CN110038575B

CN110038575B - Method for preparing specific selective hydrogenation catalysts by kneading and impregnation

Info

Publication number: CN110038575B
Application number: CN201910035628.8A
Authority: CN
Inventors: M.布阿莱; A-C.迪布勒伊
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 2018-01-15
Filing date: 2019-01-15
Publication date: 2023-10-10
Anticipated expiration: 2039-01-15
Also published as: FR3076746A1; CN110038575A; FR3076746B1

Abstract

The present invention discloses a process for preparing a catalyst comprising an oxide matrix and an active phase comprising nickel, said process comprising the steps of: -preparing calcined porous alumina; kneading the obtained calcined porous alumina with at least one solution comprising at least one nickel precursor to obtain a paste at the desired nickel concentration in order to obtain a nickel content of 10% to 35% by weight relative to the total weight of the catalyst, with respect to the dried or calcined catalyst; -shaping the paste obtained; -drying the obtained shaped paste at a temperature lower than 250 ℃ to obtain a dried catalyst precursor; -impregnating the obtained dried catalyst precursor with at least one solution comprising at least one nickel precursor to obtain an impregnated catalyst precursor; drying the impregnated catalyst precursor obtained at a temperature lower than 250 ℃ to obtain a dried catalyst.

Description

Method for preparing specific selective hydrogenation catalysts by kneading and impregnation

Technical Field

The subject of the present invention is a specific process for preparing a catalyst for the selective hydrogenation of polyunsaturated compounds in hydrocarbon feedstocks, in particular C2-C5 steam-cracked fractions and steam-cracked gasolines, or of at least one aromatic or polyaromatic compound present in hydrocarbon feedstocks, which catalyst can effect the conversion of aromatic compounds of petroleum or petrochemical fractions by converting aromatic nuclei into naphthene nuclei.

Background

The most active catalysts in hydrogenation reactions are generally based on noble metals, such as palladium or platinum. These catalysts are used industrially in refining and petrochemistry to purify certain petroleum fractions by hydrogenation, in particular for the selective hydrogenation of polyunsaturated molecules (such as diolefins, acetylenes or alkenyl aromatics) or for the hydrogenation of aromatics. It is generally recommended to replace palladium with nickel, a metal that is less active than palladium. It must therefore be present in the catalyst in greater amounts. Thus, nickel-based catalysts typically have a nickel metal content of 5 wt.% to 60 wt.%, relative to the total weight of the catalyst.

The rate of the hydrogenation reaction depends on several criteria, such as the diffusion of the reactants at the catalyst surface (external diffusion limitation), the diffusion of the reactants to the active sites in the support pores (internal diffusion limitation) and the inherent properties of the active phase, such as the size of the metal particles and the distribution of the active phase within the support.

Regarding internal diffusion limitation, it is important that the pore distribution of macropores and mesopores is adapted to the desired reaction in order to diffuse the reactants in the support pores towards the active sites and to diffuse the formed product towards the outside.

Regarding the size of the metal particles, it is generally considered that the catalyst becomes more active as the size of the metal particles decreases. Furthermore, it is important to obtain a distribution of particle sizes centered around the optimal value and a narrow distribution around the value.

The generally high level of nickel in the hydrogenation catalyst requires a specific synthetic route.

The most common route to preparing these catalysts is to impregnate the support with an aqueous solution of the nickel precursor, typically followed by drying and calcination. These catalysts are typically reduced to obtain an active phase, which is in metallic form (i.e., in the zero-valent state), before they are used in hydrogenation reactions. Catalysts based on nickel supported on alumina prepared by only one impregnation step can generally achieve a nickel content of about 12% to 15% by weight of nickel relative to the total weight of the catalyst, depending on the pore volume of the alumina used. If it is desired to prepare a catalyst having a higher nickel content, several successive impregnations are generally required to obtain the desired nickel content, followed by at least one drying step and then optionally a calcination step between each impregnation.

Thus, document WO2011/080515 describes catalysts based on nickel supported on activated alumina in hydrogenation, in particular of aromatic compounds, having a nickel content of greater than 35% by weight with respect to the total weight of the catalyst and a high degree of dispersion of metallic nickel on the surface of alumina, which has a very open porosity and a high specific surface area. The catalyst is prepared by at least four successive impregnations. Thus, preparing nickel catalysts with high nickel content by the impregnation route implies a series of numerous steps, which increases the corresponding manufacturing costs.

Another preparation route which is also used to obtain catalysts with high nickel content is coprecipitation. Coprecipitation typically involves simultaneous precipitation of an aluminum salt (e.g., aluminum nitrate) and a nickel salt (e.g., nickel nitrate) in a batch reactor. Both salts are precipitated simultaneously. High temperature calcination is then required to convert the alumina gel (e.g., boehmite) to alumina. Nickel contents of up to 70 wt% are achieved by this production route. Catalysts prepared by co-precipitation are described, for example, in documents US 4 273 680, US 8 518 851 and US 2010/016717.

Finally, the preparation route by co-kneading is also known. Co-kneading typically involves mixing a nickel salt with an alumina gel (e.g., boehmite), followed by shaping the resulting mixture, typically by extrusion, followed by drying and calcination. Document US 5 478 791 describes a catalyst based on nickel supported on alumina, having a nickel content of 10% to 60% by weight and a nickel particle size of 15-60nm, prepared by co-kneading a nickel compound with an alumina gel, followed by shaping, drying and reduction.

Furthermore, in order to obtain better catalytic performance qualities, in particular better selectivity and/or activity, it is known in the prior art to use additives of the organic type in the preparation of metal selective hydrogenation catalysts or metal catalysts for hydrogenating aromatic compounds.

For example, application FR 2 984 761 discloses a process for preparing a selective hydrogenation catalyst comprising a support and an active phase comprising a metal from group VIII, said catalyst being prepared by a process comprising a step of impregnation with a solution comprising a precursor of a metal from group VIII and an organic additive, more particularly an organic compound having 1-3 carboxylic acid functions, a step of drying the impregnated support and a step of calcining the dried support to obtain the catalyst.

Document US2006/0149097 discloses a process for hydrogenating aromatic compounds of the benzene polycarboxylic acid type in the presence of a catalyst comprising an active phase containing at least one metal from group VIII, the catalyst being prepared by a process comprising a step of impregnation with a solution containing a precursor of a metal from group VIII and a step of impregnation with an organic additive of the amine or amino acid type. The step of impregnation with the organic additive may be carried out before or after the step of impregnation with the active phase, or even simultaneously.

The inventors have unexpectedly found that a catalyst comprising a nickel-based active phase supported on an alumina-based oxide matrix, prepared by a preparation process comprising the step of co-kneading calcined porous alumina with a solution comprising at least one nickel precursor and comprising the step of impregnating the catalyst precursor comprising the co-kneaded active phase with a solution comprising at least one nickel precursor, can obtain as good performance qualities as known methods of the prior art, even better in terms of activity, in the course of selectively hydrogenating polyunsaturated compounds or hydrogenating aromatic compounds.

The pore distribution obtained by such a preparation method by co-kneading and impregnation may provide a porosity particularly suitable for promoting the diffusion of the reactants in the porous medium and then promoting the reaction of the reactants with the active phase. This is because, in addition to the reduced number of steps and thus the reduced manufacturing costs, the co-kneading and impregnation have the advantage of significantly reducing any risk of partial blockage of the support pores during the deposition of the active phase, thus resulting in a significant reduction in the occurrence of internal diffusion limitations. In addition, such catalysts have distinguishing features that enable the inclusion of a large number of active phases accessible to the reactants. This is because the preparation of the catalyst according to the invention by co-kneading and impregnation enables the catalyst to be loaded with a large amount of active phase.

It is important to emphasize that the catalysts obtained by the preparation process according to the invention are structurally different from catalysts obtained by simple impregnation or by co-kneading of the active phase with the support. Without wishing to be bound by any one theory, it appears that the preparation process according to the invention makes it possible to obtain a composite in which a portion of the nickel particles and a portion of the support are intimately mixed, thus forming the actual structure of the catalyst, with a porosity and active phase content suitable for the desired reaction.

Disclosure of Invention

The first subject of the invention is a process for preparing a catalyst comprising an oxide matrix having a calcined alumina content of greater than or equal to 90% by weight relative to the total weight of the matrix and an active phase comprising nickel, the active phase being free of metals from group VIb and having a nickel content of from 15% to 65% by weight relative to the total weight of the catalyst, the active phase being provided in the form of nickel particles having a diameter of less than or equal to 18nm, the catalyst having a total pore volume of from 0.01 to 1.00ml/g as measured by mercury porosimetry, a mesopore volume of greater than 0.01ml/g as measured by mercury porosimetry, a macropore volume of less than or equal to 0.6ml/g as measured by mercury porosimetry, a median volume median mesopore diameter of from 3 to 25nm, a median volume diameter of from 50 to 1000nm and a macropore volume median diameter of from 25 to 350m ² SBET specific surface area per gram, the method comprising the steps of:

a) Preparing calcined porous alumina;

b) Kneading the calcined porous alumina obtained in step a) with at least one solution comprising at least one nickel precursor to obtain a paste at the desired nickel concentration so as to obtain a nickel content of 10% to 35% by weight relative to the total weight of the catalyst, with respect to the dried or calcined catalyst;

c) Shaping the paste obtained in step b);

d) Drying the shaped paste obtained in step c) at a temperature lower than 250 ℃ to obtain a dried catalyst precursor;

e) Optionally, subjecting the dried catalyst obtained in step d) to a heat treatment at a temperature of 250-1000 ℃ in the presence or absence of water to obtain a calcined catalyst precursor;

f) Impregnating the dried catalyst precursor obtained in step d) or the calcined catalyst precursor obtained in step e) with at least one solution containing at least one nickel precursor to obtain an impregnated catalyst precursor;

g) Drying the impregnated catalyst precursor obtained in step f) at a temperature below 250 ℃ to obtain a dried catalyst.

In a specific embodiment, the dried catalyst obtained in step g) is additionally subjected to a heat treatment step h) at a temperature of 250-1000 ℃ in the presence or absence of water to obtain a calcined catalyst.

Advantageously, the molar ratio of the elemental nickel introduced in the impregnation step f) to the elemental nickel introduced in the co-kneading step b) is between 0.1 and 10mol/mol.

In a first alternative embodiment according to the invention, said calcined porous alumina according to step a) is obtained by:

a1 A first precipitation step of precipitating in an aqueous reaction medium at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid, wherein at least one of the basic precursors or acidic precursors comprises aluminum, the relative flow rates of the acidic precursor and basic precursor being selected to obtain a reaction medium pH of 8.5-10.5, and the flow rates of the one or more acidic precursors and basic precursor of aluminum being adjusted to obtain a rate of progress of the first step of 5% -13%, the rate of progress being defined as the rate of progress of Al during the first precipitation step ₂ O ₃ The ratio of the alumina formed by the equivalent to the total amount of alumina formed at the end of step a 3) of the preparation process, said step being carried out at a temperature of 20-90 ℃ for 2 to 30 minutes;

a2 A step of heating the suspension at a temperature of 40-90 ℃ for 7 minutes to 45 minutes;

a3 A second precipitation step of precipitating the suspension obtained at the end of the heating step a 2) by adding to the suspension at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid, wherein at least one of the basic precursors or the acidic precursors comprises aluminum, the relative flow rates of the acidic precursor and the basic precursor being selected to obtain a reaction medium pH of 8.5 to 10.5, and the flow rates of the one or more acidic precursors and the basic precursor of aluminum being adjusted so as to obtain a progress rate of the second step of 87% -95%, the progress rate being defined as Al during the second precipitation step ₂ O ₃ The ratio of the alumina formed by the equivalent to the total amount of alumina formed at the end of step a 3) of the preparation process, said step being carried out at a temperature of 40-90 ℃ for 2 to 50 minutes;

a4 A step of filtering the suspension obtained at the end of the second precipitation step a 3) to obtain an alumina gel;

a5 A step of drying the alumina gel obtained in step a 4) to obtain a powder;

a6 A step of heat-treating the powder obtained at the end of step a 5) at 500-1000 ℃ in the presence or absence of an air stream containing up to 60% by volume of water for 2-10 hours to obtain calcined porous alumina.

In a second alternative embodiment according to the invention, said calcined porous alumina according to step a) is obtained by:

a 1') a step of dissolving an acidic aluminum precursor selected from aluminum sulfate, aluminum chloride and aluminum nitrate in water at a temperature of 20 to 90 ℃ and a pH of 0.5 to 5 for a period of 2 to 60 minutes,

a2 ') a step of adjusting the pH by adding at least one alkaline precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide to the suspension obtained in step a 1') at a temperature of 20 to 90℃and a pH of 7 to 10 for a period of 5 to 30 minutes,

a3 ') a step of coprecipitating the suspension obtained at the end of step a 2') by adding to the suspension at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid, at least one of the basic precursors or acidic precursors comprising aluminum, the relative flow rates of the acidic precursor and basic precursor being selected to obtain a reaction medium pH of 7-10, and the flow rates of the one or more acidic precursors and basic precursors containing aluminum being adjusted to obtain a final alumina concentration in the suspension of 10-38g/l,

a4 ') a step of filtering the suspension obtained at the end of the coprecipitation step a 3') to obtain an alumina gel,

a5 ') a step of drying the alumina gel obtained in step a 4') to obtain a powder,

a6 ') a step of heat-treating the powder obtained at the end of step a 5') at a temperature of 500-1000 ℃ for 2-10 hours in the presence or absence of an air stream containing up to 60% by volume of water to obtain calcined porous alumina.

In a third alternative embodiment according to the invention, said calcined porous alumina according to step a) is obtained by:

a1 ") at least one first precipitation step of precipitating alumina from at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid in an aqueous reaction medium, wherein at least one of the basic precursors or acidic precursors comprises aluminum, the relative flow rates of the acidic precursor and basic precursor being selected to obtain a reaction medium pH of 8.5-10.5, and the flow rates of one or more acidic precursors of aluminum and basic precursor being adjusted so as to obtain a rate of progress of the first step of 40% -100%, the rate of progress being defined as Al during the first precipitation step ₂ O ₃ The ratio of the alumina formed by the equivalent relative to the total amount of alumina formed at the end of step c) of the preparation process, saidThe first precipitation step is carried out at a temperature of 10-50 ℃ for 2 minutes to 30 minutes;

a2 ") a heat treatment step of heating the suspension at a temperature of 50-200 ℃ for 30 minutes to 5 hours to obtain an alumina gel;

a3″ a step of filtering the suspension obtained at the end of the heat treatment step a2 '') followed by at least one step of washing the gel obtained;

a4″ a step of drying the alumina gel obtained at the end of step a3 ") to obtain a powder;

a5 '') a step of heat-treating the powder obtained at the end of step a4 '') at a temperature of 500-1000 ℃ in the presence or absence of an air stream containing up to 60% by volume of water to obtain calcined porous alumina.

In one embodiment according to the invention, in step b), the porous alumina is additionally kneaded with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amine function, or at least one amide function.

In one embodiment according to the invention, in step f), the dried catalyst precursor obtained in step d) or the calcined catalyst precursor obtained in step e) is additionally impregnated with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amine function, or at least one amide function.

Preferably, said step f) comprises the sub-steps of:

f1 Impregnating the catalyst precursor obtained in step d) or step e) with at least one solution containing at least one nickel precursor;

f2 Impregnating the catalyst precursor obtained in step d) or step e) with at least one solution containing at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function;

it will be appreciated that sub-step f 1) and sub-step f 2) may be performed separately, in any order, or simultaneously.

Advantageously, the organic compound comprises at least one carboxylic acid functional group selected from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids or tetracarboxylic acids.

In a preferred embodiment, the organic compound comprising at least one alcohol function is selected from:

-an organic compound comprising only one alcohol function;

-an organic compound comprising two alcohol functions;

selected from diethylene glycol, triethylene glycol, tetraethylene glycol or corresponding to formula H (OC ₂ H ₄ ) _n An OH, an organic compound of polyethylene glycol wherein n is greater than 4 and has an average molar mass of less than 20 000 g/mol;

Having an empirical formula C _n (H ₂ O) _p Wherein n is 3-12;

derivatives of disaccharides, trisaccharides or monosaccharides.

In a preferred embodiment, the organic compound comprising at least one ester functional group is selected from:

-a linear carboxylic acid ester or a cyclic carboxylic acid ester or an unsaturated cyclic carboxylic acid ester;

-an organic compound comprising at least two carboxylate functional groups;

-an organic compound comprising at least one carboxylate functionality and at least one second functionality selected from alcohols, ethers, ketones or aldehydes;

-cyclic or linear carbonates;

-a linear carbonic acid diester.

In a preferred embodiment, the organic compound comprising at least one amide function is selected from:

acyclic amides comprising one or two amide functions;

-cyclic amides or lactams;

-an organic compound comprising at least one amide function and a carboxylic acid function or an alcohol function;

-an organic compound comprising at least one amide function and a further nitrogen heteroatom.

In a preferred embodiment, the organic compound comprises at least one amine functional group corresponding to the empirical formula C _x N _y H _z Where x is 1 to 20, y=1 to x and z=2 to (2x+2).

Advantageously, the molar ratio of said organic compound introduced in step b) and/or in step f) to the elemental nickel introduced in step b) is between 0.01 and 5.0mol/mol.

The second subject matter according to the invention relates to a process for the selective hydrogenation of polyunsaturated compounds containing at least 2 carbon atoms per molecule, such as diolefins and/or acetylenes and/or alkenyl aromatics, present in a hydrocarbon feedstock having a final boiling point of less than or equal to 300 ℃, said process being carried out in the liquid phase at a temperature of from 0 to 300 ℃, a pressure of from 0.1 to 10MPa, a hydrogen/(polyunsaturated compound to be hydrogenated) molar ratio of from 0.1 to 10 and a reaction time of from 0.1 to 200h ^-1 Is carried out at a hourly space velocity or, when the process is carried out in the gas phase, at a molar ratio of hydrogen/(polyunsaturated compounds to be hydrogenated) of from 0.5 to 1000 and from 100 to 40,000 hours ^-1 Is carried out at a hourly space velocity in the presence of the catalyst obtained by the preparation process according to the invention.

The third subject matter according to the invention relates to a process for hydrogenating at least one aromatic or polyaromatic compound present in a hydrocarbon feedstock having a final boiling point of less than or equal to 650 ℃, in the gas phase or liquid phase, at a temperature of from 30 to 350 ℃, a pressure of from 0.1 to 20MPa, a molar ratio of hydrogen/(aromatic compound to be hydrogenated) of from 0.1 to 10 and from 0.05 to 50h ^-1 Is carried out in the presence of a catalyst obtained by the preparation process according to the invention.

Detailed Description

Definition of the definition

"macropores" is understood to mean pores with openings greater than 50 nm.

"mesoporous" is understood to mean pores with openings ranging from 2nm to 50nm, inclusive.

"microporous" is understood to mean pores with openings of less than 2 nm.

The total pore volume of the catalyst or of the support used to prepare the catalyst according to the invention is understood to mean the volume measured by mercury porosimetry using a mercury porosimeter at a maximum pressure of 4000 bar (400 MPa) using a surface tension of 484 dynes/cm and a contact angle of 140 ° according to standard ASTM D4284-83. According to the recommendation of the works "Techniques de l' ing nieur, trait analyse et caract e base" [ Techniques of the Engineer, analysis Treatise and Characterization ], pages 1050-1055, written by Jean Charpin and Bernard Ras Neur, a wetting angle equal to 140℃is adopted.

To obtain better accuracy, the value of the total pore volume corresponds to the value of the total pore volume measured by mercury porosimetry on the sample minus the value of the total pore volume measured by mercury porosimetry on the same sample for a pressure of 30psi (about 0.2 MPa).

Macropore and mesopore volumes were measured by mercury porosimetry according to standard ASTM D4284-83 using a surface tension of 484 dyne/cm and a contact angle of 140℃at a maximum pressure of 4000 bar (400 MPa). The value of mercury filling all inter-particulate voids was set to 0.2MPa, and it is considered that if it is greater than this value, mercury permeates into the pores of the sample.

The macropore volume of the catalyst or of the support used to prepare the catalyst according to the invention is defined as the cumulative volume of mercury introduced at a pressure of 0.2MPa to 30MPa, corresponding to the volume present in pores with apparent diameter greater than 50 nm.

The mesopore volume of the catalyst or of the support used for the preparation of the catalyst according to the invention is defined as the cumulative volume of mercury introduced at a pressure of 30MPa to 400MPa, corresponding to the volume present in pores with apparent diameters of 2 to 50 nm.

The volume of the microwells was measured by nitrogen porosimetry. Quantitative analysis of microporosity was carried out starting from the "t" method (Lippens-De Boer method, 1965) which corresponds to the transformation of the initial adsorption isotherm, as described in the works "Adsorption by powders and porous matrices, principles, methodology and applications" (Academic Press, 1999) written by f.

In addition, the median mesopore diameter is defined as the diameter such that all of the combined pores constituting the mesopore volume have a size smaller than that of 50% of the total mesopore volume as measured by mercury porosimetry using a mercury porosimeter.

In addition, the median macropore diameter is defined as the diameter such that all of the pores having a size smaller than the diameter in the combined pores constituting the macropore volume account for 50% of the total macropore volume as determined by mercury porosimetry using a mercury porosimeter.

The specific surface area of the catalyst or of the support used for preparing the catalyst according to the invention is understood to mean the BET specific surface area determined by nitrogen adsorption according to the standard ASTM D3663-78 formulated by the Brunauer-Emmett-Teller method described in journal "The Journal of the American Chemical Society",60, 309 (1938).

The size of the nickel nanoparticles is understood to mean the average diameter of the nickel crystallites measured in their oxide form. The average diameter of nickel crystallites in oxide form was determined by X-ray diffraction from the width of the diffraction line lying at angle 2θ=43° (that is to say in crystallographic direction [200 ]) using the Scherrer relation. This method is used in X-ray diffraction on polycrystalline samples or powders, which relates the full width at half maximum of the diffraction peak to the size of the particle, and is described in detail in the following references: appl. Cryst (1978), 11, 102-113, "Scherrer after sixty years: A survey and some new results in the determination of crystallite size", j.i. Langford and a.j.c. Wilson.

Subsequently, the family of chemical elements is given according to CAS taxonomies (CRC Handbook of Chemistry and Physics, CRC Press publication, master code D.R.Lide, 81 th edition, 2000-2001). For example, group VIII according to CAS classification corresponds to the metals according to the new IUPAC classification, columns 8, 9 and 10.

Description of the method for preparing the catalyst

Generally, the method of preparing a catalyst comprises the steps of:

a) Preparing calcined porous alumina (also referred to herein indiscriminately as an "oxide matrix" or "support");

c) Shaping the paste obtained in step b);

g) Drying the impregnated catalyst precursor obtained in step f) at a temperature below 250 ℃ to obtain a dried catalyst;

h) Optionally, the dried catalyst obtained in step g) is subjected to a heat treatment at a temperature of 250-1000 ℃ in the presence or absence of water to obtain a calcined catalyst.

Advantageously, the calcined porous alumina is obtained from a specific alumina gel. The particular pore distribution observed in the catalyst is due in particular to the preparation process starting from a particular alumina gel.

Step a): preparation of calcined alumina

Calcined alumina can be synthesized by different methods known to those skilled in the art. For example, a method of obtaining a gel composed of a gamma-aluminum hydroxide oxide (AlO (OH)) type precursor (also referred to as boehmite) is employed. For example, the alumina gel may be obtained by precipitation of an alkaline and/or acidic solution of an aluminum salt caused by a change in pH or any other method known to those skilled in the art. The process is described in particular by the literature Alumia in "Handbook of Porous Solids" edited by F.Schuth, K.S.W. Sing and J.Weitkamp (Wiley-VCH, weinheim, germany, 2002, pages 1591-1677) by P.Euzen, P.Raybaud, X.Krokidis, H.Toulhoat, J.L.LeLoarer, J.P.Jolivet and C.Froidefond.

Particularly preferably, the porous alumina is prepared from a specific alumina gel prepared according to a specific preparation method as described below.

Embodiment 1:

according to a first alternative form, the calcined porous alumina used in the process for preparing the catalyst according to the invention is obtained by carrying out the following steps:

a5 A step of drying the alumina gel obtained in step a 4) to obtain a powder; for example at a temperature of 20-200 ℃ for 8-15 hours;

The rate of progress of each precipitation step is defined as Al during the first precipitation step or the second precipitation step ₂ O ₃ Equivalent-formed alumina is used as Al at the end of the two precipitation steps, more generally at the end of the step of preparing the alumina gel, in particular at the end of step a 3) of the preparation method according to the invention ₂ O ₃ The ratio of the total amount of alumina formed by the equivalents.

Embodiment 2:

according to a second alternative form, the calcined porous alumina used in the process for preparing the catalyst according to the invention is obtained by carrying out the following steps:

a5 ') a step of drying the alumina gel obtained in step a 4') to obtain a powder, said drying step being carried out at a temperature of 120-300 ℃ and very preferably at a temperature of 150-250 ℃ for 2-16 hours,

Embodiment 3:

according to a third alternative form, the calcined porous alumina used in the process for preparing the catalyst according to the invention is obtained by carrying out the following steps:

a1 ") at least one first precipitation step of precipitating alumina from at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid in an aqueous reaction medium, wherein at least one of the basic precursors or acidic precursors comprises aluminum, the relative flow rates of the acidic precursor and basic precursor being selected to obtain a reaction medium pH of 8.5-10.5, and the flow rates of one or more acidic precursors of aluminum and basic precursor being adjusted so as to obtain a rate of progress of the first step of 40% -100%, the rate of progress being defined as Al during the first precipitation step ₂ O ₃ The ratio of the alumina formed by the equivalent to the total amount of alumina formed at the end of step c) of the preparation process, the first precipitation step being carried out at a temperature of 10-50 ℃ for 2 to 30 minutes;

a4″ a step of drying the alumina gel obtained at the end of step a3 ") to obtain a powder; the drying step is carried out at a temperature of 20-250 ℃, preferably 50-200 ℃, for 1 day to 3 weeks, preferably 2 hours to 1 week, more preferably 5 hours to 48 hours;

a5 ") a step of heat-treating the powder obtained at the end of step a 4") at a temperature of 500-1000 ℃ in the presence or absence of an air stream containing up to 60% by volume of water for 2 to 10 hours to obtain calcined porous alumina.

In general, the "rate of progress" of the nth precipitation step is understood to mean that in said nth step Al is present ₂ O ₃ The percentage of alumina formed by the equivalent relative to the total amount of alumina formed at the end of all precipitation steps, more typically at the end of the step of preparing the alumina gel.

Wherein said sinkAt a progression rate of 100% of the precipitation step a 1'), said precipitation step a1 ") generally makes it possible to obtain Al ₂ O ₃ Alumina suspension at a concentration of 20-100g/g, preferably 20-80g/l, preferably 20-50 g/l.

Step b): co-kneading

In this step, the calcined porous alumina obtained in step a) is kneaded with at least one solution comprising at least one nickel precursor.

The one or more solutions comprising at least one nickel precursor may be aqueous or comprise an organic solvent or comprise a mixture of water and at least one organic solvent (e.g., ethanol or toluene). Preferably, the solution is aqueous. The pH of the solution may be changed by optionally adding an acid. According to another preferred alternative, the aqueous solution may contain ammonia or ammonium ions NH ⁴⁺ 。

Preferably, the nickel precursor is introduced in the form of an aqueous solution, for example in the form of a nitrate, carbonate, acetate, chloride, hydroxide, hydroxycarbonate or oxalate, in the form of a complex formed from a polyacid or an acid alcohol and salts thereof, in the form of a complex with an acetylacetonate or any other inorganic derivative soluble in an aqueous solution, and is brought into contact with the calcined porous alumina. Preferably, nickel nitrate, nickel chloride, nickel acetate or basic nickel carbonate is advantageously used as nickel precursor. Very preferably, the nickel precursor is nickel nitrate or basic nickel carbonate.

According to another preferred alternative, the nickel precursor is introduced into the ammonia-containing solution by introducing a nickel salt (e.g. nickel hydroxide or nickel carbonate) into the ammonia solution or ammonium carbonate solution or ammonium bicarbonate solution.

According to the application, the solution comprising at least one nickel precursor is provided in the desired concentration in order to obtain a nickel content of 10% to 35% by weight, preferably 12% to 30% by weight, more preferably 14% to 28% by weight, relative to the total weight of the catalyst, with respect to the dried catalyst (obtained in step f) if no calcination step is carried out) or the calcined catalyst (obtained in step g) if a calcination step is carried out on the dried catalyst). This is because the inventors company has unexpectedly found that a specific contribution of nickel of 10% to 35% by weight, preferably of 12% to 30% by weight, more preferably of 14% to 28% by weight, relative to the total weight of the catalyst, in the co-kneading step a) makes it possible to obtain a final catalyst exhibiting improved performance qualities in terms of activity in the selective hydrogenation of polyunsaturated compounds or in the hydrogenation of aromatic compounds.

In a specific embodiment according to the application, the step of co-kneading with a solution resulting from the mixing of one or more solutions comprising nickel precursors and at least one solution comprising at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function is carried out in step b).

This is because it has additionally been noted that catalysts according to the invention prepared in the presence of organic compounds (as described above) are more active than catalysts according to the prior art prepared in the absence of such organic compounds. This effect is associated with a reduction in nickel particle size.

Advantageously, the molar ratio of the organic compound introduced in step b) to the elemental nickel also introduced in step b) is from 0.01 to 5.0mol/mol, preferably from 0.05 to 2.0mol/mol, more preferably from 0.1 to 1.5mol/mol, still more preferably from 0.3 to 1.2 mol/mol.

The one or more solutions comprising at least one organic compound comprising at least one carboxylic acid functionality, or at least one alcohol functionality, or at least one ester functionality, or at least one amide functionality, or at least one amine functionality may be aqueous, or organic (e.g., methanol or ethanol or phenol or acetone or toluene or dimethyl sulfone (DMSO)), or comprise a mixture of water and at least one organic solvent. The one or more organic compounds are at least partially dissolved in the one or more solutions in advance at a desired concentration. Preferably, the one or more solutions are aqueous or contain ethanol. More preferably, the solution is aqueous. The pH of the solution may be changed by optionally adding an acid or a base.

The co-kneading is advantageously carried out in a kneader, for example of the "Brabender" type, known to the person skilled in the art. Placing the calcined alumina powder obtained in step a) into a vessel of a kneader. Subsequently, at a given kneading rate, over a period of time (typically about 2 minutes), using a syringe or any other means, a solution obtained by mixing one or more solutions comprising at least one nickel precursor or a solution obtained by mixing one or more solutions comprising at least one nickel precursor and at least one solution comprising at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function, and optionally deionized water is added. After the paste is obtained, kneading may be continued at 50 rpm for several minutes, for example, about 15 minutes.

The solution resulting from the mixing operation may also be added in several portions during this co-kneading step.

A) Organic compound comprising at least one carboxylic acid function

In one embodiment according to the invention, the organic compound comprises at least one carboxylic acid functional group.

The organic compound comprising at least one carboxylic acid functional group may be a saturated or unsaturated aliphatic or aromatic organic compound. Preferably, the saturated or unsaturated aliphatic organic compound contains from 1 to 9 carbon atoms, preferably from 2 to 7 carbon atoms. Preferably, the aromatic organic compound comprises 7 to 10 carbon atoms, preferably 7 to 9 carbon atoms.

The saturated or unsaturated aliphatic organic compound comprising at least one carboxylic acid functional group or the aromatic organic compound may be selected from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids or tetracarboxylic acids.

In a specific embodiment of the invention, the organic compound is a saturated aliphatic monocarboxylic acid, the aliphatic chain of which is straight or branched or cyclic. When the organic compound is a saturated linear monocarboxylic acid, it is preferably selected from formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid or nonanoic acid. When the organic compound is a saturated branched monocarboxylic acid, it is preferably selected from isobutyric acid, pivalic acid, 4-methyl octanoic acid, 3-methyl pentanoic acid, 4-methyl pentanoic acid, 2-methyl pentanoic acid, isovaleric acid, 2-ethyl hexanoic acid, 2-methyl butyric acid, 2-ethyl butyric acid, 2-propyl pentanoic acid or valproic acid, in any of its isomeric forms. When the organic compound is a saturated cyclic monocarboxylic acid, it is preferably selected from cyclopentanecarboxylic acid or cyclohexanecarboxylic acid.

In a specific embodiment of the invention, the organic compound is an unsaturated aliphatic monocarboxylic acid, the aliphatic chain of which is linear or branched or cyclic, preferably selected from methacrylic acid, acrylic acid, vinylacetic acid, crotonic acid, isocrotonic acid, penten-2-oic acid, penten-3-oic acid, penten-4-oic acid, tiglic acid, angelic acid, sorbic acid or propiolic acid, in any of its isomeric forms.

In a specific embodiment of the present invention, the organic compound is an aromatic monocarboxylic acid, preferably selected from benzoic acid, methylbenzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, ethylbenzoic acid, o-tolylacetic acid, phenylacetic acid, 2-phenylpropionic acid, 3-phenylpropionic acid, 4-vinylbenzoic acid, phenylpropionic acid or cinnamic acid, in any of its isomeric forms.

In a specific embodiment of the invention, the organic compound is a saturated or unsaturated aliphatic dicarboxylic acid, the aliphatic chain of which is straight or branched or cyclic. When the organic compound is a saturated, linear dicarboxylic acid, it is preferably selected from oxalic acid (oxalic acid), malonic acid (propanedioic acid), succinic acid (succinic acid), glutaric acid (glutamic acid), adipic acid (fatty acid), pimelic acid (syzygotic acid), suberic acid (cork acid) or azelaic acid (azelaic acid). When the organic compound is a saturated branched dicarboxylic acid, it is preferably selected from 2-methylpentanedioic acid, 3-dimethylpentanedioic acid, 2-dimethylpentanedioic acid or butane-1, 2-dicarboxylic acid, in any of its isomeric forms.

When the organic compound is a saturated cyclic dicarboxylic acid, it is preferably selected from cyclohexane dicarboxylic acid or pinonic acid, in either of its isomeric forms.

Preferably, the organic compound is selected from oxalic acid (oxalic acid), malonic acid, succinic acid (succinic acid), glutaric acid (glutamic acid), 1, 2-cyclohexanedicarboxylic acid or 1, 3-cyclohexanedicarboxylic acid, in any of its isomeric forms. More preferably, the organic compound is selected from oxalic acid (oxalic acid), malonic acid, succinic acid (succinic acid) or glutaric acid (glutamic acid).

When the organic compound is an unsaturated linear or branched or cyclic dicarboxylic acid, it is preferably selected from (Z) -butenedioic acid (maleic acid), (E) -butenedioic acid (fumaric acid), pent-2-enedioic acid (pentendioic acid), (2E, 4E) -hex-2, 4-dienedioic acid (muconic acid), mesaconic acid, citraconic acid, butynedioic acid, 2-methylenesuccinic acid (itaconic acid) or hex-2, 4-dienedioic acid, in any of its isomeric forms.

Preferably, the organic compound is selected from (Z) -butenedioic acid (maleic acid), (E) -butenedioic acid (fumaric acid), pent-2-enedioic acid (glutaconic acid), mesaconic acid, citraconic acid or 2-methylenesuccinic acid (itaconic acid), in any of its isomeric forms. Still more preferably, the organic compound is selected from (Z) -butenedioic acid (maleic acid), (E) -butenedioic acid (fumaric acid) or pent-2-enedioic acid (glutaconic acid).

In a specific embodiment of the invention, the organic compound is an aromatic dicarboxylic acid, preferably selected from benzene-1, 2-dicarboxylic acid (phthalic acid), benzene-1, 3-dicarboxylic acid (isophthalic acid), benzene-1, 4-dicarboxylic acid (terephthalic acid) or phenylsuccinic acid, in any of its isomeric forms. Preferably, the organic compound is benzene-1, 2-dicarboxylic acid (phthalic acid).

In a specific embodiment of the invention, the organic compound is a saturated or unsaturated aliphatic or aromatic tricarboxylic acid, preferably selected from 1,2, 3-propanetricarboxylic acid (trimesic acid), 1,2, 4-butanetricarboxylic acid, 1,2, 3-propenetriac acid (aconitic acid), 1,3, 5-benzenetricarboxylic acid (trimesic acid) or 1,2, 4-benzenetricarboxylic acid, in any of its isomeric forms. Preferably, the organic compound is selected from 1,2, 3-propane tricarboxylic acid (trimesic acid), 1,2, 4-butane tricarboxylic acid, 1,2, 3-propylene tricarboxylic acid (aconitic acid) or 1,2, 4-benzene tricarboxylic acid, in any of its isomeric forms.

In a specific embodiment of the invention, the organic compound is a saturated or unsaturated aliphatic or aromatic tetracarboxylic acid, preferably selected from methane tetracarboxylic acid, 1,2,3, 4-butane tetracarboxylic acid, ethylene tetracarboxylic acid or 1,2,4, 5-benzene tetracarboxylic acid, in any of its isomeric forms. Preferably, the organic compound is selected from 1,2,3, 4-butanetetracarboxylic acid or 1,2,4, 5-benzenetetracarboxylic acid, in any of its isomeric forms.

In another embodiment according to the invention, the organic compound may comprise at least one second functional group selected from ethers, hydroxy, ketones or esters. Advantageously, the organic compound comprises at least one carboxylic acid function and at least one hydroxyl function, or comprises at least one carboxylic acid function and at least one ether function, or comprises at least one carboxylic acid function and at least one ketone function. Advantageously, the organic compound may comprise at least three different functional groups selected from at least one carboxylic acid functional group, at least one hydroxyl functional group and at least one functional group other than carboxylic acid functional groups and hydroxyl functional groups (for example ether functional groups or ketone functional groups).

Among the organic compounds comprising at least one carboxylic acid function and at least one hydroxyl function, mention may be made of hydroxy acids of monocarboxylic, dicarboxylic or polycarboxylic acids, dihydroxy acids of monocarboxylic or polycarboxylic acids, and more generally polyhydroxy acids of monocarboxylic or polycarboxylic acids, the carbon chain of which may be a saturated (linear, branched or cyclic) aliphatic chain or an unsaturated (linear, branched or cyclic) aliphatic chain or contain at least one aromatic ring. Preferably, the organic compound is selected from the group consisting of hydroxy acids or dihydroxy acids of monocarboxylic, or dicarboxylic, or tricarboxylic acids.

When the organic compound is a hydroxy acid of a monocarboxylic acid, it is preferably selected from glycolic acid (glycolic acid), 2-hydroxypropionic acid (lactic acid), 2-hydroxyisobutyric acid or other alpha-hydroxy acids, 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxypentanoic acid, 3-hydroxyisobutyric acid, 3-hydroxy-3-methylbutanoic acid or other beta-hydroxy acids, 4-hydroxybutyric acid or other gamma-hydroxy acids, mandelic acid, 3-phenyllactic acid, tropenic acid, hydroxybenzoic acid, salicylic acid, (2-hydroxyphenyl) acetic acid, (3-hydroxyphenyl) acetic acid, (4-hydroxyphenyl) acetic acid or coumaric acid, in any of its isomeric forms. Preferably, the organic compound is selected from glycolic acid (glycolic acid), 2-hydroxypropionic acid (lactic acid), 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxyisobutyric acid, mandelic acid, 3-phenyllactic acid, topiramate or salicylic acid, in any of its isomeric forms. More preferably, the organic compound is selected from glycolic acid (glycolic acid), 2-hydroxypropionic acid (lactic acid), 3-hydroxypropionic acid, 3-hydroxybutyric acid or 3-hydroxyisobutyric acid.

When the organic compound is a hydroxy acid of a polycarboxylic acid, it is preferably selected from 2-hydroxy malonic acid (tartronic acid), 2-hydroxy succinic acid (malic acid), acetolactic acid or other alpha-hydroxy acids of dicarboxylic acids, or beta-hydroxy acids, or gamma-hydroxy acids, 5-hydroxy isophthalic acid, 2-hydroxy propane-1, 2, 3-tricarboxylic acid (citric acid), isocitric acid, homocitric acid, homoisocitric acid or other alpha-hydroxy acids of tricarboxylic acids, or beta-hydroxy acids, or gamma-hydroxy acids, in any of their isomeric forms. Preferably, the organic compound is selected from 2-hydroxy malonic acid (tartronic acid), 2-hydroxy succinic acid (malic acid), acetolactic acid, 2-hydroxy propane-1, 2, 3-tricarboxylic acid (citric acid), isocitric acid, homocitric acid or homoisocitric acid, in any of its isomeric forms. More preferably, the organic compound is selected from 2-hydroxy malonic acid (tartronic acid), 2-hydroxy succinic acid (malic acid), acetolactate or 2-hydroxy propane-1, 2, 3-tricarboxylic acid (citric acid).

When the organic compound is a dihydroxyic acid of a monocarboxylic acid, it is preferably selected from glyceric acid, 2, 3-dihydroxy-3-methylpentanoic acid, pantoic acid or other α, α -dihydroxyic acid, or α, β -dihydroxyic acid, or α, γ -dihydroxyic acid, 3, 5-dihydroxy-3-methylpentanoic acid (mevalonic acid), or other β, β -dihydroxyic acid, or β, γ -dihydroxyic acid, or γ, γ -dihydroxyic acid, bis (hydroxymethyl) -2, 2-propionic acid, 2, 3-dihydroxybenzoic acid, α -resorcinol, β -resorcinol, γ -resorcinol, or caffeic acid, in any of its isomeric forms. Preferably, the organic compound is selected from glyceric acid, 2, 3-dihydroxy-3-methylpentanoic acid, pantoic acid, 2, 3-dihydroxybenzoic acid, β -resorcinol acid, γ -resorcinol acid, gentisic acid or orcinolanoic acid, in any of its isomeric forms. More preferably, the organic compound is selected from glyceric acid, 2, 3-dihydroxy-3-methylpentanoic acid or pantoic acid.

When the organic compound is a dihydroxy acid of a polycarboxylic acid, it is preferably selected from the group consisting of dihydroxymalonic acid, 2, 3-dihydroxysuccinic acid (tartaric acid) or other α, α -dihydroxyacids of dicarboxylic acids, or α, β -dihydroxyacids, or α, γ -dihydroxyacids, or β, β -dihydroxyacids, or γ, γ -dihydroxyacids, or hydroxycitric acid, in any of its isomeric forms. Preferably, the organic compound is selected from the group consisting of dihydroxymalonic acid, 2, 3-dihydroxysuccinic acid (tartaric acid), or hydroxycitric acid, in any of its isomeric forms. More preferably, the organic compound is selected from the group consisting of dihydroxymalonic acid or 2, 3-dihydroxysuccinic acid (tartaric acid).

When the organic compound is a polyhydroxy acid of a mono-or polycarboxylic acid, it is preferably selected from shikimic acid, trihydroxybenzoic acid, gallic acid, phloroglucinol acid, pyrogallol carboxylic acid, quinic acid, gluconic acid, mucic acid or sugar acid, in any of its isomeric forms. Preferably, the organic compound is selected from the group consisting of trihydroxybenzoic acid, quinic acid, gluconic acid, mucic acid or sugar acid, in any of its isomeric forms. More preferably, the organic compound is selected from quinic acid, gluconic acid, mucic acid or sugar acid.

Among the organic compounds comprising at least one carboxylic acid function and at least one ether function, mention may be made of 2-methoxyacetic acid, 2' -oxydiacetic acid (diglycolic acid), 4-methoxybenzoic acid, 4-isopropoxybenzoic acid, 3-methoxyphenylacetic acid, 3-methoxycinnamic acid, 4-methoxycinnamic acid, 3, 4-dimethoxycinnamic acid, veratric acid, tetrahydrofuran-2-carboxylic acid, furan-3-carboxylic acid or 2, 5-dihydrofuran-3, 4-dicarboxylic acid, according to any of its isomeric forms. Preferably, the organic compound is 2,2' -oxydiacetic acid (diglycolic acid).

Among the organic compounds comprising at least one carboxylic acid function and at least one ketone function, mention may be made of glyoxylic acid, 2-oxopropionic acid (pyruvic acid), 2-oxobutyric acid, 3-oxopentanoic acid, 3-methyl-2-oxobutyric acid, 4-methyl-2-oxopentanoic acid, phenylglyoxylic acid, phenylpyruvic acid, mesooxalic acid, 2-oxoglutaric acid, 2-oxoadipic acid, oxalosuccinic acid or other alpha-keto acids of mono-or polycarboxylic acids, acetoacetic acid, acetone dicarboxylic acid or other beta-keto acids of mono-or polycarboxylic acids, 4-oxopentanoic acid (levulinic acid) or other gamma-keto acids of mono-or polycarboxylic acids, 4-acetylbenzoic acid, dioxosuccinic acid, 4-maleoacetoacetic acid or other polycarboxylic acids of mono-or polycarboxylic acids, according to any of their isomeric forms. Preferably, the organic compound is selected from glyoxylic acid, 2-oxopropionic acid (pyruvic acid), 2-oxobutyric acid, 3-methyl-2-oxobutyric acid, phenylglyoxylic acid, phenylpyruvic acid, mesooxalic acid, 2-oxoglutarate, 2-oxoadipic acid, oxalosuccinic acid, acetoacetic acid, acetonedicarboxylic acid, 4-oxopentanoic acid (levulinic acid), or dioxosuccinic acid, according to any of its isomeric forms. Still more preferably, the organic compound is selected from glyoxylic acid, 2-oxopropionic acid (pyruvic acid), 2-oxobutyric acid, 3-methyl-2-oxobutyric acid, mesooxalic acid, 2-oxoglutarate, acetoacetic acid, acetonedioic acid, 4-oxopentanoic acid (levulinic acid), or dioxosuccinic acid.

Among the organic compounds comprising at least one carboxylic acid function and at least one ester function, acetylsalicylic acid may be mentioned.

Among the organic compounds comprising at least one carboxylic acid function, at least one hydroxyl function and at least one ether function, mention may be made of 4-hydroxy-3-methoxybenzoic acid (vanilloid), syringic acid, glucuronic acid, galacturonic acid, ferulic acid or sinapic acid, according to any of its isomeric forms. Preferably, the organic compound is selected from 4-hydroxy-3-methoxybenzoic acid (vanillic acid), glucuronic acid or galacturonic acid, according to any of its isomeric forms.

Among the organic compounds comprising at least one carboxylic acid function, at least one hydroxyl function and at least one ketone function, mention may be made of hydroxypyruvate, acetolactate, iduronic acid, ulonic acid, meconic acid or 4-hydroxyphenylpyruvic acid, according to any of its isomeric forms. Preferably, the organic compound is selected from hydroxypyruvate, acetolactate, iduronic acid or meconic acid, according to any of its isomeric forms.

In all of the foregoing embodiments, the process steps, the organic compound comprising at least one carboxylic acid functional group is preferably selected from oxalic acid (oxalic acid), malonic acid, succinic acid (succinic acid), glutaric acid (glutamic acid), 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, (Z) -butenedioic acid (maleic acid), (E) -butenedioic acid (fumaric acid), pent-2-enedioic acid (glutaconic acid), mesaconic acid, citraconic acid, 2-methylenesuccinic acid (itaconic acid), benzene-1, 2-dicarboxylic acid (phthalic acid), 1,2, 3-propane tricarboxylic acid (trimesic acid), 1,2, 4-butane tricarboxylic acid, 1,2, 3-propene tricarboxylic acid (aconitic acid), 1,2, 4-benzene tricarboxylic acid, 1,2,3, 4-butane tetracarboxylic acid 1,2,4, 5-benzene tetracarboxylic acid, glycolic acid (glycolic acid), 2-hydroxy propionic acid (lactic acid), 3-hydroxy propionic acid, 3-hydroxy butyric acid, 3-hydroxy isobutyric acid, mandelic acid, 3-phenyl lactic acid, tropinic acid, salicylic acid, glyceric acid, 2, 3-dihydroxy-3-methyl valeric acid, pantoic acid, 2, 3-dihydroxybenzoic acid, beta-resorcinol acid, gamma-resorcinol acid, gentisic acid, orcinolanoic acid, dihydroxymalonic acid, 2, 3-dihydroxysuccinic acid (tartaric acid), hydroxycitric acid, trihydroxybenzoic acid, quinic acid, gluconic acid, mucic acid, sugar acid, 2' -oxydiacetic acid (diglycolic acid), glyoxylic acid, 2-oxopropionic acid (pyruvic acid), 2-oxobutyric acid, 3-methyl-2-oxobutyric acid, phenylglyoxylic acid, phenylpyruvic acid, medium oxalic acid, 2-oxoglutaric acid, 2-oxoadipic acid, oxalosuccinic acid, acetoacetic acid, acetone dicarboxylic acid, 4-oxovaleric acid (levulinic acid), dioxosuccinic acid, 4-hydroxy-3-methoxybenzoic acid (vanilloic acid), glucuronic acid, galacturonic acid, hydroxypyruvic acid, acetolactic acid, iduronic acid or itaconic acid, according to any of its isomeric forms.

In all the preceding embodiments, the organic compound comprising at least one carboxylic acid functional group is more preferably selected from oxalic acid (oxalic acid), malonic acid, succinic acid (succinic acid), glutaric acid (glutamic acid), (Z) -butenedioic acid (maleic acid), (E) -butenedioic acid (fumaric acid), pent-2-enedioic acid (pentendioic acid), glycolic acid (glycolic acid), 2-hydroxypropionic acid (lactic acid), 3-hydroxypropionic acid, 3-hydroxybutyric acid, 3-hydroxyisobutyric acid, 2-hydroxymalonic acid (tartronic acid), 2-hydroxysuccinic acid (malic acid), acetolactic acid, 2-hydroxypropane-1, 2, 3-tricarboxylic acid (citric acid), glyceric acid, 2, 3-dihydroxy-3-methylpentanoic acid, pantoic acid, dihydroxymalonic acid, 2, 3-dihydroxysuccinic acid (tartaric acid), quinic acid, gluconic acid, mucic acid, sugar acid, glyoxylic acid, 2-oxopropionic acid (pyruvic acid), 2-oxobutyric acid, 3-methyl-2-oxobutyric acid, mesooxalic acid, 2-oxoglutarate, acetoacetic acid, 4-oxopentanoic acid or succinic acid. Still more preferably, the organic compound comprising at least one carboxylic acid functional group is selected from oxalic acid (oxalic acid), malonic acid, glutaric acid (glutamic acid), glycolic acid (glycolic acid), 2-hydroxypropionic acid (lactic acid), 2-hydroxymalonic acid (tartronic acid), 2-hydroxypropane-1, 2, 3-tricarboxylic acid (citric acid), 2, 3-dihydroxysuccinic acid (tartaric acid), 2-oxopropionic acid (pyruvic acid) or 4-oxopentanoic acid (levulinic acid).

B) Organic compound comprising at least one alcohol function

In another embodiment according to the invention, the organic compound comprises at least one alcohol function.

Preferably, the organic compound comprises 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms.

In one embodiment according to the invention, the organic compound comprises only one alcohol function (monohydric alcohol). Preferably, the organic compound is selected from methanol, ethanol, propanol, butanol, pentanol, hexanol, 2-propyn-1-ol, geraniol, menthol, phenol or cresol, in any of its isomeric forms. More preferably, the organic compound is selected from methanol, ethanol or phenol.

In another embodiment according to the invention, the organic compound comprises at least two alcohol functions (diols or more generally polyols). Preferably, the organic compound is selected from the group consisting of ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 2-propanediol, 1, 2-butanediol, 2, 3-butanediol, 1, 2-pentanediol, 1, 3-pentanediol, 2, 4-pentanediol, 2-ethyl-1, 3-hexanediol (ethylhexanediol), p-menthane-3, 8-diol, 2-methyl-2, 4-pentanediol, but-2-yn-1, 4-diol, 2,3, 4-trihydroxybentane, 2-dihydroxyhexane, 2, 4-trihydroxyhexane, glycerol, erythritol, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, dulcitol, allitol, glucitol, malitol, fucitol, sevofluritol, sevoflurane, and any of the isomeric forms thereof. More preferably, the organic compound is selected from ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, glycerol, xylitol, mannitol or sorbitol, in any of its isomeric forms.

In another embodiment according to the invention, the organic compound is an aromatic organic compound comprising at least two alcohol functional groups. Preferably, the organic compound is selected from catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, pyrogallol, tetrahydroxybenzene or benzene hexaol, in any of its isomeric forms. More preferably, the organic compound is selected from catechol, resorcinol or hydroquinone.

In another embodiment according to the invention, the organic compound may be selected from diethylene glycol, triethylene glycol, tetraethylene glycol or more generally corresponds to formula H (OC ₂ H ₄ ) _n OH, polyethylene glycol wherein n is greater than 4 and has an average molar mass of less than 20 g/mol. More preferably, the organic compound is selected from diethylene glycol, triethylene glycol or polyethylene glycol having an average molar mass of less than 600 g/mol.

In another embodiment according to the invention, the organic compound is of the empirical formula C _n (H ₂ O) _p Wherein n is 3 to 12,preferably 3-10. Preferably, the organic compound is selected from glyceraldehyde, dihydroxyacetone, erythrose, threose, erythrulose, lyxose, arabinose, xylose, ribose, ribulose, xylulose, glucose, mannose, sorbose, galactose, fructose, allose, altrose, gulose, idose, talose, allose, tagatose, sedoheptose or mannoheptulose, in any of its isomeric forms. More preferably, the organic compound is selected from glucose, mannose or fructose, in any of its isomeric forms.

In another embodiment according to the invention, the organic compound is a disaccharide, or a trisaccharide, or a derivative of a monosaccharide selected from sucrose, maltose, lactose, cellobiose, gentiobiose, inulin disaccharide, isomaltose, isomaltulose, trabiose, lactulose, laminabiose, leuconostoc disaccharide, maltose, melibiose, aspergillus niger, locust sugar, rutinose, sophorose, fucosyllactose, gentiobiose, inulotriose, kestose, trehalose, melibiose, glucopyranosyl sucrose, maltotriose, mannotriose, neokestose, panose, raffinose, murine Li San sugar, maltitol, lactitol, isomalt or isomaltulose, in any of its isomeric forms. More preferably, the organic compound is selected from sucrose, maltose or lactose, in any of its isomeric forms.

In another embodiment according to the invention, the organic compound comprises at least one alcohol function, at least one ketone function and at least an unsaturated heterocycle, preferably selected from isomalt, maltol, ethyl maltol, dehydroacetic acid, kojic acid or isoascorbic acid, in any of its isomeric forms.

In all the preceding embodiments, the organic compound comprising at least one alcohol functional group is preferably selected from the group consisting of methanol, ethanol, propanol, butanol, pentanol, hexanol, 2-propyn-1-ol, geraniol, menthol, phenol, cresol, ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 2-propanediol, 1, 2-butanediol, 2, 3-butanediol, 1, 3-butanediolDiols, 1, 2-pentanediol, 1, 3-pentanediol, 2, 4-pentanediol, 2-ethyl-1, 3-hexanediol, p-menthane-3, 8-diol, 2-methyl-2, 4-pentanediol, 2-butine-1, 4-diol, 2,3, 4-trihydroxypentane, 2-dihydroxyhexane, 2, 4-trihydroxyhexane, glycerol, erythritol, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, dulcitol, allitol, glucitol, tolitol, fucitol, iditol, heptatol, inositol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, pyrogallol, tetrahydroxybenzene, benzene hexaol, diethylene glycol, triethylene glycol, tetraethylene glycol, corresponding to formula H (OC) ₂ H ₄ ) _n The presence of OH, wherein n is greater than 4 and has an average molar mass of less than 20 g/mol, polyethylene glycol, glyceraldehyde, dihydroxyacetone, erythrose, threose, erythrulose, lyxose, arabinose, xylose, ribose, ribulose, xylulose, glucose, mannose, sorbose, galactose, fructose, allose, altrose, gulose, idose, talose, allose, tagatose, sedoheptose, mannoheptulose, sucrose, maltose, lactose, cellobiose, gentiobiose, inulin disaccharide, isomaltose, isomaltulose melibiose, lactulose, laminariae disaccharide, leuconostoc disaccharide, maltose, melibiose, aspergillus niger, locust sugar, melibiose, glucopyranosyl sucrose, fucosyl lactose, rutinose, sophorose, trehalose, gentitriose, inulotriose, kestose, maltotriose, mannotriose, melezitose, neokestose, panose, raffinose, murine Li San sugar, maltitol, lactitol, isomalt, isomaltulose, isomalt, maltol, ethyl maltol, dehydroacetic acid, kojic acid or isoascorbic acid, in any of its isomeric forms.

More preferably, the organic compound is selected from methanol, ethanol, phenol, ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, glycerol, xylitol, mannitol, sorbitol, catechol, resorcinol, hydroquinone, diethylene glycol, triethylene glycol, polyethylene glycols having an average molar mass of less than 600g/mol, glucose, mannose, fructose, sucrose, maltose or lactose, in any of its isomeric forms.

C) Organic compound comprising at least one ester function

In another embodiment according to the invention, the organic compound comprises at least one ester functional group.

Preferably, the organic compound comprises 2 to 20 carbon atoms, preferably 3 to 14 carbon atoms, more preferably 3 to 8 carbon atoms.

According to the invention, the organic compound comprises at least one ester function. It may be selected from linear carboxylic acid esters or cyclic carboxylic acid esters or unsaturated cyclic carboxylic acid esters, or cyclic or linear carbonates, or may also be selected from linear carbonic acid diesters.

In the case of cyclic carboxylic acid esters, the compound may be a saturated cyclic ester. The term used is alpha-lactone, beta-lactone, gamma-lactone, delta-lactone or epsilon-lactone, depending on the number of carbon atoms in the heterocycle. The compounds may also be substituted with one or more alkyl or aryl groups or alkyl groups containing unsaturation. Preferably, the compound is a lactone having 4 to 12 carbon atoms, such as gamma-butyrolactone, gamma-valerolactone, delta-valerolactone, gamma-caprolactone, delta-caprolactone, epsilon-caprolactone, gamma-heptanolactone, delta-heptanolactone, gamma-octalactone, delta-nonanolactone, epsilon-nonanolactone, delta-decanolide, gamma-decanolide, epsilon-decanolide, delta-dodecalactone or gamma-dodecalactone, in any of its isomeric forms. Still more preferably, the compound is a gamma-lactone or delta-lactone, gamma-butyrolactone, gamma-valerolactone, delta-valerolactone, gamma-caprolactone, delta-caprolactone, gamma-heptanolide, delta-heptanolide, gamma-octalactone or delta-octalactone having from 4 to 8 carbon atoms, in any of its isomeric forms. Preferably, the compound is gamma valerolactone.

In the case of unsaturated cyclic carboxylic acid esters (containing unsaturation in the ring), the compound may be furanone or pyrone or any of its derivatives, for example 6-pentyl-alpha-pyrone.

In the case of linear carboxylic esters, the compounds may be those corresponding to the empirical formula RCOOR 'containing only one ester function, wherein R and R' are linear, branched or cyclic alkyl groups, or alkyl groups containing unsaturation, or alkyl groups substituted with one or more aromatic rings, or aryl groups, each containing from 1 to 15 carbon atoms and which may be the same or different. The R group may also be a hydrogen atom H. Preferably, the R ' group (of the alkoxy functional group COR ') contains carbon atoms less than or equal to the number of carbon atoms of the R group, even more preferably the number of carbon atoms of the R ' group is from 1 to 6, still more preferably from 1 to 4. The organic compound is preferably selected from methyl formate, methyl acetate, methyl propionate, methyl butyrate, methyl valerate, methyl caproate, methyl caprylate, methyl caprate, methyl laurate, ethyl acetate, ethyl propionate, ethyl butyrate, ethyl valerate or ethyl caproate. Preferably, the organic compound is methyl laurate.

In another embodiment according to the invention, the organic compound may be a compound comprising at least two carboxylate functional groups.

Advantageously, the carbon chain into which these carboxylate functions are inserted is a linear or branched or cyclic aliphatic carbon chain, saturated or containing unsaturation and containing from 2 to 15 carbon atoms, and each R 'group (of each alkoxy function COR') may be a linear, branched or cyclic alkyl group, or an alkyl group containing unsaturation, or an alkyl group substituted by one or more aromatic rings, or an aryl group, and containing from 1 to 15 carbon atoms, preferably from 1 to 6 carbon atoms, still more preferably from 1 to 4 carbon atoms. The different R' groups may be the same or different. Preferably, the compound is selected from dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl oxalate, diethyl malonate, diethyl succinate, diethyl glutarate, diethyl adipate, dimethyl methylsuccinate or dimethyl 3-methylglutarate, in any of its isomeric forms. More preferably, the compound is dimethyl succinate.

In another embodiment according to the invention, the organic compound may be a compound comprising at least one carboxylate functionality and at least one second functionality selected from alcohols, ethers, ketones or aldehydes.

Advantageously, the organic compound comprises at least one carboxylate functional group and at least one alcohol functional group.

Preferably, the carbon chain into which the carboxylate function or functions are inserted is a linear or branched or cyclic aliphatic carbon chain, which is saturated or may contain unsaturation and contains from 2 to 15 carbon atoms, and each R ' group (of each alkoxy function COR ') may be a linear, branched or cyclic alkyl group, or an alkyl group containing unsaturation, or an alkyl group substituted with one or more aromatic rings, or an aryl group, and contains from 1 to 15 carbon atoms, preferably from 1 to 6 carbon atoms, still more preferably from 1 to 4 carbon atoms, and the different R ' groups may be the same or different. Such carbon chains contain at least one hydroxyl group, preferably 1-6 hydroxyl groups.

Preferably, the compound is selected from methyl glycolate, ethyl glycolate, butyl glycolate, benzyl glycolate, methyl lactate, ethyl lactate, butyl lactate, t-butyl lactate, ethyl 3-hydroxybutyrate, ethyl mandelate, dimethyl malate, diethyl malate, diisopropyl malate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, trimethyl citrate, or triethyl citrate, in any of its isomeric forms. More preferably, the compound is dimethyl malate.

Advantageously, the organic compound comprises at least one carboxylate functionality and at least one ketone or aldehyde functionality. Preferably, the carbon chain into which the carboxylate function or functions are inserted is a linear or branched or cyclic aliphatic carbon chain, which is saturated or may contain unsaturation and contains from 2 to 15 carbon atoms, and each R ' group (of each alkoxy function COR ') may be a linear, branched or cyclic alkyl group, or an alkyl group containing unsaturation, or an alkyl group substituted with one or more aromatic rings, or an aryl group, and contains from 1 to 15 carbon atoms, preferably from 1 to 6 carbon atoms, still more preferably from 1 to 4 carbon atoms, and the different R ' groups may be the same or different. Such carbon chains contain at least one ketone or aldehyde functional group, preferably 1-3 ketone or aldehyde functional groups. Preferably, the organic compound is acetoacetic acid (acetoacetic acid).

In the case of cyclic carbonates, the compound may be ethylene carbonate, propylene carbonate or trimethylene carbonate. Preferably, the compound is propylene carbonate.

In the case of linear carbonates, the compound may be dimethyl carbonate, diethyl carbonate or diphenyl carbonate.

In the case of linear carbonic acid diesters, the compound may be dimethyl dicarbonate, diethyl dicarbonate or di (t-butyl) dicarbonate.

Advantageously, the organic compound may comprise at least three different functional groups selected from at least one ester functional group, at least one carboxylic acid functional group and at least one functional group other than ester functional groups and carboxylic acid functional groups (for example ether functional groups or ketone functional groups).

In all of the foregoing embodiments, the process steps, the organic compound comprising at least one ester function is preferably selected from the group consisting of gamma-lactone or delta-lactone containing 4 to 8 carbon atoms, gamma-butyrolactone, gamma-valerolactone, delta-valerolactone, gamma-caprolactone, delta-caprolactone, gamma-heptanolactone, delta-heptanolactone, gamma-octanolactone, delta-octanolactone, methyl formate, methyl acetate, methyl propionate, methyl butyrate, methyl valerate, methyl caproate, methyl caprylate, methyl caprate, methyl laurate, ethyl acetate, ethyl propionate, ethyl butyrate, ethyl valerate, ethyl caproate, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, diethyl oxalate, diethyl malonate diethyl succinate, diethyl glutarate, diethyl adipate, dimethyl methylsuccinate, dimethyl 3-methylglutarate, methyl glycolate, ethyl glycolate, butyl glycolate, benzyl glycolate, methyl lactate, ethyl lactate, butyl lactate, t-butyl lactate, ethyl 3-hydroxybutyrate, ethyl mandelate, dimethyl malate, diethyl malate, diisopropyl malate, dimethyl tartrate, diethyl tartrate, diisopropyl tartrate, trimethyl citrate, triethyl citrate, ethylene carbonate, propylene carbonate, trimethylene carbonate, diethyl carbonate, diphenyl carbonate, dimethyl dicarbonate, diethyl dicarbonate or di (t-butyl) dicarbonate, in any of its isomeric forms.

D) Organic compound comprising at least one amide function

In another embodiment according to the invention, the organic compound comprises at least one amide function selected from acyclic amide functions or cyclic amide functions optionally comprising alkyl substituents, aryl substituents or alkyl substituents containing unsaturation. The amide functionality may be selected from primary, secondary or tertiary amides.

According to a first alternative form, the organic compound comprises at least one acyclic amide functionality.

The organic compound may contain only one amide function and no other functional groups, such as formamide, N-methylformamide, N-dimethylformamide, N-ethylformamide, N-diethylformamide, N-dibutylformamide, N-diisopropylformamide, N, N-diphenylformamide, acetamide, N-methylacetamide, N-dimethylformamide, N-diethylacetamide, N-dimethylpropionamide, propionamide, N-ethyl-N-methylpropionamide, benzamide or acetanilide, according to any of its isomeric forms. Preferably, the organic compound is selected from the group consisting of formamide, N-methylformamide, N-dimethylformamide, N-ethylformamide, N-diethylformamide, acetamide, N-methylacetamide, N-dimethylformamide, N-diethylacetamide, N-dimethylpropionamide or propionamide.

The organic compound may contain two amide functions and be free of other functional groups, such as tetraacetyl ethylenediamine.

According to a second alternative form, the organic compound comprises at least one cyclic amide function, such as a 1-formylpyrrolidine or a 1-formylpiperidine, or a lactam function. Preferably, the organic compound is selected from the group consisting of beta-lactam, gamma-lactam, delta-lactam and epsilon-lactam and derivatives thereof, according to any of its isomeric forms. More preferably, the organic compound is selected from 2-pyrrolidone, N-methyl-2-pyrrolidone, gamma-lactam or caprolactam, according to any one of its isomeric forms.

According to a third alternative, the organic compound may comprise at least one amide function and at least one other function than an amide function. Preferably, the organic compound comprises at least one amide functionality and at least one carboxylic acid functionality, such as acetylleucine, N-acetyl aspartic acid, amino hippuric acid, N-acetyl glutamic acid or 4-acetamidobenzoic acid, according to any of its isomeric forms.

Preferably, the organic compound comprises at least one amide functionality and at least one alcohol functionality, such as hydroxyacetamide, lactamide, N-diethyl-2-hydroxyacetamide, 2-hydroxy-N-methylacetamide, 3-hydroxypropionamide, mandelamide, acetohydroxamic acid, butyryl hydroxamic acid or pudding (busetin), according to any of its isomeric forms. Preferably, the organic compound is selected from the group consisting of lactamide and hydroxyacetamide.

According to a fourth alternative form, the organic compound comprises at least one amide function and at least one further nitrogen heteroatom, preferably selected from urea, N-methyl urea, N' -dimethyl urea, 1-dimethyl urea or tetramethyl urea, according to any of its isomeric forms.

Among all the above-mentioned organic compounds comprising at least one amide function, formamide, N-methylformamide, N-dimethylformamide, N-ethylformamide, N-diethylformamide, acetamide, N-methylacetamide, N-dimethylformamide, N-diethylacetamide, N, N-dimethylpropionamide, propionamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, gamma-lactam, caprolactam, acetylleucine, N-acetylaspartic acid, carbamuric acid, N-acetylglutamic acid, 4-acetamidobenzoic acid, lactamide and hydroxyacetamides, urea, N-methylurea, N' -dimethylurea, 1-dimethylurea or tetramethylurea, according to any of its isomeric forms.

E) Organic compound comprising at least one amine function

In another embodiment according to the invention, the organic compound comprises at least one amine functional group.

The organic compound contains 1 to 20 carbon atoms, preferably 1 to 14 carbon atoms, more preferably 2 to 8 carbon atoms.

In one embodiment according to the invention, the organic compound comprises at least one amine function corresponding to the empirical formula C _x N _y H _z Where x is 1 to 20, y=1 to x and z=2 to (2x+2). The organic compound may be selected from saturated or unsaturated aliphatic, cyclic, alicyclic, aromatic or heterocyclic amines, optionally containing an alkyl substituent, an aryl substituent or an alkyl substituent containing unsaturation. The amine functional group may be selected from primary, secondary or tertiary amines.

According to a first alternative, the organic compound comprises only one amine function and no other functions.

More specifically, the organic compound comprising only one amine function is selected from aliphatic compounds, such as propylamine, ethylmethylamine, butylamine, dimethylisopropylamine, dipropylamine, diisopropylamine or octylamine, from cyclic or alicyclic compounds, such as cyclobutylamine or cyclohexylamine, from aromatic compounds, such as aniline, N-dimethylaniline or dimethylaniline, from saturated heterocyclic compounds, such as piperidine, pyrrolidine or morpholine, or from unsaturated heterocyclic compounds, such as pyrrole, pyridine, indole or quinoline, which compounds may be substituted by one or more alkyl groups, one or more aryl groups or one or more alkyl groups containing unsaturation.

According to a second alternative, the organic compound comprises two amine functions and no other functional groups.

More specifically, the organic compound comprising two amine functions is selected from aliphatic compounds, such as ethylenediamine, 1, 3-diaminopropane, 1, 2-diaminopropane, diaminohexane, tetramethylenediamine, hexamethylenediamine, tetramethylethylenediamine, tetraethylethylenediamine, N '-dibenzylethylenediamine (benzathine), xylylenediamine or diphenylethylenediamine, from cyclic or alicyclic compounds, such as 1, 2-diaminocyclohexane, from aromatic compounds, such as phenylenediamine and its derivatives, 4' -diaminobiphenyl or 1, 8-diaminonaphthalene, or from heterocyclic compounds, such as piperazine, imidazole, pyrimidine or purine, which may be substituted by one or more alkyl groups, one or more aryl groups or one or more alkyl groups containing unsaturation. Preferably, the organic compound is selected from ethylenediamine, diaminohexane, tetramethylenediamine, hexamethylenediamine, tetramethylethylenediamine or tetraethylethylenediamine.

According to a third alternative form, the organic compound comprises at least three amine functions and is free of other functions. More particularly, the compound is selected from diethylenetriamine or triethylenetetramine.

In all cases described above which contain at least one amine function corresponding to the empirical formula C _x N _y H _z Of the organic compounds (wherein 1.ltoreq.x.ltoreq.20, 1.ltoreq.y.ltoreq.x, 2.ltoreq.z.ltoreq.2x+2), ethylenediamine, diaminohexane, tetramethylenediamine, hexamethylenediamine, tetramethylethylenediamine, tetraethylethylenediamine, diethylenetriamine or triethylenetetramine are particularly preferred.

In one embodiment according to the invention, the organic compound comprises at least one amine function and at least one carboxylic acid function (amino acid). In the amino acid, the organic compound may be selected from the following compounds: alanine, arginine, asparagine, pyroglutamic acid, citrulline, gabapentin (gabapentin), glutamine, histidine, isoleucine, isoglutamine, leucine, lysine, norvaline, ornithine, phenylalanine, proline, microzyme amino acid, sarcosine, serine, threonine, tryptophan, tyrosine, valine, pyrrolysine, 2-aminoisobutyric acid or ethylenediamine tetraacetic acid (EDTA), according to any of its isomeric forms. When the compound is an amino acid, it is preferably selected from alanine, arginine, lysine, proline, serine, threonine or EDTA.

Step c): shaping

The paste obtained at the end of the co-kneading step b) is then shaped according to any technique known to the person skilled in the art, for example by means of extrusion, by granulation, by the oil-drop (drying) method or by granulation on a rotating plate.

Preferably, the paste is extruded in the form of an extrudate, the diameter of the extrudate typically being from 0.5 to 10mm, preferably from 0.8 to 3.2mm, very preferably from 1.0 to 2.5mm. This may advantageously be in the form of a cylindrical, trilobal or quadrulobal extrudate. Preferably, the shape is trilobal or quadrilobal.

Very preferably, the co-kneading step b) and the shaping step c) are combined in a single kneading/extrusion step. In this case, the paste obtained at the end of kneading may be introduced into a piston extruder to pass through a die having a desired diameter (usually 0.5 to 10 mm).

Step d): dry formed paste

According to the invention, the shaped paste is dried d) at a temperature of less than 250 ℃, preferably 15-240 ℃, more preferably 30-220 ℃, more preferably 50-200 ℃, even more preferably 70-180 ℃ in a more preferred manner, typically for 10 minutes to 24 hours. Longer times are not precluded but do not necessarily contribute to improvement.

The drying step may be carried out by any technique known to the person skilled in the art. It is advantageously carried out under an inert atmosphere or under an oxygen-containing atmosphere or under a mixture of inert gas and oxygen. It is advantageously carried out at atmospheric or reduced pressure. Preferably, this step is carried out at atmospheric pressure in the presence of air or nitrogen.

Step e): heat treating the dried catalyst (optional)

Subsequently, the dried catalyst precursor obtained in step d) may be subjected to a further heat treatment or hydrothermal treatment step e) at a temperature of 250-1000 ℃, preferably 250-750 ℃, in the presence or absence of water, under an inert atmosphere or under an oxygen-containing atmosphere, which step is typically carried out for 15 minutes to 10 hours. Longer treatment times are not precluded, but do not necessarily contribute to improvement. Several heat treatments or combined cycles of hydrothermal treatments may be performed. After this or these treatments, the catalyst precursor comprises nickel in the oxide form, i.e. in the NiO form.

In the case of water addition, the contact with steam can take place at atmospheric pressure or at autogenous pressure. The water content is preferably 150-900 g per kg of dry air, more preferably 250-650 g per kg of dry air.

Step f): dipping

The impregnation step f) may be carried out by impregnation under dry conditions or in excess according to methods known to the person skilled in the art. The step f) is preferably carried out by impregnating the catalyst precursor obtained at the end of step d) or step e), for example by contacting the catalyst precursor with at least one solution, which is aqueous or organic (for example methanol or ethanol or phenol or acetone or toluene or Dimethylsulfoxide (DMSO)) or a mixture comprising water and at least one organic solvent, which contains at least one nickel precursor in at least partially dissolved state, or by contacting the catalyst precursor with at least one colloidal solution of at least one nickel precursor in oxidized form (nanoparticles of oxides, oxides (hydroxides) or hydroxides of nickel) or in reduced form (metal nanoparticles of nickel in reduced state). Preferably, the solution is aqueous. The pH of the solution may be changed by the optional addition of an acid or base. According to another preferred alternative, the aqueous solution may contain ammonia or ammonium ions NH ⁴⁺ 。

Preferably, said step f) is carried out by impregnation under dry conditions, which comprises contacting said catalyst precursor with at least one solution containing at least one nickel precursor, said solution having a volume which is 0.25-1.5 times the pore volume of the support of the catalyst precursor to be impregnated.

When the nickel precursor is introduced in the form of an aqueous solution, it is advantageously brought into contact with the catalyst precursor in the form of a nickel precursor in the form of a complex with acetylacetonate, or in the form of a nickel precursor in the form of a tetramine or hexamine, or in the form of any other inorganic derivative which is soluble in aqueous solution, using a nickel precursor in the form of a nitrate, carbonate, chloride, sulfate, hydroxide, hydroxycarbonate, formate, acetate or oxalate. Nickel nitrate, nickel carbonate, nickel chloride, nickel hydroxide or basic nickel carbonate is advantageously used as nickel precursor. Very preferably, the nickel precursor is nickel nitrate, nickel carbonate, or nickel hydroxide.

The amount of the one or more nickel precursors introduced into the solution is selected such that the total content of elemental nickel is 15 wt% to 65 wt%, preferably 18 wt% to 55 wt%, more preferably 20 wt% to 50 wt%, more preferably 22 wt% to 45 wt%, even more preferably 25 wt% to 43 wt% of the weight of the dried or calcined catalyst.

Advantageously, the molar ratio of the elemental nickel introduced in the impregnation step f) to the elemental nickel introduced in the co-kneading step b) is from 0.1 to 10mol/mol, preferably from 0.3 to 5mol/mol, more preferably from 0.6 to 3mol/mol, more preferably from 0.8 to 1.8mol/mol.

In a specific embodiment according to the invention, in step f), a step of impregnating the catalyst precursor obtained in step d) or step e) additionally with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function is carried out. The organic compounds which can be introduced into this impregnation step f) are identical to those in the above-described co-kneading step b). Impregnation of the organic compound may be carried out by impregnation under dry conditions or in excess according to methods well known to those skilled in the art. Preferably, the impregnation is carried out under dry conditions, which comprise contacting the catalyst precursor with the solution in a volume of 0.25 to 1.5 times the pore volume of the support of the catalyst precursor to be impregnated. The method of preparing the nickel catalyst includes several embodiments. They differ in particular in the order of introduction of the organic compound and the nickel precursor, the operation of contacting the organic compound with the support being carried out after contacting the nickel precursor with the catalyst precursor obtained at the end of step d) or step e), or before contacting the nickel precursor with the catalyst precursor obtained at the end of step d) or step e), or simultaneously with impregnating the catalyst precursor obtained at the end of step d) or step e) with nickel.

Advantageously, the molar ratio of said organic compound introduced in step f) to the elemental nickel introduced in step f) is between 0.01 and 5.0mol/mol, preferably between 0.05 and 2.0mol/mol, more preferably between 0.1 and 1.5mol/mol, still more preferably between 0.3 and 1.2mol/mol, relative to the elemental nickel.

The one or more solutions containing at least one organic compound comprising at least one carboxylic acid functionality, or at least one alcohol functionality, or at least one ester functionality, or at least one amide functionality, or at least one amine functionality may be aqueous or organic (e.g., methanol or ethanol or phenol or acetone or toluene or Dimethylsulfoxide (DMSO)), or comprise a mixture of water and at least one organic solvent. The one or more organic compounds are at least partially dissolved in the one or more solutions in advance at a desired concentration. Preferably, the one or more solutions are aqueous or contain ethanol. More preferably, the solution is aqueous. The pH of the solution may be changed by the optional addition of an acid or base.

In a particular embodiment of step f) of impregnating the catalyst precursor obtained in step d) or step e) with at least one solution containing at least one nickel precursor and at least one solution containing at least one organic compound comprising at least one carboxylic acid function, or at least one alcohol function, or at least one ester function, or at least one amide function, or at least one amine function, the impregnating step f) comprises the sub-steps of:

Implementation of substep f 1) and substep f 2)

The method of preparing the nickel catalyst may include several embodiments. The latter may differ in particular in the order of introduction of the organic compound and the nickel precursor, the impregnation of the catalyst precursor obtained in step d) or step e) with the organic compound being carried out after the impregnation of the catalyst precursor obtained in step d) or step e) with the nickel precursor, or before the impregnation of the catalyst precursor obtained in step d) or step e) with the nickel precursor, or simultaneously with the impregnation of the catalyst precursor obtained in step d) or step e) with the nickel precursor.

The first embodiment comprises carrying out said step f 1) before said step f 2).

A second embodiment comprises carrying out said step f 2) before said step f 1).

Step f 1) of impregnating the catalyst precursor obtained in step d) or step e) with a nickel precursor and step f 2) of impregnating the catalyst precursor obtained in step d) or step e) with at least one solution containing at least one organic compound are each carried out at least once and may advantageously be carried out several times, optionally in the presence of a nickel precursor and/or an organic compound, which are the same or different in each step f 1) and/or step f 2), respectively, all possible combinations for carrying out step f 1) and step f 2) being within the scope of the invention.

A third embodiment comprises performing said step f 1) and said step f 2) simultaneously (co-contacting). This embodiment may advantageously comprise performing one or more steps f 1), optionally with the same or different nickel precursors being employed in each step f 1). In particular, one or more steps f 1) are advantageously before and/or after the co-contacting step. This embodiment may also include several co-contacting steps: step f 1) and step f 2) are carried out simultaneously several times, optionally in the presence of a nickel precursor and/or an organic compound, which are identical or different in each co-contacting step.

Preferably, an intermediate drying step may be carried out after each impregnation step. The intermediate drying step is carried out at a temperature below 250 ℃, preferably 15-240 ℃, more preferably 30-220 ℃, more preferably 50-200 ℃, even more preferably 70-180 ℃. Advantageously, when the intermediate drying step is carried out, an intermediate calcination step may be carried out. The intermediate calcination step is carried out at a temperature of 250-1000 ℃, preferably 250-750 ℃.

Advantageously, after each impregnation step, either the step of impregnating the catalyst precursor obtained in step d) or step e) with a nickel precursor, the step of impregnating the catalyst precursor obtained in step d) or step e) with an organic compound, or the step of impregnating the catalyst precursor obtained in step d) or step e) with a nickel precursor and an organic compound simultaneously, the impregnated catalyst precursor may optionally be cured before the intermediate drying step. Curing causes the solution to be uniformly distributed in the catalyst precursor. When the maturation step is carried out, said step is advantageously carried out at atmospheric or reduced pressure, under an inert atmosphere or under an oxygen-containing atmosphere or under an aqueous atmosphere, at a temperature between 10 ℃ and 50 ℃, preferably at ambient temperature. Generally, a maturation time of less than 48 hours, preferably 5 minutes to 5 hours is sufficient. Longer times are not precluded but do not necessarily contribute to improvement.

Step g): drying

Drying step g) is carried out at a temperature below 250 ℃, more preferably between 30 and 220 ℃, more preferably between 50 and 200 ℃, even more preferably between 70 and 180 ℃ for a period of typically between 10 minutes and 24 hours. Longer times are not precluded but do not necessarily contribute to improvement.

Step h): calcination (optional)

Optionally, at the end of the drying step g), the calcination step h) is carried out at a temperature of 250 ℃ to 1000 ℃, preferably 250 ℃ to 750 ℃, under an inert atmosphere or under an oxygen-containing atmosphere. The duration of the heat treatment is typically 15 minutes to 10 hours. Longer times are not precluded but do not necessarily contribute to improvement. Thus after this treatment, the nickel of the active phase was found to be in the oxide form.

Step i): by reduction with a reducing gas (optional)

Before the catalyst is used in the catalyst reactor and the hydrogenation process is carried out, after step g) or step h), at least one reduction treatment step i) is advantageously carried out in the presence of a reducing gas in order to obtain a catalyst comprising nickel at least partly in metallic form.

This treatment makes it possible to activate the catalyst and form metallic particles, in particular nickel in the zero-valent state. The reduction treatment may be carried out in situ or ex situ, that is to say after or before the loading of the catalyst into the hydrogenation reactor.

The reducing gas is preferably hydrogen. The hydrogen may be used as a pure substance or as a mixture (e.g. hydrogen/nitrogen, hydrogen/argon or hydrogen/methane mixture). In the case of hydrogen as a mixture, all ratios are conceivable.

The reduction treatment is carried out at a temperature of 120-500 ℃, preferably 150-450 ℃. When the catalyst is not passivated or is subjected to a reduction treatment prior to passivation, the reduction treatment is carried out at a temperature of 350-500 ℃, preferably 350-450 ℃. When the catalyst has been previously subjected to a deactivation treatment, the reduction treatment is generally carried out at a temperature of 120-350 ℃, preferably 150-350 ℃.

The duration of the reduction treatment is generally from 2 to 40 hours, preferably from 3 to 30 hours. The temperature is raised to the desired reduction temperature generally slowly, for example, set to 0.1-10 c/min, preferably 0.3-7 c/min.

The hydrogen flow in liters per hour per gram of catalyst is from 0.1 to 100 liters per hour per gram of catalyst, preferably from 0.5 to 10 liters per hour per gram of catalyst, more preferably from 0.7 to 5 liters per hour per gram of catalyst.

Step j): bluntChemical (optional)

Before the use of the catalyst according to the invention in the catalytic reactor, optionally before or after the reduction treatment step i) by sulfur or oxygen compounds or by CO ₂ A passivation step (step j) is performed on the catalyst. The passivation step may be performed ex situ or in situ. The passivation step is carried out by using methods known to those skilled in the art.

The step of performing passivation by sulfur can improve the selectivity of the catalyst and prevent thermal runaway during start-up of the fresh catalyst. Deactivation generally involves irreversibly poisoning the most active sites of nickel present on the fresh catalyst by sulfur compounds, thereby facilitating their selective attenuation of the catalyst activity. The passivation step is carried out by using methods known to the person skilled in the art, in particular for example by using one of the methods described in patent documents EP 0 466 567, US 5 153 163, FR 2 676 184, WO2004/098774 and EP 0 707 890. The sulfur compound is selected, for example, from the following compounds: thiophene, tetrahydrothiophene, alkyl monosulfide, such as dimethyl sulfide, diethyl sulfide, dipropyl sulfide and propyl methyl sulfide, or of the formula HO-R ₁ -S-S-R ₂ Organic disulfides of-OH, e.g. of the formula HO-C ₂ H ₄ -S-S-C ₂ H ₄ Dithiodiethanol of-OH (commonly referred to as DEODS). The sulfur content is generally between 0.1% and 2% by weight of said element relative to the weight of the catalyst.

By oxygen compounds or CO ₂ The step of carrying out the passivation is generally carried out after a reduction treatment carried out beforehand at high temperature (generally 350-500 ℃) so that the metallic phase of the catalyst can be maintained in the presence of air. The second reduction treatment is then typically carried out at a lower temperature (typically 120-350 ℃). The oxygen compound is typically air or any other oxygen containing stream.

Characterization of the catalyst

The catalyst obtained by the preparation process according to the invention is provided in the form of a composite comprising an oxide matrix having a content of calcined alumina greater than or equal to 90% by weight relative to the total weight of the matrix, in which an active phase comprising nickel is distributed. Resulting in the characteristics of the gel that produces alumina present in the oxide matrix and the texture characteristics obtained with the active phase impart to the catalyst its specific properties.

More particularly, the catalyst comprises an oxide matrix having a calcined alumina content of greater than or equal to 90 wt% relative to the total weight of the matrix and an active phase comprising nickel, the active phase being free of metals from group VIb, the nickel content being 15 wt% to 65 wt% relative to the total weight of the catalyst of the element, the active phase being provided in the form of nickel particles having a diameter of less than or equal to 18nm, the catalyst having a total pore volume of 0.01 to 1.0ml/g as measured by mercury porosimetry, a mesopore volume of greater than 0.01ml/g as measured by mercury porosimetry, a macropore volume of less than or equal to 0.6ml/g as measured by mercury porosimetry, a volume median macropore diameter of 3 to 25nm, a volume median macropore diameter of 50 to 1000nm, and a volume median macropore diameter of 25 to 350m ² SBET specific surface area per gram.

The nickel content is 15% to 65% by weight, preferably 18% to 55% by weight, preferably 20% to 50% by weight, particularly preferably 22% to 45% by weight, still more preferably 25% to 43% by weight, relative to the total weight of the catalyst. The Ni content was measured by X-ray fluorescence.

The nickel particles in the catalyst according to the invention have a size of less than 18nm, preferably less than 15nm, more preferably from 0.5 to 12nm, preferably from 1 to 8nm, more preferably from 1 to 6nm, still more preferably from 1.5 to 5nm. The "size of the nickel particles" is understood to mean the diameter of the nickel crystallites in their oxide form. The diameter of the nickel crystallites in oxide form was determined by X-ray diffraction from the width of the diffraction line lying at angle 2θ=43° (that is to say in crystallographic direction [200 ]) using the Scherrer relation. This method is used in the X-ray diffraction of polycrystalline samples or powders, which relates the full width at half maximum of the diffraction peak to the size of the particle and is described in detail in the following references: appl. Cryst (1978), 11, 102-113, "Scherrer after sixty years: A survey and some new results in the determination of crystallite size", j.i. Langford and a.j.c. Wilson.

The active phase of the catalyst is free of metals from group VIb. In particular, it does not contain molybdenum or tungsten.

Without wishing to be bound by any theory, when the catalyst obtained according to the preparation process of the invention is used in a selective hydrogenation process of polyunsaturated compounds or in a hydrogenation process of aromatic compounds according to the invention, it appears that the catalyst obtained by the preparation process according to the invention shows a good compromise between high pore volume, gao Dakong volume, high Ni content and small size nickel particles, thus making it at least as good performance quality in terms of hydrogenation activity as the performance quality of the catalysts known in the art.

The catalyst also comprises an oxide matrix having a calcined alumina content of greater than or equal to 90% by weight relative to the total weight of the matrix, optionally supplemented with SiO ₂ Equivalents and/or P ₂ O ₅ The equivalent is at most 10 wt.%, preferably less than 5 wt.%, very preferably less than 2 wt.% of silica and/or phosphorus relative to the total weight of the matrix. The silica and/or phosphorus may be introduced during synthesis of the alumina gel or during co-kneading by any technique known to those skilled in the art.

Still more preferably, the oxide matrix consists of alumina.

Preferably, the alumina present in the matrix is a transition alumina, such as gamma-alumina, delta-alumina, theta-alumina, chi-alumina, rho-alumina, or eta-alumina, alone or as a mixture. More preferably, the alumina is gamma transition alumina, delta transition alumina or theta transition alumina, alone or as a mixture.

The catalyst is generally present in all forms known to the person skilled in the art, for example in the form of beads (generally having a diameter of 1-8 mm), extrudates, blocks or hollow cylinders. Preferably, it consists of extrudates, the diameter of which is generally from 0.5 to 10mm, preferably from 0.8 to 3.2mm, very preferably from 1.0 to 2.5mm, and the average length is from 0.5 to 20mm. The "average diameter" of the extrudates is understood to mean the average diameter of the circles defined in the cross-section of these extrudates. The catalyst may advantageously be present in the form of a cylindrical, multi-lobed, trilobal or quadrulobal extrudate. Preferably, it is in the form of a trilobal or quadrulobal shape. The shape of the blade may be adjusted according to all methods known in the art.

The catalyst has a total pore volume of from 0.01 to 1.0ml/g, preferably from 0.05 to 0.9ml/g, preferably from 0.10 to 0.85ml/g, more preferably from 0.15 to 0.80ml/g, still more preferably from 0.20 to 0.75ml/g, even more preferably from 0.25 to 0.70 ml/g.

The catalyst advantageously has a macropore volume of less than or equal to 0.6ml/g, preferably from 0.03 to 0.50ml/g, more preferably from 0.05 to 0.40 ml/g.

The catalyst has a mesopore volume of at least 0.01ml/g, preferably from 0.05 to 0.40ml/g, more preferably from 0.10 to 0.35ml/g, more preferably from 0.15 to 0.33ml/g, more preferably from 0.20 to 0.30ml/g.

The median mesopore diameter is from 3 to 25nm, preferably from 4 to 23nm, particularly preferably from 6 to 20nm.

The catalyst has a median macropore diameter of 50-1000nm, preferably 80-900nm, more preferably 90-800 nm.

The catalyst has a particle size of 25-350m ² Preferably 40-300m ² /g, more preferably 60-280m ² BET specific surface area per gram.

Preferably, the catalyst exhibits low microporosity; very preferably, it does not have any microporosity.

Description of a method for selectively hydrogenating polyunsaturated Compounds

A further subject of the invention is a process for the selective hydrogenation of polyunsaturated compounds containing at least 2 carbon atoms per molecule, such as diolefins and/or acetylenic compounds and/or alkenylaromatic compounds (also known as styrenes), present in a hydrocarbon feedstock having a final boiling point of less than or equal to 300℃and, when said process is carried out in the liquid phase, at a temperature of from 0 to 300℃and a pressure of from 0.1 to 10MPa, from 0.1 to 10 hydrogen/(polyunsaturated compounds to be hydrogenated) Molar ratio of 0.1 to 200h ^-1 Is carried out at a hourly space velocity or, when the process is carried out in the gas phase, at a molar ratio of hydrogen/(polyunsaturated compounds to be hydrogenated) of from 0.5 to 1000 and from 100 to 40,000 hours ^-1 Is carried out in the presence of a catalyst obtained by the preparation process as described in the above description.

Monounsaturated organic compounds, such as ethylene and propylene, are the basis for the preparation of polymers, the preparation of plastics and the preparation of other chemicals with added value. These compounds are derived from natural gas, naphtha or gas oil which is treated by steam cracking or catalytic cracking processes. These processes are carried out at elevated temperatures and produce, in addition to the desired monounsaturated compounds, polyunsaturated organic compounds, such as acetylene, propadiene and methylacetylene (or propyne), 1, 2-butadiene and 1, 3-butadiene, vinylacetylene and ethylacetylene and other polyunsaturated compounds, whose boiling points correspond to the C5+ fraction (hydrocarbon compounds having at least 5 carbon atoms), in particular diolefins or styrenes or indenes. These polyunsaturated compounds are highly reactive and lead to side reactions in the polymerized units. Therefore, these fractions must be removed before they can be used economically.

Selective hydrogenation is the primary treatment developed for the specific removal of unwanted polyunsaturated compounds from these hydrocarbon feedstocks. This makes it possible to convert polyunsaturated compounds into the corresponding olefins or aromatics while avoiding their complete saturation and thus the formation of the corresponding alkanes or cycloalkanes. In the case of steam cracking of gasoline used as feedstock, selective hydrogenation can also selectively hydrogenate alkenyl aromatic compounds to give aromatics while avoiding hydrogenation of aromatic nuclei.

The hydrocarbon feedstock treated in the selective hydrogenation process has a final boiling point of less than or equal to 300 ℃ and contains at least 2 carbon atoms per molecule and at least one polyunsaturated compound. By "polyunsaturated compound" is understood a compound comprising at least one acetylenic function and/or at least one diene function and/or at least one alkenyl aromatic function.

More specifically, the feedstock is selected from the group consisting of a steam cracked C2 fraction, a steam cracked C2-C3 fraction, a steam cracked C4 fraction, a steam cracked C5 fraction, and a steam cracked gasoline (also referred to as pyrolysis gasoline or C5+ fraction).

The steam cracked C2 fraction advantageously used to carry out the selective hydrogenation process according to the invention has, for example, the following composition: 40 wt% to 95 wt% ethylene and about 0.1 wt% to 5 wt% acetylene, the balance being essentially ethane and methane. In some steam cracked C2 fractions, 0.1 wt% to 1 wt% of C3 compounds may also be present.

The steam cracked C3 fraction advantageously used to carry out the selective hydrogenation process according to the invention has, for example, the following average composition: about 90 wt% propylene and about 1 wt% to 8 wt% propadiene and methylacetylene, the balance being substantially propane. In some C3 fractions, 0.1% to 2% by weight of C2 compounds and C4 compounds may also be present.

The C2-C3 fraction can also be advantageously used for carrying out the selective hydrogenation process according to the invention. It has, for example, the following composition: about 0.1 wt% to about 5 wt% acetylene, about 0.1 wt% to about 3 wt% allene and methylacetylene, about 30 wt% ethylene and about 5 wt% propylene, the balance being essentially methane, ethane and propane. The feedstock may also contain 0.1 wt% to 2 wt% of C4 compounds.

The steam cracked C4 fraction advantageously used to carry out the selective hydrogenation process according to the invention has, for example, the following average composition by weight: 1% by weight of butane, 46.5% by weight of butene, 51% by weight of butadiene, 1.3% by weight of vinylacetylene and 0.2% by weight of butyne. In some C4 fractions, 0.1 wt% to 2 wt% of C3 compounds and C5 compounds may also be present.

The steam cracked C5 fraction advantageously used to carry out the selective hydrogenation process according to the invention has, for example, the following composition: 21 wt.% pentane, 45 wt.% pentene and 34 wt.% pentadiene.

The steam cracked gasoline or pyrolysis gasoline advantageously used in carrying out the selective hydrogenation process according to the present invention corresponds to a hydrocarbon fraction having a boiling point generally ranging from 0 to 300 ℃, preferably from 10 to 250 ℃. Polyunsaturated hydrocarbons to be hydrogenated present in the steam cracked gasoline are in particular diolefins compounds (butadiene, isoprene, cyclopentadiene, etc.), styrenes (styrene, alpha-methylstyrene, etc.), and indenes (indenes, etc.). Steam cracked gasoline typically contains C5-C12 fractions with trace amounts of C3, C4, C13, C14, and C15 (e.g., 0.1 wt.% to 3 wt.% for each of these fractions). For example, a feedstock formed from pyrolysis gasoline typically has the following composition: from 5% to 30% by weight of saturated compounds (alkanes and cycloalkanes), from 40% to 80% by weight of aromatic compounds, from 5% to 20% by weight of mono-olefins, from 5% to 40% by weight of di-olefins and from 1% to 20% by weight of alkenyl aromatic compounds, these compounds adding up to 100%. It also contains 0 to 1000 ppm by weight of sulfur, preferably 0 to 500 ppm by weight of sulfur.

Preferably, the polyunsaturated hydrocarbon feedstock treated in accordance with the selective hydrogenation process of the present invention is a steam cracked C2 fraction or a steam cracked C2-C3 fraction or steam cracked gasoline.

The purpose of the selective hydrogenation process according to the invention is to remove the polyunsaturated hydrocarbons present in the feedstock to be hydrogenated without hydrogenating the monounsaturated hydrocarbons. For example, when the feedstock is a C2 fraction, the purpose of the selective hydrogenation process is to selectively hydrogenate acetylene. When the feedstock is a C3 cut, the purpose of the selective hydrogenation process is to selectively hydrogenate propadiene and methylacetylene. In the case of the C4 cut, the objective is to remove butadiene, vinyl Acetylene (VAC) and butyne; in the case of the C5 fraction, the aim is to remove pentadienes. When the feedstock is steam cracked gasoline, the purpose of the selective hydrogenation process is to selectively hydrogenate the polyunsaturated hydrocarbons present in the feedstock to be treated so as to partially hydrogenate the diolefin compounds to mono-olefins and to partially hydrogenate the styrenes and indenes to the corresponding aromatic compounds while avoiding hydrogenation of the aromatic nuclei.

The technical embodiment of the selective hydrogenation process is carried out, for example, by injecting the polyunsaturated hydrocarbon feedstock and hydrogen as ascending or descending streams into at least one fixed bed reactor. The reactor may be of isothermal or adiabatic type. Adiabatic reactors are preferred. The polyunsaturated hydrocarbons of the feedstock can advantageously be diluted by one or more reinjections of the effluent obtained from said reactor in which the selective hydrogenation reaction takes place, at different points of the reactor situated between the inlet and outlet of the reactor, so as to limit the temperature gradient in the reactor. The technical implementation of the selective hydrogenation process according to the invention can also advantageously be carried out by loading at least the supported catalyst in a reactive distillation column or in a reactor-exchanger or in a slurry-type reactor. The hydrogen stream may be introduced simultaneously with the feedstock to be hydrogenated and/or at one or more different points in the reactor.

The selective hydrogenation of the steam cracked C2 fraction, C2-C3 fraction, C4 fraction, C5 fraction and C5+ fraction may be carried out in the gas phase or in the liquid phase, preferably in the liquid phase for the C3 fraction, C4 fraction, C5 fraction and C5+ fraction, preferably in the gas phase for the C2 fraction and C2-C3 fraction. The liquid phase reaction can reduce energy costs and extend the cycle time of the catalyst.

In general, for processes carried out in the liquid phase, the selective hydrogenation of hydrocarbon feedstocks which contain polyunsaturated compounds containing at least 2 carbon atoms per molecule and having a final boiling point of less than or equal to 300℃is carried out at temperatures of from 0 to 300℃at pressures of from 0.1 to 10MPa, hydrogen/(polyunsaturated compounds to be hydrogenated) molar ratios of from 0.1 to 10, for from 0.1 to 200h ^-1 Is carried out at a space velocity HSV (defined as the ratio of the volumetric flow of the feedstock to the volume of the catalyst) or, for processes carried out in the gas phase, the selective hydrogenation is carried out at a molar ratio of hydrogen/(polyunsaturated compound to be hydrogenated) of from 0.5 to 1000 and at a time of from 100 to 40,000 h ^-1 Is carried out at a space-time velocity HSV.

In one embodiment according to the invention, when carrying out the selective hydrogenation process in which the feedstock is steam cracked gasoline comprising polyunsaturated compounds, the (hydrogen)/(polyunsaturated compounds to be hydrogenated) molar ratio is generally from 0.5 to 10, preferably from 0.7- 5.0, more preferably 1.0 to 2.0, at a temperature of 0 to 200 ℃, preferably 20 to 200 ℃, more preferably 30 to 180 ℃, and a space velocity (HSV) of usually 0.5 to 100h ^-1 Preferably 1 to 50h ^-1 The pressure is usually 0.3 to 8.0MPa, preferably 1.0 to 7.0MPa, more preferably 1.5 to 4.0MPa.

More preferably, a selective hydrogenation process is carried out in which the feedstock is steam cracked gasoline comprising polyunsaturated compounds, the hydrogen/(polyunsaturated compounds to be hydrogenated) molar ratio being from 0.7 to 5.0, the temperature being from 20 to 200℃and the Hourly Space Velocity (HSV) generally being from 1 to 50h ^-1 The pressure is 1.0-7.0MPa.

More preferably, a selective hydrogenation process is carried out in which the feedstock is steam cracked gasoline comprising polyunsaturated compounds, the hydrogen/(polyunsaturated compounds to be hydrogenated) molar ratio being from 1.0 to 2.0, the temperature being from 30 to 180℃and the Hourly Space Velocity (HSV) generally being from 1 to 50h ^-1 The pressure is 1.5-4.0MPa.

The hydrogen flow is adjusted to have an amount sufficient to theoretically hydrogenate all polyunsaturated compounds and maintain an excess of hydrogen at the reactor outlet.

In another embodiment according to the invention, when carrying out the selective hydrogenation process in which the feedstock is a steam-cracked C2 fraction and/or a steam-cracked C2-C3 fraction comprising polyunsaturated compounds, the molar ratio of (hydrogen)/(polyunsaturated compounds to be hydrogenated) is generally from 0.5 to 1000, preferably from 0.7 to 800, the temperature is from 0 to 300 ℃, preferably from 15 to 280 ℃, and the space-time-velocity (HSV) is generally from 100 to 40,000h ^-1 Preferably 500-30000h ^-1 The pressure is generally from 0.1 to 6.0MPa, preferably from 0.2 to 5.0MPa.

Description of the method for hydrogenating aromatic Compounds

Another subject of the invention is a process for the hydrogenation of at least one aromatic or polyaromatic compound present in a hydrocarbon feedstock having a final boiling point of less than or equal to 650 ℃, generally ranging from 20 to 650 ℃, preferably ranging from 20 to 450 ℃. The hydrocarbon feedstock containing at least one aromatic or polyaromatic compound may be selected from the following petroleum or petrochemical fractions: reformate from catalytic reforming, kerosene, light gas oil, heavy gas oil, cracked distillates, such as FCC cycle oil, coker gas oil or hydrocracked distillates.

The content of aromatic or polyaromatic compounds present in the hydrocarbon feedstock treated in the hydrogenation process according to the invention is generally from 0.1% to 80% by weight, preferably from 1% to 50% by weight, particularly preferably from 2% to 35% by weight, based on the total weight of the hydrocarbon feedstock. The aromatic compounds present in the hydrocarbon feedstock are, for example, benzene or alkylaromatic compounds, such as toluene, ethylbenzene, o-xylene, m-xylene or p-xylene, or aromatic compounds (polyaromatic compounds) having a plurality of aromatic nuclei, such as naphthalene.

The sulfur or chlorine content of the feedstock is generally less than 5000 ppm by weight, preferably less than 100 ppm by weight, particularly preferably less than 10 ppm by weight of sulfur or chlorine.

Technical examples of processes for hydrogenating aromatic or polyaromatic compounds are carried out, for example, by injecting a hydrocarbon feedstock and hydrogen as ascending or descending streams into at least one fixed bed reactor. The reactor may be of isothermal or adiabatic type. Adiabatic reactors are preferred. The hydrocarbon feedstock may advantageously be diluted by one or more reinjections of the effluent obtained from said reactor in which the hydrogenation of aromatic compounds takes place, at different points of the reactor between the inlet and outlet of the reactor, so as to limit the temperature gradient in the reactor. The technical implementation of the process for hydrogenating aromatic compounds according to the invention can also advantageously be carried out by loading at least the supported catalyst in a reactive distillation column or in a reactor-exchanger or in a slurry-type reactor. The hydrogen stream may be introduced simultaneously with the feedstock to be hydrogenated and/or at one or more different points in the reactor.

The hydrogenation of aromatic or polyaromatic compounds may be carried out in the gas phase or in the liquid phase, preferably in the liquid phase. In general, the hydrogenation of aromatic or polyaromatic compounds containing aromatic or polyaromatic compounds and having a final boiling point of less than or equal to 650 ℃, generally from 20 to 650 ℃, preferably from 20 to 450 ℃, is carried out at a temperature of from 30 to 350 ℃, preferably from 50 to 325 ℃, at a pressure of from 0.1 to 20MPa, preferably from 0.5 to 10MPa, at a molar ratio of hydrogen/(aromatic compound to be hydrogenated) of from 0.1 to 10, for from 0.05 to 50h ^-1 Preferably 0.1 to 10h ^-1 Is carried out at a space-time velocity HSV.

The hydrogen flow is adjusted to have an amount sufficient to theoretically hydrogenate all aromatics and maintain an excess of hydrogen at the reactor outlet.

The conversion of aromatic or polyaromatic compounds is generally greater than 20 mole%, preferably greater than 40 mole%, more preferably greater than 80 mole%, particularly preferably greater than 90 mole% of the aromatic or polyaromatic compounds present in the hydrocarbon feedstock. Conversion is calculated by dividing the difference between the total moles of aromatic or polyaromatic compound in the hydrocarbon feedstock and the aromatic or polyaromatic compound in the product by the total moles of aromatic or polyaromatic compound in the hydrocarbon feedstock.

According to a particular alternative form of the process of the invention, a process is carried out for hydrogenating benzene of a hydrocarbon feedstock, for example reformate obtained from a catalytic reforming unit. The benzene content of the hydrocarbon feedstock is generally from 0.1% to 40% by weight, preferably from 0.5% to 35% by weight, particularly preferably from 2% to 30% by weight, based on the total weight of the hydrocarbon feedstock.

The sulfur or chlorine content of the feedstock is generally less than 10 ppm by weight, preferably less than 2 ppm by weight, of sulfur or chlorine, respectively.

The hydrogenation of benzene present in the hydrocarbon feedstock may be carried out in the gas phase or in the liquid phase, preferably in the liquid phase. When carried out in the liquid phase, a solvent such as cyclohexane, heptane or octane may be present. In general, the hydrogenation of benzene is carried out at a temperature of from 30 to 250℃and preferably from 50 to 200℃and more preferably from 80 to 180℃and a pressure of from 0.1 to 10MPa and preferably from 0.5 to 4MPa and a hydrogen/(benzene) molar ratio of from 0.1 to 10 for from 0.05 to 50h ^-1 Preferably 0.5-10h ^-1 Is carried out at a space-time velocity HSV.

The conversion of benzene is generally greater than 50 mol%, preferably greater than 80 mol%, more preferably greater than 90 mol% and particularly preferably greater than 98 mol%.

The invention is illustrated by the following examples.

Detailed Description

Example 1: preparation of aqueous solutions of Ni precursors

By adding 52g of nickel nitrate (Ni (NO) ₃ ) ₂ ·6H ₂ O, supplied by Strem Chemicals) was dissolved in a volume of 13ml of distilled water to prepare an aqueous solution (solution S) of Ni precursors for preparing catalysts C to F. A solution S having a NiO concentration of 20.6 wt% relative to the weight of the solution was obtained.

Example 2: preparation of calcined porous alumina (according to embodiment 2)

Alumina a was synthesized in a laboratory reactor having a capacity of about 7000 ml. The synthesis is carried out at 70℃with stirring, divided into six steps, hereinafter referred to as a1 ') to a 6'). The aim was to prepare a solution with a concentration of 5 liters fixed at 27g/l alumina in the final suspension (obtained at the end of step a3 ') and the first step (a 1') had a contribution of 2.1% of the total amount of alumina.

a 1') dissolution: 70ml of aluminum sulfate Al ₂ (SO ₄ ) ₃ A reactor containing 1679ml of water (water heel) was added in one portion. The pH change (which remains at 2.5-3) was monitored for 10 minutes. This step facilitates the introduction of alumina in an amount of 2.1% relative to the total weight of alumina formed at the end of the gel synthesis. The solution was stirred for 10 minutes.

a2') pH adjustment: about 70mL of sodium aluminate NaAlOO was gradually added. The aim is to reach a pH of 7-10 in a period of 5-15 minutes.

a3') coprecipitation: within 30 minutes, the following substances were added to the suspension obtained at the end of step a 2'):

1020ml of aluminum sulfate Al ₂ (SO ₄ ) ₃ I.e., the flow rate was 34 ml/min,

1020ml of sodium aluminate NaAlOO, i.e. a flow rate of 34 ml/min,

1150ml of distilled water, i.e. a flow rate of 38.3ml/min.

The pH value is 8.7-9.9.

a 4') filtration: the suspension obtained at the end of step a 3') was filtered by displacement on a device of the sintered BuchnerP 4 type and washed several times with distilled water. Alumina gel was obtained.

a 5') drying: the alumina gel obtained at the end of step a 4') was dried in an oven at 200 ℃ for 16 hours.

a 6') heat treatment: the powder obtained at the end of step a 5') was then calcined at 750℃for 2 hours under an air stream of 1l/h/g alumina gel to complete the boehmite to alumina conversion. Alumina a is then obtained.

Example 3 (comparative): preparation of catalyst C by two impregnations with Nickel nitrate

Catalyst C was prepared by impregnating alumina a described in example 2 with nickel nitrate twice in succession. The first catalyst C' was prepared by impregnation with a solution S of Ni precursor under dry conditions of alumina a.

Alumina a was synthesized by following the six steps a1 ') to a 6') of example 2 described above. The operating conditions are exactly the same. However, the step of shaping the dried alumina gel produced in step a5 ') is interposed between step a5 ') and step a6 '). The shaping of the powder was carried out on a "Brabender" kneader with an acid content of 1% (total acid content, expressed relative to dry alumina), a degree of neutralization of 20% and an acid and alkaline loss on ignition of 62% and 64%, respectively. Extrusion was then carried out on a piston extruder through a die having a diameter of 2.1 mm. After extrusion, the extrudate was dried at 80 ℃ for 16 hours. At the end of the calcination step a 6'), an extrudate of alumina a is obtained.

The solution S prepared in example 1 was impregnated under dry conditions onto 10g of alumina A. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃under an air stream of 1 l/h/g of catalyst for 2 hours.

The calcined catalyst C' thus prepared contained 22.3 wt.% elemental nickel relative to the total weight of the catalyst.

The catalyst C' was then impregnated once more with the same Ni precursor solution S. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃under an air stream of 1 l/h/g of catalyst for 2 hours. This gives catalyst C. The calcined catalyst C thus prepared contained 33.2 wt% elemental nickel relative to the total weight of the catalyst, and it had nickel oxide crystallites having an average diameter (measured by X-ray diffraction from the width of the diffraction line at angle 2θ=43°) of 16.4nm. Other structural features of catalyst C are listed in table 1 below.

Example 4 (comparative): catalyst D was prepared by co-kneading followed by impregnation, with at the end of the co-kneading step Too low Ni content (8%)

Catalyst D was prepared by co-kneading alumina a and nickel nitrate, followed by impregnation with nickel nitrate. The first catalyst D' was prepared from the solution S of alumina a and Ni precursors prepared as described above according to the following four steps:

co-kneading: a "Brabender" kneader having a vessel of 80ml and a kneading rate of 30 revolutions per minute was used. The alumina a powder was placed in a vessel of a kneader. The solution S of Ni precursor was then added in one portion at 15 revolutions per minute using a syringe. After the paste was obtained, the kneading was kept at 50 rpm for 15 minutes.

-extrusion: the paste thus obtained was introduced into a piston extruder and extruded at 50mm/min through a die having a diameter of 2.1 mm.

-drying: the extrudate thus obtained was then dried in an oven at 80 ℃ for 16 hours. A dried catalyst was obtained.

-heat treatment: the dried catalyst was then calcined in a tube furnace at 450℃for 2 hours (temperature gradient 5℃per minute) under an air stream of 1l/h/g of catalyst.

Calcined catalyst D' was then obtained, which contained 8 wt% elemental nickel relative to the total weight of the catalyst.

The catalyst D' was then impregnated with the same Ni precursor solution S under dry conditions. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃for 2 hours under an air stream of 1l/h/g of catalyst. This gives catalyst D. The calcined catalyst D thus prepared contained 28.7 wt% elemental nickel relative to the total weight of the catalyst, and it had nickel oxide crystallites having an average diameter (measured by X-ray diffraction from the width of the diffraction line at angle 2θ=43°) of 15.1nm. Other structural features of catalyst D are listed in table 1 below.

The Ni content obtained at the end of the co-kneading step is lower than the preferred range (8% by weight); thus, the final Ni content relative to the final catalyst is lower than the expected optimum.

Example 5: catalyst E was prepared by co-kneading followed by impregnation, with too high of a degree at the end of the co-kneading step Ni content (36%)

Catalyst E was prepared by co-kneading alumina A and nickel nitrate followed by impregnation with nickel nitrate. The first catalyst E' was prepared from the solution S of alumina a and Ni precursors prepared as described above according to the following four steps:

co-kneading: a "Brabender" kneader having a vessel of 80ml and a kneading rate of 30 revolutions per minute was used. The alumina a powder was placed in a vessel of a kneader. The solution S of Ni precursor was then added in one portion with a syringe at 15 rpm for about 15 minutes while heating to drain water. After the paste was obtained, the kneading was kept at 50 rpm for 15 minutes.

A calcined catalyst E' was then obtained, which contained 36% by weight of elemental nickel with respect to the total weight of the catalyst.

The catalyst E' was then impregnated with a solution S of the same Ni precursor under dry conditions. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃for 2 hours under an air stream of 1l/h/g of catalyst. This gives catalyst E. The calcined catalyst E thus prepared contained 39.4 wt% elemental nickel relative to the total weight of the catalyst, and it had nickel oxide crystallites having an average diameter (measured by X-ray diffraction from the width of the diffraction line at angle 2θ=43°) of 20.5nm. Other structural features of catalyst E are listed in Table 1 below. The Ni content obtained at the end of the co-kneading step was higher than the preferred range (36 wt%) and was found to be not very different with respect to the final Ni content of the final catalyst after the impregnation step.

Example 6 (according to the invention): preparation of catalyst F by Co-kneading and then impregnation

Catalyst F was prepared by co-kneading alumina a and nickel nitrate, followed by impregnation with nickel nitrate. The first catalyst F' was prepared from the solution S of alumina a and Ni precursors prepared as described above according to the following four steps:

co-kneading: a "Brabender" kneader having a vessel of 80ml and a kneading rate of 30 revolutions per minute was used. The alumina a powder was placed in a vessel of a kneader. The solution S of Ni precursor was then added at once at 15 rpm for about 10 minutes using a syringe while heating to drain water. After the paste was obtained, the kneading was kept at 50 rpm for 15 minutes.

A calcined catalyst F' was then obtained, which contained 28% by weight of elemental nickel with respect to the total weight of the catalyst.

The catalyst F' was then impregnated with a solution S of the same Ni precursor under dry conditions. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃for 2 hours under an air stream of 1l/h/g of catalyst. This gives rise to catalyst F. The calcined catalyst F thus prepared contained 41.6% by weight of elemental nickel relative to the total weight of the catalyst, and it had nickel oxide crystallites having an average diameter (measured by X-ray diffraction from the width of the diffraction line lying at angle 2θ=43°) of 14.2nm. Other structural features of catalyst F are listed in Table 1 below.

The Ni content obtained at the end of the kneading step was in the preferable range (28 wt%). The catalyst prepared conforms to the catalyst described in the present patent application, and can achieve optimal performance quality.

Example 7 (according to the invention): by co-kneading in the presence of malonic acid in two steps of co-kneading and impregnating Kneading and then impregnating to prepare catalyst G

By adding 89.0g of nickel nitrate Ni (NO ₃ ) ₂ ·6H ₂ O (supplied by Strem Chemicals) and 19.1g malonic acid (CAS 141-82-2, supplied by Fluka) were dissolved in 20ml of demineralized water to prepare an aqueous solution S'. A solution S' was obtained whose NiO concentration was 20.6% by weight relative to the weight of the solution, and whose { malonic acid/nickel } molar ratio was equal to 0.6.

Catalyst G was prepared by co-kneading alumina a with a solution S' of nickel nitrate and malonic acid, followed by impregnation with nickel nitrate. The first catalyst G 'was prepared from the alumina a prepared as described above and the solution S' according to the following four steps:

co-kneading: a "Brabender" kneader having a vessel of 80ml and a kneading rate of 30 revolutions per minute was used. The alumina a powder was placed in a vessel of a kneader. The solution S' of Ni precursor and malonic acid was then added in one portion at 15 rpm for about 10 minutes using a syringe while heating to drain the water. After the paste was obtained, the kneading was kept at 50 rpm for 15 minutes.

A calcined catalyst G' was then obtained, which contained 28% by weight of elemental nickel relative to the total weight of the catalyst.

The catalyst G 'was then impregnated with the same Ni precursor and malonic acid solution S' under dry conditions. The solid thus obtained was subsequently dried in an oven at 120℃for 16 hours and then calcined at 450℃for 2 hours under an air stream of 1l/h/g of catalyst. This gives catalyst G. The calcined catalyst G thus prepared contained 41.6 wt% elemental nickel relative to the total weight of the catalyst, and it had nickel oxide crystallites having an average diameter (measured by X-ray diffraction from the width of the diffraction line at angle 2θ=43°) of 4.7nm. Other structural features of catalyst G are listed in table 1 below.

The Ni content obtained at the end of the kneading step was in the preferable range (28 wt%). The prepared catalyst accords with the catalyst with the best characteristic, and can realize the best performance quality.

Table 1: characteristics of catalyst C, catalyst D and catalyst E (not according to the preparation method according to the invention) and catalyst F and catalyst G (according to the invention)

Catalyst	C	D	E	F	G
							Comparison	Comparison	Comparison	According to the invention	According to the invention
Introduction form 1 of Ni	Dipping	Co-kneading	Co-kneading	Co-kneading	Co-kneading + additive
						Ni (wt.%) of stage 1	22.3	8	36	28	28
Total pore volume of catalyst 1 (ml/g)	0.57	0.78	0.61	0.68	0.68
						Mesoporous volume of catalyst 1 (ml/g)	0.37	0.50	0.33	0.40	0.40
Macropore volume (ml/g) of catalyst 1	0.20	0.28	0.28	0.28	0.28
						Form 2 of Ni introduction	Dipping	Dipping	Dipping	Dipping	Impregnating and additive
Ni (wt.%) of the final catalyst	33.2	28.7	39.4	41.6	41.6
						BET surface area (m) of the final catalyst ² /g)	175	189	142	141	144
Total pore volume of final catalyst (ml/g)	0.33	0.53	0.47	0.49	0.50
						Mesoporous volume of final catalyst (ml/g)	0.24	0.29	0.22	0.24	0.25
Median mesoporous diameter (nm) of final catalyst	10.5	7.1	6.2	7.0	7.1
						Macropore volume (ml/g) of final catalyst	0.09	0.24	0.25	0.25	0.25
Size (nm) of NiO crystallites of the final catalyst	16.4	15.1	20.5	14.2	4.7

Example 8: evaluation of catalyst C, catalyst D, catalyst E, catalyst F and catalyst G in the presence of styrene and of iso In the selective hydrogenation of mixtures of pentadienesCatalytic properties

Catalysts C, D, E, F and G described in the examples above were tested for selective hydrogenation of mixtures containing styrene and isoprene.

The composition of the feedstock to be selectively hydrogenated is as follows: 8% by weight of styrene (supplied by Sigma Aldrich with 99% purity), 8% by weight of isoprene (supplied by Sigma Aldrich with 99% purity) and 84% by weight of n-heptane (solvent) (supplied by VWR with >99%Chromanorm HPLC purity). The feedstock also contains very small amounts of sulfur compounds: 10 weight ppm of sulfur introduced in the form of pentamercaptan (provided by Fluka, purity > 97%) and 100 weight ppm of sulfur introduced in the form of thiophene (provided by Merck, purity 99%). The composition corresponds to the initial composition of the reaction mixture. This mixture of model molecules represents pyrolysis gasoline.

The selective hydrogenation reaction was carried out in a 500ml stainless steel autoclave equipped with a magnetically driven mechanical stirrer and capable of operating at a maximum pressure of 100 bar (10 MPa) and a temperature of 5-200 ℃.

The catalyst was reduced ex situ in an amount of 3ml at 400℃for 16 hours (temperature gradient 1℃per minute) under a hydrogen stream of 1l/h/g catalyst before it was introduced into the autoclave, and then transferred into the autoclave, and air was vented. After addition of 214ml of n-heptane (provided by VWR cube, purity > 99%Chromanorm HPLC), the autoclave was closed, purged, then pressurized under 35 bar (3.5 MPa) of hydrogen and brought to a test temperature equal to 30 ℃. At time t=0, about 30g of a mixture containing styrene, isoprene, n-heptane, pentanethiol and thiophene was introduced into the autoclave. The reaction mixture then had the above-described composition and stirring was started at 1600 revolutions per minute. A storage tank located upstream of the reactor was used to keep the pressure in the autoclave constant at 35 bar (3.5 MPa).

The progress of the reaction was monitored by sampling from the reaction medium at regular time intervals: styrene is hydrogenated to ethylbenzene without hydrogenating the aromatic ring, and isoprene is hydrogenated to methylbutene. If the reaction is prolonged beyond that necessary And then the methyl butene is hydrogenated to obtain isopentane. In addition, hydrogen consumption was monitored over time by pressure drop in a storage tank located upstream of the reactor. Catalytic activity is expressed as H consumed per gram of Ni per minute ₂ Molar number of (3).

The catalytic activities measured for catalyst C, catalyst D, catalyst E, catalyst F and catalyst G are given in table 2 below. They refer to the catalytic activity measured for catalyst C (A _HYD1 )。

Table 2: selective hydrogenation of mixtures containing styrene and isoprene (A) _HYD1 ) And toluene hydrogenation (A) _HYD2 ) Comparison of performance quality of (C)

Catalyst	Preparation method	Ni content (weight) relative to the final catalyst % by weight)	Average size of NiO crystallite (nm)	A _HYD1 (%)	A _HYD2 (%)
						C (not according to the invention) Ming dynasty)	Dipping+dipping	33.2	16.4	100	100
D (not according to the invention) Ming dynasty)	Co-kneading (8% Ni) + impregnation	28.7	15.1	86	91
						E (not according to the invention) Ming dynasty)	Co-kneading (36% Ni) + impregnation	39.4	20.5	94	96
F (according to the invention)	Co-kneading (28% Ni) + impregnation	41.6	14.2	131	144
						G (according to the invention)	Co-kneading in the Presence of malonic acid (28% Ni) +in the Presence of malonic acid Impregnation under	41.6	6.2	288	302

This clearly demonstrates the improved performance qualities of catalysts F and G prepared according to the invention, in particular the effect of taking the first step of co-kneading of the active phase in the presence or absence of organic additives, rather than taking the impregnation step. The content added in this co-kneading step is practically 10% to 35% by weight, 28% by weight, which makes it possible to maintain the high porosity required for the second impregnation step, achieving an optimal addition to a Ni content of at least 40% by weight. Furthermore, catalyst G is prepared by adding organic additives, which can also simultaneously obtain catalysts with not only high Ni loading but also very small Ni crystallite size (about 5 nm), which in turn further improves the catalytic performance quality.

Catalyst C prepared by two impregnations could not obtain a high Ni content. This is because the porosity of the catalyst resulting from the co-kneading step is too low. Catalyst D and catalyst E prepared at the end of the co-kneading step had too low (8 wt%) Ni content, which makes it impossible to obtain a sufficiently high final Ni content, or catalyst D and catalyst E prepared at the end of the co-kneading step had too high (36 wt%) Ni content, and then the final Ni content was slightly high, but a catalyst having the best characteristics (the size of NiO particles was too high and the porosity of the catalyst was insufficient) could not be obtained.

Example 9: evaluation of catalyst C, catalyst D, catalyst E, catalyst F and catalyst G in the hydrogenation of toluene Catalytic properties

Catalysts C, D, E, F and G described in the above examples were also tested for the hydrogenation of toluene.

The selective hydrogenation reaction was carried out in the same autoclave as described in example 8.

The catalyst was reduced ex situ in an amount of 2ml at 400℃for 16 hours (temperature gradient 1℃per minute) under a hydrogen stream of 1l/h/g catalyst before it was introduced into the autoclave, and then transferred into the autoclave, and air was vented. After addition of 216ml of n-heptane (provided by VWR, purity > 99%Chromanorm HPLC), the autoclave was closed, purged, then pressurized under 35 bar (3.5 MPa) of hydrogen and brought to a test temperature equal to 80 ℃. At time t=0, about 26g of toluene (provided by SDS, purity > 99.8%) was introduced into the autoclave (the starting composition of the reaction mixture was then 6 wt% toluene/94 wt% n-heptane) and stirring was started at 1600 revolutions per minute. A storage tank located upstream of the reactor was used to keep the pressure in the autoclave constant at 35 bar (3.5 MPa).

The progress of the reaction was monitored by sampling from the reaction medium at regular time intervals: toluene was completely hydrogenated to give methylcyclohexane. Hydrogen consumption was also monitored over time by pressure drop in a storage tank located upstream of the reactor. Catalytic activity is expressed as H consumed per gram of Ni per minute ₂ Molar number of (3).

The catalytic activities measured for catalyst C, catalyst D, catalyst E, catalyst F and catalyst G are given in table 2 above. They refer to the catalytic activity measured for catalyst C (A _HYD2 )。

This clearly demonstrates the improved performance qualities of catalysts F and G prepared according to the invention, in particular the effect of taking the first step of co-kneading of the active phase in the presence or absence of organic additives, rather than taking the impregnation step.

Claims

1. Method for preparing a catalyst comprising an oxide matrix having a calcined alumina content of greater than or equal to 90 wt% relative to the total weight of the matrix and an active phase comprising nickel, the active phase being free of metals from group VIb and having a nickel content of 15 wt% to 65 wt% relative to the total weight of the catalyst, the active phase being provided in the form of nickel particles having a diameter of less than or equal to 18nm, the catalyst having a total pore volume of 0.01 to 1.00 mL/g as measured by mercury porosimetry, a mesopore volume of greater than 0.01 mL/g as measured by mercury porosimetry, a macropore volume of less than or equal to 0.6mL/g as measured by mercury porosimetry, a volume mesopore diameter of 3 to 25nm, a volume median diameter of 50 to 1000nm and a volume median diameter of 25 to 350m ² SBET specific surface area per gram, the method comprising the steps of:

a) Preparing calcined porous alumina;

b) Kneading the calcined porous alumina obtained in step a) with at least one solution comprising at least one nickel precursor, which is nickel nitrate, nickel chloride, nickel acetate or basic nickel carbonate, to obtain a paste at the desired nickel concentration in order to obtain a nickel content of 10% to 35% by weight relative to the total weight of the catalyst, with respect to the dried or calcined catalyst;

c) Shaping the paste obtained in step b);

e) Optionally, subjecting the dried catalyst precursor obtained in step d) to a heat treatment at a temperature of 250-1000 ℃ in the presence or absence of water to obtain a calcined catalyst precursor;

f) Impregnating the dried catalyst precursor obtained in step d) or the calcined catalyst precursor obtained in step e) with at least one solution containing at least one nickel precursor to obtain an impregnated catalyst precursor, wherein the molar ratio of elemental nickel introduced in the impregnation step f) to elemental nickel introduced in the co-kneading step b) is from 0.3 to 5mol/mol;

in step b), the porous alumina is additionally kneaded with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function or at least one alcohol function or at least one ester function or at least one amine function or at least one amide function, and

in step f), the dried catalyst precursor obtained in step d) or the calcined catalyst precursor obtained in step e) is additionally impregnated with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function or at least one alcohol function or at least one ester function or at least one amine function or at least one amide function.

2. The process according to claim 1, wherein the dried catalyst obtained in step g) is additionally subjected to a heat treatment step h) at a temperature of 250-1000 ℃ in the presence or absence of water to obtain a calcined catalyst.

3. The method according to claim 1 or 2, wherein the calcined porous alumina according to step a) is obtained by:

a3 A second precipitation step of precipitating the suspension obtained at the end of the heating step a 2) by adding to the suspension at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid, wherein at least one of the basic precursors or the acidic precursors comprises aluminum, the relative flow rates of the acidic precursor and the basic precursor being selected to obtain a reaction medium pH of 8.5 to 10.5, and the flow rates of the one or more acidic precursors and the basic precursor of aluminum being adjusted so as to obtain a progress rate of the second step of 87% -95%, the progress rate being defined as Al during the second precipitation step ₂ O ₃ The ratio of the alumina formed by the equivalent relative to the total amount of alumina formed at the end of step a 3) of the preparation process, said stepCarrying out the steps at a temperature of 40-90 ℃ for 2 to 50 minutes;

a5 A step of drying the alumina gel obtained in step a 4) to obtain a powder;

a6 A step of heat-treating the powder obtained at the end of step a 5) for 2-10 hours at 500-1000 ℃ in the presence or absence of an air stream containing up to 60% by volume of water to obtain calcined porous alumina.

4. The method according to claim 1 or 2, wherein the calcined porous alumina according to step a) is obtained by:

a3 ') a step of coprecipitating the suspension obtained at the end of step a 2') by adding to the suspension at least one basic precursor selected from sodium aluminate, potassium aluminate, ammonia, sodium hydroxide and potassium hydroxide and at least one acidic precursor selected from aluminum sulfate, aluminum chloride, aluminum nitrate, sulfuric acid, hydrochloric acid and nitric acid, at least one of the basic precursors or acidic precursors comprising aluminum, the relative flow rates of the acidic precursor and basic precursor being selected to obtain a reaction medium pH of 7 to 10, and the flow rates of the one or more acidic precursors and basic precursor containing aluminum being adjusted so as to obtain a final alumina concentration in the suspension of 10 to 38g/l,

a6 ') a step of heat-treating the powder obtained at the end of step a 5') at a temperature of 500-1000 ℃ in the presence or absence of an air stream containing up to 60% by volume of water for 2-10 hours to obtain calcined porous alumina.

5. The method according to claim 1, wherein said step f) comprises the sub-steps of:

f2 Impregnating the catalyst precursor obtained in step d) or step e) with at least one solution comprising at least one organic compound comprising at least one carboxylic acid function or at least one alcohol function or at least one ester function or at least one amide function or at least one amine function;

substep f 1) and substep f 2) are carried out in any order.

6. The method according to claim 1, characterized in that the organic compound comprises at least one carboxylic acid functional group selected from the group consisting of monocarboxylic acids, dicarboxylic acids, tricarboxylic acids or tetracarboxylic acids.

7. The method according to claim 1, characterized in that said organic compound comprising at least one alcohol function is selected from the group consisting of:

-an organic compound comprising only one alcohol function;

-an organic compound comprising two alcohol functions;

-glucose, mannose, fructose or derivatives thereof;

disaccharides or trisaccharides.

8. The process according to claim 7, wherein the organic compound comprising two alcohol functions is selected from diethylene glycol, triethylene glycol, tetraethylene glycol or a compound corresponding to formula H (OC ₂ H ₄ ) _n OH, wherein n is greater than 4 andan organic compound of polyethylene glycol having an average molar mass of less than 20 g/mol.

9. The method according to claim 1, characterized in that said organic compound comprising at least one ester function is selected from the group consisting of:

-a linear carboxylic acid ester or a cyclic carboxylic acid ester;

-cyclic or linear carbonates.

10. The process according to claim 9, characterized in that the cyclic carboxylic acid ester is an unsaturated cyclic carboxylic acid ester and the linear carbonate is a linear carbonate diester.

11. The method according to claim 1, characterized in that said organic compound comprising at least one ester function is selected from the group consisting of:

-an organic compound comprising at least two carboxylate functional groups;

-an organic compound comprising at least one carboxylate functionality and at least one second functionality selected from alcohols, ethers, ketones or aldehydes.

12. The method according to claim 1, characterized in that said organic compound comprising at least one amide function is selected from the group consisting of:

acyclic amides comprising one or two amide functions;

-cyclic amides.

13. The method according to claim 1, characterized in that said organic compound comprising at least one amide function is selected from the group consisting of:

-an organic compound comprising at least one amide function and a carboxylic acid function or an organic compound comprising at least one amide function and an alcohol function;

14. The method according to claim 1, wherein the organic compoundThe compound comprises at least one amine functional group corresponding to the empirical formula C _x N _y H _z Where x is 1 to 20, y=1 to x and z=2 to (2x+2).

15. A process for the selective hydrogenation of polyunsaturated compounds containing at least 2 carbon atoms per molecule, said polyunsaturated compounds being diolefins and/or acetylenic compounds and/or alkenylaromatic compounds, present in a hydrocarbon feedstock having a final boiling point of less than or equal to 300 ℃, in the presence of a catalyst obtained according to any one of claims 1 to 14, said process being carried out in the liquid phase at a temperature of 0 to 300 ℃, a pressure of 0.1 to 10MPa, a hydrogen/polyunsaturated compound molar ratio to be hydrogenated of 0.1 to 10 and for 0.1 to 200h when said process is carried out in the liquid phase ^-1 Is carried out at a hourly space velocity or, when the process is carried out in the gas phase, at a molar ratio of hydrogen to polyunsaturated compound to be hydrogenated of from 0.5 to 1000 and from 100 to 40,000 hours ^-1 Is carried out at a space-time rate of (3).

16. A process for hydrogenating at least one aromatic compound present in a hydrocarbon feedstock having a final boiling point of less than or equal to 650 ℃ in the presence of a catalyst obtained according to any of claims 1 to 14, said process being in the gas or liquid phase at a temperature of 30 to 350 ℃, a pressure of 0.1 to 20MPa, a hydrogen/aromatic compound molar ratio to be hydrogenated of 0.1 to 10 and of 0.05 to 50 h ^-1 Is carried out at a space-time velocity HSV.