WO2017005719A1

WO2017005719A1 - Modified crystalline aluminosilicate for dehydration of alcohols

Info

Publication number: WO2017005719A1
Application number: PCT/EP2016/065769
Authority: WO
Inventors: Nikolai Nesterenko; Colin DUPONT; Delphine Minoux; Jean-Pierre Dath; Vincent Coupard
Original assignee: Total Research & Technology Feluy; IFP Energies Nouvelles
Priority date: 2015-07-09
Filing date: 2016-07-05
Publication date: 2017-01-12

Abstract

A method for the transformation of an alcohol into an olefin which comprises contacting said alcohol with a solid catalyst which comprises a zeolitic material of the FER type framework possessing a network of micropores which contains mesopores that are connected to the micropores, wherein the zeolitic material has a ratio of the volume of the mesopores contained within the network of micropores to the volume of the micropores in the range 0.1 to 2.

Description

MODIFIED CRYSTALLINE ALUMINOSILICATE FOR DEHYDRATION OF ALCOHOLS

TECHNICAL FIELD

The present invention relates generally to the field of dehydration of alcohols on acidic catalysts to make corresponding olefins, preferably of alcohols having at least two carbon atoms for the production of olefins having the same number of carbon atoms as the alcohols. The present invention relates to a catalyst composition comprising a mesoporous crystalline aluminosilicate of the group FER (Framework Type FER) and to a process for the preparation thereof. The present invention also relates to the use of said catalyst composition in a dehydration process of alcohols and to the use of the olefins so-produced in various subsequent processes.

BACKGROUND OF THE INVENTION

The dehydration reactions of alcohols to produce alkenes have been known for a long time. Solid acid catalysts are widely used for alcohol dehydration and the conversion of alcohols therewith is nearly complete. However, in view of the potential downstream applications of olefins, it is of particular importance to limit the amount of secondary products and insure a stable catalyst performance to gain in process efficiency and to save expensive steps of downstream separation/purification as well as to recover the catalyst activity by regeneration.

Dehydration of ethanol was described in WO201 1/089235. The process for the dehydration of ethanol to ethylene was carried out in presence of zeolite catalysts and provides an alternative route to ethylene from biobased products if ethanol is obtained by fermentation of carbohydrates.

Dehydration of isobutanol to corresponding olefins brings a perspective route to produce the renewable feedstock for petrochemicals and refining applications. Unfortunately, the direct conversion of isobutanol over a conventional dehydration catalyst, for example on alumina, leads to a product rich in isobutene. Not isobutene but linear butenes are often interesting as feedstock for metathesis, sulfuric acid catalyzed alkylation, oligomerization, for the use as a co-polymer or for the integration into the Raffinate I - pool (definition of raffinate I can be found in US4282389). Therefore, one-pot process for converting isobutanol into linear butenes rich effluentis desired. "Linear butenes" means but-1 -ene and but-2-ene.

While many skeletal isomerisation catalysts for the conversion of n-butenes into isobutene have been developed, the reverse skeletal isomerisation of isobutene into n-butenes has been rarely mentioned (Petkovic et al., J. Catal., 2000, 191 , 1 ; Zhong et al., Appl. Catal. A, 201 1 , 403, 1 ). Most of the active and selective catalysts are unidirectional 10-membered ring zeolites. WO2011/1 13834 relates to the simultaneous dehydration and skeletal isomerisation of isobutanol on acid catalysts. The process discloses the contact of a stream comprising isobutanol with a catalyst able to make such reaction. The catalyst was a crystalline silicate, a dealuminated crystalline silicate, or phosphorus modified crystalline silicate having Si/AI higher than 10; or silicoaluminaphosphate molecular sieve, or a silicated, zirconated or titanated or fluorinated alumina. The conversion of isobutanol was almost complete with selectivity in butenes ranging from 95 wt% to 98 wt%. The selectivity in isobutene was around 41 -43%.

However, the authors suggested FER with Si/AI ratio of at least 10 was required to avoid excessive by- products formation. Dealumination of FER with Si/AI ratio below 10, by combination of steaming and acid leaching is not an option as it leads to a loss of selectivity towards linear butenes. In addition, FER with Si/AI ratio of at least 10 can only be prepared using an organic templating agent, which results in significantly increased production costs.

US 2014/0296596 discloses a mesostructured material comprising zeolitic entities in the wall of said mesostructured material

Dazhi Zhang et al. in Applied Catalysis A : General 403 (201 1 ) 1 -1 1 disclose the use of a ferrierite catalyst for the dehydration of n-butanol into iso-butene. The ferrierite catalyst is used without further treatment.

WO 2011/1 13834 discloses the simultaneous dehydration and skeletal isomerisation of isobutanol into n- butane over a ferrierite catalyst being used without further treatment.

The mesoporous FER zeolites disclosed here, obtained either via desilication under hydrothermal conditions in presence of alkali carbonate or via a selective pseudo-solid desilication-recrystallization method based on a solvent-free route using hydrated metal ion carbonate in the presence or in the absence of organic structure directing agent, have the same properties. As per catalytic ability to dehydrate alcohols and isomerizes the resulting olefins, there is no reason to differentiate mesoporous FER upon their method of preparation as long as their morphology, topology and chemical composition are similar. SUMMARY OF THE INVENTION

It is an object of the present invention to provide catalyst compositions exhibiting substantially complete once-through conversion of alcohols into olefins.

Another object of the present invention is to provide catalyst compositions showing good to excellent selectivity to linear olefins, above thermodynamic equilibrium, in simultaneous dehydration and skeletal isomerization reaction of alcohols having at least four carbon atoms.

It is a further object of the present invention to provide catalyst compositions that can be easily regenerated.

According to a first aspect, the invention discloses a method for the transformation of an alcohol or a composition comprising at least one alcohol into the respective corresponding olefin which comprises contacting said alcohol with a solid catalyst which comprises a zeolitic material of the FER type framework possessing a network of micropores which contains mesopores that are connected to the micropores, wherein the zeolitic material has a ratio of the volume of the mesopores contained within the network of micropores to the volume of the micropores in the range 0.1 to 2.5 preferably 2.

Micropore and mesopore volumes can for instance be measured via N2 adsorption. Preferably the ASTM method D4365 can be used to measure said micropore and mesopore volumes.

Connection of the mesopores to the micropores can be for instance verified via SEM measurement.

Preferably, the zeolitic material of the FER type framework possesses an ordered two-dimensional (2D) network of micropores (ie pores < 2nm in diameter) containing mesopores (pores with diameter in the range 2-50nm) connected to the micropores, the mesopores having an aspect ratio (length to width) higher than 2 and an orientation of the mesopores in the direction of the mbropores.

The FER type framework is advantageously selected among ferrierite, FU-9 and ZSM-35.

The mesoporized zeolitic material according to the first aspect of the invention possesses advantageously a Si/AI ratio higher than 5 and lower than 10, preferably between 6 and 9.

According to the first aspect of the invention, the alcohol (or a mixture of alcohols) is contacted with the solid catalyst at a temperature comprised between 100 and 560°C, preferably between 250 and 400°C, with a WHSV of at least 1 h-1 , preferably comprised between 1 and 30h-1 , preferably between 2 and 15h- 1 and a pressure comprised between 1 and 20barg, preferably between 1 and 10barg.

A preferred alcohol is selected among C2, C3, C4, C5, C6 and C7 alcohols and their mixtures. The nomenclature CX where X is a figure refers to an alkyl chain with X carbon atoms. More precisely, a CX alcohol is an alcohol having X carbon atoms.

More preferably, the alcohol is selected among ethanol, propan-1 -ol, propan-2-ol, 2-methyl-propan-1 -ol, butan-2-ol, butan-1 -ol, 2-methyl-propan-2-ol and their mixtures, eventually in the presence of water.

The method according to the first aspect of the invention results in the alcohol or a mixture of alcohols starting material and the olefin product carry the same number of carbon atoms in their backbone. As a matter of example, ethanol shall result in ethylene product, propanol shall result in propylene, isobutanol (i.e. 2 methyl propan-1 -ol) shall result in but-l ene and/or but-2-ene and/or isobutene.

The use of a method according to the first aspect of the invention is suitable for the preparation of a linear olefin starting from a branched alcohol or respectively the preparation of linear olefins from a mixture of branched alcohols. According to a second aspect the invention discloses a process for the simultaneous dehydration and skeletal isomerisation of a branched alcohol(s) to make substantially corresponding olefins, having the same number of carbons and consisting essentially of a mixture of n-olefins and branched olefins, said process comprising:

a) introducing in a reactor a stream (A) comprising the branched alcohol(s), optionally water, optionally an inert component,

b) contacting said stream with a catalyst in said reactor at conditions effective to dehydrate and skeletally isomerize at least a portion of the branched alcohol(s) to produce n-olefins and branched olefins,

c) recovering from said reactor a stream (B), comprising removing water, the inert component if any and unconverted branched alcohol(s) if any to get a mixture of n-olefins (i.e. linear olefins) and branched olefins,

wherein the WHSV of the branched alcohol is at least 1 h-1 and the catalyst is capable to make simultaneously the dehydration and skeletal isomerization of olefins and wherein the catalyst contains a mesoporous crystalline silicate of the FER type framework, having a ratio of the volume of the intracrystalline mesopores to the volume of the micropores in the range of 0.1 to 2.5 preferably 2.

A mesoporous crystalline silicate of the FER type framework is a FER type material having pores with a size between 2 to 50 nm. Freshly synthesized FER does not contain any mesoporosity. The mesoporosity of FER has to be generated via for instance one of the method described in this specification. Presence of mesoporosity can be evidenced for instance by measuring the ratio of the volume of the intracrystalline mesopores to the volume of the micropores via for instance BET N2 adsorption measurement.

According to its second aspect, the zeolitic material of the FER type framework possesses a network of micropores (ie pores < 2nm in diameter) containing mesopores (pores with diameter in the range 2-50nm) connected to the micropores, and a ratio of the volume of the intracrystalline mesopores to the volume of the micropores in the range 0.1 to 2.

Skeletal isomerization results in an increase of the amount of linear olefins and a decrease of the amount of branched olefins when the process according to the second aspect of the invention is carried out.

According to its second aspect, said branched alcohol is preferably iso butanol and said corresponding olefins is a linear C4 olefin.

A catalyst composition or catalyst (both expression being equivalent) is provided. Said catalyst composition comprises a mesoporous crystalline aluminosilicate of the Framework Type FER characterized in that it exhibits a unique distribution of oriented 3D cylinder like mesopores (pores with diameters in the range 2- 50 nm) obtained by the selective dissolution of the crystal of the FER type zeolite along both the 8- ([010]) and 10-MR ([001]) channel directions, the mesopores being connected to the microporores, having an aspect ratio (length to width) higher than 2, a ratio of the volume of the intracrystalline mesopores to the volume of the mbropores in the range 0.1 to 2, and an orientation of the mesopores in the direction of the micropores.

In a preferred embodiment, the mesoporized crystalline aluminosilicate is a mesoporized crystalline ferrierite.

A dehydration process of alcohols for the production of a mixture of olefins is herein provided. Said process comprises the steps of:

(A) providing an alcohol having at least two carbon atoms, and preferably at most 7 carbon atoms, or mixture thereof with the proviso that the alcohols contained in the mixture have the same number of carbon atoms, or optionally the alcohols contained in the mixture have a different number of carbon atoms,

(B) introducing in a reactor a stream (S1 ) comprising said alcohols, and optionally water and optionally an inert component,

(C) contacting said stream (S1 ) with a catalyst composition according to the present invention under conditions suitable for producing a mixture of corresponding olefins having the same number of carbon atoms as the alcohol, and

(D) recovering from said reactor a stream (S2), optionally removing water and the inert component and if any unconverted alcohol and other oxygenated compounds to get a mixture of olefins having the same number of carbon atoms as said alcohol.

In a particular embodiment, step (C) may also be carried out under conditions suitable for producing a mixture of corresponding olefins having the same number of carbon atoms as the alcohol, and suitable for simultaneous skeletal isomerisation, for example when the alcohol has at least four carbon atoms.

Preferably, said alcohol may be selected from C2-C7 alkyl substituted by one hydroxyl group or mixture thereof with the proviso that the alcohols contained in the mixture have the same number of carbon atoms. Preferably, said mixture of alcohols may comprise alcohols having at least three carbon atoms, more preferably at most seven carbon atoms. For example, said alcohol may be a mixture of isobutanol and n-butanol.

In particular, the present process is suitable for the production of olefins from alcohols having two, three or four carbon atoms, preferably for the production of linear butenes from isobutanol. The present process allows a substantially complete once-through conversion of alcohols to corresponding olefins having the same number of carbon atoms by eliminating or poisoning the unselective catalytic acid sites. The invention is suitable for converting a mixture of alcohols to produce a mixture of olefins being afterward separated.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates in part to a catalyst composition comprising a mesoporous crystalline aluminosilicate of the Framework Type FER characterized in that it exhibits a unique distribution of oriented 3D cylinder like mesopores (pores with diameters in the range 2- 50 nm) obtained by the selective dissolution of the crystal of the FER type zeolite along both the 8- ([010]) and 10-MR ([001 ]) channel directions, the mesopores being connected to the microporores, having an aspect ratio (length to width) higher than 2, a ratio of the volume of the intracrystalline mesopores to the volume of the micropores in the range 0.05 to 2, an intracrystalline mesoporous volume above 0.02mL/g and an orientation of the mesopores in the direction of the micropores.

In a preferred embodiment, the Framework Type FER is a crystalline aluminosilicate containing advantageously at least one 10 members ring into the structure based on T-atoms, i.e. on the Al and Si atoms contained in said ring. The family of Framework Type FER includes Ferrierite, [B-Si-0]-FER, [Ga- Si-0]-FER, [Si-0]-FER, FU-9, ISI-6, Monoclinic ferrierite, NU-23, Sr-D, ZSM-35.

In a more preferred embodiment, the modified crystalline aluminosilicate of the Framework Type FER is selected from Ferrierite, FU-9, Nu-23, ISI-6, ZSM-35 and SUZ-4. Preferably, the modified crystalline aluminosilicate of the Framework Type FER is Ferrierite.

The term "intracrystalline mesopore" as used herein corresponds to mesopores which are located within a zeolite crystal.

The term "intercrystalline mesopore" as used herein corresponds to mesopores which are located between zeolite crystals.

In a preferred embodiment, the parent crystalline crystalline aluminosilicate of the FER framework is such that the Si/AI ratio ranges more advantageously from 5 to 100, preferably from 7 to 90, more preferably from 7 to 55. If one consider economical requirements, it is preferable to use cheaper parent FER zeolite having Si/AI ratio lower than10.

A process for the preparation of the catalyst composition or catalyst is provided. Said process comprises the steps of: (a) contacting a crystalline aluminosilicate of the Framework Type FER with a first metal ion carbonate, to obtain a first composition, and

(b) heating said first composition in a vessel at a temperature sufficient to increase the pressure above the atmospheric pressure in said vessel or at a pressure of at least 2 bara and at a temperature of at least 80°C, wherein the total amount of water of said first composition originating from the crystalline aluminosilicate of the Framework Type FER and fromthe first metal ion carbonate is greater or equal to 4 mol per mol of metal ion carbonate, and wherein the first composition obtained at step (a) is not a suspension in water and is under solid state at standard temperature and pressure (STP) before the performance of step (b).

The unit "bara" refers to "bar absolute". Measurement of the pressure can be "absolute" or "relative". Relative pressure is made by comparison with the atmospheric pressure. It is the measure made by most nanometers; when the nanometer indicates zero the pressure is equal to the atmospheric pressure. On the other hand, the absolute pressure is the pressure usually used in thermodynamic. The difference between the relative and the absolute pressure is the atmospheric pressure (1 bar).

Preferably said first metal ion carbonate is a single metal ion carbonate or a mixture of at least two different metal ion carbonates. Preferably said first metal ion carbonate is chosen in order to result in water alkalinization, when placed in degassed distilled water (i) at atmospheric pressure or under pressure in a closed vessel in the presence of a neutral gas such as nitrogen or argon, and (ii) at room temperature and/or at boiling water temperature. Preferably said first metal ion is ammonium, sodium or potassium ion.

Preferably said first metal ion carbonate is chosen among Na2C03, NaHC03 or K2C03 or any mixture thereof. Preferably, the heating of step (b) allowing the formation of the mesporized crystalline aluminosilicate of the Framework Type FER according to the present invention is performed at a temperature from 100 to 150°C, preferably from 120 to 140°C, more preferably at 130°C, under a pressure from 2 to 20bara, preferably between 2 and 15bara said pressure being preferably autogenously generated.

Preferably, an organic templating agent is added at step (a) of the process for the preparation of the catalyst composition said organic templating agent being preferably recyclable. Another process for the preparation of the catalyst composition is provided. Said process comprises the steps of:

(a) contacting parent crystalline aluminosilicate of the Framework Type FER with a basic aqueous solution containing at least one weak base i.e. a base having a pKa of at least 7 preferably at least 9, preferably an alkaline metal carbonate, at a concentration ranging from 1 M to 2M, preferably between 1.25M to 2M, to obtain a first composition,

(b) heating said first composition in a vessel at a temperature sufficient to increase the pressure above the atmospheric pressure in said vessel or at a pressure of at least 2 bara and at a temperature of at least 100°C or at a temperature from 100 to 150°C, preferably from 120 to 150°C, more preferably from 130°C to 150°C, under pressure from 2 to 20bara, preferably between 2 and 15bara said pressure being preferably autogenously generated,

(c) filtering off the zeolite obtained at step (d)

washing it with a solvent, especially a polar solvent, for example pure distilled water, to obtain a washed zeolite,

wherein optionally the ratio of said parent zeolitic material to said basic aqueous solution in said first composition ranges from 0.02 to 0.05 g/mL, preferably 0.03 to 0.04 g/mL and is most preferably of 0.0334 g/mL

A further process for the preparation of the catalyst composition is provided. Said process comprises the steps of:

(a) contacting a parent crystalline aluminosilicate of the Framework Type FER with a basic aqueous solution containing at least a strong base i.e. a base that is totally dissociated in water such as an alkaline hydroxide base at a concentration ranging from 0.2M to 0.3M, more preferably at 0.25M, to obtain a first composition,

(b) heating said first composition in a vessel at a temperature sufficient to increase the pressure above the atmospheric pressure in said vessel or at a pressure of at least 2 bara and at a temperature of at least 100°C or at a temperature from 100 to 150°C, preferably from 120 to 140°C, more preferably at 130°C, under a pressure from 2 to 20bara, preferably between 2 and 15bara said pressure being preferably autogenously generated,

(c) filtering off the zeolite obtained at step (g)

Preferably, the process for the preparation of the mesoporized crystalline aluminosilicate of the Framework Type FER according to the present invention may comprise one or more of the following steps after step (b) of the above process described: (i) water washing the composition resulting of step (b) or step (e) or step (h) to obtain a washed composition.

(ii) ion exchange of said washed composition of step (i) to obtain an ion-exchanged composition.

(iii) drying of ion-exchanged composition of step (ii) to obtain dried ion-exchanged material, wherein the drying is performed at temperature ranging from 50°C to 200°C for a period ranging from 30min to 24h, preferably from 1 h to 15h.

(iv) calcination of dried ion-exchanged composition of step (iii) to obtain a calcinated composition, wherein calcination is performed at a temperature from 400 to 800°C, preferably from 500 to 600°C, more preferably at 550°C, under a stream of air or neutral gas such as nitrogen or argon. Preferably, the calcining step is carried out subsequently to the drying step.

The step (ii) of applying ion exchange may be carried out by contacting said mesoporized crystalline aluminosilicate with a solution containing one or more inorganic salts such as inorganic ammonium salt, inorganic calcium salt, inorganic lithium salt, inorganic sodium salt, inorganic potassium salt, inorganic magnesium salt or inorganic silver salt. Inorganic salt may be salt of nitric acid, halogenic acid, sulfuric acid, sulfurous acid, nitrous acid or mixture thereof, preferably nitric acid or halogenic acid or mixture thereof. The concentration of each inorganic salt in said solution may range from 1.10-4M to 10M, preferably from 1.10-3M to 1 M. Step (ii) may be carried out at temperature ranging from 10°C to 110°C, preferably from 20°C to 80°C, preferably for 30 min to 24h, more preferably for 1 h to 10h. Preferably, the solution may contain ammonium salt, calcium salt or lithium salt of nitric acid or halogenic acid. Acceptable halogenic acids include hydrochloric and hydrobromb acids

Optionally, the process for the preparation of the mesoporized crystalline aluminosilicate of the Framework Type FER according to the present invention may also comprise an additional treatment in an acidic medium by contacting said crystalline aluminosilicate of the Framework Type FER, provided of step (i) with a solution, preferably an aqueous solution, containing one or more organic compounds, each organic compound comprising one or more -C02H, -S03H or -S04H groups or salts thereof, preferably two or more -C02H, -S03H or -S04H groups or salts thereof. Without willing to be bound by theory this step may allow the removal of non-selective acid sites in said mesoporized crystalline aluminosilicate. Preferably, the solution contains one or more organic compounds, each comprising one or more -C02H groups or salts thereof, preferably two or more -C02H groups or salts thereof. More preferably, the solution contains one or more organic compounds selected from the group consisting of citric acid, maleic acid, ethylenediaminetetracetic acid, tartaric acid, fumaric acid, oxalic acid, malonic acid, succinic acid, adipic acid, glutaric acid or itaconic acid, phtalic acid, isophtalic acid, nitrilotriacetic acid, hydroxyethylenediaminetriacetic acid, or salts thereof or mixture thereof. More preferably, said solution comprises citric acid, maleic acid, tartaric acid or ethylenediaminetetracetic acid or salts thereof or mixture thereof. The concentration in each one or more organic compounds in said solution may range from 1.10- 4M to 10M, preferably from 1 .10-3M to 1 M. Step (i) may be carried out at temperature ranging from 10°C to 1 10°C, preferably from 20°C to 80°C, preferably from 30 min to 24h, more preferably from 1 h to 12h.

In another specific embodiment, the catalyst composition may comprise a binder, preferably an inorganic binder. The binder is selected so as to be resistant to the temperature and other conditions employed in the dehydration process of the invention. The binder is an inorganic material selected from clays, silica, metal silicate, metal oxides (such as Zr02), alumina, aluminophosphate binders, in particularly, stoichiometric amorphous aluminophosphate or gels including mixtures of silica and metal oxides. It is desirable to provide a catalyst having good crush strength. This is because in commercial use, it is desirable to prevent the catalyst from breaking down into powder-like materials. Such clay or oxide binders have been employed normally only for the purpose of improving the crush strength of the catalyst. Preferably, said binder is selected from the group consisting of clays, alumina, silica-alumina, silica, titania, aluminophosphate, titan ia-silica. A particularly preferred binder for the catalyst composition of the present invention is silica. The relative proportions of the finely divided modified crystalline aluminosilicate material and the inorganic oxide matrix of the binder can vary widely. Typically, the binder content may range from 5 to 95% by weight, more typically from 20 to 85% by weight, based on the weight of the catalyst composition. By adding a binder to the catalyst composition, this latter may be formulated into pellets, extruded into other shapes, or formed into spheres or a spray-dried powder.

Said binder may be mixed to the mesoporized crystalline aluminosilicate or to the crystalline aluminosilicate, i.e. prior or subsequently to step (ii) of the present process. Typically, the binder and the crystalline aluminosilicate, modified or not, are mixed together by a mixing process. In such a process, the binder, for example silica, in the form of a gel is mixed with the crystalline aluminosilicate, modified or not. The resultant mixture is extruded into the desired shape, for example cylindrical or multi-lobe bars. Spherical shapes can be made in rotating granulators or by oil-drop technique. Small spheres can further be made by spray-drying a catalyst-binder suspension. Thereafter, the extruded material containing the binder and the crystalline aluminosilicate, modified or not, is calcined in air or an inert gas, typically at a temperature of from 200 to 900°C for a period of from 1 to 48 hours. Preferably, said binder is selected from the group consisting of clays, alumina, silica-alumina, silica, titania, aluminophosphate, titan ia-silica. Hence, according to the present process, the crystalline aluminosilicate provided in step (A) may encompass the extruded material containing the binder and the crystalline aluminosilicate as described herein.

The modified crystalline aluminosilicate may be in H-form. The H-form of a modified crystalline aluminosilicate of the Framework Type FER means that it comprises oxygen atoms bonded to one aluminium atom and one silicon atom, and which is protonated with a hydrogen atom, resulting in the following sequence -[-Al-0(H)-Si-]-. In the present invention, the mesoporized crystalline aluminosilicate may be essentially under H-form, which means containing less than 1000 ppm of the total amount of the alkali ions and the alkaline earth ions. In another embodiment, the modified crystalline aluminosilicate is partly under H-form. It means that in said modified crystalline aluminosilicate part of the hydrogen atoms bonded to oxygen atoms in the following sequence -[-Al-0(H)-Si-]- is substituted by metallic ions, preferably alkali ions, alkaline earth ions or silver ions. In a preferred embodiment, the modified crystalline aluminosilicate comprises the sequences -[-Al-0(H)-Si-]- and -[-Al-0(X)-Si-]- wherein X is alkali ions, alkaline earth ions or silver ions, the sequence -[-Al-0(X)-Si-]- representing less than 75% wt based on the total amount of sequences -[-Al-0(H)-Si-]- and -[-Al-0(X)-Si-]- in said modified crystalline aluminosilicate, preferably the sequence -[-Al-0(X)-Si-]- represents less than 50% wt, more preferably less than 25% wt, and preferably at least 1 % wt, more preferably at least 5% wt, most preferably at least 10%. Preferably, the alkali ions or alkaline earth ions may be Na, K, Cs, Li, Mg or Ca.

Alternatively, the modified crystalline aluminosilicate may have content in one of the elements selected from the group consisting of lithium, sodium, cesium, magnesium, calcium, potassium and silver, independently from one another, ranging from 10 to 10000 ppm, preferably ranging from 10 to 5000 ppm, more preferably ranging from 10 to 3000 ppm, most preferably ranging from 10 to 2000 ppm.

The present invention also provides a dehydration process of a composition comprising at least one alcohol or a mixture of alcohols for the production of a mixture of olefins comprising the steps of:

(A) providing an alcohol having at least two carbon atoms, and preferably at most 7 carbon atoms, or mixture thereof with the proviso that the alcohols contained in the mixture have the same number of carbon atoms,

(B) introducing in a reactor a stream (S1 ) comprising said alcohol, and optionally water and optionally an inert component,

(C) contacting said stream (S1 ) with a catalyst composition according to the present invention under conditions suitable for producing a mixture of olefins having the same number of carbon atoms as the alcohol,

(D) recovering from said reactor a stream (S2), optionally removing water and the inert component and if any unconverted alcohol to get a mixture of olefins having the same number of carbon atoms as the alcohol.

In a particular embodiment, step (C) may also be carried out under conditions suitable for producing a mixture of corresponding olefins having the same number of carbon atoms as the alcohol, and suitable for simultaneous skeletal isomerisation, for example when the alcohol is a mixture of alcohol having at least four carbon atoms.

Preferably, the alcohol has at least two carbon atoms and at most 7 carbon atoms. Preferably, the alcohols are provided from biomass fermentation or biomass gasification to syngas followed by a modified Fischer-Tropsch synthesis. Preferably, said alcohol may be selected from C2-C7 alkyl substituted by one hydroxyl group or mixture thereof with the proviso that the alcohols contained in the mixture have the same number of carbon atoms. Whenever the term "substituted" is used in the present invention, it is meant to indicate that one or more hydrogen on the atom indicated in the expression using "substituted" is replaced with a selection from the indicated group, provided that the indicated atom's normal valence is not exceeded, and that the substitution results in a chemically stable compound, i.e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture. The term "alkyl" by itself or as part of another substituent refers to a hydrocarbyl radical of formula CnH2n+1 wherein n is a number between 2 and 7.

Preferably, the alcohol may be ethanol, propanol, isopropanol, 1 -butanol, 2-butanol, isobutanol (2 methyl propanol), pentan-1 -ol, 3-Methylbutan-1 -ol, 2-Methylbutan-1 -ol, 2,2-Dimethylpropan-1 -ol, pentan-3-ol, Pentan-2-ol, 3-Methylbutan-2-ol, 2-Methylbutan-2-ol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methylpentan-1 - ol, 3-methylpentan-1 -ol, 4-methylpentan-1 -ol, 2-methylpentan-2-ol, 3-methylpentan-2-ol, 4-methylpentan- 2-ol, 2-methylpentan-3-ol, 3-methylpentan-3-ol, 2,2-dimethylbutan-1 -ol, 2,3-dimethylbutan-1 -ol, 3,3- dimethylbutan-1 -ol, 2,3-dimethylbutan-2-ol, 3,3-dimethylbutan-2-ol or 2-ethylbutan-1 -ol, or mixture thereof with the proviso that the mixture contains alcohols having the same number of carbon atoms or optionally presenting a different number of carbon atoms. For example, a mixture of butanol comprises two or more of the following alcohols: 1 -butanol, 2-butanol, isobutanol (2 methyl propanol). A mixture of pentanol comprises two or more of the following alcohols: pentan-1 -ol, 3-methylbutan-1 -ol, 2-methylbutan-1 -ol, 2,2- dimethylpropan-1 -ol, pentan-3-ol, pentan-2-ol, 3-methylbutan-2-ol, 2-methylbutan-2-ol. A mixture of hexanol comprises two or more of the following alcohols: 1 -hexanol, 2-hexanol, 3-hexanol, 2- methylpentan-1 -ol, 3-methylpentan-1 -ol, 4-methylpentan-1 -ol, 2-methylpentan-2-ol, 3-methylpentan-2-ol, 4-methylpentan-2-ol, 2-methylpentan-3-ol, 3-methylpentan-3-ol, 2,2-dimethylbutan-1 -ol, 2,3- dimethylbutan-1 -ol, 3,3-dimethylbutan-1 -ol, 2,3-dimethylbutan-2-ol, 3,3-dimethylbutan-2-ol or 2- ethylbutan-1 -ol. More preferably, the alcohol may be selected from C2-C4 alkyl substituted by one hydroxyl group or mixture thereof with the proviso that the alcohols contained in the mixture have the same number of carbon atoms. Advantageously, the invention is of interest for ethanol, 1 -propanol, isopropanol, 1 -butanol, 2-butanol, isobutanol (2 methyl propanol) or mixture thereof with the proviso that the mixture contains alcohols having the same number of carbon atoms. In particular, a mixture of butanol is used, preferably isobutanol (2 methyl propanol) is used.

The inert component is any component provided that there is no adverse effect on the catalyst composition, preferably on the modified crystalline aluminosilicate, in particular on the modified crystalline ferrierite. Because the dehydration is endothermic the inert component can be used to bring energy. By way of examples the inert component is selected among water, saturated hydrocarbons having up to 10 carbon atoms, naphtenes, nitrogen and C0₂. An example of inert component can be any individual saturated compound, a synthetic mixture of the 20 individual saturated compounds as well as some equilibrated refinery streams like straight naphtha, butanes. Advantageously it is a saturated hydrocarbon or a mixture of saturated hydrocarbons having from 3 to 7 carbon atoms, more advantageously having from 4 to 6 carbon atoms and is preferably pentane. The weight proportions of respectively alcohols, water and inert component are, for example, 5-100/0-95/0-95 (the total being 100). Although the reactant could comprise less than about 5% water by weight relative to the weight of the water plus alcohol, it is preferred that the reactant comprise at least about 5% water. In a more specific embodiment, the reactant comprises from about 5% to about 80% water by weight relative to the weight of the water plus alcohol. The dehydration reactor can be a fixed bed reactor (radial, isothermal, adiabatic etc), a moving bed reactor or a fluidized bed reactor. A typical fluid bed reactor is one of the FCC type used for fluidized-bed catalytic cracking in the oil refinery. A typical moving bed reactor is of the continuous catalytic reforming type. The dehydration may be performed continuously in a fixed bed reactor configuration using several reactors in series of equal or different sizes or a pair of parallel "swing" reactors. The various preferred catalysts of the present invention have been found to exhibit high stability. This enables the dehydration process to be performed continuously in two parallel "swing" reactors: while one reactor is operating, the other reactor is undergoing catalyst regeneration. The catalyst of the present invention also can be regenerated several times.

The pressure of the dehydration reactor in the reactor for step (C) or for step b) of the second aspect of the invention can be any pressure but it is more economical to operate at moderate pressure. By way of example the pressure of the reactor may range from 0.5 to 30 bars absolute (50kPa to 3 MPa), advantageously from 0.5 to 10 bars absolute (50kPa to 1 MPa), advantageously from 0.5 to 9 bars absolute (50kPa to 0.9 MPa). Advantageously, the partial pressure of the alcohol is advantageously lower than 5 bars absolute (0.5 MPa) and more advantageously from 0.5 to 4 bars absolute (0.05 MPa to 0.4 MPa), preferably lower than 3.5 bars absolute (0.35 MPa) and more preferably lower than 2 bars absolute (0.2 MPa).

The temperature of the dehydration reactor may range advantageously from 200°C to 500°C, more advantageously from 220°C to 500°C and preferably from 230°C to 450°C. These reaction temperatures refer substantially to average catalyst bed temperature. Dehydration is an endothermic reaction and requires the input of reaction heat in order to maintain catalyst activity sufficiently high and shift the thermodynamic equilibrium to sufficiently high conversion levels. In case of fluidized bed reactors: (i) for stationary fluidized beds without catalyst circulation, the reaction temperature is substantially homogeneous throughout the catalyst bed; (ii) in case of circulating fluidized beds where catalyst circulates between a converting reaction section and a catalyst regeneration section, depending on the degree of catalyst back-mixing the temperature in the catalyst bed approaches homogeneous conditions (a lot of back-mixing) or approaches plug flow conditions (nearly no back-mixing) and hence a decreasing temperature profile will install as the conversion proceeds. In case of fixed bed or moving bed reactors, a decreasing temperature profile will install as the conversion of the alcohol proceeds. In order to compensate for temperature drop and consequently decreasing catalyst activity or approach to thermodynamic equilibrium, reaction heat can be introduced by using several catalyst beds in series with inter-heating of the reactor effluent from the first bed to higher temperatures and introducing the heated effluent in a second catalyst bed, etc. When fixed bed reactors are used, a multi-tubular reactor can be used where the catalyst is loaded in small-diameter tubes that are installed in a reactor shell. At the shell side, a heating medium is introduced that provides the required reaction heat by heat-transfer through the wall of the reactor tubes to the catalyst.

The dehydration reaction of step b) of the second aspect of the invention or steps (B) and/or (C) may be carried out with an alcohol weight hour space velocity ranging from 0.1 h-1 to 20 h-1 , preferably from 0.5 h-1 to 10 h-1 , more preferably from 1 h-1 to 9 h-1 .

The stream (S2) of step (D), comprises essentially water, olefin, the inert component (if any) and unconverted alcohol. Said unconverted alcohol is supposed to be as less as possible. The olefin is recovered by usual fractionation means. Advantageously the inert component, if any, is recycled in the stream (S1 ) as well as the unconverted alcohol, if any.

In a preferred embodiment, said process for the production of olefins from alcohols may further comprises the step of recovering and regenerating the catalyst composition obtained at the end of step (D).

In a preferred embodiment, at least 80% of the olefins recovered in step (D) have the same number of carbon atoms as the alcohol provided in step (A), preferably at least 85%, more preferably at least 90%, in particular at least 95%.

In a preferred embodiment, the present process is carried out with a mixture of butanol as alcohol, preferably isobutanol (2 methyl propanol), and the mixture of olefins produced comprises at least 80% of butene and isomers thereof, preferably at least 90%, more preferably at least 95%, most preferably at least 98%. In addition, the selectivity in n-butenes may be at least 65% based on the total amount of butene and isomers thereof contained in the mixture of olefins produced, preferably at least 70%.

In another preferred embodiment, the process according to the present invention is carried out with ethanol as alcohol and ethylene is produced. The reaction yield may be at least 80%, preferably at least 95%.

In another preferred embodiment, the process according to the present invention is carried out with a mixture of propanol as alcohol and propylene is produced. The reaction yield may be at least 80%, preferably at least 90%.

In another preferred embodiment, the process according to the present invention is carried out with a mixture of hexanol, i.e. alcohol having 6 carbon atoms as defined above, and the mixture of olefins produced comprises at least 80% of hexene and isomers thereof.

In another aspect of the present invention, the mixture of olefins produced according to the present process may be used as starting material for subsequent reactions such as the production of propylene via metathesis process, the production of butadiene via dehydrogenation, oligomerization, as well as for the production of transportation fuels, monomers and fuel additives. The mixture of olefins produced according to the present process may also replace the use of raffinate I in the refinery or petrochembal plants. The most typical application of a mixture containing isobutene is the conversion of the said isobutene into ethers (MTBE and ETBE), into t-butylalcohol (TBA) or oligomers (e.g. di tri-iso- butenes), all being gasoline components. The higher oligomers of isobutene can be used for jet fuel applications. High purity isobutene can further be made by the decomposition of ethers (backcracking) or TBA (dehydration). High purity isobutene finds applications in the production of butyl-rubber, poly-isobutene, methylmethacrylate, isoprene, hydrocarbons resins, t-butyl-amine, alkyl-phenols and t-butyl-mercaptan. When the mixture of olefins contains n-butenes which have not reacted during the production of ethers or TBA and substantially not or only to a limited extend during the oligomerisation, said n-butenes have applications in the production of sec-butanol, alkylate (addition of isobutane to butenes), polygasoline, oxo-alcohols and propylene (metathesis with ethylene or self-metathesis between but-1 -ene and but-2- ene). By means of super fractionation or extractive distillation or absorptive separation but-1 -ene can be isolated from the n-butenes mixture. But-1-ene is used as comonomer for the production of polyethylenes, for polybut-1 -ene and n-butyl-mercaptan. n-Butenes can also be separated from isobutene by means of a catalytic distillation. This involves an isomerisation catalyst that is located in the distillation column and continuously converts the but-1 -ene into but-2-ene, being a heavier component than but-1 - ene. Doing so, a bottom product rich in but-2-ene and a top product poor in but-1 -ene and rich in isobutene is produced. The bottom product can be used as described above. One main application of such but-2-ene rich stream is the metathesis with ethylene in order to produce propylene. If high purity iso-butene is desired the top product can be further super fractionated into substantially pure iso-butene and pure but-1 -ene or the isobutene can be isolated via formation of ethers or TBA that is subsequently decomposed into pure iso-butene. The n-butenes rich stream may be used for the production of butadiene via dehydrogenation or oxidative dehydrogenation or send to alkylation unit to produce bio- alkylate. The mixture of isobutene and butenes can be sent to a catalytic cracking which is selective towards light olefins in the effluent, the process comprising contacting said isobutene and butenes mixture with an appropriate catalyst to produce an effluent with an olefin content of lower molecular weight than that of the feedstock. Said cracking catalyst can be a silicalite (MFI or MEL type) or a P- ZSM5.

In another aspect of the present invention, the catalyst composition according to the present invention, and preferably prepared according to the present invention, is suitable for the production of a mixture of olefins having at least two carbon atoms from alcohols having at least two carbon atoms. Preferably, at least 80% of the olefins produced have the same number of carbon atoms as the alcohol. Preferably, the alcohol is isobutanol and the olefins comprise at least 95% of butene and isomers thereof.

Examples

Starting materials FER1 : NaKFER, with Si/AI of 9.2, supplied by Tosoh Corporation under product reference HSZ-720 KOA has been used as starting material.

FER2: H-FER prepared by ion exchange of FER 1 in 1 .0 mol/L NH₄N0₃ solution for 6 h at room temperature, dried in a static oven under air at 1 10°C, then calcined in air flow (100 mL/min) in a tubular furnace at 550°C for 8 h

FER3: H-FER with Si/AI of 28, supplied by Zeolyst under the commercial name CP914.

The commercial FER of Zeolyst sold under the commercial name CP914C was also analyzed.

The XRD spectrum of FER1 is shown in Figure 1A which shows the high cristallinity of the sample.

Nitrogen sorption measurements performed on FER2 (Figure 1 B) reveal a type I isotherm with a high adsorption in micropores at low relative (p/p°) pressures. At relative pressures higher than 0.9 barg, the adsorbed amount increases due to the condensation of nitrogen between the particles (interparticle mesopores). The sorption measurements are therefore characteristic of a microporous material which does not contain intracrystalline mesopores. TEM images of the crystals in the (010) and (100) directions and micro-diffractograms (Figure 1 C) confirm that the material is highly crystalline and free of intracrystalline mesopores. The composition and textural features of FER1 , FER 2 and FER3 are given in Table 1 .

The XRD, sorption isotherms and TEM images of FER1 samples are given in Figures 1 (A, B, C).

Abbreviations used in the examples, Micro = Micropores; Inter. Meso = Intercrystalline Mesopores, i.e. mesopores located between zeolite crystals ; Intra. Meso = Intracrystalline Mesopores, i.e. mesopores located within a zeolite crystal.

Table 1 : Composition and textural features of FER1 , FER2 and FER3

Sample Yield/% Si/AI Na/AI K/AI (Na+K)/AI

FER1 \ 9.2 0.22 0.70 0.92

Pore volume (cm3/g) Pore size ratio

BET surface area

Sample

(m2/g) Inter. Intra.

Total Micro

Meso Meso

FER2 399 0.18 0.15 0.03 0

FER3 337 0.21 0.13 0.07 0

CP914C 376 0.21 0.14 0.07 0 It is clear from those characterizations that FER1 , FER2, FER3 and CP914C do not present any significant mesoporosity but only some mbroporosity.

Example 1: Mesoporization of FER using Na₂C0₃ solution

In a typical synthesis, 1 .67 g of commercial NaKFER (FER1 , Si/AI = 9.2) was first mixed with 50 imL of 1 .25 mol/L Na₂C0₃ solution (solid/solution=0.0334 g/mL), and then stirred for 30 min. The suspension was hydrothermally treated at 130°C in a Teflon-lined stainless autoclave for 3 days. After cooling the autoclave to room temperature, the solid was filtered under vacuum and washed with de-ionized water repeatedly until pH=7. Finally the product was dried overnight at 80°C to get DeFERI -1.25-130/3. Product yields were calculated as ratio of the amount of recovered solid to the amount of parent solid engaged in the reaction. (In the denomination DeFERI -x-y/z, x is the Na₂C0₃ concentration (mol/L), y is the reaction temperature (°C) and z is the reaction period (days)).

The as-synthesized DeFERI -1 .25-130/3 sample was ion-exchanged in 1.0 mol/L NH₄N0₃ solution for 6 h at room temperature, dried in a static oven under air at 110°C , then calcined in air flow (100 imL/min) in a tubular furnace at 550°C for 8 h, to obtain a sample denoted H-DeFER1 -1 .25-130/3 was obtained.

Table 2: Composition and textural features of the material prepared in example 1

*: dimensionless number XRD diffractogram of H-DeFER1 -1.25-130/3 (Figure 2A) shows that crystallinity of the parent material has been preserved. Nitrogen isotherm (Figure 2B, sample H-DeFER1-1.25-130/3) shows the appearance of a hysteresis loop with an abrupt closing branch around p/p° of 0.42 that is characteristic of a cavitation phenomenon associated with the presence of mesopores connected to the exterior of the crystal by restrictions smaller than ca. 3-4 nm. Compared to the parent material, the micropore volume has been barely modified and 0.03 mL/g of intracrystalline mesopores have been generated. TEM of the crystals in the (010) and (100) directions (Figure 2C) shows that intracrystalline mesopores have been created throughout the whole crystal. The mesopores appear as clear zones in the micrographs. Seen in the (010) direction, they appear as quasi-circular with diameters in the range 20-70 nm. Examination of the crystals in the (100) direction shows that the mesopores consist of elongated voids of 2 to 5 nm in width, running parallel to the 10 MR channel of the microcrystalline structure. In a 3D representation, the mesopores created by the treatment in the Na₂C0₃ solution are described as flat elongated boxes, with a high aspect ratio ( diameter to length, 10-30) oriented in the direction of the main channel of the ferrierite structure and connected to each other via the 10 MR of the framework.

Example 2: Mesopohzation of FER using Na₂CO₃.10H₂O in the absence of added solvent, in the presence of a templating agent (CTAB) A series of samples denoted as DeFER-xCTAB were synthesized where x represents the mass ratio of CTAB (Cetyl Trimethyl Ammonium Bromide) to parent NaKFER using the following recipe:

0.42 grams of NaKFER (FER1 , Si/AI=9.2) were mixed with 4.47 grams of Na₂CO₃- 10H₂O (solid/solid=0.094g/g) and (0.418*x) grams of CTAB (CTAB/NaKFER = x). Then the homogeneous solid mixture was transferred into Teflon-lined stainless autoclave and heated at 130°C for 72 h. After cooling the autoclave to room temperature quickly, the solid was filtered under vacuum and washed with deionized water repeatedly until pH=7.

The recovered product was dried overnight at 80°C to obtain the sample DeFER-xCTAB. Then the sample has been ion-exchanged in 1 .0 mol/L NH₄N0₃ solution for 6 h at room temperature and dried overnight at 80°C. The NH₄-form sample (NH₄-DeFER-xCTAB) was then calcined in air flow (100 mL/min) in a tubular furnace at 550°C for 8 h to get the H-DeFER-xCTAB sample.

Table 3 : Composition and textural features of the materials H-DeFER-xCTAB prepared in example 2.

BET

CTAB/ Pore volume (cm3/g)

Yield Si/AI surface

Samples Zeolite

(%wt) ratio area/m2/ Inter. Intra.

mass ratio Total Micro Meso/Micro g Meso Meso

HFER \ \ 9.2 372 0.17 0.13 0.04 0 0.31

DeFER-

76 0 6.0 462 0.26 0.13 0.05 0.08 1 0CTAB

DeFER-

91 0.25 7.5 449 0.33 0.10 0.10 0.13 2.3 0.25CTAB

DeFER-

94 0.50 7.1 432 0.31 0.1 1 0.10 0.10 1 .8 0.50CTAB

DeFER-

95 1 .0 7.1 430 0.28 0.1 1 0.07 0.10 1 .5 1 .0CTAB Figure 3A shows that, after the treatment, the cristallinity of the mesoporized FER is preserved, even if the peak intensity and cristallinity of the treated samples decrease as the CTAB/FER ratio increases from 0 to 0.5.

The weak diffraction peaks in the small-angle XRD patterns prove the existence of ordered mesostructures.

Figure 3B (N2-sorption isotherm curves at 77K for parent and treated zeolites) shows the presence of mesopores.

TEM of the crystals (Figures 3C and 3D) show that intracrystalline mesopores have been created throughout the crystal. The mesopores appear as clear electron-light zones in the micrographs. Seen in the (010) direction, they appear as quasi-circular mesopores (with round corners and with sides quasi- parallel to the planes of the crystalline structure) with diameters in the range of 20-70 nm. In a 3D representation, the mesopores created by Na₂C0₃ in the solvent-free treatment can be described as occluded mesopores connected to the micropores and oriented in the direction of the micropores. Example 3 Dehydration and skeletal isomehzation of isobutanol using FER2 zeolite

0.5g of catalyst FER2 is sieved to 35-45 mesh, loaded in a quartz reactor and activated in situ for 1 h at 500°C (2°C/min) in flow of He (50 ml/min).

Isobutanol of 99% purity from Sigma-Aldrich has been used (0,806 g/ml density @15°C; 0.085 wt% H₂0; 8 ppm S).

The test has been performed as follows: saturator with isobutanol was heated to 75°C. The lines from the saturator to the entrance of the gas chromatograph (GC) were heated to 150-160°C. Under atmospheric pressure, a flow of 50 ml/min of He was passed through the saturator and resulted in a WHSV of 0.527 mmol/min (around 4.7 g/h) isobutanol. Reaction temperature was raised from 100 to 560°C, using a heating rate of 2°C/min.

Analysis of the products was performed by using an on-line gas chromatography.

Table 4 hereunder shows results obtained with catalyst FER2

T, °c Conversion (i-butanol) Selectivity (2-butenes) Selectivity (butenes) 2-butenes / butenes

mol% mol% mol% mol/mol

159 52,7 36,8 57,0 0,65

211 100 64,2 94,8 0,68

263 99,3 37,4 67,3 0,56

312 98,7 14,6 36,5 0,40

361 99,1 1 1 ,9 29,2 0,41

411 99,6 12,7 30,5 0,42

461 99,8 13,9 32,9 0,42

511 100 22,7 53,4 0,43

561 100 37,1 95,8 0,39 Example 4 Dehydration and skeletal isomerization of isobutanol using H-DeFER1 -1 .25-130/3 zeolite

0.5g of catalyst H-DeFER1 -1 .25-130/3 obtained according to Example 1 is sieved to 35-45 mesh, loaded in a quartz reactor and activated in situ for 1 h at 500°C (2°C/min) in flow of He (50 ml/min).

Isobutanol of 99% purity from Sigma-Aldrich has been used (0,806 g/ml density @15°C; 0,085 wt% H₂0; 8 ppm S).

The test has been performed as follows: saturator with isobutanol was heated to 75°C. The lines from the saturator to the entrance of the GC were heated to 150-160°C. Under atmospheric pressure, a flow of 50 ml/min of He was passed through the saturator and resulted in a WHSV of 0.527 mmol/min (around 4.7 g/h) isobutanol. Reaction temperature was varied between 100 and 560°C, using a heating or cooling rate of 2°C/min .

Analysis of the products was performed by using an on-line gas chromatography.

Table 5 hereunder shows results obtained with catalyst H-DeFER1 -1 .25-130/3.

mol% mol% mol% mol/mol

159 74 37 62 0,59

186 100 62 95 0,65

212 100 63 95 0,66

237 100 59 93 0,63

263 100 47 86 0,54

288 100 34 77 0,44

212 100 65 95 0,68

2-butenes means E- and Z- isomers of but-2-ene.

Butenes means any chemically acceptable isomer of a skeletal structure having 4 carbon atoms and one pi bonding together with one sigma bonding between two carbon atoms, also known as "double bonding": Examples of butenes include but-1 -ene, Z-but-2-ene, E-but-2-ene, 2-methyl-prop-1 -ene, cyclobutene, 1 - methylcycloprop-1 -ene, 1 -methylcycloprop-2-ene.

Isobutanol means 2-methyl-propan-1 -ol .

The comparison of the results of table 4 and table 5 clearly show that the mesoporized FER according to the invention exhibits better performances than the corresponding non mesoporized zeolite:

H-DeFER1 -1 .25-130/3 is more active than the parent FER: at 159°C, isobutanol conversion is 74%mol using H-DeFER1 -1 .25-130/3, whereas isobutanol conversion using FER2 parent zeolite is 53%mol.

At complete conversion, selectivity towards butenes and linear butenes is higher for H-FER1 - 1 .25-130/3 than for the parent zeolite FER2. Example 5 (comparative example) 0.5g of catalyst FER3 is sieved to 35-45 mesh, loaded in a quartz reactor and activated in situ for 1 h at 500°C (2°C/min) in flow of He (50 ml/min).

The test has been performed as follows: saturator with isobutanol was heated to 75°C. The lines between the saturator and the entrance to the GC were heated to 150-160°C. Under atmospheric pressure, a flow of 50 ml/min of He passed through the saturator and resulted in a WHSV of 0.527 mmol/min (around 4.7 g/h) isobutanol. Reaction temperature was changed between 100 and 560°C, using a heating rate of 2°C/min.

Analysis of the products is performed by using an on-line gas chromatography.

Table 6 hereunder shows results obtained with catalyst FER3.

T, Conversion (i- Selectivity (2- Selectivity 2-butenes /

°c butanol) butenes) (butenes) butenes

mol% mol% mol% mol/mol

157 46 13 20 0.65

183 85 55 80 0.68

208 100 70 99 0.71

233 100 68 98 0.69

259 100 57 94 0.61

284 100 45 89 0.50

207 100 74 98 0.75

Claims

CLAIMS:

1 . A method for the transformation of an alcohol into an olefin which comprises contacting said alcohol with a solid catalyst which comprises a zeolitic material of the FER type framework possessing a network of micropores which contains mesopores that are connected to the micropores, wherein the zeolitic material has a ratio of the volume of the mesopores contained within the network of micropores to the volume of the micropores in the range 0.1 to 2.5 preferably 0.1 to 2.

A method according to claim 1 , wherein the zeolitic material of the FER type framework possesses an ordered two-dimensional (2D) network of micropores (ie pores < 2nm in diameter) containing mesopores (pores with diameter in the range 2-50nm) connected to the micropores, the mesopores having an aspect ratio (length to width) higher than 2 and an orientation of the mesopores in the direction of the micropores.

3. A method according to claim 1 or 2, wherein the FER type framework is selected among ferrierite,

FU-9 and ZSM-35.

4. A method according to one any of the preceding claims, wherein the zeolitic material possesses a Si/AI ratio higher than 5 and lower than 10, preferably between 6 and 9.

5. A method according to one any of the preceding claims, wherein the alcohol is contacted with the solid catalyst at a temperature comprised between 100 and 560°C, preferably between 250 and 400°C, with a WHSV of at least 1 h^~1, preferably comprised between 1 and 30h^"1, preferably between 2 and 21 h^" and a pressure comprised between 1 and 20barg, preferably between 1 and 10 barg.

6. A method according to one any of the preceding claims, wherein the alcohol is selected among C2, C3, C4, C5, C6 and C7 alcohols and their mixtures.

7. A method according to claim 6, wherein the alcohol is selected among ethanol, propan-1 -ol, propan-2-ol, 2-methyl-propan-1 -ol, butan-2-ol, 2-methyl-propan-2-ol, butane-1 -ol and their mixtures, eventually in the presence of water wherein preferably said alcohol is 2-methyl-propan- 1 -ol and said olefin is preferably linear butene.

8. A method according to one any of the preceding claims, wherein the alcohol starting material and the olefin product carry the same number of carbon atoms in their backbone.

9. The use of a method according to one any of claims 1 -8 for the preparation of a linear olefin starting from a branched alcohol.

10. Process for the simultaneous dehydration and skeletal isomerisation of a branched alcohol to make the corresponding olefins, having the same number of carbons and consisting of a mixture of n-olefins and branched olefins, said process comprising:

a) introducing in a reactor a stream (A) comprising the branched alcohol, optionally water, optionally an inert component,

b) contacting said stream with a catalyst in said reactor at conditions effective to at least dehydrate and skeletally isomerize at least a portion of the branched alcohol to produce branched olefins and preferably n-olefins,

c) recovering from said reactor a stream (B), comprising removing water, the inert component if any and unconverted branched alcohol if any to get a mixture of branched olefins and preferably n-olefins,

wherein the WHSV of the branched alcohol is at least 1 h^" and the catalyst is capable to make simultaneously the dehydration and skeletal isomerization of olefins and wherein the catalyst contains a mesoporous crystalline silicate of the FER type framework,

1 1 . Process according to claim 10, wherein the zeolitic material of the FER type framework possesses a network of mbropores (ie pores < 2nm in diameter) containing mesopores (pores with diameter in the range 2-50nm) connected to the micropores, and a ratio of the volume of the intracrystalline mesopores to the volume of the micropores in the range 0.1 to 2.

12. Process according to claim 9, 10 or 1 1 , wherein skeletal isomerization is performed simultaneously to the dehydration and results in an increase of the amount of linear olefins and a decrease of the amount of branched olefins.

13. Process according to claims 10 to 12, wherein the preparation of said catalyst comprises the following steps:

(a) contacting a crystalline aluminosilicate of the Framework Type FER with a first metal ion carbonate, preferably chosen among Na2C03, NaHC03 or K2C03 and preferably with a mesopore structure directing agent being preferably cetyl trimethyl ammonium bromide (CTAB), to obtain a first composition, and

(b) heating said first composition in a vessel at a temperature sufficient to increase the pressure above the atmospheric pressure in said vessel or at a pressure of at least 2 bara and at a temperature of at least 80°C, wherein the total amount of water of said first composition originating from the crystalline aluminosilicate of the Framework Type FER and from the first metal ion carbonate is greater or equal to 4 mol per mol of metal ion carbonate, and wherein the first composition obtained at step (a) is not a suspension in water and is under solid state at standard temperature and pressure (STP) before the performance of step (b).

14. Process according to claims 10 to 12, wherein the preparation of said catalyst comprises the following steps:

(a) contacting parent crystalline aluminosilicate of the Framework Type FER with a basic aqueous solution containing at least one weak base i.e. a base having a pKa of at least 7 preferably at least 9, preferably an alkaline metal carbonate, more preferably chosen among Na2C03, NaHC03 or K2C03, at a concentration ranging from 1 M to 2M, preferably between 1 .25M to 2M, to obtain a first composition,

(c) filtering off the zeolite obtained at step (b)

(d) washing it with a solvent, especially a polar solvent, for example pure distilled water, to obtain a washed zeolite,

15. Process according to claims 10 to 12, wherein the preparation of said catalyst comprises the following steps:

(a) contacting a parent crystalline aluminosilicate of the Framework Type FER with a basic aqueous solution containing at least a strong base i.e. a base that is totally dissociated in water such as an alkaline hydroxide base, being preferably NaOH or KOH, at a concentration ranging from 0.2M to 0.3M, more preferably at 0.25M, to obtain a first composition,

(c) filtering off the zeolite obtained at step (b)

(d) washing it with a solvent, especially a polar solvent, for example pure distilled water, to obtain a washed zeolite, wherein optionally the ratio of said parent zeolitic material to said basic aqueous solution in said first composition ranges from 0.02 to 0.05 g/mL, preferably 0.03 to 0.04 g/mL and is most preferably of 0.0334 g/mL