DE1595711A1 - Process for the production of high molecular weight polybenzimidazoles or polybenzoxazoles - Google Patents

Description

Process for the production of high molecular weight polybenzimidazoles or Polybenzoxazoles It is known that trivalent organic compounds that at least contain two amino groups and one hydroxyl group in o-position to an amino group, reacted with aromatic dicarboxylic acid dihalides to form high molecular weight substances can be. Such asymmetric, trivalent organic compounds are for example 3-hydroxy-4,4'-diaminodiphenyl ether, 3-hydroxy-4, 4'-diaminodiphenyl sulfone and 4-hydroxy-3,3'-diaminodiphenyl sulfone, By polycondensation of these trivalent aromatic compounds with Di c arbonsäuredihal Polyamides are obtained which are in o-position to one amide group each Structural unit still carry a hydroxyl group, which then in the second phase to polybenzoxazoles can be converted. is also known, polybenzimidazoles and polybenzoxazoles to produce, for example, from 3-hydroxy-4-aminobenzhydrazide and Dicarboxylic acid dichlorides are produced in which the ring closure is achieved by annealing to the oxdiazole is carried out.

A process for the preparation of high molecular weight polybenzimidazoles or polybenzoxazoles has now been found if asymmetrically substituted primary aromatic amines of the formula wherein Ar1 and Ar are aromatic ring systems, the substituent R, which is in o-position to the amino group, is an -OR1 or HR2 group, R1 is hydrogen or a C1-C4-alkyl radical, R2 is hydrogen, a C1-C4-alkyl radical or a optionally substituted aryl radical and X is one or more heterocyclic ring systems, optionally condensed with the aromatic rings Ar and / or Ar1, in a polar solvent at temperatures between -30 and +150 0C with aromatic dicarboxylic acid dihalides of the formula ZOC-Ar2-COZ, wherein Z Chlorine or bromine and Ar2 is a divalent aromatic radical, and the polymer obtained is then heated to temperatures above 200 ° C.

Polyamides are formed from the following structural units: here R = OR1 (R1 = H or 01-C4 alkyl) or (R2 = H, C1-C4 alkyl or an aromatic radical which can optionally be substituted) and X is one or more, optionally with the aromatic rings Ar una / or Ar1 condensed heterocyclic ring systems with 1 to 3 heteroatoms and Ar2 a bifunctional aromatic radical.

The polycondensation is preferably carried out in polar organic solvents, such as N, N-dialkylic acid amides, or N-substituted lactams, such as, for example, dimethylacetamide or N-methylpyrrolidone. The great advantage of these solvents is that one can work in the absence of additional acid acceptors.

If the acid halide and the trivalent aromatic compounds listed above are used in equivalent amounts, highly viscous polyamide solutions are formed which can be processed into films and threads at temperatures of 50 to 200 oC. The condensation itself is carried out at temperatures between -30 and +150 ° C, preferably between -10 and +30 ° C. The solids content of the solutions is 5 to 40%, preferably 15 to 25%. In the case of the films and foils produced from these solutions, the ring closure to the polybenzimidazole or polybenzoxazole can then take place in the second stage at temperatures above 200 ° C., preferably above 250 ° C. Polymers of the following structural unit are obtained: (Y = -0- or ZNR with R = H, aryl or C1-C4 alkyl; X = one or more heterocyclic ring systems, which can optionally be fused with the aromatic rings Ar1 and / or Ar; Ar2 = bifunctional aromatic radical).

If you choose temperatures from the outset when producing the films and threads above 300 ° C., the ring closure already occurs under these processing conditions to polybenzoxazole or polybenzimidazole.

Draw the films, threads and fibers made in these ways is characterized by an extremely high temperature resistance.

The polyamides are made from trivalent aromatic compounds with the following structure in which the two substituents NH2 and R of the aromatic ring system Ar must be in the o-position to one another, and aromatic dicarboxylic acid dihalides of the general formula Z-CO-Ar2-CO-Z, where Z is halogen and Ar2 is a divalent aromatic radical.

The following compounds are examples of dicarboxylic acid dihalides suitable: diphenyldicarboxylic acid dichloride-4,4 ', naphthalenedicarboxylic acid dichloride-1.5, Isophthalic acid dichloride, terephthalic acid dichloride and the corresponding dibromides as well as alkyl and halogen substitution products of the listed acid halides.

The following trivalent aromatic compounds are suitable for polycondensation: where X = -O-, -S- or NR1 with R1 = H, C.1-4 alkyl or aryl, y = OR2 or -NHR3 with R2 = H or C1-C4 alkyl, R3 = H, aryl or C1- Can be C4 alkyl. where X = -O-, -S- or) NR1 with R1 = H, aryl or C1-4 alkyl y = OR2 or NHR3 with R2 = H or C1-C4 alkyl R3 = H, aryl or C1-C4 alkyl . with X = -O-, -S- or> NR1 (R1 = H, aryl or C1-C4 alkyl) y = -OR2 or - NHR3 (R2 = H or C1-C4 alkyl, R3 = aryl, C1-C4 alkyl ) where X = -O-, -S-, with R1 = H, aryl or C1-C4 alkyl y = -OR2 or NRR3 with R2 = H or C1-C4 alkyl R3 = H, aryl or C1-C4 alkyl. with y = -OR1 or -NHR2, where R1 = H or C1-C alkyl, R2 = H, aryl or C1-C4 alkyl.

Instead of the trivalent aromatic oxdiazoles, the corresponding diacylhydrazines, for example (with X = -OR1 or -NHR2, where R1 = H or C1-C4 alkyl, R2 = H, aryl or C1-C4 alkyl) can be used.

The ring closure to the oxdiazole then takes place in the second phase in the polymer at temperatures above 200 ° C.

The trivalent ones preferably used for the preparation of the polymers aromatic compounds that have a 1,3,4-oxdiazole as a heterocyclic ring system or N-substituted 1,2,4-triazole ring can be, for example in the following way. m- or p-Nitrobenzoylhydrazid is in the presence of Acid scavengers such as alkali hydroxyl, carbonate or pyridine with 4-methoxy-3-nitro, 3-methoxy-4-nitro, 4-chloro-3-nitro or 3-chloro-4-nitrobenzoyl chloride to the asymmetrically substituted Dibenzoylhydrazines implemented. With cyclizing agents such as SOC12 or POCl3 then the ring to the oxdiazole is closed. In the products where themselves if a chlorine atom is o-position to a nitro group, this can be converted into dimethylformamide or N-methylpyrrolidone at temperatures between 80 and 130 ° C., preferably 100 up to 120 ° C, replace with -NHR (with R = H, C1-C4 alkyl or aryl).

At temperatures of 160 to 220 ° C, preferably 170 to 190 ° C, the 1,3,4-oxadiazoles can be converted into the N-substituted 1,2,4-triazoles with amines convict. The resulting dinitrodiphenyloxdiazoles or N-substituted dinitrodiphenyltriazoles, those in the o-position to a nitro group or a methoxy, amino, alkylamino or Carrying arylamino groups are then converted into the trifunctional by hydrogenation of the nitro groups transferred to aromatic compounds.

Example 1 a) 210 parts by weight of 3-nitrobenzoyl hydrazide and 290 parts by weight of 3-nitro-4-methoxy-benzoyl chloride in 1,400 parts by weight of pyridine and heated under reflux for 5 hours. The solution is after cooling to room temperature stirred into approx. 5,000 parts by volume of water. The deposited precipitate is Aspirated and washed out several times with water. After drying, 406 parts by weight are obtained = 97% of theory 3,3'-dinitro-4-methoxydibenzoylhydrazine. The almost colorless connection melts at 230 to 236 OC. b) 460 parts by weight of 3,3'-dinitro-4-methoxydibenzoylhydrasine were refluxed in 3,000 parts by weight of phosphorus oxychloride for 24 hours. the The solution is then poured onto ice while it is still hot and the precipitate which has separated out is filtered off with suction.

It is washed several times with water, sodium hydrogen carbonate solution and at the end again with water and, after drying, obtains 350 parts by weight = 83 * The theory 3,3'-Dinitro-4-nethoxydiphenyloxdiazole (1,3,4). The melting point of the almost colorless compound is between 203 and 205 OC. c) 450 parts by weight of 3,3'-dinitro-4-methoxydiphen; yloxdiaeol (1, 3, 4) are added in 1,800 parts by weight of dimethylformamide with the addition of 80 parts by weight Raney nickel at temperatures of 50 to 60 ° C and a hydrogen pressure of 40 Catalytically hydrogenated up to 60 atmospheres. The Raney nickel is removed by eyes and the solution in water stirred in. 350 parts by weight are obtained = 94% of theory 3,3'-diamino-4-methoxydiphenyloxidazole (1,3,4). After recrystallization from dioxane, the melting point of the compound is 189 to 192 ° C.

Analysis C H O N Calculated 64.0% 4.9 ffi 11.4 * 19.9% Found 63.8 ffi 5.1 * 11.7% 20.0 * a) In 700 parts by weight of dry N-methylpyrrolidone 141 parts of 3,3'-diamino-4-methoxydiphenyloxdiaxol (1,3,4) were dissolved. Under vigorous Stirring, 101.5 parts by weight of isophthalyl chloride are then slowly added at 0 to 5 ° C. When the addition is complete, the clear, highly viscous solution is allowed to come to room temperature come and stir for 5 hours. Pipes can be spun directly from this solution and produce films that after heating to temperatures above 250 ° C. in solvents are no longer soluble. The softening point of the polymers is 325 ° C.

Example 2 a) 380 parts by weight of 4-nitrobenzoyl hydrazide are as in Example 1 a) described with 525 parts by weight of 3-nitro-4-methoxybenzoyl chloride in 2500 parts by weight of pyridine reacted. There are 745 parts by weight = 98 ffi of theory 3,4'-Dinitro-4-methoxydibenzoylhydrazine was obtained. The melting point of the colorless Connection-lies at 230 to 233 ° C. b) 385 parts by weight of 3,4'-dinitro-4-methoxydibenzoylhydrazine are added to 3,200 parts by weight of thionyl chloride and refluxed for 24 hours. The reaction product partially precipitates out during the reaction. The slurry is poured on ice, sucks off the precipitate and washed thoroughly with water, sodium hydrogen carbonate solution and water out.

There are 305 parts by weight = 82 * of theory 3, 4'-dinitro-4-methoxydiphenyloxdiazole (1,3,4) obtained from melting point 240 to 245 ° C. c) 290 parts by weight of 3,4'-dinitro-4-methoxydiphenyloxdiazole (1,3,4) are in 900 parts by weight of dimethylformamide with the addition of 55 parts by weight Raney nickel at temperatures from 50 to 60 ° C and pressures from 40 to 60 atmospheres catalytic hydrated. Since the reaction product partially precipitates on cooling, the warm solution is freed from Raney nickel by suction and the diamine with Water precipitated. After recrystallization, 197 parts = 82% of the theory 3,3'-diamino-4-methoxydiphenyloxdiazole (1,3,4) obtained. The colored substance melts at 229 to 233 ° c.

Analysis C H O N Calculated 64.0 ffi 4.9 * 11.4% 19.9% Found 63.7% 5.0% 11.8% 19.3% d) 141 parts by weight of 3,4'-diamino-4-methoxydiphenyloxidazole (1,3,4) are dissolved in 700 parts by weight of dry N-methylpyrrolidone. At O to At 5 ° C., 101.5 parts by weight of isophthalyl chloride are then slowly increased with vigorous stirring admitted. The clear, highly viscous solution is then slowly allowed to reach room temperature come. After one hour the solution is so highly viscous that another 200 parts by weight dry N-methylpyrrolidoin must be added. Nan leaves another 4 hours stir. Films and threads can be produced directly from the solution obtained that are no longer in solvents after heating to temperatures above 250 ° C are soluble. The softening point of the polymers is 325 ° C.

Claims (3)

Claims 1. Process for the production of 3enzimidazole or Polymers containing benzoxazole ring systems, characterized in that asymmetrically substituted primary aromatic amines of the formula wherein Ar1 and Ar are aromatic ring systems, the substituent R, which must be in the o-position to the amino group, an -OR1 or -NHR2 group, R1 is hydrogen or a C1-C4-alkyl radical, R2 is hydrogen, a C1-C4-alkyl radical or an optionally substituted aryl radical and X is one or more heterocyclic ring systems, optionally condensed with the aromatic rings Ar and / or Ar1, in a polar solvent at temperatures between -30 and +150 ° C with aromatic dicarboxylic acid dihalides of the formula ZOC-Ar2-COZ, where Z is chlorine or bromine and Ar2 is a divalent aromatic radical, and the polymer obtained is then heated to temperatures above 200.degree. 2. Ancestors according to claim 1, characterized in that mon as polar solvent N, N-dimethylacetamide or N-methylpyrrolidone is used. 3. Polymers of structure where y is oxygen or the> NR group, R is hydrogen, a C1-C4-alkyl radical or an aryl radical which may optionally be substituted, Ar and Ar1 are aromatic ring systems, Ar2 is a bifunctional aromatic group, X is one or more, optionally with the aromatic ones Rings Ar and / or Ar1 are fused heterocyclic ring systems and n is an integer greater than 5.