Biopropane production process

Abstract

A process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises contacting: (a) a feedstream

Description

FIELD OF THE INVENTION The present invention is in the field of processes for the production of biopropane, and catalysts for use in said processes. BACKGROUND OF THE INVENTION Propane is a chemical that is vital to the modem global economy. Propane has many uses such as a component of liquefied petroleum gas (LPG), as a refrigerant, as a propellant for aerosol products such as air fresheners and shaving creams, and as a feedstock in the chemical industry. A principal use of propane is as a component of LPG. At the end of 2018, LPG was estimated to be consumed in an amount of around 300 million tonnes per year. LPG is used in a variety of applications such as fuel for heating appliances, cooking equipment such as outdoor stoves and gas barbeques and certain vehicles. Propane is very often the main and in some cases sole component of LPG. It is the preferred component as it has a much lower boiling point (-42C) than for example butane (-IC) allowing it to be used for heating in virtually all cold climates. Historically, propane has been derived from fossil ftiel sources. For example, propane can be extracted or manufactured during the refining of petroleum or wet natural gas. or extracted from petroleum and natural gas streams as they emerge from the ground. Since conventionally manufactured propane is a fossil fuel, in order to reduce net carbon emissions, there has recently been increased interest in replacing propane derived from fossil fuel sources with propane derived from biological sources (biopropane). Biopropane has a much lower carbon footprint than conventionally derived propane. There is thus great interest from the propane industry and decarbonisation-proponents to expand production volumes of biopropane for various uses and in particular for use in biologically derived LPG (BioLPG). Various types of processes have been suggested for the production of BioLPG. These include the following classes of process: i) hydrotreating of bio-oils such as waste vegetable oils; (ii) dehydrogenation of bio-oils and glycerine; iii) fermentation of sugars; iv) hydrolysis and fermentation of cellulosic biomass; v) digestion such as anaerobic digestion by bacteria of wet organic wastes; vi) gaseous conversion and synthesis of cellulosic biomass or organic waste; and vii) liquid conversion and synthesis of cellulosic biomass and organic waste. Many of these processes manufacture bioLPG in low yield as a by-product only, and are principally directed to the manufacture of different products. Additionally, many of these suggested processes have only been successfully demonstrated in the laboratory or remain at the concept stage, and have not been successfully commercialised. Of the processes discussed above, only hydrotreating of bio-oils has been successfully commercialised. Hydrotreatment is thus the only significant source of BioLPG / biopropane production. Hydrotreating of bio-oils produces biopropane as a by-product only, and is principally directed to the production of HVO (hydrogenated vegetable oil) diesel. In such hydrotreatment processes, the ratio of renewable diesel to biopropane produced is ty pically around 9:1 to 10:1. If the target product is desired to be used for Sustainable Aviation Fuel (SAF). then further processing involving cracking and isomerisation can result in bio-isobutane, another component of bioLPG. Some of these hydrotreatment processes involve the hydrotreatment of a purely bio-oil feedstock. However, many processes involve mixing bio-oil with petroleum intermediates to form a blend and hydrotreating the blend to form a mixture of diesel and renewable diesel, and a small amount of biopropane / BioLPG by-product. An in-depth discussion of the various processes known for or suggested for BioLPG and biopropane production is provided in Process Technologies and Projects for BioLPG. Eric Johnson. Energies, 2019, 12, 250. There is thus a need for new commercially viable routes for the production of biopropane. In particular, there is a need for biopropane production processes that produce biopropane in high yield. It is known to use bio-derived acetone as a feedstock for a hydrodeoxygenation reaction for the production of hydrocarbons. However, in such processes, biopropane is only produced as a byproduct in low yield. The major products of these known processes are longer chain alkanes, olefins and BTX aromatics. Mechanistic Insights into Hydrodeoxygenation of Acetone over Mo / HZSM-5 Bifunctional Catalyst for the Production of Hydrocarbons, Miao et al., Energies 2022, 15, 53 discloses a process in which bio-derived acetone is converted to hydrocarbons by hydrodeoxygenation in the presence of a bifunctional HZSM-5 / MoCh catalyst. Propane is produced in low yields of less than 20%. The major products of the process are BTX aromatics and olefins. Exploring Iron Oxide Catalysts for Acetone Hydrodeoxygenation: Making use of Earth-Abundant Resources, Nunes et al.. ChemRxiv 2024 discloses a process in which bio-derived acetone is converted to hydrocarbons by hydrodeoxygenation in the presence of an iron oxide nanopowder. Propane is produced in low yields of less than 40% with other products of the process being longer and shorter chain alkanes and olefins. Enhanced Bronsted Acidity and Hydrogenating Sites Generated on MoOi during Acetone Hydrodeoxygenation., Bafero et al., ChemCatChem 2023, 15 discloses processes in which bioderived acetone is converted to hydrocarbons by hydrodeoxygenation in the presence of a molybdenum oxide (MoOi) catalyst. Propane is produced in low yields of less than 40% with the other reaction products being olefins, isopropyl alcohol, longer chain alkanes and aromatics. The processes described above are not principally concerned with the production of biopropane, but with the production of a wide variety of hydrocarbon products. Biopropane is only formed in the processes as a by-product in low yield. The process parameters and catalysts used in these processes are not specifically adapted and tailored for the production of biopropane or BioLPG. Thus there is a need for an economically viable process for producing biopropane in high yield from biologically derived feedstocks. SUMMARY OF THE INVENTION The present invention is based on the surprising finding that biologically derived C3 aliphatic alcohols, C3 aliphatic ketones and C3 aliphatic aldehydes can be used as feedstocks in processes for the preparation of biopropane with high selectivity and yield. It has surprisingly been found that, using certain reaction conditions and catalyst systems, these feedstocks can be converted to propane via a hydrodeoxygenation reaction with high yields and with propane selectivity of 90% or more, and in some cases 95% or more. This represents a significant improvement over processes known in the art for producing biopropane where biopropane is produced with substantially lower yield and selectivity. In the invention, a hydrodeoxygenation process is carried out to convert a C3 aliphatic ketone, or C3 aliphatic aldehyde to propane. In a first step, hydrogen and a C3 aliphatic ketone or aldehyde feedstream react in the presence of an alkali metal doped nickel catalyst material to fonn a C3 aliphatic alcohol via a hydrogenation reaction. The C3 aliphatic alcohol is then dehydrated to form a C3 aliphatic olefin in a reaction catalysed by the zeolite or heteropolyacid catalyst. The olefin is then hydrogenated to propane in a final step catalysed by a nickel catalyst material (which may be the same or different nickel catalyst material as used in the first step of the process). An example of a process according to the invention using acetone as a feedstock is depicted below. Also according to the invention are processes where the starting material is a C3 aliphatic alcohol such as isopropyl alcohol. In such processes, the first stage of the reaction depicted in the figure below is not carried out. het eropofy acid According to a first aspect of the invention, there is provided a process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises contacting: (a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of a catalyst system comprising: (i) an alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof: and wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm. The process of the first aspect of the invention is a one pot hydrodeoxygenation reaction. Such a one pot process is particularly useful as all steps of the hydrodeoxygenation can be carried out in a single reactor meaning that multiple reactors are not required. This can provide reduced capital expenditures and also save space when compared to process that require multiple reactors. Typically, the feedstreams (a) and (b) are contacted at a temperature of from 120 °C to 250 °C. Preferably, the feedstreams (a) and (b) are contacted at a temperature of from 150 °C to 200 °C. Typically, the feedstreams (a) and (b) are contacted at a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) are contacted at a pressure of from 8 atm to 15 atm. Typically, the feedstreams (a) and (b) are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. The process may be carried out as a continuous process. Alternatively, the process may be carried out as a batch process. In preferable embodiments, the process is carried out as a continuous flow process. Typically, the feedstream (a) comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof is introduced at a flow rate of from 25 pl per minute to 100 pl per minute, per 2 grams of a total of (i) alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof present. Typically, the feedstream (b) is introduced at concentration of 2 to 5 moles, preferably 2.5 to 4 moles, most preferably 2.6 to 3.0 moles, per mole of feedstream (a). Typically, the feedstreams (a) and (b) are contacted at a molar ratio of from 2:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably at a molar ratio of from 2.5:1 to 5:1; and more preferably at a molar ratio of from 2.5:1 to 4:1; and most preferably at a molar ratio of from 2.6:1 to 3:1. It is preferred that a molar ratio of at least 2:1 (moles ofhydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones) is used in order to provide a high biopropane yield and selectivity for the process. A first molar amount ofhydrogen is used in the first step of the reaction to react with the ketone / aldehyde and convert it to the alcohol. A second molar amount ofhydrogen is then used in the final step of the process to reduce the olefin to propane. Despite theoretically, a molar ratio of only 2:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones) being necessary for complete conversion of the acetone to propane, it has been found by the inventors that a molar ratio of at least 2.5:1 provides particularly high biopropane yield and selectivity. Typically, the catalyst system is pre-treated with hydrogen to reduce the alkali metal doped nickel catalyst material. Typically, the catalyst system is pre-treated with hydrogen at a temperature of from 150 °C to 300 °C. and preferably from 200 °C to 250 °C. Preferably, this step is carried out for a time period of from 1 hour to 5 hours. Preferably, the pre-treatment further comprises contacting the catalyst system with an inert gas at a temperature of from 250 °C to 400 °C for a time period of greater than 30 minutes. Any inert gas may be used but preferably the inert gas comprises argon. The feedstream (a) may be derived from any suitable biological source. Suitable biological sources of C3 aliphatic aldehydes and ketones will be apparent to those of skill in the art given the benefit of the present disclosure. Preferably, the feedstream (a) is derived from fermentation or bio-generation, such as derived from fermentation of flue gases or bio-generated syngas. In some embodiments, the one or more C3 aliphatic ketones or aldehydes are produced from fermentation of biological organic material, such as fennentation of cellulosic material. Processes for the fennentation of cellulosic material so as to provide biologically derived C3 ketones or aldehydes are known in the art. In other embodiments, the one or more C3 aliphatic ketones or aldehydes are derived from recycled carbon. For example, the one or more C3 aliphatic ketones or aldehydes may be produced from fermentation of flue gases or bio-generated syngas. Flue gases are the waste product stream of many industrial processes. Flue gases and syngas comprise hydrogen, carbon monoxide and carbon dioxide. These gases can be converted by microorganisms in fermentation processes into C3 aliphatic ketones or aldehydes. The terms biopropane and BioLPG as used herein are to be understood in accordance with the normal meanings of the terms in the art. BioLPG / biopropane is propane / LPG produced from a feedstock that is derived from a biological source instead of fossil fuels. The term derived from a biological source as used herein is used to refer to material that is directly obtained from a biological source or indirectly obtained from a biological source. For example, the term derived from a biological source as used herein encompasses materials obtained by a chemical process where the starting material of the chemical process is obtained from a biological source. For example, where a material obtained from a biological source is chemically processed into a chemical intermediate prior to conversion of the intermediate into propane or LPG, the propane or LPG is still considered to be biopropane or BioLPG. The tenns biopropane and BioLPG as used herein are also used to refer to propane or LPG produced from a feedstock that has been produced by a microbial process such as fermentation. The feedstock for the microbial process such as fermentation may itself have been derived from fossil fuels, for example carbon dioxide or carbon monoxide obtained from the combustion of fossil fuels. LPG / propane produced by such a process is considered to be BioLPG / biopropane since the feedstock of the propane / LPG production process is a product of a biological process that has a feedstock that is a gas obtained from the combustion of fossil fuels, that would otherwise be released into the atmosphere and contribute to atmospheric carbon levels. Typically, the feedstream (a) comprises one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream. Preferably, the feedstream (a) comprises acetone. Preferably, the acetone is present in the feedstream (a) in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream. In some instances, the feedstream (a) may further comprise a C3 aliphatic alcohol such as isopropyl alcohol. Accordingly, in some instances, the feedstream (a) comprises acetone and one or more C3 aliphatic alcohols such as isopropyl alcohol. Where a C3 aliphatic alcohol such as isopropyl alcohol is also present in the feedstream (a), preferably the C3 aliphatic alcohol is also biologically derived, such as derived from the biological sources discussed above. In some instances, the feedstream (a) further comprises water. Typically, the water is present in an amount of up to 20% by weight of the total weight of components of the feedstream; preferably in an amount of up to 10% by weight of the total weight of components of the feedstream; more preferably in an amount of up to 5% by weight of the total weight of components of the feedstream; and most preferably in an amount of up to 3% by weight of the total weight of components of the feedstream. In some instances, the water is present in an amount of from 0.5% to 20% by weight of the total weight of components of the feedstream. In these instances, preferably, the water is present in an amount of from 1% to 10% by weight of the total w eight of components of the feedstream; more preferably from 3% to 10% by weight of the total w eight of components of the feedstream; and most preferably from 3% to 5% by weight of the total weight of components of the feedstream. It has surprisingly been found that including water in the feedstream (a) further improves the propane selectivity of the process and increases the conversion of the C3 aliphatic ketones and / or aldehydes present in feedstream (a). The presence of water in feedstream (a) has also surprisingly been found to prolong the operational lifetime of the catalyst system used in the process. Without being limited by theory, it is believed that the presence of water in the feedstream plays a key role in the first step of the reaction in the conversion of ketones and / or aldehydes to alcohols, and also in the conversion of C3 aliphatic olefins to propane. The presence of water in the feedstream (a) has been found to improve percentage conversion of the ketone and / or aldehyde and also to improve selectivity for the formation of C3 aliphatic alcohols over undesirable side products such as C6 aldol condensation products formed by the condensation of two C3 aliphatic ketone or aldehyde molecules. The advantages associated with including water in the feedstream (a) are particularly prevalent where water is included in feedstream (a) in the amounts specified above. The advantages associated with the inclusion of water in feedstream (a) are particularly useful in the process of the invention, since the biologically derived C3 aliphatic ketones and aldehydes often contain minor amounts of w ater left over from the process streams from w hich they are derived. There is no need for feedstream (a) to be pre-treated so as to provide a completely water free feedstream as is the case with certain industrial processes. Indeed, this is in fact undesirable due to the advantages associated with inclusion of water in feedstream (a). The catalyst system comprises (i) an alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. As discussed above, the (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof is included so as dehydrate the C3 aliphatic alcohol to a C3 aliphatic olefm. Without being limited by theory, it is believed by the inventors that it is the acidic nature of these catalysts that enables them to be effective catalysts for dehydration of the C3 aliphatic alcohol to C3 aliphatic olefins. In some instances, the catalyst system comprises a heteropolyacid catalyst material. The term heteropolyacid catalyst material as used herein is used consistent with its normal meaning in the art. Heteropolyacids typically comprise three or more transition metal oxyanions linked together by shared oxygen atoms to form a three-dimensional framework which is then present in its solid acid form. Any suitable heteropolyacid catalyst material known in the art may be used in the process of the invention. Examples of heteropolyacid materials that may be used include Silicotungstic acid (H4SiWi204o.nH20). phosphomolybdic acid (H3Moi2P04o.nH20) and phosphotungstic acid (H3Wi2PO40.nH2O). Preferably, where the catalyst system comprises a heteropolyacid catalyst material, the heteropolyacid catalyst material comprises a tungstophosphoric acid and more preferably 12-tungstophosphoric acid (HPW). Preferably, the catalyst system comprises one or more zeolite catalyst materials. The term zeolite catalyst material as used herein is used consistent with its normal meaning in the art. Any suitable zeolite catalyst material known in the art may be used in the process of the invention. The use of zeolites are preferred over the use of heteropolyacids as they have been found by the inventors to provide better conversion of C3 aliphatic alcohols to C3 aliphatic olefins and better propane selectivity than when heteropolyacid catalyst materials are used. Typically, the one or more zeolite catalyst materials comprise one or more ZSM5 zeolite materials, one or more Zeolite Y materials, one or more MCM zeolite materials, one or more SSZ-13 zeolite materials, or a combination thereof. Preferably, the one or more zeolite materials comprise one or more ZSM5 zeolite materials, one or more Zeolite Y materials, or a combination thereof. It has been found that ZSM5 zeolite materials and Zeolite Y zeolite materials provide better conversion of the C3 aliphatic alcohol to C3 aliphatic olefm than other zeolites. The use of these zeolites has also been found to provide better propane selectivity than other zeolite materials. Where the one or more zeolite materials comprise one or more ZSM5 zeolite materials, one or more Zeolite Y materials, or a combination thereof, typically, the one or more ZSM5 zeolite materials or one or more Zeolite Y materials have an Si / Al ratio of from 2 to 500; preferably from 5 to 400; more preferably from 20 to 150: still more preferably from 50 to 100; and most preferably from 70 to 90. In some instances, the one or more zeolite materials may comprise one or more promoter elements. Typically, such promoter elements are included in the one or more zeolite materials in order to alter the strength or number of acid sites of the zeolite material catalyst which may have an affect upon the catalytic activity of the one or more zeolite materials. Zeolite materials may be promoted by the addition of additional elements to the zeolite structures. Zeolites are typically represented by the formula Mz / nO.AhCh.xSiCh.yHhO. In said structures, M is a cation; n is the valence of the cation; x is the Si: Al ratio; and y is the number of water molecules present in the structure. The alumina and silica (AI2O3 and SiO?) units are typically present in a porous framework of the zeolite structure, with the cations and water molecules present in the pores. A promoted zeolite material is one where small quantities of an additional element (other than Aluminium, Oxygen or Silicon) have been chemically introduced into the zeolite structure. A promoted zeolite material may have different properties in relation to the unpromoted zeolite material. For example, the catalytic activity in a given reaction, selectivity for certain products, acidity, and many other chemical properties of the zeolite may be tailored by the introduction of promoter elements to the zeolite structure. Preferably, the one or more catalyst materials comprise one or more boron and / or phosphorus promoted zeolite materials. More preferably, the one or more zeolite catalyst materials comprise a phosphorus promoted ZSM5 zeolite material; a phosphorus promoted Zeolite Y material, a phosphorus promoted MCM zeolite material, a phosphorus promoted SSZ-13 zeolite material, or a combination thereof. Most preferably, the one or more zeolite catalyst materials comprise a phosphorus promoted ZSM5 zeolite material; a phosphorus promoted Zeolite Y material, or a combination thereof. It has been found that phosphorus promotion of the one or more zeolite materials further improves the conversion of C3 aliphatic aldehydes / ketones and further enhances propane selectivity. Without being limited by theory, it is believed that phosphorus promotion affects the number of acid sites / aciditj- of each acid site in the zeolite material in a manner that enhances conversion of the ketone / aldehyde reactant and promotes selectivity for propane. Where present, the one or more phosphorus promoted zeolite materials typically comprise from 0.1% to 5% by weight phosphorus; and preferably from 0.5% to 3% by weight phosphorus Accordingly, preferably, the one or more zeolite materials comprise a phosphorus promoted ZSM5 zeolite material, phosphorus promoted Zeolite Y material, phosphorus promoted MCM zeolite material, or phosphorus promoted SSZ-13 zeolite material comprising from 0. l%to 5% by weight phosphorus; and preferably from 0.5% to 3% by weight phosphorus. Heteropolyacids and zeolite materials discussed above such as zeolite Y and ZSM5 are commercially available. Phosphorus promoted zeolite materials and other promoted zeolite materials may be prepared from the corresponding unpromoted materials by methods known in the art which will be apparent given the benefit of the present disclosure. For example, incipient wetness processes may be used. In highly preferred instances, the catalyst system comprises one or more zeolite catalyst materials comprising a phosphorus promoted ZSM5 zeolite material or a phosphorus promoted Zeolite Y material; wherein the phosphorus promoted ZSM5 zeolite material or phosphorus promoted Zeolite Y material comprises from 0.5% to 3% by weight phosphorus and has a Si / Al ratio of from 50 to 100. The catalyst system comprises an alkali metal doped nickel catalyst material. As discussed above, this catalyst material is important for the first step of the process of hydrogenating the aldehyde / ketone to an alcohol and also the third step of hydrogenating the olefin to propane. Nickel and its compounds are known as hydrogenation catalysts along with many other transition metals such as palladium, copper, cobalt, iridium, platinum, rhodium and ruthenium. Surprisingly, in the process of the invention, it has been found by the inventors that nickel is better at hydrogenating C3 aliphatic olefins to propane than the metals discussed above. Using nickel instead of the other metals, improved propane selectivity was found to be provided. Another advantage of using nickel is that it is cheaper than precious metals such as palladium, platinum, iridium, rhodium and rhenium. The nickel catalyst material is doped with one or more alkali metals. Where the feedstream (a) comprises one or more C3 aliphatic ketones or C3 aliphatic aldehydes, the doping of the catalyst material has been found to be critical for providing sufficiently long catalyst lifetime for industrial utility and to provide a commercially viable process. Without being limited by theory, it is believed that the alkali metal modifies the electronic properties of nickel. Where the nickel catalyst material comprises a carrier, binder or support material as discussed in further detail below, it is believed that the alkali metal neutralizes acid sites on the support, carrier or binder material. These effects are believed to effectively extend the catalyst lifetime of the nickel catalyst material and also promote high levels of C3 aliphatic ketone / aldehyde conversion and high propane selectivity. The presence of the alkali metal in the nickel catalyst material is believed to be critical for the first step of the process of the invention for the conversion of C3 aliphatic ketone / aldehyde to C3 aliphatic alcohol. It is believed that where an alkali metal doped material is used, the formation of undesirable aldol condensation products in the first stage of the reaction is suppressed. Alkali metal doping the nickel catalyst material has also been found to promote conversion of C3 aliphatic olefin to propane in the final step of the process. Thus, alkali metal doping the nickel catalyst material still provides benefits to the process where feedstream (a) comprises a C3 aliphatic alcohol as in the fourth and fifth aspects of the invention as discussed in further detail below. The alkali metal doped nickel catalyst material may comprise the alkali metal in any suitable amount. Typically, the alkali metal doped nickel catalyst material comprises from 0.5% to 20% by weight of a total of the one or more alkali metals: preferably from 1% to 10% by weight of a total of the one or more alkali metals; and more preferably, from 2% to 8% by weight of a total of the one or more alkali metals. Typically, the alkali metal doped nickel catalyst material comprises one or more of lithium, sodium, potassium, rubidium, caesium, or a combination thereof. Preferably, the alkali metal doped nickel catalyst material comprises one or more of lithium, sodium, potassium, or a combination thereof. More preferably, the alkali metal doped nickel catalyst material comprises sodium in an amount of from 0.5% to 20% by weight: preferably from 1% to 10% by weight: and most preferably from 2% to 8% by weight. Any nickel catalyst material suitable for hydrogenation of ketones / aldehydes to alcohols and hydrogenation of olefins to alkanes known in the art may be used. Examples of suitable catalyst materials will be apparent given the benefit of the present disclosure. Typically, the nickel catalyst material comprises a nickel compound such as a nickel salt. Preferably, the nickel catalyst material comprises an ionic compound of nickel with nickel in the +2 oxidation state. Preferably, the nickel catalyst comprises nickel oxide and more preferably nickel (II) oxide. Preferably, the nickel compound comprises nickel oxide and more preferably nickel (II) oxide. Most preferably, the nickel catalyst material comprises sodium doped nickel oxide such as sodium doped nickel (II) oxide. Typically, the alkali metal doped nickel catalyst material comprises a carrier, binder, or support material. Any suitable carrier, binder or support materials known in the art may be used. Preferably, the alkali metal doped nickel catalyst material comprises an alumina support material. Where the nickel catalyst material comprises a carrier, binder, or support material, preferably, the alkali metal doped nickel catalyst material comprises a carrier, binder, or support material present in an amount of from 0.1% to 40% by weight of the alkali metal doped nickel catalyst material; and more preferably in an amount of from 5% to 40% by weight of the alkali metal doped nickel catalyst material. Suitable commercially available nickel catalyst materials known in the art as catalysts for hydrogenation may be used. Alkali metal doped nickel catalyst materials may be easily prepared from the commercially available nickel catalyst materials by processes known in the art such as incipient wetness processes where the nickel catalysts are reacted with solutions of alkali metal salts. Other suitable processes known in the art may also be used. An example of a commercially available catalyst that may be used is HTC Ni 500 from Johnson Matthey Catalysts that comprises nickel oxide on an alumina support. Catalysts such as this may then be reacted with aqueous solutions of alkali metals (or by other known techniques) to provide the alkali metal doped nickel catalyst material. The catalyst system may comprise the (i) alkali metal doped nickel catalyst material and the (ii) zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof in any suitable mass ratio for effective conversion of the C3 aliphatic aldehydes / ketones to propane. Typically, the catalyst system comprises the (i) alkali metal doped nickel catalyst material and the (ii) zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof in a mass ratio of from 1:1 to 1:5; and preferably from 1:1.5 to 1:3. In some instances, the catalyst system comprises a catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. In some instances, the catalyst bed layer comprises a single catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. However, preferably, the catalyst system comprises: a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; and a second catalyst bed layer comprising both a nickel catalyst material and the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. In this configuration, typically, at least a portion of the feedstream (a) forms one or more aliphatic C3 alcohols on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 alcohols; and wherein the stream comprising one or more aliphatic C3 alcohols subsequently contacts the second catalyst bed layer. This double layer configuration is preferred over having just a single catalyst bed layer comprising both the alkali doped nickel catalyst material and zeolite material or heteropolyacid catalyst material. This is because it has been found by the present inventors that the acidic nature of the zeolite catalyst material or heteropolyacid material can promote the formation of unwanted aldol condensation products in the first stage of the reaction (conversion of aliphatic ketone / aldehyde to alcohol). By including a first layer of nickel catalyst material without zeolite or heteropolyacid, the formation of unwanted aldol condensation products is minimised in the first stage of the reaction. The C3 aliphatic alcohol formed in the first stage of the reaction can then pass to the second layer that comprises nickel catalyst material and zeolite catalyst material and / or heteropolyacid catalyst material for the second and third stages of the reaction to occur. In some instances, the catalyst system comprises: a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; a second catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a third catalyst bed layer comprising a nickel catalyst material. Typically, in these instances, at least a portion of the feedstream (a) forms one or more aliphatic C3 alcohols on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 alcohols; and the stream comprising one or more aliphatic C3 alcohols subsequently contacts the second catalyst bed layer to form a stream comprising one or more aliphatic C3 olefins; and the stream comprising one or more aliphatic C3 olefins subsequently contacts the third catalyst bed layer. This configuration is also preferred to the configuration of a single catalyst bed layer as described above, since it also allows suppression of the undesired aldol condensation products in the first stage of the reaction as discussed above. In the instances described in the paragraphs above where the catalyst system comprises more than one catalyst bed layer, preferably, the first catalyst bed layer and second catalyst bed layer and / or the second catalyst bed layer and third catalyst bed layer are separated by a void or by a separation material. The separation material may be any suitable separation material such as an inert separation material. Preferably the separation material comprises silicon carbide. The term void as used herein is used to refer to a space or empty section of a reaction chamber or conduit between the catalyst bed layers through which the gas streams involved in the process may flow from the first catalyst bed layer to subsequent catalyst bed layers. In the instances described above where the catalysts are arranged in different layers, the nickel catalyst material present in the second layer (such as in the two layer configuration discussed above) or present in the third layer (such as in the three layer configuration discussed above) is preferably an alkali metal doped nickel catalyst material such as an alkali metal doped nickel catalyst material discussed above. More preferably, the nickel catalyst material present in the second or third catalyst bed layers is the same as the alkali metal doped nickel catalyst material present in the third layer. However, in alternative embodiments, nickel catalyst material present in the second or third catalyst bed layers is different to the alkali metal doped nickel catalyst material present in the first layer. For example, it is not essential that the nickel catalyst material present in the second or third layers is alkali metal doped. As discussed above, whilst it is preferable for the third stage of the hydrodeoxygenation reaction that the nickel catalyst material is alkali metal doped, it is not essential. It is only for the first stage of the reaction that an alkali metal doped catalyst is essential. Where the nickel catalyst material in the second or third layer is not alkali metal doped, the nickel catalyst materials discussed above can be used in non-alkali metal doped form. The process of the first aspect of the invention may be carried out in any suitable reaction vessel. The suitable reaction vessel may comprise the catalyst in any suitable configuration or set-up for effectively earn ing out the process of the invention. For example, the reaction vessel may comprise a fixed bed reactor. Preferably, the process of the first aspect of the invention is carried out in a fixed bed reactor. The term fixed bed reactor as used herein is also used to encompass multi-tubular type reactors. Multi-tubular type reactors may be used for example where the catalyst system comprises more than one catalyst bed layer. In these instances, different tubes of the multi-tubular reactor may comprise the different catalyst bed layers. Other suitable features of the reaction vessel(s) and means for implementing the process of the invention are those ty pically used in the art for a catalytic process such as the process of the invention. In some instances, the process of the invention may comprise introducing the (a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen into a reaction vessel comprising the catalyst system and contacting the feedstreams and catalyst system within the reaction vessel before recovering a product stream from the reaction vessel, where the product stream comprises propane. According to a second aspect of the invention, there is provided a process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises: (i) contacting (a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of an alkali metal doped nickel catalyst material, wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm: and (ii) contacting the product of step (i) with a catalyst system comprising (I) a nickel catalyst material, and (II) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm. Preferably, the alkali metal doped nickel catalyst material used in step (i) is as described above in accordance with the first aspect of the invention. The nickel catalyst material used in step (ii) of the process may be an alkali metal doped nickel catalyst material as described above in accordance with the first aspect of the invention. In some instances, the nickel catalyst material used in step (ii) may be the same nickel catalyst material as used in step (i) of the process. This is preferred as it means that only one type of nickel catalyst material needs to be procured for the process. Additionally, whilst alkali metal doping the nickel catalyst material is only essential for step (i) of the process, it still provides certain advantages to the third stage of the process as discussed above in the context of the first aspect of the invention. However, in other instances, the nickel catalyst material used in step (ii) may be different to the nickel catalyst material used in step (i). Any nickel catalyst material suitable for hydrogenation of ketones / aldehydes to alcohols and hydrogenation of olefins to alkanes known in the art may be used in step (ii) of the process. Examples of suitable catalyst materials will be apparent given the benefit of the present disclosure. Typically, the nickel catalyst material comprises a nickel compound such as a nickel salt. Preferably, the nickel catalyst material comprises an ionic compound of nickel with nickel in the +2 oxidation state. Preferably, the nickel catalyst comprises nickel oxide and more preferably nickel (II) oxide. Preferably, the nickel compound comprises nickel oxide and more preferably nickel (II) oxide. Typically, the nickel catalyst material used in step (ii) comprises a carrier, binder, or support material. Any suitable carrier, binder or support materials known in the art may be used. Preferably, the nickel catalyst material comprises an alumina support material. Preferably, the nickel catalyst material used in step (ii) is alkali metal doped. However, this is not essential. Preferably, the catalyst system in step (ii) is as described above in accordance with the first aspect of the invention. Preferably, the feedstream (a) is as described above in accordance with the first aspect of the invention. Typically, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 120 °C to 250 °C. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 150 °C to 200 °C. Typically, the feedstreams (a) and (b) in step (i) are contacted at a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a pressure of from 8 atm to 15 atm. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the product of step (i) and catalyst system are contacted at a temperature of from 120 °C to 250 °C and preferably at a temperature of from 150 °C to 200 °C. Typically, the product of step (i) and catalyst system are contacted at a pressure of from 5 atm to 25 atm and preferably at a pressure of from 8 atm to 15 atm. Preferably, the product of step (i) and catalyst system are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the product of step (i) and catalyst system are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Preferably, the process steps are carried out continuously as a continuous flow process. Typically, the process comprises introducing the feedstream (b) at a flow rate of from 25 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in steps (i) and (ii). Typically, the process comprises introducing the feedstream (a) at a flow rate of from 25 pl per minute to 100 pl per minute, per gram of total nickel catalyst material present in steps (i) and (ii). Typically, the feedstreams (a) and (b) in step i), are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones). Preferably, the feedstreams (a) and (b) in step (i) are contacted at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones). Step (ii) of the process may further comprise contacting the product of step (i) and catalyst system with an additional hydrogen feedstream. In these instances, less hydrogen may be used in step (i) as only enough hydrogen is needed for step (i) of the process since the process further comprises introducing additional hydrogen at a later stage for step (ii). However, preferably, the total amount of hydrogen used in the process (i.e. used in steps (i) and (ii)) is a molar ratio of from 2:1 to 10:1 (total moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably a molar ratio of from 2.5:1 to 5:1; more preferably a molar ratio of from 2.5:1 to 4:1; and most preferably a molar ratio of from 2.6:1 to 3:1. The process may further comprise pre-treating the alkali metal doped nickel catalyst material and / or catalyst system as discussed above in the context of the first aspect of the invention. The process of the second aspect of the invention may be carried out in a single reaction vessel. For example, the process may comprise introducing the feedstreams (a) and (b) to a reaction vessel where the feedstreams contact the alkali metal doped nickel catalyst material to provide an intermediate product stream comprising one or more C3 aliphatic alcohols which then contacts the catalyst system comprising (I) a nickel catalyst material, and (II) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to provide a product stream comprising propane. The process may then comprise recovering the product stream comprising propane from the reaction vessel. It is preferred that the process of the second aspect of the invention occurs in one reaction vessel so as to provide a "one pot" process thus reducing the capital expenditure of the process and space taken up by components in a chemical plant. However, the process may also be carried out in two reaction vessels as discussed below. In some instances, the process of the second aspect of the invention may be carried out in two separate reaction vessels. Such a process may comprise introducing the feedstreams (a) and (b) to a first reaction vessel where the feedstreams contact the alkali metal doped nickel catalyst material to provide an intermediate product stream comprising one or more C3 aliphatic alcohols. The intermediate product stream may then be recovered from the first reaction vessel and introduced into a second reaction vessel comprising a catalyst system comprising (I) a nickel catalyst material, and (II) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to contact the catalyst system and provide a product stream comprising propane. The product stream comprising propane may then be recovered from the second reaction vessel. As discussed above, the process may comprise introducing a second hydrogen feedstream (ii) into the second reaction vessel to contact the catalyst system and intennediate feedstream. The process of the second aspect of the invention may be carried out in any suitable reaction vessel(s). The suitable reaction vessel(s) may comprise the catalyst in any suitable configuration or set-up for effectively carrying out the process of the invention. For example, the reaction vessel may comprise a fixed bed reactor. Alternatively, the reaction vessel may comprise a fluidised bed reactor. Preferably, the process of the second aspect of the invention is carried out in one or more fixed bed reactors. The tenn fixed bed reactor as used herein is also used to encompass multi-tubular type reactors. Where multi-tubular type reactors are used, different tubes of the multi-tubular reactor may comprise the different catalyst bed layers. Other suitable features of the reaction vessel(s) and means for implementing the process of the invention are those typically used in the art for a catalytic process such as the process of the invention. According to a third aspect of the invention, there is provided a process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises: (i) contacting (a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of an alkali metal doped nickel catalyst material, wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm; and (ii) contacting the product of step (i) with a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm; and (iii) contacting the product of step (ii) with a nickel catalyst material at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm. Preferably, the alkali metal doped nickel catalyst material used in step (i) is as described above in accordance with the first aspect of the invention. Preferably, the zeolite catalyst material and / or heteropolyacid material used in step (ii) of the process are as described above in accordance with the first aspect of the invention. Preferably, the nickel catalyst material used in step (iii) of the process is as described above for step (ii) of the process of the second aspect of the invention. Typically, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 120 °C to 250 °C. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 150 °C to 200 °C. Typically, the feedstreams (a) and (b) in step (i) are contacted at a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a pressure of from 8 atm to 15 atm. Preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the feedstreams (a) and (b) in step (i) are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the product of step (i) and zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof are contacted at a temperature of from 120 °C to 250 °C and preferably at a temperature of from 150 °C to 200 °C. Typically, the product of step (i) and zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof are contacted at a pressure of from 5 atm to 25 atm and preferably at a pressure of from 8 atm to 15 atm. Preferably, the product of step (i) and zeolite catalyst material, heteropolyac id catalyst material, or a combination thereof are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the product of step (i) and catalyst system are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the product of step (ii) and nickel catalyst material are contacted at a temperature of from 120 °C to 250 °C and preferably at a temperature of from 150 °C to 200 °C. Typically, the product of step (ii) and nickel catalyst material are contacted at a pressure of from 5 atm to 25 atm and preferably at a pressure of from 8 atm to 15 atm. Preferably, the product of step (ii) and nickel catalyst material are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the product of step (ii) and nickel catalyst material are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the process steps are carried out continuously as a continuous flow process. Typically, the process comprises introducing the feedstream (b) at a flow rate of from 25 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in present in steps (i) and (iii). Typically, the process comprises introducing the feedstream (a) at a flow rate of from 25 pl per minute to 100 pl per minute, per gram of total nickel catalyst material present in steps (i) and (iii). Typically, the feedstreams (a) and (b) are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2.5:1 to 1:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones). In some instances, step (iii) further comprises contacting the product of step (ii) and nickel catalyst material with an additional hydrogen feedstream. In these instances, less hydrogen may be used in step (i) as only enough hydrogen is needed for step (i) of the process since the process further comprises introducing additional hydrogen at a later stage for step (iii). However, preferably, the total amount of hydrogen used in the process (i.e. used in steps (i) and (iii)) is a molar ratio of from 2:1 to 10:1 (total moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably a molar ratio of from 2.5:1 to 5:1: more preferably a molar ratio of from 2.5:1 to 4:1; and most preferably a molar ratio of from 2.6:1 to 3:1. Typically, the feedstream (a) is as further described above in accordance with the first aspect of the invention. The process may further comprise pre-treating the nickel catalyst material used in steps (i) and (ii) as discussed above in the context of the first aspect of the invention. The process of the third aspect of the invention may be carried out in a single reaction vessel. For example, the process may comprise introducing the feedstreams (a) and (b) to a reaction vessel where the feedstreams contact the alkali metal doped nickel catalyst material to provide a first intermediate product stream comprising C3 aliphatic alcohol which then contacts the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to provide a second intermediate product stream comprising a C3 aliphatic olefin which then contacts the nickel catalyst material to provide a product stream comprising propane. The process may then comprise recovering the product stream comprising propane from the reaction vessel. It is preferred that the process of the third aspect of the invention occurs in one reaction vessel so as to provide a "one pot” process thus reducing the capital expenditure of the process and space taken up by components in a chemical plant. However, the process may also be carried out in two or three reaction vessels as discussed below. In some instances, the process of the third aspect of the invention may be carried out in three separate reaction vessels. Such a process may comprise introducing the feedstreams (a) and (b) to a first reaction vessel where the feedstreams contact the alkali metal doped nickel catalyst material to provide a first intermediate product stream comprising C3 aliphatic alcohol. The first intermediate product stream may then be recovered from the first reaction vessel and introduced into a second reaction vessel to contact the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to provide a second intennediate product stream comprising C3 aliphatic olefin. The second intermediate product stream may then be recovered from the second reaction vessel and introduced to a third reaction vessel to contact a nickel catalyst material to form a product stream comprising propane. The product stream may then be recovered from the third reaction vessel. As discussed above, the process may comprise introducing an additional hydrogen feedstream to the third reaction vessel. The process of the third aspect of the invention may also be carried out in two reaction vessels using similar configurations as discussed above. For example, the first reaction vessel may comprise the alkali metal doped nickel catalyst material and the zeolite catalyst material, heteropolyacid material, or a combination thereof and the second reaction vessel may comprise a nickel catalyst material. Alternatively, the first reaction vessel may comprise the alkali metal doped nickel catalyst material and the second reaction vessel may comprise the zeolite catalyst material, heteropolyacid material, or a combination thereof and a nickel catalyst material. The process of the third aspect of the invention may be carried out in any suitable reaction vessel(s). The suitable reaction vessel(s) may comprise the catalyst in any suitable configuration or set-up for effectively carrying out the process of the invention. For example, the reaction vessel may comprise a fixed bed reactor. Alternatively, the reaction vessel may comprise a fluidised bed reactor. Preferably, the process of the third aspect of the invention is carried out in one or more fixed bed reactors. The tenn fixed bed reactor as used herein is also used to encompass multi-tubular type reactors. Where multi-tubular type reactors are used, different tubes of the multi-tubular reactor may comprise the different catalyst bed layers. Other suitable features of the reaction vessel(s) and means for implementing the process of the invention are those typically used in the art for a catalytic process such as the process of the invention. According to a fourth aspect of the invention, there is provided a process for the selective production of biopropane from bio-derived aliphatic C3 alcohols, wherein the process comprises contacting: (a) a feedstream comprising one or more aliphatic C3 alcohols and (b) hydrogen in the presence of a catalyst system; wherein the catalyst system comprises: (i) a nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm. As discussed above, the process of the invention may also comprise using a feedstream comprising one or more C3 aliphatic alcohols. In the process of the fourth aspect of the invention, a one pot process is provided which has associated therewith the advantages discussed above associated with one pot processes. Typically, the feedstreams (a) and (b) are contacted at a temperature of from 120 °C to 250 °C. Preferably, the feedstreams (a) and (b) are contacted at a temperature of from 150 °C to 200 °C. Typically, the feedstreams (a) and (b) are contacted at a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) are contacted at a pressure of from 8 atm to 15 atm. Typically, the feedstreams (a) and (b) are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. Preferably, the feedstreams (a) and (b) are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. The process may further comprise pre-treating the nickel catalyst material as discussed above in the context of the first aspect of the invention. Typically, the process is a continuous flow process. Typically, the feedstream (b) is introduced at concentration of 2 to 5 moles, preferably 2.5 to 4 moles, most preferably 2.6 to 3.0 moles, per mole of feedstream (a). Typically, the feedstream (a) is introduced at a flow rate of from 25 pl per minute to 100 pl per minute, per 2 grams of a total of (i) nickel catalyst material, and (ii) a zeolite catalyst material, heteropolvacid catalyst material, or a combination thereof present. Typically, the feedstreams (a) and (b) are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols). Preferably, the feedstreams (a) and (b) are contacted at a molar ratio of from 2:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols); and more preferably, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 alcohols). In the process of the fourth aspect of the invention, less hydrogen is required as the process does not comprise hydrogenation of a ketone or aldehyde to an alcohol. Typically, the feedstream (a) comprises one or more aliphatic C3 alcohols in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream. Preferably, the feedstream (a) comprises isopropyl alcohol. Preferably, the feedstream (a) comprises isopropyl alcohol in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream. Preferably, the feedstream (a) may be derived from any suitable biological source. Suitable biological sources of C3 aliphatic alcohols will be apparent to those of skill in the art given the benefit of the present disclosure. Preferably, the feedstream (a) is derived from fermentation or bio-generation, such as derived from fermentation of flue gases or bio-generated syngas. In some embodiments, the one or more C3 aliphatic alcohols are produced from fermentation of biological organic material, such as fennentation of cellulosic material. Processes for the fermentation of cellulosic material so as to provide biologically derived C3 alcohols are known in the art. In other embodiments, the one or more C3 aliphatic alcohols are derived from recycled carbon. For example, the one or more C3 aliphatic alcohols may be produced from fermentation of flue gases or bio-generated syngas. Flue gases are the waste product stream of many industrial processes. Flue gases and syngas comprise hydrogen, carbon monoxide and carbon dioxide. These gases can be converted by microorganisms in fennentation processes into C3 aliphatic alcohols. The feedstreani (a) may also comprise water as discussed above in the context of the first aspect of the invention. The water may be present in feedstream (a) in the amounts discussed above in the context of the first aspect of the invention. The presence of water in feedstream (a) has been found to provide the same advantages as discussed above in the context of the first aspect of the invention. The catalyst system may be as discussed above in the context of the first aspect of the invention. However, as discussed above, because the fourth aspect of the invention does not comprise the conversion of ketones / aldehydes to alcohol, it is not essential that the nickel catalyst material is alkali metal doped. Accordingly, the nickel catalyst material may alternatively be as discussed above in the context of step (ii) of the second aspect of the invention or step (iii) of the third aspect of the invention. However, it is preferable that the nickel catalyst material is alkali metal doped in the fourth aspect of the invention as this has still been found to promote propane selectivity and greater conversion of the C3 aliphatic alcohol feedstream. Typically, the catalyst system comprises a catalyst bed layer comprising both (i) the nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. Preferably, the catalyst bed layer comprises a single catalyst bed layer comprising both (i) the nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof. In other instances, the catalyst system comprises a first catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a second catalyst bed layer comprising the nickel catalyst material. In these instances, preferably, at least a portion of the one or more aliphatic C3 alcohols present in the feedstream (a) form one or more aliphatic C3 olefins on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 olefins; and the stream comprising one or more aliphatic C3 olefins subsequently contacts the second catalyst bed layer. Typically, the first catalyst bed layer and second catalyst bed layer are separated by a void or by a separation material. Preferably, the first catalyst bed layer and second catalyst bed layer are separated by a separation material comprising silicon carbide. The process of the fourth aspect of the invention may be carried out in any suitable reaction vessel. The suitable reaction vessel may comprise the catalyst in any suitable configuration or set-up for effectively carrying out the process of the invention. For example, the reaction vessel may comprise a fixed bed reactor. Alternatively, the reaction vessel may comprise a fluidised bed reactor. Preferably, the process of the fourth aspect of the invention is carried out in a fixed bed reactor. The term fixed bed reactor as used herein is also used to encompass multi-tubular type reactors. Multi-tubular type reactors may be used for example where the catalyst system comprises more than one catalyst bed layer. In these instances, different tubes of the multitubular reactor may comprise the different catalyst bed layers. Other suitable features of the reaction vessel(s) and means for implementing the process of the invention are those ty pically used in the art for a catalytic process such as the process of the invention. In some instances, the process of the invention may comprise introducing the (a) a feedstream comprising one or more aliphatic C3 alcohols and (b) hydrogen into a reaction vessel comprising the catalyst system and contacting the feedstreams and catalyst system within the reaction vessel before recovering a product stream from the reaction vessel, where the product stream comprises propane. According to a fifth aspect of the invention, there is provided a process for the selective production of biopropane from bio-derived aliphatic C3 alcohols, wherein the process comprises: (i) contacting a feedstream comprising one or more aliphatic C3 alcohols and a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100°C to 300°C and a pressure of from 2 atm to 30 atm; and (ii) contacting the product of step (i) and hydrogen in the presence of a nickel catalyst material at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm. Preferably, the nickel catalyst material and / or feedstream (a) are as described above in accordance with the fourth aspect of the invention. Preferably, the zeolite catalyst material, heteropolvacid catalyst material, or a combination thereof is as described above in accordance yvith the first aspect of the invention. Typically, the contacting in step (i) is carried out at a temperature of from 120 °C to 250 °C. Preferably, the contacting in step (i) is carried out at a temperature of from 150 °C to 200 °C. Typically, the contacting in step (i) is carried out at a pressure of from 5 atm to 25 atm. Preferably, the contacting in step (i) is carried out at a pressure of from 8 atm to 15 atm. Preferably, the contacting in step (i) is carried out at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the feedstreams in step (i) is carried out at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the product of step (i), nickel catalyst material and hydrogen are contacted at a temperature of from 120 °C to 250 °C and preferably at a temperature of from 150 °C to 200 °C. Typically, the product of step (i), nickel catalyst material and hydrogen are contacted at a pressure of from 5 atm to 25 atm and preferably at a pressure of from 8 atm to 15 atm. Preferably, the product of step (i), nickel catalyst material and hydrogen are contacted at a temperature of from 120 °C to 250 °C and a pressure of from 5 atm to 25 atm. More preferably, the product of step (i), nickel catalyst material and hydrogen are contacted at a temperature of from 150 °C to 200 °C and a pressure of from 8 atm to 15 atm. Typically, the process is carried out continuously a continuous flow process. Typically, the process comprises introducing hydrogen at a flow rate of from 25 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in step (ii). Typically, the process comprises introducing the feedstream at a flow rate of from 25 pl per minute to 100 pl per minute, per gram of a total of zeolite catalyst material and heteropolyacid catalyst material present. Typically, the hydrogen and feedstream (a) are introduced at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols). Preferably, the hydrogen and feedstream (a) are introduced at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 alcohols). In the process of the fifth aspect of the invention, less hydrogen is required as the process does not comprise hydrogenation of a ketone or aldehyde to an alcohol. The process may further comprise pre-treating nickel catalyst material as discussed above in the context of the first aspect of the invention. The process of the fifth aspect of the invention may be carried out in a single reaction vessel. For example, the process may comprise introducing the feedstream comprising C3 aliphatic alcohol and a feedstream comprising hydrogen to a reaction vessel where the feedstreams contact the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to provide an intermediate product stream comprising one or more C3 aliphatic olefins which then contacts the nickel catalyst material to provide a product stream comprising propane. The process may then comprise recovering the product stream comprising propane from the reaction vessel. It is preferred that the process of the fifth aspect of the invention occurs in one reaction vessel so as to provide a "one pot” process thus reducing the capital expenditure of the process and space taken up by components in a chemical plant. However, the process may also be carried out in two reaction vessels as discussed below. In some instances, the process of the fifth aspect of the invention may be carried out in two separate reaction vessels. Such a process may comprise introducing the feedstream comprising C3 aliphatic alcohol to a first reaction vessel where the feedstream contacts the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof to provide an intermediate product stream comprising one or more C3 aliphatic olefins. The intermediate product stream may then be recovered from the first reaction vessel and introduced into a second reaction vessel comprising a nickel catalyst material to contact the nickel catalyst material and provide a product stream comprising propane. The product stream comprising propane may then be recovered from the second reaction vessel. In the instances described above, hydrogen may be introduced directly to the second reaction vessel. Alternatively, hydrogen may be introduced to the first reaction vessel and recovered from the first reaction vessel before being introduced to the second reaction vessel. Optionally, hydrogen can be recovered from the first reaction vessel along with the intermediate product stream. In other words, in some instances, the intermediate product stream may further comprise hydrogen that was introduced to the first reaction vessel. The process of the fifth aspect of the invention may be carried out in any suitable reaction vessel(s). The suitable reaction vessel(s) may comprise the catalyst in any suitable configuration or set-up for effectively carrying out the process of the invention. For example, the reaction vessel may comprise a fixed bed reactor. Alternatively, the reaction vessel may comprise a fluidised bed reactor. Preferably, the process of the fifth aspect of the invention is carried out in one or more fixed bed reactors. Hie tenn fixed bed reactor as used herein is also used to encompass multi-tubular type reactors. Where multi-tubular type reactors are used, different tubes of the multi-tubular reactor may comprise the different catalyst bed layers. Other suitable features of the reaction vessel(s) and means for implementing the process of the invention are those typically used in the art for a catalytic process such as the process of the invention. Various advantages are discussed above associated with certain process steps of the first aspect of the invention. For example, advantages associated with the water content of the feedstream comprising C3 aliphatic aldehydes / ketones; the molar ratio of hydrogen to aldehydes / ketones in the process; alkali metal doping of the nickel catalyst material; and phosphorus doping of the zeolite catalyst materials. It will be understood that these advantages are also provided by the corresponding process steps in the second to fifth aspects of the invention for the hydrodeoxygenation process of the invention. The processes of the first to fifth aspects of the invention provide biopropane with a selectivity of at least 90%; preferably at least 92%; more preferably at least 94%; and most preferably at least 95%. According to a sixth aspect of the invention, there is provided a catalyst system comprising (i) an alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; wherein the catalyst system comprises: (a) a catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; (b) a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; and a second catalyst bed layer comprising both a nickel catalyst material and the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; (c) a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; a second catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a third catalyst bed layer comprising a nickel catalyst material; or (d) a first catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a second catalyst bed layer comprising the alkali metal doped nickel catalyst material. Preferably, the catalyst system is as described above in accordance with the first aspect of the invention. According to a seventh aspect of the invention, there is provided the use of a catalyst system according to the sixth aspect of the invention to produce biopropane from one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, one or more aliphatic C3 alcohols, or a combination thereof; wherein the use comprises producing the biopropane with a selectivity of at least 90% and preferably at least 95%. Preferably, the use comprises the use of the catalyst system in a process according to the first, second, third, fourth or fifth aspects of the invention. Various definitions for terms are given above in the context of the first aspect of the invention. It will be understood that these definitions also apply to the terms when used in the context of the second to seventh aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows acetone and hydrogen conversion for a process of the invention with an acetone and 5% water feedstream. Figure 2 shows propane selectivity for a process of the invention with an acetone and 5% water feedstream. Figure 3 shows acetone and hydrogen conversion for a process of the invention with an acetone feedstream comprising 1%, 3% and 5% water. Figure 4 shows propane selectivity for a process of the invention with an acetone feedstream comprising 1%, 3% and 5% water. Figure 5 shows acetone and hydrogen conversion for a process of the invention with an acetone and 5% water feedstream. Figure 6 shows propane selectivity for a process of the invention with an acetone and 5% water feedstream. Figure 7 shows acetone and hydrogen conversion for a reference process with an acetone feedstream comprising 1%, 3% and 5% water. Figure 8 shows propane selectivity for a reference process with an acetone feedstream comprising 1%, 3% and 5% water. Figure 9 shows acetone and hydrogen conversion for a process of the invention with an isopropanol and 1%, 3% or 5% water feedstream. Figure 10 shows propane selectivity for a process of the invention with an isopropanol and 1%, 3% or 5% water feedstream. DETAILED DESCRIPTION OF THE INVENTION Example 1 An alkali metal doped nickel catalyst for use in the process of the invention was prepared by sodium doping the catalyst HTC Ni 500 from Johnson Matthey Catalysts that comprises nickel oxide on an alumina support. The catalyst was doped so as to comprise 5% sodium by weight of the nickel catalyst material. 4.75 g of crushed JM HTC 500 was added to 0.57 g of sodium carbonate dissolved in 2.5 mL of deionised water. The mixture was treated with ultrasound for 30 minutes to ensure complete dissolution. The sodium carbonate was added dropwise to the HTC 500 solid with mechanical mixing with a final 0.5 mL of deionised water added to reach the incipient wetness point of the catalyst. The mixture was mixed thoroughly before being dried at room temperature in a fume cupboard overnight. The dried catalyst material was subjected to further drying in a muffle furnace at 120 °C for twelve hours followed by calcination at 350 °C for four hours. The nickel catalyst was used alongside a 1 wt%phosphorus doped ZSM-5 catalyst with a Si:Al ratio of 80 (preparable according to the disclosure of WO2022 / 122969). A catalyst bed was prepared comprising a top first layer of 0.62 grams of the sodium doped Ni HTC 500 catalyst and a lower layer of 0.62 g of the sodium doped Ni HTC 500 catalyst mixed with 1.25 grams of the P-ZSM-5 catalyst. A silicon carbide layer was used to separate the two catalyst layers. The catalyst bed was arranged in a fixed bed reactor and flushed with argon to remove air. Tire catalyst was then pre-treated with hydrogen at 230 °C for three hours with a hydrogen flow rate of 20 Nml / min. The hydrogen was then switched to argon and the temperature increased to 350 °C and held for one hour before returning to room temperature. The reactor pressure was set at 10 bar and reactor temperature at 180 °C. An acetone feed comprising 5% water was then introduced to the reactor along with a hydrogen feed. The molar ratio of hydrogen to acetone was 2.8:1. The flow rate of the acetone feed was 0.05 mL / min and the flow rate of the hydrogen feed was 45 mL / min. The molar flow rate of the acetone feed was 0.04 moles of acetone per hour. The molar flow rate of hydrogen was 0.112 moles of hydrogen per hour. The results of the experiment are shown in Figures 1 and 2. As shown in Figure 1, acetone conversion was 100% whereas hydrogen conversion was at 60% to 62% over 143 hours. After 143 hours, acetone conversion dropped to 98% to 99% and remained at this level for the remainder of the experiment duration. As shown in Figure 2, propane selectivity was in the range of 95% to 98% over the first 143 hours before dropping marginally for the remainder of the duration of the experiment. The results of Example 1 demonstrate that the process of the invention provides excellent acetone conversion and propane selectivity over a long duration. Example 2 A Nickel catalyst Ni 3354 ERS (0.62 g) that is commercially available from BASF was mixed in a lower catalyst bed layer with a 1% phosphorus promoted ZSM-5 catalyst (preparable according to the disclosure of WO2022 / 122969) (1.25 g). An upper catalyst bed layer comprising only nickel catalyst Ni 3354 ERS (0.62 g) was placed on top with a layer of silicon carbide separating the two catalyst bed layers. The catalyst beds were placed in a fixed bed reactor. The catalyst was pre-reduced in hydrogen at 230 °C for 3 hours. The gas stream was then switched to argon and the temperature increased to 350 °C and held for one hour before returning to room temperature. The reactor pressure was set at 10 bar and reactor temperature at 180 °C. An acetone feed comprising 1% water was then introduced to the reactor along with a hydrogen feed. The molar ratio of hydrogen to acetone was 2.8:1. The flow rate of the acetone feed was 0.05 mL / min and the flow rate of the hydrogen feed was 45 mL / min. The molar flow rate of the acetone feed was 0.04 moles of acetone per hour. The molar flow rate of hydrogen was 0.112 moles of hydrogen per hour. The results of the experiment are shown in Figure 3 and Figure 4. Acetone and hydrogen conversions were maintained at 100% and 62% for the first 65 hours of the reaction. Propane selectivity was around 95% over this period. Acetone conversion began to decrease gradually after 65 hours on-line, levelling off at around 92% to 94% at 85 hours on-line and continuing at a similar degree of conversion until 125 hours of the reaction. Propane selectivity remained around 95%. At 125 hours on-line, the feed was changed to 3% water in acetone. Surprisingly, acetone conversion increased to 95%. At 145 hours on-line, the feed was then changed to 5% water. The acetone conversion remained at 95%. Propane selectivity also remained at around 95%. This demonstrates that increasing the amount of water in the acetone feed has a beneficial effect on acetone conversion in the process of the invention. Example 3 A Nickel catalyst Ni 3354 ERS (0.62 g) that is commercially available from BASF was mixed in a lower catalyst bed layer with a 1% phosphorus promoted ZSM-5 catalyst (preparable according to the disclosure of WO2022 / 122969) (1.25 g). An upper catalyst bed layer comprising only nickel catalyst Ni 3354 ERS (0.62 g) was placed on top with a layer of silicon carbide separating the two catalyst bed layers. The catalyst Ni 3354 ERS is a sodium doped nickel catalyst material. The catalyst beds were placed in a fixed bed reactor. The catalyst was pre-reduced in hydrogen at 230 °C for 3 hours. The gas stream was then switched to argon and the temperature increased to 350 °C and held for one hour before returning to room temperature. The reactor pressure was set at 10 bar and reactor temperature at 180 °C. An acetone feed comprising 1% water was then introduced to the reactor along with a hydrogen feed. The molar ratio of hydrogen to acetone was 2.8:1. The flow rate of the acetone feed was 0.05 mL / min and the flow rate of the hydrogen feed was 45 mL / min. The molar flow rate of the acetone feed was 0.04 moles of acetone per hour. The molar flow rate of hydrogen was 0.112 moles of hydrogen per hour. The results of the experiment are shown in Figure 5 and Figure 6. Acetone and hydrogen conversions were maintained at 100% and 60% to 62% respectively for the duration of the 173 hours on-line as shown in Figure 5. Propane selectivity was around 98% over the same period of time as shown in Figure 6. No changes in conversion or significant changes in selectivity were observed over the course of the experiment. The results in Example 3 show that where the acetone feedstream comprises 5% water from the outset, high levels of acetone conversion are achieved and maintained for the duration of the experiment. Even higher propane selectivity is also achieved and maintained for the duration of the experiment. Example 4 Example 4 is a reference example. In this example, the nickel catalyst HTC Ni 500 was used. However, the catalyst was not doped with alkali metal. HTC Ni 500 was used alongside a 1 wt% phosphorus doped ZSM-5 catalyst with a Si: Al ratio of 80 (preparable according to the disclosure ofWO2022 / 122969). A catalyst bed was prepared comprising a top first layer of 0.63 grams of the Ni HTC 500 catalyst and a lower layer of 0.62 g of the Ni HTC 500 catalyst mixed with 1.25 grams of the P-ZSM-5 catalyst. A silicon carbide layer was used to separate the two catalyst layers. The catalyst bed was arranged in a fixed bed reactor and flushed with argon to remove air. The catalyst was then pre-treated with hydrogen at 230 °C for three hours with a hydrogen flow rate of 20 Nml / min. The hydrogen was then switched to argon and the temperature increased to 350 °C and held for one hour before returning to room temperature. The reactor pressure was set at 10 bar and reactor temperature at 180 °C. An acetone feed comprising 1% water was then introduced to the reactor along with a hydrogen feed. The molar ratio of hydrogen to acetone was 2.8:1. The flow rate of the acetone feed was 0.05 mL / min and the flow rate of the hydrogen feed was 45 mL / min. The molar flow rate of the acetone feed was 0.04 moles of acetone per hour. The molar flow rate of hydrogen was 0.112 moles of hydrogen per hour. The results of the experiment are shown in Figure 7 and Figure 8. Over the first 119 hours on-line the acetone and hydrogen conversions were 100% and around 63% respectively (see Figure 7). Propane selectivity was about 90% to 92% over the same period of time (see Figure 8). The acetone conversion started to drop below 100% after 119 hours on-line. At 121 hours, the pressure was increased to 15 bar which made little difference to either acetone or hydrogen conversions. Product selectivity remained virtually unchanged. The pressure was returned to 10 bar after 146 hours. The rate of deactivation increased and propane selectivity started to drop below 90%. At 169 hours the feed was changed to 3% water in acetone. This had a positive effect as both acetone conversion and selectivity to propane increased. The feed was then changed to 5% water in acetone at 193 hours on-line. The effect of this was very negative with sharp declines in acetone / hydrogen conversions and propane selectivity. The results of Example 4 can be compared to the results of examples 1 to 3. When comparing the results of Example 1 and Example 4. it can be seen that when a sodium doped nickel catalyst is used (as in Example 1), excellent propane selectivity is achieved at 5% water concentration. This is in contrast to where the same nickel catalyst (albeit without sodium doping) is used in Example 4 where 5% water in the feedstream was found to lead to significantly reduced acetone conversion and propane selectivity. Comparing the results of Example 4 and Example 2 shows that at both 1% and 3% water concentration in the acetone feedstream, acetone conversion and propane selectivity were higher for the sodium doped catalyst of Example 2. Where 5% water was included in the acetone feedstream, for the sodium doped catalyst of Example 2, high levels of acetone conversion and propane selectivity were maintained. In clear contrast, where the nickel catalyst was not sodium doped, propane selectivity and acetone conversion dropped significantly. Example 5 Example 5 is included to demonstrate the utility of the process of the invention with a C3 aliphatic alcohol feedstream. HTC Ni 500 was used alongside a 1 wt% phosphorus doped ZSM-5 catalyst with a Si:Al ratio of 80 (preparable according to the disclosure of WO2022 / 122969). A single catalyst bed was prepared comprising 0.63 grams of the Ni HTC 500 catalyst and 1.25 grams of the P-ZSM-5 catalyst. The catalyst bed was arranged in a fixed bed reactor and flushed with argon to remove air. Hie catalyst was then pre-treated with hydrogen at 230 °C for three hours with a hydrogen flow rate of 20 Nml / min. The hydrogen was then switched to argon and the temperature increased to 350 °C and held for one hour before returning to room temperature. The reactor pressure was set at 10 bar and reactor temperature at 180 °C. An isopropanol feed comprising 1 % water was then introduced to the reactor along with a hydrogen feed. The molar ratio of hydrogen to isopropanol was 2.8:1. The flow rate of the acetone feed was 0.05 mL / min and the flow rate of the hydrogen feed was 45 mL / min. The molar flow rate of the acetone feed was 0.04 moles of acetone per hour. The molar flow rate of hydrogen was 0.112 moles of hydrogen per hour. The results of the experiment are shown in Figure 9 and Figure 10. Isopropanol and hydrogen conversions were maintained at 100% and 29% to 32% respectively for the duration of the 170 hour experiment, even after the water concentration had been increased to 3% and then to 5% (see Figure 9). Propane selectivity averaged around 95% over the course of the run (see Figure 10). The results demonstrate that using the process of the invention, very high propane selectivity can be achieved using an isopropanol feed. As discussed above, it was found that sodium doping of the nickel catalyst was not necessary where feedstream comprises a C3 aliphatic alcohol, in contrast to where the feed stream comprises a C3 aliphatic ketone or aldehyde.

Claims

1. A process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises contacting:(a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of a catalyst system comprising: (i) an alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof: andwherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm.

2. A process according to Claim 1. wherein the feedstreams (a) and (b) are contacted at a temperature of from 120 °C to 250 °C.

3. A process according to Claim 1 or Claim 2, wherein the feedstreams (a) and (b) are contacted at a temperature of from 150 °C to 200 °C.

4. A process according to any preceding claim, wherein the feedstreams (a) and (b) are contacted at a pressure of from 5 atm to 25 atm.

5. A process according to any preceding claim, wherein the feedstreams (a) and (b) are contacted at a pressure of from 8 atm to 15 atm.

6. A process according to any preceding claim, wherein the process is a continuous flow process.

7. A process according to Claim 6, wherein the feedstream (b) is introduced at a concentration of 2 to 5 moles, preferably 2.5 to 4 moles, most preferably 2.6 to 3.0 moles, per mole of feedstream (a).

8. A process according to Claim 6 or Claim 7, wherein the feedstream (a) comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof is introduced at a flow rate of from 25 pl per minute to 100 pl per minute, per 2 grams of a total of (i) alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof present.

9. A process according to any preceding claim, wherein the catalyst system is pre-treated with hydrogen to reduce the alkali metal doped nickel catalyst material.

10. A process according to Claim 9, wherein the catalyst system is pre-treated at a temperature of from 150 °C to 300 °C. preferably from 200 °C to 250 °C, for a time period of from 1 hour to 5 hours.

11. A process according to Claim 9 or Claim 10, wherein the pre-treatment further comprises contacting the catalyst system with an inert gas at a temperature of from 250 °C to 400 °C for a time period of greater than 30 minutes; preferably wherein the inert gas comprises argon.

12. A process according to any preceding claim, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones), preferably at a molar ratio of from 2.5:1 to 5:1; more preferably at a molar ratio of from 2.5:1 to 4:1; and most preferably at a molar ratio of from 2.6:1 to 3:1.

13. A process according to any preceding claim, wherein the feedstream (a) is derived from fermentation or bio-generation, such as derived from fermentation of flue gases or biogenerated syngas.

14. A process according to any preceding claim, wherein the feedstream (a) comprises one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream.

15. A process according to any preceding claim, wherein the feedstream (a) comprises acetone.

16. A process according to any preceding claim, wherein the feedstream (a) further comprises water.

17. A process according to Claim 16, wherein the water is present in an amount of up to 20% by weight of the total weight of components of the feedstream: preferably in an amount of up to 10% by weight of the total weight of components of the feedstream; more preferably in an amount of up to 5% by weight of the total weight of components of the feedstream; and most preferably in an amount of up to 3% by weight of the total weight of components of the feedstream.

18. A process according to Claim 17, wherein the water is present in an amount of from 0.5% to 20% by weight of the total weight of components of the feedstream; preferably 1% to 10% by weight of the total weight of components of the feedstream; more preferably from 3% to 10% by weight of the total weight of components of the feedstream; and most preferably from 3% to 5% by weight of the total weight of components of the feedstream.

19. A process according to any preceding claim, wherein the heteropolyacid catalyst material comprises a tungstophosphoric acid; preferably wherein the tungstophosphoric acid comprises 12-tungstophosphoric acid (HPW).

20. A process according to any preceding claim, wherein the one or more zeolite catalyst materials comprises one or more ZSM5 zeolite materials, one or more Zeolite Y materials, one or more MCM zeolite materials, one or more SSZ-13 zeolite materials, or a combination thereof.

21. A process according to any preceding claim, wherein the one or more zeolite catalyst materials comprises a boron and / or phosphorus promoted ZSM5 zeolite material; preferably a phosphorus promoted Zeolite Y material, a phosphorus promoted MCM zeolite material, a phosphorus promoted SSZ-13 zeolite material, or a combination thereof.

22. A process according to Claim 21, wherein the phosphorus promoted ZSM5 zeolite material, phosphorus promoted Zeolite Y material, phosphorus promoted MCM zeolite material, or phosphorus promoted SSZ-13 zeolite material comprises from 0.1% to 5% by weight phosphorus: and preferably from 0.5% to 3% by weight phosphorus.

23. A process according to any one or more of Claims 20 to 22, wherein the one or more ZSM5 zeolite materials or the one or more Zeolite Y materials has a Si / Al ratio of from 2 to 500; preferably from 5 to 400; more preferably from 20 to 150; still more preferably from 50 to 100; and most preferably from 70 to 90.

24. A process according to any preceding claim, wherein the catalyst system comprises one or more zeolite catalyst materials comprising a boron and / or phosphorus promoted ZSM5 zeolite material, or a boron and / or phosphorus promoted Zeolite Y material; preferably wherein the phosphorus promoted ZSM5 zeolite material or phosphorus promoted Zeolite Y material comprises from 0.5% to 3% by weight phosphorus and has a Si / Al ratio of from 50 to 100.

25. A process according to any preceding claim, wherein the alkali metal doped nickel catalyst material comprises from 0.5% to 20% by weight of a total of the one or more alkali metals; preferably wherein the alkali metal doped nickel catalyst material comprises from 1% to 10% by weight of a total of the one or more alkali metals; and more preferably, wherein the alkali metal doped nickel catalyst material comprises from 2% to 8% by weight of a total of the one or more alkali metals.

26. A process according to any preceding claim, wherein the alkali metal doped nickel catalyst material comprises one or more of lithium, sodium, potassium, rubidium, caesium, or a combination thereof; preferably wherein the alkali metal doped nickel catalyst material comprises one or more of lithium, sodium, potassium, or a combination thereof.

27. A process according to any preceding claim, wherein the alkali metal doped nickel catalyst material comprises sodium in an amount of from 0.5% to 20% by weight; preferably from 1% to 10% by weight; and more preferably from 2% to 8% by weight.

28. A process according to any preceding claim, wherein the alkali metal doped nickel catalyst material comprises alkali metal doped nickel oxide: and preferably sodium doped nickel oxide.

29. A process according to any preceding claim, wherein the alkali metal doped nickel catalyst material comprises a carrier, binder, or support material; preferably, wherein the alkali metal doped nickel catalyst material comprises an alumina support material.

30. A process according to Claim 29, wherein the alkali metal doped nickel catalyst material comprises a carrier, binder, or support material present in an amount of from 0.1% to 40% by weight of the alkali metal doped nickel catalyst material.

31. A process according to any preceding claim, wherein the catalyst system comprises the (i) alkali metal doped nickel catalyst material and the (ii) zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof in a mass ratio of from 1:1 to 1:5; and preferably from 1:1.5 to 1:3.

32. A process according to any preceding claim, wherein the catalyst system comprises a catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; preferably, wherein the catalyst bed comprises a single catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof.

33. A process according to any preceding claim, wherein the catalyst system comprises: a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; and a second catalyst bed layer comprising both a nickel catalyst material and the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof.

34. A process according to Claim 33, wherein at least a portion of the feedstream (a) fonns one or more aliphatic C3 alcohols on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 alcohols; and wherein the stream comprising one or more aliphatic C3 alcohols subsequently contacts the second catalyst bed layer.

35. A process according to any one or more of Claims 1 to 31, wherein the catalyst system comprises: a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; a second catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a third catalyst bed layer comprising a nickel catalyst material.

36. A process according to Claim 35, wherein at least a portion of the feedstream (a) fonns one or more aliphatic C3 alcohols on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 alcohols; and wherein the stream comprising one or more aliphatic C3 alcohols subsequently contacts the second catalyst bed layer to form a stream comprising one or more aliphatic C3 olefins; and wherein the stream comprising one or more aliphatic C3 olefins subsequently contacts the third catalyst bed layer.

37. A process according to any one or more of Claims 33 to 36, wherein the first catalyst bed layer and second catalyst bed layer are separated by a void or by a separation material; preferably wherein the first catalyst bed layer and second catalyst bed layer are separated by a separation material comprising silicon carbide.

38. A process according to any one or more of Claims 33 to 3 7, wherein the second catalyst bed layer and third catalyst bed layer are separated by a void or by a separation material; preferably wherein the second catalyst bed layer and third catalyst bed layer are separated by a separation material comprising silicon carbide.

39. A process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises:(i) contacting (a) a feedstream comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of an alkali metal doped nickel catalyst material, wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm; and(ii) contacting the product of step (i) with a catalyst system comprising (I) a nickel catalyst material, and (II) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm.

40. A process according to Claim 39, wherein the alkali metal doped nickel catalyst material in step (i) is as defined in any one or more of Claims 25 to 30; and / or wherein the catalyst system in step (ii) is as defined in any one or more of Claims 18 to 32.

41. A process according to Claim 39 or Claim 40, wherein the contacting of the feedstreams (a) and (b) is as defined in any one or more of Claims 2 to 5; and / or wherein the product of step (i) and catalyst system are contacted as defined in any one or more of Claims 2 to 5.

42. A process according to any one or more of Claims 39 to 41, wherein the process steps are carried out continuously as a continuous flow process.

43. A process according to Claim 42, wherein the process comprises introducing the feedstream (b) at a flow rate of from 25 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in steps (i) and (ii); and / or wherein the process comprises introducing the feedstream (a) at a flow rate of from 25 pl per minute to 100 pl per minute, per gram of total nickel catalyst material present in steps (i) and (ii).

44. A process according to any one or more of Claims 39 to 43, wherein the feedstreams (a) and (b) in step i), are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably, wherein the feedstreams (a) and (b) in step (i) are contacted at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones).

45. A process according to any one or more of Claims 39 to 44, wherein the feedstream (a) is as further defined in any one or more of Claims 13 to 18.

46. A process according to any one or more of Claims 39 to 45, wherein step (ii) further comprises contacting the product of step (i) and catalyst system with an additional hydrogen feedstream.

47. A process for the selective production of biopropane from bio-derived aliphatic C3 ketones, aliphatic C3 aldehydes, or a combination thereof, wherein the process comprises:(i) contacting (a) a feedstreani comprising one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, or a combination thereof and (b) hydrogen in the presence of an alkali metal doped nickel catalyst material, wherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm: and(ii) contacting the product of step (i) with a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm: and(iii) contacting the product of step (ii) with a nickel catalyst material at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm.

48. A process according to Claim 47, wherein the nickel catalyst material in steps (i) and / or (iii) is as defined in any one or more of Claims 25 to 30; and / or wherein the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof is as defined in any one or more of Claims 19 to 24.

49. A process according to Claim 47 or Claim 48, wherein the contacting of the feedstreams (a) and (b) is as defined in any one or more of Claims 2 to 5: the contacting of the product of step (i) with the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof is as defined in any one or more of Claims 2 to 5; and / or the contacting of the product of step (ii) with the nickel catalyst material is as defined in any one or more of Claims 2 to 5.

50. A process according to any one or more of Claims 47 to 49, wherein the process steps are carried out continuously as a continuous flow process.

51. A process according to Claim 50, wherein the process comprises introducing the feedstream (b) at a flow rate of from 50 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in present in steps (i) and (iii); and / or wherein the process comprises introducing the feedstream (a) at a flow rate of from 50 pl per minute to 100 pl per minute, per gram of total nickel catalyst material present in steps (i) and (in)52. A process according to any one or more of Claims 47 to 51, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones); preferably, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2.5:1 to 1:1 (moles of hydrogen: total moles of aliphatic C3 aldehydes and aliphatic C3 ketones).

53. A process according to any one or more of Claims 47 to 52, wherein the feedstream (a) is as further defined in any one or more of Claims 13 to 18.

54. A process according to any one or more of Claims 47 to 53, wherein step (iii) further comprises contacting the product of step (ii) and nickel catalyst material with an additional hydrogen feedstream.

55. A process for the selective production of biopropane from bio-derived aliphatic C3 alcohols, wherein the process comprises contacting:(a) a feedstream comprising one or more aliphatic C3 alcohols and (b) hydrogen in the presence of a catalyst system; wherein the catalyst system comprises: (i) a nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; andwherein the feedstreams (a) and (b) are contacted at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm.

56. A process according to Claim 55, wherein the process is as further defined in any one or more of Claims 2 to 6 and 9 to 11.

57. A process according to Claim 56, wherein the feedstream (b) is introduced at concentration of 2 to 5 moles, preferably 2.5 to 4 moles, most preferably 2.6 to 3.0 moles, per mole of feedstream (a).

58. A process according to Claim 56 or Claim 57, wherein the feedstream (a) is introduced at a flow rate of from 25 pl per minute to 100 pl per minute, per 2 grams of a total of (i) nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof present.

59. A process according to any one or more of Claims 56 to 58, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols); preferably, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols): and more preferably, wherein the feedstreams (a) and (b) are contacted at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 alcohols).

60. A process according to any one or more of Claims 56 to 59, wherein the feedstream (a) comprises one or more aliphatic C3 alcohols in an amount of 70% or more by weight, preferably 80% or more by weight, and more preferably 90% or more by weight of the total weight of components of the feedstream.

61. A process according to any one or more of Claims 56 to 60, wherein the feedstream (a) comprises isopropyl alcohol.

62. A process according to any one or more of Claims 56 to 61, wherein the feedstream (a) is as further defined in any one or more of Claims 13 or 16 to 18.

63. A process according to any one or more of Claims 56 to 62, wherein the catalyst system is as defined in any one or more of Claims 19 to 31.

64. A process according to any one or more of Claims 56 to 63, wherein the catalyst system comprises a catalyst bed layer comprising both (i) the nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; preferably, wherein the catalyst bed comprises a single catalyst bed layer comprising both (i) the nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof.

65. A process according to any one or more of Claims 56 to 64, wherein the catalyst system comprises a first catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a second catalyst bed layer comprising the nickel catalyst material.

66. A process according to Claim 65, wherein at least a portion of the one or more aliphatic C3 alcohols present in the feedstream (a) fonn one or more aliphatic C3 olefins on contact with the first catalyst bed layer thereby providing a stream comprising one or more aliphatic C3 olefins; and wherein the stream comprising one or more aliphatic C3 olefins subsequently contacts the second catalyst bed layer.

67. A process according to any one or more of Claims 56 to 66, wherein the first catalyst bed layer and second catalyst bed layer are separated by a void or by a separation material; preferably wherein the first catalyst bed layer and second catalyst bed layer are separated by a separation material comprising silicon carbide.

68. A process for the selective production of biopropane from bio-derived aliphatic C3 alcohols, wherein the process comprises:(i) contacting a feedstream comprising one or more aliphatic C3 alcohols and a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof at a temperature of from 100°C to 300°C and a pressure of from 2 atm to 30 atm; and(ii) contacting the product of step (i) and hydrogen in the presence of a nickel catalyst material at a temperature of from 100 °C to 300 °C and a pressure of from 2 atm to 30 atm.

69. A process according to Claim 68, wherein the nickel catalyst material is as defined in any one or more of Claims 25 to 30.

70. A process according to Claim 68 or Claim 69, wherein the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof is as defined in any one or more of Claims 19 to 24.

71. A process according to any one or more of Claims 68 to 70, wherein the contacting carried out in steps (i) and / or (ii) is as defined in any one or more of Claims 2 to 5.

72. A process according to any one or more of Claims 68 to 71, wherein the process is carried out continuously as a continuous flow process.

73. A process according to Claim 72, wherein the process comprises introducing hydrogen at a flow rate of from 25 ml of hydrogen per minute to 100 ml of hydrogen per minute, per gram of total nickel catalyst material present in step (ii).

74. A process according to Claim 72 or Claim 73, wherein the process comprises introducing the feedstream at a flow rate of from 25 pl per minute to 100 pl per minute, per gram of a total of zeolite catalyst material and heteropolyacid catalyst material present.

75. A process according to any one or more of Claims 72 to 74, wherein the hydrogen and feedstream (a) are introduced at a molar ratio of from 1:1 to 10:1 (moles of hydrogen: total moles of aliphatic C3 alcohols); preferably, wherein the hydrogen and feedstream (a) are introduced at a molar ratio of from 2.5:1 to 5:1 (moles of hydrogen: total moles of aliphatic C3 alcohols).

76. A process according to any one or more of Claims 68 to 75, wherein the feedstream (a) is as further defined in any one or more of Claims 60 to 62.

77. A process according to any preceding claim, wherein the process provides biopropane with a selectivity of at least 90%: and preferably at least 95%.

78. A catalyst system comprising (i) an alkali metal doped nickel catalyst material, and (ii) a zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; wherein the catalyst system comprises:(a) a catalyst bed layer comprising both (i) the alkali metal doped nickel catalyst material, and (ii) the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof;(b) a first catalyst bed layer comprising the alkali metal doped nickel catalyst material: and a second catalyst bed layer comprising both a nickel catalyst material and the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof;(c) a first catalyst bed layer comprising the alkali metal doped nickel catalyst material; a second catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalystmaterial, or a combination thereof; and a third catalyst bed layer comprising a nickel catalyst material; or(d) a first catalyst bed layer comprising the zeolite catalyst material, heteropolyacid catalyst material, or a combination thereof; and a second catalyst bed layer comprising the alkali metal doped nickel catalyst material.

79. A catalyst system according to Claim 78, wherein the catalyst system is as defined in any one or more of Claims 1, or 20 to 35.

80. Use of a catalyst system according to Claim 78 or Claim 79 to produce biopropane from one or more aliphatic C3 ketones, one or more aliphatic C3 aldehydes, one or more aliphatic C3 alcohols, or a combination thereof; wherein the use comprises producing the biopropane with a selectivity of at least 90% and preferably at least 95%; preferably wherein the use comprises the use of the catalyst system in a process according to any one or more of Claims 1 to 79.Application No: GB2414649.0 Examiner: Dr S. David EvansClaims searched: 1-18, 25-80 (in part), 20-24 (in Date of search: 4 April 2025full)Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance A - CN 110526860 A (NINGXIA VOCARON NEW MAT CO LTD) See WPI Abs. Acc. No. 2019-A2980W and the whole document. A - GB 2602623 A (CALOR GAS LTD) See the entire document, but especially Example 7. A - US 2014 / 171691 Al (KORTAN et al) See the whole document.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and or state of the art. Y Document indicating lack of inventive step if combined with one or more other documents of same category. P Document published on or alter the declared priority date but before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP. WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC____________BOU; C01B; C07C; C10L_________________________________________The following online and other databases have been used in the preparation of this search reportCAS ONLINE, SEARCH PATENT, SEARCH NPLInternational Classification:Subclass Subgroup Valid From C07C 0001 / 207 01 / 01 / 2006 BOU 0023 / 755 01 / 01 / 2006 BOU 0027 / 188 01 / 01 / 2006 B01J 0029 / 40 01 / 01 / 2006 BOU 0029 / 70 01 / 01 / 2006 B01J 0035 / 00 01 / 01 / 2024 C01B 0039 / 38 01 / 01 / 2006 C01B 0039 / 46 01 / 01 / 2006 C07C 0001 / 20 01 / 01 / 2006 C07C 0001 / 22 01 / 01 / 2006 C10L 0003 / 12 01 / 01 / 2006Application No:     GB2414649.0Claims searched: 1-18, 25-80 (in part), 19 (in full)Examiner: Dr S. David EvansDate of search: 2 December 2025Patents Act 1977Further Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance A - CN 105854943 A (UNIV JIANGXI SCI &TECHNOLOGY) See WPI Abs. Acc. No 2016-52604A. A - JP S5746925 A (SHINNENRYOYU KAIHATSU GIJUTSU) See WPI Abs. Acc. No. 1982-33777E. A - US 4757044 A (COOPER et al) See the whole document.Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and or state of the art. Y Document indicating lack of inventive step if combined with one or more other documents of same category . P Document published on or alter the declared priority date but before the filing date of this invention. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB. EP. WO &US patent documents classified in the following areas of the UKCXWorldwide search of patent documents classified in the following areas of the IPC____________BOU; C01B; C07C; C10LThe following online and other databases have been used in the preparation of this search reportSEARCH PATENT, SEARCH NPLInternational Classification:Subclass Subgroup Valid From C07C 0001 / 207 01 / 01 / 2006 BOU 0023 / 755 01 / 01 / 2006 BOU 0027 / 188 01 / 01 / 2006 B01J 0029 / 40 01 / 01 / 2006 BOU 0029 / 70 01 / 01 / 2006Subclass Subgroup Valid From B01J 0035 / 00 01 / 01 / 2024 C01B 0039 / 38 01 / 01 / 2006 C01B 0039 / 46 01 / 01 / 2006 C07C 0001 / 20 01 / 01 / 2006 C07C 0001 / 22 01 / 01 / 2006 C10L 0003 / 12 01 / 01 / 2006

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