WO1997047661A1

WO1997047661A1 - Polymerisation catalyst and process

Info

Publication number: WO1997047661A1
Application number: PCT/GB1997/001589
Authority: WO
Inventors: David Mark Haddleton
Original assignee: University Of Warwick
Priority date: 1996-06-12
Filing date: 1997-06-12
Publication date: 1997-12-18
Also published as: US6310149B1; AU735085B2; DE69707452T3; AU3099297A; DE69707452D1; EP0906342A1; EP0906342B2; CA2258006C; ATE207082T1; EP0906342B1; CA2258006A1; DE69707452T2

Abstract

A first aspect of the invention provides a catalyst for addition polymerisation of olefinically unsaturated monomers comprising: a) a first compound MY where M is a transition metal in a low valency state or a transition metal in a low valency state co-ordinated to at least one co-ordinating non-charged ligand, Y is a monovalent, divalent or polyvalent counterion; b) an initiator compound comprising a homolytically breakable bond with a halogen atom; and c) an organodiimine, where at least one of the nitrogens of the diimine is not part of an aromatic ring; a second aspect of the invention provides a catalyst for addition polymerisation of olefinically unsaturated monomers comprising: d) a first component of the Formula [ML]n+ An- where M = a transition metal of low valency state, L = an organodiimine where at least one of the nitrogens of the diimine is not part of an aromatic ring, A = an anion, n = an integer of 1 to 3, m = an integer of 1 or 2; e) an initiator compound comprising a homolytically breakable bond with a halogen atom. Preferably, the organodiimine is a 1,4-diaza-1,3- butadiene, a pyridine carbaldelyde imine, an oxazolidone or a quinoline carbaldehyde. Processes for using the catalysts are also disclosed.

Description

POLYMERISATION CATALYST AND PROCESS

The present invention relates to a process for the atom transfer

polymerisation of olefinically unsaturated monomers in which molecular

weight control is achieved by the presence of certain transition metal,

especially copper, diimine complexes.

It is desirable to be able to produce high molecular weight polymers with

a low molecular weight distribution by catalysed addition polymerisation,

in particular of vinylic monomers. Hitherto this has been achieved by

polymerising via ionic processes typically in the presence of

organometallics such as alkyl lithium's which are sensitive as regards

reaction with water and other protic species. As such monomers

containing functional groups are not readily polymerised. The use of ionic

systems also precludes the use of solvents which contain protic groups

and/or impurities resulting in very stringent reaction conditions and

reagent purity being employed.

More recently radical polymerisation based on the combination of

a uransition metal halide and alkyl halide have been utilised. For example

Matyjasewski (Macromolecules (1995), vol 28. pages 7901-7910 and WO96/30421) has described the use of CuX (where X=C1, Br) in

con_junction with bipyπdine and an alkyl halide to give polymers of

narrow molecular weight distribution and controlled molecular weight.

This system suffers from the disadvantage that the copper catalyst is only

partially soluble in the system and thus a heterogeneous polymerisation

ensues. The level of catalyst which is active in solution is thus difficult to

determine. Percec (Macromolecules, (1995), vol. 28, page 1995) has

extended Matyjasewski^* s work by utilising arenesulphonyl chlorides to

replace alkyl chlorides, again this results in heterogeneous polymerisation.

Sawamoto (Macromolecules, (1995), vol. 28, page 1721 and

Macromolecules, (1997), vol. 30, page 2244) has also utilised a ruthenium

based system for similar polymerisation of methacrylates. This system

requires activation of monomer by aluminium alkyl, itself sensitive to

reaction with protic species which is an inherent disadvantage. These

systems have been described as proceeding via a free radical mechanism

which suffers from the problem that the rate of termination is > 0 due to

normal radical-radicai combination and disproportionation.

Surprisingly the inventors have found that the use of diimines such as 1,4-

diaza- 1 ,3 -butadienes and 2-pyridinecarbaldehyde imines may be used in

place of bipyridines. These ligands offer the advantage of homogeneous polymerisation and thus the level of active catalyst can be accurately

controlled This class of ligand also enables the control of the relative

stabili_ty of the transition metal valencies, for example. Cud) and Cu⁽II),

bv altcπns ancillary substituents and thus gives control over the nature of

the products through control over the appropnate chemical equilibrium.

Such a system is tolerant to trace impurities, trace levels of O_: and

func_tional monomers, and may even be conducted in aqueous media.

Λ tuπher advantage of the system of the invention is that the presence of

tree -radical inhibitors traditionally used to inhibit polymerisation of

commercial monomers in storage, such as 2. 6-dι-tert-butyl-4-

me_thv lphenol (topanol), increases the rate of reaction of the invention.

This means that lengthy purification of commercial monomers to remove

such radical inhibitors is not required. Furthermore, this indicates that the

system ot the invention is not a free-radical process. This is contrary to

the Mata_jaszewski and Sawamoto who show free-radical based systems.

Accordingly a first aspect of the invention provides a catalyst for addition

polymerisa_tion of olefinically unsaturated monomers, especially vinylic

monomers, composing: a₎ a first compound of formula 1

MY

where M is a transition metal in a low valency state or a transition

me_tal in a low valency state co-ordinated to at least one co-ordinating

» non-charsed ligand and Y is a monovalent or polyvalent counterion;

b₎ an initiator compound comprising a homolytically cleavable bond

with a halogen atom,^'

c ) an organodiimine. where one of the nitrogens of the diimine is not

part of an aromatic ring. Homoly_tically cleavable means a bond which breaks without

lin_tesral charge formation on eimer atom by homolytic fission.

Conven_tionally this produces a radical on the compound and a halogen

atom radical. For example:

Br

However, the increase in the rate of reaction observed by the

inventors wi_th free-radical inhibitors indicates mat true free-radicals do not

appear to be formed using the catalysts of the invention. It is believed that this occurs in a concerted fashion whereby the monomer is inserted

into the bond without formation of a discrete free radical species in the

system. That is duπng propagation this results in the formation at a new

carbon-carbon bond and a new carbon-halogen bond without free-radical

formation. The mechanism involves bndsins halosen atoms such as:

where:

ML is a transition metal-diimine complex as defined below.

A "free-radical" is defined as an atom or group of atoms having an

unuaired valence electron and which is a seϋarate entitv without

other interactions.

Transitional metals may have different valencies, for example Fe(II) and

FetHI), Cud) and Cu(II), a low valency state is the lower of the

commonly occurring valencies, i.e. Fe(II) or Cud"). Hence M in Formula I

is preferably Cud), Fe(II), Co(II), Ru(II) or Ni(II), most preferably Cu(I). Preferably the co-ordinating ligand is (CH₃CN)₄.Y may be chosen from Cl,

Br, F, I, NO₃, PF₆, BF₄, SO₄, CN, SPh, SCN, SePh or triflate (CF₃SO₃).

Copper (I) triflate may be, which may be in the form of a commercially

available benzene complex (CF₃SO₃Cu)₂ C₆H₆. The especially preferred

compound used is CuBr.

Preferably the second component (b) is selected from

RX

Formula 2

Formula 3 Formula 4 Formula 5

Formula 6 Formula 7 Formula 8

Form ula 9 Foπ nula 10 For mula 11

Formula 12

where R is independently selectable and is selected from straight, branched

or cyclic alkyl. hydrogen, substituted alkyl, hydroxyalkyl, carboxyalkvl or

substituted benzyl. Preferably the or each alkyl, hydroxyalkyl or

carboxyalkvl contains 1 to 20, especially 1 to 5 carbon atoms.

X is a halide. especially I, Br, F or Cl.

The second component (b) may especially be selected from Formulae 13

Formula 13

where:

X = Br, I or Cl, preferably Br

R^' = -H, -(CH₂)_pR" (where m is a whole number, preferably p = 1 to 20,

more preferably 1 to 10, most preferably 1 to 5, R" = H, oH, CooH,

halide. NH₂, S0₃, CoX - where x is Br. I or C) or:

Formula 14

R^m = -COOH, -COX (where X is Br, I, F or Cl), -OH, -NH, or -SO₃H,

especially 2-hydroxyethyl-2'-methyl-2^* bromopropionate.

Formula 15

Me. MeO. halogen.

Formula 16 Especially preferred examples of Formula 16 are:

Formula 16A Formula 16B

Formula 17 Formula 18 Formula 19 Formula 20

Formula 21 Formula 22 and

The careful selection of functional alkyl halides allows the production of

terminally functionalised polymers. For example, the selection of a

hydroxy containing alkyl bromide allows the production of α-hydroxy

terminal polymers. This can be achieved without the need of protecting

group chemistry. Component (c) may be a l,4-diaza-l,3-butadiene

R4

Formula 24

a 2-pyridinecarbaldehyde imine

Formula 25

An Oxazolidone

Rll R12

Formula 26 or a Quinoline Carbaldehyde

Formula 27

where R,, R₂ R₁₀, R_u, R₁₂ and R₁₃ may be varied independently and R,,

R₂, R₁₀ R_M, R₁₂ and R₁₃ may be H, straight chain, branched chain or cyclic

saturated alkyl, hydroxyalkyl, carboxyalkyl, aryl (such as phenyl or phenyl

substituted where substitution is as described for R₄ to R₉), CH₂Ar (where

Ar = aryl or substituted aryl) or a halogen. Preferably R,, R₂ R₁₀, R_n, R,₂

and R₁₃ may be a C, to C₂₀ alkyl, hydroxyalkyl or carboxyalkyl, in

particular C, to C₄ alkyl, especially methyl or ethyl, n-propylisopropyl, n-

butyl, sec-butyl, tert butyl, cyclohexyl, 2-ethylhexyl, octyl decyl or lauryl. R„ R₂, R₁₀, R„, R,₂ and R₁₃ may especially be methyl.

R₃ to R, may independently be selected from the group described for R,,

R₂, R₁₀, R_π, R₁₂ and R,₃ or additionally OCH_{2n +} , (where n is an integer

from 1 to 20), NO,, CN or 0=CR (where R = alkyl, benzyl PhCH₂ or a

substituted benzyl, preferably a C, to C₂₀ alkyl, especially a C, to C₄

alkyl).

Furthermore, the compounds may exhibit a chiral centre α to one of the

nitrogen groups. This allows the possibility for polymers having different

stereochemistry structures to be produced.

Compounds of general Formula 25 may comprise one or more fused rings

on the pyridine group.

One or more adjacent R, and R₃, R, and R₄, R₄ and R₂, R₁₀ and R,, R_g and

R,, R₈ and R₇, R₇ and R₆, R₆ and R₅ groups may be C₃ to C_g cycloalkyl,

cycloalkenyl, polycycloalkyl, polycycloalkenyl or cyclicaryi, such as

cyclohexyl, cyclohexenyl or norborneyl.

Preferred ligands include: Preferred ligands include:

Formula 28 Formula 29 Formula 30

Formula 32 Formula 33

Formula 34 Formula 35 Formula 36

Formula 37 Formula 38 Formula 39

Formula 45

Formula 46 Formula 47

Formula

Formula 50

Formula 51

where: * indicates a chiral centre :COH

R14 = Hydrogen. C, to C₁₀ branched chain alkyl, carboxy- or

hydroxy- C_t to C₁₀ alkyl.

A second aspect of the invention provides a catalyst for addition polymerisation of olefinicaily unsaturated monomers, especially vinylic

monomers, comprising:

a first component of Formula 51

wherein M = a transitional metal in a low valency state;

L = an organodiimine. where at least one of the nitrogens of the

diimine is not pan of an aromatic ring,

A = an anion

n = a whole integer of 1 to 3

m = an integer of 1 to 2.

(e) An initiator comprising a homolytically cleavable bond with a

halogen atom, as previously defined.

Preferably M is as previously defined for component (a). L may be a

compound according to Formula 24, 25, 26 or 27, as previously defined.

A may be F, Cl, Br, I, NO₃, SO₄ or CuX₂ (where X is a halogen).

The preferred initiators (e) are as defined for the fust aspect of the

invention. The invention also provides the use of the catalyst according to the fust or

second aspect of the invention in the addition polymerisation of one or

more olefinically unsaturated monomers and the polymerised products of

such processes.

The components (a), (b) and (c), or (d) and (e) may be used togemer in

any order.

The inventors have unexpectedly found that the catalyst will work at a

wide variety of temperatures, including room temperature and as low as -

15°C. Accordingly, preferably the catalyst is used at a temperature of

-20°C to 200°C, especially -20°C to 150°C, 20°C to 13oC, more preferably

90°C.

The olefinically unsaturated monomer may be a methacrylic, an acrylate, a

styrene. methacrylonitrile or a diene such as butadiene.

Examples of olefinically unsaturated monomers that may be polymerised

include memyl methacrylate, ethyl methacrylate, propyl methacrylate (all

isomers), butyl methacrylate (all isomers), and other alkyl methacrylates;

corresponding acrylates; also functionalised methacrylates and acrylates including glycidyl methacrylate, trimethoxysilyl propyl methacrylate, allyl

methacrylate. hydroxyethyl methacrylate, hydroxypropyl methacrylate,

dialkylaminoalkyl methacrylates; fluoroalkyl (meth)acrylates: methacrylic

acid, acrylic acid: fumaric acid (and esters), itaconic acid (and esters),

maleic anhydride: styrene. α-methyl styrene; vinyl halides such as vinyl

chloride and vinyl fluoride; acrylonitrile, methacrylonitrile; vinylidene

halides of formula CH, = C(Hal)₂ where each halogen is independently Cl

or F; optionally substituted butadienes of the formula CH, = C(R¹⁵)

C(R¹⁵) = CH, where R'⁵ is independently H, Cl to CIO alkyl, Cl, or F;

sulphonic acids or derivatives thereof of formula CH₂ = CHSO,OM

wherein M is Na. K, Li. N(R^I6)₄ where each R¹⁶ is independently H or Cl

ot V10 alkyl, D is COZ, ON. N(R'⁶)₂ or SO₂OZ and Z is H, Li, Na, K or

N(R^I6)₄; acrylamide or derivatives thereof of formula CH, =

CHCON(R^l6)₂ and methacrylamide or derivative thereof of formula CH, =

C(CH₃)CON(R^l6)₂. Mixtures of such monomers may be used.

Preferably, the monomers are commercially available and may comprise a

free-radial inhibitor such as 2. 6-di-tert-butyl-4-methylphenol or

methoxyplenol.

Preferably the co-catalysts are used in the ratios (c):(a) 0.01 to 1000, preferably 0.1 to 10, and (a):(b) 0.0001 to 1000, preferably 0.1 to 10,

where the degree of polymerisation is controlled by the ratio of monomer

to (b).

Preferably the components of the catalyst of the second aspect of the

invention are added at a ratio M:initiator of 3: 1 to 1: 100.

Preferably the amount of diimine : metal used in the systems is between

100: 1 and 1 : 1. preferably 5: 1 to 1: 1, more preferably 3: 1 tol d .

The reaction may take place with or without the presence of a solvent.

Suitable solvents in which the catalyst, monomer and polymer product are

sufficiently soluble for reactions to occur include water, protic and non-

protic solvents including propionitrile, hexane. heptane, dimethoxyethane,

diethoxyethane. tetrahydrofuran, ethylacetate, diethylether, N,N-

dimethylformamide, anisole, acetonitrile, diphenylether, methylisobutyrate,

butan-2-one, toluene and xylene. Especially preferred solvents are xylene

and toluene, preferably the solvents are used at at least 1% by weight,

more preferably at least 10% by weight.

Preferablv the concentration of monomer in the solvents is 100% to 1%, preferably 100% to 5%.

The reaction may be undertaken under an inert atmosphere such as

nitrogen or argon.

The reaction may be carried out in suspension, emulsion, mini-emulsion or

in a dispersion.

Statistical copolymers may be produced using the catalysts according to

the invention. Such copolymers may use 2 or more monomers in a range

of ca.0- 100% by weight of each of the monomers used.

Block copolymers may also be prepared by sequential addition of

monomers to the reaction catalyst.

Telechelic polymers, may be produced using calalysts of the invention.

For example, a functional initiator such as Formula 21 may be used with

transformation of the ωBr group to a functional group such as -OH or

-CO,H via use of a suitable reactant such as sodium azide.

Comb and graft copolymers may be produced using the calalysts of the invention to allow, for example, polymers having functional side chains to

be produced, by use of suitable reagents.

Embodiments of the invention will now be described by way of example

and with reference to the following figures:

Fig. 1 shows the structure of the ligand 2,6 dimemylamlineDAB;

Fig. 2 shows the crystal structure of the cation obtained by reacting

tBuDAB and CuBr together;

Figs. 3 and 4 show Mn dependence on conversion of different

monomer initiator ratios for styrene and methylmethacryiate respectively;

Fig. 5 shows Mw/Mn dependence on conversion for bulk

polymerisation of styrene at 80°C;

Fig. 6 shows kinetic plots for polymerisation of methylmethacryiate

at 90°C;

Fig. 7 shows the reaction scheme for the production of hydroxy

terminally functionalised PMMA. (i) Br,-P, (ii) Ethylene glycol, (iii)

CuBr/3/MMA, (iv) benzoyl chloride;

Fig. 8 shows a selected region from 'H NMR spectra of (a) 3, (b) 4

CH,-O-groups and -OCH₃ «= to Br and aromatic protons from

benzoyl group; Fig. 9 shows partial MALDI-TOF-MS of 3 between x = 8 and 11,

peaks conespond to lithium adducts of molecular ions with no observable

fragmentation;

Fig. 10 shows a plot showing how Mn from SEC increases with

conversion for experiments D-K.

Examples

Synthesis of Ligands

Diazabutadiene (DAB) Ligands

Glyoxal Aniline Dimethylaniline DAB

(phenylamine)

To a stirred solution of 40% aqueous glyoxal (0.25 mol) in a conical flask

was added the required amine dropwise (0.5 mol). After a period of time

a pale yellow solution formed which was taken up with water and filtered.

The resulting precipitate was dissolved in diethyl ether and poured over a

large excess of magnesium sulphate. The solution was left for twelve

hours to remove all the water and the solution was filtered. Ether was removed on a rotary evaporator then the product recrystallised from ether.

TenButyl DAB (tBu DAB) and isoPropyl DAB (iPr DAB) were similarly

manufactured using t-butylamine and isopropylamine respectively as die

starting amine. Such compounds are superior to 2,2-bipyridine in

accepting electron density

Pvridine Carbaldehvde Ligands

2-pyridinecarb- aniline aniline PCA

aldehyde

To a stined solution of pyridine carbaldehvde in ether was added an

equimolar quantity of amine. The solution was left for 3 hours then

poured over an excess of magnesium sulphate. The solution was filtered

and the ether removed on a rotary evaporator. Some ligands formed

yellow oils and were purified by distillation under reduced pressure.

Solids were purified by recrystallisation from ether.

tBu PCA, iPr PCA, nButyl PCA (nBu PCA), Dimethylaniline PCA, Diisopropylaniline PCA and methoxyaniline PCA were also made by

reacting 'BuNH,, 'PrNH,. ⁿBuNH₂, 2,6-dimethylaniline. 2.6-

diisoproxvlaniline and 4-methoxyaniline, respectively as the amine.

Characterisation of Ligands Lieands have been initially characterised by NMR and EI/CI mass spectrometry. Mass spec data is tabulated beiow

DIAZABUTΓENE CDAB) LIGANDS

PYRTDIJNE CARBALDEHYDE (PCA) LIGANDS

A crystal structure has been obtained of the ligand 2, 6 dimethyl aniline DAB (Fig. 15. This shows a E configuration of double bonds which must fold around the metal centre to form the catalyst. Synthesis of Catalysts

To a solution of ligand ( in acetone ) in a schienk was added copper bromide . chloride or Cu(CH,CN)BF₄ under nitrogen. The solution was filtered by cannuiar and piaced in a freezer. Solvent was removed by nitranon and the crystals examined by FAB mass spectrometry. Catalysts were synthesised with equimoiar quantities of ligand and anion or excess iieand (2:1). Both experiments resulted in the detection of a peak corresponding to CuL2 . L = l i gand.

Bipy (Bipyridyl ) i s included as a comparison.

A crystai structure has been obtained for the reaction of tBu DAB and CuBr indicating a tetrahedrai intermediate (Fig . 2 ) .

Polvmer Svnthesis

The catalysts were used to control the propagation of styrene and

methylmethacryiate.

All polymerisations were performed with excess ligand [L]:[Cu] 3:1 and

the catalyst is synthesised in situ.

General method for polymerisation of methylmethacryiate

To a Schienk to be purged with nitrogen was added 0.54mls etiiyl 2-

bromo-isobutyrate (0.00372 mols) in lOmls methylmethacryiate (0.0935

mols). The desired ligand was then added (0.01122 mols) and the entire

solution freeze pump thaw degassed. 0.536g copper bromide (0.00374

mols ) was then added whilst stirring. When the solution turned deep red

indicating formulation of the catalyst the schienk was immersed in an oil

bath at 90°C.

SUBSTITUTE SHEET (RULE 2B) Polymerisation results

All polymerisations are based on the following mole ratios.

Monomer : Initiator : Copper X . Ligand 100 1 1 3

Copper X = catalyst based on copper.

Styrene ( Sty) was i nitiated with 1 -phenylethyl bromide or chlorine.

Methylmethacryi ate (MMA) was initi ated with ethyl -2-bromo isobutyrate.

Iieand Imon. IX It/hrs I TΛC 1 Mn iMw I PDi I Conv% j

IBuDAB . |STY IBr 124 110 2.173 |4.438 12 I n 1 iPrDAB |STY IBr 124 110 1,975 172.587 138 15 dimeihyianiiineDAB ISTY IBr 124 no 467 |4.156 |9 180 | tBuPCA STY Br 124 110 338 11.110 |3.2 l i 1 aniiinePCA STY IBr 124 110 6,458 122.376 13.5 !4l i dixπeuivlaniline ISTY IBr 124 110 3.017 9,167 3 168 tBuPCA |STY IC1 120 130 42J51 102.776 12.45 120 nBuPCA ISTY (Cl 13 130 6,951 22.571 | 3.25 |+o iPrPCA (STY lei 120 1130 15.607 (41,125 (2.64 ,33 aniiinePCA (STY IBr 120 110 6.458 22.376 μ l*ι dimcύivtaniiinePCA ISTY Br 120 i 110 13.017 19.167 13 168

t-BuDAB was also investigated in more detail using different ratios of

Ligand (L), Initiator (I) and catalyst (Cu).

Stvrene at 100°C

ki Cu:I Mn PDI %Conv.

3 1 2173 2.0 11

3 20 2603 4.0 7

3 100 2169 5.8 8

1 1 2400 3.6 9

1 100 8042 14 7

MMA (100°C)

3 1 2020 4.1 Low

This shows that PDI may be controlled by varying the ratio of L:I and/or

Cu:I. Polymerisations with nBuPCA

The most successful ligand was nBuPCA which will form the following

copper (I) structure:

This catalyst has been used to obtain kinetic data for the polymerisation of

both styrene and methylmethacryiate. Temperature control is important to

prevent termination leading to tailing of the resulting MW distribution. If

termination is prevented men polydispersity will decrease with time. Mn

conversion plots have been obtained at different monomer to initiator

ratios.

Figs. 3 and 4 show Mn dependence on conversion at different

monomeπinitiator for styrene and methylmethacryiate at 80°C. Fig. 5 shows Mw/Mn dependence on conversion for bulk polymerisation

of styrene at 80°C.

Fig. 6 shows kinetic plots for the polymerisation of methylmethacryiate at

90°C.

Synthesis of Block Co-πolvmers

This was investigated using methylmethacryiate, benzylmethacrylate

(BzMA) and 2 hydroxyethylmethacrylate (HEMA) the results of which are

shown in the table below:

TABLE B

Statistical Copolvmers

An example of a statistical copolymer was produced using a compound of

Formula 16B as initiator and a compound of Formula 45 as die ligand. lg of 2-hydroxyethyl methacrylate with 9.36g of MMA (I. e. 7.7. mole%)

was polymerised with the following results:

Further experimentation

Further experimentation was also carried out using ligands of Formula 33.

Formula 33

This was svnthesised as follows:

30mls of diethylether was placed in a conical flask. 1.78mls of 2-pyridine

carbaldehvde (2.00g, 1.867 x 10^"2 moles) were added prior to 1.54mls or propylamine (1.1 lg, 1.873 x IO^'2 moles). The reaction mixture

immediately turns yellow. The mixture was stored for 10 minutes at room

temperature prior to the addition of magnesium sulphate and stirring for a

further 30 minutes. The reaction mixture was filtered and the volatiles

removed under reduced pressure. The product is isolated as a yellow oil.

Polymerisation

0.688g of copper (I) bromide (98% Aldrich)(4.796 x 10^"4 moles) were

added to lOmls of methylmethacryiate purified by passage down a column

containing basic alumina and 3A sieves under nitrogen (9.349 x IO^"2

moles) in 20 mis of xylene (deoxygenated by 3 freeze-pump-thaw cycles

and dried over 3A sieves for 12 hours). 0.2136g of A (1.44 x 10^'3 moles)

were added over 2 minutes with stirring at room temperature to give a

homogenous deep red/brown solution. 0.07mls of ethyl 2-

bromo_isobutyrate (0.0924g, 4.73 x 10^"4 moles) were added and the reaction

mixture heated to 90°C for 485 minutes. Samples were taken at intervals

and analysed for Mn and conversion, see table. After 485 minutes

poly(methylmethacrylate) was isolated by precipitation into methanol in

78.6% yield with Mn = 7020 and PDI (Mw/Mn) = 1.27. TIME % CONVERSION Mn PDI

120 16.47 2376 1.28

240 52.69 5249 1.22

300 61.02 6232 1.18

360 67.56 6742 1.21

485 78.56 7020 1.27

The Production of α-hvdroxy terminally functionalised PMMA

The initiator, ethyl-2-bromoisobutyrate was replaced wiύh hydroxy

containing alkyl bromide so as to produce ∞ -hydroxy terminally

functionalised PMMA without the need to employ protecting group

chemistry.

Ligands of Formula 33 were used in the polymerisation process.

2-hydroxyethyl-2'-methyl-2'bromopropionate was prepared as shown in

Fig. 7.

The conditions used in steps (1) and (ii) was as follows:

0.25g of red phosphorous (8.06 x 10^'3 mol) were added to 35.4ml (0.338 mol) of isobutyryl chloride. The mixture was placed under gentle reflux

and 20ml of bromine (0.338 mol) were added slowly over 8 hours. The

mixture was refluxed for a further 4 hours and die crude reaction mixture

added slowly to 350ml of anhydrous ethylene glycol (6.27 mol). The

reaction mixture was refluxed for 4 hours, filtered into 500ml of distilled

water and the product extracted into chloroform. After washing with

water and sodium hydrogen carbonate and drying over magnesium

sulphate the product was isolated as a colourless liquid after me removal

of solvent and vacuum distillation at 64.5°C and 0.1 Torr. 'H NMR

(CDC1₃, 373 K, 250.13 MHz) δ = 4.30 (t, J 9.6 Hz, 2H), 3.85 (t, J 9.6 Hz,

2H) 1.94 s, 6H), _l3C (Ε) NMR (CDC1₃, 373 K, 100.6 mHz) δ = 171.83,

67.30, 60.70, 55.72, 30.59, IR (NaCl, film) 3436 (br), 2977, 1736 (s),

1464, 1391, 1372, 1278, 1168, 1112, 1080, 1023, 950, 644, El MS: 213,

211 (mass peaks), 169, 167, 151, 149, 123, 121. The typical

polymerisation procedure used (steps iii and iv) was as follows:

0.1376 of copper(l)bromide (98%, 9.6 xlO^"4 mol) were added to 40ml od

xylene and 20ml of methyl methaqcrylate (0.187 mol). 0.4272g of 2 (2.89

x 10^'3 mol) were added and the mixture deoxygenated by one freeze-

pump-thaw cycle prior to the addition of 0.2029g of 3 (9.61 x 10^"4) mol at

room temperature. The deep red solution was heated at 90° C for 70

minutes. The final product was isolated by precipitation into hexanes. Atom transfer radical polymerisation of MMA using 3 as initiator in

con_junction with 2 and CuBr was earned out at 90°C in xylene

[MMA]:[3] = 20: 1. [ligand]: [CuBr]: [3] = 3: 1: 1 to give PMMA of structure

4 Polymerisation was stopped at low conversion. 7.65%, after 70

minutes, so as to reduce the amount of termination by radical-radical

reactions, reaction A. 'H NMR data (Fig. 8), clearly shows the presence

ot the hydroxyethyl ester group, originating from 2 and the methoxy «= to

the bromo group at the propagating end at δ 4.28. 3.82 and 3.74

respectively. The number average molecular mass. Mn, can be calculated

directly from NMR which gives a value of 2430 which compares

excellently with that obtained from size exclusion chromatography against

PMMA standards of 2320, PDI = 1.12 (when precipitated into hexanes Mn

- 2960. PDI = 1.12). This excellent agreement indicates that the product

has structure 4. This is confirmed by matrix-assisted laser desorption-

lonisation time of flight mass spectrometry. Fig. 9. We see one series of

peaks in the MALDI-TOF-MS indicating only one predominant structure

i.e. 4. For example, the peaks at m/z 1319.0 and 1419.2 correspond to

lithium adducts of 4 where x = 10 and 11 respectively, calculated m/z

1318.3 and 1418.4. The narrow PDI of 4 is indicative of k(propagation) >

k( termination) i.e. pseudo living polymerisation. Control over Mn and

PDI is obviously not affected detrimentally by the presence of primary alcohol group present in the initiator, which might have been expected to

complicate the reaction by coordination to the copper catalyst. Indeed the

PDI is narrower and the rate of polymerisation faster with 3 man that

obtained using a non functional initiator. This is currently under

investigation. Thus, controlled polymerisation with the copper complex as

catalyst can be utilised to give PMMA or structure 4 as die only

detectable product under these conditions. The hydroxy group can be

further reacted with benzoyl chloride to give 5 quantitively.

The terminal benzoyl group of 5 is observed by 'H NMR, Fig. 8(c) and is

detected by SEC with UV detection at 200 nm, 4 shows no absorption at

this wavelength. MALDI TOF shows a new series of peaks corresponding

to 5 e.g. peaks are now observed at m/z 1423.0 and 1522.8 for x = 10 and

11 , calculated m/z 1422.3 and 1522.4; this reaction is quantitive and no

peaks from residual 4 are observed. When die reaction is carried out at a

higher [MMA]: [3] ratio for 120 minutes a higher molecular weight

polymer is produced, Mn = 4540, PDI = 1.22, as expected, reactions B

and C. Again analysis shows terminal hydroxy functionally.

Living or pseudo living polymerisations have a low rate of termination

relative to rate of propagation. This is demonstrated by following a reaction with time, reactions D-K; L is the final product from this

reaction. Fig. 10 shows that Mn increases linearly with conversion, up to

approx. 80%. whilst PDI remains narrow for reaction with [MMA]:[3 } -

200. In this case the expected Mn (theory) at 100% conversion = [100/1 x

100 14 (mass of MMA)] + 220 (mass of end groups) = 20248 The PDI

is broader than would be expected for a true living polymerisation with

last initiation (theoretically 1 + 1/DP). However, PDI does not increase

with increasing conversion as would be expected for a reaction with

significant termination and this is most probably due to slow initiation

relative to propagation. _I2

In summary atom transfer polymerisation with the copper complex as

catalyst and 3 as initiator leads to °c-hydroxy functional PMMA. The

presence of the hydroxy group dunng the polymerisation does not reduce

the control over the polymensation, and a narrow PDI polymer with

controlled Mn is obtained. The reaction shows all the charactenstics of a

livmg/pseudo living polymensauon. The structure of the product has been

confirmed by MALDI-TOF-MS and NMR spectrometry. Furthermore the

hydroxy functionality can be further functionalised by reaction with acid

chlorides in a quantitative reaction.

" All reactions carried out with [2]: [CuBr]: [3] = 3:1:1. ^b 20 ml MMA in

40 ml xylene, ^c 5 mis MMA in 6 ml xylene. ^J From gravimetry. ' After

precipitation, otherwise as taken from reaction flask. Further Examples of Initiators and Ligands

In order to demonstrate the effectiveness of the catalysts across the range

of compounds chained, further experimentation was carried out.

Tvπical Polymerisation procedure

Methyl methacrylate (Aldrich) and xylene (AR grade. Fischer Scientific)

were purged with nitrogen for 2 hours prior to use. The initiator, ethyl-2-

bromoisobutyrate (98% Aldrich), and CuBr (99.999%. Aldrich) were used

as obtained and 2-pyridinal ^n" alkylimines were prepared as above. A

typical reaction method follows. CuBr (0.134g, [Cu]:[Initiator]=l : l) was

placed in a pre-dried Schienk flask which was evacuated and men flushed

with nitrogen three times. Methyl methacrylate ( 10ml) followed by 2-

pyridinal " alkylimine ([ligand] :[Cu]=2: l) was added with stirring and,

within a few seconds, a deep, brown solution formed. Xylene (20ml) and,

if appropriate, inhibitor were then added and the flask heated in a

thermostat controlled oil bath to 90°C. When the solution had equilibrated

ethyl-2-bromoisobutyrate (0.14ml, [Monomer] :[Initiator]= 100: 1) was

added. Samples were taken by pipette at certain times or the reaction

followed by automated dilatometry. This apparatus consists of a glass

capillary mbe that is set on top of a reaction vessel. The vessel is charged

with a complete reaction mixture that has been freeze-pump-tiiaw degassed to ensure no dissolved gases are released into the capillary. After the

vessei is fitted, the capillary is filled with degassed solvent and die

reaction mixture heated to the required temperamre. During

polymerisation monomer is converted to polymer with a decrease in the

volume of the mixture. This decrease in volume can be followed by

watching the meniscus fall in the capillary, a process done in tiiis case by

an electronic eye controlled by a computer program.

Characterisation of Polymers

Monomer conversion was calculated by gravimetry and/or ^lH NMR and

the molecular weights and molecular weight distributions (polydispersities)

found by get permeation chromatography using tetrahydrofuran as eluent

and me following columns (Polymer Laboratories): 5μm guard and mixed-

E (3000x7.5mm), calibrated with PL narrow molecular weight poly(methyl

methacrylate) standards with differential refractive index detection and/or

UV.

Claims

1. A catalyst for addition polymerisation of olefinically unsaturated

monomers composing:

a) A first compound

MY

where: M is a transition metal in a low valency state or a transition

metal in a low valency state co-ordinated to at least one co¬

ordinating non-charged ligand.

Y is a monovalent divalent or polyvalent countenon:

b) An initiator compound composing a homolytically cleavable bond

with a halogen atom: and

c) An organodiimine. where at least one of the nitrogens of the

diimine is not part of an aromatic ring.

2. A catalyst for addition polymerisation of olefinically unsaturated monomers comprising:

d) A first component of Formula

where: M = a transition metal of low valency state

L = an organodiimine where at least one of me

nitrogens of the diimine is not a part of an aromatic

ring.

A = an anion

n = an integer of 1 to 3

m = an integer of 1 to 2, and

e) An initiator compound comprising a homolytically cleavable bond

with a halogen atom.

3. A catalyst according to any previous claim wherein the

organodiimine is selected from:

a l,4-diaza-l,3-butadiene

R4

Formula 24 a 2-pyridine carbaldehvde imine

Formula 25

an oxazolidone R10

Formula 26

or a quinoline carbaldehvde

Formula 27

where:

R,, R,, R₁₀, R, ,, R₁₂ and R_l3 are independently selectable and may

be selected from H, straight chain, branched chain or cyclic stamrated

alkyl, hydroxyalkyl, carboxyalkyl, aryl, CH₂ Ar (where Ar is aryl or

substituted) or a halogen; R₃ to Rg are independently selectable and may be selected from H. straight

chain, branched chain or cyclic alkyl, hydroxyalkyl, carboxyalkyl, aryl,

CH_: Ar. a halogen. OCH_2n+1 (where n is an integer of 1 to 20), NO-,. CN,

O = CR (where R = alkyl, aryl, substituted aryl, benzyl PhCH_: or a

substituted benzyl).

4. A catalyst according to claim 3 wherein R, to R₁₃ are selected from

C, to C_:o alkyl. C, to C_:o hydroxyalkyl, C, to C₂₀ carboxyalkyl, n-

propylisopropyl, n-butyl, sec-butyl, tert-butyl, cyclohexyl, 2-ethylhexyl,

octyldecyl or lauryl.

5. A catalyst according to claim 3 or claim 4, wherein the

organodiimine comprises a chiral centre.

6. A catalyst according to claims 3 to 5 wherein one or more adjacent

R, and R₃, R₃ and R₄, R4 and R_;, R₁₀ and Rg, R₈ and Rg, R₈ and R₇, R₇

and R_f„ R₆ and R₅ groups are selected from alkyl, cycloalkenyl,

polycycloalkyl, polycycloalkenyl or cyclicaryl, containing 5 to 8 carbon

atoms. ₇. A catalys_t according to any previous claim whereⁱn M ⁱs selected

Cu(I)_, Fe(II), Co(II), Ru(II), NiOD Sm(II)^, Ag(D and Yb(II). from

8. A catalyst according to any of claims 1 and 3 to 7, wherein Y is

selected from Cl_, Br_, I, NO₃, PF₆, BF₄, SO, and CF₃ SO₃, CN^, SPh^, ScN

and SePh.

9. A catalys_t according to any of claims 2 to 7 wherein A is selected

from Cl_, Br_, F_, I_, N0₃, S0₄ and CuX₂ (where X is a halogen⁾.

10. A catalyst according to any previous claim^, wherein the initiator is

selected from:

RX Formula 2

Formula 3 Formula 4 Formula 5

Formula 6 Formula 7 Formula 8

R

Formula 9 Formula 10 Formula 11

x

Formula 12 where R is independently selectable and is selected from straight chain

alkyl, branched chain alkyl, cyclic alkyl, hydrogen, substimted alkyl,

hydroxyalkyl, carboxyalkyl, aryl and substimted aryl and substimted

benzyl.

X = a halide 11. A catalyst according to claim 10, wherein the initiator is

where:

X = Br, I or Cl, preferably Br

R' = -H,

-(CH₂)_pR" (where p is a whole number and R" = H, OH,

NH₂, SO₃H, COOH, halide, COX, where X is Br, I or Cl),

or

R^m = -COOH, -COX (where X is Br, I or Cl), -OH, -NH₂ or -S0₃H

12. A catalyst according to claim 11 wherein b is 2-hydroxyethyl-2'

bromopropionate.

13. The use of a catalyst according to any previous claim in the addition polymerisation of one or more olefinically saturated monomers.

14. The use of a catalyst according to claim 13 at a temperature

between -20°C to 200°C.

15. The use of a calalyst according to claim 14 between 20°C and

130₀C.

16. The use of a catalyst according claims 13 to 15, wherein the

olefinically saturated monomer is selected from methyl methacrylate, ethyl

methacrylate, propyl methacrylate (all isomers), butyl methacrylate (all

isomers), and other alkyl methacrylates; corresponding acrylates; also

functionalised methacrylates and acrylates including glycidyl methacrylate,

trimethoxysilyl proply methacrylate, allyl methacrylate, hydroxyethyl

methacrylate. hydroxypropyl methacrylate, dialkylaminoalkyl

methacrylates; fluoroalkyl (meth)acrylates; methacryhc acid, acrylic acid;

fumaric acid (and esters), itaconic acid (and esters), maleic anhydride;

styrene, α-methyl styrene; vinyl halides such as vinyl chloride and vinyl

fluoride; acrylonitrile, methacrylonitrile; vinylidene halides of formula

CH₂ = C(Hal)₂ where each halogen is independently Cl or F; optionally

substimted butadienes of the formula CH₂ = C(R¹⁵) C(R¹⁵) = CH₂ where Rⁱ⁵ is independently H, Cl to CIO alkyl, Cl, or F; sulphonic acids or

derivatives thereof of formula CH₂ = CHSO₂OM wherein M is Nas. K, Li,

N(R'⁶)₄, R¹⁶, or -(CH₂)₂-D where each R¹⁶ is independently H or Cl or

CIO alkyl, D is CO,Z, OH, N(R¹⁶)₂ or SO₂OZ and Z is H, Li, Na, K or

N(R^I6)₄; acrylamide or derivatives thereof of formula CH₂ =

CHCON(R^l6)₂, and methacryiamide or derivatives thereof of formula

CH₂=C(CH₃)CON(R¹⁶)₂. Mixtures of such monomers may be used.

17. The use of a catalyst, as defined in claims 1 and 3 to 12, according

to claims 13 to 16, wherein the ratio (c):(a) is 0.01 to 1000 and the ratio

of (a):(b) is 0.0001 to 1000.

18. The use of a calalyst as defined in claims 2 to 12 according to

claims 13 to 16 wherein the ratio of M:initiator is between 3: 1 and 1 : 100.

19. The use of catalyst according to claims 13 to 16, where the

polymerisation is undertaken in water, a protic or non-protic solvent.

20. The use of a catalyst according to claims 1 to 12 to produce a

statistical copolymer, a block copolymer, a telechelic polymer or a comb

and graft copolymer of monomers according to previous claim.