WO2024110575A1 - Oligomérisation d'alcools - Google Patents

Oligomérisation d'alcools Download PDF

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Publication number
WO2024110575A1
WO2024110575A1 PCT/EP2023/082825 EP2023082825W WO2024110575A1 WO 2024110575 A1 WO2024110575 A1 WO 2024110575A1 EP 2023082825 W EP2023082825 W EP 2023082825W WO 2024110575 A1 WO2024110575 A1 WO 2024110575A1
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Prior art keywords
ethanol
solvent
reaction
imidazole
benzimidazole
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PCT/EP2023/082825
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English (en)
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Kapil Shyam Lokare
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Terra Mater BV
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Publication of WO2024110575A1 publication Critical patent/WO2024110575A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/32—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions without formation of -OH groups
    • C07C29/34—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions without formation of -OH groups by condensation involving hydroxy groups or the mineral ester groups derived therefrom, e.g. Guerbet reaction

Definitions

  • the invention relates to the technical field of catalytic oligomerisation of lower alcohols to higher alcohols, and the oligomerisation ethanol to n-butanol in particular.
  • n-butanol A way to synthesise n-butanol is to use ethanol as a starting molecule and use a catalysed reaction process.
  • Two catalysed reaction mechanisms are proposed in literature: the direct dimerisation of two molecules of ethanol, and a multi-step tandem synthetic route known as the Guerbet reaction.
  • the prerequisite for the “direct mechanism” is a high reaction temperature (> 350°C), while the indirect route is the reaction mechanism at lower reaction temperatures.
  • the search for homogeneous and heterogeneous catalysts has recently received great attention in both the scientific and industrial field.
  • the main types of homogeneous catalysts for upgrading ethanol to n-butanol are complexes of iridium, manganese, gold, copper, niobium, platinum, palladium, vanadium, titanium, zirconium, iron, ruthenium, molybdenum, osmium, or nickel; in combination with a strong base, e.g., sodium hydroxide, potassium hydroxide, or sodium ethoxide. These reactions are believed to proceed via a Guerbet reaction mechanism.
  • the transition metals are responsible for the dehydrogenation of the ethanol and for the aldehyde hydrogenation, while the strong base is responsible for the aldol condensation.
  • heterogeneous catalysts In view of the drawbacks of homogeneous catalysts, heterogeneous catalysts, processes, and corresponding reaction mechanisms have been extensively explored as a solution for the conversion of ethanol to n-butanol in recent years.
  • These heterogeneous catalysts include metal oxides, zeolites, hydroxyapatite catalysts, mixed metal oxides, and supported metal catalysts.
  • all reported types of heterogeneous catalysts each come with their own shortcomings. These are: low selectivity for n-butanol, low conversation rates, and harsh reaction conditions. Other problems these catalysts can suffer from are poor water tolerance and a high cost. Adequate tolerance to water is very important, since water is typically present in the reactant mixture and water is generated in the dehydration reaction of the reaction process.
  • n-butanol is industrially synthesised directly from petroleum feedstock via an energy-intensive process, or via the time-consuming fermentation process of which the yield is very low as summarised above.
  • An alternative process is the synthesis of n-butanol from bio-ethanol via a wide variety of catalysts. This has been extensively researched and documented in both scientific papers and patents.
  • limiting factors in the industrialisation of the catalysed bio-ethanol/n-butanol conversion with the catalyst synthesised up till now include: low selectivity for n-butanol, low conversion rates, harsh reaction conditions (high temperatures and/or high pressures), poor water tolerance of the catalyst(s), catalyst cost, and lack of scalability.
  • the above explains why it is currently not economical to produce n-butanol from ethanol via a catalytic reaction.
  • WO 2015/031561 A1 discloses methods of converting a lower alcohol (e.g., ethanol) to a higher alcohol (e.g., butanol) in the presence of a water stable transition metal catalyst comprising a Group VIII transition metal and a polydentate nitrogen donor ligand.
  • WO 2019/193079 A1 discloses a process for obtaining higher aliphatic alcohols starting from aliphatic primary alcohols by condensation reactions. Specifically, the process comprises a step in which an aliphatic primary alcohol is contacted in a homogeneous phase with a catalyst mixture comprising a transition metal, a base and an additive.
  • the present invention offers conversion of Ci, C2, C3 and, C5 alcohols that are derived from renewable feedstocks to higher (C4+) alcohols with can be further upgraded using known industrial processes.
  • An advantage of the present invention is that this type of catalyst is air stable and water stable. Therefore, the reaction mixture can easily be prepared in air.
  • a further advantage of the present invention is that a very high conversion rate of ethanol can be achieved.
  • a further advantage of the present invention is that little to no side products are formed, such as acetaldehyde, crotonaldehyde, or any other aldol condensation products.
  • a further advantage of the present invention is that no additional hydrogen feed is required.
  • a further advantage of the present invention is that the product can be controlled by the reaction time, for example, longer reaction times afford higher alcohols as Ce and Cs homologues.
  • a further advantage of the present invention is that it offers an economically viable ethanol oligomerisation by providing an efficient combination of both a high-selectivity reaction step to n-butanol combined with an efficient catalyst recycling to keep catalyst leaching at its lowest.
  • a further advantage of the present invention is that the application of specific solvent systems allows for optimal reaction conditions as well as optimal catalyst-recycling conditions.
  • a further advantage of the present invention is the use of just water which can be purified by simple molecular sieve distillation. Additional impurities such as fusel alcohols from fermentation process do not hinder the present process.
  • a further advantage of the present invention is that the complexities of the processes of the prior art are avoided.
  • a further advantage of the present invention is that no specific control of partial pressures is necessary as no syngas feed or hydrogen input is required.
  • a further advantage of the present invention is that no n-selectivity requirements exist. With the current invention only n-butanol is obtained.
  • a further advantage of the present invention is that mixtures may be prepared in air and have a catalyst stability of few months under ambient conditions, and no complex set ups such as those in the prior art are required.
  • a further advantage of the present invention is that a relatively clean single product is obtained that is simpler and leads to an overall simpler process.
  • a further advantage of the present invention is that in the process, C4, Ce and Cs alcohols are obtained whilst C4 product is predominant, larger conversions to Ce and Cs are formed upon prolonged heating.
  • a further advantage of the present invention is that it may start from bio-ethanol that is green and also operates under 200 °C making it quite simple and commercially attractive.
  • a further advantage of the present invention is that the process is not limited to alumina production co-location sites or pyrophoric catalysts.
  • a further advantage of the present invention is that the process takes about 6h in comparison to ABE fermentation and therefore provides a higher turnover.
  • a further advantage of the present invention is that co-location can be beneficial but is not a necessity to the success of the economics.
  • a further advantage of the present invention is that the conversion and selectivity to n-butanol are high enough to exclude dependence on side streams for profitability.
  • the present invention allows to use existing infrastructure from fossil based commercial plants and can be retrofitted.
  • the present invention relates to a process for converting a C1.3 alcohol to higher alcohols.
  • the process preferably comprises the steps of: a. pre-mixing a C1.3 alcohol, a catalyst, and a multicomponent solvent system, to form a liquid mixture; and b. heating the liquid mixture, thereby obtaining higher alcohols.
  • the multicomponent solvent system preferably comprises at least a basic aqueous hydrocarbon solvent phase comprising at least two different hydrocarbons; wherein the solvent comprises a base selected from the group comprising: potassium hydroxide, sodium hydroxide, potassium ethoxide, sodium ethoxide, potassium t-butoxide, sodium t-butoxide, or combinations thereof, for example a eutectic mixture of sodium and potassium hydroxide.
  • the catalyst comprises an (HL)M(OH) n (H2O) m type complex and preferably comprises activated carbon.
  • M is a metal, preferably selected from the group comprising: Ru, Co, Ir, Rh, Os, Mo, W, Sc, Tc, Pt, Pd, Fe, or Ni.
  • HL is a protic mono-, di-, or a polydentate organic ligand, preferably selected from the group comprising: indole, maleimide, maltol, 5-hydroxymaltol, kojic acid, tropolone, thujaplicin, hinokitiol, stipitatic acid, 2,6-bis[4-isopropyl-2-oxazolin-2-yl]pyridine, imidazole, 2,6-bis[4-phenyl-2-oxazolin-2-yl]pyridine, 2,6-bis[(3,8)-8H-indeno[1 ,2- d]oxazolin-2-yl)pyridine, pyrrole, pyrazole, 4-hydroxypyrazole, pyrazole-3- carboxyladehyde, pyrazole-3-carboxylic acid, pyrazole-4-carboxylic acid, pyrazole-
  • the C1.3 alcohol is ethanol, preferably bio-ethanol. In some preferred embodiments, the solvent/ethanol ratio is at least 2.0, preferably at least 3.0. In some preferred embodiments, the ethanol is fuel grade ethanol.
  • the ligand HL is selected from the group comprising: imidazole, 4-hydroxybenzimidazole, 1 -benzylimidazole, 2-methylbenzimidazole, 2- phenylimidazole, 2-alkylimidazole, 2-arylimidazole, 4-alkylimidazole, 2-aminobenzimidazole, 2-alkylbenzimidazole, 4,5-diarylimidazole, 4,5-dialkylimidazole, 2,4,5-triarylimidazole, 2,4,5- trialkylimidazole, 4-arylimidazole, 5-alkylimidazole, 5-arylimidazole, 4-methylimidazole, 4- arylimidazole, 5-alkylimidazole, 5-arylimidazole, 5-methylimidazole, 2-(1 H-imidazol-2- yl)pyridine, 2-(1-hydroxyethyl)benzimidazole, 5-methylimidazole, 2-
  • the catalyst further comprises a skeletal or metal sponge catalyst; preferably Raney nickel.
  • the basic aqueous solvent phase comprises an alkali hydroxide; preferably KOH.
  • step a. is performed at ambient temperature.
  • step b. comprises one or more, preferably all, of the steps of: b1 . heating the mixture to a temperature T1 in a time frame At1 ; b2. heating the mixture to a temperature T2 in a time frame At2; and, b3. maintaining the mixture at the temperature T2 during a time frame At3.
  • T2 is from at least 140°C to at most 500°C, preferably from at least 150°C to at most 400°C, preferably from at least 160°C to at most 300°C, preferably from at least 170°C to at most 260°C, preferably from at least 180°C to at most 240°C, preferably from at least 190°C to at most 220°C, preferably about 200°C.
  • the C1.3 alcohol is converted to n-butanol. In some preferred embodiments, the C1.3 alcohol is converted to Ce-s alcohols.
  • the reaction vessel acts as an intrinsic catalyst.
  • the process further comprises the step of: a. distilling the higher alcohols.
  • the present invention relates to use of a catalyst as described herein, in the conversion of a C1.3 alcohol to higher alcohols
  • FIG. 1 illustrates multiple cascade reactions for the production of oxo-alcohols (underlined) from crude oil.
  • FIG. 2 illustrates proposed cascade reactions for the formation of n-butanol (underlined), while products from side reactions are not underlined.
  • FIG. 3 illustrates a conceptual diagram showing possible ligand deprotonation by bases.
  • FIG. 4 illustrates a schematic representation of phase separation according to an embodiment of the invention.
  • the lower area is the water phase, while the upper area is the hydrocarbon phase.
  • FIG. 5 illustrates the reaction kinetics according to an embodiment of the invention.
  • FIG. 6 demonstrates the partition coefficient of octanol/water at 25°C of the molecules in the reaction pathway.
  • FIG. 7 illustrates a schematic representation of phase separation for the conversion of 1- propanol.
  • FIG. 8 illustrates a schematic representation of gas chromatograph of the crude phase conversion of ethanol.
  • FIG. 9 illustrates a schematic representation of gas chromatograph of crude phase conversion of ethanol + 1-propanol.
  • a step means one step or more than one step.
  • substituted is meant to indicate that one or more hydrogens on the atom indicated in the expression using “substituted” is replaced with a selection from the indicated group, provided that the indicated atom’s normal valency is not exceeded, and that the substitution results in a chemically stable compound, /.e., a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture.
  • the present invention relates to a process for converting a C1.3 alcohol to higher alcohols.
  • the process preferably comprises the steps of: a. pre-mixing a C1.3 alcohol, a catalyst, and a multicomponent solvent system, to form a liquid mixture; and b. heating the liquid mixture, thereby obtaining higher alcohols.
  • the catalyst comprises an (HL)M(OH) n (H2O) m type complex, wherein m and n each independently represent an integer, for example of 1 , 2, or 3, and preferably also comprises activated carbon.
  • M is a metal, preferably selected from the group comprising: Ru, Co, Ir, Rh, Os, Mo, W, Sc, Tc, Pt, Pd, Fe, or Ni.
  • the metal is Ru, Co, Ni or V.
  • the metal is Ru or Co.
  • the metal is Ru.
  • ligand (HL) FIG. 3 was found to be important in the present invention, since addition of a strong base such as KOH to any transition metal halide may result in the formation of insoluble, inactive, black precipitates - presumably oxides.
  • steps involved in the current invention are thermal operations such as transformation of ethanol to n-butanol, distillation, rectification, /.e., processes that normally would lead to thermal stresses on the catalyst which can cause decomposition reactions and progressive deactivation during the lifetime of the catalyst. Thermal separation processes seldom give quantitative recovery of the catalyst, which causes loss of productivity through loss of metal.
  • the ligand provides a high polarity of the catalyst and consequent insolubility in the organic phase providing a minimum loss of metal.
  • HL is a protic mono-, di-, or a polydentate organic ligand, preferably selected from the group comprising: indole, maleimide, maltol, 5-hydroxymaltol, kojic acid, tropolone, thujaplicin, hinokitiol, stipitatic acid, 2,6-bis[4-isopropyl-2-oxazolin-2- yl]pyridine, imidazole, 2,6-bis[4-phenyl-2-oxazolin-2-yl]pyridine, 2,6-bis[(3,8)-8H-indeno[1 ,2- d]oxazolin-2-yl)pyridine, pyrrole, pyrazole, 4-hydroxypyrazole, pyrazole-3-carboxyladehyde, pyrazole-3-carboxylic acid, pyrazole-4-carboxylic acid, pyrazole-3,5-dicarboxylic acid, 4- alkyl/
  • the ligand HL is selected from the group comprising: indole, maleimide, maltol, 5-hydroxymaltol, kojic acid, tropolone, thujaplicin, hinokitiol, stipitatic acid, 2,6-bis[4-isopropyl-2-oxazolin-2-yl]pyridine, imidazole, 2,6-bis[4-phenyl-2-oxazolin-2- yl]pyridine, 2,6-bis[(3,8)-8H-indeno[1 ,2-d]oxazolin-2-yl)pyridine, pyrrole, pyrazole, 4- hydroxypyrazole, pyrazole-3-carboxyladehyde, pyrazole-3-carboxylic acid, pyrazole-4- carboxylic acid, pyrazole-3,5-dicarboxylic acid, 4-alkyl/aryl pyrazole, 3-alkyl/aryl pyrazole, 5-
  • the ligand HL is selected from the group comprising: imidazole, 4-hydroxybenzimidazole, 1-benzylimidazole, 2-methylbenzimidazole, 2- phenylimidazole, 2-alkylimidazole, 2-arylimidazole, 4-alkylimidazole, 2-aminobenzimidazole, 2-alkylbenzimidazole, 4,5-diarylimidazole, 4,5-dialkylimidazole, 2,4,5-triarylimidazole, 2,4,5- trialkylimidazole, 4-arylimidazole, 5-alkylimidazole, 5-arylimidazole, 4-methylimidazole, 4- arylimidazole, 5-alkylimidazole, 5-arylimidazole, 5-methylimidazole, 2-(1 H-imidazol-2- yl)pyridine, 2-(1-hydroxyethyl)benzimidazole, 5-methylimidazole, 5-methylimi
  • the ligand HL is imidazole.
  • an aqueous hydrocarbon solvent is added under conditions of increased temperature (for example at least 40°C) in the presence of at least one “additional” catalyst.
  • additional catalyst it will be understood that the catalyst is supplementary to the reaction components, i.e., separate to components intrinsically present in together with the reaction components such as C1.3 alcohols, the catalyst of claim 1 , aqueous solvent and/or walls of a reactor apparatus.
  • an “additional” catalyst as contemplated herein may be considered to be an “extrinsic” catalyst in the sense that it is provided to the reaction as an individual reaction component.
  • An additional catalyst as contemplated herein may be selected from the following non-limiting examples of which include: base catalysts, acid catalysts, alkali metal hydroxide catalysts, transition metal hydroxide catalysts, alkali metal formate catalysts, transition metal formate/acetate catalysts, reactive carboxylic acid catalysts, transition metal catalysts, transition metal carbonyl halide catalysts, transition metal halides or carbonyls or sulphide or phosphine or imidazole or pyrazole or acetates or butrates catalysts, noble metal catalysts, water-gas-shift catalysts, and combinations thereof.
  • Methods of the invention may be performed using “additional” catalyst/s in combination with “intrinsic” catalyst/s.
  • the optimal quantity of an additional catalyst used in the methods of the invention may depend on a variety of different factors including, for example, the type or source of ethanol under treatment 1 st generation, 2 nd generation, CO derived and/or fossil derived, the volume of ethanol under treatment, the aqueous solvent utilised, the specific temperature and pressure employed during the reaction, the type of catalyst and the desired properties of the end product, selective to n-butanol or a mixture of higher alcohols besides the nature of the reactor apparatus.
  • an additional catalyst or combination of additional catalysts may be used in an amount of between about 0.01 % and about 50% w/v catalysts, between about 0.1 % and about 20% w/v catalysts, between about 0.1 % and about 10% w/v catalysts, between about 0.1% and about 5% w/v catalysts, between about 0.1% and about 2.5% w/v catalysts, between about 0.1% and about 1 % w/v catalysts, or between about 0.1% and about 0.5% w/v catalysts (in relation to the ethanol feed).
  • the hydrolysis catalysts may be base catalysts. Any suitable additional base catalyst may be used.
  • alumino-silicates including hydrated forms may be used to assist in dehydration (elimination) of water.
  • zeolites include ZSM-5, mordenite, Y, USY and beta zeolites, SAPO-1 1 , SAPO-34, molecular sieves, phosphates, zirconates, kaolinite, montmorillonite, pillared clays, hydrotalcites, and acid ionexchange resins such as Amberlyst-15®, and -35®, National SAC-13®, etc.
  • the removal of oxygen may be enhanced by thermal means involving decarbonylation, e.g., aldehydes (giving R3C-H and CO gas or C2H4) and decarboxylation of carboxylic acids in the material under treatment (giving R3C-H and CO2 gas) FIG. 2.
  • decarbonylation e.g., aldehydes (giving R3C-H and CO gas or C2H4) and decarboxylation of carboxylic acids in the material under treatment (giving R3C-H and CO2 gas) FIG. 2.
  • the rate of these reactions may be enhanced by the addition of acid and/or transition (noble) metal catalysts. Any suitable transition or noble metal may be used including those supported on solid acids or merely as the surface of the reaction apparatus.
  • Non-limiting examples include Pt/AI 2 O3/SiO2, Pd/AI 2 O3/SiO2, Ni/AI 2 O3/SiO2, Ru/AI 2 O3/SiO2, Os/AI 2 O3/SiO2, Cr/AI 2 O 3 /SiO2, Co/AI 2 O 3 /SiO2, Fe/AI 2 O 3 /SiO2, W/AI 2 O 3 /SiO2, Mo/AI 2 O3/SiO 2 , Re/AI 2 O 3 /SiO2, Cu/AI 2 O3/SiO2 and mixtures thereof.
  • a combined acid/base and hydrogenation catalyst may be used to enhance the removal of oxygen, for example, by hydrodeoxygenation, i.e., elimination of water via acid/base component and saturation of double bonds via metal component.
  • Any suitable combined acid/base and hydrogenation catalyst may be used including those supported on solid acids or in conjunction with ion exchange resins.
  • Non-limiting examples include Pt/AI 2 O 3 /SiO2, Pd/AI 2 O 3 /SiO2, Ni/AI 2 O 3 /SiO2, NiO/MoOs, CoO/MoOs, Ni0/W0 2 , zeolites loaded with noble metals (e.g., ZSM-5, Beta, ITQ-2), and mixtures thereof.
  • a water gas shift catalyst may be used to enhance the concentration of hydrogen into the reaction, i.e., via a water-gas shift reaction.
  • Any suitable water gas shift (WGS) catalyst may be used including, for example, transition metals, transition metal oxides, and mixtures thereof e.g., magnetite, platinum based WGS catalysts, finely divided copper and nickel, Raney® nickel, or copper and components of the reactor material and mixtures thereof.
  • catalysts which are suitable particularly advantageously for use in the process according to the invention is that of skeletal or metal sponge catalysts, which are referred to as “Raney® catalysts” may be used. These include Raney® nickel, cobalt or copper and copper-containing metal alloys in the form of a Raney® catalyst. Preferably, Raney® catalysts whose metal component consists of components contained in stainless steel to an extent of at least 70%, especially to an extent of 99%. Raney nickel may also be referred to as spongy nickel.
  • the catalyst further comprises a skeletal or metal sponge catalyst; preferably Raney nickel.
  • Raney nickel is a Nickel-Aluminium alloy.
  • the alloy has a Ni:AI ratio of about 1 :1.
  • the catalyst is provided as a single-site catalyst. In some embodiments, the catalyst is supported, preferably supported on an aluminosilicate framework. In some preferred embodiments, the catalyst is provided in step a. from at least 0.01 mol% to at most 1 .00 mol%, preferably from at least 0.02 mol% to at most 0.10 mol%, preferably about 0.05 mol%.
  • any kind of activated carbon may be used, such as activated charcoal.
  • the activated carbon is sourced from peat.
  • the activated carbon is steam activated.
  • the activated carbon is in powder form.
  • activated Charcoal Norit® greener alternative Norit® SA2 from peat, steam activated, powder from Merck may be used.
  • the process as disclosed herein comprising a catalyst that comprises activated carbon was found to reduce the amount of byproducts and impurities, while simultaneously improving the reaction rate, thereby promoting the desired coupling of alcohol compounds.
  • the multicomponent solvent system preferably comprises at least a basic aqueous hydrocarbon solvent phase, comprising at least two different hydrocarbons.
  • the solvent system is provided in step a. at a solvent/Ci.3 alcohol ratio of at least 1 to at most 10, preferably of at least 2 to at most 5, preferably about 3.
  • treatment with a subcritical aqueous hydrocarbon solvent may be advantageous in that less energy is required to perform the methods and the aqueous hydrocarbon solvent may be better preserved during reaction.
  • a subcritical aqueous hydrocarbon solvent it is contemplated that the additional use of one or more catalysts may be particularly beneficial in increasing the yield and/or selectivity to n-butanol.
  • the cost benefits of reduced input energy, /.e., to maintain subcritical rather than supercritical conditions and preservation of the solvent may significantly outweigh the extra cost incurred by additionally including one or more of the catalysts described herein.
  • the solvent preferably comprises a base selected from the group comprising: potassium hydroxide, sodium hydroxide, potassium ethoxide, sodium ethoxide, potassium t-butoxide, sodium t-butoxide, or combinations thereof, for example a eutectic mixture of sodium and potassium hydroxide.
  • the basic aqueous solvent phase comprises an alkali hydroxide, preferably KOH.
  • alkoxides of higher alcohols may be used as a base.
  • the solvent comprises a multicomponent solvent system, comprising at least two different hydrocarbons.
  • the solvent system is a thermomorphic multicomponent solvent system, preferably comprising a high boiling hydrocarbon solvent phase.
  • An additional high boiling hydrocarbon solvent as understood herein may be any solvent that enhances the selectivity of n-butanol as an extractive solvent, extracting the intermediates as outlined in FIG. 2 in addition to n-butanol thereby preventing the formation of higher alcohols from ethanol using the methods of the invention whilst allowing heating of the reactor apparatus within safe operation limits and stabilizing the catalyst.
  • Critical temperature (Tc) for ethanol is 240.95 °C
  • boiling point is 78.37 °C, /.e., it leads to unsafe reaction conditions if ethanol is heated alone under reaction conditions of the current invention. Addition of a higher boiling hydrocarbon solvent may also provide appropriate elevation of boiling point of ethanol.
  • the hydrocarbon solvent has at least two components of different polarity and have a high temperature dependent miscibility gap.
  • the reaction components are immiscible at low temperatures and completely miscible at elevated reaction temperatures.
  • Higher dilutions such as the one with an aqueous hydrocarbon solvent also, dissociates the acetaldehyde hydrate CH 3 CH(OH) 2 or semi-acetals CH 3 CH(OH)(OEt) back to acetaldehyde water and ethanol.
  • the hydrocarbon solvent may also act as an entrainer towards the effective distillation of azeotropes resulting in the reaction mixture such as ethanol/water, and n-butanol/water.
  • thermomorphic multicomponent solvent system The area and shape of the ‘phase separation zone’ of the applied thermomorphic multicomponent solvent system would depend upon various parameters as water to alcohol ratio, temperature and the type of alcohol, ethanol, or n-butanol and so on.
  • Ethanol is the only one with high solubility in water in contrast to butanol (73 g/L at 25 °C). At higher conversions, the solubility drops further thereby interaction with the active catalytic water phase will become low thereby increasing the selectivity to n-butanol.
  • the liquid phase will consist of unreacted ethanol, water, n-butanol, intermediates, and hydrocarbon solvent.
  • An appropriate choice of water/alcohol/hydrocarbon at reaction conditions may be used to carefully control this regime thereby the selectivity to n-butanol, based on the corresponding distribution coefficients.
  • the feed may contain one or more different aqueous alcohol/s such as fusel alcohols.
  • aqueous alcohol/s such as fusel alcohols.
  • the inclusion of alcohols is optional rather than a requirement.
  • the solvent comprises a mixture of two or more aqueous alcohols.
  • Suitable alcohols may comprise between C 3 -C 2 o.
  • suitable alcohols include linear or branched alcohols as 1-propanol, isopropyl alcohol, isobutyl alcohol, pentyl alcohol, amyl alcohols, hexanol and iso-hexanol.
  • the high boiling hydrocarbon solvent phase comprises a high boiling hydrocarbon selected from the group comprising: poly(ethylene glycol) (PEG) monoalkyl ethers, aliphatics (straight chain or branched), aromatics, aromatics with aliphatic substitutions, xylenes, cycloalkanes, substituted cycloalkanes, naphthenes, indenes, fluorene, biphenyls, Petrosolv 200-300, Petroflux ND, Petrosolv 250-450, SOLGAD 150, SOLGAD 200, SOLGAD 200 ULN, SOLGAD 150 ULN, sulfolane, dimethyl sulfoxide, dimethyl formamide, N- methyl pyrrolidone, N,N-dimethyl acetamide, 1 ,4-dioxane, anisole, propylene carbonate, benzyl alcohol, N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclo
  • the solvent comprises aromatics with aliphatic substitutions, such as mesitylene, which boils at 164°C.
  • the solvent comprises a Petrosolv solvent, which boils at 250°C.
  • Petrosolv 200-300 is not a stand-alone molecule but a cut from a distillation and has certain uses as a solvent. It consists of over 200 molecules in different ratios from GC.
  • the solvent comprises mesitylene and Petrosolv.
  • the solvent comprises xylene(s).
  • the solvent comprises be xylenes and mesitylene.
  • the solvent comprises be xylenes and a Petrosolv solvent.
  • the solvent comprises be xylenes, mesitylene, and a Petrosolv solvent.
  • the solvent comprises 1-propanol.
  • hydrocarbon solvents according to the invention may be recycled for use in subsequent reactions for conversion of ethanol into n-butanol.
  • the recycled solvents may be re-used during the process of cooling/de-pressurisation followed by distillation may be facilitated by performing the methods of the invention in a continuous flow system. This may be particularly advantageous in embodiments of the invention relating to extended operation at scales at or larger than pilot plant scale.
  • the recycling of solvents present in reaction components may allow for a situation where a top-up of solvent/ethanol is required during start-up operation.
  • the high boiling hydrocarbon solvent phase comprises a high boiling hydrocarbon in a ratio from 1 :1 to 1 :1000.
  • the ethanol: solvent ratio is 1 :100, 1 :10, 1 :5, 1 :3, 1 :2, 1 :1.
  • Higher solvent volumes are preferred for higher reaction temperatures (>250 °C), and lower solvent volumes are preferred for temperatures lower than 250 °C.
  • the feed may comprise more than about 5 wt. %, 10 wt. %, 15 wt. %, 20 wt. %, 25 wt. %, 30 wt. %, 35 wt. %, 40 wt. %, 45 wt. % or 50 wt. % of the hydrocarbon solvent or alcohols and combinations thereof.
  • the C1.3 alcohol is ethanol, preferably bio-ethanol.
  • the solvent/ethanol ratio is at least 2.0, preferably at least 3.0.
  • the bio-ethanol is obtained from fermentation.
  • ethanol feed it will be understood that it encompasses any ethanol comprising of two carbon alcohol, including both fossilised and non-fossilised or bio-forms. No limitation exists regarding the particular type of ethanol is utilised in the methods of the invention, although it is contemplated that certain forms of ethanol (e.g., bio-based ethanol) may be more suitable than others.
  • the ethanol may be rectified spirit, /.e., first product of the distilleries that is collected from rectifier column and contains 94.5% alcohol. Alternatively, it may be classified as ordinary denatured spirit (ODS), or special denatured spirit (SDS). Impurities or fusel alcohols may be a part of the feed. Such impurities may be aldehydes, acids, esters, higher alcohols, amyl alcohols. These may be either purified of may be used as a crude feed straight from the fermentation process.
  • ODS ordinary denatured spirit
  • SDS special denatured spirit
  • Impurities or fusel alcohols may be a part of the feed. Such impurities may be aldehydes, acids, esters, higher alcohols, amyl alcohols. These may be either purified of may be used as a crude feed straight from the fermentation process.
  • the ethanol may be extra neutral alcohol (ENA) or neutral spirit (NS).
  • EDA extra neutral alcohol
  • NS neutral spirit
  • the ethanol may be fuel grade ethanol also known as absolute alcohol (AA), comprising of a blend of fusel alcohols and/or denaturing agents.
  • AA absolute alcohol
  • the ethanol may be derived from 1st generation (food based), 2nd generation (waste based) or via CO/CO2 recycling or other.
  • ethanol may comprise more than about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90% or 95 wt. % of the feed.
  • the ethanol is higher grade ethanol, such as fuel grade ethanol or G1 ethanol.
  • the concentration of ethanol in the feed may be above about 98 wt. %, above about 95 wt. %, or above about 90 wt. %.
  • the concentration of water may be above about 10 wt. %, above about 8 wt. %, above about 6 wt. %, above about 5 wt. %, above about 4 wt. %, or above about 3 wt. %.
  • the concentration of water is between about 1 wt. % and about 10 wt. %.
  • the water is recycled from the product of the process. For example, a portion water present following completion of the reaction may be taken off as a side stream and recycled into the feed. It has been observed that if the water concentration is too high, the conversion rate drops.
  • fusel alcohols may be present in the ethanol feed.
  • Fusel alcohols are higher boiling and volatile than ethanol, and therefore present resulting from the fermented mash. These may be a mixture of primarily alcohols, including active amyl alcohol (2-methyl-1 -butanol), isoamyl alcohol, isobutyl alcohol, 1-propanol and, n-amyl alcohol, n-butyl alcohol, and methionol.
  • the concentration of fusel alcohols may be above about 10wt.%, above about 5wt.% or above about 3 wt. %. It has been observed that the presence of fusel alcohols increases the conversion rate.
  • ethanol may be fed to the reactor as a liquid stream.
  • the ethanol stream is substantially free of external hydrogen, e.g., less than 0.5 wt.% hydrogen, less than 0.1 wt.%, or less than 0.01 wt.%.
  • the feed stream may also comprise other molecules, such as high boiling hydrocarbon solvents.
  • Inert gases may be in the gaseous stream and thus may include methane, argon, nitrogen, or helium.
  • no hydrogen is introduced with the gaseous stream, and thus the gaseous stream is substantially free of hydrogen.
  • the hydrogen needed for the intermediate reactions may be produced in-situ for example with sodium formate, potassium formate, or ammonium formate.
  • the present catalyst system is such that no additional hydrogen is required.
  • the catalyst/s may be added to ethanol, aqueous hydrocarbon solvent, before heating/pressurisation to target reaction temperature and pressure, during heating/pressurisation to target reaction temperature and pressure, and/or after reaction temperature and pressure are reached.
  • the timing of catalyst addition may depend on the desirable output. For example, highly selective n-butanol formation may benefit from catalyst addition close to or at the target reaction temperature and pressure, whereas a mixture of higher alcohols may have a broader process window for catalyst addition, i.e., the catalysts may be added prior to reaching target reaction temperature and pressure.
  • an aqueous hydrocarbon solvent is added under conditions of increased temperature and pressure in the presence of at least one “additional” catalyst.
  • an “additional” catalyst will be understood to indicate that the catalyst is supplied supplementary to catalysts intrinsically present in the reaction.
  • step a. is performed at ambient temperature.
  • step b. comprises one or more, preferably all, of the steps of: b1. heating the mixture to a temperature T1 in a time frame At1 ; b2. heating the mixture to a temperature T2 in a time frame At2; and, b3. maintaining the mixture at the temperature T2 during a time frame At3.
  • T2 is from at least 140°C to at most 500°C, preferably from at least 150°C to at most 400°C, preferably from at least 160°C to at most 300°C, preferably from at least 170°C to at most 260°C, preferably from at least 180°C to at most 240°C, preferably from at least 190°C to at most 220°C, preferably about 200°C.
  • the specific time period over which the conversion to n-butanol may be achieved upon reaching a target temperature and pressure, /.e., the “retention time or residence time” may depend on a number different factors including, for example, the type of hydrocarbon solvent used, the percentage of ethanol in the solvent, the amount of water, the types of catalyst/s as defined herein, in the mixture and their various concentration/s, and/or the type of reactor apparatus as described above in which the methods are performed. These and other factors may be varied to optimise a given method to maximise the yield and/or reduce the processing time.
  • the retention time is sufficient to convert all or substantially all the ethanol used as a feed into n-butanol.
  • T1 is from at least 60°C to at most 80°C, preferably about 70°C.
  • T2 is from at least 140°C to at most 500°C, preferably from at least 150°C to at most 400°C, preferably from at least 160°C to at most 300°C, preferably from at least 170°C to at most 260°C, preferably from at least 180°C to at most 240°C, preferably from at least 190°C to at most 220°C, preferably about 200°C.
  • At1 is from at least 90 to 180 minutes, preferably about 120 minutes. In some embodiments, At2 is from at least 30 to 90 minutes, preferably about 60 minutes.
  • At3 is from at least 120 to 360 minutes, preferably about 240 minutes.
  • Reaction mixes that do not contain a significant proportion of hydrocarbon solvent may require a very fast initial conversion to generate some solvent in-situ.
  • the incorporation of high boiling hydrocarbon component into the reaction mixture as described herein allows the component to act as a solvent thus alleviating the requirement for rapid heating/pressurisation.
  • pressure will generally change from atmospheric to target pressure during the time it takes to cross the pump, i.e., close to instantaneous, whereas in a batch system it will mirror the time that it takes to heat the mixture up.
  • the reaction mixture may be brought to a target temperature and/or pressure in a time period of between about 30 seconds and about 360 minutes.
  • the reaction mixture may be brought to a target temperature and/or pressure in a time period less than about 15 minutes, less than about 10 minutes, less than about 5 minutes, or less than about 2 minutes.
  • the reaction mixture may be brought to a target pressure substantially instantaneously and brought to a target temperature in less than about 20 minutes, less than about 10 minutes, or less than about 5 minutes.
  • the reaction mixture may be brought to a target pressure substantially instantaneously and brought to a target temperature in less than about two minutes.
  • the reaction mixture may be brought to a target pressure substantially instantaneously and brought to a target temperature in between about 1 and about 2 minutes.
  • At1 residence times are about 360 minutes, 240 minutes, 180minutes, 120minutes, 60 minutes, 45 minutes, 30 minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes or less than about 5 minutes.
  • the residence time is less than about 120 minutes, 60 minutes, 45 minutes, 30 minutes, 25 minutes, 20 minutes, 15 minutes, 10 minutes or more than about 5 minutes.
  • At2, and At3 residence time is between about 1 minute and about 360 minutes.
  • the residence time is between about 10 minutes and about 120 minutes, between about 20 minutes and about 140 minutes, between about 30 minutes and about 180 minutes, or between about 40 minutes and about 240 minutes.
  • the retention/residence time is between about 20 minutes and about 30 minutes.
  • the reaction mixture may be cooled to between about 140° C and about 200° C, between about 150° C and about 200° C, preferably between about 160° C and about 190° C, and more preferably about 150° C, in a time period of less than about 10 minutes, preferably less than about 7 minutes, more preferably less than about 6 minutes, preferably between about 4 and about 6 minutes, and more preferably about 5 minutes.
  • the temperature may further reduced to ambient temperature with concurrent de-pressurisation by fast release into a cool aqueous medium, e.g., cooled water.
  • the current invention utilises an alcohol feed (ethanol) which is converted to another alcohol (n-butanol).
  • the retention time required will be influenced by the proportions of various components in the reaction mixture (e.g., water, solvent, alcohol catalysts etc.).
  • step b. is performed at a pressure of at least 2 bar to at most 250 bar. This allows to keep the mixture in the liquid phase rather than gas phase to ensure the selectivity. Higher pressure helps stay in the liquid phase.
  • the inventors have found that the present components provide a homogeneous dispersion.
  • step b. comprises a stirring rate modulated from 0 rpm to 5000 rpm, preferably from 200 rpm to 1200 rpm.
  • the mixture is stirred vigorously enough to be able to benefit thermomorphic multicomponent hydrocarbon solvent system, /.e., temperature dependency of the miscibility gap is as high as possible, to switch from homogeneous to biphasic separation at low energy consumption, elimination of liquid-liquid interface to enable unification of reaction components, and only a single solvent is preferred that can homogenise catalyst, ethanol feed, and preferentially n-butanol phase upon cooling such that additional separation units for product purification and solvent recovery are dispensable.
  • thermomorphic multicomponent hydrocarbon solvent system /.e., temperature dependency of the miscibility gap is as high as possible, to switch from homogeneous to biphasic separation at low energy consumption, elimination of liquid-liquid interface to enable unification of reaction components, and only a single solvent is preferred that can homogenise catalyst, ethanol feed, and preferentially n-butanol phase upon cooling such that additional separation units for product purification and solvent recovery are dispensable.
  • a bubble column reactor type mechanism may be used to ensure good heat and mass transfer rates therefore, excellent dispersion, with no moving parts, compactness, easy operating and low maintenance and operating costs.
  • a Teflon coated stir bar may be used with a hot stir plate with a suitably sized aluminium metal block equipped with a temperature probe and controlled stirring but with limited efficiency may also be used.
  • step b. is performed in a batch reactor, a flow reactor, a continuous flow reactor, a tubular reactor, or a microchannel reactor; preferably step b. is performed in a batch reactor or a tubular reactor.
  • heat transfer and mass transfer or mixing limitations rather than the fundamental kinetics, control the reaction rate.
  • the conversion of two equivalents of ethanol to one equivalent of n-butanol and water each at ambient conditions is -46.6 kJ/mol, /.e., such an exothermic reaction may require a couple of hours as described above to carry out in a batch reactor, not because of any kinetic constraint, but because of the time necessary to remove the heat of reaction and to operate in a safe manner.
  • the reactor may be any suitable batch reactor or combination of reactors.
  • the reactor comprises a fixed bed reactor or a series of such reactors.
  • the reactor is a gas flow catalytic reactor or a series of such reactors.
  • the reactor is a continuous stirred tank reactor or a fluidised bed reactor or a tubular reactor.
  • continuous flow may facilitate the accelerated implementation and/or removal of heat and/or pressure applied to the mixture. This may assist in achieving the desired rates of mass and heat transfer, heating/cooling and/or pressurisation/de-pressurisation.
  • Continuous flow may also allow the retention time of the reaction mixture to be tightly controlled. Without limitation to a particular mode of action, it is postulated that the increased speed of heating/cooling and/or pressurisation/de-pressurisation facilitated by continuous flow conditions along with the capacity to tightly regulate retention/residence times assists in preventing the occurrence of undesirable side-reactions as cited in FIG. 2 as the reaction mixture heats/pressurises and/or cools/de-pressurises.
  • Continuous flow is also believed to enhance reactions responsible for conversion of ethanol to n-butanol by virtue of generating mixing and shear forces believed to aid in emulsification which may be an important mechanism involved in the transport and “storage” of the n-butanol generated away from the reactive surfaces of the catalyst as well as providing interface surface area for so-called ‘on-water catalysis’.
  • the methods of the invention are performed under conditions of continuous flow.
  • continuous flow refers to a process wherein ethanol mixed with a high boiling aqueous hydrocarbon solvent in the form of a mixture (with or without additional catalysts) is subjected to:
  • Continuous flow conditions as contemplated herein imply no particular limitation regarding flow velocity of the mixture provided that it is maintained in a stream of continuous movement.
  • the minimum (volume-independent) flow velocity of the mixture along a given surface exceeds the settling velocity of solid catalyst components within the mixture, /.e., the terminal velocity at which a suspended particle having a density greater than the surrounding solution moves (by gravity) towards the bottom of the stream of mixture, allowing for uniform diffusion.
  • the minimum flow velocity of the mixture may be above about 0.001 cm/s, above about 0.05 cm/s, preferably above about 0.5 cm/s and more preferably above about 5 cm/s.
  • the upper flow velocity may be influenced by factors such as the volumetric flow rate and/or retention/residence time. This in turn may be influenced by the components of a particular reactor apparatus utilised to maintain conditions of continuous flow.
  • a suitable reactor apparatus will generally comprise heating/cooling, pressurizing/de-pressuring and reaction components in which a continuous stream of reaction mixture is maintained.
  • a suitable flow velocity (under conditions of continuous flow) may be advantageous in preventing scale-formation or catalyst deposition along the length of a particular surface that the reaction mixture moves along, e.g., vessel walls of a reactor apparatus and/or generating an effective mixing regime for efficient heat transfer into and within the reaction mixture.
  • the surface-to-volume ratio is a function of reactor size. Larger reactors have smaller surface-to-volume ratios. For example, 100mL flask has a surface/volume (cm 2 /cm 3 ) of 1 , while that for a 189 L (50-gallon) reactor is 0.08, for a 1m 3 reactor it is 0.06 and for a flat microchannel reactor with width approximately 100 pm is 200.
  • the continuous stirred tank reactor or a tubular reactor is favoured over a batch or a CSTR reactor.
  • a synthetic procedure that works well in a small glass insert in R&D may pose huge problems when transferred directly to larger vessels in a kilo laboratory or pilot plant and subsequently to a commercial plant.
  • a single flow reactor e.g., a microreactor
  • a continuous stirred tank reactor or a fixed bed reactor may be used to support continuous production.
  • several specialised reactors may also be used: (1) microreactors, (2) continuous tubular reactors/plug flow reactor, (3) bubble column reactor (BCR), (4) reverse flow reactors and (4) CSTRs with continuous tubular reactor in tandem.
  • reverse flow reactors heat exchange for heating the feed flow and cooling the product flow may be combined in the fixed bed reaction section, saving on heat exchanger cost.
  • the reactor may also be a high pressure reactive distillation, wherein reactive distillation (RD), benefits can be realised by using the reaction to improve separation of unreacted ethanol, and products as water, n-butanol and higher alcohols (e.g., overcoming azeotropes, reacting away contaminants, avoiding difficult separations) wherein, the catalyst components are embedded in the column packing material to improve efficiency or by using separation to improve reactions (e.g., enhancing overall rates, overcoming reaction equilibrium limitations, improving selectivity) - the maximum effect being achieved when both aspects apply.
  • RD reactive distillation
  • flow reactors e.g., microreactors
  • flow reactors with their high surface-to- volume ratios may be used to absorb the heat created from the reaction much more efficiently than a batch reactor.
  • a large batch reactor there is a strong temperature gradient from the cooled surface of the reactor to its centre.
  • a microreactor much less heat is created, and it only takes a few millimetres of path length for the stream to cool down to the operational temperature. This results from higher heat transfer in flow reactors compared with batch reactors.
  • volumetric heat transfer coefficient 10 -2 to 10' 3 while for shell and tubes it is 0.2 and for plates or glass fluidic modules it is 1.3- 1.7 MW/m 3 K.
  • a microreactor may offer further reduction of carbon footprint of the overall process.
  • miniaturised flow reactors may be designed in a variety of shapes, lengths, diameters, and construction materials.
  • the key feature of every flow design unit is the ability to maintain a steady flow rate though the reactor over process time. Additional features may incorporate the implementation of baffles to promote mixing and/or static mixers to increase turbulent flow.
  • Flow reactors are typically designed to have reduced reactor volumes, physical footprint, and energy requirements when compared with their batch reactor counterparts.
  • reactors Due to their design and size, these reactors are operated in a safer environment and offer the benefits of increasing reaction rates (e.g., at a higher temperature than batch reactors), operating solvent- less or low solvent/ethanol ratios, enhancing mixing, and effectively removing the heat produced by the exothermic reaction due to a more efficient heat transfer capacity and well- defined reaction concentration profile that enables to control the conversion of ethanol and n- butanol to Ce, Cs and Cw alcohols.
  • the ability to control accurately the residence time in the reaction zone gives greater reproducibility of product distribution and process robustness in terms of operating conditions for flow process intensification.
  • SDR spinning disk reactor
  • a spinning tube-in-a-tube reactor specialised reactors designed for multiphase catalytic reactions.
  • tubular reactors designed for multiphase catalytic reactions can be used as a standalone unit or as a combination of, thereby to optimise the conversion and selectivity to n-butanol.
  • the C1.3 alcohol is converted to n-butanol. In some preferred embodiments, the C1.3 alcohol is converted to Ce-8 alcohols.
  • the reaction achieves favourable conversion of ethanol and favourable selectivity, and productivity to n-butanol.
  • conversion refers to the amount of ethanol in the feed that is converted to a compound other than ethanol. Conversion is expressed as a percentage based on ethanol in the feed.
  • the conversion of ethanol may be at least 20%, e.g., at least 30%, at least 40%, or at least 60%, or at least 80%.
  • Selectivity is expressed as the ratio of the amount of carbon in the desired products and the amount of carbon in the total products.
  • the selectivity to n-butanol is at least 30%, e.g., at least 40%, or at least 60%, or at least 90%.
  • the catalyst selectivity to Ce+ alcohols is at least 5%, e.g., at least 10%, at least 20%, or at least 25%.
  • Preferred embodiments of the process demonstrate a low selectivity to undesirable products, such as di-ethyl ether, methane, ethane and ethene as shown in FIG. 2.
  • the selectivity to these undesirable products preferably is less than 20%, e.g., less than 5% or less than 1%. More preferably, these undesirable products are not detectable. More preferably, these undesirable products are not formed.
  • production of n-butanol from ethanol in accordance with the methods of the invention may be enhanced by the presence of “intrinsic” catalyst/s that are innately present in a given reaction component such as, for example, in ethanol, aqueous solvent, and/or vessel walls of a reactor apparatus in which the reaction mixture may be treated.
  • the methods of the invention may be performed using “additional” catalysts in combination with “intrinsic” catalysts, or, “intrinsic” catalysts as standalone depending on reactor apparatus type and material.
  • the optimal quantity of an intrinsic catalyst used in the methods of the invention may depend on a variety of different factors including, for example, the type of ethanol under treatment, the volume of ethanol under treatment, the aqueous hydrocarbon solvent utilised, the specific temperature and pressure employed during the reaction, the type of catalyst and the desired conversion, and selectivity to n-butanol.
  • an intrinsic catalyst or combination of intrinsic and additional catalyst may be used in an amount of between about 0.1% and about 20% w/v catalysts, between about 0.1% and about 10% w/v catalysts, between about 0.1 % and about 5% w/v catalysts, between about 0.1% and about 2.5% w/v catalysts, between about 0.1% and about 1 % w/v catalysts, or between about 0.1 % and about 0.5% w/v catalysts (in relation to the ethanol).
  • an “intrinsic” catalyst used in the reaction process may be an alkali and/or alkaline earth metal salt, e.g., potassium, calcium and/or sodium salts.
  • alkali metal hydroxides and carbonates may be effective in reducing the oxygen content of the aldol condensation products.
  • the optimum catalyst concentration (in the reaction itself) of an alkali metal hydroxide and/or alkali metal carbonate catalyst under a given set of otherwise substantially constant reaction conditions may be in the range of about 0.1 Molar to about 5 Molar. In some preferred embodiments, the concentration may be about 0.1 Molar to about 2 Molar.
  • the concentration of alkali metal hydroxide and/or alkali metal carbonate catalyst is less than about 25% w/w; between about 5% and about 15% w/w.
  • bio-ethanol from distilleries may comprise a variable amounts of impurities, e.g., between 0.1% to about 2% impurities, and the impurities in turn may comprise various amounts of alkali salts, e.g., potassium, sodium salts and/or calcium salts resulting from extraction of fusel alcohols.
  • alkali salts e.g., potassium, sodium salts and/or calcium salts resulting from extraction of fusel alcohols.
  • Other metals that are present in fuel grade ethanol my comprise of manganese, iron, lead, cobalt, cadmium, zinc, copper, nickel in varying amounts. These may be catalysts for a range of reactions under the reaction conditions of the present invention including those reactions described in FIG. 2.
  • an aqueous hydrocarbon solvent used in the methods of the invention may provide intrinsic catalysts to the reaction.
  • Non-limiting examples of these catalysts include hydronium and/or hydroxide ions of water. Additionally or alternatively, “intrinsic” catalysts may be provided by the vessel walls of a reactor apparatus in which the reaction may be treated. Non-limiting examples of materials commonly used for reactor construction, i.e., including reactor vessel walls, are alloys of iron with other metals including chromium, nickel, manganese, vanadium, molybdenum, titanium and silicon.
  • “intrinsic” catalysts that may be provided by the vessel walls of a reactor apparatus are transition/noble metals.
  • Non-limiting examples of “intrinsic” catalysts may be provided by the vessel walls of a reactor apparatus include iron metal, hydroxides of iron, oxides of iron, carbonates of iron, hydrogen carbonates of iron, acetates of iron; nickel metal, hydroxides of nickel, oxides of nickel, carbonates of nickel, hydrogen carbonates of nickel; chromium metal, hydroxides of chromium, oxides of chromium, carbonates of chromium, hydrogen carbonates of chromium; manganese metal, hydroxides of manganese metal, oxides of manganese metal, carbonates of manganese metal, and/or hydrogen carbonates of manganese metal.
  • Hydroxides may be present by virtue of reaction of the metals with water and alkaline “additional” catalysts.
  • Oxides may be present by virtue of reaction of metals with oxygen-containing compounds and as passivating layers.
  • Carbonates and hydrogen carbonates may be present by virtue of reactions of metals, metal oxides and/or metal hydroxides with carbon dioxide generated in- situ by decarboxylation reactions.
  • Acetates of metals may be present by virtue of reactions of metals, metal oxides, metal hydroxides, metal hydrogen carbonates and metal carbonates with acetic acid generated in-situ by hydrolysis.
  • Metals and metal compounds associated with surfaces made of steel and similar materials may catalyse various reactions including, but not limited to, one or more of the reactions described in FIG. 2.
  • intrinsic catalysts e.g., alkali salts such as potassium, sodium and calcium salts may be transferred to the aqueous hydrocarbon phase during the reaction. Because significant concentrations of such catalysts, e.g., alkali salts of potassium, sodium and calcium may be present in ethanol processed according to methods of the invention, in certain embodiments aqueous hydrocarbon phases containing dissolved catalysts, e.g., potassium, sodium, and/or calcium salts may be recycled.
  • intrinsic catalysts from various reaction components may be renewed in situ alleviating or reducing the need to provide “additional” catalysts in subsequent rounds of ethanol conversion.
  • This may be particularly advantageous in embodiments of the invention relating to extended operation at scales at or larger than pilot plant scale.
  • the recycling of intrinsic catalysts present in reaction components e.g., alkali salts may allow for a situation where “additional” catalysts are required during start-up operation only.
  • the “intrinsic” catalyst and catalyst components may be preformed and analysed or added as individual components as molar equivalents of the ethanol feed. This may be particularly advantageous in embodiments of the invention relating to extended operation on a commercial scale and related to the long-term storage of the catalysts.
  • the reaction vessel acts as an intrinsic catalyst.
  • the reactor apparatus may be used to enhance the conversion of ethanol. Any reactor apparatus that is made from 316 stainless steel, an alloy of Fe, Cr (12- 20%), Ni (10-14%), Mo (2-3)%, Mn ( ⁇ 2%) and in some cases smaller amounts of Si ( ⁇ 1%), P( ⁇ 0.045%), and S( ⁇ 0.03%), that is generally considered to be inert and highly corrosion resistant, as it passivates itself through the build-up of a mechanically strongly adherent chromium oxide layer of ⁇ 100 A thickness, for example, may be used to enhance the removal of oxygen, i.e., elimination of water from ethanol when treated with appropriate strong base or acid.
  • austenitic stainless steel or martensitic stainless steel or ferritic stainless steel that is generally considered to be inert and highly corrosion resistant, as it passivates itself through the build-up of a mechanically strongly adherent chromium oxide layer of ⁇ 100 A thickness, for example, may be used to enhance the removal of oxygen, i
  • the process further comprises the step of: c. distilling the higher alcohols.
  • the separation of multi-component mixtures preferably uses a direct or indirect sequence of at least two distillation columns.
  • a dividing-wall column may also be applied.
  • DWC offers some major benefits compared with classic distillation design: high thermodynamic efficiency due to reduced remixing effects, 25-40% lower energy requirements, high purity for all product streams, reduced maintenance costs, small footprint and up to 30% lower investment costs due to the reduced number of equipment units.
  • the first step may be carried out in a pre-concentration distillation column (PDC) that recovers ethanol up to 92.4-94%wt.
  • PDC pre-concentration distillation column
  • the second step is ethanol dehydration up to concentrations above the azeotropic composition.
  • Extractive distillation presents relatively high energy costs, it is still the option of choice in the case of large-scale production of bio-ethanol fuel - being preferred over pervaporation, adsorption, pressure- swing distillation, azeotropic distillation, or hybrid methods combining these options. This may be applied if the production of n-butanol were to be co-located to an ethanol producing facility.
  • Extractive dividing-wall column (E-DWC) systems may be used for extractive distillation, including or not the pre-concentration distillation column (PDC).
  • a subsequent molecular sieve distillation to further purify butanol with MFI-type zeolite membranes (e.g., silicalite-1), because of its well-defined pore structure (ca. 0.5 nm) and high hydrophobicity, may be deployed to obtain n-butanol with purity of 99.99%.
  • MFI-type zeolite membranes e.g., silicalite-1
  • the present invention relates to use of a catalyst as described herein, in the conversion of a C1.3 alcohol to higher alcohols
  • GC-FID Gas chromatogram - flame ionisation detector
  • GC-MS gas chromatogram - mass spectra
  • G1 Ethanol feed with ASTM D4806 standard for denatured fuel ethanol for blending with gasolines for use as automotive spark ignition engine fuel with specifications as listed below Table 2.
  • Acidity as acetic acid, mg/kg, (% by mass) [mg/L], 70 (0.0070) D7795 max pHe 6.5-9.0 D6423
  • D7328 G2 Ethanol specification used for tests as neutral ethanol derived by fermentation of cereals and carbohydrate containing juices of sugar beet and/or sugar cane with the specifications as listed in Table 3 and 4. Table 3.
  • a representative crude sample reaction mixture (300mL) resulting from the tests with a GC- FID such as the one shown in FIG. 8 was transferred to a 1000mL round bottom flask equipped with a stir bar and a fractionating column 50cm long fitted with iron or copper wool to increase the number of theoretical plates.
  • the distillation is preferably carried out at atmospheric pressure, although it is possible to operate at sub-atmospheric or super-atmospheric pressures, if desirable under certain circumstances.
  • the number of trays in the column and amount of heat transferred to the material being purified in the column are sufficient to produce a liquid stream of purified n-butanol containing at least about 97-99% of n-butanol.
  • distillation products have the following compositions as judged by GC-FID: Fraction 1 : 78.5 °C, 12.4g (ethanol);
  • the catalyst was present at 0.0494 mol% and the solvent/ethanol ratio was 3. Results are shown in Table 5 below.
  • Run 1 corresponds to the details set out in Example 22.
  • Runs 2 and 3 correspond to the details set out in Example 21.
  • Run 4 corresponds to the details set out in Example 20.
  • Run 5 corresponds to the details set out in Example 19.
  • Run 6 corresponds to the details set out in Example 18.
  • Runs 7 and 8 correspond to the details set out in Example 17.
  • Runs 2 and 3 were identical, except for the fact that Run 3 was performed after leaving the catalyst exposed to elements for 4 months.
  • Runs 7 and 8 were identical, except for the fact that Run 8 was performed after leaving the catalyst exposed to elements for 6 months. This illustrates the relative stability in air/water of the catalyst system.

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  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Abstract

L'invention concerne un procédé de conversion d'un alcool C1-3 en alcools supérieurs, le procédé comprenant les étapes suivantes : a. pré-mélanger un alcool C1-3, un catalyseur et un système de solvant à composants multiples, pour former un mélange liquide ; et b. faire chauffer le mélange liquide, ce qui permet d'obtenir des alcools supérieurs ; le système de solvant à composants multiples comprenant au moins une phase de solvant hydrocarboné aqueux basique comprenant au moins deux hydrocarbures différents ; le solvant comprenant une base choisie dans le groupe comprenant : l'hydroxyde de potassium, l'hydroxyde de sodium, l'éthoxyde de potassium, l'éthoxyde de sodium, le t-butoxyde de potassium, le t-butoxyde de sodium, ou des combinaisons de ceux-ci, par exemple un mélange eutectique d'hydroxyde de sodium et de potassium ; et le catalyseur comprenant un complexe de type (HL)M(OH)n(H2O)m et du charbon actif.
PCT/EP2023/082825 2022-11-23 2023-11-23 Oligomérisation d'alcools WO2024110575A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015031561A1 (fr) 2013-08-30 2015-03-05 Bp Corporation North America Inc. Conversion catalytique d'alcools
WO2019193079A1 (fr) 2018-04-05 2019-10-10 Alma Mater Studiorum - Universita' Di Bologna Procédé amélioré pour la transformation d'alcools aliphatiques primaires en alcools aliphatiques supérieurs

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015031561A1 (fr) 2013-08-30 2015-03-05 Bp Corporation North America Inc. Conversion catalytique d'alcools
WO2019193079A1 (fr) 2018-04-05 2019-10-10 Alma Mater Studiorum - Universita' Di Bologna Procédé amélioré pour la transformation d'alcools aliphatiques primaires en alcools aliphatiques supérieurs

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