Method for preparing at least one aromatic compound capable of storing and / or transporting dihydrogen

Abstract

The present invention relates to a method for preparing at least one compound of formula (I), preferably at least benzyltoluene (BT) and / or at least dibenzyltoluene (DBT) and / or one of the geometric isomers thereof, capable of storing and / or transporting dihydrogen.

Description

[0001] DESCRIPTION

[0002] TITLE: Process for preparing at least one aromatic compound suitable for storing and / or transporting dihydrogen

[0003] The present invention relates to a process for preparing at least one aromatic compound of formula (I), preferably at least benzyltoluene (BT) and / or at least dibenzyltoluene (DBT) and / or at least one of their geometric isomers, preferably suitable for storing and transporting dihydrogen.

[0004] Hydrogen currently represents an attractive alternative to fossil fuels, natural gas, and electricity. However, the storage and transport of this energy source remains a major challenge for its rapid and accessible development.

[0005] Several approaches have been studied to more easily store and transport this highly volatile and highly explosive gas, including high-pressure storage, cryogenic storage, and storage of gaseous hydrogen adsorbed or absorbed by a solid material.

[0006] Such approaches primarily present the major disadvantage of involving significant operational and / or energy costs. Indeed, storing hydrogen in its gaseous state under high pressure requires tanks capable of withstanding high pressures, ranging from 350 to 750 bar, or even higher, which necessitates the use of expensive composite materials. Cryogenic storage of hydrogen in its liquid state, on the other hand, requires cooling the hydrogen to a temperature below its boiling point of -253°C, which represents a considerable energy cost as well as the implementation of highly efficient cooling systems.Finally, the disadvantages of storing gaseous hydrogen in a solid material lie mainly in absorption or adsorption performance that is still too often low, in limited rates of hydrogen release under optimal pressures and temperatures, and in the instability of solid storage materials.

[0007] To overcome these drawbacks, hydrogen storage in a liquid medium has been favored. In particular, technology based on liquid organic hydrogen carriers (LOHC) is a promising and particularly attractive technology for long-distance transport, at costs entirely compatible with large-scale development.

[0008] The principle of this LOHC technology consists of fixing hydrogen onto a support molecule, which is preferably and most often liquid at room temperature, in a catalytic hydrogenation step, then releasing the fixed hydrogen, preferably near the point of consumption, in a catalytic dehydrogenation step.

[0009] Among the LOHC molecules studied today, aromatic liquids with two or three aromatic rings, such as benzyltoluene (BT) and / or dibenzyltoluene (DBT), represent molecules particularly well suited for long-term storage and long-distance transport of large quantities of hydrogen.

[0010] Indeed, organic LOHC liquids of the benzyltoluene (BT) and / or dibenzyltoluene (DBT) type have an advantageous physicochemical profile, notably a high flash point, a high boiling point, and thermal stability. Thus, such organic LOHC liquids can be easily handled, whether in their saturated or unsaturated form, over a wide temperature range, from -30 to 300°C, and are compatible with oil and petrochemical infrastructure.

[0011] The synthesis processes of benzyltoluene (BT) and / or dibenzyltoluene (DBT) are generally carried out in the presence of catalysts, for example zeolites or ferric chloride (EeCL), and most often include an alkylation reaction between benzyl chloride and toluene, alternatively between benzyl alcohol and toluene, or a reaction between diphenylmethane and toluene.

[0012] The operating conditions, for example the nature of the catalysts used, the temperature and / or the number of moles of toluene, make it possible to influence the kinetics of these synthesis processes and to favor the formation of benzyltoluene (BT), dibenzyltoluene (DBT) or mixtures of benzyltoluene (BT) and dibenzyltoluene (DBT).

[0013] Similarly, the operating conditions can also influence the quantities of ortho-, para-, or meta- isomers of benzyltoluene (BT) and dibenzyltoluene (DBT) formed during these synthetic processes. In all cases, such synthetic processes lead to mixtures of benzyltoluene (BT) and / or dibenzyltoluene (DBT) isomers.

[0014] Furthermore, the processes for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) usually result in a large volume consumption of chlorine (Cb) regardless of the starting reagent used (benzyl chloride, benzyl alcohol or diphenylmethane).

[0015] Indeed, benzyl chloride is generally produced industrially by radical activation between toluene and chlorine (CE), either through the addition of free radicals (AIBN, benzoyl peroxide, etc.) or through ultraviolet radiation, and leads to the formation of hydrochloric acid (HCl). Benzyl alcohol, on the other hand, is obtained by hydrolysis of benzyl chloride in the presence of basic saponifying agents to neutralize the gaseous hydrochloric acid (HCl) formed, while diphenylmethane is obtained by the reaction of benzyl chloride with benzene.

[0016] Thus, regardless of the synthetic route used, the processes for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) involve using benzyl chloride, as a synthetic intermediate or starting reagent, which is obtained from chlorine (Cl2).

[0017] Global production of benzyltoluene (BT) / dibenzyltoluene (DBT) is currently estimated at around 50 kilotons per year. However, to illustrate, the production of one tonne of benzyltoluene (BT) / dibenzyltoluene (DBT) requires quantities of chlorine (Cl2) ranging from 0.4 to 0.8 tonnes to carry out the previously described synthesis processes.

[0018] In addition, the processes for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) lead to the production of significant quantities of hydrochloric acid in gaseous form (HCl).

[0019] Indeed, as previously mentioned, the reaction producing one mole of benzyl chloride leads to the formation of one mole of gaseous hydrochloric acid (HCl). Similarly, the hydrolysis of benzyl chloride to produce one mole of benzyl alcohol also leads to the formation of one mole of gaseous hydrochloric acid (HCl). Finally, the alkylation reaction between benzyl chloride and toluene leads to the formation of gaseous hydrochloric acid (HCl).

[0020] On the other hand, the processes for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) are also responsible for the production of significant quantities of sodium hydroxide (NaOH).

[0021] Indeed, chlorine (Cl₂), used to industrially produce benzyl chloride, is commonly obtained by direct current electrolysis of aqueous sodium chloride (NaCl) solutions. Such electrolysis results in the co-production of sodium hydroxide, hydrogen, and possibly sodium hypochlorite (bleach) per ton of chlorine produced. Thus, for example, the production of one ton of chlorine, depending on the electrolysis process used, particularly the amount of electricity, generally produces between 1.05 and 1.12 tons of sodium hydroxide and between 300 and 350 Nm³ of hydrogen. 3 of hydrogen.

[0022] In view of the above, at present, the processes for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) require a considerable volume consumption of chlorine (Cb), generate a significant production of hydrochloric acid in gaseous form (HCl), which needs to be treated, and have a significant impact on the production of sodium hydroxide (NaOH).

[0023] In addition, such volume requirements for chlorine (Cl2) as well as the production of hydrochloric acid in gaseous form (HCl) and soda (NaOH), caused by the synthesis processes as described above, are expected to increase given the growing demand for hydrogen which will require in the coming decades the production of increasingly large volumes of benzyltoluene (BT) and / or dibenzyltoluene (DBT), estimated at between 100 and 1000 kilotons per year.

[0024] Finally, such disadvantages are also encountered during the preparation of other LOHC molecules having at least one aromatic ring in their structure, for example and without limitation phenylxylylethane (PXE), phenylethylenephenylethane (PEPE), diphenylethane or xylyl xylene, and obtained from a synthetic process comprising at least one halogenation chemical reaction between at least one compound having at least one aromatic ring substituted by at least one alkyl group and chlorine (Cl2).

[0025] Indeed, in the same way as for the preparation of benzyltoluene (BT) and / or dibenzyltoluene (DBT), such synthesis processes require a significant input of chlorine (Cl2), generally from an electrolysis of aqueous solutions of sodium chloride (NaCl), and produce significant quantities of sodium hydroxide and hydrochloric acid.

[0026] Thus, one of the objectives of the present invention is to implement a process for preparing at least one aromatic compound suitable for storing and transporting hydrogen, capable of overcoming the previously mentioned drawbacks, i.e., of significantly reducing the consumption of chlorine (Cb), resulting from the electrolysis of aqueous solutions of sodium chloride (NaCl), and of reducing the volumes of soda and hydrochloric acid generated during such a synthesis process.

[0027] In particular, one of the aims of the present invention is to propose a process for the preparation of benzyltoluene (BT) and / or dibenzyltoluene (DBT) which does not have the disadvantages mentioned above, i.e. in which the volume consumption of chlorine (CE), from an electrolysis of aqueous solutions of sodium chloride (NaCl), and the volume production of sodium hydroxide (NaOH) and hydrochloric acid (HCl) are significantly reduced, in particular compared to the processes classically implemented in the prior art.

[0028] The present invention therefore relates in particular to a method for preparing at least one compound of formula (I):

[0029] [Ch

[0030] Formula (I) in which:

[0031] - ni and m, whether identical or different, are equal to 0 or 1,

[0032] - A and B, identical or different, represent independently of each other, an aromatic ring possibly partially dehydrogenated, and possibly substituted by one or more hydrocarbon radicals, saturated or partially or totally unsaturated, comprising from 1 to 20 carbon atoms, preferably from 1 to 18 carbon atoms, preferably still from 1 to 12 carbon atoms, better from 1 to 10 carbon atoms, better still from 1 to 6 carbon atoms, typically from 1 to 3 carbon atoms,

[0033] - X represents a spacer group chosen from the divalent radical -(CRR')m- and the divalent radical >C=CRR', - R and R', identical or different, are chosen independently of each other, from hydrogen and a hydrocarbon radical, saturated or partially or totally unsaturated, comprising from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms,

[0034] - m represents an integer between 1 and 4 inclusive, said process comprising: i) at least one chlorination step (a) of at least one alkylated aromatic compound of the following formula (II):

[0035] A-(Ri)0(II)

[0036] Formula (II) wherein A represents an aromatic ring, optionally partially dehydrogenated, Ri represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical comprising from 1 to 20 carbon atoms, and o is an integer from 1 to 5, preferably equal to 1 or 2, said chlorination step (a) leading at least to the formation of hydrochloric acid (HCl) and at least one chloride of the alkylated aromatic compound of formula (II), ii) at least one coupling reaction step (b) between at least the chloride of the alkylated aromatic compound of formula (II), obtained at the conclusion of said at least chlorination step (a), and at least one aromatic compound of the following formula (III):

[0037] B-(R2) P (III)

[0038] Formula (III) wherein B represents an aromatic ring, optionally partially dehydrogenated, R2 represents a hydrogen atom or a saturated, or partially or totally unsaturated, hydrocarbon radical comprising from 1 to 20 carbon atoms, p is an integer from 1 to 5, preferably equal to 1 or 2, said coupling reaction step (b) leading at least to the formation of hydrochloric acid (HCl) and at least one aromatic compound of formula (I), iii) at least one recovery step (c) of the hydrochloric acid (HCl) formed at the end of at least step(s) (a) and / or (b), i) at least one conversion step (d) of hydrochloric acid (HCl) to chlorine (Cb), ii) at least one transfer step (e) of chlorine (Cb), from said at least conversion step (d), to said at least chlorination step (a), iii) optionally at a step of adding (e') chlorine (Cl2),capable of being produced by at least one electrolysis process of at least one aqueous solution of sodium chloride (NaCl) or by any other synthesis process, at said at least chlorination step (a).

[0039] The process according to the invention thus makes it possible to efficiently prepare at least one compound of formula (I), suitable for storing and transporting hydrogen, while considerably reducing the volumes of chlorine (Cl2) from at least one process of electrolysis of aqueous solutions of sodium chloride (NaCl) as well as the quantities of sodium hydroxide (NaOH) and hydrochloric acid (HCl) generated.

[0040] Advantageously, the process according to the invention has the advantage of regenerating large volumes of chlorine (Cl2) during its implementation, which leads to a significant reduction in the consumption of volumes of chlorine (Cl2) from at least one process of electrolysis of aqueous solutions of sodium chloride (NaCl) necessary for the preparation of the aromatic compound LOHC, all this without degrading the yield and / or the degree of purity.

[0041] In particular, the process according to the invention makes it possible to regenerate large volumes of chlorine (Cl2) from the conversion of hydrochloric acid (HCl) produced in said at least step (a) and / or (b).

[0042] In other words, the process according to the invention makes it possible to reduce the input of volumes of "fresh" chlorine (Cl2), i.e. from the implementation of one or more processes of electrolysis of aqueous solutions of sodium chloride (NaCl), compared to processes classically described in the prior art.

[0043] In other words, the process according to the invention makes it possible to increase the amount of chlorine (Cl2) regenerated compared to the amount of chlorine (Cl2) obtained from at least one electrolysis process of aqueous sodium chloride (NaCl) solutions. Advantageously, the amount of chlorine (Cb) regenerated during the implementation of the process according to the invention, compared to the amount of chlorine (Cb) required for the production of the aromatic compound LOHC, is at least 80%, preferably at least 90%, and more preferably at least 95%.

[0044] The process according to the invention thus makes it possible to preserve natural resources, such as sodium chloride salts, and to maintain economic balances by limiting the production of hydrochloric acid and soda and potentially sodium hypochlorite (bleach).

[0045] The quantity of chlorine (Cl2) transferred during step (e) to the chlorination step (a) can advantageously be supplemented with new quantities of chlorine (Cl) from at least one process of electrolysis of aqueous solutions of sodium chloride (NaCl) as well as from any other type of synthesis process.

[0046] Thus the quantity of chlorine (CI2) regenerated can be supplemented with "fresh" chlorine to advantageously compensate for losses related to secondary reactions that may occur during the implementation of step (a) and / or (b).

[0047] The process according to the invention thus makes it possible to prepare large quantities of at least one aromatic compound of formula (I) with a low demand for "fresh" chlorine, i.e. not regenerated during the process, and while preserving large volumes of salts, in particular aqueous solutions of sodium chloride.

[0048] Furthermore, the process according to the invention leads to a reduction in the quantities produced of sodium hydroxide (NaOH) and hydrochloric acid (HCl).

[0049] Advantageously, the process according to the invention leads to a reduction in the quantities of hydrochloric acid produced at at least one of the steps (a) and

[0050] (b).

[0051] Advantageously, the process according to the invention ensures better valorization of by-products from at least one of the steps (a), (b),

[0052] (c), (d) and / or (e).

[0053] Indeed, the by-product(s) from at least one of steps (a), (b), (c), (d), and / or (e) is or are efficiently transferred to at least one of the steps of the process. The process according to the invention thus makes it possible to prepare at least one compound of formula (I), capable of meeting the requirements for the storage, transport, and release of hydrogen under optimal industrial and economic conditions.

[0054] The compound(s) of formula (I) can / are advantageously be used as LOHC compound(s).

[0055] In the LOHC application, the hydrogen transport formulations whose use is the subject of the present invention are particularly well suited because of their stability which allows reuse in a large number of hydrogenation / dehydrogenation cycles for the transport and handling of hydrogen from the steam cracking of petroleum products, waste hydrogen from chemical reactions such as salt electrolysis or hydrogen from water electrolysis.

[0056] The compound of formula (I) can also be used as a heat transfer fluid, dielectric fluid, solvent for purifying gaseous effluents containing aromatic impurities, plasticizers and process solvents.

[0057] The invention also relates to a method for preparing at least one compound of formula (IV) and / or at least one of its geometric isomers:

[0058] [Chem 2]

[0059] Formula (IV) in which: ni is an integer equal to 0 or 1;said process comprising: i) at least one chlorination step (a) of toluene leading to at least the formation of hydrochloric acid (HCl) and benzyl chloride, ii) at least one coupling reaction step (b) between the benzyl chloride from at least the chlorination step (a) and toluene, leading to at least the formation of at least one compound of formula (I), iii) at least one recovery step (c) of the hydrochloric acid formed in at least step(s) (a) and / or (b), iv) at least one conversion step (d) of hydrochloric acid to chlorine (Cb), v) at least one transfer step (e) of the chlorine (Cb), from at least the conversion step (d), to at least said chlorination step (a), vi) optionally at least one addition step (e') of chlorine (Cl2), which may be derived of at least one process of electrolysis of at least one aqueous solution of sodium chloride (NaCl) or of any other synthesis process, in step (a).;

[0060] The compound(s) of formula (I) is / are obtained, in particular, from products of renewable origin. In other words, the compounds of formulas (II) and (III) are obtained, in particular, from products of renewable origin.

[0061] The carbon in a renewable product comes from plant photosynthesis and therefore from atmospheric CO2. The term "biocarbon" indicates that the carbon is of renewable origin and comes from a biomaterial, as described below. Biocarbon content and biomaterial content are terms that refer to the same value.

[0062] A renewable material, also called a biomaterial, is an organic material in which the carbon comes from CO2 recently fixed (on a human timescale) from the atmosphere through photosynthesis. On land, this CO2 is captured or fixed by plants. In the sea, CO2 is captured or fixed by bacteria or plankton carrying out photosynthesis.

[0063] A biomaterial (100% naturally sourced carbon) has a 14C / 12C isotopic ratio greater than 10⁻¹², typically on the order of 1.2 x 10⁻¹² 12whereas a fossil material has a zero ratio. Indeed, the 14C isotope forms in the atmosphere and is then incorporated through photosynthesis, on a timescale of a few decades at most. The half-life of 14C is 5730 years. Therefore, materials produced by photosynthesis, namely plants in general, necessarily have a maximum 14C isotope content. The determination of the biomaterial or biocarbon content is carried out in accordance with ASTM D 6866 (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04) standards. ASTM D 6866 addresses "Determining the Biobased Content of Natural Range Materials Using Radiocarbon and Isotope Ratio Mass Spectrometry Analysis," while ASTM D 7026 addresses "Sampling and Reporting of Results for Determination of Biobased Content of Materials via Carbon Isotope Analysis." The second standard refers to the first in its first paragraph.

[0064] The first standard describes a test for measuring the 14C / 12C ratio of a sample and comparing it with the 14C / 12C ratio of a reference sample of 100% renewable origin, to give a relative percentage of carbon from renewable sources in the sample. The standard is based on the same concepts as 14C dating, but without applying the dating equations.

[0065] The ratio thus calculated is designated as the "pMC" (percent Modern Carbon). If the material to be analyzed is a mixture of biomaterial and fossil material (without radioactive isotopes), then the pMC value obtained is directly correlated to the amount of biomaterial present in the sample. The reference value used for 14C dating is from the 1950s. This year was chosen because of the existence of atmospheric nuclear tests that introduced large quantities of isotopes into the atmosphere after that date. The 1950 reference corresponds to a pMC value of 100. Taking into account thermonuclear tests, the current value to be used is approximately 107.5 (which corresponds to a correction factor of 0.93). The radioactive carbon signature of a modern plant is therefore 107.5. A signature of 54 pMC and 99 pMC therefore correspond to a quantity of biomaterial in the sample of 50% and 93%, respectively.

[0066] Other features and advantages of the invention will become clearer upon reading the description, figure and examples that follow.

[0067] In what follows, and unless otherwise indicated, the boundaries of a range of values ​​are included within that range, in particular in the expressions "between...and..." and "ranging from...to...".

[0068] The expression "at least one" is equivalent to the expression "one or more" and may be substituted. In the remainder of the present invention, the term chlorine has the same meaning as the term dichlorine (Cl2).

[0069] In the remainder of the present invention, the term hydrogen has the same meaning as the term dihydrogen (H2).

[0070] Compound of formula (I

[0071] As stated above, the compound(s) of formula (I) correspond(s) to the following formula (I):

[0072] [Ch

[0073] Formula (I) in which:

[0074] - ni and n2, whether identical or different, are equal to 0 or 1,

[0075] - A and B, identical or different, represent independently of each other, an aromatic ring possibly partially dehydrogenated, and possibly substituted by one or more hydrocarbon radicals, saturated or partially or totally unsaturated, comprising from 1 to 20 carbon atoms, preferably from 1 to 18 carbon atoms, preferably still from 1 to 12 carbon atoms, better from 1 to 10 carbon atoms, better still from 1 to 6 carbon atoms, typically from 1 to 3 carbon atoms,

[0076] - X represents a spacer group chosen from the divalent radical -(CRR')m- and the divalent radical >C=CRR',

[0077] - R and R', identical or different, are chosen independently of each other, from hydrogen and a hydrocarbon radical, saturated or partially or totally unsaturated, comprising from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms,

[0078] - m represents an integer between 1 and 4 inclusive. The term "aromatic ring" refers to aromatic hydrocarbon monocycles and aromatic hydrocarbon polycycles, comprising from 6 to 20 carbon atoms. The term "polycycle" refers to fused or condensed rings.

[0079] According to the present invention, in formula (I), the group(s) A is or are attached to the aromatic ring B by means of the spacer group X.

[0080] When ni and m are equal to 1, the groupings (AX) can be identical or different.

[0081] Preferably, in formula (I), X represents a divalent radical -(CRR') m .

[0082] More preferably, in formula (I), X represents a divalent radical -(CRR')m with R and R' representing a hydrogen atom.

[0083] Preferably, the compound(s) of formula (I) is or are chosen from the group consisting of xylylxylene, phenylxylylethane (PXE), benzyltoluene (BT), phenylethylphenylethane (PEPE), dibenzyltoluene (DBT), diphenylmethane (DPM), diphenylethane (DPE), one of their geometric isomers, and / or mixtures thereof.

[0084] Even more preferably, the compound(s) of formula (I) is or are chosen from the group consisting of benzyltoluene (BT), dibenzyltoluene (DBT), one of their geometric isomers, and / or mixtures thereof.

[0085] Preferably, the compound(s) of formula (I) is / are chosen from the following compound(s) of formula (IV) and / or at least one of their geometric isomers:

[0086] [Chem 2]

[0087] Formula (IV) in which: ni is an integer equal to 0 or 1.

[0088] Preferably, ni is an integer equal to 0. The process according to the invention can lead to one or more geometric isomers in ortho-, meta-, or para- position in all proportions.

[0089] According to one embodiment, the process according to the invention is a process for preparing benzyltoluene (compound of formula (I) in which ni = 0).

[0090] According to one embodiment, the process according to the invention is a process for preparing dibenzyltoluene (compound of formula (I) in which ni = 1).

[0091] According to one embodiment, the process according to the invention is a process for preparing benzyltoluene (compound of formula (IV) in which m=0) and dibenzyltoluene (compound of formula (I) in which ni=l).

[0092] The process according to the invention can lead to a mixture of benzyltoluene (BT) and dibenzyltoluene (DBT), and / or one of their geometric isomers, in a weight ratio from 1 to 0.001 to 0.001 to 1, preferably from 1 to 0.01 to 0.01 to 1.

[0093] The process according to the invention can lead to the synthesis of 70 to 100% by weight, more preferably 90 to 100% by weight, even more preferably 95 to 100% by weight, of benzyltoluene (BT).

[0094] Step (a)

[0095] As stated above, the process according to the invention comprises at least one step (a) of chlorinating at least one alkylated aromatic compound of the following formula (II):

[0096] A-(Ri)0(II)

[0097] Formula (II) in which:

[0098] A represents an aromatic ring, possibly partially dehydrogenated, Ri represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 20 carbon atoms, and o is an integer from 1 to 5, preferably equal to 1 or 2.

[0099] Preferably, Ri represents a saturated, or partially or totally unsaturated, hydrocarbon radical comprising from 1 to 18 carbon atoms, preferably from 1 to 12 carbon atoms, better still from 1 to 10 carbon atoms, better still from 1 to 6 carbon atoms, in particular from 1 to 3 carbon atoms. Preferably, in formula (II), Ri represents a saturated hydrocarbon radical comprising from 1 to 6 carbon atoms and o is an integer from 1 to 3, preferably from 1 to 2.

[0100] Preferably, the aromatic ring comprises 6 to 12 carbon atoms, especially 6 carbon atoms.

[0101] Preferably, the aromatic compound(s) of formula (II) is or are chosen from xylene, toluene, ethylbenzene, more preferably the aromatic compound of formula (II) is toluene.

[0102] In other words, the process according to the invention includes at least one step (a) of chlorination between at least one aromatic compound of formula (II), as defined above, and chlorine (Ch).

[0103] Said at least chlorination step (a) may be a radical activation reaction, preferably carried out in the presence of one or more free radicals, preferably selected from the group consisting of azobisisobutyronitrile (AIBN), benzyl peroxide or hexaphenylethane, or a radical activation reaction under the effect of ultraviolet, preferably in a wavelength range of 300 to 500 nm.

[0104] Said at least chlorination step (a) is preferably a radical activation reaction under the effect of ultraviolet rays, particularly in a wavelength range of 200 to 600 nm, better from 300 to 500 nm.

[0105] Said at least chlorination step (a) by radical activation under the effect of ultraviolet rays can be implemented using one or more mercury or LED lamps.

[0106] According to a preferred embodiment, said at least chlorination step (a) is a radical activation reaction under the effect of ultraviolet, in a wavelength range of 200 to 600 nm, preferably from 300 to 500 nm, and takes place at a pressure of -1.5 to 2 bar, preferably from 0 to 1 bar, at a temperature of -10 to 110°C, preferably from 0 to 100°C, even better from 20 to 80°C.

[0107] Said at least one chlorination step (a) is preferably carried out with at least one alkylated aromatic compound of formula (II), as defined above, in a molar amount in excess of chlorine (CL). Said at least one chlorination step (a) leads at least to the formation of hydrochloric acid (HCl), particularly in gaseous form, and at least some of the chloride of the corresponding aromatic compound of formula (II).

[0108] For the purposes of this invention, "chloride of the corresponding alkylated aromatic compound of formula (II)" means the chloride compound obtained during said at least chlorination step (a) between at least the alkylated aromatic compound of formula (II) and chlorine (CL). In other words, "chloride of the corresponding aromatic compound of formula (II)" is the product of said at least chlorination step (a).

[0109] In particular, "the chloride of the corresponding aromatic compound of formula (II)" is the product of said at least reaction of chlorine (CL) on the substituent Ri of the alkylated aromatic compound of formula (II).

[0110] Preferably, the chloride of the corresponding aromatic compound of formula (II) corresponds in particular to the following formula (II'):

[0111] A-(R'i)0

[0112] Formula (IF) in which:

[0113] A and o are such as defined in formula (II),

[0114] R'i represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 20 carbon atoms, substituted by one or more chlorine atoms.

[0115] Preferably, R'i represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 18 carbon atoms, more preferably from 1 to 12 carbon atoms, better from 1 to 10 atoms, better still from 1 to 6 carbon atoms, in particular from 1 to 3 carbon atoms, substituted by one or more chlorine atoms.

[0116] In other words, the chloride compound, obtained during said at least chlorination step (a), preferentially corresponds to formula (II') as described above.

[0117] Preferably, the chloride of the aromatic compound of formula (II) is benzyl chloride. The chloride compound of formula (II'), obtained at the end of the chlorination step(s) (a), may be in solution with at least the alkylated aromatic compound of formula (II).

[0118] According to one embodiment, the process according to the invention comprises, successively to at least said chlorination step (a), and at least one purification step (al) of the chloride of the corresponding aromatic compound of formula (II).

[0119] The purification step(s) (al) may be chosen from the group consisting of at least one distillation step (a' 1) of the corresponding aromatic compound of formula (II), at least one dechlorination step (a” l) of the reaction medium, obtained from at least step (a), at least one decolorization step (a'” l) of the reaction medium, obtained from at least step (a), and / or a mixture of said steps.

[0120] Preferably, the purification step(s) (al) is or are one or more distillation steps (a' 1) of the corresponding aromatic compound of formula (II).

[0121] In other words, preferably, the process according to the invention comprises, successively to at least said chlorination step (a), at least one distillation step (al) of the chloride of the corresponding aromatic compound of formula (II).

[0122] The purification step(s) (al) allows(s) to improve the degree of purity of the chloride of the corresponding aromatic compound of formula (II) obtained at least in step (a).

[0123] Advantageously, the distillation step(s) (a' 1) allow at least one chloride of the corresponding aromatic compound of formula (II) to be obtained having a degree of purity of at least 95%, preferably greater than or equal to 99%, more preferably greater than or equal to 99.5%.

[0124] According to one embodiment, said at least step (a) is at least one chlorination step, as defined above, of xylene leading at least to the formation of hydrochloric acid (HCl) and xylene chloride.

[0125] According to one embodiment, said at least step (a) is at least one chlorination step, as defined above, of ethylbenzene leading at least to the formation of hydrochloric acid (HCl) and at least chloroethylbenzene. Preferably, said at least step (a) is at least one chlorination step, as defined above, of toluene leading at least to the formation of hydrochloric acid (HCl) and benzyl chloride.

[0126] Preferably, said at least step (a) is a chlorination step (a) between toluene and chlorine (EC).

[0127] More preferably, during the chlorination step(s) (a), as defined above, toluene is present in an excess molar quantity relative to chlorine (CE).

[0128] The benzyl chloride obtained during said at least chlorination step (a) may be in solution in toluene.

[0129] Step (b)

[0130] As stated above, the process according to the invention comprises at least one coupling reaction step (b) between at least the chloride of the corresponding aromatic compound of formula (II), i.e. the chloride obtained in step (a), and at least one aromatic compound of the following formula (III):

[0131] B-(R2) P (III)

[0132] Formula (III) in which B represents an aromatic ring, possibly partially dehydrogenated, R2 represents a hydrogen atom or a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 20 carbon atoms, p is an integer from 1 to 5, preferably equal to 1 or 2.

[0133] Preferably, R2 represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 18 carbon atoms, more preferably from 1 to 12 carbon atoms, better from 1 to 10 atoms, better still from 1 to 6 carbon atoms, in particular from 1 to 3 carbon atoms.

[0134] Preferably, B is an aromatic ring comprising 6 to 12 carbon atoms, especially 6 carbon atoms.

[0135] Preferably, the process according to the invention comprises a coupling reaction step (b), as defined below, between at least the chloride of the corresponding aromatic compound of formula (II), i.e. the chloride obtained during step(s) (a), and at least one aromatic compound of formula (III) as defined above.

[0136] The aromatic compound of formula (III) implemented in at least said step (b) may be identical or different from the aromatic compound of formula (II) implemented in step (a).

[0137] Preferably, the aromatic compound of formula (III) used in at least said step (b) is identical to the alkylated aromatic compound of formula (II) used in at least said step (a).

[0138] Said at least one coupling reaction step (b) is preferably carried out with at least one compound of formula (III) in a molar amount in excess of the chloride of the aromatic compound of formula (II) obtained in step (a).

[0139] The said at least coupling reaction step (b) can be implemented by catalytic reaction, in particular in the presence of one or more catalysts chosen without limitation from the group consisting of iron chloride, aluminium chloride, zeolites, for example zinc-doped aluminosilicates.

[0140] The said at least coupling reaction step (b) can in particular be carried out at a temperature ranging from 50 to 150°C in the presence of one or more catalysts, preferably chosen from among zeolites, for example zinc-doped aluminosilicates or iron chloride or aluminium chloride.

[0141] Said at least one coupling reaction step (b) leads at least to the formation of hydrochloric acid (HCl), preferably in gaseous form, and at least one compound of formula (I) and / or at least one of its geometric isomers.

[0142] Preferably, said at least one coupling reaction step (b) is at least a coupling reaction of benzyl chloride, obtained at the end of step(s) (a) of chlorination, and toluene, leading to the formation of at least hydrochloric acid (HCl) and at least one compound of formula (IV) and / or at least one of its geometric isomers:

[0143] [Chem 2]

[0144] Formula (IV) in which: ni is an integer equal to 0 or 1, preferably 0.

[0145] According to one embodiment, said at least coupling reaction step (b) is a coupling reaction step of benzyl chloride, obtained at the end of chlorination step(s) (a), and toluene.

[0146] According to one embodiment, said at least coupling reaction step (b) is a coupling reaction step of xylene chloride, obtained at the end of chlorination step(s) (a), and xylene, to lead at least to the formation of xylylxylene and hydrochloric acid.

[0147] According to one embodiment, said at least coupling reaction step (b) is a coupling reaction step of benzyl chloride, obtained at the end of chlorination step(s) (a), and benzene, to lead at least to the formation of diphenylmethane (DPM).

[0148] According to one embodiment, said at least coupling reaction step (b) is a coupling reaction step of chloroethylbenzene, obtained at the end of chlorination step(s) (a), and ethylbenzene, to lead at least to the formation of hydrochloric acid and phenylethylphenylethane (PEPE).

[0149] Preferably, said at least coupling reaction step (b) is a coupling reaction step of benzyl chloride, obtained at the end of chlorination step(s) (a), and toluene.

[0150] Preferably, in at least said coupling reaction step (b), toluene is present in a molar amount in excess relative to benzyl chloride.

[0151] The ratio of benzyltoluene (BT) and / or dibenzyltoluene (DBT) depends on the ratio of benzyl chloride to toluene during said at least step (b). The greater the amount of toluene during said at least step (b), the more the coupling reaction favors the formation of benzyltoluene (BT).

[0152] Said at least one coupling reaction step (b) between benzyl chloride and toluene takes place preferentially in the presence of one or more Friedel and Crafts catalysts, in particular iron(III) chloride, according to a process as described in document EP 0435 737.

[0153] Preferably, the process according to the invention includes at least one separation step, in particular at least one distillation step, after said coupling reaction step (b).

[0154] Advantageously, the process according to the invention includes at least one step of separating benzyltoluene and dibenzyltoluene.

[0155] Step (c)

[0156] As stated above, the process according to the invention includes at least one recovery step (c) of the hydrochloric acid (HCl) formed at the end of at least said step (a) and / or at least said step (b).

[0157] The recovery step(s) (c) may collect hydrochloric acid (HCl) directly or indirectly formed as a result of at least said step (a) and / or at least said step (b).

[0158] By "directly formed at the end of step(s) (a) and / or step(s) (b)", it is understood in the context of the present invention that the hydrochloric acid (HCl) is recovered in gaseous form at the end of step(s) (a) and / or step(s) (b).

[0159] By "indirectly formed at the end of step(s) (a) and / or step(s) (b)", it is understood in the context of the present invention that hydrochloric acid (HCl) in gaseous form, formed at the end of step(s) (a) and / or step(s) (b), can be absorbed by water, in particular in a column with water, to form an aqueous solution of hydrochloric acid (HCl).

[0160] In other words, the recovery step(s) (c) allows the hydrochloric acid from step(s) (a) and / or step(s) (b) to be treated in either gaseous or aqueous form. Thus, at least one step (c) can recover at least one aqueous solution of hydrochloric acid (HCl).

[0161] The recovery step(s) (c) may thus include a step of absorption of hydrochloric acid (HCl) in gaseous form, formed at the end of step(s) (a) and / or step(s) (b), in water.

[0162] Preferably, the process according to the invention includes at least one recovery step (c) of the hydrochloric acid (HCl) formed at the end of step(s) (a) and / or step(s) (b).

[0163] Preferably, the recovery step(s) (c) is or are implemented to recover hydrochloric acid (HCl) upstream of at least said chlorination step (a).

[0164] Preferably, step(s) (c) recover hydrochloric acid (HCl) directly or indirectly formed: at the end of said at least chlorination step (a) of toluene leading at least to the formation of hydrochloric acid and benzyl chloride, and / or, preferably and at the end of said at least coupling reaction step (b) between benzyl chloride and toluene leading at least to the formation of hydrochloric acid and at least benzyltoluene (BT) and / or dibenzyltoluene (DBT) of formula (III) as defined above.

[0165] Step (d)

[0166] As stated above, the process according to the invention includes at least one step of converting (d) hydrochloric acid (HCl), recovered at the end of step (c), into chlorine (CL).

[0167] In other words, said at least step (d) is intended to convert hydrochloric acid (HCl), whether in gaseous or aqueous form, into chlorine (Cl2).

[0168] This at least conversion step (d) may, in particular, be carried out by electrolysis of hydrochloric acid (HCl) to chlorine (Cl2), by oxidation of hydrochloric acid (HCl) by nitric acid (HNO3) (Kel-Chlor process), or by catalytic oxidation of hydrochloric acid (HCl) (Deacon, Shell cor, MT chlorine process), or any other synthesis process. Preferably, this at least conversion step (d) is carried out by electrolysis of hydrochloric acid (HCl).

[0169] In other words, said at least one conversion step (d) includes at least one electrolysis of hydrochloric acid (HCl), formed at the end of step(s) (a) and / or step(s) (b), into chlorine (Cb).

[0170] According to an advantageous embodiment, said at least conversion step (d) is an electrolysis of hydrochloric acid (HCl) leading to the formation of chlorine (Cb) and hydrogen (H2).

[0171] In the case where said at least conversion step (d) is an electrolysis of hydrochloric acid (HCl), the hydrogen formed can be utilized, preferably either by being partially or totally stored in the compound(s) of formula (I) synthesized in said at least step (b) (in the hydrogenated form of the compound(s) of formula (I) and / or at least one of its geometric isomers obtained at the end of step(s) (b)), or as an energy source for producing heat or electricity according to methods known to those skilled in the art.

[0172] Preferably, the process according to the invention comprises: at least one step of conversion (d) of hydrochloric acid (HCl) into chlorine (Cl2) and hydrogen (H2) carried out by electrolysis of the hydrochloric acid formed at the end of step(s) (a) and / or step(s) (b), at least one step of valorization (f) of the hydrogen, preferably at least one step of storage of all or part of the hydrogen (H2) in the compound(s) of formula (I) and / or at least one of its geometric isomers synthesized at step(s) (b).

[0173] Advantageously, when said at least conversion step (d) is implemented by electrolysis of hydrochloric acid (HCl), the water used can be recovered to absorb the hydrochloric acid (HCl) in gaseous form formed at the end of step(s) (a) and / or step(s) (b).

[0174] Advantageously, the process according to the invention comprises: at least one conversion step (d) of hydrochloric acid (HCl) into chlorine (Cl2) and hydrogen (H2) carried out by electrolysis of the hydrochloric acid formed at the end of the step(s) (a) of chlorination of toluene, as defined above, and / or of the coupling reaction step (b) between benzyl chloride and toluene, as defined above, at least one hydrogen valorization step (f), preferably at least one storage step of all or part of the hydrogen (H2) in the benzyltoluene (BT) and / or dibenzyltoluene (DBT) of formula (III) obtained in said at least step (b).

[0175] Step (e)

[0176] As stated above, the process according to the invention includes at least one transfer step (e) of chlorine (CE), from at least said conversion step (d), to at least said chlorination step (a).

[0177] Said at least transfer step (e) thus allows the chlorine (Cl2) to be recycled as a reagent for at least said chlorination step (a).

[0178] In other words, said at least transfer step (e) is a chlorine (Cl2) recirculation step to at least said chlorination step (a). In this way, the chlorine (Cl2), from at least the conversion step (d), is consumed by at least said chlorination step (a).

[0179] Said at least transfer step (e) can be implemented at a temperature ranging from 0°C to 50°C, preferably at a temperature in the vicinity of 27°C.

[0180] Additional step(s)

[0181] As previously stated, the process according to the invention optionally includes at least one step of adding (e') chlorine (Cl2), which may be obtained from at least one process of electrolysis of at least one aqueous solution of sodium chloride (NaCl) or from any other synthesis process, to at least said step (a).

[0182] Preferably, the process according to the invention includes at least one step of adding chlorine (Cl2), which may be obtained from at least one process of electrolysis of at least one aqueous solution of sodium chloride (NaCl) or from any other synthesis process, to at least said step (a).

[0183] The purpose of said at least one addition step (e') is to add chlorine (Cl2), which is not produced by at least said at least one conversion step (d), to the chlorination step (a). In other words, said at least one step (e') is to add "fresh" chlorine (Cl), i.e., chlorine that is not produced by at least said at least one conversion step (d), to be consumed as a reactant by at least said chlorination step (a).

[0184] Thus said at least step (e') makes it possible to complete the supply of chlorine (CE), resulting from said at least conversion step (d).

[0185] Said at least step (e') includes at least the addition of chlorine (Cl2), which may be obtained from at least one electrolysis process of at least one aqueous solution of sodium chloride (NaCl), hydrochloric acid (HCl) obtained by at least one synthesis process of at least one isocyanate, in particular carried out by phosgenation of at least one amine, hydrochloric acid (HCl) obtained by at least one synthesis process of at least one carbonate ester carried out by phosgenation of at least one alcohol, or hydrochloric acid (HCl) obtained by at least one synthesis process of at least one methanesulfonic acid.

[0186] Preferably, said at least step (e') includes at least the addition of chlorine (Cl2) from at least one electrolysis process of at least one aqueous solution of sodium chloride (NaCl).

[0187] The process according to the invention may further comprise at least one recovery step (g1) of at least of said alkylated aromatic compound of formula (II) not having reacted to said at least step (a) and / or said at least step (b) and at least one transfer step (g2) of at least of said alkylated aromatic compound of formula (II) to at least step(s) (a) and / or (b).

[0188] The purpose of said at least step (g1) is to recover the excess of the alkylated aromatic compound of formula (II), implemented during said at least step (a) and / or (b), and said at least step (g2) is to transfer said excess of the alkylated aromatic compound of formula (II) to at least said step (a) and / or (b).

[0189] The said at least steps (g1) and (g2) thus allow the alkylated aromatic compound(s) of formula (II), as defined above, which have not reacted, to be consumed as a reactant by at least step(s) (a) and / or (b).

[0190] In other words, preferably, the process according to the invention comprises at least one recovery step (g1) of the excess of alkylated aromatic compound of formula (II), from said at least step (a) and / or said at least step (b), and at least one transfer step (g2) of said excess to at least step(s) (a) and / or (b).

[0191] The process according to the invention may also include at least one step of adding (g3) at least one alkylated aromatic compound of formula (II), which is not carried out at least in step (a) and / or (b), in at least step (a) and / or (b).

[0192] In other words, step (g3) is intended to add at least one alkylated aromatic compound of formula (II) "fresh", i.e. not implemented at least in step (a) and / or (b), to be consumed as a reactant by at least step (a) and / or (b).

[0193] Preferably, the process according to the invention further comprises: at least one recovery step (g1) of excess toluene carried out in the chlorination step (a) of toluene and / or excess toluene carried out in the coupling reaction step (b) between benzyl chloride and toluene, at least one addition step (g2) of the toluene recovered by at least step (g1) to the step(s) (a) and (b) as defined above.

[0194] According to a preferred embodiment, the method according to the invention comprises:

[0195] (i) at least one step (a) of chlorination of at least one alkylated aromatic compound of formula (II) as defined above, leading at least to the formation of hydrochloric acid (HCl) and at least to the chloride of the corresponding aromatic compound of formula (II) as defined above,

[0196] (ii) at least one coupling reaction step (b) between at least the chloride of the aromatic compound of formula (II), obtained at the end of at least step (a), and at least one aromatic compound of formula (III) as defined above, leading at least to the formation of hydrochloric acid (HCl) and at least one aromatic compound of formula (I) and / or at least one of its geometric isomers, (iii) at least one recovery step (c) of the hydrochloric acid (HCl) formed at the end of at least step(s) (a) and / or (b),

[0197] (iv) at least one conversion step (d) of hydrochloric acid (HCl) into chlorine (Ch) and hydrogen (H2) implemented by electrolysis of hydrochloric acid (HCl),

[0198] (v) at least one transfer step (e) of chlorine (Cl2), from at least said conversion step (d), to at least said chlorination step (a),

[0199] (vi) optionally at least one step of adding (e') chlorine (Cl2), which may be obtained from at least one process of electrolysis of at least one aqueous solution of sodium chloride (NaCl) or from any other synthesis process, in step (a),

[0200] (vii) at least one hydrogen (H2) valorization step from at least step (d),

[0201] (viii) optionally at least one recovery step (g1) of at least of said alkylated aromatic compound of formula (II) not having reacted in step (a) and / or step (b) and at least one transfer step (g2) of at least of said alkylated aromatic compound of formula (II) to at least step (a) and / or (b).

[0202] The chlorination step(s) (a), on the one hand, and the coupling reaction step(s) (b), on the other hand, can be implemented at different sites or at the same site.

[0203] Preferably, the chlorination step(s) (a), on the one hand, and the coupling reaction step(s) (b), on the other hand, are implemented at the same site in order to reduce investment costs and the carbon footprint associated with transporting the chloride of the aromatic compound of formula (II) from one site to another.

[0204] Process for the preparation of benzyltoluene (BT) and / or dibenzyltoluene (DBT)

[0205] Another object of the present invention consists of a process for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) of the following formula (IV):

[0206] [Chem 2]

[0207] <IV)

[0208] Formula (IV) wherein: ni is an integer with the value 0, 1, preferably 0. Said process comprising: i) at least one chlorination step (a) of toluene leading to at least the formation of hydrochloric acid (HCl) and benzyl chloride, ii) at least one coupling reaction step (b) between the benzyl chloride from the chlorination step (a) and toluene, leading to at least the formation of benzyltoluene (BT) and / or dibenzyltoluene (DBT) and hydrochloric acid, iii) at least one recovery step (c) of the hydrochloric acid formed at the end of at least step(s) (a) and / or (b), iv) at least one conversion step (d) of hydrochloric acid (HCl) to chlorine (CF), v) at least one transfer step (e) of chlorine (Cl2), from at least the conversion step (d), to at least said chlorination step (a), vi) optionally at least one chlorine (Cl2) addition step (e'),capable of being obtained from at least one electrolysis process of at least one aqueous solution of sodium chloride (NaCl) or from any other synthesis process, in step (a).

[0209] Preferably, step(s) (a), (b), (c), (d), (e) and (e') are as defined previously.

[0210] The process for preparing benzyltoluene (BT) and / or dibenzyltoluene (DBT) of formula (IV) as defined above may further include at least one optional step (a'), (f) and / or (gl), (g2) and (g3) as defined above.

[0211] Advantageously, benzyltoluene (BT) and / or dibenzyltoluene (DBT) according to the process according to the invention exhibits a high degree of purity and meets the specification IEC 60867 and / or the specification DIN 91 437. The following examples serve to illustrate the invention without, however, being limiting in nature.

[0212] 5

[0213] EXAMPLES

[0214] Example 1

[0215] In the following example, a process for preparing pure benzyltoluene (BT) (i.e. not containing dibenzyltoluene) according to the invention is implemented.

[0216] We calculate the quantity of hydrochloric acid (HCl) recycled per tonne of benzyltoluene (BT) produced by the process according to the invention.

[0217] For each quantity of hydrochloric acid (HCl) recycled per tonne of benzyltoluene (BT) produced by the process according to the invention, the volumes of "fresh" chlorine (CL) from an electrolysis process of aqueous sodium chloride solutions required for the chlorination step (a) of toluene in the presence of chlorine (CL) are calculated, as well as the quantity of sodium hydroxide (NaOH) produced during this electrolysis process, the quantity of NaCl salt consumed during this electrolysis process, and the quantity of hydrogen from this electrolysis process.

[0218] The quantities are given in Table 1 below:

[0219] [Table 1]

[0220] The results show that the more HCl the process according to the invention recycles, the lower the volumes of fresh chlorine (C12), i.e., from an electrolysis process of aqueous sodium chloride solutions, required to carry out the toluene chlorination step. Similarly, the higher the quantity of HCl recycled per tonne of pure BT, the lower the quantity of sodium hydroxide (NaOH), co-produced during the salt electrolysis process.

[0221] Similarly, the more HCl is recycled per tonne of pure BT, the more the amount of hydrogen co-produced during the salt electrolysis process decreases.

[0222] Similarly, the more HCl is recycled per tonne of pure BT, the less salt is consumed by the electrolysis process.

[0223] The results confirm that the process according to the invention makes it possible to preserve natural resources, such as sodium chloride salts, needed for the production of new volumes of chlorine (CL) and to limit the co-production of caustic soda.

[0224] Example 2

[0225] In the following example, the volume of hydrogen recovered is calculated as a function of the chlorine recycling rate (CL) during the conversion step (d) of the process for preparing benzyltoluene and / or dibenzyltoluene according to the invention.

[0226] Table 2 shows the quantities produced of chlorine, sodium hydroxide and hydrogen (H2) in the case of hydrolysis of an aqueous solution of salt (NaCl).

[0227] Table 3 shows the amounts produced of chlorine (Cl2) and hydrogen (H2) when hydrochloric acid (HCl) is converted by an electrolysis process.

[0228] The results are given in Tables 2 and 3 below:

[0229] Table 2] [Table 3]

[0230] The results show that the conversion step (d) of the process according to the invention makes it possible to obtain the same quantity of chlorine (CL) as in an electrolysis process of aqueous sodium chloride solution intended to produce volumes of "fresh" chlorine (CL) intended to be consumed in the chlorination step (a).

[0231] The process according to the invention makes it possible to optimize the valorization of products necessary for the decarbonization of industry.

Claims

DEMANDS 1. Process for preparing at least one compound of formula (I) Formula (I) in which: - ni and m, identical or different, equal to 0 or 1, - A and B, identical or different, represent independently of each other, an aromatic ring possibly partially dehydrogenated, and possibly substituted by one or more hydrocarbon radicals, saturated or partially or totally unsaturated, comprising from 1 to 20 carbon atoms, preferably from 1 to 18 carbon atoms, preferably still from 1 to 12 carbon atoms, better from 1 to 10 carbon atoms, better still from 1 to 6 carbon atoms, typically from 1 to 3 carbon atoms, - X represents a spacer group chosen from the divalent radical -(CRR')m- and the divalent radical >C=CRR', - R and R', identical or different, are chosen independently of each other, from hydrogen and a hydrocarbon radical, saturated or partially or totally unsaturated, comprising from 1 to 6 carbon atoms, preferably from 1 to 3 carbon atoms, - m represents an integer between 1 and 4 inclusive, and said process comprising: i) at least one chlorination step (a) of at least one alkylated aromatic compound of the following formula (II): A-(Ri)0(II) Formula (II) in which: A represents an aromatic ring, possibly partially dehydrogenated, Ri represents a saturated hydrocarbon radical, or partially or totally unsaturated, linear or branched, comprising from 1 to 20 carbon atoms, and o is an integer from 1 to 5, preferably equal to 1 or 2, said chlorination step (a) leading at least to the formation of hydrochloric acid (HCl) and at least one chloride of the aromatic compound of formula (II) ii) at least one coupling reaction step (b) between at least the chloride of the aromatic compound of formula (II), obtained at the end of said at least chlorination step (a), and at least one aromatic compound of the following formula (III): B-(R2) P (III) Formula (III) wherein B represents an aromatic ring, optionally partially dehydrogenated, R2 represents a hydrogen atom or a saturated, or partially or totally unsaturated, hydrocarbon radical comprising from 1 to 20 carbon atoms, p is an integer from 1 to 5, preferably equal to 1 or 2, said coupling reaction step (b) leading at least to the formation of hydrochloric acid (HCl) and at least one aromatic compound of formula (II), iii) at least one recovery step (c) of the hydrochloric acid (HCl) formed at the end of at least step(s) (a) and / or (b), iv) at least one conversion step (d) of hydrochloric acid (HCl) to chlorine (Cl2), v) at least one transfer step (e) of chlorine (Cl2), from said at least conversion step (d), to said at least chlorination step (a), vi) optionally at least one step (e') of adding chlorine (Cl2),capable of being produced by at least one electrolysis process of at least one aqueous solution of sodium chloride (NaCl) or by any other synthesis process, at said at least chlorination step (a).

2. A process according to claim 1, characterized in that the compound(s) of formula (I) is or are selected from the group consisting of xylylxylene, phenylxylylethane (PXE), benzyltoluene (BT), phenylethylphenylethane (PEPE), dibenzyltoluene (DBT), diphenylmethane (DPM), diphenylethane (DPE), one of their geometric isomers, and / or mixtures thereof, preferably selected from the group consisting of xylene, phenylxylylethane (PXE), benzyltoluene (BT), phenylethylphenylethane (PEPE), dibenzyltoluene (DBT), one of their geometric isomers, and / or mixtures thereof.

3. A method according to claim 1 or 2, characterized in that the compound(s) of formula (I) is or are chosen from the following compound(s) of formula (IV) and / or at least one of their geometric isomers: [Chem 2] Formula (IV) in which: ni is an integer equal to 0 or 1, preferably 0.

4. A process according to any one of the preceding claims, characterized in that the alkylated aromatic compound of formula (II) is or are selected from xylene, toluene, ethylbenzene, more preferably the aromatic compound of formula (II) is toluene.

5. A process according to any one of the preceding claims, characterized in that said at least chlorination step (a) is a radical activation reaction, preferably under the effect of ultraviolet rays.

6. A process according to any one of the preceding claims, characterized in that the alkylated aromatic compound(s) of formula (II) is or are in a molar amount in excess with respect to chlorine (Ch) in said at least chlorination step (a).

7. A process according to any one of the preceding claims, characterized in that the chloride of the aromatic compound of formula (II) corresponds to the following formula (IF): A-(R'i), Formula (II') in which: A and o are such as defined in formula (II), R'i represents a saturated, or partially or totally unsaturated, linear or branched hydrocarbon radical, comprising from 1 to 20 carbon atoms, substituted by one or more chlorine atoms.

8. A process according to any one of the preceding claims, characterized in that the chloride of the aromatic compound of formula (II) is benzyl chloride.

9. A process according to any one of the preceding claims, characterized in that said at least conversion step (d) is an electrolysis of hydrochloric acid (HCl) leading to the formation of chlorine (Cb) and hydrogen (H2).

10. A process according to the preceding claim, characterized in that it further comprises at least one step of valorization (f) of hydrogen (H2), preferably at least one step of storage (f) of all or part of the hydrogen (H2) in the compound(s) of formula (I) synthesized in said at least step (b).

11. A process according to any one of the preceding claims, characterized in that it comprises at least one step of adding (e') chlorine (Cl2), which may be obtained from at least one process of electrolysis of at least one aqueous solution of sodium chloride (NaCl) or from any other synthesis process, in step (a).

12. A process according to any one of the preceding claims, characterized in that it comprises at least one recovery step (g1) of at least of said alkylated aromatic compound of formula (II) not having reacted in step (a) and / or step (b) and at least one transfer step (g2) of at least of said alkylated aromatic compound of formula (II) to at least step(s) (a) and / or (b).

13. A process according to any one of the preceding claims, characterized in that it comprises at least one step of adding (g3) at least one alkylated aromatic compound of formula (II), which is not carried out at least in step (a) and / or (b), in said at least step (a) and / or said at least step (b).

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