.00 233 13.73 0.00 240 18.94 0.00 248 28.94 0.00 255 40.77 0.00 263 60.37 0.00 270 79.09 0.00 278 86.85 0.01 285 86.20 0.01

(52) TABLE-US-00010 TABLE 10 Catalyst from Comparative Example B Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 128 0.00 0.01 135 1.24 0.01 143 3.24 0.01 150 3.88 0.02 158 4.49 0.02 165 5.54 0.02 173 6.96 0.03 180 8.39 0.03 188 9.68 0.03 195 12.59 0.03 203 15.64 0.03 210 20.77 0.03 218 28.86 0.03 225 39.02 0.02 233 55.34 0.02 240 77.16 0.02 248 97.18 0.02 255 99.97 0.03 263 100.00 0.03

(53) TABLE-US-00011 TABLE 11 Catalyst from Comparative Example C Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 30 3.38 0.00 38 1.95 0.00 45 1.36 0.00 53 2.09 0.00 60 1.21 0.00 68 0.79 0.00 75 1.55 0.00 83 2.93 0.00 90 3.40 0.00 98 2.75 0.00 105 1.76 0.00 113 2.87 0.00 120 5.33 0.00 128 3.62 0.00 135 4.46 0.00 143 2.64 0.00 150 2.14 0.00 158 2.64 0.00 165 4.17 0.00 173 3.12 0.00 180 7.23 0.01 188 8.45 0.01 195 9.54 0.01 203 9.52 0.01 210 13.29 0.01 218 13.32 0.01 225 17.52 0.01 233 17.31 0.01 240 21.83 0.01 248 19.39 0.01 255 21.42 0.00 263 19.26 0.00 270 21.01 0.00 278 18.47 0.00 285 18.72 0.00 293 17.74 0.00 300 15.76 0.00

(54) TABLE-US-00012 TABLE 12 Catalyst from Comparative Example D Temperature (° C.) Butadiene conversion (%) Propylene conversion (%) 98 0.00 0.00 105 0.04 0.00 113 0.13 0.00 120 0.48 0.00 128 0.81 0.00 135 0.81 0.00 143 0.34 0.00 150 1.03 0.00 158 1.01 0.00 165 1.29 0.00 173 1.41 0.00 180 1.89 0.00 188 2.30 0.00 195 2.80 0.00 203 3.47 0.00 210 3.89 0.00 218 4.33 0.00 225 4.98 0.00 233 5.38 0.00 240 5.50 0.00 248 5.80 0.00 255 6.11 0.00 263 6.08 0.00 270 5.84 0.00 278 5.21 0.00 285 0.00 0.00 293 0.11 0.00 300 0.35 0.00

(55) As can clearly be seen from Tables 5 and 6, above 120° C. effectively all of the butadiene was completely removed by the catalysts of Example 3 and 4, whilst the conversion of propylene was remarkably low, only ˜0.01-0.02% propylene was hydrogenated, even though propylene was supplied in 100-fold excess of 1,3-butadiene.

Example 11—Stability Testing

(56) The catalysts of Examples 3 and 4 which were studied as a function of time over an isothermal experiment. For the isothermal experiment, the Cu/C catalyst from used in Example 3 and Example 4 were cooled down to 80° C. under H.sub.2 flow, after in-situ reduction. Then, the catalysts were exposed to the reaction feed gas containing 1,3-butadiene/propylene/H.sub.2/He in a ratio of 0.15/15/10/24.85 mL min.sup.−1. The catalysts were then heated at 2° C. min.sup.−1 to 110° C. at 1 bar. Upon reaching the final temperature of 110° C., the reaction time was determined as t.sub.0. The catalyst was held at 110° C. for at least 100 h on stream, before cooling down and passivating the sample at room temperature by slowly exposing it to air. The results are presented in Tables 13 and 14 below.

(57) TABLE-US-00013 TABLE 13 Catalyst from Example 3 Time on Butadiene Propylene Cu time yield stream conversion conversion (mmol.sub.butadiene s.sup.−1 (h) (%) (%) gram.sub.Cu.sup.−1) 0 90.80 0.01 82.29 10 53.47 0.00 48.46 20 49.22 0.00 44.60 30 46.37 0.00 42.03 40 47.00 0.00 42.59 50 47.07 0.00 42.66 60 48.98 0.00 44.39 70 46.95 0.00 42.55 80 48.18 0.00 43.66 90 48.22 0.00 43.70 100 48.01 0.00 43.51

(58) TABLE-US-00014 TABLE 14 Catalyst from Example 4 Time on Butadiene Propylene Cu time yield stream conversion conversion (mmol.sub.butadiene s.sup.−1 (h) (%) (%) gram.sub.Cu.sup.−1) 0 99.54 0.04 90.21 10 89.72 0.01 81.31 20 87.16 0.01 78.99 30 85.25 0.00 77.25 40 84.43 0.00 76.51 50 84.42 0.00 76.51 60 84.14 0.00 76.25 70 82.94 0.00 75.16 80 82.58 0.00 74.84 90 81.90 0.00 74.22 100 79.71 0.00 72.24

(59) During the first hours on stream, the catalysts showed higher conversion than in the temperature ramping experiments at 110° C. This activation is likely due to changes in catalyst structure, which were not apparent during the temperature ramping experiments. The conversions decrease most rapidly in the first 20 h on stream and then showed a significantly slower rate of decrease of conversion.

(60) A cause for change in activity for supported metal nanoparticles, as observed in the stability tests, could be particle growth. Therefore, the spent catalysts were analysed after 100 h on stream. The samples of catalyst from Example 3 grew to 4.7±2.1 nm, whereas the samples of catalyst from Example 4 grew only slightly, to 6.5±1.9 nm.