WO2019115919A1

WO2019115919A1 - Molybdenum-based composition

Info

Publication number: WO2019115919A1
Application number: PCT/FR2018/053162
Authority: WO
Inventors: Chantal ROTILLON; Nicolas BARTHEL; Thomas Mathivet
Original assignee: Rhodia Operations
Priority date: 2017-12-13
Filing date: 2018-12-07
Publication date: 2019-06-20

Abstract

The present invention relates to a molybdenum-based composition and to the use thereof as a precursor of a molybdenum sulfide-based catalyst. The invention also relates to the method for producing said composition.

Description

Composition based on molybdenum

The present application claims the priority of the French patent application No. 1762098 filed on December 13, 2017, the content of which is incorporated in its entirety by reference. In case of inconsistency between the text of the present application and the text of the French patent application which affects the clarity of a term or expression, reference will be made to this application only.

Technical area

The present invention relates to a molybdenum-based composition and its use as a precursor of a molybdenum sulfide catalyst. The invention also relates to the process for preparing said composition.

Technical problem

The technical context is that of hydroconversion in the presence of catalysts based on molybdenum sulphide. Industrial processes for hydroconversion of heavy loads already exist. There may be mentioned the Exxon MRC process which operates between 420 ° C. and 450 ° C. under a pressure of between 10 and 15 MPa, or the Asahi Chemicals SOC process which operates at a higher temperature, 475-480 ° C., under higher pressure (20-22 MPa). The EST process developed by IΈNI which is a hydroconversion process of heavy charges in bubbling bed allows to achieve high conversions using a catalyst recycling. The catalyst that is used in the EST process is well dispersed molybdenum sulfide particles obtained in situ from an oil-soluble molybdenum compound. The oil-soluble compound is introduced into the hydroconversion reactor at the same time as the feedstock to be treated. The catalytic activity of the catalyst is maintained despite recycling. Molybdenum 2-ethylhexanoate is an oil-soluble compound known and used as a precursor in the preparation of a hydroconversion catalyst.

The precursor that is used must have a viscosity that is suitable for handling and easy introduction into the hydroconversion process. Of moreover, it is necessary that the precursor has a high molybdenum content.

The Applicant has developed a composition based on molybdenum that can be used as a precursor, which aims to solve this technical problem.

Prior art

WO 2008/141831 discloses a method of hydroconversion of a heavy load using a molybdenum catalyst. Molybdenum octoate or 2-ethylhexanoate is used as catalyst precursor. However, there is no information on the free acid content.

WO 2009/149923 discloses a heavy charge hydroconversion process using a molybdenum catalyst which is prepared from an oil soluble molybdenum compound. The compound described is molybdenum 2-ethyl hexanoate. However, there is no information on the free acid content.

WO 2013/098741 discloses a hydrotreatment process using a molybdenum-based catalyst prepared from an oil-soluble molybdenum compound which may be 2-ethyl hexanoate, naphthenate or molybdenum hexanoate. However, there is no information on the free acid content

US 2013/0248422 discloses a hydroconversion process of a heavy charge using a molybdenum salt which may be 10-undecenoate, dodecanoate, 3-cyclo-pentylpropionate, cyclohexanebutyrate, 4-heptylbenzoate, 5-phenylvalerate or 3,7-dimethyl-2,6-octadienoate. This document does not describe the particular carboxylates of the invention.

EP 0512778 describes a method of hydroconversion of a heavy charge using a molybdenum salt in combination with another salt of another metal, for example cobalt.

About the invention

The invention relates to a composition comprising (i) a molybdenum carboxylate selected from the group consisting of molybdenum 2-ethyl hexanoate, neodecanoate or 3,5,5-trimethylhexanoate and (ii) respectively the acid 2-ethylhexanoic acid, neodecanoic acid or 3,5,5-trimethylhexanoic acid, characterized in that it has a proportion of molybdenum weight greater than or equal to 13.0%, more particularly greater than or equal to 14.0%, even greater than or equal to 15.0%, and even greater than or equal to 16.0%. This composition can be used as a precursor of a molybdenum sulfide catalyst. The invention also relates to the use of said composition in a hydroconversion process of a heavy load.

Detailed description of the invention

The composition of the invention comprises, on the one hand, a molybdenum carboxylate selected from the group consisting of molybdenum 2-ethyl hexanoate, neodecanoate or 3,5,5-trimethylhexanoate (i).

The term "molybdenum carboxylate" refers to the product resulting from the reaction between a carboxylic acid and molybdic acid, ammonium dimolybdate or ammonium heptamolybdate. This reaction is preferably carried out hot, more particularly at a temperature of at least 180 ° C., more particularly between 180 ° C. and 250 ° C. Thus, 2-ethyl hexanoate molybdenum is the product prepared from the carboxylic acid of formula _(I).

Molybdenum neodecanoate means the product prepared from the acid or mixture of carboxylic acids of formula (II):

in which n and m represent integers for which n + m is 7. The formula (I) therefore comprises a total of 10 carbon atoms. An example of an acid corresponding to formula (II) is the compound of formula:

The acid or mixture of acids of formula (II) generally has an acid number according to ASTM D1980 of between 310 and 330 mg KOH / g, and even between 310 and 325 mg KOH / g or between 320 and 330 mg KOH / g. As examples of commercial acids according to formula (II), it will be possible to use the "Versatic Acid 10" brand product marketed by Hexion or the "Neo Decanoic Acid" brand product marketed by Exxon- Mobil.

Molybdenum 3,5,5-trimethylhexanoate refers to the product prepared from the carboxylic acid of formula (III):

In the composition, the molybdenum is coordinated with the carboxylate ligands. This makes it possible to solubilize the molybdenum in the composition.

On the other hand, the composition of the invention also comprises free carboxylic acid (corresponding to the carboxylate) (ii). The proportion by weight of the carboxylic acid may be less than or equal to 50.0%, more particularly less than or equal to 40.0%, or even less than or equal to 30.0%. The proportion by weight of carboxylic acid may be greater than or equal to 20.0%. This proportion can be determined by liquid chromatography (HPLC). This proportion is determined by weight of the free carboxylic acid relative to the total weight of the composition.

It should be noted that the neodecanoic and 3,5,5-trimethylhexanoic acids have the advantage of not being classified in the family of CMR substances (CMR = Carcinogenic-Mutagen-Reprotoxic) by the European authorities. The composition of the invention may have a proportion by weight of molybdenum greater than or equal to 13.0%, more particularly greater than or equal to 14.0%, even greater than or equal to 15.0%, or even greater than or equal to 16.0%. This proportion may be less than or equal to 25.0%, or even less than 20.0%. This proportion can also be between 13.0% and 20.0%, between 14.0% and 20.0%, between 15.0% and 20.0% or between 16.0% and 20.0% . This proportion is determined by weight of the molybdenum element relative to the total weight of the composition. The method described in the examples can be used to determine this proportion of molybdenum. This method is based on the calcination in air (500 ° C / 2 h) of the composition after filtration to remove any solid compounds present in the composition. Filtration makes it possible in particular to remove solid compounds based on molybdenum, such as, for example, the molybdenum-based starting compound. Thus, the proportion of molybdenum that is indicated is the proportion of the molybdenum of the carboxylate. Calcination makes it possible to eliminate all the organic compounds. The proportion by weight of molybdenum is then given by the formula:

% Mo = (a / m) x (M MO / M _MO O3) X 100

m: weight of the composition

a: weight of the residue after calcination in the air

M _MO : molar mass of molybdenum (95.94 g / mol)

M _MOO 3: molar mass of molybdenum oxide M0O3 (143.94 g / mol)

Furthermore, the composition may have a reduced dynamic viscosity, which allows it to be handled and pumped easily with pumping tools. In the present application, this dynamic viscosity is measured at a shear rate of 2 s ¹ . The composition may have a dynamic viscosity at 25 ° C. of less than or equal to 2000 cPs, more particularly less than or equal to 1700 cPs, or even less than or equal to 600 cPs.

The composition may also have a dynamic viscosity at 40 ° C. of less than or equal to 600 cPs, more particularly less than or equal to 300 cPs, or even less than or equal to 200 cPs.

The composition of the invention may have a level of hexane insolubles which is less than or equal to 2.0% by weight, or even less than or equal to 1.5% by weight. A low insoluble level is sought after because insolubles are likely to lead to deposits or fouling in the lines, as well as possible blockages of lines. In addition, the deposits can be transformed into molybdenum oxide, which is a toxic product. This level of insolubles may be less than or equal to 1.0%, more particularly less than or equal to 0.5%, or even less than or equal to 0.2%. This level of insolubles is determined by a mass balance performed after filtration of a mixture of the composition and hexane through a filter. The insoluble level measurement procedure described in the examples can be used. The level of insolubles is given in% by weight relative to the entire composition.

In the carboxylate, the molybdenum may be present at the oxidation state + VI.

The composition may more particularly comprise (i) molybdenum neodecanote and (ii) neodecanoic acid and have a proportion by weight of neodecanoic acid less than or equal to 50.0%, more particularly less than or equal to 40.0% or even less than or equal to 30.0%. Moreover, this particular composition can also present

^■ a dynamic viscosity at 25 ° C less than or equal to 2000 cPs. This viscosity may be greater than or equal to 1300 cPs; and or

^■ a dynamic viscosity at 40 ° C less than or equal to 600 cPs. This viscosity may be greater than or equal to 300 cPs.

The composition may more particularly comprise (i) molybdenum 3,5,5-trimethylhexanoate and (ii) 3,5,5-trimethylhexanoic acid and have a proportion by weight of lower 3,5,5-trimethylhexanoic acid. or equal to 40.0%, more particularly less than or equal to 30.0%. This particular composition can also present:

^■ a dynamic viscosity at 25 ° C less than or equal to 600 cPs. This viscosity may be greater than or equal to 80 cPs; and or

^■ a dynamic viscosity at 40 ° C less than or equal to 300 cPs. This viscosity may be greater than or equal to 30 cPs.

The composition according to the invention may be prepared by reacting molybdic acid, ammonium dimolybdate or ammonium heptamolybdate with the corresponding carboxylic acid (described above) in an initial molar ratio carboxylic acid / Mo between 2.5 and 4.2, more particularly between 2.9 and 4.1. This ratio may be more particularly close to 3.0, for example between 2.9 and 3.1. The reaction mixture is brought to a temperature of at least 180 ° C, more particularly between 180 ° C and 250 ° C. The temperature of the reaction mixture may be substantially equal to the boiling point of the carboxylic acid used. The water that forms during the reaction is eliminated. In the laboratory, one can for example use a Dean-Stark type of assembly.

The duration of the reaction making it possible to obtain the composition according to the invention varies as a function of the temperature of the reaction, the nature of the carboxylic acid used and the initial molar ratio carboxylic acid / Mo. This duration can be determined by following the conversion of the reaction using the measurement of the volume of water collected. This duration is generally at least 10 hours, or even at least 15 hours. At the end of the reaction step, it is then possible to separate the insolubles from the reaction mixture so as to recover the composition of the invention. For example, the reaction mixture can be filtered, for example by sintering.

The invention also relates to the composition obtainable by the process thus described.

About the use of the composition according to the invention

The composition of the invention can be used as a precursor to a molybdenum sulfide catalyst, which means that the molybdenum carboxylate is converted to molybdenum sulfide. The carboxylate sulphide conversion takes place in the presence of at least one sulphurizing agent and hydrogen. The transformation takes place at elevated temperature, typically between 250 ° C. and 500 ° C., preferably between 250 ° C. and 400 ° C. The hydrogen partial pressure is high, typically between 30 bars and 300 bars, preferably between 50 and 200 bars. A sulfurizing agent is a chemical molecule containing one or more sulfur atom (s) whose function is to convert an oxide into a sulphide. As a result of the conversion, the molybdenum sulphide may be present in whole or in part in the form of MoS ₂ or in the form of another sulphide than MoS ₂ . It is also possible that the sulphurization is not total, which means that, after sulphurization, the molybdenum sulphide is wholly or partly in the form of a molybdenum oxysulphide. The molybdenum sulfide catalyst can be used in a hydroconversion process, including a hydroconversion process of a heavy load. It may be a process suspended or bubbling bed. The term "hydroconversion" refers to all processes in which a hydrocarbon feedstock reacts with hydrogen. Among the hydroconversion processes, mention may be made of hydrotreatment which consists in reducing the content of certain impurities in a feed (N, S, O, metals). One can also mention hydrocracking which consists of converting a heavy load into a lighter load. The molecules of the heavy charge are broken down to reduce their molecular weight and the H / C index of the charge increases. The heavy load generally designates a hydrocarbon feedstock of which at least 80% by weight has a boiling point greater than or equal to 340 ° C. The heavy load can be, for example, a crude oil, a bitumen, a residue of atmospheric or vacuum distillation, a fraction of gas oil obtained under vacuum (VGO), a heavy oil, a distillate distillation residue, an oil shale or another load from biomass. The main function of the molybdenum sulphide catalyst is to activate the hydrogen and to promote the transfer of hydrogen from the gas phase to the charge to be treated. The molybdenum sulphide catalyst also has a function of removing impurities from the feedstock, in particular reduction of sulfur (hydrodesulfurization, HDS), reduction of metals, in particular Ni and V, (hydrodemetallation, HDM), reduction of the nitrogen (hydrodenitrogenation, HDN) or oxygen reduction (hydrodeoxygenation, HDO). It is thus possible to reduce respectively the concentration of impurities S, metals, N, O contained in the charge to be treated.

The sulphurising agent can be, for example, hydrogen sulphide (H ₂ S) or an organic compound which can release H ₂ S. For example, the sulphurising agent can be dimethyldisulphide (DMDS) which has a strong sulfur content and is safe to use (low volatility, low flammability and moderate toxicity). In the case of in situ sulfurization described below, the sulfur-containing organic compound which can release H ₂ S can be contained in the hydrocarbon feedstock to be treated itself.

The conversion of the molybdenum carboxylate to molybdenum sulphide can take place at any time during the process. It can take place before introducing the carboxylate into the hydroconversion reactor, it is called presulphuration or ex situ sulphurization. It can also operate within the hydroconversion reactor itself, it is called in situ sulfurization. The organic sulfur compound may already be present in the batch to be treated itself. It is also possible to add a sulphurizing agent (typically DMDS) to the hydrocarbon feedstock, since the sulphurizing agent releases H ₂ S at lower temperatures than the sulfur compounds already present in the feedstock to be treated.

Examples of processes that can use the carboxylate according to the invention are those described in applications WO 2006/06691 1, EP 2148912, WO 2008/141831 or WO 2008/151792.

Examples of molybdenum sulfide catalysts will now be described more precisely. According to a first example, the composition of the invention makes it possible to prepare a molybdenum sulphide-based catalyst in the form of nanosilicon of MoS 2, especially in the form of sheets. The length of a sheet may preferably be less than or equal to 20 nm, even more preferably less than 10 nm. MO2 can be in the form of a stack of less than 10 sheets, preferably less than 5 sheets. The nanodispersed form of M0S2 makes it possible to obtain a high catalytic activity. The MO.sub.2 nanoparticles may be suspended in the hydroconversion reactor or may be dispersed on the surface of carbonaceous particles, such as, for example, coke particles present in the hydroconversion reactor. In the in situ preparation, the composition of the invention and a feedstock to be treated, in particular a heavy feedstock, are introduced into a hydroconversion reactor, the conversion of the carboxylate into molybdenum sulphide taking place in the presence of at least one agent. sulfurant and hydrogen.

Molybdenum sulfide may be used as the sole catalyst or combined with one or more other catalyst (s). Thus, according to a second example, the composition according to the invention makes it possible to prepare molybdenum sulphide which acts in combination with a cracking catalyst which is in the form of micro- or nanometric particles. The micrometric particles of the cracking catalyst may have a size of less than 10 μm, or even less than 5 μm, or even less than 1 μm. The nanoscale particles of the cracking catalyst may have a size less than 10 nm, or even less than 5 nm, or even less than 1 nm. The size of the particles can be the median value d50 determined by transmission electron microscopy (TEM): by observing several images, it is possible to obtain a number distribution of the diameters of the particles. The distribution therefore represents the number of particles distributed by classes, the class width being adapted to the size of the particles and taking into account the maximum size. The number of classes is generally between 10 and 20. The number of particles in each class is the basic data to represent the (cumulative) number distribution. The diameter to be taken into account is that of the minimum circle making it possible to circumscribe the entirety of the image of the particle as it is visible on a MET plate. The term "minimum circle" has the meaning given to it in mathematics and represents the circle of minimum diameter to contain a set of points of a plane. Only particles with at least half of the perimeter are defined. ImageJ software can be used to do more simple processing; this open access software was originally developed by the NIH American Institute and is available at http://rsb.info.nih.aov/ii/download.html.

The combination of the two catalysts, MoS ₂ and cracking catalyst, can be used to improve the conversion of heavy loads, especially in a bed reactor suspended or bubbling bed. The cracking catalyst serves to reduce the molecular weight of the molecules of the charge to be treated. The cracking catalyst generally consists of a material having an acid function of bronsted or Lewis. By way of examples, it may be an amorphous alumino-silicate, in particular a silica-alumina, a crystallized aluminosilicate, in particular a zeolite, for example of the HY, Y or beta type. The cracking catalyst may also be an ordered mesoporous, in particular of the MCM type, for example MCM-22, or an acidified alumina, for example by phosphorus. For this combination, the molybdenum sulphide can again be in the form of MoS ₂ nanoparticles as described above. The nanoparticles of MoS ₂ can be suspended in the hydroconversion reactor and / or dispersed on the surface of carbonaceous particles, for example coke particles, present in the hydroconversion reactor and / or dispersed on the surface of the particles. cracking catalyst. In situ preparation is introduced into a hydroconversion reactor the composition of the invention, the cracking catalyst, a feedstock to be treated, especially a heavy feedstock, the conversion of the carboxylate to molybdenum sulphide taking place in the presence of at least one sulphurizing agent and hydrogen .

In the context of the present invention, it is not excluded that the molybdenum in molybdenum sulphide is combined with one or more other metallic element (s) chosen from the group formed by nickel, cobalt and nickel. tungsten. This combination improves the activity of molybdenum. Such a combination can be achieved by combining the composition of the invention with another precursor of the element (s) metal (s) before introduction into the hydroconversion reactor.

According to a third example, the composition of the invention makes it possible to prepare a hydrotreatment catalyst composed of particles of a mineral material on which is partially or completely deposited a layer of molybdenum sulphide. The inorganic material may be an alumina, in particular a crystallographic phase, pure or doped, an amorphous or crystalline aluminosilicate of zeolite type, especially a zeolite beta. The mineral material is preferably in the form of beads, granules or extrusions, the diameter and / or the characteristic length are generally of the order of 0.5 to 6 mm. The molybdenum sulfide layer preferably has a thickness of from 0.001 μm to 1.0 μm, or even 0.01 μm to 0.1 μm. The catalyst can be prepared in situ by introducing into a fixed-bed reactor containing the particles of the inorganic material, the molybdenum carboxylate, the feedstock to be treated, the conversion of the carboxylate to molybdenum sulphide taking place in the presence of at least one sulfurizing agent and hydrogen. The operation for obtaining the layer of molybdenum sulphide requires to operate in two steps: in a 1 ^st step, the temperature within the reactor is sufficiently low to prevent the formation of molybdenum sulfide, which allows the carboxylate to be adsorbed to the surface of inorganic material without it decomposes and in a 2 ^nd step, the temperature is increased to promote the conversion of the carboxylate molybdenum sulfide.

The composition of the invention can be used in any hydroconversion process of a heavy fraction. Generally, the hydroconversion is carried out at elevated temperature, typically between 320 ° C. and 500 ° C. preferably between 350 ° C and 450 ° C. The hydrogen partial pressure is high, typically between 30 bars and 300 bars, preferably between 50 bars and 200 bars.

The molybdenum content in the feedstock to be treated is to be adapted according to the desired performances, the operating conditions and in particular according to the nature of the feedstock to be treated. By way of indication, the content by weight of molybdenum may be between 10 ppm and 30,000 ppm, preferably between 100 ppm and 5000 ppm, this content being expressed in ppm of molybdenum metal relative to the weight of the feedstock. treat present in the reactor.

Examples

Products used

Molybdic acid marketed by Sigma Aldrich or Alfa Aesar was used. This product is in the form of a white powder having a loose bulk density measured in a test tube of 1.45 g / cm ³ . The purity is 85.3% by weight of MoO ₃ . Mo is at the oxidation state of + VI.

Ammonium heptamolybdate of formula (NH ₄ ) ₆ Mo ₇ q ₂ ₄ 4H ₂ O marketed by Climax Molybdenum has also been used. This product is in the form of a white powder having a loose bulk density measured in a test tube of 1.7 g / cm ³ . The purity is 81.5% by weight in M0O ₃ . Mo is at the oxidation state of + VI.

Dynamic Viscosities

Dynamic viscosities were measured using a Kinexus rheometer under the following conditions:

- plane cone geometry of 40 mm and 4 °;

- crushing 0.15 mm

Viscosities were measured at several temperatures (0 ° C, 25 ° C and 40 ° C) at a shear rate of 2 s ¹ .

Insoluble levels in hexane

The level of insolubles is determined by the following method:

precisely about 1.0 g of the composition based on Mo is weighed;

hexane (200 ml hexane / g of composition) is added; the mixture is heated at 50 ° C. with magnetic stirring for at least 10 minutes;

a PTFE filter membrane (0.45 μm pores) is weighed;

the mixture is filtered through the filter membrane disposed in a millipore system and the retained residue is rinsed with a little hexane to remove the carboxylate residues;

the membrane is allowed to dry in an oven at 100 ° C .;

the amount of insoluble residues and the level of insolubles in% (weight of insoluble residues / weight of the composition x 100) are then determined by weighing.

% free acid

The% of free carboxylic acid is determined by HPLC. chromatoqraphic conditions for 2-ethylhexanoate and 3,5,5-trimethyl hexanoate (isononanoate)

Column: Zorbax Eclipse XDB C8 150 x 4.6 mm 5 pm No. USRK06851 1

eluent: acidified water (H ₂ SO ₄ 0.005 M) 50 / acetonitrile 50 followed by a gradient of 100% acetonitrile (after 8 min)

- injection: 50 pL

- detection: UV 210 nm

- flow rate: 1 mL / min chromatoqraphic conditions for neodecanoate

Column: Zorbax Eclipse XDB C8 150 x 4.6 mm 5 pm No. USRK06851 1

eluent: acidified water (H ₂ S0 ₄ 0.005 M) 40 / acetonitrile 60 followed by a gradient of 100% acetonitrile (after 8 min)

- injection: 50 pL

- detection: UV 210 nm

- flow rate: 1 mL / min

Proportion of molybdenum in the composition of the invention (% Mo)

The method is based on the calcination in air (500 ° C / 2 h) of the composition after filtration to remove any solid compounds present in the composition. Filtration makes it possible in particular to remove solid compounds based on molybdenum, such as, for example, the molybdenum-based starting compound. Calcination makes it possible to eliminate all the organic compounds.

% Mo = (a / m) x (M MO / MOCOC) X 100 m: weight of the composition

a: weight of the residue after calcination

molar mass of molybdenum (95.94 g / mol)

M _MO 03: molar mass of molybdenum oxide M0O3 (143.94 g / mol)

Specifically, the following method was used:

approximately 3 to 4 ml of the composition is filtered using a PTFE filter tip (0.45 μm)

the weight of the filtered product is determined (m)

the product is evaporated to dryness on a hot plate while gently raising the temperature of the plate

the quantity of molybdenum oxide (a) is weighed

Example 1 Composition Based on Molybdenum 2-Ethylhexanoate

77.4 g of 2-ethylhexanoic acid, 31.3 g of ammonium heptamolybdate (NH ₄ ) ₆ Mq 7q 2 ₄ × 4H ₂ O are mixed in a three-necked flask of 500 ml, equipped with a thermometer and with a Dean-Stark equipped with a reflux condenser. The flask is then placed under magnetic stirring and heated using an electric balloon heater. The mixture is heated at 200 ° C under nitrogen flushing for 31 h 15 min. After filtration, the insolubles are separated off and a solution containing 19.2% by weight of molybdenum is obtained.

Example 2 Composition Based on Molybdenum 2-Ethylhexanoate

The conditions of Example 1 are repeated except that the stoichiometric acid / Mo ratio is 4.0 and the reaction time is 27 h.

Table I

Example 3 Composition Based on Molybdenum Neodecanoate

91.6 g of neodecanoic acid, 30.0 g of molybdic acid (content of M0O3> 85%) are mixed in a three-necked flask of 500 ml, equipped with a thermometer, and a Dean-Stark equipped with a reflux condenser. The ball is then placed under magnetic stirring and the mixture is heated using an electric balloon heater. The mixture is heated at 237 ° C under a nitrogen sweep for 26 hours. After filtration of the reaction mixture, the insolubles are separated and a solution of molybdenum neodecanoate containing 16.5% by weight of molybdenum is obtained.

Example 4 Composition Based on Molybdenum Neodecanoate

The conditions of Example 3 are repeated except that the stoichiometric acid / Mo ratio is 4.0 and the reaction time is 29 h 40 min.

Table II

Example 5 Example with 3.5.5-Trimethylhexanoate

84.2 g of 3,5,5-trimethylhexanoic acid (purity> 99% by weight), 31.3 g of ammonium heptamolybdate (NH ₄ ) ₆ Mo ₇ q 2 ₄ , 4H ₂ O are mixed in a 500 ml three-neck flask equipped with a thermometer and a Dean-Stark equipped with a reflux condenser. The flask is then placed under magnetic stirring and heated using an electric balloon heater. The mixture is heated at a temperature between 220 ° C and 226 ° C under nitrogen flushing for 17 h. The insolubles are separated off and a solution is obtained, the Mo content of which is estimated at 17% by weight of molybdenum.

Example 6 Example with 3,5,5-Trimethylhexanoate

12.3 g of 3,5,5-trimethylhexanoic acid (purity> 99% by weight), 30.0 g of molybdic acid (content of M0O3> 85%) are mixed in a three-necked flask of 500 ml, equipped with a thermometer and a Dean-Stark equipped with a reflux condenser. The flask is then placed under magnetic stirring and heated using an electric balloon heater. The mixture is heated at 226 ° C under a nitrogen sweep for 15h30. The insolubles are separated and a solution is obtained, the Mo content of which is estimated at 13.1% by weight of molybdenum. Table III

3,5,5-Trimethylhexanoic acid has the advantage of leading to little insoluble. In addition, the reaction with this acid is faster than for the other acids tested. Finally, the level of insolubles is very low (<0.1%).

Example 7 Molybdenum Nonanoate

15.6 g of nonanoic acid (purity> 97% by weight), 30.0 g of molybdic acid (content of M0O3> 85%) are mixed in a three-necked flask of 500 ml, equipped with a thermometer, and a Dean-Stark equipped with a reflux condenser. The flask is then placed under magnetic stirring and heated using an electric balloon heater. The mixture is heated at 237 ° C under an inert atmosphere under nitrogen for 21 h. The insolubles are separated off and a solution is obtained, the Mo content of which is estimated at 12.6% by weight of molybdenum.

The viscosity of this composition is higher than for the compositions of the preceding examples either at 25 ° C or at 40 ° C.

Example 8: Molybdenum iso-octadecanoate

206.8 g of isooctadecanoic acid (purity> 97.5% by weight), 30.0 g of molybdic acid (content of M0O3> 85%) are mixed in a three-necked flask of 500 ml, provided with a thermometer, and a Dean-Stark equipped with a reflux condenser. The flask is then placed under magnetic stirring and heated using an electric balloon heater. The mixture is heated at 200 ° C under an inert atmosphere under nitrogen for 7.5 h. After filtration, the insolubles are separated off and a solution containing 1.4% by weight of molybdenum is obtained.

The Mo content in this composition is lower than for the compositions of the preceding examples. In addition, the product is much more viscous.

Claims

A composition comprising (i) a molybdenum carboxylate selected from the group consisting of molybdenum 2-ethylhexanoate, neodecanoate or 3,5,5-trimethylhexanoate and (ii) respectively 2-ethylhexanoic acid , neodecanoic acid or 3,5,5-trimethylhexanoic acid, characterized in that it has a proportion by weight of molybdenum greater than or equal to 13.0%, more particularly greater than or equal to 14.0%, even greater than or equal to 15.0%, or even greater than or equal to 16.0%.

2. Composition comprising (i) the product resulting from the reaction between a carboxylic acid and molybdic acid, ammonium dimolybdate or ammonium heptamolybdate and (ii) the corresponding free carboxylic acid, characterized in that it has a proportion by weight of molybdenum greater than or equal to 13.0%, more particularly greater than or equal to 14.0%, even greater than or equal to 15.0%, and even greater than or equal to 16.0%.

3. Composition according to one of the preceding claims characterized in that the proportion by weight of the carboxylic acid may be less than or equal to 50.0%, more particularly less than or equal to 40.0% or 30.0%. %.

4. Composition according to one of the preceding claims wherein the dynamic viscosity at 25 ° C is less than or equal to 2000 cPs, more particularly less than or equal to 1700 cPs, or even less than or equal to 600 cPs.

5. Composition according to one of the preceding claims wherein the dynamic viscosity at 40 ° C is less than or equal to 600 cPs, more particularly less than or equal to 300 cPs, or even less than or equal to 200 cPs.

6. Composition according to one of the preceding claims having a level of insoluble in hexane which is less than or equal to 2.0% by weight, or even less than or equal to 1, 5% by weight, or even less than or equal to at 1, 0%, more particularly less than or equal to 0.5%, or even less than or equal to 0.2%.

7. Composition according to one of the preceding claims wherein the molybdenum may be present at the oxidation state + VI.

8. Composition according to one of the preceding claims comprising (i) molybdenum neodecanote and (ii) neodecanoic acid and having a proportion by weight of neodecanoic acid less than or equal to 50.0%, more particularly less than or equal to 40.0%, or even less than or equal to 30.0%.

9. The composition of claim 8 having:

^■ a dynamic viscosity at 25 ° C less than or equal to 2000 cPs; and or

^■ a dynamic viscosity at 40 ° C less than or equal to 600 cPs.

10. Composition according to one of claims 1 to 7 comprising (i) molybdenum 3,5,5-trimethylhexanoate and (ii) 3,5,5-trimethylhexanoic acid and having a proportion by weight of acid 3 , 5,5-trimethylhexanoic less than or equal to 40.0%, more particularly less than or equal to 30.0%.

1. The composition of claim 10 having

^■ a dynamic viscosity at 25 ° C less than or equal to 600 cPs; and or

^■ a dynamic viscosity at 40 ° C less than or equal to 300 cPs.

12. Composition according to one of the preceding claims wherein the proportion by weight of carboxylic acid is greater than or equal to 20.0%.

13. Composition according to one of the preceding claims wherein the proportion by weight of molybdenum is between 13.0% and 20.0%, between 14.0% and 20.0%, between 15.0% and 20, 0% or between 16.0% and 20.0%.

14. Process for the preparation of a composition according to one of claims 1 to 13 of reacting molybdic acid, ammonium dimolybdate or ammonium heptamolybdate with the corresponding carboxylic acid (described above) in an initial molar ratio carboxylic acid / Mo of between 2.5 and 4.2, more particularly between 2.9 and 4.1.

15. The process of claim 14 wherein the insolubles are separated from the reaction mixture.

16. The method of claim 14 or 15 wherein the reaction mixture is heated to a temperature of at least 180 ° C, more preferably between 180 ° C and 250 ° C.

17. Method according to one of claims 14 to 16 wherein the duration of the reaction is at least 10 hours, or even at least 15 hours.

18. Use of the composition according to one of claims 1 to 14 as a precursor of a molybdenum sulphide catalyst.

19. A process for preparing a molybdenum sulphide catalyst comprising converting the composition according to one of claims 1 to 14 into molybdenum sulphide, the transformation being carried out in the presence of at least one sulphurizing agent and hydrogen.

20. The method of claim 19 characterized in that the transformation takes place within a hydroconversion reactor.