WO2018109395A1

WO2018109395A1 - Silane bearing an anthracenyl group

Info

Publication number: WO2018109395A1
Application number: PCT/FR2017/053564
Authority: WO
Inventors: Rachid Matmour; Benoit SCHNELL; Sergey Ivanov
Original assignee: Compagnie Generale Des Etablissements Michelin
Priority date: 2016-12-15
Filing date: 2017-12-14
Publication date: 2018-06-21
Also published as: FR3060564A1

Abstract

The present invention relates to a silane compound bearing a substituted or non-substituted anthracenyl group, of formula (Ia) or (Ib), wherein: each R, which may be identical or different, represents a hydrocarbon chain that can be substituted or interrupted by one or more heteroatoms; Y represents a hydrocarbon chain; and n is an integer between 1 and 3.

Description

Silane carrying an anthracenyl group

The field of the present invention is that of the compounds intended to react with a diene polymer to graft on the polymer chain pendant carbon-carbon double bonds in the form of anthracenyl unit.

The diene polymer synthesis bearing pendant conjugated carbon-carbon double bonds may be carried out by the copolymerization of a 1,3-diene such as 1,3-butadiene or isoprene and a triene such as 1, 3,5-hexatriene or allocimene. For example, it is possible to refer to document EP 2 423 239. However, three aspects make it difficult to synthesize diene polymers bearing pendant conjugated double bonds by copolymerization of a 1,3-diene and a triene, and this is of as much as the rate of pendant conjugated double bonds becomes relatively high in the polymer chain.

The first aspect is that only the insertion of the triene by a 1,2 addition in the polymer chain during the polymerization leads to the formation of two pendant conjugated double bonds, while the triene can also be inserted by an addition. , 4 and a 1.6 addition which lead respectively to a pendant double bond and two conjugated double bonds in the chain, as shown in Figure 1 in the case of the polymerization of hexatriene, P * representing a polymer chain in growth. As a result, the rate of pendant conjugated double bonds may be limited.

The second aspect is related to the high reactivity of the sites propagating with respect to the pendant conjugated double bonds and their coexistence in the polymerization medium. The reaction of the sites propagating on the pendant conjugated double bonds leads not only to the disappearance of a part of the pendant conjugated double bonds but also to a widening of the molecular distribution of the polymer, as shown in diagram 2. This secondary reaction takes magnitude when the level of pendant conjugated double bonds in the polymer chain increases and when the reaction medium is depleted in monomers. To minimize this side reaction, it is then preferable to minimize the formation of pendant conjugated double bonds or the conversion rate.

The third aspect results from the relative reactivity coefficients of triene and diene, which are generally unfavorable vis-à-vis the incorporation of triene in the polymer chain. To expect a better incorporation of the triene into the copolymer chain, it is then preferable to carry out the polymerization in a semi-continuous process with a triene-rich monomer charge in the polymerization medium and a controlled diene feed, which complicates the synthesis. of the polymer. 

These aspects are particularly illustrated in document EP 2 423 239 in the copolymerization of allocimene and 1,3-butadiene, since for a monomeric filler containing 1.28 mol% of allocimene, the copolymer contains only 0.19 mol% of The unit allocimene and has a polydispersity index of 1.14 against 1.01 for a polymerization conducted in the absence of allocimene. It is therefore a concern to find another way to access such copolymers.

The Applicants have discovered novel compounds which thus provide access to the synthesis of diene polymers bearing pendent carbon-carbon conjugate double bonds, especially outside the chain ends of the polymer, without the aforementioned drawbacks. These are silanes bearing anthracene units which are intended to be grafted onto a diene polymer by a hydrosilylation reaction.

Thus, a first subject of the invention concerns a compound of formula (Ia) or (Ib)

(la) (Ib) in which

the symbols R, which may be identical or different, each represent a hydrocarbon-based chain which may be substituted or interrupted by one or more heteroatoms,

the symbol Y represents a hydrocarbon chain,

n being an integer from 1 to 3.

Another subject of the invention relates to a process for the preparation of these silane compounds from new compounds, halosilanes.

The invention also relates to those halosilanes which are different from the silanes according to the invention by replacing the SiH function with a SiX function, X being a halogen.

The invention also relates to the use of the compound according to the invention of formula (Ia) or (Ib) as modifying agent for a polymer having at least one carbon-carbon double bond. I. DETAILED DESCRIPTION OF THE INVENTION

In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are% by weight. The abbreviation "pce" means parts by weight per hundred parts of elastomer (of the total elastomers if several elastomers are present).

On the other hand, any range of values designated by the expression "between a and b" represents the range of values greater than "a" and less than "b" (i.e., terminals a and b excluded). while any range of values designated by the term "from a to b" means the range of values from "a" to "b" (i.e. including the strict limits a and b).

The compounds mentioned in the description may be of fossil origin or biobased. In the latter case, they can be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass.

The compound according to the invention and intended to be grafted onto a diene polymer by hydrosilylation reaction has the essential characteristic of being of formula (Ia) or (Ib)

(la) (Ib) in which

the symbol Y represents a hydrocarbon chain,

n being an integer from 1 to 3.

The compound according to the invention and intended to be grafted onto a diene polymer by hydrosilylation reaction is referred to herein as the compound intended to be grafted. According to one embodiment of the invention, the symbols R of formula (Ia) or (Ib) represent an alkyl. As alkyl, alkyls having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms, in this case methyl or ethyl, are particularly suitable. Preferably, the symbols R of formula (Ia) or (Ib) are identical. Better, they each represent a methyl or ethyl.

According to one embodiment of the invention, the symbol Y represents an alkanediyl group. Particularly suitable alkanediyl groups are those having 1 to 6 carbon atoms, preferably ethane-1,2-diyl or propane-1,3-diyl.

The anthracene motif can be substituted by the group containing Y both in position 1, in 2 or 9 according to the nomenclature conventionally used for anthracene and recalled by the following representation.

5 10 4

In the compound to be grafted, the substitution at position 9 is represented by formula (Ia), the substitutions in position 1 and 2 by formula (Ib).

According to a particular embodiment of the invention, the index n is equal to 1. This embodiment is advantageous because it favors the best yields, presumably due to a less steric hindrance when n is equal to 1. In this respect, the compound of formula (Ma) is particularly suitable.

(My) The compound according to the invention of formula (Ia) or (Ib) may be used as a polymer modifying agent having at least one carbon-carbon double bond. The polymer to be modified is preferably a diene polymer, more preferably a diene elastomer.

The term "diene polymer" is intended to include a polymer comprising diene monomeric units, in particular 1,3-diene monomer units. By "diene" elastomer (or indistinctly rubber) is to be understood in known manner an elastomer consisting at least in part (ie, a homopolymer or a copolymer) of monomeric diene units (monomers carrying two carbon-carbon double bonds, conjugated or not). Preferably, the diene elastomer is an elastomer chosen from the group consisting of polybutadienes (BR), polyisoprenes, butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. The process for modifying the polymer with the compound according to the invention of formula (Ia) or (Ib) comprises a hydrosilylation reaction. The hydrosilylation reaction is conventionally conducted in solution in the presence of a catalyst. Typically, the polymer to be modified, the compound to be grafted and the catalyst are dissolved in a solvent, preferably apolar, with stirring.

As apolar solvent, any inert hydrocarbon solvent which may be for example an aliphatic or alicyclic hydrocarbon such as pentane, hexane, heptane, isooctane, cyclohexane, methylcyclohexane or an aromatic hydrocarbon may be used. such as benzene, toluene, xylene and their mixtures. As a preference, methylcyclohexane or toluene is used.

As a catalyst, any catalyst known to catalyze the generally group VIII transition metal hydrosilylation reaction such as platinum, palladium, rhodium, ruthenium, iron, etc. can be used. Of these various catalysts used for the hydrosilylation reaction, platinum catalysts such as hexachloroplatinic acid hexahydrate (Speier catalyst) and platinum-1,1,3,3-tetramethyl-1 catalyst are preferably selected. 3-divinylsiloxane (Karstedt catalyst) and more preferably the Karstedt catalyst. The catalyst may be added to the reaction mixture in any customary form, however, preferably in the form of a solution in a solvent.

Preferably, the amount of total solvent, or solvent of the reaction medium, is such that the mass concentration of polymer is between 1 and 40% by weight, preferably between 2 and 20% and even more preferably between 2 and 10%. in said solvent. The term "total solvent" or solvent of the reaction medium is understood to mean all solvents used to solubilize the polymer to be modified, the compound to be grafted and the hydrosilylation catalyst.

The hydrosilylation reaction temperature is at least 20 ° C. and at most 120 ° C., preferably at least 50 ° C., or even at least 60 ° C. and at most 100 ° C., or even at most 90 ° C. vs.

The degree of grafting can be adjusted in a manner known to those skilled in the art, by varying different operating conditions, such as in particular the amount of compound to be grafted, the amount of polymer to be modified, the temperature or the time of reaction. The grafting yields are good, in particular of the order of 80%.

Thus, a wide range of grafting rates can be achieved without a secondary reaction being observed. Indeed, the compound to be grafted selectively reacts with the double bond or bonds of the polymer to be modified by hydrosilylation reaction, since the conjugated double bonds of the anthracene unit present in the compound to be grafted do not react in the hydrosilylation reaction. Thus, the grafting of the compound of formula (Ia) or (Ib) defined according to any one of the embodiments of the invention gives access to the synthesis of polymer bearing pendant conjugated carbon-carbon double bonds.

The compound to be grafted can be prepared from a halosilane compound. The halosilane compound has the formula (Nia) or (IIIb). It differs from the compound of formula (Ia) or (Ib) respectively by replacing the SiH function with a SiX function, X being a halogen atom. Preferably X represents a chlorine atom.

(Nia) (lllb)

The process for preparing the compound to be grafted comprises a halosilane reduction reaction. The reduction of a halosilane to a hydrogenosilane is a reaction well known to those skilled in the art, for example described by Lehman et al., Angewandte Chemie, International Edition, 48 (40), 7444-7447. The reduction reaction takes place in solution in a conventional manner by bringing together the halosilane and a reducing agent. Such halosilanes can be prepared by hydrosilylation of a precursor containing an anthracenyl group substituted with an unsaturated hydrocarbon group. As precursors may be mentioned 1-vinylanthracene, 1-allylanthracene, 2-vinylanthracene, 2-allylanthracene, 9-vinylanthracene, 9-allylanthracene. The hydrosilylation reaction conditions mentioned for polymer modification can be applied to the synthesis of the halosilane.

As a halosilane according to the invention, the compound of formula (IVa) may be mentioned in particular.

The aforementioned features of the present invention, as well as others, will be better understood on reading the following description of several embodiments of the invention, given by way of illustration and not limitation.

II. EXAMPLES OF CARRYING OUT THE INVENTION

I I. 1 Synthesis of the compound to be grafted:

The structural analysis as well as the determination of the molar purities of the synthesis molecules are carried out by a RM N analysis. The spectra are acquired on a BRUKER Avance 3 400 M Hz spectrometer equipped with a BBFO-zgrad "wide band" probe. 5 mm. The quantitative RM N ¹ H experiment uses a 30 ° single pulse sequence and a 3 second repetition time between each of the 64 acquisitions. The samples are solubilized in deuterated chloroform unless otherwise indicated. This solvent is also used for the lock signal unless otherwise indicated.

The RM N spectrum

allow the structural determination of molecules (see tables of attributions). The molar quantifications are made from the quantitative RM N 1D ¹ H spectrum. The compound intended to be grafted, the hydrogenosilane, is synthesized according to Scheme 3.

Step 1: Synthesis of 9-allylanthracene, CAS [23707-65-5], described by Karama, Usama et al, Journal of Chemical Research, 34 (5), 241-242; 2010; Mosnaim, D. et al., Tetrahedron, 1969, vol. 25, p. 3485 - 3492.

To a solution of allyl magnesium chloride (235 ml, 0.467 mol, 2.0 M in THF, Aldrich) is added, under argon, dropwise, a solution of anthrone (30.25 g, 0.155 mol) in anhydrous THF (300 ml). The reaction medium is refluxed for 2 hours. After cooling to 0 ° C, a solution ^of HCl (100 ml, 37% solution) in water (170 ml) was added dropwise. The reaction medium is stirred vigorously for 1 hour. After returning to ambient temperature, the organic phase is extracted with tert-butyl methyl ether (t-BuOMe, 3 times 100 mL), washed with a solution of K ₂ C0 _3, washed with ^water and dried by Na ₂ S0 ₄ . The combined organic phases are concentrated under reduced pressure to provide an orange oil. After purification on a chromatographic column (Al ₂ O ₃ / petroleum ether) an oil is obtained. The product crystallizes at + 4 ° C.

A green solid (30.45 g, 90% yield) with a melting point of 45 ° C. is obtained.

The molar purity is greater than 93% ( ¹ H NMR).

Step 2: Synthesis of (3- (anthracen-9-yl) propyl) chlorodimethylsilane CAS [150147-39-0]

To a solution of 9-allylanthracene (15.49 g, 0.071 mol) in anhydrous THF (100 ml) is added the Karstedt catalyst (50 mg, 2.4% Pt in xylene solution). A solution of dimethylchlorosilane (13.43 g, 0.142 mol, [1066-35-9], Aldrich) in anhydrous THF (30 ml) is then added dropwise. The reaction medium is stirred for 15 min and then heated at 60-65 ° C for 5-6 hours. The mixture is then cooled to 20 ° C and concentrated under reduced pressure to yield an oil.

After crystallization from pentane (300 ml), a yellow solid (17.85 g, 80% yield) with a melting point of 81 ° C. is obtained.

The molar purity is greater than 97% ( ¹ H NMR - ²⁹ Si).

NMR characterization

Step 3: Synthesis of (3- (anthracen-9-yl) propyl) dimethyl

To a suspension of LiAlH ₄ (1.20 g, 0.032 mol) in anhydrous THF (50 ml) is added a solution of (3- (anthracen-9-yl) propyl) chlorodimethylsilane (13.97 g, 0.045 mol). ) in anhydrous THF (100 ml) under argon, dropwise, keeping the temperature of the medium at 0 ° C. The reaction medium is stirred for 15 hours at room temperature. Then water (10 ml) is added dropwise. The mixture is stirred for 15-20 min. the organic phase is extracted with tert-butyl methyl ether (t-BuOMe, 100 ml). The organic phase is washed with water (3 x 50 ml) and dried over Na ₂ SO ₄ and concentrated under reduced pressure to give an oil. The ^oil obtained is diluted with cyclohexane (50 ml) and filtered through silica gel. Cyclohexane is concentrated under reduced pressure to yield an oil. The residue crystallizes at + 4 ° C.

A solid (10.13 g, 81% yield) with a melting point of 22-23 ° C is obtained. NMR characterization

II. 2 Polymer modification:

The polymer to be modified is an elastomer, copolymer of 1,3-butadiene and styrene (SBR). The compound to be grafted is the hydrogenosilane prepared according to the procedure described in paragraph ll.l.

Determinations of the levels of anthracene units grafted onto the polymer chain are carried out by NMR analysis. The spectra are acquired on a BRUKER 500 MHz spectrometer equipped with a BBIz-grad 5 mm wideband probe. Experience quantitative NMR ¹ H, uses a simple pulse sequence 30 ° and a repeating time of 3 seconds between each acquisition. The samples are solubilized in deuterated chloroform. The ¹ H NMR spectrum makes it possible to quantify the level of anthracene units grafted onto the chain by integrating the characteristic signals of the following protons:

5H Styrene pattern: 7.41ppm to 6.0ppm

1H PB1-2 + 2H PB1-4: 5.67ppm to 4.5ppm The calculation of the level of grafted anthracene units was carried out on the ¹ H spectrum by integrating the massif at 7.99 ppm considering 2 protons of the carbons numbered 1 and 8 of the anthracenyl unit, the symbol * symbolizing the attachment to the rest of the graft.

2 g of SBR are dissolved in 100 ml of toluene in a 250 ml reactor equipped with mechanical stirring, the whole is placed under an inert atmosphere (nitrogen). 3 mmol (0.93 ml) of hydrogenosilane and 200 μl of platinum-1,1,3,3-tetramethyl-1,3-divinylsiloxane in solution in xylene (Karstedt catalyst) (CAS no: 68478-92 -2) are added to the elastomer solution and the reaction medium is heated to 60 ° C.

After 24 hours at 60 ° C with stirring, the reaction medium is allowed to return to ambient temperature. Once it has returned to ambient temperature, the reaction medium is then coagulated twice in 250 ml of methanol. The elastomer dissolved in solution then undergoes an antioxidant treatment of 0.4 parts per hundred parts of elastomer (phr) of 4,4'-methylene-bis-2,6-tert-butylphenol and 0.4 parts per cent of elastomer (phr) of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine. The grafting yield is 79%. The molecular distribution of the modified polymer is identical to that of the polymer before modification.

Claims

claims

Compound of formula (la) or (Ib)

(la) (Ib)

in which

the symbol Y represents a hydrocarbon chain,

n being an integer from 1 to 3.

A compound according to claim 1 wherein the R symbols are alkyl, preferably methyl or ethyl.

Compound according to any one of claims 1 to 2 wherein the symbols R are identical.

A compound according to any of claims 1 to 3 wherein the Y symbol is alkanediyl.

A compound according to any one of claims 1 to 4 wherein the Y symbol is ethane-1,2-diyl or propane-1,3-diyl.

A compound according to any one of claims 1 to 5 wherein n is 1.

A process for preparing the compound of formula (Ia) or (Ib) defined in any one of claims 1 to 6 which comprises a reduction reaction of a halosilane which is formula (Nia) or (IIIb) and which differs from the compound of formula (Ia) or (Ib) respectively by replacing the SiH function with a SiX function, X being a halogen atom.

(Nia) (lllb)

The process of claim 7 wherein X is a chlorine atom.

9. Compound of formula (Nia) or (IIIb) defined in claim 7 or 8.

10. Use of a compound of formula (Ia) or (Ib) defined in any one of claims 1 to 6 as a modifier of a polymer having at least one carbon-carbon double bond.

11. Use according to claim 10 wherein the polymer is a diene polymer, preferably a diene elastomer.