Sulfur-containing aromatic tetracarboxylic acids and derivatives

Details Sulfur-containing aromatic tetracarboxylic acids and derivatives Sulfur-containing aromatic tetracarboxylic acids and derivatives

1990-06-12

1992-06-30

Dees, Jose G.

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

528352, 549242, 560 13, 562427, 562430, 562840, C07D30777, C07C31504, C07C31732, C07C 5160

Patent

active

051264625

DESCRIPTION:

BRIEF SUMMARY
The invention describes novel sulfur-containing aromatic tetracarboxylic acids and derivatives thereof and processes for their preparation.
Tetracarboxylic acid dianhydrides, such as, for example, pyromellitic acid dianhydride or benzophenonetetracarboxylic acid dianhydride, are used in industry, for example, for the preparation of polymers which are particularly heat-stable, that is to say the polyimides. Aromatic polyimides can be prepared, for example, in 2 stages by polyaddition and polycondensation. In the first stage, an aromatic diamine is subjected to polyaddition with an aromatic tetracarboxylic acid dianhydride to give the polyamide acid. In this form, the polymers are still readily soluble and can be processed, for example, to films and fibers. In the second stage, intramolecular cyclization takes place by removal of water by means of heat or chemically to give the insoluble polyimide which has a high heat stability (Macromol.Revs., 11 (1976) 161-208). Since, to a small extent, the polyamide acid converts to insoluble polyimide even at noon temperature, and hence the content of soluble polyamide acid reduces as the time increases, the polyamide acid solutions have only a limited shelf life.
Although the polyimides consisting exclusively of aromatic units have a high heat stability, they are completely insoluble and non-fusible and can thus be processed only with difficulty (J.Polym.Sci., A3 (1965) 1373-1390). This difficult processability makes the polyimides quite considerably more expensive and therefore excludes them from a number of interesting uses.
Soluble and/or fusible polyimides which are therefore easier to process can be obtained by changes to the chemical structure of the aromatic basic units, for example by incorporation of flexible chain elements (--CH.sub.2 --, --O--, --S-- or --CO--) or sterically bulky groups, but these products generally have a lower heat stability (J.Appl.--Polym.Sci., 26 (1981) 3837-3843). The polyamidoimides, which are prepared, for example, from aromatic tricarboxylic acid monoanhydrides and aromatic diamines, are products with a comparable profile of properties (U.S. Pat. No. 3,895,064). They are also soluble in polar organic solvents and usually have thermoplastic properties, but likewise have a lower heat stability in comparison with the aromatic polyimides.
The object of the present invention was to develop tetracarboxylic acids or derivatives thereof from which, for example, polyimides or polyamidoimides can be prepared by polyaddition with suitable diamines and subsequent cyclization, these products have an extreme heat stability and being soluble and/or fusible in the cyclized form and thus easily processable by conventional methods.
It has now been found that this object can be achieved with the aid of tetracarboxylic acids or derivatives thereof having aromatic, flexible chain elements containing --S-- and --SO.sub.2 -- bridges.
The present invention accordingly relates to aromatic tetracarboxylic acids or derivatives thereof of ##STR3## in which R denotes a divalent radical of the formula II: ##STR4## Ar denotes tri- or tetravalent aromatic radicals which are optionally substituted by one or more halogen atoms or mixtures thereof, it additionally being possible for the trivalent aromatic radical optionally to contain a, carboxyl group as a substituent, X, if Ar is trivalent, denotes the radical --CO--NH--, and if Ar is tetravalent denotes the imide radical of the formula III: ##STR5## in which N is in each case bonded to R, an Y and Z either together denote the anhydride radical --CO--O--CO-- or by themselves and independently of one another denote the radicals --COOH, --COCl or --COOR.sub.1, in which R.sub.1 represents an alkyl radical having 1-20 C atoms or an aryl radical having 6 to 20 C atoms.
All the known tri- or tetravalent aromatic radicals Ar which are derived, in particular, from the corresponding tri- or tetracarboxylic acids or their derivatives, such as, for example, anhydrides, esters or acid chlorides, are possible according to the

REFERENCES:
patent: 3895064 (1975-07-01), Brode et al.
patent: 4255313 (1981-03-01), Antonoplos et al.
patent: 4621134 (1986-11-01), Aritomi et al.
patent: 4724257 (1988-02-01), Aritomi et al.
Skroog et al., "Macromol. Revs." 11 161-208 (1976).
Skroog et al., "J. Polym. Sci." 3A 1373-1390 (1965).
Sheffer, "J. Appl. Polym. Sci." 26 3837-3843 (1981).

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