| PATENT NUMBER | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT EXAMPLES |
EXAMPLE 4 Solution Polymerization of an Insoluble Polyanhydride with a soluble Acid Acceptor Insoluble polyanhydrides, poly(1,3-bis(p-carboxyphenoxy)propane) and poly(terephthalic anhydride), were polymerized as above but using only soluble amines such as TEA or pyridine as the acid acceptors. The polymers precipitated during the reaction and were isolated by filtration. The results are shown in Table IV. TABLE IV __________________________________________________________________________ Solution Polymenzation of Insoluble Polymers Using Phosgene and Diphosgene as Coupling Agents. Coupling Acid Molecular Weight IR MP Acid.sup.c Agent.sup.b Acceptor.sup.c Mw Mn (cm.sup.-1) (.degree.C.) __________________________________________________________________________ 1. Adipic acid P TEA 7600 3350 1820 1735 70-73 2. " P PVP 8300 3600 1810 1740 70-74 3. " D TEA 6900 3200 1820 1740 69-73 4. Dodecanoic P TEA 14100 6500 1810 1740 92-95 acid 5. Dodecanoic P PVP 12600 5900 1810 1740 90-95 acid 6. Dodecanoic D PVP 13750 4800 1805 1740 92-94 acid 7. Terephthalic P TEA -- -- 1780 1735 >300 acid.sup.a 8. Terephthalic P Pyridine -- -- 1780 1735 >300 acid.sup.a 9. Therphthalic D TEA -- -- 1780 1730 >300 acid.sup.a 10. PDP P TEA 8400 3650 1800 1735 98-101 11. " P PVP 7950 2100 1805 1740 100-102 12. " D TEA 9200 2350 1805 1735 98-102 13. CPP.sup.a P TEA -- -- 1780 1730 262-265 14. " P TEA -- -- 1780 1735 265-266 15. " D TEA -- -- 1780 1735 264-266 16. PHE--GLU D TEA 7500 2800 1800 1740 -- 17. " D PVP 4680 2400 1800 1740 -- __________________________________________________________________________ .sup.a P is phosgene solution, D is diphosgene, .sup.b Polymers are insoluble .sup.c PDP is phenylenedipropionic acid, CPP is 1,3bis(p-carboxyphenoxy)propane, GLUPHE is Ncarbobenzoxy-L-phenylalanyl-L-glutamic acid. Isolation of the polymer using an insoluble acid acceptor is preferred over the two phase solvent separation method since high boiling point solvents such as DMF or toluene do not have to be removed at ambient temperature to avoid decomposition of the formed polyanhydride. In contrast to the traditional use of dehydration agents, the use of insoluble acid acceptors such as poly(4-vinylpyridine) or inorganic bases yield highly pure polymers. The use of various solvent systems is complementary to the use of the insoluble bases in chloroform. The choice of the right solvent system can be used to precipitate exclusively either the polymer or the amine-acid salt, using filtration to yield pure polymers. These methods are advantageous for the polymerization of heat sensitive dicarboxylic acids such as therapeutically active diacids and polyanhydrides of dipeptides. |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |