Process for preparing bio-based olefins from primary alcohols - Patents.com

Abstract

While propylene is an important industrial intermediate for the production of propylene oxide and polypropylene, isobutylene is similarly widely used in the production of various industrially important products, such as butyl rubber. Both propylene and isobutylene are obtained by catalytic or steam cracking of fossil feedstocks, and the development of commercially viable processes for the direct conversion of alcohols to either material would therefore be of great interest, particularly in light of the increasing demand for both propylene and isobutylene as fossil resources become depleted and / or expensive to use. The present invention relates to a process for preparing lower olefins from primary alcohols. More particularly, the present invention relates to a process for the conversion of primary alcohols to lower olefins, wherein the primary alcohols are obtained from renewable resources.

Description

[Technical Field]

[0001] The present invention relates to a process for preparing lower olefins from primary alcohols. More particularly, the present invention relates to a process for the conversion of primary alcohols having at least one hydrogen atom attached to a carbon atom adjacent to one bearing an alcohol group to lower olefins, wherein the primary alcohol is obtained from a renewable resource. [Background technology]

[0002] Biomass is considered a CO2-neutral energy carrier and is one of the most abundant and renewable natural resources. In recent years, biomass conversion for biofuel production has attracted significant effort and investment, both as a result of market conditions and in response to various government initiatives and mandates. With the increasing availability and decreasing cost of bioethanol, opportunities have been explored for using bioethanol not only as a biofuel but also as a feedstock for producing various renewable-source-derived chemicals.

[0003] While the most commercially advanced effort is the dehydration of bioethanol to produce ethylene, the conversion of bioethanol to propylene and isobutylene is also being investigated. Propylene is an important industrial intermediate for the production of propylene oxide and polypropylene, while isobutylene is similarly widely used in the production of various industrially important products, such as butyl rubber. Both propylene and isobutylene are obtained by catalytic or steam cracking of fossil feedstocks, and the development of commercially viable processes for the direct conversion of alcohol to either material would therefore be of great interest, especially given the increasing demand for both propylene and isobutylene as fossil resources become depleted and / or expensive to use.

[0004] Natural raw materials are in particular substances obtained by processing from plants or plant parts (or even animals). A characteristic feature of raw materials from renewable sources is a significantly higher proportion of carbon isotopes.14 C. This determination allows the proportion of renewable raw materials to be determined experimentally. Renewable resources differ from those obtained by chemical synthesis or petroleum processing in that they are less uniform. The composition of renewable resources varies greatly because it depends on factors such as the climate and region in which the plant grows, the season of harvest, variation between species and subspecies, and the type of extraction process used for extraction (extrusion, centrifugation, filtration, distillation, cutting, pressing, etc.).

[0005] Fusel oil is formed as a by-product of alcoholic fermentation and consists of a mixture of several alcohols, primarily amyl alcohol, with smaller amounts of propanol, n-butanol, and isobutanol depending on the refining process used. Depending on the carbohydrate source for the fermentation process and the organism used, fusel oil levels are typically 0.2-3.0% relative to the target alcohol produced. Fusel oil is a co-product of alcoholic fermentation. These oils are produced by yeast in anaerobiosis from nitrogenous materials and are recovered after rectification or on the midplate of the column.

[0006] Fusel oils, sometimes called "amyl oil" or "fusel," have different compositions depending on their origin (potato, beet, wheat, barley, etc.). They are mixtures of 5% to 20% water and 60% to 95% alcohol, primarily consisting of linear or branched alkanols containing 2 to 5 carbon atoms, with impurities (furfurol, ethers, fatty acids, etc.) that can amount to up to 15% ethanol, 2-methyl-1-butanol, and 3-methyl-1-butanol in extreme cases. Ethanol, 2-methyl-1-butanol, and 3-methyl-1-butanol may be used as starting materials for the preparation of several olefins that find application in various industries.

[0007] Some olefins (such as isobutylene and isoamylene) are most commonly used as starting materials for other products, as opposed to being used directly in some end uses. While not exhaustive, this literature reveals several uses of the olefins isobutylene and / or isoamylene. These include: (i) hydrocarbon resin modification (softening point / Tg / molecular weight control), (ii) fuel additives by oligomerization (typically dimerization) for octane boosters or by etherification with methanol or ethanol, and (iii) synthetic building blocks, e.g., precursors to diolefins, flavor / fragrance enhancers, antioxidants, typically alkylphenols, or as synthons for the preparation of fine chemicals or pharmaceuticals.

[0008] Therefore, it was an object of the present invention to produce olefins from alcohols found in renewable feedstocks. A further object of the present invention was to produce olefins having a pMC greater than 90 using renewable feedstocks in comparable quality and yield when produced using pure feedstocks.

[0009] Yet another object of the present invention was to develop a robust process that leads to olefins of high quality, higher yields, and with pMCs greater than 90, regardless of the nature of the raw materials used (renewable sources containing some impurities or pure sources). Summary of the Invention [Means for solving the problem]

[0010] Surprisingly, the above objectives have been achieved by the method of the present invention.

[0011] Accordingly, a first aspect of the present invention is a process for preparing lower olefins having 4 to 7 carbon atoms, comprising: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight and / or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidative decarboxylation of the carboxylic acid to an olefin having one less carbon atom than the starting alcohol.

[0012] A second aspect of the present invention relates to a process in which the starting material, i.e., a C5-C8 primary alcohol, has a pMC of greater than 90 as measured by the method described in ASTM standard D6866 (the current version is D6866-22), which defines the concept of "percent modern carbon" or pMC. A "bio-based" material has a pMC of 100%.

[0013] A third aspect of the present invention relates to a process in which the starting material, i.e., a linear and / or branched C5 to C8 primary alcohol having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, is converted to at least one lower hydrocarbon having C4 to C7 carbon atoms in a concentration of 60 to 99% by weight in a yield of at least about 80% by weight of the maximum theoretical molar yield.

[0014] Another aspect of the invention relates to a process for preparing isobutene starting from 3-methyl-1-butanol obtained from fusel oil using a combination of oxidation of the alcohol to 3-methylbutanoic acid and oxidative decarboxylation to isobutene. Although the individual steps are known reactions, they have not been described for this particular substrate and have not been combined as a means to obtain isobutene with a pMC greater than 90 (pMC>90%). DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, when a group is defined as including at least a certain number of embodiments, this preferably also means that the group consists of only those embodiments. Furthermore, in the present specification and claims, terms such as "first," "second," "third," "a," "b," "c," etc., and similar terms are used to distinguish between similar elements and do not necessarily denote sequential or chronological order. It is to be understood that such terms are interchangeable under appropriate circumstances, and that the embodiments of the invention described and claimed herein can be practiced in orders other than those described or illustrated herein. Where terms such as "first", "second", "third", or "(A)", "(B)" and "(C)", or "(a)", "(b)", "(c)", "(d)", "i", "ii", etc. refer to steps of a method or use or assay, unless otherwise specified in this application, as described herein above or hereinafter, there is no time gap or inconsistency between the steps, i.e., the steps may be performed simultaneously or there may be a time gap of a few seconds, minutes, hours, days, weeks, months or even years between such steps.

[0016] Furthermore, ranges defined throughout this specification are inclusive of the end values ​​as well, i.e., a range of 1 to 10 means that both 1 and 10 are included within the range. For the avoidance of doubt, the applicants are entitled to any and all equivalents pursuant to applicable law.

[0017] The following sections define in more detail the various aspects of the invention claimed herein. Each aspect so defined may be combined with any other aspect or aspects, unless expressly indicated otherwise. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

[0018] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention claimed herein. Thus, appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, although they may. Furthermore, as used hereinafter, the terms "preferably," "more preferably," "even more preferably," "most preferably," and "particularly," or similar terms, may be used in conjunction with any feature without limiting alternative possibilities. Therefore, features introduced by these terms are optional features and do not limit the scope of the claims in any way.

[0019] Furthermore, as will be apparent to one skilled in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Furthermore, as will be apparent to one skilled in the art, when an embodiment described herein includes some features but not other features included in another embodiment, it is understood that a combination of features from different embodiments forms another embodiment within the scope of the inventions claimed herein. For example, in the appended claims, any one of the features may be used in combination with any one of the claimed embodiments.

[0020] Furthermore, it should be noted that the terms "at least one," "one or more," or similar expressions indicating that a feature or element may be present one or more times are typically used only once when introducing each feature or element. In most cases hereinafter, when referring to each feature or element, the expressions "at least one" or "one or more" will not be repeated, despite the fact that each feature or element may be present one or more times.

[0021] The term "yield" is defined as the amount of product obtained per unit weight of raw material and can be expressed as g of product / g of substrate. Yield can be expressed as a percentage of the theoretical yield. "Theoretical yield" is defined as the maximum amount of product that can be produced per a given amount of substrate, as determined by the stoichiometry of the metabolic pathway used to produce the product. For example, if the theoretical yield for a typical conversion of glucose to isobutanol is 0.41 g / g, a glucose to butanol yield of 0.39 g / g is expressed as 95% of the theoretical yield or 95% theoretical yield.

[0022] The term "biofuel precursor" refers to an organic molecule in which all of the carbon contained within the molecule comes from biomass and is converted thermochemically or biochemically from the feedstock to the precursor. The biofuel precursor may itself be a biofuel or may be configured to be converted, either chemically or biochemically, into a biofuel with different properties. Biofuel precursors include, but are not limited to, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, isopentanol (3-methyl-1-butanol), 3-pentanol, 2-methyl-1-butanol, or neopentanol.

[0023] The terms "alkene" and "olefin" are used interchangeably herein to refer to a non-aromatic hydrocarbon having at least one carbon-carbon double bond.

[0024] As used herein, "atmospheric carbon" refers to carbon atoms from carbon dioxide molecules that have recently (e.g., over the past few decades) been liberated into the Earth's atmosphere. Such carbon atoms are identifiable by the ratio of certain radioisotopes described herein. "Green carbon," "atmospheric carbon," "green carbon," "life cycle carbon," "non-fossil fuel-based carbon," "non-petroleum-based carbon," "atmospheric carbon," and "bio-based carbon" are used interchangeably herein.

[0025] As used herein, "fossil-derived carbon" refers to carbon derived from petrochemical products. Fossil-derived carbon is identifiable by means described herein. "Fossil fuel carbon," "fossil carbon," "pollutant carbon," "petrochemical carbon," "petroleum carbon," and "fossil-derived carbon" are used interchangeably herein.

[0026] The term "ASTM" refers to the American Society for Testing and Materials, which defines testing procedures and specifications for all petroleum products manufactured and sold commercially.

[0027] Fusel oil as used herein refers to a product formed as a by-product of alcoholic fermentation and consisting of a mixture of several alcohols consisting primarily of amyl alcohol and, depending on the refining process used, smaller amounts of propanol, n-butanol, and isobutanol.

[0028] "Renewably based" or "renewable" means that the carbon content of the biofuel precursor and subsequent products is derived from "new carbon" sources as measured by ASTM test method D6866-05, "Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis," which is incorporated herein by reference in its entirety.

[0029] method The present invention provides a process for preparing lower olefins having 4 to 7 carbon atoms, comprising: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight and / or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidative decarboxylation of the carboxylic acid to an olefin having one less carbon atom than the starting alcohol.

[0030] Process a) In step (a), the linear and / or branched C5 to C8 primary alcohol has at least one hydrogen atom bonded to a carbon atom adjacent to the one bearing the alcohol group.

[0031] A straight and / or branched chain C5 to C8 primary alcohol has at least one hydrogen atom bonded to the carbon atom adjacent to the alpha carbon atom bearing the alcohol group.

[0032] In one embodiment, the straight and / or branched chain C5-C8 primary alcohol has at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group, which is the alpha carbon atom, and the beta carbon atom (i.e., the carbon atom bonded to the first carbon atom adjacent to the one bearing the alcohol group) also has at least one hydrogen atom.

[0033] In a further embodiment, the C5 to C8 primary alcohol is obtained from a natural source or from a fermentation process.

[0034] In one embodiment, the C5 to C8 primary alcohol is obtained from fusel oil.

[0035] fusel oil Fusel oil is well known in the art and contains a mixture of light alcohols, fatty esters, terpenes, and furfural. The alcohols contained in fusel oil are primarily propanol, butanol, amyl alcohol, isoamyl alcohol, and hexanol, and optionally heavier linear alcohols such as C7 or C8 alcohols. Fusel oil, sometimes called "amyl oil" or "fusel," has different compositions depending on its origin (potato, beet, wheat, barley, etc.).

[0036] Fusel oils form a colorless or yellowish liquid with a characteristic odor. They have a density of approximately 0.83 . The boiling point of fusel oils is not constant because they are a complex mixture of substances with highly variable boiling points. Boiling begins at approximately 80°C and increases to 130-134°C. Fusel oils are insoluble in water and are typically washed with water to reduce the amount of ethanol they contain to approximately 4-5% and separated by sedimentation. Note that fusel alcohols are natural alcohols that are produced directly in distilleries and refineries through biotechnology, without any intermediate chemical processes.

[0037] Fusel oil can be obtained by several methods well known to those skilled in the art, such as direct removal and cooling in a distillation column. The removed fraction can be purified, for example, by extraction and decantation. Liquid / liquid extraction by adding water followed by decantation results in the formation of two phases. The upper phase contains mainly amyl alcohol and butyl alcohol, which are slightly soluble in water. The various fractions of fusel oil may be separated by using adsorbents, which are then regenerated. Among the adsorbents tested, granular vegetable activated carbon is preferred because it can adsorb eight times its weight of fusel oil.

[0038] In one embodiment, the fusel oil contains a mixture of straight or branched chain C5 alcohols, C4 alcohols, or C3 alcohols.

[0039] According to a preferred embodiment, the C5 branched alcohols present in the initial composition are a mixture of isoamyl alcohol and amyl alcohol, i.e. 3-methylbutan-1-ol (isoamyl alcohol) and 2-methylbutan-1-ol (amyl alcohol). According to a preferred embodiment, the initial composition comprises at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight, and even more preferably at least 70% by weight of C5 branched chain alcohols, based on the total weight of the composition.

[0040] C4 alcohols, such as butan-1-ol and 2-methylpropan-1-ol, may also be present in the initial composition. The initial composition may include one or both of these C4 alcohols.

[0041] A C3 alcohol, such as n-propanol, may also be present in the initial composition. The initial composition may include 0.01 to 20% by weight of the C3 alcohol.

[0042] The fusel oil may further contain hexanol and optionally a heavier straight chain alcohol such as a C7 or C8 alcohol.

[0043] Fusel oil is a mixture of 5% to 20% water and 60% to 95% alcohols consisting primarily of straight or branched chain alkanols containing 2 to 5 carbon atoms with impurities that can amount to up to 15% including, but not limited to, furfural, ethers, fatty acids, etc.

[0044] In one embodiment, the composition of the fusel oil is as follows: Ethanol 5-40%, 1-propanol 1-8%, 2-propanol 0-1%, 2-methylpropanol 5-15%, 1-butanol - 0-1%, 2-methyl-1-butanol 10-30%, 3-methyl-1-butanol (isoamyl alcohol) 25-70%, A combination of alkanols that represents 100%.

[0045] In one embodiment, the C5 to C8 primary alcohol is selected from 2-methyl-1-butanol (activated amyl alcohol), 3-methyl-1-butanol (isoamyl alcohol, isopentanol), n-pentanol, n-hexanol, 2-methylpentanol, n-heptanol, n-octanol, 2-ethylhexanol, or a mixture thereof.

[0046] In a preferred embodiment, the C5 to C8 primary alcohol is 3-methyl-1-butanol (isoamyl alcohol).

[0047] In one embodiment, the fusel oil derived stream comprises C5-C8 primary alcohols at a concentration in the range of 60-99 wt%, preferably in the range of 60-95 wt%, preferably in the range of 60-90 wt%, preferably in the range of 60-85 wt%, preferably in the range of 60-80 wt%, more preferably in the range of 65-80 wt%, and even more preferably in the range of 70-80 wt%.

[0048] In one embodiment, the fusel oil derived stream has a pMC of greater than 90 as measured by the method described in ASTM standard D6866 (current version is D6866-22), which defines the concept of "percent modern carbon" or pMC. Preferably, the pMC is greater than 91, preferably greater than 93, preferably greater than 95, preferably greater than 96, preferably greater than 97, more preferably greater than 98, even more preferably greater than 99.

[0049] In one embodiment, verification that a feedstock is derived from renewable raw materials can be achieved by, for example: 14 C. A feedstock shall be considered "derived from renewable sources" for purposes of this invention if the presence of carbon-14 (C-14) therein corresponds substantially (to within 6% or less) to the ASTM D6866 content of C-14 in atmospheric CO.

[0050] The C-14 content of a material can be determined by determining the decay of C-14 in the material by liquid scintillation. Such raw materials are preferably considered to be derived from renewable raw materials if the renewable raw materials have a C-14 content that exhibits a radioactive decay of 1.5 dpm / GC (decay per minute per gram of carbon) or greater, preferably 2 dpm / GC, more preferably 2.5 dpm / GC, and even more preferably 5 dpm / GC.

[0051] "Renewably based" or "renewable" means that the carbon content of biofuel precursors and subsequent products is derived from "new carbon" sources as measured by ASTM Test Method D6866, "Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis," which is incorporated herein by reference in its entirety. 14 C / 12 The C isotope ratio was measured and compared with that in standard 100% biobased materials. 14 C / 12 The C isotope ratio is compared to determine the biobased content of the sample. "Biobased materials" are organic materials whose carbon is derived from recently (on human timescales) fixed CO2 present in the atmosphere using solar energy (photosynthesis). On land, this CO2 is captured or fixed by plant life (e.g., agricultural crops or forestry materials). In the ocean, CO2 is captured or fixed by photosynthetic bacteria or phytoplankton. For example, biobased materials can be organic materials with a carbon content greater than 0. 14 C / 12 In contrast, fossil-based materials have a C isotope ratio of about 0 14 C / 12 The term "renewable" with respect to compounds such as alcohols or hydrocarbons (linear or cyclic alkanes / alkenes / alkynes, aromatics, etc.) refers to compounds that are prepared from biomass using thermochemical methods (e.g., Fischer-Tropsch catalysis), biocatalysis (e.g., fermentation), or other methods, for example, as described herein.

[0052] A small percentage of carbon atoms in atmospheric carbon dioxide are radioactive isotopes 14 C. This 14 Carbon dioxide (C) is produced when atmospheric nitrogen is hit by a neutron generated by cosmic rays, and the nitrogen loses a proton, forming carbon ( 14C), which is then immediately oxidized to carbon dioxide. The faun of 14CO2 is a small but measurable fraction of atmospheric carbon. Atmospheric carbon dioxide is processed by green plants to make organic molecules in a process known as photosynthesis. All forms of life on Earth depend on these organic molecules from green plants to produce the chemical energy that fuels growth and reproduction. Therefore, the carbon dioxide produced in the atmosphere 14 C eventually becomes part of all living organisms and their biological materials, forming biomass and the organisms that feed on it. 14 Carbon from fossil fuels, in contrast, does not have the 14C:12C ratio characteristic of renewable organic molecules derived from atmospheric carbon dioxide. Furthermore, renewable organic molecules that biodegrade to CO2 do not contribute to global warming because there is no net increase in carbon emissions to the atmosphere.

[0053] Assessment of a material's renewable-based carbon content can be performed by standard testing methods, such as using radiocarbon and isotope ratio mass spectrometry. ASTM International (formerly known as the American Society for Testing and Materials) has established a standard method for assessing the biobased content of a material. The ASTM method is referred to as ASTM-D6866.

[0054] The application of ASTM-D6866 to derive "biobased content" is based on the same concepts as radiocarbon dating, but does not use age equations. The analysis involves determining the radiocarbon ( 14 This is done by deriving a ratio of the amount of radiocarbon (C) present in the sample compared to that of a modern reference standard. This ratio is reported as a percentage in units of "pMC" (percent modern carbon). When the material being analyzed is a mixture of present-day radiocarbon and fossil carbon (containing very low levels of radiocarbon), the resulting pMC value is directly correlated to the amount of biomass material present in the sample.

[0055] The C5-C8 primary alcohols used in the present invention have a pMC value of at least greater than 90, preferably at least greater than 95, preferably at least greater than 98, more preferably at least greater than 99, and more preferably at least about 100, including all values ​​and subranges therebetween.

[0056] Step b) In step b), linear and / or branched C5-C8 primary alcohols having at least one hydrogen atom attached to the carbon atom adjacent to the one bearing the alcohol group are converted to the corresponding carboxylic acids.

[0057] A straight and / or branched chain C5 to C8 primary alcohol has at least one hydrogen atom bonded to the carbon atom adjacent to the alpha carbon atom bearing the alcohol group.

[0058] In one embodiment, the straight and / or branched chain C5-C8 primary alcohol has at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group, which is the alpha carbon atom, and the beta carbon atom (i.e., the carbon atom bonded to the first carbon atom adjacent to the one bearing the alcohol group) also has at least one hydrogen atom.

[0059] In one embodiment, the oxidation of the alcohol is carried out using an oxidizing agent selected from oxygen, hydrogen peroxide, or nitric acid.

[0060] Preferably, the oxidizing agent used in this step is oxygen or nitric acid, more preferably the oxidizing agent used is nitric acid.

[0061] Oxidation with nitric acid In one embodiment, the concentration of nitric acid used is in the range of 30% to 65% by weight, preferably in the range of 50% to 65% by weight, and more preferably in the range of 60% to 65% by weight.

[0062] In one embodiment, the weight / molar ratio of the oxidizing agent, i.e., nitric acid, to the primary alcohol is in the range of 10:1, preferably 8:1, more preferably 6:1, and even more preferably 5:1.

[0063] In one embodiment, the reaction is carried out at a temperature of less than 40°C, preferably the temperature is less than 35°C, and more preferably the temperature is less than 30°C.

[0064] In one embodiment, when fusel oil is used as the alcohol source, the reaction is carried out at 35°C.

[0065] In one embodiment, when pure alcohol is used as the reactant, the reaction is carried out at 0°C.

[0066] In one embodiment, the reaction is carried out in the presence of a solvent.

[0067] In one embodiment, the solvent is selected from aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, and also petroleum ether or halogenated hydrocarbons such as bromopropane, methylene chloride or dichloromethane, chloroform, tetrachloroethylene, aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene, aliphatic C3-C8 ethers such as 1,2-dimethoxyethane (DME), diethylene glycol dimethyl ether (diglyme), diethyl ether, dipropyl ether, methyl isobutyl ether, tert-butyl methyl ether, and tert-butyl ethyl ether, dimethoxymethane, diethoxyethanol, diisopropyl ether, methyl methyl ether, diisopropyl ... cyclohexane and cycloheptane; aliphatic C3-C6 ethers such as tetrahydrofuran (THF), tetrahydropyran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1,3,5-trioxane; short-chain ketones such as acetone, ethyl methyl ketone, and isobutyl methyl ketone.

[0068] In a preferred embodiment, the solvent is dichloromethane.

[0069] In one embodiment, the oxidation of the alcohol is carried out in the presence of nitric acid, wherein the reaction is carried out for a time period ranging from 60 minutes to 240 minutes, preferably from 60 minutes to 180 minutes, and more preferably from 60 minutes to 100 minutes.

[0070] In one embodiment, the carboxylic acid formed is isolated by distillation.

[0071] Oxidation in the presence of O In one embodiment, the oxidation reaction is carried out in the presence of a gas stream comprising O2 as an oxidant and a heterogeneous catalyst comprising a metal catalyst.

[0072] In one embodiment, the oxidation reaction is carried out in the presence of a gas stream containing O as the oxidizing agent. The oxygen can be used neat or diluted. The oxygen can be diluted with other inert gases, such as N, Ar, or CO, for example in the form of air.

[0073] In a preferred embodiment of the present invention, the oxygen is used undiluted.

[0074] In one embodiment, the oxidation reaction is carried out in the presence of an O stream having a flow rate of 1 to 10 liters / hour, preferably 2 to 8 liters / hour, more preferably 3 to 7 liters / hour, more preferably 4 to 6 liters / hour.

[0075] In a preferred embodiment, the oxidation reaction is carried out in the presence of an O2 stream having a flow rate of 5 liters / hour.

[0076] The process according to the present invention is carried out in the presence of a catalyst. The catalyst comprises at least one catalytically active metal. In the process according to the present invention, the catalytically active metal can be selected from elements selected from groups 8, 9, 10, and 11 of the periodic table (according to IUPAC nomenclature). Elements from groups 8, 9, 10, and 11 of the periodic table include iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, silver, and gold.

[0077] In a preferred embodiment, the catalytically active metal is selected from elements from groups 10 and 11 of the periodic table (according to IUPAC nomenclature).

[0078] In a preferred embodiment, the catalytically active metal is selected from an element selected from the group consisting of platinum, palladium, and gold or mixtures thereof.

[0079] In a preferred embodiment of the present invention, the catalytically active metal is platinum.

[0080] The catalytically active metal can be used in any form, for example, unsupported or on a support. The catalytically active metal can be used in unsupported form, for example, powder, mesh, sponge, foam, or net. In a preferred embodiment, the catalytically active metal is on a support.

[0081] In one embodiment, the metal catalyst is on a support selected from activated carbon, silica or alumina. Preferably, the support is selected from activated carbon.

[0082] The catalyst may optionally contain one or more so-called promoters that enhance the activity of the catalytically active metal. Examples of such promoters are bismuth (Bi), antimony (Sb), lead (Pb), cadmium (Cd), tin (Sn), tellurium (Te), cerium (Ce), selenium (Se), or thallium (Tl).

[0083] In a preferred embodiment, the catalyst comprises at least one promoter selected from the group consisting of bismuth (Bi), antimony (Sb), lead (Pb), cadmium (Cd), tin (Sn), and tellurium (Te). In a preferred embodiment, the catalyst comprises at least one promoter selected from the group consisting of bismuth (Bi), lead (Pb), and cadmium (Cd).

[0084] The promoter may be, for example, a metal, nitrate, acetate, sulfate, citrate, oxide, hydroxide, or chloride, and mixtures thereof.

[0085] When a promoter is used, the molar ratio of catalytically active metal to promoter is preferably in the range of 1:0.01 to 1:10, more preferably 1:0.5 to 1:5, and even more preferably 1:0.1 to 1:3.

[0086] The promoter may, for example, be present on the support or may be added separately to the process.

[0087] The term "on a support" encompasses that the catalytically active metal and / or promoter may be located on the exterior surface of the support and / or on the interior surface of the support. In most cases, the catalytically active metal and / or promoter will be located on both the exterior surface of the support and the interior surface of the support.

[0088] When the catalytically active metal is on a support, the catalyst comprises the catalytically active metal, the support, and optionally a promoter.

[0089] In one embodiment, the reaction is carried out at a temperature in the range of 70°C to 100°C, preferably in the range of 80°C to 100°C, preferably in the range of 80°C to 95°C, preferably in the range of 80°C to 90°C, preferably in the range of 80°C to 85°C, more preferably the temperature is about 80°C.

[0090] In one embodiment, the oxidation of the alcohol is carried out in the presence of a gas stream of O2, wherein the reaction is carried out for a time period ranging from 120 minutes to 24 hours, preferably from 120 minutes to 12 hours, more preferably from 120 minutes to 8 hours, and even more preferably from 120 minutes to 240 minutes.

[0091] Process c) In one embodiment, in step c) oxidative decarboxylation of carboxylic acids to lower olefins having C4 to C7 carbon atoms is carried out.

[0092] In one embodiment, the oxidative decarboxylation is carried out in the presence of a homogeneous catalyst, which comprises at least one metal or a salt or complex thereof and a ligand.

[0093] In one embodiment, the at least one metal is selected from nickel, palladium, or platinum. Preferably, the metal is palladium.

[0094] In one embodiment, the at least one metal or salt or complex thereof is selected from PdCl, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium [Pd(dba)], bis(dibenzylideneacetone)dipalladium [Pd(dba)], palladium acetate, dichloro(1,5-cyclooctadiene)palladium, and bis[cinnamylpalladium(II)] chloride.

[0095] Preferably, the metal salt is PdCl2.

[0096] In one embodiment, the homogeneous catalyst is 5-(di-tert-butylphosphino)-1′,3′,5′-triphenyl-1′H-1,4′-bipyrazole, bis(2-methyl-2-propanyl)(2′,4′,6′-triisopropyl-3,6-dimethoxy-2-biphenylyl)phosphine, dicyclohexyl(2′,4′,6′-triisopropyl-3,6-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine, bis(2-methyl-2-propanyl)(2′,4′,6′-triisopropyl-2-biphenylyl)phosphine, di-(1-adamantyl)phosphine, (R)-1-[(SP)-2-(diphenylphosphino)ferrocenyl]ethyldicyclohexylphosphine, dicyclohexyl-[2-[2,6-di(propan-2-yloxy)phenyl]phenyl]phosphane, bis[5-(di(1-adamantyl)phosphino)-1',3',5'-triphenyl-1'H-[1,4']bipyrazoline trimethylphosphine, triethylphosphine, tripropylphosphine, triisopropylphosphine, tributylphosphine, tricyclohexylphosphine, trimethylphosphine, triethylphosphite, tripropylphosphite, triisopropylphosphine, tributylphosphine, tricyclohexylphosphine, triphenylphosphine, tri(o-tolyl)phosphine, triisopropylphosphine, tricyclohexylphosphine, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) , 1,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)-ethane, 1,2-bis(dipropylphosphino)ethane, 4,5-bis(diphenylphosphino)-9,9-dimethyl-xanthene (xantphos), 1,1'-bis(diphenylphosphino)ferrocene (dppf), bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos], 1,2-bis(diisopropylphosphino)ethane, 1,2-bis-(dibutylphosphino)ethane, 1,2-bis(dicyclohexylphosphino)ethane, 1,3-bis(diisopropyl-phosphino)propane, 1,3-bis(dicyclohexylphosphino)propane, 1,4-bis(diisopropyl-phosphino)butane, 1,4-bis(dicyclohexylphosphino)butane, 1,4-bis(diphenylphosphino)butane (bppb), 2,4-bis(dicyclohexylphosphino)pentane and 1,1'-bis(diphenylphosphino)ferrocene (dppf), triphenylphosphine (PPh3), Xantphos ((9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)), SPANphos (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane)), and 2,2'-bis-(diphenylphosphino)-benzophenone.

[0097] Preferably, the ligand is selected from bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos], triphenylphosphine (PPh3), Xantphos ((9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)), SPANphos (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane)), 2,2'-bis-(diphenylphosphino)-benzophenone.

[0098] More preferably, the ligand is bis(2-(diphenyl-phosphino)phenyl) ether [DPE-phos].

[0099] In one embodiment, the homogeneous catalyst is used at a concentration of less than 5 mol %, preferably less than 3 mol %, more preferably less than 2 mol %.

[0100] In one embodiment, the catalyst is used at a concentration in the range of 0.1 mol % to 2 mol % based on the carboxylic acid in step (b).

[0101] In one embodiment, the molar ratio of ligand to metal catalyst or its salt or complex ranges from 5:1 to 1:1, preferably the ratio of ligand to metal catalyst or its salt or complex is 2:1.

[0102] In one embodiment, step c) is carried out in the presence of an acid anhydride.

[0103] In one embodiment, the decarboxylation of the acid to a lower olefin having C4 to C7 carbon atoms in step c) is carried out in the presence of a carboxylic acid anhydride different from the coupling product of the carboxylic acid obtained in step b).

[0104] In another embodiment, the acid anhydride is selected from acetic anhydride, propanoic anhydride, butanoic anhydride, or maleic anhydride. Preferably, the acid anhydride is acetic anhydride.

[0105] In one embodiment, step (c) is carried out at a reaction temperature below 150°C, preferably below 145°C, preferably in the range of 130°C to 150°C, more preferably in the range of 130°C to 145°C.

[0106] In a further embodiment, step c) is carried out for a time period in the range of 60 minutes to 300 minutes, preferably in the range of 100 minutes to 300 minutes, more preferably in the range of 120 minutes to 240 minutes, more preferably in the range of 60 minutes to 240 minutes.

[0107] In one embodiment, the olefin having C4 to C7 carbon atoms is selected from 1-butene, isobutylene, 1-pentene, isopentene, 1-hexene, 2-hexene, 3-hexene, 4-methyl-1-pentene, preferably the olefin is isobutylene.

[0108] In one embodiment of the present invention, the method comprises: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight and / or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidative decarboxylation of the carboxylic acid to an olefin having one less carbon atom than the starting alcohol; A linear or branched C5-C8 alcohol at a concentration of 60 to 99 weight percent is converted to at least one lower hydrocarbon having C4 to C7 carbon atoms in a yield of at least about 80 weight percent of the maximum theoretical molar yield.

[0109] In one embodiment of the present invention, the method comprises: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight and / or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing a primary alcohol to the corresponding carboxylic acid in the presence of an oxidizing agent selected from nitric acid or O2, wherein the oxidation of the alcohol is carried out in the presence of a heterogeneous material comprising platinum; c) oxidative decarboxylation of the carboxylic acid to an olefin having one less carbon atom than the starting alcohol, which is carried out in the presence of a homogeneous catalyst at a concentration of less than 5 mol %, preferably less than 3 mol %, more preferably less than 2 mol %, A linear or branched C5 to C8 alcohol, which is isoamyl alcohol at a concentration of 60 to 99 weight percent, is converted to at least one lower hydrocarbon having C4 to C7 carbon atoms, which is isobutylene, in a yield of at least about 80 weight percent of the maximum theoretical molar yield.

[0110] Advantages of the Invention 1. The process according to the invention makes it possible to prepare olefins in high yield and selectivity under mild conditions of both temperature and pressure, while requiring only moderate to small amounts of catalyst. 2. The process can be carried out using no or little organic solvents, thus avoiding or minimizing environmentally problematic waste streams. 3. A further advantage of the process of the present invention is that the desired olefin is obtained in high concentration in the reaction mixture, thus minimizing downstream isolation steps. 4. The process of the present invention allows for the formation of olefins in comparable yield and purity regardless of the source of the primary alcohol used as the starting material (pure primary alcohol or alcohol isolated from fusel oil). Thus, impurities in the starting material do not interfere with the yield and purity of the final product (in this case, the olefin). 5. The process according to the present invention uses readily available reagents, thereby reducing the overall cost of the process, thereby making it an industrially viable process that can be easily scaled up. 6. The process according to the invention uses 3-methyl-1-butanol from fusel oil as a starting material, in combination with oxidation of the alcohol to 3-methylbutanoic acid and oxidative decarboxylation to isobutene. While the individual steps are known reactions, they have not been described for this particular substrate and have not been combined as a means to obtain an olefin (isobutene) with a pMC of greater than 90%, and therefore can be considered an invention. 7. The resulting olefin (isobutene) will also have a pMC value of greater than 90, which can be deduced from the fact that the input stream comprising linear or branched C5-C8 primary alcohols has a pMC value of greater than 90 (obtained in natural sources, i.e. fusel oil).

[0111] Embodiment Below, a list of embodiments is provided to further illustrate the present disclosure, but is not intended to limit the disclosure to the specific embodiments listed below.

[0112] 1. A process for preparing lower olefins having 4 to 7 carbon atoms, comprising: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight and / or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidatively decarboxylating the carboxylic acid to an olefin having one less carbon atom than the starting alcohol.

[0113] 2. The method of embodiment 1, wherein the stream comprising straight and / or branched chain C5-C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing the alcohol group has a pMC of at least greater than 90, preferably a pMC value of at least greater than 95, preferably a pMC value of at least greater than 98, more preferably a pMC value of at least 99, more preferably a pMC value of at least about 100, including all values ​​and subranges therebetween, when measured by the method set forth in ASTM Standard D6866.

[0114] 3. The method of embodiment 2, wherein the stream comprising straight or branched chain C5-C8 primary alcohols having at least one hydrogen atom attached to a carbon atom adjacent to one bearing the alcohol group is obtained from a natural source.

[0115] 4. The method of embodiment 2, wherein the stream comprising linear or branched C5-C8 primary alcohols having at least one hydrogen atom attached to a carbon atom adjacent to one bearing an alcohol group is obtained from a fermentation process.

[0116] 5. The method of embodiment 1, wherein the stream comprising straight and / or branched chain C5 to C8 primary alcohols has at least one hydrogen atom bonded to a carbon atom adjacent to one bearing the alcohol group, the carbon atom being the alpha carbon atom.

[0117] 6. The method of embodiment 5, wherein the stream comprising straight-chain and / or branched-chain C5-C8 primary alcohols has at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group, which is the alpha carbon atom, and the beta carbon atom (i.e., the carbon atom bonded to the first carbon atom adjacent to the one bearing the alcohol group) also has at least one hydrogen atom.

[0118] 7. The method of any one of embodiments 1 to 6, wherein the linear or branched C5-C8 primary alcohol having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group is selected from 2-methyl-1-butanol (activated amyl alcohol), 3-methylbutan-1-ol (isoamyl alcohol, isopentanol), n-pentanol, n-hexanol, 2-methylpentanol, n-heptanol, n-octanol, 2-ethylhexanol.

[0119] 8. The method of any one of embodiments 1 to 7, wherein the linear or branched C5-C8 primary alcohol having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing the alcohol group is 3-methylbutan-1-ol (isoamyl alcohol, isopentanol).

[0120] 9. The method of any one of embodiments 1 to 8, wherein the stream comprises linear and / or branched C5-C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, in a concentration in the range of 60 to 99 wt%, preferably in the range of 60 to 95 wt%, preferably in the range of 60 to 90 wt%, preferably in the range of 60 to 85 wt%, preferably in the range of 60 to 80 wt%, more preferably in the range of 65 to 80 wt%, and even more preferably in the range of 70 to 80 wt%.

[0121] 10. The method of embodiment 1, wherein in step (b), the oxidation of the primary alcohol is carried out using an oxidizing agent selected from O2, H2O2, or nitric acid.

[0122] 11. The method of embodiment 10, wherein in step (b), the oxidation of the primary alcohol is carried out using nitric acid.

[0123] 12. The method of embodiment 11, wherein in step (b), the oxidation of the primary alcohol is carried out using nitric acid at a concentration in the range of 30% to 65% by weight, preferably in the range of 50% to 65% by weight, and more preferably in the range of 60% to 65% by weight.

[0124] 13. The method of embodiment 10 or 11, wherein in step (b), the oxidation of the primary alcohol is carried out at a reaction temperature of less than 40°C, preferably, the temperature is less than 35°C, and more preferably, the temperature is less than 30°C.

[0125] 14. The method of embodiment 10 or 11, wherein in step (b), the oxidation of the primary alcohol is carried out in the presence of nitric acid, and wherein the reaction is carried out for a time in the range of 60 minutes to 240 minutes, preferably in the range of 60 minutes to 180 minutes, and more preferably in the range of 60 minutes to 100 minutes.

[0126] 15. The method according to embodiment 10, wherein in step (b), the oxidation of the primary alcohol is carried out in the presence of a gas stream containing O2 as an oxidant, having a flow rate of 1 to 10 liters / hour, preferably 2 to 8 liters / hour, more preferably 3 to 7 liters / hour, more preferably 4 to 6 liters / hour, and a heterogeneous material comprising a metal catalyst selected from the group selected from platinum, palladium, gold, or a mixture thereof.

[0127] 16. The method of embodiment 15, wherein in step (b), the oxidation of the alcohol is carried out in the presence of a heterogeneous metal comprising palladium.

[0128] 17. The method of embodiment 15 or 16, wherein the metal catalyst is supported on an inert support, the support being selected from activated carbon, silica, or alumina, optionally doped with bismuth cadmium or lead bismuth.

[0129] 18. The method of any one of embodiments 15 to 17, wherein the oxidation of the alcohol is carried out at a reaction temperature in the range of 80°C to 100°C, preferably 80°C to 95°C, preferably in the range of 80°C to 90°C, preferably in the range of 80°C to 85°C, more preferably the temperature is about 80°C.

[0130] 19. The method of any one of embodiments 15 to 17, wherein the oxidation of the primary alcohol is carried out in the presence of a gas stream of O2, wherein the reaction is carried out for a time in the range of 120 minutes to 24 hours, preferably in the range of 120 minutes to 12 hours, more preferably in the range of 120 minutes to 8 hours, and even more preferably in the range of 120 minutes to 240 minutes.

[0131] 20. The method of embodiment 1, wherein in step (c), the oxidative decarboxylation of the acid to a lower olefin having C4 to C7 carbon atoms is carried out in the presence of a homogeneous catalyst.

[0132] 21. The method of embodiment 20, wherein the homogeneous catalyst comprises at least one metal or a salt or complex thereof, and a ligand.

[0133] 22. The method of embodiment 21, wherein the at least one metal is selected from nickel, palladium, or platinum.

[0134] 23. The method of embodiment 22, wherein at least one metal is palladium.

[0135] 24. The method of any one of embodiments 21-23, wherein the at least one metal or salt or complex thereof is selected from PdCl2, tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium [Pd2(dba)3], bis(dibenzylideneacetone)dipalladium [Pd(dba)2], palladium acetate, dichloro(1,5-cyclooctadiene)palladium, and bis[cinnamylpalladium(II)] chloride.

[0136] 25. The homogeneous catalyst is 5-(di-tert-butylphosphino)-1',3',5'-triphenyl-1'H-1,4'-bipyrazole, bis(2-methyl-2-propanyl)(2',4',6'-triisopropyl-3,6-dimethoxy-2-biphenylyl)phosphine, dicyclohexyl(2',4',6'-triisopropyl-3,6-dimethoxy-[1,1'-biphenyl]-2-yl)phosphine, bis(2-methyl-2-propanyl)(2',4',6'-triisopropyl-2-biphenylyl)phosphine, di-(1-adamantyl)- 2-morpholinophenylphosphine, tributylphosphine, butyldi-1-adamantylphosphine, (5-diphenylphosphanyl-9,9-dimethylxanthen-4-yl)-diphenylphosphine, (R)-1-[(SP)-2-(diphenylphosphino)ferrocenyl]ethyldicyclohexylphosphine, dicyclohexyl-[2-[2,6-di(propan-2-yloxy)phenyl]phenyl]phosphane, bis[5-(di(1-adamantyl)phosphino)-1',3',5'-triphenyl-1'H-[1,4']bipyrazole, Trimethylphosphine, triethylphosphine, tripropylphosphine, triisopropylphosphine, tributylphosphine, tricyclohexylphosphine, trimethylphosphine, triethylphosphite, tripropylphosphite, triisopropylphosphite, tributylphosphite, tricyclohexylphosphine, triphenylphosphine, tri(o-tolyl)phosphine, triisopropylphosphine, tricyclohexylphosphine, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), 1 ,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)-ethane, 1,2-bis(dipropylphosphino)ethane, 4,5-bis(diphenylphosphino)-9,9-dimethyl-xanthene (xantphos), 1,1'-bis(diphenylphosphino)ferrocene (dppf), bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos], 1,2-bis(diisopropylphosphino)ethane, 1,2-bis-(dibutylphosphino)ethane, 1,2-bis(dicyclohexylphosphino)ethane, 1,3-bis(diisopropyl-phosphino)propane, 1,3-bis(dicyclohexylphosphino)propane, 1,4-bis(diisopropyl-phosphino)butane, 1,4-bis(dicyclohexylphosphino)butane, 1,4-bis(diphenylphosphino)butane (bppb), 2,4-bis(dicyclohexylphosphino)pentane and 1,1'-bis(diphenylphosphino)ferrocene (dppf), triphenylphosphine ( PPh3), Xantphos ((9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)), SPANphos (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane)), and 2,2'-bis-(diphenylphosphino)-benzophenone, 22. The method according to embodiment 21, wherein the ligand is selected from bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos], triphenylphosphine (PPh3), Xantphos ((9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)), SPANphos (4,4,4',4',6,6'-hexamethyl-3,3',4,4'-tetrahydro-2,2'-spirobi[[1]benzopyran]-8,8'-diyl)bis(diphenylphosphane)), 2,2'-bis-(diphenylphosphino)-benzophenone, more preferably the ligand is bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos].

[0137] 26. The method of any one of embodiments 20 to 25, wherein in step (c), the homogeneous catalyst is used at a concentration of less than 5 mol %, preferably less than 3 mol %, more preferably less than 2 mol %.

[0138] 27. The method of any one of embodiments 20 to 25, wherein in step (c), the molar ratio of ligand to metal catalyst or a salt or complex thereof is 5:1 or 3:1, preferably 2:1.

[0139] 28. The method according to any one of embodiments 20 to 25, wherein in step (c), the decarboxylation of the acid to a lower hydrocarbon having C4 to C7 carbon atoms is carried out in the presence of a carboxylic acid anhydride (acid anhydride) different from the coupling product of the carboxylic acid obtained in step b).

[0140] 29. The method of embodiment 26, wherein the acid anhydride is selected from acetic anhydride, propanoic anhydride, butanoic anhydride, or maleic anhydride.

[0141] 30. The method of embodiment 27, wherein the acid anhydride is acetic anhydride.

[0142] 31. The method of any one of embodiments 20 to 29, wherein in step (c), the decarboxylation of the acids to lower hydrocarbons having C4 to C7 carbon atoms is carried out at a reaction temperature of less than 150°C, preferably less than 145°C, preferably in the range of 130°C to 150°C, more preferably in the range of 130°C to 145°C.

[0143] 32. The method of any one of embodiments 20 to 30, wherein in step (c), the decarboxylation of the acids to lower hydrocarbons having C4 to C7 carbon atoms is carried out for a time period ranging from 60 minutes to 300 minutes, preferably from 100 minutes to 300 minutes, more preferably from 120 minutes to 240 minutes, more preferably from 60 minutes to 240 minutes.

[0144] 33. The method of any one of embodiments 20 to 31, wherein the lower hydrocarbon having C4 to C7 carbon atoms is selected from 1-butene, isobutylene, 1-pentene, isopentene, 1-hexene, 2-hexene, 3-hexene, 4-methyl-1-pentene.

[0145] 34. The method of embodiment 33, wherein the lower hydrocarbon having C4 to C7 carbon atoms is isobutylene.

[0146] 35. The method of any one of embodiments 1 to 33, wherein a linear or branched C5 to C8 primary alcohol having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group is converted, at a concentration of 60 to 99 wt%, to at least one lower hydrocarbon having C4 to C7 carbon atoms in a yield of at least about 80 wt% of the maximum theoretical molar yield.

[0147] 36. How to: a) feeding a stream containing, in a concentration of 60 to 99 wt. % straight or branched chain C5 to C8 primary alcohols having at least one hydrogen atom bonded to a carbon atom adjacent to one bearing an alcohol group, into a reactor; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidative decarboxylation of the carboxylic acid to an olefin having one less carbon atom than the starting alcohol; 36. The method of any one of embodiments 1 to 35, wherein a linear or branched C5 to C8 primary alcohol at a concentration of 60 to 99 wt. % is converted to at least one lower hydrocarbon having C4 to C7 carbon atoms in a yield of at least about 80 wt. % of the maximum theoretical molar yield. [Example]

[0148] The present invention is further illustrated by the following non-limiting examples. material Isoamyl alcohol isolated from crude / fusel oil was sourced from Crop Energies AG. The composition of the fusel oil used was as follows: Ethanol 2.15% Isobutanol 13.38% Butanol 0.98% Isoamyl alcohol 77.23% 2-methylbutanol 3.55% Furfural 0.21% Hexanol 0.21% Isoamyl acetate 0.13% Benzaldehyde 0.01% Ethylhexanoate 0.09% Phenylethanol 0.20% Phenylethyl acetate 0.11% Ethyl decanoate 0.10% Ethyl laurate 0.05% Hexanoic acid ethyl ester 0.31% Unknown impurities 1.29%

[0149] Example 1: Oxidation of pure isoamyl alcohol with O [ka] Isoamyl alcohol (10 g) was mixed with water (90 g). The catalyst Pt / C (3 g, 5 wt. % Pt on C, 58 wt. % water) was added and the mixture was stirred at 80° C. under a dioxygen atmosphere for 24 hours. After cooling to ambient temperature, the mixture was diluted with ethyl acetate, filtered, and the aqueous phase was extracted with ethyl acetate. The solvent was removed in vacuo. Yield: 85%

[0150] Example 2: Oxidation of pure isoamyl alcohol with HNO Nitric acid (55 g, 65%) was cooled to 0°C using an ice bath. With stirring under nitrogen, isoamyl alcohol (10 g) was added dropwise over 45 minutes. After the addition was complete, water (50 mL) was added and the mixture was stirred for 10 minutes. The biphasic mixture was diluted with dichloromethane (100 mL) and stirred for 30 minutes. The phases were separated and the organic phase was dried over sodium sulfate. The product isovaleric acid was isolated by distillation (oil bath at 190°C, maximum temperature 120°C). Yield: 94%

[0151] Example 3: Oxidation of fusel oil (containing 70% isoamyl alcohol) with HNO Nitric acid (57 g, 65%) was adjusted to 35°C in an oil batch. With stirring under nitrogen, fusel oil (14.5 g containing 70% isoamyl alcohol) was added dropwise over 45 minutes. After the addition was complete, water (50 mL) was added and the mixture was stirred for 10 minutes. The biphasic mixture was diluted with dichloromethane (100 mL) and water (100 mL) and stirred for 30 minutes. The phases were separated and the organic phase was dried over sodium sulfate. The product isovaleric acid was isolated by distillation (oil bath at 200°C, maximum temperature 170°C). Yield: 84%

[0152] Example 4: Decarboxylation of isovaleric acid to isobutylene Isovaleric acid (1.87 g) was mixed with PdCl2 (1.76 mol%) and dis[(diphenylphosphino)phenyl]ether (DPE-Phos, 3.53 mol%) under a nitrogen atmosphere. DMPU (N,N'-dimethylpropylene urea, 36 g) was added, and acetic anhydride (2.53 g) was slowly added with stirring. After stirring at ambient temperature for 15 minutes, the reaction mixture was heated to 140 °C for 4 hours. With heating, the PdCl2 completely dissolved, as indicated by the yellow coloration of the solution. The completion of the reaction was indicated by the red coloration of the reaction mixture. The isobutylene produced was collected using a gas collector for analysis and condensation in toluene. Yield: 85-87%

[0153] Example 5: Oxidation of pure 2-methyl-1-butanol with HNO [ka] Nitric acid (5.5 g, 65%) was cooled to 0°C using an ice bath. With stirring under nitrogen, 2-methyl-1-butanol (1 g) was added dropwise over 15 minutes. After the addition was complete, water (50 mL) was added and the mixture was stirred for 10 minutes. The biphasic mixture was diluted with dichloromethane (15 mL) and stirred for 30 minutes. The phases were separated and the organic phase was dried over sodium sulfate. The product, 2-methyl-1-butanoic acid, was isolated by distillation (oil bath at 190°C, maximum temperature 120°C). Yield: 90%.

[0154] Example 6: Decarboxylation of 2-methyl-1-butanoic acid to butylene isomers 2-Methyl-1-butanoic acid (0.5 g) obtained in Example 5 was mixed with PdCl2 (1.76 mol%) and dis[(diphenylphosphino)phenyl]ether (DPE-Phos, 3.53 mol%) under a nitrogen atmosphere. DMPU (N,N'-dimethylpropylene urea, 9.5 g) was added, and acetic anhydride (0.68 g) was slowly added with stirring. After stirring at ambient temperature for 15 minutes, the reaction mixture was heated to 140 °C for 4 hours. With heating, PdCl2 completely dissolved, as indicated by the yellow coloration of the solution. The completion of the reaction was indicated by the red coloration of the reaction mixture. The butylene isomers produced were collected using a gas collector for analysis and condensation in toluene. Yield: 81%, containing 1-butylene, cis-butylene, and trans-butylene in a 6:2:1 ratio.

[0155] [Table 1]

Claims

1. 1. A process for preparing lower olefins having 4 to 7 carbon atoms, comprising: a) in a concentration of 60 to 99% by weight, linear and / or branched C having at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group; ５ ~C ８ providing a stream comprising a primary alcohol to a reaction vessel; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidatively decarboxylating the carboxylic acid to an olefin having one less carbon atom than the starting alcohol.

2. A straight and / or branched chain C having at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group ５ ~C ８ 10. The method of claim 1, wherein the stream comprising a primary alcohol has a pMC greater than 90 as measured by the method set forth in ASTM standard D6866.

3. A straight and / or branched chain C having at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group ５ ~C ８ 3. The method of claim 2, wherein the stream comprising a primary alcohol is obtained from a natural source or from a fermentation process.

4. The straight or branched chain C has at least one hydrogen atom bonded to the carbon atom adjacent to the one having the alcohol group. ５ ~C ８ 4. The method according to claim 1, wherein the primary alcohol is selected from 2-methyl-1-butanol (activated amyl alcohol), 3-methylbutan-1-ol (isoamyl alcohol, isopentanol), n-pentanol, n-hexanol, 2-methylpentanol, n-heptanol, n-octanol, or 2-ethylhexanol.

5. The straight or branched chain C has at least one hydrogen atom bonded to the carbon atom adjacent to the one having the alcohol group. ５ ~C ８ 5. The method according to claim 1, wherein the primary alcohol is 3-methylbutan-1-ol (isoamyl alcohol, isopentanol).

6. In step (b), the oxidation of the primary alcohol is ２ , H ２ O ２ 10. The method of claim 1, wherein the method is carried out using an oxidizing agent selected from:

7. 7. The method of claim 6, wherein in step (b), the oxidation of the primary alcohol is carried out using nitric acid at a concentration in the range of 40 to 65% by weight.

8. In step (b), the oxidation of the primary alcohol is carried out using O as the oxidizing agent. ２ 7. The process of claim 6, wherein the process is carried out in the presence of a gas stream comprising: and a heterogeneous catalyst comprising a metal catalyst selected from platinum, palladium, gold, or mixtures thereof.

9. 9. The method of claim 8, wherein in step (b), the oxidation of the primary alcohol is carried out in the presence of platinum.

10. In step (c), the acid ４ ~C ７ 2. The process of claim 1, wherein the oxidative decarboxylation to lower olefins having carbon atoms is carried out in the presence of a homogeneous catalyst.

11. 11. The method of claim 10, wherein the homogeneous catalyst comprises at least one metal or a salt or complex thereof, and a ligand.

12. The method of claim 11 , wherein the at least one metal is selected from nickel, palladium, or platinum.

13. The at least one metal or a salt or complex thereof is PdCl ２ , tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, tris(dibenzylideneacetone)dipalladium [Pd ２ (dba) ３ ], bis(dibenzylideneacetone)dipalladium [Pd(dba)] ２ 13. The method of claim 11 or 12, wherein the palladium compound is selected from the group consisting of palladium acetate, dichloro(1,5-cyclooctadiene)palladium, and bis[cinnamylpalladium(II)]chloride.

14. The homogeneous catalyst is selected from the group consisting of 5-(di-tert-butylphosphino)-1',3',5'-triphenyl-1'H-1,4'-bipyrazole, bis(2-methyl-2-propanyl)(2',4',6'-triisopropyl-3,6-dimethoxy-2-biphenylyl)phosphine, dicyclohexyl(2',4',6'-triisopropyl-3,6-dimethoxy-[1,1'-biphenyl]-2-yl)phosphine, bis(2-methyl-2-propanyl)(2',4',6'-triisopropyl-2-biphenylyl)phosphine, di-(1-adamantyl)- 2-morpholinophenylphosphine, tributylphosphine, butyldi-1-adamantylphosphine, (5-diphenylphosphanyl-9,9-dimethylxanthen-4-yl)-diphenylphosphine, (R)-1-[(SP)-2-(diphenylphosphino)ferrocenyl]ethyldicyclohexylphosphine, dicyclohexyl-[2-[2,6-di(propan-2-yloxy)phenyl]phenyl]phosphane, bis[5-(di(1-adamantyl)phosphino)-1',3',5'-triphenyl-1'H-[1,4']bipyrazole, Trimethylphosphine, triethylphosphine, tripropylphosphine, triisopropylphosphine, tributylphosphine, tricyclohexylphosphine, trimethylphosphine, triethylphosphite, tripropylphosphite, triisopropylphosphine, tributylphosphine, tricyclohexylphosphine, triphenylphosphine, tri(o-tolyl)phosphine, triisopropylphosphine, tricyclohexylphosphine, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP), 1 ,2-bis(dimethylphosphino)ethane, 1,2-bis(diethylphosphino)-ethane, 1,2-bis(dipropylphosphino)ethane, 4,5-bis(diphenylphosphino)-9,9-dimethyl-xanthene (xantphos), 1,1'-bis(diphenylphosphino)ferrocene (dppf), bis(2-(diphenyl-phosphino)phenyl)ether [DPE-phos], 1,2-bis(diisopropylphosphino)ethane, 1,2-bis-(dibutylphosphino)ethane, 1,2-bis(dicyclohexylphosphino)ethane, 1,12. The method of claim 11, comprising a ligand selected from 3-bis(diisopropyl-phosphino)propane, 1,3-bis(dicyclohexylphosphino)propane, 1,4-bis(diisopropyl-phosphino)butane, 1,4-bis(dicyclohexylphosphino)butane, 1,4-bis(diphenylphosphino)butane (bppb), 2,4-bis(dicyclohexylphosphino)pentane, or 1,1′-bis(diphenylphosphino)ferrocene (dppf).

15. In step (c), C ４ ~C ７ 15. The process according to any one of claims 10 to 14, wherein the decarboxylation of the acid to a lower olefin having carbon atoms is carried out in the presence of a carboxylic acid anhydride different from the coupling product of the carboxylic acid obtained in step b).

16. 16. The method of claim 15, wherein the carboxylic acid anhydride is selected from acetic anhydride, propanoic anhydride, butanoic anhydride, or maleic anhydride.

17. 15. The process according to any one of claims 10 to 14, wherein the catalyst is used at a concentration ranging from 0.1 mol % to 2 mol % based on the carboxylic acid in step (b).

18. C ４ ~C ７ 18. The process of any one of claims 1 to 17, wherein the lower olefin having carbon atoms is selected from 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, hexene, 2-hexene, 3-hexene, or 4-methyl-1-pentene.

19. A straight and / or branched chain C having at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group ５ ~C ８ The stream containing primary alcohols is C ４ ~C ７ 19. The process of any one of claims 1 to 18, wherein the conversion to at least one lower olefin having carbon atoms is at least about 80% by weight of the maximum theoretical molar yield.

20. The method comprising: a) in a concentration of 60 to 99% by weight, linear and / or branched C having at least one hydrogen atom bonded to the carbon atom adjacent to the one bearing the alcohol group; ５ ~C ８ providing a stream comprising a primary alcohol to a reaction vessel; b) oxidizing the primary alcohol to the corresponding carboxylic acid; c) oxidatively decarboxylating the carboxylic acid to an olefin having one less carbon atom than the starting alcohol; Straight or branched chain C ５ ~C ８ The primary alcohol is C ４ ~C ７ 19. The process of any one of claims 1 to 18, wherein the conversion to at least one lower olefin having carbon atoms is at least about 80% by weight of the maximum theoretical molar yield.

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