Ring-opening or polycondensation polymerization process

Abstract

The invention relates to a process for preparing linear organopolysiloxanes (OL) by polymerization reaction from organopolysiloxanes (O) (cyclic and / or linear), using an AI catalytic system. More specifically, the process of the present invention makes it possible to obtain linear organopolysiloxanes (OL) of controlled molar mass with a very low residual level of cyclic organopolysiloxanes. This application also relates to the linear organopolysiloxane (OL) obtained according to the various embodiments of the process of the present invention described above.

Description

Title of the invention: Cycle-opening or polycondensation polymerization process Technical field

[0001] The invention relates to a process for preparing linear organopolysiloxanes OL by a polymerization reaction from organopolysiloxanes O (cyclic and / or linear), and using a catalytic system AI. More precisely, the process of the present invention makes it possible to obtain linear organopolysiloxanes OL of controlled molar mass with a very low level of residual cyclic organopolysiloxanes.

[0002] The invention also relates to the catalysts used in the AI ​​catalytic system which will be detailed in detail below. Technological background:

[0003] A major challenge for the silicone industry in the coming years is to industrially synthesize organopolysiloxanes with a very low or even zero residual cyclic content.

[0004] To date, the industrial synthesis of organopolysiloxanes by polycondensation or by ring-opening polymerization sees the formation of cyclic organopolysiloxanes such as octamethyltetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) or other unwanted cyclic organopolysiloxanes. In conventional industrial processes, ring-opening polymerization is preferred because it uses monomers that are easily synthesized, purifiable and therefore inexpensive. However, this method is also confronted with the presence of unwanted cyclic products which can amount to a content of between 6 and 15% relative to the total mass of linear organopolysiloxane obtained during the synthesis, which corresponds to thermodynamic equilibrium.Typically, this high cyclic product content requires energy-intensive process steps such as a high-temperature and / or reduced-pressure devolatilization step to separate these by-products from the resulting linear organopolysiloxane.

[0005] Thus, in the interests of economic and energy profitability, there is a need to develop new solutions to avoid or at least limit these long and costly separation stages.

[0006] Furthermore, cyclic silicones or organopolysiloxanes such as octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) are and will be subject to restrictions for their use. In addition to the fact that these cyclic compounds present environmental risks due to their non-biodegradability, they are also suspected of being endocrine disruptors and potentially can- cerigenic.

[0007] In this sense, in 2018 European regulations limited the content of D4 and D5 to a content of 0.1% by mass in rinse-off cosmetic products. This regulation will soon be adopted for other cosmetic products but also in other areas of application of silicones such as the electronics industry for example.

[0008] Therefore, there is a need to develop processes for providing linear organopolysiloxanes free from or at least having a low content of cyclic silicones. There is in particular an interest in providing a new catalytic system for implementing such a process. There is also an interest in being able to reliably control the molar mass of the products formed. This possibility makes it possible to increase the prospects for use and applications of such polymers obtained.

[0009] N-heterocyclic olefins (NHO) are highly polarized olefins due to their N-heterocyclic aromatic structure. They have a strong basic and nucleophilic character and are therefore interesting molecules as organic catalysts. Indeed, patent applications CN106750227 and CN109851765 describe the use of such catalysts for the ring-opening polymerization reaction of various cyclic monomers such as epoxides or cyclic esters.

[0010] Thus, one of the essential objectives of the invention is to carry out a polymerization reaction from organopolysiloxanes O (cyclic and / or linear), and using N-heterocyclic olefins. This invention will therefore aim to improve the preparation of organopolysiloxane by ring-opening polymerization reaction or by polycondensation, by means of a catalytic system which is more efficient than those used previously and which makes it possible to obtain higher yields of linear organopolysiloxane while limiting the formation of cyclic organopolysiloxanes by retroscission reaction. Summary of the invention

[0011] Surprisingly, the Applicant has developed a catalytic system which meets these expectations. Thus, the present invention relates to a process for preparing linear organopolysiloxanes OL by a polymerization reaction of at least one organopolysiloxane O, in the presence of a catalytic system AI comprising: -at least one catalyst A of formula (I): [Chem 1] ... . ^ï" h H , / x .P VN'^ X / R. 'X in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: - a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, R3same or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, -or the two R3 groups together with the atoms to which they are linked form a cyclic hydrocarbon group such as a cycloalkyl of 5 to 8 carbon atoms or a phenyl. and possibly at least one initiator I.

[0012] An objective of the present application is therefore to propose a process for preparing linear organopolysiloxanes OL by an organopolysiloxane polymerization reaction making it possible to control the molar mass of the final product with a yield of linear organopolysiloxanes OL greater than 90%, preferably greater than 95% and preferentially greater than 98%.

[0013] Another objective of the present application is to provide an AI catalytic system for the implementation of this process.

[0014] Another objective of the present application is to propose a simple and non-dangerous catalytic system compatible with the implementation of the process.

[0015] Still other objectives will appear on reading the description of the invention which follows. Description of the embodiments

[0016] Silicones, otherwise known as organopolysiloxanes, are polymeric materials comprising alternating silicon and oxygen atoms with various organic radicals bonded to the silicon.

[0017] In the context of the present invention, silicone, silicone product, silicone polymer or organopolysiloxane O means polymers comprising a siloxane backbone (Si-O-Si) having alternating silicon and oxygen atoms with various organic radicals bonded to silicon. These silicone polymers can be liquid or solid, depending on the molecular weight and the degree of polymerization.

[0018] For the purposes of the present invention, the term “reaction mixture” means all of the reactive chemical species present. By way of example, mention may be made of the catalyst(s) A, the initiator(s) I, the organopolysiloxane(s) O, and / or the chain blocker(s) C.

[0019] For the purposes of the present invention, the term AI catalytic system means a system consisting of: - catalyst A alone or, -the association of catalyst A and at least one initiator I which forms an active species capable of catalyzing the process of the present invention.

[0020] All the viscosities referred to in the present disclosure correspond to a dynamic viscosity quantity at 25°C known as “Newtonian”, i.e. the dynamic viscosity which is measured, in a manner known per se, with a Brookfield viscometer at a shear rate gradient sufficiently low so that the measured viscosity is independent of the rate gradient.

[0021] In the context of the present invention, the organopolysiloxane O present in the reaction mixture is chosen from: a linear organopolysiloxane alone or in mixtures, a cyclic organopolysiloxane alone or in mixtures, or even a mixture of one or more linear and cyclic organopolysiloxanes.

[0022] For the purposes of the present invention, the linear organopolysiloxane is represented by the following formula (II): [Chem 2], A: R' R5 in which, R1, identical or different, represents: - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, -an aryl group comprising from 6 to 18 carbon atoms, -a hydroxyl group, or R2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, q is an integer between 1 and 2000, preferably between 1 and 500, preferably between 1 and 200, more preferably between 1 and 50, and with the condition that at least one radical R2 is a hydroxyl group (OH).

[0023] For the purposes of the present invention, the linear organopolysiloxane is represented by the formula (II) in which, R1, identical or different, represents: - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, -an aryl group comprising from 6 to 18 carbon atoms, -a hydroxyl group, or R2 represent: -a hydroxyl group (OH), q is an integer between 1 and 500, preferably between 1 and 200, more preferably between 1 and 50.

[0024] According to one embodiment of the invention, the method of the present invention uses at least two organopolysiloxanes O chosen from the linear organopolysiloxanes mentioned above.

[0025] According to one embodiment of the invention, the cyclic organopolysiloxane is represented by the following formula (III): [Chem 3] in which, R, identical or different, is a radical representing an alkyl group of 1 to 6 carbon atoms, an alkenyl group of 2 to 6 carbon atoms, or an aryl group of 6 to 18 carbon atoms; and n represents a natural number between 1 and 2.

[0026] On peut notamment citer les organopolysiloxanes cycliques disponibles commercialement comme l’hexamethylcyclotrisiloxane (CAS 541-05-9), le 2-ethenyl-2’,4,4’,6,6’-pentamethylcyclotrisiloxane (CAS 18395-32-9), le 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane (CAS 3901-77-7), l’hexaphenylcyclotrisiloxane (CAS 512-63-0), le l,3,5-Trimethyl-l,3,5-tris(3,3,3-trifluoropropyl)cyclotrisiloxane (CAS 2374-14-3), le 2,2,4-Trimethyl-4,6,6-triphenyl-l,3,5,2,4,6-trioxatrisilinane, le l,3,5-Trimethyl-l,3,5-triphenylcyclotrisiloxane (CAS 546-45-2); le 2 4 6-trimethylcyclotrisiloxane (CAS 13269-39-1), le 3,5-trivinyl-l,3,5-trimethylcyclotrisiloxane (CAS 3901-77-7), le 2-Ethenyl-2,4,4,6,6-pentamethylcyclotrisiloxane (CAS 18395-32-9), le 2,4,6,8-Tetramethylcyclotetrasiloxane (CAS 2370-88-9), le 2,4,6,8-Tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (CAS 2554-06-5), le 2,4,6,8-Tetramethyl-2,4,6,8-tetraphenylcyclotetrasiloxane (CAS 77-63-4), l’octaphenylcyclotetrasiloxane (CAS 546-56-5).

[0027] Advantageously, the cyclic organopolysiloxane is hexamethylcyclotrisiloxane (CAS 541-05-9) or octamethylcyclotetrasiloxane (CAS 556-67-2)

[0028] According to one embodiment of the invention, the process of the present invention uses at least two cyclic organopolysiloxanes chosen from the following compounds: octamethylcyclotetrasiloxane (CAS 556-67-2); hexamethylcyclotrisiloxane (CAS 541-05-9) and 2,4,6-triethenyl-2,4,6-trimethylcyclotrisiloxane (CAS 3901-77-7).

[0029] As mentioned above, according to one embodiment of the invention, the method of the present invention uses a mixture of linear and cyclic organopolysiloxanes. These different organopolysiloxanes have been more fully defined above.

[0030] In the context of the present application, catalyst A is represented by the formula (IV): [Chem 4] in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group. R3same or different represent: -a hydrogen atom, —a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, -or the two R3 groups together with the atoms to which they are linked form a cyclic hydrocarbon group such as a cycloalkyl of 5 to 8 carbon atoms or a phenyl.

[0031] In the context of the present application, catalyst A is represented by the formula (V): [Chem 5] in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: -a hydrogen atom, —a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group.

[0032] In the context of the present application, catalyst A is represented by the formula (VI): [Chem 6] . .fV UH \ / in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: —a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group.

[0033] In the context of the present application, catalyst A is represented by the formula (VII): [Chem 7] in which: R identical or different represent: -a hydrogen atom, —a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group.

[0034] According to one embodiment, the process of the invention is characterized in that the catalyst A is diluted in an alcohol solution; preferably ethanol.

[0035] This alcohol solution makes it possible to guarantee the stability of catalyst A during its storage in the open air for long periods. Long periods are understood to mean durations of one or more weeks but also ranging from one to several months.

[0036] This embodiment of the invention illustrates the robustness of the method of the present invention.

[0037] According to one embodiment, the process of the invention is characterized in that the molar quantity of catalyst A relative to the organopolysiloxane O is from 0.005% to 2%, preferably from 0.01 to 2%, preferentially from 0.05 to 1%, and even more preferentially from 0.1 to 0.5%.

[0038] For the purposes of the present invention, the initiator I is chosen from water, alcohols and their derivatives or their mixtures.

[0039] According to one embodiment of the present invention, the initiator I is chosen from alcohols having a pKa of 10 to 16, preferably a pKa of 12 to 16, preferentially a pKa of 14 to 16.

[0040] According to one embodiment of the invention, the initiator I is chosen from water or the compounds of formula (VIII): [Chem 8] HQ----------Y-------------R | Formula VIII R in which: Y represents a carbon or silicon atom, R is the same or different and represents: -a hydrogen atom -an alkyl group comprising from 1 to 12 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, when said radical R may be substituted or not by an alkyl group comprising from 1 to 12 carbon atoms, an alkenyl group comprising from 2 to 6 carbon atoms, a cycloalkyl group comprising from 5 to 8 carbon atoms, an aryl group comprising from 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

[0041] According to a preferred embodiment of the invention, the initiator I is represented by the compounds of formula (VIII) above in which: Y represents a carbon atom, R is the same or different and represents: -a hydrogen atom -an alkyl group comprising from 1 to 12 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, when said radical R may be substituted or not by an alkyl group comprising from 1 to 12 carbon atoms, an alkenyl group comprising from 2 to 6 carbon atoms, a cycloalkyl group comprising from 5 to 8 carbon atoms, an aryl group comprising from 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

[0042] According to one embodiment, the initiator I is an alcohol chosen from primary alcohols or secondary alcohols. Preferably, the initiator I is an alcohol chosen from primary alcohols.

[0043] According to one embodiment, the initiator I is an alcohol chosen from saturated or unsaturated polyols having 2 to 6 hydroxyl groups. By way of example, the following polyols may be mentioned such as glycerol, pentaerythritol, sorbitol or 1,4 butanediol.

[0044] According to one embodiment, the initiator I is an alcohol having a pKa of 10 to 16, preferably a pKa of 12 to 16, preferentially a pKa of 14 to 16.

[0045] According to one embodiment, the initiator I is an alcohol chosen from: methanol (CAS 67-56-1), ethanol (CAS 64-17-5), propanol (CAS 71-23-8), isopropanol (CAS 67-63-0), butanol (CAS 71-36-3), 2-methylpropan-2-ol (CAS 75-65-0), allyl alcohol (CAS 107-18-6), benzyl alcohol (CAS 100-51-6), 3-buten-1-ol (627-27-0), long-chain alkyl alcohols such as undecanol (CAS 112-42-5) or dodecanol (CAS 27342-88-7).

[0046] Preferably, the initiator I is benzyl alcohol (CAS 100-51-6).

[0047] According to another embodiment of the invention, the initiator I is water.

[0048] In one embodiment, the process of the invention is characterized in that the molar ratio of initiator I relative to catalyst A is from 0 to 20, preferably from 0 to 10, preferably from 0 to 5, preferentially from 0 to 2.

[0049] In one embodiment, the process of the invention is characterized in that the molar quantity of initiator I relative to the organopolysiloxane O introduced is from 0.005% to 10%, preferably from 0.01% to 5%, preferentially from 0.05% to 2.5%, and even more preferentially from 0.1% to 1%.

[0050] According to one embodiment, the method of the invention uses an initiator I represented by the formula (IX): [Chem 9] HO--Si—R | Formula IX in which: R is the same or different and represents: -an alkyl group comprising from 1 to 12 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, said radical R may be substituted or not by an alkyl group comprising from 1 to 12 carbon atoms, an alkenyl group comprising from 2 to 6 carbon atoms, a cycloalkyl group comprising from 5 to 8 carbon atoms, an aryl group comprising from 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen.

[0051] Preferably, the process of the present invention uses an initiator I chosen from trimethylsilanol (CAS 1066-40-6) or triethylsilanol (CAS 597-52-4).

[0052] In one embodiment of the invention, the polymerization reaction of at least one organopolysiloxane O further comprises at least one chain blocker C.

[0053] Thus, according to one embodiment of the invention, the method uses a catalytic system AI and a chain blocker C.

[0054] More specifically, according to one embodiment of the invention, the process uses a catalyst A and a chain blocker C.

[0055] Alternatively, according to one embodiment of the invention, the process uses a catalyst A, an initiator I and a chain blocker C. According to one embodiment of the invention, the chain blocker C is represented by the formula (X): [Chem 10] in which, R1, identical or different, represents CH3 or phenyl, preferably CH3; R2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, optionally substituted by at least one heteroatom O, N, S or a halide such as a fluorine atom, for example 1 to 10 fluorine atoms, for example (Ci-C5)alkyl-CF3, the alkyl being linear or branched, - a C5-C10 cycloalkyl group, optionally substituted, - a C6-C18 aryl group, optionally substituted, or -a hydrogen atom; and q is an integer between 1 and 50, preferably between 1 and 20, more preferably between 1 and 10.

[0056] Particularly preferably, the chain blocker C of the invention is represented by the formula (X), in which: R1, identical, represents CH3 R2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, - a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, - a C6-C18 aryl group, optionally substituted, or -a hydrogen atom. and q is an integer between 1 and 20, preferably between 1 and 10, more preferably between 1 and 5.

[0057] Other blockers having a siloxane function according to the invention are described in the work Chemistry and Technology of Silicones, published in 1968 by Académie Press, on page 264. The chain blocker C can be in a solvent. This is particularly advantageous in order to solubilize it in the reaction mixture. The solvent can in particular be an apolar solvent such as an organic solvent of the alkane or aromatic hydrocarbon type. Preferably, the solvent is chosen from n-hexane, n-heptane, n-decane, n-dodecane, isododecane, EXXSOL D60, xylene, toluene and mixtures thereof.

[0058] In one embodiment, the process of the invention is characterized in that the molar ratio of chain blocker C relative to catalyst A is from 0 to 30, preferably from 0 to 20, and preferentially from 0 to 10. According to one embodiment of the invention, the linear organopolysiloxane OL may be a compound of formula (XI): [Chem 11] in which, R, identical or different, represents: -an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably methyl, - an aryl group comprising from 6 to 10 carbon atoms, preferably phenyl, R1, identical or different, represents: -an alkyl group comprising from 1 to 5 carbon atoms -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), -a hydrogen atom; - a C6-C18 aryl group, preferably phenyl, R2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), -a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, optionally substituted by at least one he- teratom O, N, S or a halide such as a fluorine atom, for example 1 to 10 fluorine atoms, for example (Ci-C5)alkyl-CF3, the alkyl being linear or branched, -a C5-C10 cycloalkyl group, optionally substituted, -an optionally substituted C6-C aryl group, -a hydrogen atom or -a group (O-R3) with R3 representing: an alkyl group comprising from 1 to 15 carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, preferably OCH3 or OC2H5, an alkenyl group comprising from 2 to 15 carbon atoms, preferably from 2 to 10 carbon atoms, a C6-C18 aryl group or alkylaryl such as a benzyl group q is an integer between 0 and 50, preferably between 0 and 20, more preferably between 0 and 10; preferably q = 0 n2 represents an integer between 10 and 10,000, preferably between 10 and 5,000, preferably between 10 and 1,000, more preferably between 10 and 500; m2 represents an integer between 0 and 5000, preferably between 0 and 1000, more preferably between 0 and 100.

[0059] According to a preferred embodiment of the invention, the linear organopolysiloxane OL is a compound of formula (XI): in which, R, identical or different, represents CH3 or phenyl, preferably CH3; R1, identical or different, represents: -an alkyl group comprising from 1 to 5 carbon atoms -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, - a C6-C18 aryl group, preferably phenyl, -a hydrogen atom; R2 identical or different, represents: -an alkyl group comprising from 1 to 6 carbon atoms -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), -a C6-C18 aryl group, -a hydrogen atom; -a group (O-R3) with R3 representing: an alkyl group comprising from 1 to 10 carbon atoms, an alkenyl group comprising from 2 to 10 carbon atoms, or a benzyl group q is an integer between 0 and 50, preferably between 0 and 20, more preferably between 0 and 10; preferably q = 0 n2 represents an integer between 10 and 10,000, preferably between 10 and 5,000, of preferably between 10 and 1,000, more preferably between 10 and 500; m2 represents an integer between 0 and 5000, preferably between 0 and 1000, more preferably between 0 and 100.

[0060] According to a particularly preferred embodiment of the invention, the linear organopolysiloxane OL of the invention is a compound of formula (XI) in which, R, identical or different, represents CH3 or phenyl, preferably CH3, R1, identical or different, represents CH3, phenyl or vinyl; R2 identical or different, represents: -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), - a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, - a C6-C18 aryl group, optionally substituted, or -a hydrogen atom; -a group (O-R3) with R3 representing: an alkyl group comprising from 1 to 10 carbon atoms, an alkenyl group comprising from 2 to 10 carbon atoms, or a benzyl group q is equal to 0; n2 represents an integer between 10 and 10,000, preferably between 10 and 5,000, preferably between 10 and 1,000, more preferably between 10 and 500; m2 represents an integer between 0 and 5000, preferably between 0 and 1000, more preferably between 0 and 100.

[0061] According to a particularly preferred embodiment of the invention, the linear organopolysiloxane OL of the invention is a compound of formula (XII) in which: R, identical or different, represents CH3 or phenyl, preferably CH3, R1, identical or different, represents CH3, phenyl or vinyl; R2 identical, represent: - a linear or branched alkyl group comprising from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, -a hydroxyl group (OH), -a group (O-R3) with R3 representing: an alkyl group comprising from 1 to 10 carbon atoms, an alkenyl group comprising from 2 to 10 carbon atoms, or a benzyl group q is equal to 0; n2 represents an integer between 10 and 5,000, preferably between 10 and 1,000, more preferably between 10 and 500; m2 represents an integer between 0 and 1000, preferably between 0 and 500, more preferably between 0 and 100.

[0062] The linear organopolysiloxane OL of the invention is characterized in that its degree of polymerization is strictly greater than that of the organopolysiloxane O introduced into the reaction mixture.

[0063] According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its degree of polymerization is at least twice as high, at least three times as high or even at least five times as high as that of the organopolysiloxane O introduced into the reaction mixture.

[0064] For the purposes of the present invention, the mass-average molar mass and the number-average molar mass, denoted respectively Mw and Mn, of the various linear organopo-lysiloxanes OL can be determined by size exclusion chromatography (SEC) in the presence of polystyrene standards in a solvent such as toluene at 35°C.

[0065] According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its number-average molar mass Mn is between 500 and 1,000,000 g / mol, preferably between 500 and 500,000 g / mol, preferentially between 500 and 100,000 g / mol and even more preferentially between 500 and 50,000 g / mol.

[0066] According to one embodiment of the process of the invention, the linear organopolysiloxane OL of the invention is characterized in that its dynamic viscosity is between 100 and 1,000,000 mPa.s at 25°C, preferably between 100 and 500,000 mPa.s at 25°C, even more preferably between 100 and 100,000 mPa.s at 25°C.

[0067] In the context of the present application, the mass percentage or the weight percentage of cyclic organopolysiloxanes (such as D4) of the products obtained according to the process of the present invention can be measured via the quantitative 29Si NMR spectra. Alternatively, the mass percentage or the weight percentage of D4 of the products obtained according to the process of the present invention could be measured via the chromatograms resulting from a size exclusion chromatography (SEC) analysis.

[0068] Hereinafter, the product resulting from the reaction is the sum of the linear organopolysiloxane OL and the organopolysiloxane OC resulting from the process of the present invention.

[0069] In one embodiment, the method according to the invention is characterized in that the content of cyclic organopolysiloxanes OC is less than 4%, preferably less than or equal to 2%, preferentially less than or equal to 1%, even more preferentially less than or equal to 0.5% relative to the total mass of product resulting from the reaction.

[0070] In one embodiment, the process according to the invention is characterized in that the octamethylcyclotetrasiloxane (D4) content is less than or equal to 4%, preferably less than or equal to 2%, preferentially less than or equal to 1%, even more preferentially less than or equal to 0.5% relative to the total mass of product resulting from the reaction.

[0071] In one embodiment, the method according to the invention is implemented in an apolar solvent. The solvent may in particular be an organic solvent of the alkane, aromatic hydrocarbon or alcohol type such as ethanol.

[0072] Preferably, the solvent is chosen from n-hexane, n-heptane, n-decane, n-dodecane, cyclohexane, isododecane, EXXSOL D60, xylene, toluene and mixtures thereof.

[0073] According to one embodiment of the invention, the quantity of solvent used in the process of the invention is the minimum quantity necessary to solubilize catalyst A in the reaction mixture. The catalyst can thus be solubilized in ethanol or toluene.

[0074] Advantageously, and preferably, the reaction is carried out at a temperature between 50°C and 250°C, preferably between 70 and 170°C, more preferably between 80 and 150°C.

[0075] According to one embodiment, the duration of the reaction is between 1h and 72h, preferably between 8h and 72h, more preferably between 18h and 72h. Those skilled in the art will know how to adapt these parameters according to the nature of the reactors and the species used.

[0076] The present application also relates to the linear organopolysiloxane OL obtained according to the different embodiments of the process of the present invention described above. It also relates to a silicone composition comprising the organopolysiloxane OL obtained according to the different embodiments of the process of the present invention described above.

[0077] The present application also relates to a composition for implementing the method of the present invention comprising: - at least one cyclic organopolysiloxane O as defined previously, - a catalytic system AI as defined previously, and optionally a chain blocker C as defined previously.

[0078] The present application also relates to the use of the organopolysiloxanes OL obtained according to the process of the present invention as an ingredient which can be directly used in various silicone formulations useful in fields such as cosmetics, household cleaning products, automobiles, energy.

[0079] The present application also relates to the use of catalyst A for the implementing a ring-opening or polycondensation polymerization reaction in the presence of organopolysiloxanes O (cyclic and / or linear). It also relates to the use of the AI ​​catalytic system for implementing a ring-opening or polycondensation polymerization reaction in the presence of organopolysiloxanes O (cyclic and / or linear). Examples

[0080] Organopolysiloxanes used in the examples:

[0081] Cyclic organopolysiloxane Oi: octamethylcyclotetrasiloxane (CAS 556-67-2)

[0082] Linear organopolysiloxane O2: [Chem 15] Catalysts A used in the examples:

[0083] Catalyst Ai: [Chem 16] " "M 'N '' " Acompl Catalyst: [Chem 19]

[0084] Initiators implemented in the examples: Initiator Ii: benzyl alcohol (CAS 100-51-6)

[0085] Chain blockers implemented in the examples:

[0086] Chain blocker Ci: divinyltetramethyldisiloxane (CAS 2627-95-4).

[0087] C2 chain blocker: hexamethyldisiloxane (CAS 107-46-0)

[0088] In the context of the examples described below, the residual mass percentages of cyclic organopolysiloxanes OC and the mass percentages of linear organopolysiloxane OL obtained according to the process of the present invention are measured by size exclusion chromatography (SEC) in the presence of polystyrene standards in a solvent such as toluene at 35°C. Similarly, the number-average molar mass noted Mn of the different linear organopolysiloxanes according to the

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] present invention OL is determined by the same size exclusion chromatography (SEC) method. In the context of the examples described below, the mass percentage of residual cyclic organopolysiloxanes is referred to as the mass percentage of cyclic organopolysiloxane at the end of the process implemented according to the present invention. Example 1: Synthesis of the catalysts of the present invention as Ax: In a first step, the precursor a mentioned in the reaction scheme below was obtained by the reaction of iodomethane (3.7 mL, 59.3 mmol, 1.5 eq.) and 1,2-dimethylimidazole (3.8 g, 39.5 mmol, 1 eq.) which were added in a solvent such as acetonitrile at room temperature. After stirring for 1 h, the precipitated product ax was collected by filtration and washed with Et2O (2 x 10 mL). After drying under vacuum, the product ax was obtained as a white solid (8.9 g, 95%): [Chem. 20] In a second step, the product synthesized in the previous step (2 g, 8.5 mmol, 1 eq.) was added to a suspension of potassium hydride (0.67 g, 17 mmol, 2 eq.) in Et2O (30 mL). The reaction medium, placed under argon flow, was stirred at room temperature for 2 days. After filtration and vacuum drying of the resulting solution, the product Ai is obtained as a white solid (0.72 g, 78%). [Chem.21] Example 2: General protocol for implementing the method of the present invention: The AI ​​catalytic system is formed by the association of catalyst A (e.g., Ai) (leq, 0.025 mmol) and 0 to n equivalents of initiator I (e.g., Ii). The different tables below indicate the different molar ratios 1 / A. This freshly formed AI catalyst system is mixed in a solution containing an organopolysiloxane Oi or O2 (5.07 mmol). The content of catalyst A is 0.5 mol% relative to the organopolysiloxane O. Optionally, a blocker chains such as C1 or C2 are added to the reaction mixture. The reaction mixture is then heated to a temperature of 80°C for a time indicated in each of the examples of the present invention.

[0098] Example 3: Implementation of the method of the present invention in the presence of organopolysiloxane Oi:

[0099] In the context of this example, the general protocol of Example 2 was implemented. In this example, the organopolysiloxane Oi (CAS 556-67-2) was used. The initiator is Ii and the molar ratio I / A is equal to 1. The reaction mixture was heated at 80°C for a period of 48 hours for tests 1 and 2 and 72 hours for test 3. The table below describes the different catalysts used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 1] Test number Catalyst A Mn of OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 A ■^compl 66,094 94.2 5.8 2 Ai 113,969 98.8 1.2 3 Ai 117,200 99.2 0.8%

[0100] It can be noted that in the presence of the catalysts described according to the process of the invention as Ai, a product OL is obtained having a residual cyclic organopolysiloxane content lower than that of the comparative catalyst Acompl.

[0101] Example 4: Implementation of the method of the present invention with different I / A ratios:

[0102] In this example, the general protocol of Example 2 was implemented. In this example, organopolysiloxane Oi (CAS 556-67-2), initiator L and catalyst Aï were used.

[0103] The various tests listed in the example below were carried out at a temperature of 80°C for a period of 72 hours. The table below indicates the various initiators I used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 2] Test number Molar ratio 1 / A Mn of OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 0.5 117 200 99.2 0.8 2 0.1 186 600 99.4 0.6 3 0.05 297 100 98.4 1.6

[0104] It can be observed that the method of the present invention is versatile and allows satisfactory results to be obtained with different I / A ratios as set out in the table above.

[0105] Example 5: Implementation of the method of the present invention without initiator:

[0106] In the context of this example, the general protocol of Example 2 has been implemented work. In this example, organopolysiloxane Oi (CAS 556-67-2), catalyst Ai and chain blocker Ci were used. In these tests, the reaction mixture was heated to a temperature of 80°C for a period of 72 hours.

[0107] The table below mentions the molar ratio of the chain blocker used in relation to the molar quantity of catalyst A used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 3] Test number Initiator I Molar ratio C / A Mn of the OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 - 1 41,800 99.7 0.3 2 2 29,300 99.7 0.3 3 10 7,400 99.9 0.1

[0108] Even without initiator, the process of the present invention makes it possible to obtain a linear organopolysiloxane OL with a very low mass percentage of residual cyclic organopolysiloxane OC.

[0109] These tests were repeated under the same operating conditions with the C2 chain blocker.

[0110] The table below mentions the molar ratio of the chain blocker C2 used in relation to the molar quantity of catalyst A used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 4] Test number Initiator I Molar ratio C / A Mn of the OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 - 1 40 700 98.0 2 2 2 35 300 98 2 3 10 13 400 99.7 0.3

[0111] Under these operating conditions, the process of the present invention leads to the production of linear organopolysiloxane OL having a very low mass percentage of residual cyclic organopolysiloxane OC.

[0112] Alternatively, this method can also be carried out for a period of 24 hours at a temperature of 150°C as set out in the table below.

[0113] This table mentions the molar ratio of the chain blocker Ci used in relation to the molar quantity of catalyst Ai used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 5] Test number Initiator I Molar ratio C / A Mn of the OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 0 118 600 96.7 3.3 2 1 27 500 99.9 0.1 3 2 25 600 99.9 0.1 4 10 5 060 99.9 0.1

[0114] The results obtained in the table above confirm the versatility of the implementation of the method of the present invention.

[0115] Example 6: Stability of the catalyst in an ethanol solution:

[0116] Catalyst Ai (80 mg) was placed in an ethanol solution (ImL) and left in the open air for a period of one month. Before use, the ethanol is removed under vacuum. Once this step has been completed, the general protocol of Example 2 is repeated in the presence of Oi at a temperature of 80°C for 62 hours.

[0117] The table below mentions the molar ratio of the chain blocker Ci used in relation to the molar quantity of catalyst A used as well as the characteristics of the product OL obtained according to the process of the invention. [Tableauxô] Test number Initiator I Molar ratio C / A Mn of the OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 - 5 11 300 98.5 1.5 2 10 4 800 99.5 0.3

[0118] The results in the table above confirm the one-month stability of the catalyst in an ethanol solution. These satisfactory results confirm the robustness of the catalytic system implemented in the context of the present invention.

[0119] Example 7: Polycondensation reaction: process of the present invention carried out in the presence of organopolysiloxane O2 without initiator:

[0120] In this example, catalyst Ai (0.5mol%, 0.0137 mmol) is mixed in a solution containing an organopolysiloxane O2 (2.73 mmol).

[0121] Optionally, a chain blocker such as Ci is added to the reaction mixture as set forth in the table below.

[0122] The reaction mixture was heated to a temperature of 80°C for a period of 48 hours. The table below shows the molar ratio of the chain blocker Ci used relative to the molar quantity of catalyst A used as well as the characteristics of the product OL obtained according to the process of the invention. [Tables 7] Test number Initiator I Molar ratio C / A Mn of the OL product (g / mol) Mass percentage of OL product (%) Mass percentage of residual OC (%) 1 0 145 530 99.1 0.9 2 1 80 760 99.3 0.7 3 2 65 970 99.4 0.6 4 5 27 740 99.6 0.4 5 10 21 840 99.4 0.6

[0123] As indicated in the table above, this example demonstrates that the process of the present invention leads to the obtaining of very satisfactory results for polycondensation reactions.

Claims

Claims

1. Process for the preparation of linear organopolysiloxanes OL by a polymerization reaction of at least one organopolysiloxane O, in the presence of a catalytic system AI comprising: -at least one catalyst A of formula (I): [Chem 23] in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a cycloalkyl group comprising 5 to 8 carbon atoms, -a benzyl or phenyl group, R2 identical or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, R3same or different represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group, -or the two R3 groups together with the atoms to which they are linked form a cyclic hydrocarbon group such as a cycloalkyl of 5 to 8 carbon atoms or a phenyl. and possibly at least one initiator I.

2.

3. Process according to claim 1 in which the organopolysiloxane O is chosen from: a linear organopolysiloxane alone or in mixtures, a cyclic organopolysiloxane alone or in mixtures, or a mixture of one or more linear and cyclic organopolysiloxanes. Process according to claim 1 or 2, in which the catalyst A is represented by the following formula (VI): [Chem 24] in which: Identical or different Ri represent: -a hydrogen atom, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 6 carbon atoms, - a benzyl group or a phenyl, R2 identical or different represent: - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms, -an alkenyl group comprising from 2 to 12 carbon atoms, -a benzyl or phenyl group.

4. Process according to any one of the preceding claims, in which the molar quantity of catalyst A relative to the organopolysiloxane O is from 0.005% to 2%, preferably from 0.01 to 2%, preferentially from 0.05 to 1%, and even more preferentially from 0.1 to 0.5%.

5. A process according to any one of the preceding claims, wherein the initiator I is selected from water or compounds of formula (VIII): [Chem 25] R HQ— -j—R | Formula VIII R in which: Y represents a carbon or silicon atom, R is identical or different and represents: - a hydrogen atom - an alkyl group comprising from 1 to 12 carbon atoms, - a cycloalkyl group comprising from 5 to 8 carbon atoms, - an alkenyl group comprising from 2 to 12 carbon atoms, - a benzyl group or a phenyl, when said radical R may be substituted or not by an alkyl group comprising from 1 to 12 carbon atoms, an alkenyl group comprising from 2 to 6 carbon atoms, a cycloalkyl group comprising from 5 to 8 carbon atoms, an aryl group comprising from 6 to 18 carbon atoms or a heteroatom such as oxygen, sulfur or nitrogen. ^Claim 6] Process according to any one of the preceding claims, in which the molar ratio of initiator I relative to catalyst A is from 0 to 20, preferably from 0 to 10, preferably from 0 to 5, preferentially from 0 to 2.^Claim 7] Process according to any one of the preceding claims, in which during the polymerization reaction of at least one organopolysiloxane O at least one chain blocker C represented by the formula (X) is added: [Chem 26] R1 R s4-0-----Si 4- R; 1 ir 4 1 < 5. Formula XR' R1 in which, R1 identical or different, represents CH3 or phenyl, preferably CH3 R2 identical or different, represents: - an alkenyl group comprising from 2 to 6 carbon atoms, preferably vinyl, - a linear or branched alkyl group comprising from 1 to 12 carbon atoms, preferably from 1 to 5 carbon atoms, optionally substituted by at least one heteroatom O, N, S or a halide such as a fluorine atom, for example 1 to 10 fluorine atoms, for example (Ci -. C5)alkyl-CF3, the alkyl being linear or branched, -a C5-C10 cycloalkyl group, optionally substituted, -a C6-C18 aryl group, optionally substituted, or -a hydrogen atom; and q is an integer between 1 and 50, preferably between 1 and 20, more preferably between 1 and 10.

8. A process according to any one of the preceding claims, wherein the molar ratio of chain blocker C to catalyst A is from 0 to 30, preferably from 0 to 20, and most preferably from 0 to 10.

9. Silicone composition comprising the linear organopolysiloxane OL obtained according to one of the preceding claims 1 to 8.

10. Composition for implementing the method defined according to claims 1 to 7 comprising: - at least one cyclic organopolysiloxane O as defined in claim 1 or 2, - a catalytic system AI as defined in claim 1, 3, 4, 5 or 6 and optionally a chain blocker C as defined in claim 7 or 8.