EP2872498A1

EP2872498A1 - Method for producing polyglycerol (poly)carbonate

Info

Publication number: EP2872498A1
Application number: EP13735273.8A
Authority: EP
Inventors: Gérard Mignani; Julien DEBRAY; Eric Da Silva; Marc Lemaire; Yann Raoul
Original assignee: Centre National de la Recherche Scientifique CNRS; Universite Claude Bernard Lyon 1 UCBL; Rhodia Operations SAS; FONDS DE DEVELOPPEMENT DES FILIERES DES OLEAGINEUX ET PROTEAGINEUX FIDOP
Current assignee: Centre National de la Recherche Scientifique CNRS; Universite Claude Bernard Lyon 1 UCBL; Rhodia Operations SAS; FONDS DE DEVELOPPEMENT DES FILIERES DES OLEAGINEUX ET PROTEAGINEUX FIDOP
Priority date: 2012-07-11
Filing date: 2013-07-10
Publication date: 2015-05-20
Also published as: US20150152079A1; WO2014009421A1; CN104583190A; US9242956B2; FR2993269A1; FR2993269B1

Abstract

The invention relates to a method for producing a compound of formula (I), comprising the reaction, in the presence of a catalytic system comprising a single rare earth oxide or a mixture of rare earth oxides, of an alkyl carbonate or an alkylene carbonate with a polyol of formula (II), wherein p is a whole number between 2 and 10.

Description

Process for the preparation of polyglycerol (poly) carbonate

The present invention relates to a process for the preparation of polyglycerol (poly) carbonate.

Glycerol carbonate synthesis processes are widely described in the literature.

Processes using organic carbonates have been developed. EP0739888 discloses a process for the preparation of glycerol carbonate by reaction of glycerol and a cyclic organic carbonate in the presence of a solid catalyst comprising a bicarbonated or hydroxylated anionic macroporous resin or a zeolite of the X or Y three-dimensional type comprising basic sites, at a temperature between 50 and 110 ° C. The yield of the reaction is of the order of 90%. To obtain this yield, it is however necessary to extract the ethylene glycol formed during the reaction. The process is applicable to pure glycerol as well as to glycerines.

Also known from US2010 / 0209979 a process for preparing glycerol carbonate by reaction between dimethyl carbonate and glycerol by transesterification catalyzed by a lipase.

JP06329663 discloses a process for the preparation of glycerol carbonate by reaction between ethylene carbonate and glycerol catalyzed by oxides of aluminum, magnesium, zinc, titanium, lead. Other methods have been developed by CaO catalysis. However, these catalysts are not stable and are in particular degraded by water and do not make it possible to carry out the process continuously.

There are other methods including phosgene and urea. The phosgene process however has the disadvantage of being highly toxic and is therefore not suitable for the preparation of products used in the manufacture of food, cosmetic or pharmaceutical compositions.

From EP0955298 there is thus known a process for the synthesis of glycerol carbonate consisting in the reaction of glycerol with urea in the presence of a metal or organometallic salt type catalyst and having Lewis acid sites. The molar yield obtained is between 40 and 80% relative to glycerol.

However, the urea processes generate ammonia in high proportion, it is necessary to neutralize this ammonia in salt form and these ammonia salts are not valued. Disadvantages in terms of cost, difficulty of purification and sometimes of respect for the environment (in particular rejection of dioxane and / or glycidol, use of glycidol, use of tin catalyst, use of acetonitrile) are also disclosed.

There is therefore a need to provide a process that is easily industrializable, that can be implemented continuously and that does not present a risk, particularly in terms of toxicity.

The present invention relates to a process for the preparation by transcarbonation of compound of formula (I)

in which R ¹ represents:

a group (CH ₂ CH (OH) CH ₂ O) _n H; or

a group (CH ₂ CH (OH) CH ₂ 0) _m CH ₂ R ² ;

n is an integer of 1 to 10, preferably 1 to 5, for example n is 1 or 2;

m represents an integer from 0 to 10, preferably from 0 to 5, for example m represents 0 or 1;

R ² representative

said process comprising reacting, in the presence of a catalytic system comprising as a catalytic unit a rare earth oxide alone or a mixture of rare earth oxides, between an alkyl carbonate or an alkylene carbonate and a polyol of formula (II)

(I I)

in which p represents an integer of 2 to 10.

In one embodiment, in the compound of formula (I) R ¹ represents (CH ₂ CH (OH) CH ₂ O) _n H. In another embodiment, in the compound of formula (I) R represents (CH ₂ CH (OH) CH ₂ 0) _m CH ₂ R ² .

Preferably, in the compound of formula (II) p represents an integer of 2 to 5, preferably 2 or 3.

In the context of the present invention, the expression "comprised between x and y" also intends to cover the terminals x and y. Thus, "between x and y" can be understood, within the scope of the invention, as meaning "ranging from x to y".

In the process according to the invention, the alkyl carbonate may be a compound of formula

(III)

in which R ³ and R ⁴ , which are identical or different, represent:

a linear or branched C ₁ -C ₂₀ alkyl group;

a C ₅ to C _M aryl group, preferably C ₆ to C, optionally substituted with one or more substituents, in particular chosen from:

- alkyl to C _9, preferably C l -C _5;

a C ₅ to C 6, preferably C ₆ to C ₆ , aryl group, preferably

C ₆ to C ₀ ; optionally substituted;

an alkyl-aryl group of formula -Q -Ar ¹ in which Q represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar represents a C ₆ -C ₆ , preferably C _6, aryl group; optionally substituted; polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5;

a C ₅ to C ₆ cycloalkyl group optionally substituted by one or more substituents, in particular chosen from

- alkyl to C _9, preferably C l -C _5;

a C ₅ to C, preferably C ₆ to C, preferably C ₆ to C ₁₀ , aryl group which is optionally substituted; - alkyl-aryl group of formula -Q ² -Ar ² wherein Q ² represents an alkyl residue to C _9, preferably C, to C ₅ and Ar ² represents an aryl group of C ₆ to C _M, of preferably C ₆ , optionally substituted;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) q-OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5; or

a heteroaryl group, preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur; optionally substituted with one or more substituents chosen in particular from:

- alkyl to C _9, preferably C l -C _5;

a C ₅ to C, preferably C ₆ to C, preferably C ₆ to C ₁₀ aryl group, optionally substituted;

- alkyl-aryl group of formula -Ar ³ -Q ³ wherein Q ³ represents an alkyl residue to C _9, preferably C, to C ₅ and Ar ³ represents an aryl group of C ₆ to C _M, of preferably C ₆ , optionally substituted;

- an alkoxy group -C _9, preferably C l -C _5;

an alkyl-aryl group of formula -Q ⁴ -Ar ⁴ in which Q ⁴ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁴ represents a C ₆ -C ₆ aryl group, preferably at C ₆ , optionally substituted.

Preferably, in the process of the invention, R ³ and R ⁴ , which are identical or different, represent:

a linear or branched C ₁ -C 10 alkyl group, for example methyl, ethyl, propyl or butyl;

an aryl group of C ₆ , C ₀ or C, optionally substituted with one or more substituents, in particular chosen from:

- alkyl to C _5, for example methyl, ethyl; an optionally substituted phenyl group;

an alkyl-aryl group of formula -Q-Ar ¹ in which Q ¹ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue, and Ar ¹ represents a optionally substituted phenyl group, preferably methylphenyl, ethylphenyl;

- an alkoxy group at C _5, for example methoxy, ethoxy;

a C ₅ to C ₆ cycloalkyl group optionally substituted by one or more substituents, in particular chosen from:

an alkyl-aryl group of formula -Q ² -Ar ² in which Q ² represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ² represents an optionally substituted phenyl group, preferably methylphenyl or ethylphenyl; ;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group at C _5, for example methoxy, ethoxy; or

a heteroaryl group preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur, for example aniline, optionally substituted with one or more substituents, in particular chosen among

an alkyl-aryl group of formula -Q ³ -Ar ³ in which Q ³ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ³ represents an optionally substituted phenyl group, preferably methylphenyl or ethylphenyl; ;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C 1 to C ₁₀ , preferably C 1 to C ₅ , alkyl group;

- an alkoxy group at C _5, for example methoxy, ethoxy;

an alkyl-aryl group of formula -Q ⁴ -Ar ⁴ in which Q ⁴ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁴ represents an optionally substituted phenyl group. Advantageously, the alkyl carbonate is dimethyl carbonate, diethyl carbonate. Preferably, the alkyl carbonate is dimethyl carbonate.

According to the invention, alkylene carbonate is understood to mean a compound of formula (IV)

(IV)

in which

R ⁵ , R ⁶ , R ⁷ and R ^{8, which are} identical or different, are chosen from:

a hydrogen;

a linear, branched or cyclic C ₁ to C ₉ , preferably C 1 to C ₅ , hydrocarbon group which may comprise one or more heteroatoms, chosen in particular from oxygen, nitrogen or sulfur, and which may comprise one or more several OH substituents;

a group of formula -CH ₂ -R ¹⁰ , in which R ¹⁰ represents a hydrocarbon group, Ci-C ₉ , preferably Ci-C ₅ , linear, branched or cyclic, which may comprise one or more heteroatoms, chosen in particular from oxygen, nitrogen or sulfur, and may include one or more OH substituents;

a group of formula C (O) OR ¹¹ , in which R ¹¹ represents a hydrogen atom, a Ci-C ₉ alkyl group, preferably a Ci-C ₅ alkyl group, for example methyl or ethyl;

a C ₅ to C ₆ cycloalkyl group optionally substituted by one or more substituents, chosen in particular from:

- alkyl to C _9, preferably C l -C _5; an aryl group of C ₅ -C _M, preferably C ₆ to _4, preferably C ₆ to C _0, is optionally substituted;

an alkyl-aryl group of formula -Q ⁵ -Ar ⁵ in which Q ⁵ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁵ represents a C ₆ -C ₆ aryl group, preferably C ₆ , optionally substituted;

- an alkoxy group -C _9, preferably C l -C _5; a heteroaryl group, preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur optionally substituted by one or more substituents, in particular chosen from:

- alkyl to C _9, preferably C l -C _5; an aryl group C ₅ to C, preferably C ₆ to ₄ , preferably C ₆ to C ₀ , optionally substituted;

an alkyl-aryl group of formula -Q ⁶ -Ar ⁶ in which Q ⁶ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁶ represents a C ₆ -C ₆ aryl group, preferably C ₆ , optionally substituted;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which n represents an integer between 2 and 5 and R ⁵ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5;

a C ₆ to C ₆ aryl group, optionally substituted by one or more substituents, in particular chosen from:

- alkyl-aryl group of formula -Q ⁷ -Ar ⁷ wherein Q ⁷ represents an alkyl residue to C _9, preferably C, to C ₅ and Ar ⁷ represents an aryl group of C ₆ to ₄ to preferably C ₆ , optionally substituted;

- an alkoxy group -C _9, preferably C l -C _5;

an alkyl-aryl group of formula -Q ⁸ -Ar ⁸ in which Q ⁸ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁸ represents a C ₆ -C ₆ aryl group, preferably C ₆ , optionally substituted;

or one of R ⁵ / R ⁶ and one of R ⁷ / R ⁸ together with the carbon atoms bearing them a double bond; or one of R ⁵ / R ⁶ and one of R ⁷ / R ⁸ together with the carbon atoms carrying them a double bond which is included in an aryl group, especially phenyl, formed by R ⁶ and R ⁷ with the two carbons carrying them. In the process of the invention, R ⁵ , R ⁶ , R ⁷ and R ^{8, which are} identical or different, are preferably chosen from: a hydrogen;

a linear or branched C ₁ to C ₉ , preferably C 1 to C ₅ , alkyl group which may comprise one or more heteroatoms, chosen in particular from oxygen, nitrogen or sulfur, and which may comprise one or more OH substituents; for example methylene, ethylene;

a group of formula -CH ₂ -R ¹⁰ , in which R ⁰ represents a linear or branched C ₁ -C ₅ hydrocarbon-based group which may comprise one or more heteroatoms, chosen in particular from oxygen, nitrogen or sulfur, and may include one or more OH substituents, for example ethylene, methylene;

a group of formula C (O) OR ¹¹ , in which R ¹¹ represents a hydrogen atom or a C ₁ -C ₅ alkyl group, for example methyl or ethyl;

an alkyl-aryl group of formula -Q ⁵ -Ar ⁵ in which Q ⁵ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁵ represents an optionally substituted phenyl group, preferably methylphenyl or ethylphenyl; ;

- an alkoxy group at C _5, for example methoxy, ethoxy;

a heteroaryl group, preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur, for example aniline, optionally substituted with one or more substituents; , in particular chosen from:

- alkyl, C l -C _5, e.g. methyl, ethyl; an optionally substituted phenyl group;

an alkyl-aryl group of formula -Q ⁶ -Ar ⁶ in which Q ⁶ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁶ represents an optionally substituted phenyl group, preferably methylphenyl, ethylphenyl ;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group; - an alkoxy group at C _5, for example methoxy, ethoxy;

a C ₆ , C ₁₀ or C ₆ aryl group, optionally substituted with one or more substituents chosen in particular from:

- alkyl to C _5, for example methyl, ethyl;

an optionally substituted phenyl group; an alkyl-aryl group of formula -Q ⁷ -Ar ⁷ in which Q ⁷ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁷ represents an optionally substituted phenyl group, preferably methylphenyl or ethylphenyl;

a polyalkoxy group of formula - (OCH ₂ CH ₂ ) q-OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C 1 to C ₁₀ , preferably C 1 to C ₅ , alkyl group;

- alkoxy, Ci to C _5, for example methoxy, ethoxy;

an alkyl-aryl group of formula -Q ⁸ -Ar ⁸ in which Q ⁸ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁸ represents an optionally substituted phenyl;

or one of R ⁵ / R ⁶ and one of R ⁷ / R ⁸ together with the carbon atoms bearing them a double bond; or one of R ⁵ / R ⁶ and one of R ⁷ / R ⁸ together with the carbon atoms carrying them a double bond which is included in an aryl group, especially phenyl, formed by R ⁶ and R ⁷ with the two carbons carrying them.

Advantageously the alkyl carbonate may be ethylene carbonate, propylene carbonate, dibutylene carbonate or dihexylene carbonate.

According to the invention, the catalytic system comprises as a catalytic unit a rare earth oxide or a mixture of rare earth oxides.

In one embodiment of the invention, the catalytic system consists of a catalytic entity selected from rare earth oxides or mixtures thereof. Rare earth (Ln) means the chemical elements selected from the group consisting of scandium, yttrium, and chemical elements of atomic number 57 to 71. Advantageously, the rare earths are chosen from cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), yttrium (Y), gadolinium (Gd) and samarium (Sm). ) and holmium (Ho), alone or as a mixture, preferably cerium, lanthanum, praseodymium, samarium, yttrium and neodymium, or mixtures thereof. According to the invention, the rare earth oxides are chosen from CeO ₂ ; Pr ₆ On rare earth oxides of formula Ln ₂ 0 ₃ wherein Ln represents lanthanum, neodymium, yttrium, gadolinium, samarium or holmium; alone or in mixture. Advantageously, the rare earth oxides are chosen from La ₂ 0 ₃ , Ce0 ₂ , Pr ₆ On, Nd ₂ 0 ₃ , Sm ₂ 0 ₃ , Y ₂ 0 ₃ , alone or as a mixture, preferably La ₂ 0 ₃ . By way of a particular mixture, mention may for example be made of CeO ₂ / Pr ₆ 0n.

Preferably, the rare earth oxide is La ₃ O ₃ .

Preferably, the rare earth oxide is CeO.

In general, the catalytic system according to the invention consists of a catalytic entity in solid form, thus allowing its use in a continuous process. The catalyst may in particular be in monolithic form (forming a single inert block, rigid, porous) or in extruded form.

The catalyst system may also comprise an inert support on which the catalytic entity is deposited. The catalytic system comprising a support according to the invention may be in extruded form, in the form of a coating having catalytic properties and based on rare earth oxide or mixture of rare earth oxides and optionally a binder. of known type on a substrate of metal or ceramic monolithic type. Advantageously, it is in extruded form. The extruded form advantageously makes it possible to shape the process of the invention in a continuous manner, which is not possible with a powder catalyst which would obstruct the various elements of the reactor.

For the process according to the invention, the term "catalytic extruded system" is understood to mean any catalytic system obtained by ejection under pressure of a paste through nozzles or dies of chosen shapes. The catalytic systems thus obtained may have various shapes, they may for example have cylindrical or semi-cylindrical, square, polygonal or even lobed sections, such as trilobes. The catalytic systems can be solid or hollow, they can have the form of monolith or honeycomb. These extruded catalyst systems may in particular be obtained by the process as described on pages 4 to 10 of the patent application WO98 / 24726. By inert support is meant a support which does not come into play, as a catalyst or as a reagent, in the transcarbonation reaction of the invention whatever the pH. Typically, the support is neutral, that is to say that it does not substantially modify the catalytic activity of the catalytic entity. The support may also be described as inactive insofar as it does not exhibit any catalytic activity for the reaction and does not modify the catalytic activity of the catalytic entity. The supports are chosen from extrudable and non-hydrolyzable supports or monolytic and non-hydrolyzable supports.

Preferably, the support may be chosen from extrudable and non-hydrolyzable metal oxides, clays, activated carbons (blacks), ceramic or metal monoliths. The support may for example be selected from titanium oxides, zirconium oxides, iron oxides; aluminum oxides, especially alundrum; silica-aluminas, for example clays; activated carbons; Kieselguhr.

It can also be corundrum, silica carbide, pumice stone.

Among the extrudable and non-hydrolysable metal oxides, mention may preferably be made of titanium oxides, zirconium oxides, iron oxides, aluminum oxides, preferably titanium oxides, zirconium oxides, neutral aluminas. More preferably, the support is chosen from titanium oxides, zirconium oxides, iron oxides, aluminum oxides, in particular neutral aluminas, active carbons, preferably titanium oxides, zirconium oxides, neutral aluminas, activated carbons.

The amount of catalytic entity on the support may be between 0.05 to 25 mol% relative to the number of moles of the support, preferably from 1 to 10 mol%. It should be noted that this value depends in particular on the nature of the support, its specific surface area, its porosity and the desired catalytic properties.

According to the invention, the catalytic system may in particular have a specific surface area of at least 1 m ² / g, preferably the specific surface area is between 1 and 150 m ² / g, more preferably between 3 and 100 m ² / boy Wut. The skilled person is at even to adjust this specific surface for example by calcination of the catalytic system.

According to the invention, the catalyst system can be doped with Lewis acid type metals, for example transition metals, alkaline earth metals and metalloids. Advantageously, these catalytic entities together with the dopants form solid solutions forming a unitary entity.

These metals may be selected from iron (Fe "and Fe ^1"), copper (Cu ¹ and Cu "), aluminum (Al ^111), titanium (Ti ^lv), boron (B ^111), the zinc (Zn ") and magnesium (Mg"). Preferably these metals are selected from the group consisting of iron (Fe "and Fe ¹ "), copper (Cu 'and Cu "), titanium (Ti ^lv ) and zinc (Zn ").

In the process of the invention, the relative percentage of metal relative to the catalytic entity may be between 0.01 and 10 mol%, preferably between 1 and 10 mol%, for example between 1 and 5%. in mole.

Advantageously, the catalyst systems of the invention are water-stable. For example, the catalysts of the invention may contain less than 5% by weight of water. This advantageously makes it possible to carry out the transcarbonation reaction in a medium containing water, for example in a medium containing less than 15% by weight of water, for example less than 5% by weight of water. Thus, and contrary to the method of the state of the art, it is not necessary to have a significant control of the amount of water in the reaction medium and it is not necessary to use exempt reagents. of water. This has particular advantages in terms of costs.

The catalyst according to the invention may, advantageously, be easily recovered after reaction by any method known to those skilled in the art, in particular by decantation or filtration.

The process according to the invention is carried out at atmospheric pressure or autogenous pressure. By autogenous pressure is meant the pressure inside the reactor which is due to the reagents used. In the case of the present invention, autogenous pressure is understood to mean a pressure of less than 1 MPa, preferably less than 0.5 MPa, preferably less than 0.3 MPa, for example less than 0.2 MPa. According to the invention, the method according to the invention is implemented at a temperature between 25 and 250 ° C, preferably between 25 and 200 ^, for example between 50 and 125 ^<€. Advantageously, the molar ratio polyol / alkyl carbonate or polyol / alkylene carbonate is between 1/30 and 1/1, preferably between 1/20 and 1/1, for example between 1/15 and 1 / 1.

Advantageously, the molar ratio polyol / alkyl carbonate or polyol / alkylene carbonate is between 1/30 and 1/10, preferably between 1/30 and 1/15 and the compound of formula (I) is a compound in which R represents (CH ₂ CH (OH) CH ₂ 0) _m CH ₂ R ² .

Advantageously, the molar ratio polyol / alkyl carbonate or polyol / alkylene carbonate is between 1/8 and 1/1, preferably between 1/5 and 1/1 and the compound of formula (I) is a compound in which R ¹ represents (CH ₂ CH (OH) CH ₂ 0) _n H.

Advantageously, the amount of catalytic entity is between 0.01 and 50 mol% relative to the number of moles of polyol, preferably between 1 and 25 mol%, preferably between 3 and 15 mol%.

The process according to the invention makes it possible to obtain the compound of formula (I) in good yields.

Advantageously, the process according to the invention is carried out in the absence of a solvent. The polyol may serve as a solvent for the reaction according to the invention.

The method according to the invention can be implemented continuously or discontinuously.

Advantageously, the process according to the invention is carried out continuously. According to the invention, the process may comprise a preliminary step of preparing the alkyl carbonate or the alkylene carbonate. This preliminary step is carried out by reaction between an alcohol or mixture of alcohols or a diol and C0 ₂ , in the presence of a catalytic system consisting of a catalytic entity selected from rare earth oxides and mixtures of oxides of rare earths and possibly a support.

The catalytic entity and the support are as defined for the transcarbonation process according to the invention. Advantageously, the molar ratio between alcohol or diol and CO ₂ is between 1 and 150 equivalents in moles, preferably between 1 and 100 equivalents.

According to the invention, the preliminary step of preparation of the alkyl carbonate or alkylene carbonate is carried out at autogenous pressure or at atmospheric pressure.

According to the invention, the preliminary step of preparing the alkyl carbonate or the alkylene carbonate is carried out at a temperature of between 25 and 250%, preferably between 25 and 200%, for example between 50 and 150%. ° C.

Advantageously, the amount of catalyst system is between 0.01 and 50% by weight relative to the weight of alcohol, mixture of alcohols or diol, preferably between 1 and 25% by weight, preferably between 3 and 15% by mass. According to the invention the alcohol corresponds to the formula R ² OH in which R ² represents:

a linear or branched C ₁ -C ₂₀ alkyl group;

a C ₅ to C ₅ aryl group optionally substituted with one or more substituents, in particular chosen from:

- alkyl to C _9, preferably C l -C _5;

- an aryl group of C ₅ -C _M, preferably C ₆ C, preferably

C ₆ to C ₁₀ , optionally substituted;

an alkyl-aryl group of formula -Q -Ar ¹ in which Q represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁹ represents a C ₆ -C ₆ , preferably C, aryl group; ₆ , optionally substituted; a polyalkoxy group of formula - (OCH ₂ CH ₂ ) q-OR ⁹ in which n represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5;

- alkyl to C _9, preferably C l -C _5;

an alkyl-aryl group of formula -Q ² -Ar ² in which Q ² represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ² represents a C ₆ -C ₆ aryl group, preferably C ₆ , optionally substituted; a polyalkoxy group of formula - (OCH ₂ CH ₂ ) q-OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5; or a heteroaryl group, preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur, optionally substituted by one or more substituents, in particular chosen from:

- alkyl to C _9, preferably C l -C _5;

a C ₅ to C 6, preferably C ₆ to C ₆ , aryl group, preferably

C ₆ -C ₁ 0, optionally substituted;

an alkyl-aryl group of formula -Q ³ -Ar ³ in which Q ³ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ³ represents a C ₆ -C ₆ aryl group, preferably C ₆ , optionally substituted; a polyalkoxy group of formula - (OCH ₂ CH ₂ ) _q -OR ⁹ in which q represents an integer between 2 and 5 and R ⁹ represents a C ₁ -C ₁₀ , preferably C ₁ -C ₅ , alkyl group;

- an alkoxy group -C _9, preferably C l -C _5;

- alkyl-aryl group of formula -Q ⁴ -Ar ⁴ wherein Q ⁴ represents an alkyl residue to C _9, preferably C, to C ₅ and Ar ⁴ represents an aryl group of C ₆ to C _M, of preferably C ₆ , optionally substituted.

Preferably, in the process of the invention R ¹² represents:

an alkyl-aryl group of formula -Q-Ar ¹ in which Q ¹ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ¹ represents an optionally substituted phenyl group, preferably methylphenyl or ethylphenyl;

- an alkoxy group at C _5, for example methoxy, ethoxy; or

a heteroaryl group, preferably comprising 5 to 10 members, preferably comprising 1 to 2 heteroatoms, in particular chosen from oxygen, nitrogen or sulfur, for example aniline, optionally substituted by one or more substituents, in particular chosen from :

- an alkoxy group at C _5, for example methoxy, ethoxy;

an alkyl-aryl group of formula -Q ⁴ -Ar ⁴ in which Q ⁴ represents a C ₁ -C ₉ , preferably C ₁ -C _5, alkyl residue and Ar ⁴ represents an optionally substituted phenyl group.

According to the invention the diol corresponds to the formula (V)

in which R ⁵ , R ⁶ , R ⁷ and R ⁸ identical or different are as defined above.

By continuous process is meant a process in which the reactants are continuously fed into the reactor and the products are withdrawn from the reaction medium continuously and then separated. The unreacted reagents can be reintroduced into the reaction medium or removed.

The invention will now be described by way of examples, these being given by way of illustration without being limiting.

EXAMPLE 1 Synthesis of Dicarboxyl Monocarbonate A 50 ml flask equipped with a condenser is charged with 7 g (42 mmol) of diglycerol (purity ≥ 80%) and 15.2 g (168 mmol) of dimethyl carbonate. The mixture is then brought to 90 ° C. and 0.7 g (2.1 mmol, 5 mol%) of lanthanide oxide are added. The reaction medium is heated at 120 ° C. for 24 hours. The solution is then filtered. After evaporation of the dimethyl carbonate, the product obtained is purified by flash column chromatography column (eluent (dichloromethane / MeOH: 9/1)) to give the diglycerol mono carbonate with an isolated yield of 81% and the dicarbonate of diglycerol with an isolated yield of 19%.

Example 2 Synthesis of Triglycerol Monocarbonate

In a 50 ml flask equipped with a condenser, 7 g (29 mmol) of triglycerol and 10.5 g (1 16 mmol) of dimethyl carbonate are introduced. The mixture is then heated to 90 ° C. and 0.47 g (1.5 mmol, 5 mol%) of lanthanide oxide are added. The reaction medium is heated at 120 ° C. for 24 hours. The solution is then filtered. After evaporation of the dimethyl carbonate, the product obtained is purified by flash column chromatography column (eluent (dichloromethane / MeOH: 9/1)) to give the triglycerol mono carbonate with an isolated yield of 80% and the dicarbonate of triglycerol with an isolated yield of 20%.

Example 3 Synthesis of Dicarboxyl Dicarbonate

In a 100 ml flask equipped with a condenser, 5 g (30 mmol) of diglycerol (purity≥80%) and 40.7 g (450 mmol) of dimethyl carbonate are introduced. The mixture is then heated to 90 ° C. and 0.5 g (1.5 mmol, 5 mol%) of lanthanide oxide are added. The reaction medium is heated at 120 ° C. for 48 hours. The solution is then filtered. After evaporation of the dimethyl carbonate, the product is crystallized in methanol to after filtration of the solution, obtain diglycerol dicarbonate with an isolated yield of 90%.

The following table groups the results of the various tests implemented.

The process according to the invention thus makes it possible to obtain polyglycerol (poly) carbonates in a simple and efficient manner.

Claims

claims

1. Process for the preparation by transcarbonation of a compound of formula (I),

(i) V

in which R ¹ represents:

a group (CH ₂ CH (OH) CH ₂ O) _n H; or

a group (CH ₂ CH (OH) CH ₂ 0) _m CH ₂ R ² ;

n is an integer of 1 to 10, preferably 1 to 5;

m is an integer of 0 to 10, preferably 0 to 5;

O

R ² representing A ^ ^

(he)

in which p represents an integer of 2 to 10.

2. Process according to claim 1, in which the alkyl carbonate is a compound of formula (III):

in which R ³ and R ⁴ , which are identical or different, represent:

a linear or branched C ₁ -C ₂₀ alkyl group;

an optionally substituted C ₅ to C ₆ aryl group;

an optionally substituted C ₅ -C ₆ cycloalkyl group; or a heteroaryl group, preferably comprising 5 to 10 members, optionally substituted;

- alkyl-aryl group of formula -Q ⁴ -Ar ⁴ wherein Q ⁴ represents an alkyl residue to C _9, and Ar ⁴ represents an aryl group of C ₆ to C _M, optionally substituted.

3. Process according to claims 1 or 2 for which the alkylene carbonate is a compound of formula (IV)

(IV)

in which

a hydrogen;

- a hydrocarbon group, to C ₉ linear, branched or cyclic, may include one or more heteroatoms, and may comprise one or more OH substituents;

a group of formula -CH ₂ -R ¹⁰ , in which R ¹⁰ represents a linear, branched or cyclic C ₁ -C ₉ hydrocarbon-based group which may comprise one or more heteroatoms, and which may comprise one or more OH substituents;

- a group of formula C (0) OR ^11, wherein R ¹¹ represents a hydrogen atom, an alkyl group -C _9;

an optionally substituted C ₅ -C ₆ cycloalkyl group;

an optionally substituted heteroaryl group;

an optionally substituted C ₆ to C _M aryl group;

an alkyl-aryl group of formula -Q ⁸ -Ar ⁸ in which Q ⁸ represents a C ₁ -C ₉ alkyl residue and Ar ⁸ represents an optionally substituted C ₆ -C ₆ aryl group;

4. Process according to claims 1 to 3 wherein R represents (CH ₂ CH (OH) CH ₂ 0) _n H.

5. Process according to claims 1 to 3 wherein R ¹ represents (CH ₂ CH (OH) CH ₂ 0) _m CH ₂ R ² .

6. Process according to claims 1 to 5, wherein the rare earth oxides have the formula Ln ₂ 0 ₃ , with Ln representing lanthanum, neodymium, yttrium, gadolinium, samarium or holmium; Ce0 ₂ or Pr ₆ On, alone or in mixture.

7. The method of claim 6, wherein the rare earth oxides are selected from La ₂ 0 _3, Ce0 _2, Pr ₆ is, Nd ₂ 0 _3, Sm ₂ 0 _3, Y ₂ 0 _3, alone or in admixture.

8. Method according to any one of claims 1 to 7, wherein the catalytic system comprises an inert support selected from extrudable and non-hydrolysable metal oxides, clays, activated carbons (blacks) and ceramic or metal monoliths.

9. Process according to claims 1 to 8, for which the catalytic system is extruded.

10. Process according to claims 1 to 4, wherein the molar ratio polyol / alkyl carbonate or polyol / alkylene carbonate is between 1/30 and 1/10, preferably between 1/30 and 1/15.

1 1. Process according to Claims 1 to 3 and 5, in which the molar ratio of polyol / alkyl carbonate or polyol / alkylene carbonate is between 1/8 and 1/1, preferably between 1/5 and 1/1.

12. Method according to one of claims 1 to 1 1, wherein the amount of catalytic entity is between 0.01 and 50 mol% relative to the number of moles of polyol, preferably between 1 and 25 mol%, preferably between 3 and 15 mol%.

13. The method of claims 1 to 12, implemented continuously.