DE3700195A1 - Polymerisation of acrylic derivatives - Google Patents

Abstract

Acrylic derivatives are polymerised thermally in the presence of compounds which have or contain the following structure <IMAGE>

Description

The invention relates to a method for polymerization of acrylic derivatives in the presence of certain phosphorus compounds as polymerization catalysts.

It is known from "Makromolekulare Chemie", 153 (1972), 289 to 306 that phosphorylides can start the anionic polymerization of vinyl monomers, salt-free ylides of the formula R₃P = CH-X and salt-containing ylides of the formula R₃P = CH₂ · LiBr in question come. At -60 ° C, the starting effectiveness of the salt-free ylides can only be determined with acrylonitrile and methacrylonitrile. From Journal of Polymer Science, "Polymer Letters Edition", 21 (1983), pages 217-222, it is known to use a special triphenylphosphonium ylide for the photopolymerization of methyl methacrylate (MMA). According to this, the triphenylphosphonium ethoxycarbonyl methylide used should not initiate the polymerization of methyl methacrylate under thermal conditions (60 ° C.). Further polymerization processes for acrylic derivatives are known from EP-A-1 45 263 and EP-A-1 21 439. An overview of the stereospecific polymerization of α- substituted acrylic acid esters can be found in "Advances in Polymer Science", 31 (1979).

The use of ylides in the nickel-catalyzed polymerization of ethene and acetylene is already known, for example, from DE-A-33 36 500 and 34 03 493. From Polymer Preprints, ACS Div. Polym. Chem. (1986), 27, 165-166, polymerization-active ketene silyl acetals are already known as reaction products of phosphites with α, β- unsaturated esters. However, only very special phosphonates are obtained here.

The invention relates to a method for thermal Polymerization of acrylic derivatives in the presence of a catalyst, characterized in that the Catalyst corresponds to the following structure or one contains such

in what mean
R¹, R² and R³ independently of one another are customary substituents for organophosphorus compounds, especially for P-ylides, in particular straight-chain or branched C₁-C₂₀-alkyl radicals, C₆-C₁₂-aryl radicals, C₂-C₃₀-alkenyl radicals, C₃-C₈-cycloalkyl radicals, C₆-C₁₂ -Aryl-C₁-C₂₀-alkyl radicals, C₁-C₂₀-alkyl-C₆-C₁₂- aryl radicals, halogen, hydroxy, C₁-C₂₀-alkoxy radicals, C₆-C₁₂-aryloxy radicals, C₁-C₂₀-alkylamino, C₆-C₁₂- arylamino, C₁ -C₂₀-alkylphosphino, C₆-C₁₂-arylphosphino and the above hydrocarbon radicals substituted in particular by cyano, sulfonate, silyl, stannyl, halogen, hydroxy, amino, C₁-C₂₀-alkylamino, C₆-C₁₂-arylamino, nitro, C₁-C₂₀-alkylphosphino, C₆-C₁₂-arylphosphino, C₁-C₂₀-alkoxy or C₆-C₁₂-aryloxy, alkali metal, in particular lithium or the radical -CO-R⁷, where R⁷ is hydrogen or has a meaning given under R¹ and where R² is the meaning

may have,

R⁴, R⁵ and R⁶ independently of one another hydrogen, a sulfonate radical, an alkali metal, in particular lithium, silyl, stannyl radicals, phosphino radicals and boranyl radicals, acyl, halogen, cyano, a radical -CO-R⁷ or one specified under R¹ Rest,
and at least two of the radicals R¹ to R⁷ together can be part of an iso- or heterocyclic ring, in particular R⁵ and R⁶ together with the common carbon atom can form a saturated or unsaturated iso- or heterocyclic ring,
with the exception of those compounds of formula (I) which are ketene silyl acetals, obtained by adding silyl phosphites to α, β- unsaturated esters
and wherein the polymerization is carried out at temperatures above -20 ° C., in particular above 20 ° C., in particular between 40 to 120 ° C.

Preferably R¹, R² and R³ are independently for phenyl or C₁-C₆-alkyl, especially isopropyl, X for CHR⁵ and R⁵ for hydrogen or C₁-C₆ alkyl.

In a further preferred embodiment preferred acyl radicals R⁴ to R⁶ acetyl, formyl and Benzoyl, carbomethoxy, carboethoxy.

In a further preferred embodiment, X for CH₂, CH-phenyl, N-silyl and C (CN) ₂, CH-vinyl, CH- Propenyl and CH-styryl and for CH-acyl, especially CH- Formyl, CH-acetyl, CH-benzoyl, CH-carbomethoxy, and for C (acetyl) ₂ and C (benzoyl) ₂.

The catalyst to be used according to the invention can also be a single or multi-core main group complex, the a structure according to formula (I) given above contains. A preferred complex corresponds to the following Formula (II)  

wherein
R¹, R², R³ and X have the meaning given under formula (I) and mean in

n 1 to 4, my main group element of the 1st to 4th, in particular the 3rd and 4th group, linseed ligand, preferably hydrogen, halogen or an organic radical, in particular alkyl, aryl or aralkyl, where m <1 L 1 to m can take on meanings, m 1-3.

The catalysts to be used according to the invention can optionally be electrically charged, the charge compensation done by a counter ion.

M is in particular an element of the 3rd or 4th Main group, especially boron, aluminum, silicon or Tin. Preferred complexes of this type are

(Ph₃PCH₂ · AlEt₃),
(Ph₃PCH₂SiMe₃) ⁺Cl ^- ,
(Ph₃PCHCHO · SnMe₃) ⁺Cl ^- ,
(Ph₃PCHCMeO · SiMe₃) ⁺Cl ^- ,
(Ph₃PCHCPhO · BF₃).

In another preferred embodiment, as Catalyst the protonation product of the above Formula (I) used. Preferred protonation products are obtained by e.g. B. Implementation of a  Phosphine with an organyl halide or by reaction of an ylid with an acid, s. H. J. Bestmann and R. Zimmermann, progress d. chem. Forsch., 20 (1970).

Compounds of the formula (I) given above are known some major group complexes and the protonation products are also known or after customary methods can be produced (see e.g. H. Schmidbaur, Assounts of Chemical Research, 8, 62-70 (1975), and there literature cited). The complexes (II) are for example obtainable by reacting a Lewis acid with a compound of formula (I) above.

In a further preferred embodiment at least one of the substituents of formula (I) Siloxy substituted alkenyl.

In a further preferred embodiment, the Polymerization in the presence of a nucleophile, e.g. B. Fluoride, in particular a bifluoride, performed will.

Suitable acrylic derivatives are, for example, methyl methacrylate, Butyl methacrylate, sorbyl acrylate and methyl acrylate, Lauryl methacrylate, ethyl acrylate, butyl acrylate, Acrylonitrile, 2-ethylhexyl methacrylate, 2- (dimethyl amino) ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, 3,3-dimethoxypropyl acrylate, 3-methacrylic propyl acrylate, 2-acetoxyethyl methacrylate, p-tolyl methacrylate, 2,2,3,3, 4,4,4-heptafluorobutyl acrylate, ethyl 2-cyanoacrylate, 4- Fluorophenyl acrylate, 2-methacryloxyethyl acrylate and Ethyl 2-chloroacrylate, glycidyl methacrylate, 3-methoxy propyl methacrylate, phenyl acrylate, allyl acrylate and  Methacrylate, unsaturated esters of polyols e.g. B. Ethylene glycol diacrylate, diethylene glycol diacrylate, etc.

Particularly preferred acrylic derivatives are acrylic and meth acrylic acid esters of mono- or polyhydric alcohols, but preferably acrylic and methacrylic acid esters of monohydric, aliphatic alcohols with 1 to 12 Carbon atoms.

In a preferred embodiment, copolymers made with at least two different acrylic derivatives. Combinations are particularly preferred

Ethyl acrylate / butyl acrylate
Methyl methacrylate / butyl acrylate
Ethyl acrylate / butyl acrylate / glycidyl methacrylate

In a further preferred embodiment, the Method used in a manner known per se for To produce block copolymers.

The polymerization can be carried out in bulk or in a suitable Solvents are carried out. Suitable Above all, solvents are aprotic solvents such as benzene, toluene, xylene, ketones such as acetone, methyl ethyl ketone, Esters such as ethyl acetate, ethers such as Tetrahydrofuran, nitriles, e.g. B. acetonitrile. The catalyst concentration is preferably at least 0.01 mmol per 100 mol of monomer. The catalyst can be used as pure substance or as a solution or suspension, e.g. B. in THF, toluene or acetonitrile can be introduced.  

The polymerization can be both continuous and be carried out discontinuously.

For the polymerization z. B. The following procedures:

• a) Submission of the fixed, suspended or dissolved Catalyst (or its components), addition of the / of the monomers at the desired temperature simultaneously or successively,
• b) presentation of the monomer (s), injection of the catalyst sator solution or suspension (or its Components) at the desired temperature,
• c) continuous metering of the catalyst solution (or its components) and the monomer (s) predetermined desired polymerization conditions (Pressure, temperature).

The polymerization temperature is preferably +40 to + 120 ° C.

The polymers produced according to the invention preferably have a molecular weight Mn of <10 kg / mol.

The molecular weight distribution of the polymers can be varied within a wide range, for example it is possible to produce polymers with a polydispersity Mw / Mn between 1 and 2, where Mw and Mn are defined as follows:

Mw : weight average molecular weight Mn : number average

The method according to the invention also allows: Selection of suitable acrylic compounds, the physical Properties such as B. Glass transition temperature and hardness to influence in a wide range.

In the following examples, the following information is given for characterization: intrinsic viscosity, molecular weight and molecular weight distribution using gel permeation chromatography (GPC). The following abbreviations are used to label the substances:
Ph: phenyl, Pr ⁱ : iso-propyl, Me: methyl, PMMA: polymethyl methacrylate, MMA: methyl methacrylate, Et: ethyl.

Example 1

In a 2-liter three-necked flask, 1001 g (10 mol) of dry, freshly distilled methyl methacrylate (MMA) were heated to 60 ° with the exclusion of air and moisture. 250 mg (1 mmol) of triisopropylphosphine benzylidene (Pr₃ ⁱ PCHPh) in 10 ml of toluene were injected. The mixture was stirred at 60 ° C. for 1 hour and the polymerization was then stopped with methanol. After precipitation in methanol, washing and drying, 78 g of solid white polymethyl methacrylate (PMMA) were obtained.
Intrinsic viscosity in methylene chloride at 25 ° C 1.7 dl / g
GPC: Mn = 214 kg / mol, Mw / Mn = 4.7.

Example 2

According to example 1, but
Catalyst: 276 mg (1 mmol) of Ph₃PCH₂ in 20 ml of toluene
Polymerization temperature: 100 ° C
Polymerization time: 2 hours
Polymer yield: 85 g PMMA
Intrinsic viscosity in methylene chloride at 25 ° C = 6.1 dl / g
GPC: Mn = 1129 kg / mol, Mw / Mn = 2.5

Example 3

According to example 1, but
Catalyst: 349 mg (1 mmol) of Ph₃PNSiMe₃ in 20 ml of toluene
Polymerization temperature: 100 ° C
Polymerization time: 2 hours
Polymer yield: 66 g
Intrinsic viscosity in methylene chloride at 25 ° C = 6.0 dl / g
GPC: Mn = 1076 kg / mol, Mw / Mn = 2.7

Example 4

According to example 1, but
Catalyst: 326 mg (1 mmol) of Ph₃PC (CN) ₂ in 20 ml of toluene
Polymerization temperature: 100 ° C
Polymerization time: 2 hours
Polymer yield: 116 g
Intrinsic viscosity in methylene chloride at 25 ° C = 4.8 dl / g
GPC: Mn = 678 kg / mol, Mw / Mn = 3.3

Example 5

According to example 1, but
Catalyst in 20 ml of toluene
Polymerization temperature: 100 ° C
Polymerization time: 2 hours
Polymer yield: 267 g PMMA
Intrinsic viscosity in methylene chloride at 25 ° C = 3.8 dl / g
GPC: Mn = 271 kg / mol, Mw / Mn = 6.9

Example 6

To a solution of 3.80 g (10 mmol) of Ph₃PCHCPhO in 100 ml of toluene, 10 mmol of boron trifluoride etherate BF₃ · O (C₂H₅) ₂ were added. A precipitate formed immediately. After 10 minutes, it was decanted off, washed with ether and dried in vacuo. 522 mg of the white powder were used for the subsequent polymerization, the catalyst being stirred into 1001 g of boiling methyl methacrylate as a solid. After polymerization for one hour at 100 ° C., 10 ml of methanol were added to the now viscous flask contents and the PMMA formed was then precipitated in 3 l of methanol, washed and dried.
Polymer yield 65 g PMMA.

Example 7 (Production of the initiator Ph₃PCH₂ · Me₃SiCl)

Excluding air and moisture, 2.76 g (10 mmol) Ph₃PCH₂ and 1.08 g (10 mmol) Me₃SiCl in 200 ml Toluene reacted at 20 ° C. The silylation product of the ylid immediately precipitated white crystalline and after stirring for 10 minutes by Schlenk filtration isolated, washed and dried in a high vacuum.

Example 8

Excluding air and moisture, 276 mg (1 mmol) of Ph₃PCH₂ and 108 mg (1 mmol) of Me₃SiCl in 20 ml of dry, N₂-saturated toluene were reacted at 20 ° C for 10 minutes. The resulting suspension was injected into 1001 g (10 mol) of MMA, which had been heated to 100 ° C. After 2 hours the polymerization was stopped with methanol and precipitated in methanol. After washing with methanol and drying in vacuo, 63 g of solid PMMA were weighed out.
Intrinsic viscosity in methylene chloride at 25 ° C 3.4 dl / g
GPC: Mn = 641 kg / mol, Mw / Mn = 2.7

Example 9

10 g (32 mmol) of Ph₃PCHCHO were dissolved in 200 ml of chloroform and with an excess of trimethylchlorosilane added, heated to boiling and after 3 hours the Silyl complex Ph₃PCHCHO · Me₃SiCl precipitated with ether and washed and dried in vacuo.

Example 10

Under a protective gas, a suspension of 2.06 g (5 mmol) of Ph₃PCHCHO · Me₃SiCl (see Example 9) in 25 ml of acetonitrile and 25 pipetted ml THF. After heating to about 80 ° C., the reaction was allowed to take place for about 2 hours. The PMMA formed was precipitated in 1 liter of methanol, washed and dried in vacuo.
Polymer yield: 5.9 g
Intrinsic viscosity in methylene chloride at 25 ° C = 0.7 dl / g
GPC: main mass (approx. 90%) Mn = 140 kg / mol, Mw / Mn = 1.5

Example 11

Excluding air and moisture, 278 mg (1 mmol) of Ph₃PO were reacted with 199 mg (1 mmol) of Me₃SnCl in 20 ml of dry, N₂-saturated toluene with stirring for 10 minutes at 20 ° C and then in 1001 g of freshly distilled, dry methyl methacrylate , which had been heated to 100 ° C, injected. After 2 hours, the PMMA formed was worked up as described above.
Polymer yield: 207 g
Intrinsic viscosity in methylene chloride at 25 ° C = 5.8 dl / g
GPC: Mn = 929 kg / mol, Mw / Mn = 2.8

Example 12

To 16.7 g (50 mmol) of Ph₃PCHCOOMe in 100 ml of chloroform 10.95 g (55 mmol) of Me₃SnCl in 50 ml of chloroform added dropwise, 30 minutes at 20 ° C and 3 hours at 60 ° C touched. The mixture was then concentrated and ether was added and the product isolated by Schlenk filtration, washed and dried in vacuo.

Example 13

2.13 g (4 mmol) of Ph₃PCHCOOMe · Me₃SnCl were stirred with 0.78 g (0.8 mmol) of AgBF₄ in 20 ml of acetonitrile and 20 ml of THF at 20 ° C for 10 minutes. The mixture was then filtered through a reverse frit and the filtrate was injected into 40 g (0.4 mol) of 80 ° MMA. It was worked up after 2 hours.
Polymer yield: 18.7 g
Intrinsic viscosity in methylene chloride at 25 ° C 0.6 dl / g
GPC: Mn = 76 kg / mol, Mw / Mn = 1.7

Example 14

0.58 g (1 mmol)
Ph₃PCHCPhO · Me₃SnCl
with 0.015 g (0.2 mmol) of KHF₂ in a mixture of 5 ml of THF and 5 ml of acetonitrile at 25 ° C for 10 minutes. This preformed catalyst was injected into a 40 liter autoclave containing 9811 g (98 mol) of ethyl acrylate and 284 g (2 mol) of glycidyl methacrylate and 10 095 g of toluene. The mixture was heated to 100 ° with stirring. After 5 hours, the conversion was about 90%. The polymerization was stopped after 10 hours, and the product was precipitated with n-hexane and dried in vacuo.
Intrinsic viscosity in methylene chloride at 25 ° C = 0.9 dl / g
GPC: monomodal distribution Mn = 57 kg / mol, Mw / Mn = 3.2

The polymer contains 3.05% by weight glycidyl methacrylate.

Claims (12)

1. A process for the thermal polymerization of acrylic derivatives in the presence of a catalyst, characterized in that the catalyst corresponds to the following structure or contains one in what mean
R¹, R² and R³ independently of one another are usual substituents for organophosphorus compounds, where R² is the meaning may have, R⁴, R⁵ and R⁶ independently of one another are hydrogen, alkali metal, sulfonate, silyl, stannyl, phosphino or boranyl radicals, acyl, halogen, cyano, a radical -CO-R⁷ or a radical indicated under R¹,
R⁷ is hydrogen or a radical indicated under R¹,
wherein at least two of the radicals R¹ to R⁷ together can be part of a ring, the use of ketene silyl acetals, which are obtained by addition of silyl phosphites to α, β- unsaturated esters, is exempted and the process is further characterized in that the polymerization is carried out above -20 ° C. 2. The method according to claim 1, characterized in that mean
R¹ to R³ optionally substituted straight-chain or branched C₁-C₂₀-alkyl residues, C₆- C₁₂-aryl residues, C₂-C₃₀-alkenyl residues, C₃- C₈-cycloalkyl residues, C₆-C₁₂-aryl-C₁-C₂₀- alkyl residues, C₁-C₂₀-alkyl- C₆-C₁₂ aryl radicals, halogen, hydroxy, C₁-C₂₀ alkoxy radicals, C₆-C₁₂ aryloxy radicals, C₁-C₂₀- alkylamino, C₆-C₁₂-arylamino, C₁-C₂₀- alkylphosphino, C₆-C₁₂-arylphosphino radicals. 3. The method according to at least one of the preceding claims, characterized in that at least one of the residues
R¹ to R³ is substituted by cyano, sulfonate, silyl, stannyl, halogen, hydroxy, amino, C₁- C₂₀-alkylamino, C₆-C₁₂-arylamino, nitro, C₁- C₂₀-alkylphosphino, C₆-C₁₂-arylphosphino, C₁- C₂₀- Alkoxy, C₆-C₁₂ aryloxy, an alkali metal atom or a radical -CO-R⁷. 4. The method according to claim 1, characterized in that R¹ to R³ are phenyl or isopropyl. 5. The method according to claim 1, characterized in that X means: CH₂, CH-vinyl, CH-propenyl, CH- Styryl, CH-phenyl, CH-formyl, CH-acetyl, CH- Benzoyl, CH-carbomethoxy, C (acetyl) ₂, C (benzoyl) ₂, N-silyl or C (CN) ₂ means. 6. The method according to claim 1, characterized in that a complex of the following formula (II) is used as catalyst (R¹R²R³PX) _n ML _m (II) wherein
R¹, R², R³ and X have the meaning given in claim 1 and in which n is 1 to 4 My main group element of the 1st to 4th main group, LLigand, m 1-3. 7. The method according to claim 6, characterized in that that M represents an element of the 3rd or 4th main group. 8. The method according to claim 1, characterized in that at least one of the P substituents according to formula I is a siloxy-substituted alkenyl radical. 9. The method according to claim 1, characterized in that as a catalyst a protonation product Compound according to formula (I) is used. 10. The method according to claim 1, characterized in that an ester is used as the acrylic acid derivative becomes. 11. The method according to claim 1, characterized in that various acrylic derivatives are copolymerized. 12. The method according to at least one of the preceding Claims, characterized in that the polymerization performed in the presence of a nucleophile becomes.