Method of making multidimensional polyesters

Abstract

The yield of fully substituted, multidimensional aromatic hubs in the condensation of hydroxyl and acid halide functionalities is improved by adding a thallium catalyst, such as thallium ethoxide (T1-OC.sub.2 H.sub.5), in the solvent.

Description

TECHNICAL FIELD

The present invention relates to a method for making multidimensional polyesters using thallium ethoxide as a catalyst.

BACKGROUND OF THE INVENTION

In our earlier applications we proposed the condensation of hydroxyl (--OH) and carboxylic acid (--COOH) or carboxylic acid halides (--COX) on an aromatic hub having at least three such functionalities. The condensation occurred in a suitable solvent, such as DMAC, under an inert atmosphere in the presence of triethylamine (TEA). We have found that, when reacting, for example, phloroglucinol with an acid chloride end cap of the formula: ##STR1## in DMAC and TEA that the resulting product is a mixture of ##STR2## The condensation is difficult to drive to completion (i.e., replacement of all the --OH groups) to yield the desired product (I). The yield of fully reacted multidimensional ester (I) can be improved, however, by replacing the TEA with thallium ethoxide (T1-OC.sub.2 H.sub.5).

The present invention is a method to improve the yield of fully-substituted multidimensional polyesters, particularly polyester oligomers having a trisubstituted phenylene hub and crosslinking hydrocarbon unsaturation at the end of each arm linked to the hub. The method involves conducting the esterification reaction in the presence of a thallium catalyst, such as thallium ethoxide, in a suitable solvent under an inert atmosphere. Preferably, the solvent includes DMAC and TEA.

BEST MODE CONTEMPLATED FOR THE PRESENT INVENTION

The yield of multidimensional polyesters can be improved by replacing triethylamine (TEA) in the condensation solution with thallium ethoxide (T1-OC.sub.2 H.sub.5) as a catalyst. Since the polyester oligomers that are synthesized are often used without isolation of products, we believe that the new product, richer in product (I) [i.e. the truly multidimensional ester] will yield better composites than are achieved with the multidimensional (I) and linear (II) blend made using TEA as a catalyst.

The method of the present invention is equally applicable to use of an acid halide hub such as cyuranic acid chloride with a mono- or difunctional imidophenol end cap monomer. Chain-extension can be achieved, also, by including dialcohols, diacid halides, or both in the condensation mixture.

We believe that TI-OC.sub.2 H.sub.5 will produce a higher yield of the tri-substituted hub. If the hub has more than three reactive hydroxyl or acid halide functionalities, the thallium ethoxide catalyst will promote more complete reaction (or substitution) than TEA.

While thallium ethoxide is preferred, it is possible that any lower alkoxy substituent on the metal will be active as a catalyst. That is, methoxy, propoxy, isopropoxy, n-butoxy, phenoxy, or the like may also display catalytic activity.

Accordingly, the present invention relates to the catalysis of the --OH/--COX or --OH/--COOH condensation with a thallium catalyst, and, particularly, to the preparation of multidimensional polyesters by the condensation of Ar.paren open-st.Q).sub.w with a corresponding alcohol (--OH), acid (--COOH), or acid halide (--COX) in a suitable solvent under an inert atmosphere with or without heating in the presence of thallium ethoxide,

wherein Ar=an aromatic radical of valency w; w=an integer greater than or equal to 3; and Q=--OH, --COOH, or --COX.

The aromatic radical will generally be phenyl or azalinyl, being the residue, for example of phloroglucinol or cyanuric acid chloride. Those compounds described in U.S. Pat. Nos. 4,617,390 or 4,709,008 may also be used as hubs, and amine compounds can be reacted with an acid anhydride to form polycarboxylic acids that are suitable hubs. Triaminobenzene or the polyamines of U.S. Pat. No. 4,574,152 are suitable reactants (precursors) in this context.

The simplest oligomers can be prepared by condensing about 1 mole of the hub with a crosslinking end cap monomer of the formula:

wherein .0.=phenyl; P=--COX, if the hub is a polyol, or --OH, if the hub is a polybasic acid; i=1 or 2; D=an unsaturated hydrocarbon radical that generally includes a segment selected from the group consisting of: ##STR3## R.sub.1 =lower alkyl, aryl, substituted alkyl, substituted aryl, lower alkoxy, aryloxy, halogen, or mixtures thereof; G=--O--, --S--, --SO.sub.2 --, --CH.sub.2, --CO--, --CHR--, --SO--, or --CR.sub.2 --; j=0, 1, or 2; T=allyl or methallyl; Me=methyl; and R=hydrogen, lower alkyl, or phenyl. These end cap monomers allow the multidimensional polyester oligomers to be cured into high performance, advanced composites that have use temperature that exceed (often substantially) their curing temperatures.

The arms of the multimdimensional oligomers can be extended if the reaction solution's components are adjusted. For example, the hub of the formula Ar.paren open-st.Q).sub.w can be simultaneously condensed with R.paren open-st.P).sub.2 wherein

Ar=an aromatic radical of valency w; w=a small integer greater than or equal to 3; Q=--COX, --OH, or --COOH; R=a divalent hydrocarbon radical, especially a phenoxyphenylsulfone; and P=--OH, if Q=--COX or --COOH, or --COX or --COOH, if Q=--OH with a crosslinking end cap manomer of the formula: Dd.sub.i --.0.--Q wherein D, i, .0., or Q are as previously defined.

The dialcohols or diacid halides include those compounds disclosed in U.S. Pat. No. 4,547,553 or in our copending applications.

The reaction solution may include four or more component mixtures but deleterious or interfering competitive reactions are likely to occur, dictating staged reaction rather than simultaneous condensation. For example, Ar.paren open-st.Q).sub.w can be condensed with R.paren open-st.P).sub.2 followed by addition of R.sub.1 .paren open-st.Q).sub.2 and D.sub.i --.0.--P to form a multidimensional polyester having extended arms (i.e., arms of relatively high average formula weight).

While preferred embodiments have been described, those skilled in the art will readily recognize alterations, variations, or modifications which might be made to the embodiments without departing from the inventive concept. Therefore, the claims should be interpreted liberally with the support of the full range of equivalents known to those of ordinary skill based upon this description. The claims should be limited only as is necessary in view of the pertinent prior art.

Claims

1. A method for making multidimensional polyesters comprising the step of reacting a compound of the formula: Ar.paren open-st.Q).sub.w wherein

Ar=a phenylene radical of valency w;

w=a small integer greater than or equal to 3;

Q=--OH or --COX; and

X=halogen

with substantially a stoichiometric amount of a compound of the formula: R-P wherein

R=a monovalent radical; and

P=--OH, if Q=--COX or --COX, if Q=--OH

in a solvent under an inert atmosphere in the presence of an effective amount of a thallium catalyst.

2. The method of claim 1 wherein the catalyst is thallium ethoxide.

3. The method of claim 2 wherein the solvent comprises dimethyl acetamide (DMAC).

4. The method of claim 2 wherein w=3 and the resulting product is substantially fully substituted phenylene.

5. The method of claim 2 wherein R, comprises hydrocarbon unsaturation.

6. The method of claim 4 wherein R comprises hydrocarbon unsaturation.

7. The method of claim 1 wherein Ar.paren open-st.Q).sub.w is phloroglucinol.

8. The method of claim 1 wherein Ar.paren open-st.Q).sub.w is cyuranic acid chloride.

9. The product of the process of claim 1.

10. The product of the process of claim 2.

11. A method for making multimdimensional polyester oligomers comprising the step of simultaneously condensing about 1 mole of a compound of the formula: Ar.paren open-st.Q).sub.w,

wherein

Ar=an aromatic radical of valency w;

w=a small integer greater than or equal to 3; and

Q=--OH or --COX wherein X=halogen

with about w moles of a compound of the formula: R.paren open-st.P).sub.2 and about w moles of a compound of the formula: R.sub.1 --Q,

wherein

R=a divalent hydrocarbon radical;

P=--OH, if Q=--COX, or --COX, if Q=--OH; and

R.sub.1 =a unsaturated hydrocarbon radical in a solvent under an inert atmosphere in the presence of an effective amount of a thallium catalyst.

12. The product of the process of claim 11.

13. The method of claim 1 wherein R is selected from the group consisting of:

D.sub.i --.0.--

wherein

.0.=phenylene;

i=1 or 2;

D= ##STR4## R.sub.1 =lower alkyl, aryl, substituted alkyl, substituted aryl, lower alkoxy, aryloxy, halogen, or mixtures thereof;

G=--O--, --S--, --SO.sub.2 --, --CH.sub.2 --, --CO--, --CHY--, --SO--, or --CY.sub.2 --;

j=0, 1, or 2;

T=allyl or methallyl;

Me=methyl; and

Y=any of hydrogen, lower alkyl, or phenyl.

14. The method of claim 13 wherein Ar.paren open-st.Q).sub.w is phloroglucinol.

15. The method of claim 13 wherein Ar.paren open-st.Q).sub.w is cyanuric acid chloride.

16. The method of claim 13 wherein the catalyst is thallium ethoxide.

17. The method of claim 16 wherein the solvent comprises DMAC (dimethyl acetamide).

18. The method of claim 11 wherein R.sub.1 is selected from the group consisting of:

D.sub.i --.0.--

wherein

.0.=phenyl;

i=1 or 2;

D=an unsaturated hydrocarbon radical that comprises a segment selected from the group consisting of: ##STR5## V=lower alkyl, aryl, substituted alkyl, substituted aryl, lower alkoxy, aryloxy, halogen, or mixtures thereof;

G=--O--, --S--, --SO.sub.2 --, --CH.sub.2 --, --CO--, --CHY--, --SO--, or --CY.sub.2 --;

j=0, 1, or 2;

T=allyl or methallyl;

Me=methyl; and

Y=any of hydrogen, lower alkyl, or phenyl.

19. The method of claim 18 wherein the catalyst is thallium ethoxide.

20. A method for making a multidimensional polyester comprising the step of reacting phloroglucinol with a compound of the formula:

R--COX

wherein

X=halogen;

R=D.sub.i --.0.--;

i=1 or 2;

.0.=phenylene;

D= ##STR6## R.sub.1 =lower alkyl, aryl, substituted alkyl, substituted aryl, lower alkoxy, aryloxy, halogen, or mixtures thereof;

G=--O--, --S--, --SO.sub.2 --, --CH.sub.2 --, --CO--, --CHY--, --SO--, or --C(Y).sub.2 --;

j=0, 1, or 2;

T=allyl or methallyl;

Me=methyl; and

Y=any of hydrogen, lower alkyl, or phenyl to form substantially completely substituted polyester oligomers of the formula:

.0..paren open-st.OOC--.0.--D.sub.i).sub.3

the reaction being catalyzed by thallium ethoxide in a solvent comprising dimethyl acetamide (DMAC), under an inert atmosphere in the presence of triethylamine.

21. A method for making a substantially fully-substituted multidimensional polyester at high yield, comprising the steps of:

reacting a compound of the formula: Ar.paren open-st.Q).sub.w

with substantially a stoichiometric amount of a second compound having a functionality reactive with Q to form an ester the reaction occurring in the presence of a catalytically effective amount of thallium ethoxide in a suitable solvent, including dimethyl acetamide, under an inert atmosphere in the presence of triethylamine, the reaction yielding essentially fully substituted Ar,

wherein

Ar=phenylene or a residue of cyanuric acid halide;

Q=--OH or --COX; and

X=halogen.