Process for dehydrating alcohols to prepare ethers

Abstract

A method for dehydrating C2+ alcohols to ether products in the presence of a catalyst and a co-catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite with a 3-dimensional framework structure, and the co-catalyst is one or more organic carbonyl compounds or derivatives thereof, and wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

Description

[0001] The present invention relates generally to dehydration processes and, more particularly, to a process for the dehydration of alcohols to prepare ethers in the presence of an aluminosilicate zeolite catalyst and a promoter compound.

[0002] Ethers are widely used chemicals and are produced on an industrial scale worldwide. Methods for the preparation of ethers are known in the art; for example, the preparation of ethers by dehydrating alcohols using solid acid catalysts is known in the art, such as the dehydration of methanol to dimethyl ether or ethanol to diethyl ether using zeolites (e.g., ZSM-5) is known in the art.

[0003] The applicant has now discovered that organic carbonyl compounds or derivatives thereof, in particular compounds selected from the following, have a beneficial effect on the rate of dehydration of C2+ alcohols carried out in the presence of an aluminosilicate zeolite catalyst, which is a mesoporous zeolite having a 3-dimensional framework structure:

[0004] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0005] (ii) acetal derivatives of aldehydes of formula I;

[0006] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0007] (iv) ketal derivatives of ketones of formula II;

[0008] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0009] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group.

[0010] Therefore, the present invention provides a method for dehydrating C2+ alcohols to ether products in the presence of a catalyst and a co-catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more organic carbonyl compounds or their derivatives, wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0011] According to a specific embodiment, the present invention provides a method for dehydrating C2+ alcohols to ether products in the presence of a catalyst and a co-catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more compounds selected from the following:

[0012] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0013] (ii) acetal derivatives of aldehydes of formula I;

[0014] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0015] (iv) ketal derivatives of ketones of formula II;

[0016] (v) Formula R E1 CO2RE2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0017] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group,

[0018] And wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0019] Advantageously, the cocatalyst of the present invention allows for improved productivity of ether products in dehydration reactions of C2+ alcohols carried out in the presence of an aluminosilicate zeolite catalyst, which is a medium-porous zeolite having a 3-dimensional framework structure.

[0020] In addition, according to the present invention, a method for improving the productivity of ether products in a process for dehydrating C2+ alcohols in the presence of a catalyst and a co-catalyst is provided, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more organic carbonyl compounds or derivatives thereof, and wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0021] According to a particular embodiment of the present invention, there is provided a method for improving the productivity of ether products in a process for dehydrating C2+ alcohols in the presence of a catalyst and a co-catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a mesoporous zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more compounds selected from the group consisting of:

[0022] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0023] (ii) acetal derivatives of aldehydes of formula I;

[0024] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0025] (iv) ketal derivatives of ketones of formula II;

[0026] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0027] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group,

[0028] And wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0029] Still further according to the present invention, there is provided the use of a co-catalyst in a method for catalytically dehydrating C2+ alcohols to ether products to improve the production capacity of the ether products, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-porous zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more organic carbonyl compounds or derivatives thereof, and wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0030] Still further according to a specific embodiment of the present invention, there is provided the use of a co-catalyst in a method for catalytically dehydrating a C2+ alcohol to an ether product to improve the productivity of the ether product, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a mesoporous zeolite having a 3-dimensional framework structure, and the co-catalyst is one or more compounds selected from the following:

[0031] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0032] (ii) acetal derivatives of aldehydes of formula I;

[0033] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0034] (iv) ketal derivatives of ketones of formula II;

[0035] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0036] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group,

[0037] And wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

[0038] A further aspect of the present invention provides a method for dehydrating C2+ alcohols to ether products in the presence of a catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite having a 3-dimensional framework structure, and wherein before using the catalyst in the dehydration method, the catalyst has been impregnated with a co-catalyst, the co-catalyst being an organic carbonyl compound or a derivative thereof.

[0039] According to a particular aspect of the present invention, there is provided a process for dehydrating C2+ alcohols to ether products in the presence of a catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst being a mesoporous zeolite having a 3-dimensional framework structure, and wherein prior to using the catalyst in the dehydration process, the catalyst has been impregnated with a promoter selected from:

[0040] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0041] (ii) acetal derivatives of aldehydes of formula I;

[0042] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0043] (iv) ketal derivatives of ketones of formula II;

[0044] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11an alkyl group, or an optionally substituted aromatic group; and

[0045] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group.

[0046] The catalytic dehydration reaction of alcohol to ether can be represented by the following reaction formula: x OH + R y OH ⇌ R x OR y + Water, of which R x and R y Can be the same or different.

[0047] In the present invention, the C2+ alcohol to be dehydrated can be any C2+ alcohol that can form an ether by dehydration. In some or all embodiments, the C2+ alcohol is a monovalent C2+ alcohol. Typically, the C2+ alcohol is a primary alcohol.

[0048] In some or all embodiments, the C2+ alcohol is a C2-C 12 Alcohol, preferably C2-C 12 Monohydric alcohol.

[0049] In some or all embodiments of the present invention, the C2+ alcohol contains only unsubstituted hydrocarbon groups and hydroxyl groups, preferably the C2+ alcohol contains unsubstituted C2-C 12 Hydrocarbon and hydroxyl groups.

[0050] C2-C 12 The hydrocarbon group can be any suitable saturated or unsaturated, linear, branched or cyclic hydrocarbon group containing 2-12 carbon atoms, preferably 2-10 carbon atoms, more preferably 2-8 carbon atoms, for example 2-6 carbon atoms. In some or all embodiments, the C2+ alcohol contains a C2-C6 alkyl group and a hydroxyl group.

[0051] In some or all embodiments, the C2+ alcohol to be dehydrated is a primary alcohol comprising a C2-C6 alkyl group and a hydroxyl group, such as one or more alcohols selected from ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol. In some or all embodiments, the C2+ alcohol to be dehydrated is a primary alcohol comprising a linear C2-C6 alkyl group and a hydroxyl group, such as one or more alcohols selected from ethanol, n-propanol, and n-butanol.

[0052] The C2+ alcohol to be dehydrated may be a single C2+ alcohol species, or may be a mixture of two or more C2+ alcohol species.In some or all embodiments of the invention, the C2+ alcohol to be dehydrated is a single C2+ alcohol species.

[0053] In the present invention, the dehydration process is carried out in the presence of at least one aluminosilicate zeolite catalyst, which is a medium-porous zeolite having a 3-dimensional framework structure.

[0054] Aluminosilicate zeolites are crystalline microporous materials having a framework structure consisting of tetrahedrons of SiO4 and AlO4 that share vertices. Such tetrahedral species are generally referred to as TO4 species, in which the T atoms are silicon or aluminum. The aluminum 'T' atoms may be partially or completely replaced by one or more gallium, boron or iron atoms. For the purposes of the present invention, such gallium, boron or iron modified zeolites are considered to fall within the definition of the term 'aluminosilicate zeolites'.

[0055] Silicoaluminophosphate structures containing PO4 tetrahedra are not considered to be aluminosilicate materials, and therefore such silicoaluminophosphates (eg, SAPO-type materials) are not within the scope of the present invention.

[0056] The zeolite framework topology contains a regular array of pores, channels and / or holes of varying sizes, shapes and dimensions. These framework topologies or structure types of zeolites are assigned three-letter structure codes by the Structure Commission of the International Zeolite Association under the authority of IUPAC.

[0057] A description of zeolites, their framework codes, structures, dimensions, properties and synthesis methods can be found in the web-based version (http: / / www.iza-structure.org / databases / ). Atlas of Zeolite Framework Types (C. Baerlocher, WM Meier, DH Olson, 5th edition, Elsevier, Amsterdam, 2001).

[0058] Zeolite crystals contain a system of molecular-sized pores or channels with fixed geometry and size, and can be classified according to the number of channels extending in different directions within the zeolite framework structure. Zeolites are described as 1-, 2-, or 3-dimensional if they have one, two, or three channels in different directions, respectively.

[0059] Zeolites can also be classified according to the size of their pores. Zeolite channels with pore openings defined by 8 T atoms in tetrahedral coordination are defined as having 8-membered rings, zeolite channels with pore openings defined by 10 T atoms in tetrahedral coordination are defined as having 10-membered rings, and zeolite channels with pore openings defined by 8 T atoms in tetrahedral coordination are defined as having 12-membered rings. Zeolites can also be conveniently classified based on the channels containing the largest pore openings, and zeolites with the largest pore openings defined by 8 T atoms in tetrahedral coordination (8-membered rings) can be defined as "small pore zeolites" (8-membered rings); zeolites with the largest pore openings defined by 10 T atoms in tetrahedral coordination (10-membered rings) can be defined as "medium pore zeolites"; and zeolites with the largest pore openings defined by 12 T atoms in tetrahedral coordination (12-membered rings) can be defined as "large pore zeolites".

[0060] Non-limiting examples of small pore zeolites are those of framework types CHA, RHO and KFI.

[0061] Non-limiting examples of medium pore zeolites are those of framework types TON, MTT, FER, MWW, MFI, EUO, MEL, MFS and TER.

[0062] Non-limiting examples of large pore zeolites are those of framework types MOR, BEA, FAU, EON, IWV, SEW and USI.

[0063] The degree to which the dehydration reaction is promoted may vary depending on factors such as the structure of the zeolite and the nature of the promoter used in the reaction.Ideally, to promote increased productivity, the zeolite channels must be sized to enable the promoter to diffuse into the zeolite channels.

[0064] In some or all embodiments of the present invention, the catalyst comprises at least one aluminosilicate zeolite catalyst, which is a mesoporous zeolite with a 3-dimensional framework structure. In some or all embodiments of the present invention, the catalyst is at least one aluminosilicate zeolite catalyst, which is a mesoporous zeolite with a 3-dimensional framework structure.

[0065] In some or all embodiments of the invention, the catalyst is an aluminosilicate zeolite selected from the framework types MFI and MEL. Examples of aluminosilicate zeolites of the framework type MFI include ZSM-5. Examples of aluminosilicate zeolites of the framework type MEL include ZSM-11.

[0066] Typically, zeolite is synthesized from a synthetic mixture comprising a silicon dioxide source, an aluminum oxide source, an alkali metal hydroxide and water in a desired ratio. With or without stirring, the synthetic mixture is maintained under temperature, pressure and time conditions sufficient to form a crystalline aluminosilicate zeolite. The resulting zeolite contains an alkali metal as a cation. Such a cation can be replaced with known ion exchange techniques. For example, zeolite can be contacted with an aqueous solution of an ammonium salt to replace the alkali metal cation with an ammonium ion. Zeolite in the form of ammonium is also commercially available.

[0067] Although the ammonium form of the zeolite may be catalytically active, for use in the present invention, it is preferred to use the zeolite in the hydrogen form (H form). H form zeolite is commercially available. Alternatively, the ammonium form of the zeolite may be converted to the H form by known techniques, such as by calcining the ammonium form of the zeolite in air or an inert gas at high temperature (e.g., at 500° C. or higher).

[0068] In some or all embodiments of the invention, the aluminosilicate zeolite catalyst is a zeolite that is a zeolite in the hydrogen form (H form).

[0069] For use in the present invention, the aluminosilicate zeolite may be composited with at least one binder material. The binder material may be a refractory inorganic oxide such as silica, alumina, alumina-silicate, magnesium silicate, magnesium aluminum silicate, titania and zirconia.

[0070] For use in the present invention, the relative proportions of the aluminosilicate zeolite and binder material in the composite material may vary widely.Suitably, the binder material may be present in an amount of from 10% to 90% by weight of the composite material.

[0071] For use in the present invention the silica to alumina molar ratio of the zeolite may vary widely but is suitably in the range 10-300, such as in the range 20-280, for example in the range 20-100.

[0072] The co-catalyst compound used for the present invention is an organic carbonyl compound or a derivative thereof. In the present invention, the co-catalyst compound can be used alone, or a mixture of any two or more co-catalyst compounds can also be used for the present invention. In some or all embodiments of the present invention, only a single species of co-catalyst compound is used.

[0073] In some or all embodiments of the present invention, the co-catalyst compound used in the present invention is selected from one or more compounds selected from the following:

[0074] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0075] (ii) acetal derivatives of aldehydes of formula I;

[0076] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0077] (iv) ketal derivatives of ketones of formula II;

[0078] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0079] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group.

[0080] The co-catalysts of compounds (i) to (vi) may be used alone, or mixtures of any two or more co-catalyst compounds may also be used in the present invention. In some or all embodiments of the present invention, only a single species of co-catalyst compound is used.

[0081] The co-catalyst compound used in the present invention can be selected from (i) Formula I (R A1 CHO) aldehyde (where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11alkyl, or an optionally substituted aromatic group) or (ii) an acetal derivative of an aldehyde of formula I.

[0082] Mixtures of aldehydes of formula I and their acetal derivatives may also be used in the present invention.

[0083] In some or all embodiments of the invention, R A1 is hydrogen, a C1-C7 alkyl group, a C3-C7 alkyl group in which 3 or more carbon atoms are combined to form a ring, or an optionally substituted aromatic group.

[0084] In some or all embodiments of the invention, R A1 C3-C 11 Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0085] In the present invention, R A1 Can be a straight chain C1-C 11 Alkyl or branched C3-C 11 alkyl.

[0086] In some or all embodiments of the invention, R A1 is a straight chain alkyl group, and the aldehyde of formula I is selected from n-butyraldehyde, n-hexanal and n-octanal.

[0087] Advantageously, the applicant has found that, with the use of the corresponding C3-C 11 Compared with straight chain aldehydes, the use of R A1 C3-C 11 Aldehydes of formula I which are branched alkyl or optionally substituted aromatic groups may lead to improved stability of the catalyst.

[0088] In some or all embodiments of the invention, R A1 is a branched C3-C7 alkyl group, and suitably, the aldehyde of formula I is selected from isobutyraldehyde and 2-ethylhexanal.

[0089] In some or all embodiments of the invention, in the aldehyde of formula I, R A1 For wherein 3 or more carbon atoms combine to form a C3-C7 alkyl ring. Suitably, 4-7 carbon atoms (e.g. 4-6 carbon atoms) can combine to form a ring. The limiting examples of such aldehyde compounds are cyclopentanecarboxaldehyde, cyclohexanecarboxaldehyde and cycloheptanecarboxaldehyde.

[0090] In some or all embodiments, R A1is an optionally substituted aromatic group, wherein the optional substituents are independently selected from halogen, substituted or unsubstituted hydrocarbon substituents or compounds of the formula -CHO, -CO2R, -COR or -OR, wherein R is hydrogen or a substituted or unsubstituted hydrocarbon substituent. A1 In the embodiment where R is a substituted aromatic group, the aromatic ring may contain one or more substituents at any meta, ortho or para position of the aromatic ring; preferably, when R A1 When it is a substituted aromatic group, the aromatic ring is a para-substituted aromatic ring.

[0091] In which R A1 In some or all embodiments that are substituted aromatic groups, the substituents are substituted or unsubstituted hydrocarbyl substituents containing 1-11 carbon atoms, preferably 1-9 carbon atoms, more preferably 1-7 carbon atoms, such as 1-6 carbon atoms.

[0092] The term unsubstituted hydrocarbyl as used herein refers to a hydrocarbyl component containing 1 to 11 carbon atoms, preferably 1 to 9 carbon atoms, more preferably 1 to 7 carbon atoms, for example 1 to 6 carbon atoms. The hydrocarbyl substituent is preferably C1-C 11 Alkyl or a C3-C4-C6-alkyl group in which 3 or more carbon atoms are combined to form a ring 11 In some or all embodiments, the hydrocarbyl substituent is a C1-C7 alkyl or a C3-C7 alkyl in which 3 or more carbon atoms are combined to form a ring. In some or all embodiments, the hydrocarbyl substituent is a C3-C7 alkyl. 11 Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0093] The term substituted hydrocarbyl as used herein refers to a hydrocarbyl component as described above which contains one or more heteroatoms. The one or more heteroatoms may conveniently be independently selected from nitrogen, oxygen or halogen.

[0094] The acetal derivatives of the aldehyde of formula I also act as a co-catalyst in the present invention. In the present invention, the term 'acetal derivatives' also includes hemiacetal derivatives of the aldehyde of formula I. As those skilled in the art will readily appreciate, acetals are functional groups derived from aldehydes by substituting the carbonyl groups of the aldehyde with two alkoxy groups. Hemiacetals are aldehydes derived from aldehydes by substituting the carbonyl groups of the aldehyde with alkoxy groups and hydroxy groups. Therefore, the acetal derivatives of the aldehyde of formula I can be represented by the following general structural formula:

[0095] (Formula IA)

[0096] Where R A1 has the meanings in the above formula I, and each R A2 and R A3 is alkyl or hydrogen, provided that RA2 and R A3 Not hydrogen at the same time.

[0097] Suitably, each R A2 and R A3 is an alkyl group, wherein the alkyl group is a C1-C6 straight chain or branched chain alkyl group. A2 and R A3 Can be the same or different.

[0098] In some or all embodiments of the invention, R A2 and R A3 Each is selected from C1 or C2 alkyl. In these embodiments, R A2 and R A3 Can be the same or different.

[0099] In some or all embodiments of the invention, R A2 and R A3 are the same and are each a C1 alkyl group. In this case, the acetal derivative of Formula IA is a dimethoxyacetal. Specific non-limiting examples of dimethoxyacetals are dimethoxymethane, 1,1-dimethoxyethane and 1,1-dimethoxyheptane.

[0100] In some or all embodiments of the invention, the acetal derivative of the aldehyde of formula I is a hemiacetal. Suitably, in these embodiments, R A2 and R A3 One of them is hydrogen, and R A2 and R A3 One of the hemiacetals is C1-C6 alkyl, for example C1-C3 alkyl. Suitably, the hemiacetal is methoxy hemiacetal.

[0101] In some or all embodiments of the invention, the aldehyde of formula I is a cyclic aldehyde having 4 to 8 carbon atoms, such as 4 to 6 carbon atoms. Suitably, in these embodiments, each R A2 and R A3 are C1-C2 alkyl groups and may be the same or different. Suitably, in these embodiments, R A2 and R A3 are the same and may be a C1 alkyl group.

[0102] Aldehydes of formula I and their acetal derivatives are commercially available.

[0103] In the present invention, the co-catalyst of compound (i) or (ii) can be added as a component of the feed to the dehydration process. Alternatively and / or in addition, the co-catalyst of compound (i) or (ii) can be generated in situ by adding to the process any compound (precursor compound) from which the aldehyde or acetal derivative of formula I is generated in situ.

[0104] Suitable precursor compounds for the aldehyde compounds of formula I include acetal derivatives thereof.

[0105] The aldehyde compound of formula I can also be generated in situ by a retro-aldol condensation reaction of a β-hydroxyaldehyde compound or a compound generated by its dehydration. For example, when it is desired to generate the co-catalyst compound acetaldehyde in situ in a dehydration process, a suitable precursor compound that can be added to the process can be crotonaldehyde or β-hydroxyaldehyde, 3-hydroxybutyraldehyde.

[0106] In some or all embodiments of the present invention, the precursor of the co-catalyst compound (i) is a β-hydroxyaldehyde compound or a compound resulting from the dehydration thereof.

[0107] The co-catalyst compound used in the present invention can also be selected from (iii) formula II (R K1 COR K2 ) of ketone (where R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bound they can form cyclic ketones) and (iv) ketal derivatives of ketones of formula II.

[0108] Mixtures of ketones of formula II and their ketal derivatives may also be used in the present invention.

[0109] In the present invention, the ketone of formula II may be a straight-chain alkyl ketone, a branched-chain alkyl ketone, an aromatic ketone or a cyclic ketone.

[0110] Advantageously, the applicant has found that the use of a ketone wherein R K1 and R K2 The ketone of formula II in which at least one of the groups is a branched alkyl group, or an optionally substituted aromatic group may result in an improved stability of the catalyst.

[0111] In some or all embodiments of the invention, each R K1 and R K2The group may independently be a C1-C7 alkyl group, a C3-C7 alkyl group in which 3 or more carbon atoms are bonded to form a ring, or an optionally substituted aromatic group.

[0112] In some or all embodiments of the invention, each R K1 and R K2 Can be independently C3-C 11 Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0113] In the present invention, each R K1 and R K2 Can be independently a straight chain C1-C 11 Alkyl or branched C3-C 11 alkyl.

[0114] In some or all embodiments of the invention, in the ketone of formula II, each R K1 and R K2 It may be independently a C3-C7 alkyl group in which 3 or more carbon atoms are combined to form a ring. Suitably, 4 to 7 carbon atoms (e.g., 4 to 6 carbon atoms) may be combined to form a ring.

[0115] In some or all embodiments, each R K1 and R K2 may be independently an optionally substituted aromatic group, wherein the optional substituents may be independently selected from halogen, substituted or unsubstituted hydrocarbon substituents or compounds of the formula -CHO, -CO2R, -COR or -OR, wherein R is hydrogen or a substituted or unsubstituted hydrocarbon substituent. K1 and R K2 In the embodiment where one or both of are substituted aromatic groups, the aromatic ring may contain one or more substituents at any meta, ortho or para position of the aromatic ring; preferably, when R K1 and R K2 When one or both of them are substituted aromatic groups, the aromatic ring is a para-substituted aromatic ring.

[0116] In which R K1 and R K2 In some or all embodiments where one or both of are substituted aromatic groups, the substituents are substituted or unsubstituted hydrocarbyl substituents containing 1-11 carbon atoms, preferably 1-9 carbon atoms, more preferably 1-7 carbon atoms, such as 1-6 carbon atoms.

[0117] The term unsubstituted hydrocarbyl as used herein refers to a hydrocarbyl component comprising 1 to 11 carbon atoms, preferably 1 to 9 carbon atoms, more preferably 1 to 7 carbon atoms, for example 1 to 6 carbon atoms. The hydrocarbyl substituent is preferably C1-C11 Alkyl or a C3-C4-C6-alkyl group in which 3 or more carbon atoms are combined to form a ring 11 In some or all embodiments, the hydrocarbyl substituent is a C1-C7 alkyl or a C3-C7 alkyl in which 3 or more carbon atoms are combined to form a ring. In some or all embodiments, the hydrocarbyl substituent is a C3-C7 alkyl. 11 Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0118] The term substituted hydrocarbyl as used herein refers to a hydrocarbyl component as described above, which contains one or more heteroatoms. The one or more heteroatoms may conveniently be independently selected from nitrogen, oxygen or halogen.

[0119] In some or all embodiments of the invention, R K1 and R K2 The same or different and each is a branched C3-C 11 Alkyl group, preferably a branched C3-C7 alkyl group.

[0120] In some or all embodiments of the invention, R K1 and R K2 The same or different and each is a C1-C3 alkyl group.

[0121] In some or all embodiments of the invention, R K1 and R K2 One or both of are C3 alkyl, and the C3 alkyl is a linear or branched C3 alkyl. Suitably, in these embodiments, R K1 and R K2 Each is a C3 branched alkyl group, and the ketone of Formula II is 2,4-dimethyl-3-pentanone.

[0122] In some or all embodiments of the invention, R K1 and R K2 are the same and are each C3-C 11 Alkyl, preferably C3-C7 alkyl, such as n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl or heptyl.

[0123] Specific non-limiting examples of ketones suitable for use in the present invention are acetone, 3-pentanone, 4-heptanone and 5-nonanone, wherein R K1 and R K2 are the same.

[0124] In some or all embodiments of the invention, R K1 and R K2 are different, where R K1 is a C1-C3 alkyl group, and RK2 is a C1-C7 alkyl group, or an optionally substituted aromatic group. Suitably, in these embodiments, R K1 is a C1 alkyl group, and R K2 is a C1-C3 alkyl group, or an optionally substituted aromatic group.

[0125] Ketones suitable for use in the present invention (wherein R K1 and R K2 Specific non-limiting examples of (are different) are 2-butanone, 2-heptanone, 2-nonanone and acetophenone.

[0126] In some or all embodiments of the present invention, the ketone of formula II is a cyclic ketone, and is suitably selected from cyclic ketones comprising 4 to 12 carbon atoms (e.g., 4 to 6 carbon atoms). Specific non-limiting examples of the cyclic ketones of formula II are cyclobutanone, cyclopentanone, and cyclohexanone.

[0127] The ketal derivatives of ketones of formula II also act as co-catalysts in the present invention. In the present invention, the term 'ketal derivatives' also includes hemiketal derivatives of ketones of formula II. As readily understood by those skilled in the art, ketals are functional groups derived from ketones by substituting the carbonyl groups of the ketone with two alkoxy groups. Hemiketals are derived from ketones by substituting the carbonyl groups of the ketone with alkoxy groups and hydroxy groups. Therefore, the ketal derivatives of ketones of formula II can be represented by the following general structural formula:

[0128] (Formula IIIK)

[0129] Where R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form a cyclic ketone, and each R K3 and R K4 is alkyl or hydrogen, provided that R K3 and R K4 Not hydrogen at the same time.

[0130] Suitably, each R K3 and R K4 is an alkyl group, wherein the alkyl group is a C1-C6 straight chain or branched chain alkyl group. K3 and R K4 Can be the same or different.

[0131] In some or all embodiments of the invention, R K3 and R K4Each is selected from C1 or C2 alkyl. In these embodiments, R K3 and R K4 Can be the same or different.

[0132] In some or all embodiments of the invention, R K3 and R K4 are the same and are each a C1 alkyl group. In this case, the ketal of formula IIIK is a dimethoxyketal. Specific non-limiting examples of dimethoxyketals are 2,2-dimethoxypropane and 2,2-dimethoxybutane.

[0133] In some or all embodiments of the invention, the ketal derivative of the ketone of formula II is a hemiketal. Suitably, in these embodiments, R K3 and R K4 One of them is hydrogen, and R K3 and R K4 One of the alkyl groups is C1-C6 alkyl, for example C1-C3 alkyl.

[0134] In some or all embodiments of the invention, the ketone of formula II is a cyclic ketone having 4 to 12 carbon atoms, such as 4 to 6 carbon atoms, and each R K3 and R K4 are C1-C2 alkyl groups and may be the same or different. Suitably, in these embodiments, R K3 and R K4 are the same and may be a C1 alkyl group.

[0135] Specific examples of ketal derivatives of the cyclic ketone of formula II include cyclohexanone dimethyl ketal.

[0136] Examples of suitable ketones of formula II from which the ketal derivatives of formula IIIK are derived include the following compounds: methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, 2,4-dimethyl-3-pentanone, 2-heptanone, 4-heptanone and 5-nonanone.

[0137] Mixtures of ketone derivatives of the formula II and ketal derivatives of the formula IIIK can also be used in the present invention.

[0138] Ketones of formula II and their ketal derivatives are commercially available.

[0139] In the present invention, the cocatalyst of compound (iii) or (iv) can be added as a component of the feed to the dehydration process. Alternatively and / or in addition, the cocatalyst of compound (iii) or (iv) can be generated in situ by adding to the process any compound (precursor compound) from which the ketone or ketal derivative of formula II is generated in situ.

[0140] Suitable precursor compounds for producing the keto compounds of formula II include ketal derivatives thereof.

[0141] The ketone compound of formula II can also be generated in situ by a retro-aldol condensation reaction of a β-hydroxyketone compound. For example, when it is desired to generate acetone in situ in the dehydration process, the precursor compound can be the β-hydroxyketone, 4-hydroxy-4-methyl-3-pentan-2-one.

[0142] In some or all embodiments of the present invention, the precursor of the co-catalyst compound (iii) is a β-hydroxyketone compound or a compound resulting from the dehydration thereof.

[0143] The co-catalyst compound used in the present invention may be further selected from (v) E1 CO2R E2 Esters of formula III (wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group) and (vi) formula R E1 (CO2R E2 )2(Formula IV) of the diester (wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group).

[0144] Mixtures of esters of formula III and diesters of formula IV may also be used in the present invention.

[0145] Advantageously, the applicant has found that the use of a ketone wherein R E1 and R E2 The ketone of formula II in which at least one of the groups is a branched alkyl group, or an optionally substituted aromatic group may result in an improved stability of the catalyst.

[0146] In some or all embodiments of the invention, each R E1 and R E2 The group may independently be a C1-C7 alkyl group, a C3-C7 alkyl group in which 3 or more carbon atoms are bonded to form a ring, or an optionally substituted aromatic group.

[0147] In some or all embodiments of the invention, each R E1 and R E2 Can be independently C3-C 11Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0148] In the present invention, each R E1 and R E2 Can be independently a straight chain C1-C 11 Alkyl or branched C3-C 11 alkyl.

[0149] In some or all embodiments of the invention, in the ester of formula III or the diester of formula IV, each R E1 and R E2 It may be independently a C3-C7 alkyl group in which 3 or more carbon atoms are combined to form a ring. Suitably, 4 to 7 carbon atoms (e.g., 4 to 6 carbon atoms) may be combined to form a ring.

[0150] In some or all embodiments, each R E1 and R E2 may be independently an optionally substituted aromatic group, wherein the optional substituents may be independently selected from halogen, substituted or unsubstituted hydrocarbon substituents or compounds of the formula -CHO, -CO2R, -COR or -OR, wherein R is hydrogen or a substituted or unsubstituted hydrocarbon substituent. E1 and R E2 In the embodiment where one or both of are substituted aromatic groups, the aromatic ring may contain one or more substituents at any meta, ortho or para position of the aromatic ring; preferably, when R E1 and R E2 When one or both of are substituted aromatic groups, the aromatic ring is a para-substituted aromatic ring.

[0151] In which R E1 and R E2 In some or all embodiments where one or both of are substituted aromatic groups, the substituents are substituted or unsubstituted hydrocarbyl substituents containing 1-11 carbon atoms, preferably 1-9 carbon atoms, more preferably 1-7 carbon atoms, such as 1-6 carbon atoms.

[0152] The term unsubstituted hydrocarbyl as used herein refers to a hydrocarbyl component comprising 1 to 11 carbon atoms, preferably 1 to 9 carbon atoms, more preferably 1 to 7 carbon atoms, for example 1 to 6 carbon atoms. The hydrocarbyl substituent is preferably C1-C 11 Alkyl or a C3-C4-C6-alkyl group in which 3 or more carbon atoms are combined to form a ring 11 In some or all embodiments, the hydrocarbyl substituent is a C1-C7 alkyl or a C3-C7 alkyl in which 3 or more carbon atoms are combined to form a ring. In some or all embodiments, the hydrocarbyl substituent is a C3-C7 alkyl. 11Alkyl, for example C3-C7 alkyl, for example n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl or n-octyl alkyl.

[0153] The term substituted hydrocarbyl as used herein refers to a hydrocarbyl component as described above, which contains one or more heteroatoms. The one or more heteroatoms may conveniently be independently selected from nitrogen, oxygen or halogen.

[0154] In some or all embodiments of the present invention, the ester of formula III is an alkyl carboxylate wherein R E1 is an alkyl group having 1 to 9 carbon atoms, such as 2 to 7 carbon atoms, such as 3 to 7 carbon atoms, and R E2 is an alkyl group having 1 to 3 carbon atoms, such as methyl or ethyl.

[0155] In some or all embodiments of the present invention, the ester of formula III is an alkyl carboxylate wherein R E2 is an alkyl group having 1 to 9 carbon atoms, such as 2 to 7 carbon atoms, such as 3 to 7 carbon atoms, and R E1 is an optionally substituted aromatic group.

[0156] In some or all embodiments of the invention, the ester of formula III can be a linear alkyl carboxylate or a branched alkyl carboxylate.

[0157] In some or all embodiments of the present invention, the ester of formula III is a linear alkyl carboxylate, wherein R E1 is an alkyl group having 1 to 9 carbon atoms, and R E2 It is methyl or ethyl.

[0158] In some or all embodiments of the present invention, the ester of formula III is a linear alkyl carboxylate, wherein R E1 is an alkyl group having 2 to 7 carbon atoms, and R E2 It is methyl or ethyl.

[0159] In some or all embodiments of the present invention, the ester of formula III is a linear alkyl carboxylate, wherein R E1 is an alkyl group having 1 to 9 carbon atoms, and R E2 It is methyl or ethyl.

[0160] Specific non-limiting examples of linear alkyl carboxylates of formula III suitable for use in the present invention are methyl acetate, methyl propionate, methyl n-butyrate, methyl n-valerate, methyl n-hexanoate, methyl n-heptanoate, methyl n-octanoate, ethyl acetate, ethyl propionate, ethyl n-butyrate, ethyl n-valerate, ethyl n-hexanoate, ethyl n-heptanoate and ethyl n-octanoate.

[0161] In some or all embodiments of the present invention, the diester compound of formula IV is a diester wherein RE1 is an alkyl group having 1 to 9 carbon atoms, such as 2 to 7 carbon atoms, such as 2 to 4 carbon atoms or 3 to 7 carbon atoms, and R E2 is an alkyl group having 1 to 3 carbon atoms, such as methyl or ethyl.

[0162] In some or all embodiments of the present invention, the diester compound of formula IV is selected from at least one of dimethyl succinate, dimethyl glutarate, and dimethyl adipate.

[0163] In the present invention, the cocatalyst of compound (v) or (vi) can be added as a component of the feed to the dehydration process. Alternatively and / or in addition, the cocatalyst of compound (v) or (vi) can be generated in situ by adding to the process any compound (precursor compound) from which an ester of formula III or a diester compound of formula IV can be generated in situ.

[0164] Precursor compounds useful for in situ generation of the ester promoter compound of formula III include compounds of formula R E1 CO2X compounds, wherein X is selected from hydrogen, halogen (such as chlorine) and -C(=O)-R 1 Group (where R 1 is hydrogen or alkyl).

[0165] Can be used to generate in situ formula II (R E1 (CO2R E2 )2) The precursor compound of the diester promoter compound includes a compound of formula R E1 (CO2X)2 compounds, wherein each X can be the same or different and is selected from hydrogen, halogen (such as chlorine) and -C(=O)-R 1 Group (where R 1 is hydrogen or alkyl).

[0166] In the present invention, throughout the dehydration reaction, the molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1. The term 'molar ratio of the co-catalyst to the C2+ alcohol' and the like refers to the molar ratio of the total amount of the C2+ alcohol present in the dehydration reaction to the total amount of the co-catalyst compound in the dehydration reaction, i.e. (total amount of the C2+ alcohol):(total amount of the co-catalyst compound).

[0167] In some or all embodiments of the invention, the molar ratio of the co-catalyst to the C2+ alcohol is maintained in the range of 0.000001:1 to less than 0.5:1, preferably in the range of 0.00005:1 to less than 0.5:1. In some or all embodiments of the invention, the molar ratio of the co-catalyst to the C2+ alcohol is maintained in the range of 0.00001:1 to less than 0.5:1, such as 0.00005:1 to 0.2:1, such as 0.0001:1 to 0.2:1. In some or all embodiments of the invention, the molar ratio of the co-catalyst to the C2+ alcohol is maintained in the range of 0.01:1 to less than 0.5:1, such as 0.01:1 to 0.2:1, such as 0.02:1 to 0.2:1.

[0168] Suitably, in the present invention, in the whole dehydration reaction, relative to the total amount of C2+ alcohol, the total amount of cocatalyst is maintained at an amount of at least 1 ppm. In some or all embodiments of the present invention, in the whole dehydration reaction, relative to the total amount of C2+ alcohol, the total amount of cocatalyst is maintained at an amount of at least 0.001 mol %, such as 0.001 mol % to an amount less than 50 mol %, such as 0.001 mol % to 20 mol %, such as 0.005 mol % to 20 mol %. In some or all embodiments of the present invention, in the whole dehydration reaction, relative to the total amount of C2+ alcohol, the total amount of cocatalyst is maintained at an amount of at least 0.01 mol %, such as 0.01 mol % to an amount less than 50 mol %, such as 0.01 mol % to 20 mol %, such as 0.05-20 mol %. In some or all embodiments of the invention, the total amount of the promoter is maintained at an amount of at least 1 mol %, such as 1 mol % to less than 50 mol %, such as 1 mol % to 20 mol %, such as 2-20 mol %, relative to the total amount of C2+ alcohol throughout the dehydration reaction.

[0169] Suitably, in the present invention, the dehydration process can be carried out as a stand-alone process. In such a case, the dehydration reaction is not carried out, for example, as part of a co-production process. Therefore, suitably, in the present invention, the feed components of the process are one or more C2+ alcohols and at least one co-catalyst compound, the co-catalyst compound being a carbonyl compound or a derivative thereof, for example at least one co-catalyst compound selected from the co-catalyst compounds of (i) to (vi) above.

[0170] However, typically the product stream of the C2+ alcohol dehydration reaction will contain one or more ether products, water, unconverted C2+ alcohol and one or more promoter compounds and / or promoter compound precursors. Therefore, in some or all embodiments of the present invention, one or more components of the product stream of the dehydration process are recycled as feed to the process. In such cases, one or both of the ether product and water are additional feed components of the dehydration process.

[0171] Therefore, in some or all embodiments of the present invention, the feed components of the dehydration process are C2+ alcohols, at least one promoter compound (the promoter compound is a carbonyl compound or a derivative thereof, such as at least one promoter compound selected from the promoter compounds of (i) to (vi) above) and one or both of the ether product and water.

[0172] In cases when it is desired to generate the promoter in situ in the dehydration process, the feed components to the process may be a compound of at least one C2+ alcohol and at least one precursor of one or more promoters.

[0173] Thus, in some or all embodiments of the present invention, the feed components of the dehydration process are C2+ alcohols; (i) one or both of the co-catalyst compounds described herein and (ii) at least one precursor compound of the co-catalyst compounds described herein; and one or both of the ether product and water.

[0174] The feed components to the process may be supplied to the process in one or more feed streams.

[0175] The dehydration process is carried out as a heterogeneous process, either as a gas phase heterogeneous process or as a liquid phase heterogeneous process.

[0176] The type of reactor used for the dehydration process is not limited, and it can be suitably carried out in any type of reactor in which a gas phase heterogeneous process or a liquid phase heterogeneous process can be carried out. Non-limiting types of reactors in which the dehydration reaction can be carried out include tank reactors, multi-tubular reactors, plug flow reactors, loop reactors, fluidized bed reactors, and reactive distillation columns.

[0177] The dehydration process may be carried out at a temperature of 100° C. to 300° C. In some or all embodiments of the invention, the dehydration process is carried out at a temperature of 140° C. to 250° C., such as 150° C. to 250° C.

[0178] Suitably, the dehydration process may be carried out at atmospheric pressure or at elevated pressure.

[0179] In some or all embodiments of the invention, the dehydration process is carried out at a total pressure of from atmospheric pressure to 3000 kPa. When the process is carried out in the liquid phase, higher total pressures, such as from 4000 kPa to 10,000 kPa, may be required to keep the ether product in solution.

[0180] In some or all embodiments of the invention, the dehydration process is carried out as a heterogeneous gas phase process at a total pressure of atmospheric pressure to 3000 kPa. In these embodiments, the temperature can be 100°C to 300°C, such as 140°C to 250°C, such as 150°C to 250°C.

[0181] For the gas phase process, the method can be carried out at a total gas hourly space velocity (GHSV) of 500-40,000 h -1 within the scope.

[0182] For the liquid phase method, the method can be carried out at a total liquid hourly space velocity (LHSV) of 0.2-20 h -1 within the scope.

[0183] The dehydration process may be carried out using one or more zeolite catalyst beds suitably selected from fixed bed, fluidised bed and moving bed catalysts.

[0184] The dehydration process can be operated as a continuous or batch process, preferably as a continuous process.

[0185] The dehydration process produces a crude reaction product comprising one or more ethers and water as reaction products, unreacted C2+ alcohols and one or more compounds selected from the group consisting of co-catalyst compounds and co-catalyst precursor compounds. One or more components of the crude reaction product can be recycled to the process as feed.

[0186] One or more ether products may be recovered from the crude reaction product by any suitable method, such as by distillation.

[0187] Without being bound by theory, the productivity of a catalyst will generally decrease over time during production; in an industrially applied catalytic process, one of the ways by which the decrease in productivity can be compensated is by increasing the reaction temperature to maintain a constant productivity. A disadvantage of increasing the reaction temperature is that this may result in an increase in unwanted by-products or may result in a decrease in selectivity; another disadvantage of increasing the reaction temperature is that such an increase in temperature may accelerate the rate of catalyst deactivation. However, without wishing to be bound by theory, it is believed that in the present invention, a decrease in catalyst productivity can be at least partially compensated by increasing the relative concentration of the promoter in the C2+ alcohol feed, and thus the need to increase the temperature to compensate for any decrease in productivity that may occur over time during production can be reduced or eliminated; similarly, a decrease in catalyst productivity can be at least partially compensated by changing the promoter used or by adding a second or further additional promoter compound to one or more C2+ alcohol feeds as production increases over time.

[0188] In addition to the beneficial effect on the dehydration rate of the C2+ alcohol reaction carried out in the presence of at least one aluminosilicate zeolite catalyst (the aluminosilicate zeolite catalyst is a medium-porous zeolite having a 3-dimensional framework structure), it is believed that the use of the co-catalyst described herein can lead to an increase in catalyst stability and make the catalyst more resistant to deactivation caused by impurities present in the C2+ alcohol feed.

[0189] In a further aspect of the present invention, a method for dehydrating C2+ alcohols to ether products in the presence of a catalyst is provided, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst is a medium-pore zeolite having a 3-dimensional framework structure, and wherein before using the catalyst in the dehydration method, the catalyst has been impregnated with a co-catalyst, the co-catalyst being an organic carbonyl compound or a derivative thereof.

[0190] In a particular embodiment of this further aspect of the invention, there is provided a process for dehydrating a C2+ alcohol to an ether product in the presence of a catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst being a mesoporous zeolite having a 3-dimensional framework structure, and wherein prior to using the catalyst in the dehydration process, the catalyst has been impregnated with a promoter selected from:

[0191] (i) Formula R A1 CHO (formula I) aldehyde, R A1 CHO, where R A1 is hydrogen, C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group;

[0192] (ii) acetal derivatives of aldehydes of formula I;

[0193] (iii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is C1-C 11 Alkyl, C3-C 11 alkyl, or an optionally substituted aromatic group, and in addition R K1 and R K2 Together with the carbonyl carbon atom to which they are bonded, they can form cyclic ketones;

[0194] (iv) ketal derivatives of ketones of formula II;

[0195] (v) Formula R E1 CO2R E2 (Formula III) wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group; and

[0196] (vi) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is C1-C 11 Alkyl, C3-C 11 an alkyl group, or an optionally substituted aromatic group.

[0197] In this further aspect of the invention, the feed to the dehydration process comprises C2+ alcohols and may optionally comprise other components such as ethers, water or at least one co-catalyst, which is an organic carbonyl compound or a derivative thereof, such as at least one co-catalyst compound selected from the co-catalyst compounds of (i) to (vi) above, or a precursor compound thereof.

[0198] The invention will now be illustrated with reference to the following non-limiting examples. Example

[0199] The ZSM-5 catalyst used in Examples 1-11 was obtained from Zeolyst International in ammonium form. The ZSM-11 catalyst used in Example 12 was obtained from ACS Material in ammonium form. The ZSM-5 and ZSM-11 catalysts were used in their H form after conversion by calcination at 500°C in air.

[0200] General reaction method and equipment I

[0201] The ethanol dehydration reaction was carried out using a 16-channel parallel fixed bed stainless steel reactor system. Each reactor (2 mm inner diameter) was heated to maintain a temperature of 150 ° C or 200 ° C. Each reactor encapsulated a 25 mg catalyst bed (particle size fraction of 100-200 micron diameter), which was loaded on top of a 6 cm deep inert material (corundum) bed. The reactor volume above the catalyst was also filled with corundum. The reactor was installed in a downflow configuration.

[0202] During the entire reaction, each reactor was maintained at a temperature of 150°C and a total pressure of 1100 kPa. A gaseous feed comprising 10 mol % ethanol and an inert gas was added at a rate of 13 mmol h -1 A constant flow rate of ethanol of 100 mmol / l was introduced into the reactor and allowed to flow through the catalyst bed for a period of at least 24 hours. Different concentrations of promoter were added to the feed to determine the effect on ether yield. When the promoter was added, the flow rate of the inert gas was reduced to maintain a constant gas hourly space velocity, and the ethanol flow rate was maintained at 13 mmol / l. -1 .

[0203] The effluent stream from each reactor was diluted with an inert gas (nitrogen) and periodically analyzed by on-line gas chromatography to determine the yield of the ether product.

[0204] General Reaction Methods and Equipment II

[0205] The n-hexanol dehydration reaction was carried out using a single-channel fixed-bed stainless steel reactor system. The reactor encapsulated a 350 mg ZSM-5 catalyst bed with a silica to alumina ratio (SAR) of 80. The particle size fraction of the catalyst was 250-500 micron diameter. The catalyst was loaded in a front bed of less than 170 mg inert material (silicon carbide) and a rear bed of more than 600 mg inert material (silicon carbide).

[0206] The reactor was maintained at a temperature of 160°C and a pressure of 20 barg throughout the reaction.

[0207] Example 1

[0208] This example demonstrates the effect of ethyl formate on the dehydration reaction of ethanol over different ZSM-5 catalysts at a reaction temperature of 150°C.

[0209] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 1.

[0210] Table 1

[0211]

[0212] SAR indicates the silica:alumina molar ratio of the zeolite

[0213] The results in Table 1 show that the use of ethyl formate enhances the space-time yield of diethyl ether.

[0214] Example 2

[0215] This example demonstrates the effect of ethyl formate on the dehydration reaction of ethanol over different ZSM-5 catalysts at a reaction temperature of 200°C.

[0216] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 200° C. The observed space-time yields of the ether product are provided in Table 2.

[0217] Table 2

[0218]

[0219] SAR indicates the silica:alumina molar ratio of the zeolite

[0220] The results in Table 2 show that the use of ethyl formate enhances the space-time yield of diethyl ether.

[0221] Example 3

[0222] This example demonstrates the effect of ethyl butyrate on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0223] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 3.

[0224] Table 3

[0225]

[0226] SAR indicates the silica:alumina molar ratio of the zeolite

[0227] The results in Table 3 show that the use of ethyl n-butyrate enhances the space-time yield of diethyl ether.

[0228] Example 4

[0229] This example demonstrates the effect of dimethyl adipate on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0230] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 4.

[0231] Table 4

[0232]

[0233] SAR indicates the silica:alumina molar ratio of the zeolite

[0234] The results in Table 4 show that the use of dimethyl adipate enhances the space-time yield of diethyl ether.

[0235] Example 5

[0236] This example demonstrates the effect of 5-nonanone on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0237] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 5.

[0238] Table 5

[0239]

[0240] SAR indicates the silica:alumina molar ratio of the zeolite

[0241] The results in Table 5 show that the space-time yield of diethyl ether is enhanced using 5-nonanone.

[0242] Example 6

[0243] This example demonstrates the effect of acetone on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0244] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 6.

[0245] Table 6

[0246]

[0247] SAR indicates the silica:alumina molar ratio of the zeolite

[0248] The results in Table 6 show that the use of acetone enhances the space-time yield of diethyl ether.

[0249] Example 7

[0250] This example demonstrates the effect of 1,1-diethoxyethane on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0251] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 7.

[0252] Table 7

[0253]

[0254] SAR indicates the silica:alumina molar ratio of the zeolite

[0255] The results in Table 7 show that the use of 1,1-diethoxyethane enhances the space-time yield of diethyl ether.

[0256] Example 8

[0257] This example demonstrates the effect of benzaldehyde on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0258] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 8.

[0259] Table 8

[0260]

[0261] SAR indicates the silica:alumina molar ratio of the zeolite

[0262] The results in Table 8 show that the use of benzaldehyde enhances the space-time yield of diethyl ether.

[0263] Example 9

[0264] This example demonstrates the effect of n-butyraldehyde on the dehydration reaction of ethanol over different ZSM-5 catalysts.

[0265] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 9.

[0266] Table 9

[0267]

[0268] SAR indicates the silica:alumina molar ratio of the zeolite

[0269] The results in Table 9 show that the use of n-butyraldehyde enhances the space-time yield of diethyl ether.

[0270] Example 10

[0271] This example demonstrates the effect of benzaldehyde on the dehydration reaction of n-hexanol over ZSM-5 catalyst.

[0272] The dehydration reaction of n-hexanol was carried out using the general reaction method and apparatus II described above. -1 The liquid feed was introduced into the reactor at a constant flow rate to achieve 10 mL mL cat -1 h -1 The reactor was installed in a downflow configuration. Liquid samples were analyzed by off-line gas chromatography (GC) at 3.5 h time of production (ToS).

[0273] At 3.5 h ToS, the liquid feed was changed to a liquid feed consisting of 1 mol % benzaldehyde (1.06 g) in n-hexanol (101.14 g); all other variables remained the same. At 5.5 h ToS, liquid samples were analyzed by off-line GC. The observed space-time yields of dihexyl ether and hexene products are provided in Table 10.

[0274] Table 10

[0275]

[0276] The results in Table 10 show the enhancement of the space-time yield of dihexyl ether using benzaldehyde.

[0277] Embodiment 11

[0278] This example demonstrates the effect of 4-trifluorobenzaldehyde on the dehydration reaction of n-hexanol over ZSM-5 catalyst.

[0279] The dehydration reaction of n-hexanol was carried out using the general reaction method and apparatus II described above. -1 The liquid feed was introduced into the reactor at a constant flow rate to achieve 10 mL mL cat -1 h -1 The reactor was installed in a downflow configuration. Liquid samples were analyzed by off-line gas chromatography (GC) at 4.25 h time of production (ToS).

[0280] At 4.25 h ToS, the liquid feed was changed to a liquid feed consisting of 1 mol % 4-fluorobenzaldehyde (1.746 g) in n-hexanol (101.14 g); all other variables remained the same. At 6.25 h ToS, a liquid sample was analyzed by off-line GC. The observed space-time yields of dihexyl ether and hexene products are provided in Table 11.

[0281] Table 11

[0282]

[0283] The results in Table 11 show that the space-time yield of dihexyl ether is enhanced using 4-trifluorobenzaldehyde.

[0284] Example 12

[0285] This example demonstrates the effect of ethyl formate on the dehydration of ethanol over ZSM-5 and ZSM-11 catalysts at a reaction temperature of 150°C.

[0286] The ethanol dehydration reaction was carried out using the general reaction method and apparatus I described above at a reaction temperature of 150° C. The observed space-time yields of the ether product are provided in Table 12.

[0287] Table 12

[0288]

[0289] SAR indicates the silica:alumina molar ratio of the zeolite

[0290] The results in Table 12 show that the use of ethyl formate enhances the space-time yield of diethyl ether.

Claims

1. A process for dehydrating C2+ alcohols to ether products in the presence of a catalyst and a co-catalyst, wherein The catalyst is at least one aluminosilicate zeolite catalyst, and the aluminosilicate zeolite catalyst is a medium-pore zeolite with a three-dimensional framework structure. wherein the zeolite has a maximum pore opening defined by 10 T atoms in tetrahedral coordination, and wherein the aluminosilicate zeolite catalyst is selected from the group consisting of TON, MTT, FER, MWW, MFI, EUO, MEL, MFS and TER; and The co-catalyst is one or more compounds selected from the following: (i) Formula R A1 CHO (Formula I) aldehyde, wherein R A1 is hydrogen, C1-C5 alkyl, or optionally substituted phenyl; (ii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is a C1-C5 alkyl group; (iii) Formula R E1 CO2R E2 (Formula III) wherein R E1 is hydrogen or C1-C5 alkyl and R E2 is a C1-C5 alkyl group; and (iv) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is a C1-C5 alkyl group; and The molar ratio of the cocatalyst to the C2+ alcohol is maintained at less than 1.

2. The process according to claim 1, wherein the aluminosilicate zeolite catalyst is a framework type MFI.

3. The process according to claim 2, wherein the aluminosilicate zeolite catalyst is ZSM-5.

4. The process of claim 1, wherein the aluminosilicate zeolite catalyst is a framework type MEL.

5. The process according to claim 4, wherein the aluminosilicate zeolite catalyst is ZSM-11.

6. The method of claim 1, wherein the aluminosilicate zeolite is composited with a binder material.

7. The method of claim 1, wherein the C2+ alcohol to be dehydrated is a primary alcohol comprising a C2-C6 alkyl group and a hydroxyl group.

8. The method according to claim 1, wherein the C2+ alcohol to be dehydrated is one or more alcohols selected from ethanol, n-propanol and n-butanol.

9. The method of claim 1, wherein the C2+ alcohol to be dehydrated is a single C2+ alcohol species.

10. The process of claim 1, wherein the molar ratio of the co-catalyst to the C2+ alcohol is maintained in the range of 0.00001:1 to 0.2:

1.

11. The process of claim 1 , wherein the promoter is generated in situ in the dehydration process.

12. The method of claim 1, wherein the method is performed at a temperature of 100°C to 300°C.

13. The process of claim 1, wherein the process is performed as a heterogeneous gas phase process.

14. A method for improving the productivity of ether products in a process for dehydrating C2+ alcohols in the presence of a catalyst and a co-catalyst, wherein the catalyst is at least one aluminosilicate zeolite catalyst, the aluminosilicate zeolite catalyst being a medium-pore zeolite having a 3-dimensional framework structure, wherein the zeolite has a maximum pore opening defined by 10 T atoms in tetrahedral coordination, wherein the aluminosilicate zeolite catalyst is selected from the group consisting of TON, MTT, FER, MWW, MFI, EUO, MEL, MFS and TER; and The co-catalyst is one or more compounds selected from the following: (i) Formula R A1 CHO (Formula I) aldehyde, wherein R A1 is hydrogen, C1-C5 alkyl, or optionally substituted phenyl; (ii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is a C1-C5 alkyl group; (iii) Formula R E1 CO2R E2 (Formula III) wherein R E1 is hydrogen or C1-C5 alkyl and R E2 is a C1-C5 alkyl group; and (iv) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is a C1-C5 alkyl group, and the molar ratio of the cocatalyst to the C2+ alcohol is maintained at less than 1.

15. Use of a cocatalyst in a process for catalytically dehydrating a C2+ alcohol to an ether product to improve the productivity of the ether product, wherein The catalyst is at least one aluminosilicate zeolite catalyst, and the aluminosilicate zeolite catalyst is a medium-pore zeolite with a three-dimensional framework structure. wherein the zeolite has a maximum pore opening defined by 10 T atoms in tetrahedral coordination, wherein the aluminosilicate zeolite catalyst is selected from the group consisting of TON, MTT, FER, MWW, MFI, EUO, MEL, MFS and TER; and The co-catalyst is one or more compounds selected from the following: (i) Formula R A1 CHO (Formula I) aldehyde, wherein R A1 is hydrogen, C1-C5 alkyl, or optionally substituted phenyl; (ii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is a C1-C5 alkyl group; (iii) Formula R E1 CO2R E2 (Formula III) wherein R E1 is hydrogen or C1-C5 alkyl and R E2 is a C1-C5 alkyl group; and (iv) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 The same or different and each is a C1-C5 alkyl group, and the molar ratio of the cocatalyst to the C2+ alcohol is maintained at less than 1.

16. A process for dehydrating C2+ alcohols to ether products in the presence of a catalyst, wherein The catalyst is at least one aluminosilicate zeolite catalyst, and the aluminosilicate zeolite catalyst is a medium-pore zeolite with a three-dimensional framework structure. wherein the zeolite has a maximum pore opening defined by 10 T atoms in tetrahedral coordination, wherein the aluminosilicate zeolite catalyst is selected from the group consisting of TON, MTT, FER, MWW, MFI, EUO, MEL, MFS and TER; and Wherein before using the catalyst in the dehydration method, the catalyst has been impregnated with a promoter, the promoter being a compound selected from the following: (i) Formula R A1 CHO (Formula I) aldehyde, wherein R A1 is hydrogen, C1-C5 alkyl, or optionally substituted phenyl; (ii) Formula R K1 COR K2 A ketone of formula II, wherein R K1 and R K2 The same or different and each is a C1-C5 alkyl group; (iii) Formula R E1 CO2R E2 (Formula III) wherein R E1 is hydrogen or C1-C5 alkyl and R E2 is a C1-C5 alkyl group; and (iv) Formula R E1 (CO2R E2 )2 (Formula IV) of the diester, wherein R E1 and R E2 are the same or different and are each a C1-C5 alkyl group; and The molar ratio of the co-catalyst to the C2+ alcohol is maintained at less than 1.

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