Field of Invention

The current invention relates to the conversion of sustainable oil into fuel by using a catalyst and low pressure green hydrogen.

Background

The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

The global aviation industry, led by International Civil Aviation Organisation (ICAO) has pledged to reduce carbon emission by the aviation industry and adopted Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) scheme. The scheme complements several measures that need to be taken to reduce net carbon emission to a baseline level (2020 CO2 level), including the implementation of sustainable aviation fuel (SAF). In order to meet CORSIA, PETRONAS intends to develop a chemical process to produce sustainable aviation fuel (SAF), based on the abundantly available Malaysian feedstock, such as palm oil, biomass and natural rubber. The formulated fuel containing biocomponent must meet commercial jet fuel grade specification (i.e. Jet A and Jet A-1).

Natural rubber thermal cracking yields mixtures of cyclic and unsaturated hydrocarbons (limonene and isoprene). Palm oil can be catalytically hydrogenated to fuels, which is an existing technology known as HEFA-SPK which hydroprocesses esters and fatty acids to synthetic paraffinic kerosene. Nevertheless, HEFA-SPK consumes hydrogen (H2) intensively and the SAF produced from this process can only be blended into existing petroleum-based aviation fuel up to 50 vol.% only. In addition, the majority of H ₂ being used for HEFA-SPK is brown H ₂ coming from fossil-fuel, which could impact the life cycle analysis emission of this pathway.

Commercial HEFA-SPK technology utilizes high pressure molecular hydrogen, typically 40- 110 bar, to remove oxygenates from sustainable oil in a reaction process called hydrodeoxygenation (HDO). Since the green hydrogen produced from limonene dehydrogenation is less than 1 bar, one would need to compensate this low partial hydrogen pressure with a high activity catalyst in order to have a complete HDO reaction.

Typical existing methods used to synthesize commercial HDO catalyst include incipient wet impregnation (IWI) method where active metals like molybdenum Mo and tungsten W are deposited on supports like alumina or zeolites. This method inherently limits the amount of active metals because there are no chemical reactions happening between the active metal precursors and the support during the IWI method. While such catalyst is sufficient for HDO processes aided by high pressure of hydrogen, the HDO activity drops significantly when limonene is used as the only source of hydrogen.

Therefore, there exists a need to discover new materials and methods for converting oil from renewable feedstock into jet fuel.

Summary of Invention

It has been surprisingly found that the problems identified above can be solved using a synergistic process based on two natural resources: palm oil and rubber, which could produce entirely sustainable aviation fuel, without added external hydrogen supply. This may be achieved through the use of the metal sulphide catalyst and/or the methods described hereinbelow.

Aspects and embodiments of the current invention are provided by the following numbered clauses.

1 . A poorly crystalline metal sulfide catalyst, wherein the catalyst comprises:

Mo and/or W in a total amount of from 25 to 35 wt%;

Ni and/or Co in a total amount of from 0 to 25 wt%

S in an amount of from 20 to 28 wt.wt. %;

N or P in an amount of from 0 to 5 wt%; and

C in an amount of from 10 to 54 wt.wt. %, wherein: the Mo and W are, when present, in the form of MoS2and/or M0S3 , WS2 and/or WS3, or Mo«Wi -aS _y particles, where a is from 0.99 to 0.01 and y is 2 and/or 3; and the crystallinity of the catalyst is less than 80% as measured by powder x-ray crystallography

2. The catalyst according to Clause 1 , wherein the BET surface area of the catalyst is from 75 to 100 m ² /g. 3. The catalyst according to Clause 1 or Clause 2, wherein the catalyst comprises: Mo and/or W in a total amount of from 25 to 35 wt%;

Ni and/or Co in a total amount of from 0 to 25 wt%

S in an amount of from 20 to 28 wt.%;

N or P in an amount of from 0 to 5 wt%; and

C in an amount of from 32 to 54 wt.%; or

Mo and/or W in a total amount of from 27 to 30 wt%;

Ni and/or Co a total amount of from 0 to 20 wt%;

S in an amount of from 22 to 24 wt%;

N or P in an amount of from 3 to 4 wt%; and C in an amount of from 42 to 48 wt%.

4. The catalyst according to any one of the preceding clauses, wherein the catalyst comprises:

Mo in a total amount of from 25 to 35 wt%;

S in an amount of from 20 to 28 wt%;

N or P in an amount of from 1 to 5 wt%; and

C in an amount of from 32 to 54 wt.%.

5. The catalyst according to Clause 4, wherein the catalyst comprises:

Mo in an amount of from 27 to 30 wt%, such as about 28.9 wt%;

S in an amount of from 22 to 24 wt%, such as about 23.2 wt%;

N or P in an amount of from 3 to 4 wt%, such as about 3.5 wt%; and

C in an amount of from 42 to 48 wt%, such as about 44.4 wt%.

6. The catalyst according to Clause 4 or Clause 5, wherein the X-ray powder diffraction pattern displays broad peaks having a 20 value of about 33° and about 59°.

7. The catalyst according to any one of Claims 4 to 6, wherein the BET surface area is about 83.6 m ² /g.

8. The catalyst according to any one of the preceding claims, wherein:

(a) the crystallinity of the catalyst is less than 70%, such as less than 60%, such as less than 50%; and/or (b) the catalyst is attached to a solid support, optionally wherein the solid support is silica or a ceramic (e.g. Y-zeolite).

9. A method of forming a catalyst as described in any one of Clauses 1 to 8, the method comprising the steps of:

(a) providing a sulfur-containing metal organic compound or thiometallate salt; and

(b) subjecting the sulfur-containing metal organic compound or thiometallate salt to calcination at a temperature of from 300 to 400 °C under an inert gas flow for a period of time to provide the catalyst.

10. The method according to Clause 9, wherein the temperature is raised at a rate of from 3 to 4 °C per minute, such as about 3.5 °C per minute, until a target temperature is reached.

11 . The method according to Clause 9 or Clause 10, wherein:

(i) the temperature is about 350 °C; and/or

(ii) the sulfur-containing metal organic compound or thiometallate salt is homogenously mixed with a solid support prior to step (b) in Clause 9, optionally wherein the solid support is silica or a ceramic (e.g. Y-zeolite).

12. The method according to any one of Clauses 9 to 11 , wherein the period of time after the temperature of from 300 to 400 °C is reached is from 2 to 3 hours, such as about 2.5 hours.

13. The method according to any one of Clauses 9 to 12, wherein the inert gas is nitrogen.

14. A method of generating a deoxygenated organic material, the method comprising:

(a) providing a feedstock material comprising oxygen and a catalytic material suitable for converting the feedstock material comprising oxygen to a deoxygenated organic material; and

(b) contacting the feedstock material comprising oxygen with the catalytic material in a reaction vessel having a gas pressure of less than or equal to 2,000 kPa (20 bar) at a temperature of from 275 to 400 °C, such as from 300 to 380 °C, for a period of time to provide the deoxygenated organic material, wherein: the feedstock comprising oxygen is selected from one or more of the group consisting of triglycerides, fatty acids, and fatty acid esters; the gas pressure is provided solely by hydrogen gas or by hydrogen gas and an inert gas, where the hydrogen gas is provided by an external source of hydrogen gas and/or internally by the liberation of hydrogen gas from the hydrogen gas donor; and the catalytic material suitable for converting the feedstock material comprising oxygen to a deoxygenated organic material is selected from one or more of the group consisting of: a catalyst as described in any one of Clauses 1 to 8 and a commercially available CoMo catalyst (e.g. a catalyst as described in any one of Clauses 1 to 8).

15. The method according to Clause 14, wherein the pressure is about 1 ,000 kPa.

16. The method according to Clause 14 or Clause 15, wherein the gas pressure is provided by hydrogen gas and nitrogen, and the hydrogen gas is provided internally by the liberation of hydrogen gas from the hydrogen gas donor.

17. The method according to any one of Clauses 14 to 16, wherein the hydrogen gas donor is limonene.

18. The method according to any one of Clauses 14 to 17, wherein weight ratio of the catalytic material to the feedstock comprising oxygen is from 1 :15 to 1 :50, such as about 1 :19.

19. The method according to any one of Clauses 14 to 18, wherein, when a hydrogen gas donor is present, weight ratio of the feedstock comprising oxygen to the hydrogen gas donor is from 1 :5 to 1 :50, such as about 1 :9.

20. The method according to any one of Clauses 14 to 29, wherein the feedstock is selected from one or more of a palm oil (e.g. a refined palm oil), an algae oil (e.g. crude algae oil), canola/rapeseed oil, soybean oil, corn oil, sunflower oil, tallow, olive oil (e.g. virgin or used), peanut oil, castor oil and animal fats.

21 . The method according to any one of Clauses 14 to 29, wherein the sulfur-containing metal organic compound or thiometallate salts is an ionic liquid having a formula I:

[RlR2R3R4X]2[Bx'(A _x S _y O _z )a] I where:

A is selected from one or more of Mo and W;

B is, when present, Co and/or Ni; x is 1 to 3; x' is 0 or 1 ; y is 1 to 13; z is 0 to 3; a’ is 1 or 2

Ri is a Ci to C3 alkyl group; each of R2 to R4 is independently selected from a C5 to C20 alkyl group; and

X is N or P.

Drawings

FIG. 1 depicts MoSx catalyst after calcination under inert atmosphere.

FIG. 2 depicts scanning electron microscopy (SEM) micrographs of MoSx catalyst.

FIG. 3 depicts the powder X-ray diffraction (PXRD) diffractogram of the MoSx catalyst indexed for MoS ₂ .

Description

It has been surprisingly found that a new metal sulphide catalyst form can be produced using a simple process that results in a material that is poorly crystalline, but which may have enhanced properties over conventional metal sulphide catalysts. Thus, in a first aspect of the invention there is provided a poorly crystalline metal sulfide catalyst, wherein the catalyst comprises:

Mo and/or W in a total amount of from 25 to 35 wt%;

Ni and/or Co in a total amount of from 0 to 25 wt%;

S in an amount of from 20 to 28 wt.%;

N or P in an amount of from 0 to 5 wt%; and

C in an amount of from 10 to 54 wt.%, wherein: the Mo and W are, when present, in the form of MoS ₂ and/or M0S3 , WS ₂ and/or WS ₃ , or Mo _:: Wi - _a Sy particles, where a is from 0.99 to 0.01 and y is 2 and/or 3; and the crystallinity of the catalyst is less than 80% as measured by powder X-ray crystallography.

In embodiments herein, the word “comprising” may be interpreted as requiring the features mentioned, but not limiting the presence of other features. Alternatively, the word “comprising” may also relate to the situation where only the components/features listed are intended to be present (e.g. the word “comprising” may be replaced by the phrases “consists of’ or “consists essentially of’). It is explicitly contemplated that both the broader and narrower interpretations can be applied to all aspects and embodiments of the present invention. In other words, the word “comprising” and synonyms thereof may be replaced by the phrase “consisting of’ or the phrase “consists essentially of’ or synonyms thereof and vice versa.

The term “poorly crystalline” when used herein refers to a material that may be amorphous or has some poorly-defined crystalline peaks in a powder X-ray diffractogram. As noted above, the level of crystallinity in the catalytic material may be up to, but no more than 80% of the material. In particular embodiments that may be mentioned herein, the crystallinity of the catalyst may be less than 70%, such as less than 60%, such as less than 50% of the catalytic material. Yet more particularly, the crystallinity of the catalyst may be less than 40%, less than 30%, less than 20%, such as less than 10%. In further embodiments the material may be almost entirely amorphous or is entirely amorphous.

The measurement of the level of crystallinity can be achieved by comparing the catalyst to a purely crystalline sample of the same material measured using the same measurement parameters. As will be appreciated, the degree of crystallinity measured in this way may not be fully quantitative, so the crystallinity values above may have a degree of error in them (e.g. from 0 to 10% error, such as about 5% error). Nevertheless, it will be possible to determine whether a material is substantially crystalline or substantially amorphous based on the X-ray diffractogram of a sample catalyst without reference to a fully crystalline sample’s X-ray diffractogram and a reasonable approximation of the total crystallinity of the sample catalyst may be determined if such a diffractogram is presented.

In an alternative expression of the above aspect, there is provided a sulfide catalyst, wherein the catalyst comprises:

Mo and/or W in a total amount of from 25 to 35 wt%;

Ni and/or Co in a total amount of from 0 to 25 wt%

S in an amount of from 20 to 28 wt.%;

N or P in an amount of from 0 to 5 wt%; and

C in an amount of from 10 to 54 wt.%, wherein: the Mo and W are, when present, in the form of MoS ₂ , WS ₂ or MoaWi. _a S ₂ particles, where a is from 0.99 to 0.01 ; and at least 20% of the catalyst is in an amorphous form as measured by powder X-ray crystallography. In said embodiments, the amount of amorphous material may be greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 80%, greater than 90%, or the material may be almost entirely amorphous or is entirely amorphous.

As will be appreciated, the above version of the aspect is simply the same catalytic material, but expressed by the degree of amorphous material present. As such, it is noted that the same change in expression for the other materials listed herein is possible.

The catalyst disclosed herein is provided in a particulate form. As such, the catalyst will have a surface area that may be measured. In some embodiments of the invention, the BET surface area of the catalyst may be from 75 to 100 m ² /g. For example, the BET surface area may be 83.6 m ² /g.

In embodiments of the invention, the catalyst may comprise:

Mo and/or W in a total amount of from 25 to 35 wt%;

Ni and/or Co in a total amount of from 0 to 25 wt%

S in an amount of from 20 to 28 wt.%;

N or P in an amount of from 0 to 5 wt%; and C in an amount of from 32 to 54 wt.%.

In further embodiments of the invention, the catalyst may comprise:

Mo and/or W in a total amount of from 27 to 30 wt%;

Ni and/or Co a total amount of from 0 to 20 wt%;

S in an amount of from 22 to 24 wt%;

N or P in an amount of from 3 to 4 wt%; and C in an amount of from 42 to 48 wt%.

In further embodiments of the invention, the catalyst may comprise:

Mo in a total amount of from 25 to 35 wt%;

S in an amount of from 20 to 28 wt%;

N or P in an amount of from 1 to 5 wt%; and

C in an amount of from 32 to 54 wt.%. More particularly, the catalyst may comprise:

Mo in an amount of from 27 to 30 wt%, such as about 28.9 wt%;

S in an amount of from 22 to 24 wt%, such as about 23.2 wt%;

N or P in an amount of from 3 to 4 wt%, such as about 3.5 wt%; and C in an amount of from 42 to 48 wt%, such as about 44.4 wt%. In these embodiments, the X-ray powder diffraction pattern may display broad peaks having a 20 value of about 33° and about 59°. Further in these embodiments, the BET surface area may be about 83.6 m ² /g.

While the catalyst may be provided as an individual free-standing component, it may alternatively be provided on a solid support. Suitable solid supports include, but are not limited to silica and a ceramic (e.g. a Y-zeolite). As will be appreciated, when a solid support is included, the resulting catalyst’s BET surface area may be affected by the presence of these particles. Thus, the BET surface area may range more widely, such as from 30 to 450 m ² /g.

The catalysts disclosed herein can be made using a process that is simple and economical. Thus, in a further aspect of the invention, there is provided a method of forming a catalyst as described hereinbefore, the method comprising the steps of:

(a) providing a sulfur-containing metal organic compound or thiometallate salts; and

(b) subjecting the sulfur-containing metal organic compound or thiometallate salts to calcination at a temperature of from 300 to 400 °C under an inert gas flow for a period of time to provide the catalyst.

When used herein, the term “sulfur-containing metal organic compound or thiometallate salts” refers to any material that includes sulfur and the metals referred to hereinbefore (e.g. at least one of Mo and W, and optionally at least one of Ni and Co). Examples of suitable materials include, but are not limited to MoDTC dimer, MoDTC trimer, MoDTP and the like. In addition, ionic liquids may be used as the sulfur-containing metal organic compound or thiometallate salts. For example, the ionic liquid may have a formula I:

[RlR2R3R4X] ₂ [Bx(AxSyOz)a] I where:

A is selected from one or more of Mo and W;

B is, when present, Co and/or Ni; x is 1 to 3; x' is 0 or 1 ; y is 1 to 13; z is 0 to 3; a’ is 1 or 2

Ri is a Ci to C3 alkyl group; each of R ₂ to R ₄ is independently selected from a C ₅ to C ₂ o alkyl group; and X is N or P.

Examples of [(A _x Bi-x)xSyO _z ] that may be mentioned herein include, but are not limited to the following:

• monometallic compounds: [MoS4] ² ', [MoSg] ^2- , [MoOSs] ^2- , [M0OS3] ^2- , [Mo0 ₂ S ₂ ] ^2- , [M0O3S] ² -, [WS ₄ ] ^2- , [WOS3] ^2- , [WOS3] ^2- , [WO ₂ S ₂ ] ^2- , [WO3S] ² -;

• multimetallic compounds: [Mo ₂ S ₆ ] ^2- , [Mo ₂ S ₇ ] ^2- , [Mo ₂ S ₈ ] ^2- , [Mo ₂ S ₉ ] ^2- , [Mo ₂ Sw] ^2- , [MO ₂ SI I] ² -, [MO ₂ SI ₂ ] ² -, [MO ₂ OS ₇ ] ^2- , [MO ₂ 0 ₂ S ₆ ] ^2- , [MO ₂ 0 ₂ S ₈ ] ^2- , [MO ₃ S ₉ ] ^2- , [M03S13] ^2- , [W ₂ O ₂ S ₈ ] ^2- ; and

• heterometallic compounds:[Ni(MoS4) ₂ ] ^2- , [Ni(MoOS ₃ ) ₂ ] ^2- , [Ni(Mo0 ₂ S ₂ ) ₂ ] ^2- ,

[Ni(Mo0 ₃ S) ₂ ] ^2- , [Ni(WS ₄ ) ₂ ] ^2- , [Ni(WOS ₃ ) ₂ ] ^2- , [Ni(WO ₂ S ₂ ) ₂ ] ^2- , [Ni(WO ₃ S) ₂ ] ^2- , [Co(MoS ₄ ) ₂ ] ^2- , [Co(MoOS ₃ ) ₂ ] ^2- , [CO(MO0 ₂ S ₂ ) ₂ ] ^2- , [CO(MO0 ₃ S) ₂ ] ^2- , [CO(WS ₄ ) ₂ ] ^2- , [CO(WOS ₃ ) ₂ ] ^2- , [Co(W0 ₂ S ₂ ) ₂ ] ^2- , [Co(W0 ₃ S) ₂ ] ² -.

In the method above, the temperature for calcination may be obtained in any suitable way. This may include placing the sulfur-containing metal organic compound or thiometallate salts into an environment that has already attained the desired temperature or the sulfur-containing metal organic compound or thiometallate salts may be placed into an environment that is at or is close to ambient temperature, with the temperature being ramped up over a period of time to the desired temperature. For example, the temperature may be raised at a rate of from 3 to 4 °C per minute, such as about 3.5 °C per minute, until a target temperature is reached.

As noted hereinbefore, the temperature of the calcination step may be from 300 to 400 °C. Any temperature within this range may be used. For example, in certain embodiments that may be mentioned herein, the temperature may be about 350 °C.

The period of time in step (b) of the method above (i.e. the period of time after the desired calcination temperature has been reached) may be any suitable period of time that allows for the formation of the desired catalytic material. For example, the period of time may be from 2 to 3 hours, such as about 2.5 hours.

Any suitable inert gas may be used in the calcination step. For example, argon may be used. However, in order to minimise costs, it may be preferable to use nitrogen. As noted above, the catalyst disclosed herein may be disposed on a solid support. This may be achieved using the above method by homogenously mixing the sulfur-containing metal organic compound or thiometallate salts with a solid support prior to step (b) in the method above. Any suitable solid support may be used. For example, the solid support may be silica or a ceramic (e.g. Y-zeolite).

The catalyst disclosed herein has been shown to be useful in the generation of a deoxygenated material at low pressures. Thus, in a further aspect of the invention, there is provided a method of generating a deoxygenated organic material, the method comprising:

(a) providing a feedstock material comprising oxygen and a catalytic material suitable for converting the feedstock material comprising oxygen to a deoxygenated organic material; and

(b) contacting the feedstock material comprising oxygen with the catalytic material in a reaction vessel having a gas pressure of less than or equal to 2,000 kPa (20 bar) at a temperature of from 275 to 400 °C, such as from 300 to 380 °C, for a period of time to provide the deoxygenated organic material, wherein: the feedstock comprising oxygen is selected from one or more of the group consisting of triglycerides, fatty acids, and fatty acid esters; the gas pressure is provided solely by hydrogen gas or by hydrogen gas and an inert gas, where the hydrogen gas is provided by an external source of hydrogen gas and/or internally by the liberation of hydrogen gas from the hydrogen gas donor; and the catalytic material suitable for converting the feedstock material comprising oxygen to a deoxygenated organic material is selected from one or more of the group consisting of: a catalyst as described hereinbefore and a commercially available CoMo catalyst.

While it is demonstrated herein that a CoMo catalyst that is similar to commercially available materials works in the above method, it is noted that the catalyst described herein is significantly better at the deoxygenation reaction under the conditions stipulated above.

Any suitable gas pressure below 2,000 kPa (20 bar) may be used in the method of deoxygenation of organic materials. For example, the pressure may be about 1 ,000 kPa. As noted above, the gas pressure may be provided solely by hydrogen gas or by hydrogen gas in combination with an inert gas. While any inert gas may be used, it may be more economical to use nitrogen. In such embodiments, the main gas pressure may come from nitrogen, with hydrogen gas being generated in situ from a hydrogen gas donor. Thus in embodiments of the invention where hydrogen and an inert gas are used, the gas pressure may be provided by hydrogen gas and nitrogen, and the hydrogen gas may be provided internally by the liberation of hydrogen gas from a hydrogen gas donor. Any suitable hydrogen gas donor may be used herein in the system. As will be appreciated, a hydrogen gas donor herein should be a material that can release hydrogen gas and provide a material that can form part of the final product (i.e. the resulting material does not need to be separated from the deoxygenated organic material). In embodiments of the invention that may be discussed herein, the hydrogen gas donor may be limonene.

In embodiments of the invention where a hydrogen gas donor is present, any suitable weight ratio of the feedstock comprising oxygen to the hydrogen gas donor may be used. For example, the weight ratio of the feedstock comprising oxygen to the hydrogen gas donor is from 1 :5 to 1 :50, such as about 1 :9.

Any suitable weight ratio of the catalytic material to the feedstock may be used in the method. For example, the weight ratio of the catalytic material to the feedstock comprising oxygen may be from 1 :15 to 1 :50, such as about 1 :19.

As noted above, the feedstock material comprising oxygen may be formed from one or more triglycerides, fatty acids, and fatty acid esters. Examples of such materials include, but are not limited to palm oil (e.g. a refined palm oil), an algae oil (e.g. crude algae oil), canola/rapeseed oil, soybean oil, corn oil, sunflower oil, tallow, olive oil (e.g. virgin or used), peanut oil, castor oil, animal fats and combinations thereof.

Examples

Materials

The Y-type zeolite powder (product code HSZ-320HOA) was obtained from Tosoh. Ammonium tetrathiomolybdate, ethanol, ethyl acetate, magnesium sulfate, ammonium heptamolybdate, cobalt nitrate, y-alumina, ethylene diamine tetraacetate, dichloromethane and molybdenum (IV) sulfide were purchased from Sigma Aldrich and used without any further purification. Trioctylmethylphosphonium methyl carbonate (solution 30% in methanol) and trioctylmethylammonium methyl carbonate (solution 50% in methanol) were obtained from Proionic.

Analytical techniques

SEM Surface morphologies for the catalyst samples were analyzed using field emission scanning electron microscopy (FESEM) equipment Hitachi SU8020 at 5.0 kV, in combination with energy dispersive X-ray (EDX) spectrometry operating at 20.0 kV.

XRD

XRD analysis was done on Shimadzu X-ray diffractometer 7000 using Cu Ka radiation (A = 0.154 nm) at 40 kV tension and 40 mA current. The resulting XRD profiles were analyzed using Qualx software, with Crystallography Open Database (POW-COD) database library.

GC-MS

GC-MS (Perkin Elmer Clarus 500) equipped with a Restek Rxi-5Sil MS (0.25 MM id x 60 m) column. Helium was used as the carrier gas and dichloromethane was used as the solvent. The inlet GC temperature was set at 380 °C, with the oven temperature ramped up to 330 °C at 7 °C/min, and held at 330 °C for 15 min. Compounds were determined by comparing with spectral data available in NIST library.

Inductively coupled plasma-optical emission spectrometry (ICP-OES)

The contents of active metals Cu-Ni on support were also characterized by ICP-OES using a Perkin Elmer Optima DV 5300 spectrometer.

General procedure for deoxygenation reactions

Deoxygenation reactions were performed in a 200 mL Buchi stainless steel batch autoclave reactor. The reactor was designed for operation up to 500 °C and 350 bar, with heating means of an electric furnace. The reactor was also equipped with a single blade impeller for stirring, a type K thermocouple, an internal cooling coil, and an analogue pressure gauge.

Example 1. Synthesis of bis(trioctylmethylphosphonium) tetrathiomolybdate ([TOMP] ₂ MOS ₄ ) (G. Alonso et a/., Catal. Today 1998, 43, 117-122, US4370245)

Ammonium tetrathiomolybdate (ATTM, 1.35 g, 5.1 mmol) was dissolved in water (20 mL) to obtain a clear red solution. To this solution, a solution of trioctylmethylphopshonium methyl carbonate (30% in methanol solution, 15.8 g, 10.3 mmol) diluted in ethanol (15 mL) was added under vigorous stirring. The red viscous ionic liquid that separates was extracted with ethyl acetate and dried over MgSO4. Removal of the volatiles under reduced pressure afforded ([TOMP]2MOS4) as a deep red viscous ionic liquid (IL) in nearly quantitative yield.

FTIR (NaCI disk): 472 cm ¹ (Mo-S); UV A _max (nm, MeCN): 474, 322, 245, 200. Example 2. Synthesis of bis(trioctylmethylammonium) tetrathiomolybdate ([TOMA] ₂ MoS ₄ ) (G. Alonso et al., Catal. Today 1998, 43, 117-122, US4370245)

Bis(trioctylmethylammonium) tetrathiomolybdate was prepared from ATTM (0.68 g, 2.6 mmol) and a solution of trioctylmethylammonium chloride (2.1 g, 5.2 mmol) diluted in ethanol (15 mL) by following the protocol in Example 1 except 15 mL of water was used. The red viscous ionic liquid that separates was extracted with ethyl acetate, dried over MgSO ₄ . Removal of the volatiles under reduced pressure afforded bis(trioctylmethylammonium) tetrathiomolybdate as a deep red viscous IL in nearly quantitative yield.

FTIR (NaCI disk): 474 cm ¹ (Mo-S); UV A _max (nm, MeCN): 474, 322, 245, 200.

Example 3. Synthesis of bis(dioctadecyldimethylammonium) tetrathiomolybdate ([DODMA] ₂ MOS ₄ ) (G. Alonso et al., Catal. Today 1998, 43, 117-122, US4370245)

[DODMA] ₂ MOS ₄ was prepared from ATTM (0.98 g, 3.8 mmol) and a solution of dioctadecyldimethylammonium chloride (4.2 g, 7.5 mmol) dissolved in warm ethanol (15 mL) by following the protocol in Example 1 . The brick-red solid that separates was isolated by filtration, washed with abundant water and ethanol and dried in vacuum to afford ([DODMA] ₂ MOS ₄ in nearly quantitative yield.

FTIR (KBr pellet): 469 cnr ¹ (Mo-S); UV A _max (nm, MeCN): 474, 322, 245, 200.

Example 4. Synthesis of unsupported P Mo-oxide (P MoOx) catalyst

P MoOx catalyst was prepared by calcination of the IL ([TOMP] ₂ MoS ₄ , prepared in Example 1) in a furnace under air flow. The sample was heated to 350 °C at a rate of 3.5 °C/min and maintained at the temperature for 2 h.

Example 5. Synthesis of unsupported P Mo-sulfide (P MoSx) catalyst

P MoSx catalyst was prepared by calcination of the IL ([TOMP] ₂ MoS ₄ , prepared in Example 1) in an autoclave with nitrogen flow. The sample was heated to 350 °C at a rate of 4 °C/min and maintained at the temperature for 2.5 h.

Example 6. Synthesis of P MoSx catalyst supported on silica [TOMP] ₂ MOS ₄ IL (6.0 g, prepared in Example 1) was mixed with silica powder (4.0 g) in an autoclave. After 10 min of vigorous mixing, the mixture was heated to 350 °C at 3.5 °C/min rate under inert nitrogen flow. Then, the heating was maintained at 350 °C for 2 h.

Example 7. Synthesis of P MoSx catalyst supported on Y-type zeolites

P MoSx catalyst supported on Y-type zeolites was prepared by following the protocol in Example 6 except Y-type zeolites powder (4.0 g) was used instead of silica powder.

Example 8. Synthesis of unsupported N Mo-sulfide (MoSx-N) catalyst

MoSx-N catalyst was prepared by calcination of the IL ([TOMA] ₂ MoS4, prepared in Example 2) in an autoclave with nitrogen flow. The sample was heated to 350 °C at a rate of 3.5 °C/min and maintained at the temperature for 2 h.

Example 9. Synthesis of supported MoSx-N catalyst on silica

[TOMA] ₂ MOS4 IL (1.0 g, prepared in Example 2) was mixed with silica powder (1.0 g) in an autoclave. After 10 min of vigorous mixing, the mixture was heated to 350 °C at 5.3 °C/min rate under inert nitrogen flow. Then, the heating was maintained at 350 °C for 2 h.

Example 10. Synthesis of MoSx-N catalyst supported on Y-type zeolites

MoSx-N catalyst was prepared by following the protocol in Example 9 except Y-type zeolites powder (1 .0 g) was used instead of silica powder.

Example 11. Synthesis of Mo-sulfide catalyst supported on zirconia

ATTM (3.1 g) was mixed with zirconia powder (4.5 g) and acetone (150 mL). After 10 min of vigorous mixing, the mixture was heated to 350 °C at 5.3 °C/min rate under inert nitrogen flow. Then, the heating was maintained at 350 °C for 2 h.

Example 12. Synthesis of Mo-sulfide catalyst supported on ZSM5 zeolites

Mo-sulfide catalyst supported on ZSM5 zeolites was prepared by following the protocol in Example 11 except ZSM5 powder (4.5 g) was used instead of zirconia powder. Example 13. Synthesis of NiMo-sulfide (NiMoSx) catalyst supported on ZSM5 zeolites

ATTM (1.0 g) was mixed with ZSM5 powder (4.5 g), nickel nitrate hexahydrate (1.0 g) and acetone (150 mL). After 10 min of vigorous mixing, the mixture was heated to 350 °C at 5.3 °C/min rate under inert nitrogen flow. Then, the heating was maintained at 350 °C for 2 h.

Example 14. Synthesis of bulk CoMo catalyst at pH 5 (CoMo5)

Bulk CoMo catalyst were synthesized using known deposition precipitation (DP) method. Ammonium heptamolybdate (NH4)eM07O24 (2.648 g, 0.015 mol of Mo) and cobalt nitrate CO(NOS)2.6H20 (4.366 g, 0.015 mol of Co) were dissolved in deionised (DI) water (200 mL). While heating, 100 mL of aqueous basic solution was added dropwise with a noticeable colour change observed. For catalyst precipitation at pH 5, urea solution (30% concentration) was used as the basic solution. After addition of the basic solution, the temperature was equilibrated at 90 °C for 6 h, then cooled to ambient temperature. The suspension was vacuum filtered, followed by washing with DI water thrice and the solid catalyst sample was dried overnight at 80 °C, and then calcined in a tube furnace with flowing air (flow rate: 2 L/min) at 460 °C for 4 h.

The general procedure of catalyst sulfidation uses dimethyl disulfide (DMDS) and hydrogen (H ₂ ) gas to produce H ₂ S to sulfide the MoO into MoS ₂ . Inside a sealed autoclave reactor, the catalyst was mixed with DMDS at a minimum ratio of 1 .39 mL DMDS/g of catalyst to 50 barg of H ₂ . The reactor was heated up slowly to 150 °C and the exothermic effect can be seen where the internal reactor temperature increased 10-20 °C more than the temperature setpoint (SP) of the reactor. As a guide, DMDS decomposition temperature is between 175- 205 °C. When the internal reactor temperature appeared to be stabilised and was close to the temperature SP, the SP was increased slowly again (incremental of 15-20 °C) until the temperature SP of 230 °C. After reaching temperature SP of 230 °C, the sulfidation reaction was left for an hour, and this is considered as the first stage of catalyst sulfidation. Extra caution was taken to not exceed 245 °C to avoid coking issue and catalyst deactivation. Similar steps were repeated while increasing the temperature SP to 345 °C and maintained for an hour for the 2nd stage of sulfidation.

Example 15. Synthesis of bulk CoMo catalyst at pH 9 (CoMo9) Bulk CoMo catalyst were prepared by following the protocol in Example 14 except the catalyst precipitation was conducted at pH 9 using 10% NH ₄ OH solution.

Example 16. Synthesis of supported CoMo catalyst on alumina AI2O3

Supported CoMo catalyst were synthesized using the IWI method, with y-alumina AI ₂ O ₃ as the support. The impact of chelating agent on the catalytical deoxygenation performance was studied, where chelating agent ethylenediaminetetraacetate (EDTA) was used.

Ammonium heptamolybdate (NH^sMoyC^ (2.1 g) and cobalt nitrate Co(N0 ₃ ) ₂ .6H ₂ 0 (1.6 g) were dissolved in DI water (200 mL), together with y-AI ₂ O ₃ (4.5 g) and EDTA (0.5 g). The solution was stirred at 30 °C for 6 h. After impregnation, the catalyst were dried overnight at 80 °C, and then calcined in a tube furnace with flowing air (flow rate: 2 L/min) at 460 °C for 4 h.

Example 17. Synthesis of supported CoMo catalyst on alumina AI ₂ O ₃

Supported CoMo catalyst were prepared by following the protocol in Example 16 except without the addition of EDTA as the chelating agent. The suspension was filtered, washed, dried and calcined by following the protocol in Example 15.

Example 18. Synthesis of P MoSx catalyst from MoDTP

Commercial molybdenum dithiophosphate (MoDTP) was calcined using the procedure described in Example 5 to produce a catalyst powder.

Example 19. Hydrodeoxygenation reaction - low H ₂ pressure (LP)

The deoxygenation of palmitic acid was investigated as a general test reaction to examine catalyst suitability. Deoxygenation reactions were performed in a 200 mL Buchi steel batch autoclave reactor. The reactor is designed for operation up to 500 °C and 350 bar, with heating means of an electric furnace. The reactor was also equipped with a single blade impeller for stirring, a type K thermocouple, an internal cooling coil, and an analogue pressure gauge.

About 1 g of the catalyst was put into a 200 mL autoclave reactor containing 19 g of palmitic acid. Then, the reactor was immediately sealed and purged with H ₂ (5 times) to remove air from inside the reactor. Subsequently, the reactor was pressurized with H ₂ to 10 bar and the temperature was increased to the target reaction temperature from room temperature at a heating rate of 4 °C/min. When the reaction reaches the target temperature, the timer was started and the stirring rate was set at 1000 rpm. The trend of temperature was recorded using Buchi’s data logging software BLS3. Afterthe deoxygenation reactions had run for the targeted time duration, the heating furnace was turned off, and cooling water was supplied to the reactor via the internal cooling coil controlled by the BLS3 software.

Example 20. Hydrodeoxygenation reaction - H ₂ donor (HD)

Deoxygenation of palmitic acid was performed by following the protocol in Example 19 except the test run was conducted using limonene as the hydrogen donor.

0.26 g of catalyst was used in palmitic acid (5 g) and limonene (50 mL), making the catalyst weight ratio to palmitic acid feed to be 1 :19. Relative to limonene, the typical concentration of palmitic acid in limonene was 10.7 wt.% in all reactions, unless stated otherwise. Then, the reactor was immediately sealed and purged with N ₂ (5 times) to remove oxygen from inside the reactor. Subsequently, the reactor was pressurized with N ₂ to 5 bar and the reaction was conducted by following the protocol in Example 19.

Example 21. Hydrodeoxygenation reaction - high H ₂ pressure (HP)

Deoxygenation of palmitic acid was performed by following the protocol in Example 19 except the test run was conducted in 60 barg H ₂ pressure.

Example 22. Characterization of MoSx catalyst

The catalyst used in the present invention was produced by calcination under inert atmosphere of a tetrathiomolybdate ionic liquid with tetraalkyl phosphonium cation (see Example 5).

The product obtained from this process was a black, brittle solid with a porous sponge-like macroscopic appearance (FIG. 1). The final yield was ca. 20 %, resulting from the loss of volatile organic decomposition products of the cation. The morphology of the catalyst was studied by SEM, and the micrographs reveal a microstructure composed of randomly organized layers fanning open radiantly to form approximately spherical clusters (FIG. 2). The XRD pattern of the unsupported MoSx catalyst shows a typical profile for a poorly crystalline material, indicating the formation of disordered MoS ₂ particles (FIG. 3). Example 23. Catalytic performance of MoSx catalysts

The catalytic performance of MoSx catalysts (prepared in Examples 4-18) was assessed against CoMo (the most common catalyst used in industry for the HDO process) by following the protocol in one of Examples 19-21 .

Measurement of Brunnauer, Emmet and Teller (BET) values

Catalyst powder samples were characterized by nitrogen physisorption (Micromeritics ASAP 2020) to obtain adsorption and desorption graphs. The catalyst sample were degassed at 250 °C for 12 h. Surface areas were quantified by BET technique, while diameters and volumes of the pores were determined via volume of adsorbed nitrogen at the P/P _o of 0.985.

Results and discussion

The model reaction was the HDO of palmitic acid using D-limonene as the low-pressure hydrogen donor (Table 1).

Table 1. Catalyst compositions and performances during HDO model reaction at 370 °C, unless otherwise stated, using palmitic acid and either H2 10 barg (low pressure, LP), 60 barg (high pressure, HP) or D-limonene (hydrogen donor, HD).

*ICP-OES test done prior to sulfidation of the catalyst.

The GC-MS analysis of the reaction products obtained for MoSx catalyst showed a virtually complete depletion of palmitic acid feedstock, the formation of C15 and C16 products derived from HDO and decarbonylation/decarboxylation pathways, and aromatic peaks associated with the dehydrogenation/rearrangements of D-limonene. Under the test conditions, the MoSx catalyst outperformed the CoMo9 catalyst, showing a 95 % conversion of palmitic acid vs 88.9 % conversion for CoMo9. As a control test, the MoOx catalyst showed a much lower conversion rate of 45.5 %, indicating the intrinsic catalytic activity of metal sulfides. The conversion rate of CoMo9 increased to over 99% when high-pressure hydrogen (60 barg) was used, highlighting its usefulness for conventional industrial processes. Under the same high- pressure conditions, the MoSx catalyst achieved similar conversion and selectivity rates, which confirms its wider range of applications. The best performances for MoSx were recorded under low-pressure hydrogen (10 barg) which led to an exceptional 99% conversion rate and over 95% selectivity. A decrease in catalytic activity was however observed when the reaction temperature was decreased to 350 °C and 330 °C, resulting in conversion rates of 93 and 65 %, respectively.

MoSx catalysts supported on silica and on Y-zeolite were also prepared in Examples 6 and 7 by the same method described in Example 5 except the IL was homogeneously mixed with the supporting material priorto calcination. Both supported catalysts showed a curbed catalytic activity with the conversion rate being reduced to 22 % and 45.5 % for MoSx on silica and MoSx on Y-zeolite, respectively. Clearly, the use of bulk MoSx, where the catalytically active material is undiluted by the inert material, increases the number of active sites available for catalysis and therefore increases the conversion rate. Moreover, it cannot be ruled out that the interaction with the support might alter the micro and nanostructure of the MoSx material, resulting in lessened catalytic activity.

Example 24. Influence of starting IL cation on catalytic performance

The influence of the starting IL cation on catalytic performance was investigated by following the protocol in Example 20. An analogue of MoSx (MoSx-N) was prepared in Example 8.

Results and discussion

No noticeable difference in the final material was observed and the MoSx-N catalyst showed excellent activity for HDO of palmitic acid with D-limonene as the hydrogen donor. These results indicate that the properties of the catalysts are mainly dictated by the presence of the M0S2 component and the size of the cation ratherthan the type of “onium” salt (i.e., ammonium vs phosphonium).

Example 25. Catalytic performance of MoSx catalyst for HDO of oils

The performance of MoSx catalyst (prepared in Example 5) in HDO was tested beyond the model reaction of free fatty acid. Thus, three different oils, namely refined palm oil, crude algae oil and sunflower oil, were used as feedstock for HDO by following the protocols in Examples 20 and 21.

Results and discussion A conversion rate in over 99% was recorded in all cases (Table 2). This confirms the applicability of the method with outstanding results to real case systems.

Table 2. Results of the HDO reaction for P-MoSx catalyst using different feedstock.