DE1807497A1 - Optically active poly-beta-amides for fib - res and foils - Google Patents

Abstract

The polyamide has units of formula: -(HNCR1RCHR2CO)n-(where R and R2 are H, alkyl, alkenyl, aryl, R, is alkyl, alkenyl or aryl, R1 and R2 can form together an (unsat) cycloaliphatic gp with not more than 10C, n is 300 - 50,000 pref. 300-10000) in the main chain. The polyamide is pref. prepd. by polymerising a lactam of formula: The polymers have high melting pts. and low stability. The fibres and foils have high tearing and twisting coefficients.

Description

"Optically active poly-ß-amide" High molecular weight, optically active polyamides with centers of chirality in the main chain were previously only in the series of α-polypeptides accessible via Teuchs' anhydrides (E.R. Blout and A. Asadourian, J.Am. Chen. Soc. 78, 955 (1956)). In contrast, the polymerization of an optically active lactam, des d - (-) - ß-methyl - # - caprolactam, only to low molecular weight products, their degree of polymerization for technical processing, e.g.

for the production of fibers and foils, is not sufficient (C.G.

Overberger, H. Jabloner, J. polyen. Sci. 55, 32 (1961)).

The present invention relates to optically active poly [beta] amides with centers of chirality in the main chain with recurring units of the formula I in which R and R "denote hydrogen, an alkyl, alkenyl or aryl radical and R 'an alkyl, alkenyl or aryl radical, where R' and R" together can also be components of a cycloaliphatic, optionally unsaturated ring, all hydrocarbon radicals together should not have more than 10 carbon atoms and n has a value between 300 and 50,000, preferably 300 to 10,000. The optically active poly-ß-amides according to the invention are produced by processes known per se, by polymerization of ß-lactams of the general formula II, in which R, R 'and R "have the meaning given under formula I.

Optically active poly-β-amides according to the invention can advantageously be used Use for the production of foils, threads or moldings that have higher melting points and lower solubilities - the threads also have higher tensile strength and elongation at break -compared to those that are made of optically inactive material. Even when using mixtures of the optically active poly-β-amides according to the invention with optically inactive forms, the mentioned particularly advantageous properties become obtained, which is not the case when using the optically inactive polymers alone is.

Monomers suitable for polymerization are e.g .: (+) - 4-methyl-azetidinone, (-) - 4-Isopropyl-azetidinone, (+) - 4-vinylazetidinone, (-) - 4-phenyl-azetidinone, (+) - 4-methyl-4-propyl azetidinone, (-) - cis-3,4-dimethyl-azetidinone, (+) - trans-3,4-dimethyl-azetidinone, (-) - 4-methyl-4-neopentyl-azetidinone, (-) - 4-decyl-azetidinone, (+) - trans-3,4-dimethyl-4-propyl-azetidinone, (+) - 4-vinyl-4-methyl-azetidinone.

Optically active polycyclic β-lactams are also suitable, for example:

which may contain additional centers of chirality.

Of the optically active β-lactams mentioned for example, can the optical antipodes are also polymerized in the same way.

Optically active ß-tactams can also be optically active with any other active or racemic ß-lactams as well as with ß-lactams without centers of chirality and copolymerized with W; -pyrrolidone.

You can @ahlweise copolymers with blocked or random Obtained monomer sequence if, for example, an optically active lactam either alternately or added dropwise to the catalyst solution at the same time as another lactam component.

The polymerization can be anionic or cationic by known processes or hydrolytically catalyzed. Anionic polymerization is advantageous, because they reach the highest degrees of polymerisation in a short time at low temperatures leads. It is also possible to set the rate and degree of polymerization by adding chain starters, e.g.

Acyl lactams, acylating agents, inorganic acid chlorides or carbon monoxide, as well as by adding chain terminators such as water, alcohols, To influence amides or CH-acidic compounds.

The anionic polymerization proceeds when such bases are added are generally suitable as catalysts for lactam polymerization, e.g. potassium hydroxide, Sodium cyanide, lithium carbonate, sodium phenolate, tetra-benzylammonium hydroxide, pyrrolidone potassium, Alkali compounds of ß-lactams, such as the potassium salt of (-) - 4-methyl-azetidinone.

The polymerization can take place in the presence or absence of inert solution and diluents can be carried out. Polymerization is particularly advantageous in strongly polar solvents such as dimethyl sulfoxide, dimethylformamide or o-dichlorobenzene.

The lactams or their solutions can be mixed with other inert solvents can be combined so that two-phase monomer Mixtures arise. Emulsifying agents can be added to the polymerization mixture. Also direct polymerization to spinnable polymer solutions is possible, e.g. in solutions of lithium chloride or lithium fluoride in dimethylfornamide.

The degree of polymerisation is at values at which the properties, like melting point, solubility and degree of crystallinity change with increasing chain length practically no longer change, which is the case from approx. 300 monomer units. The upper The limit of the degree of polymerization is more difficult to measure here, since a molecular weight determination is not possible in the few possible solvents. By analogy to the molecular weight-viscosity relationship of the polymeric 4,4-dimethyl-azetidinone it can be deduced that the highest degrees of polymerization achieved here are well over 10,000 must lie. Such polymers can also be converted into fibers from the solution and process foils. The degree of polymerization is essential for technical usability between 300 and 10,000 best suited because the high solution viscosities are higher make processing from concentrated solutions difficult, while Below this Range the viscosity of the spinning solutions for processability oit already is too low.

Poly-B-amides made from optically active f '- lactams generally melt higher and are less attacked by solvents than the polymers of the racemates.

Mixtures of an optically active form with its racemate also result to polymers that have advantageous properties. For example, you get from 90, ig optically pure (-) - 4-methylazetidinone a polymer that the crystal lattice of the re @ en optically active polymer. It melts 43 .higher than the racemic one Polymers and, in contrast to this, is insoluble in conc. Sulfuric acid. It leaves are processed from formic acid into foils and threads.

The processing of the high-melting, optically active poly - @ - amides into threads, fibers and moldings is made from solution in strongly polar Solvents according to the known poly-B-amide spinning process.

The poor solubility of these polymers generally necessitates their use pronounced polyamide solvent, such as formic acid, dichloroacetic acid, trifluoroacetic acid, Fluoroal hydrate, conc. Nitric acid or mixtures of formic acid and boron trifluoride, equimolar amounts of which form a complex compound with one another The high melting ranges these poly-B-amides make them particularly suitable for the production of heat-resistant materials Textiles and for use in space and rocket technology.

The optically active poly-B-amides can also be mixed with others Polymers, especially in a mixture with other optically active or inactive ß-lactam polymers, processed from solution or melt; they can stand alone or in modified form Form due to its selective adsorption capacity for enantiomeric compounds also as carrier substances for the chromatographic or electrophoretic separation of enantiomers be used.

A few of the optically active poly-ß-amides, their monomer unit is substituted by more than three aliphatically bonded carbon atoms, soften already at 150-200 ° C. They are largely X-ray amorphous, soluble in methanol and can be lost hot without the addition of solvents. By melting, dry or In the case of spiders, clear threads are obtained from such polyamides; one can opt out of them Produce active glasses, in particular they are suitable for producing optically active glasses Fiber optics.

Example 1: a) Polymerization and properties of pure suspension of 2 g of potassium hydroxide in 400 ml of dimethyl sulfoxide is mixed with a solution of 6 g of polypropylene dimethyl sulfamide (corresponding to attached patent 789 641) in 800 ml heavy petrol with a boiling point of 160 - Mix well at 1800C. Dripping with continued stirring one within from 2 hours at 20-25 ° C 200 ml (-) - 4-methylazetidinone (# D21 = -8.22 ° in substance) to. The mixture is stirred for a further 2 hours and filtered off with suction. The filter cake is washed with methylene chloride and removes adhering solvents by steam distillation. After this Drying gives 198 g of polymer which melts at 3820C with decomposition. The material is insoluble in conc. Sulfuric acid, swells in formic acid and dissolves in dichloroacetic acid. A 1O solution in dichloroacetic acid is poured on glass plates to form films, which are dried at 40 ° C in a vacuum.

They can be detached from the glass plate by placing them in water.

Mixtures of (-) - 4-methylazetidinone are polymerized in the same way with the racemic form with the following optical purities 90% 80% 75% 70% 60 5 '50 % 25% Racemate (0%) The properties of these polymers are shown in Table 1.

With increasing optical purity, the melting point rises sharply, the solubility does not decrease and new reflections appear in the X-ray diagram. The solution viscosity remains pretty constant.

Figure 1 shows the specific rotation # D26 of the polymers in 1% Solution in dichloroacetic acid, the optical rotation being a linear function of the optical purity [in E is.

The melting temperature as a function of the optical purity of the polymer Fig. 2 shows; from it comes the strong rise in the melting point of the polymers with more than 50% optical purity.

Pure (+) - @ -Methyl-azetidinone is polymerized in a similar way or its mixtures with the racemate, completely analogous results are obtained. The products of both series differ only through the opposite optical rotation.

An optically inactive film, but the X-ray structure of the two possesses enantiomeric polymers, if one has equal amounts of the (+) - polymer and the (-) - polymer dissolves together in dichloroacetic acid, which dissolves on glass plates potted and dried in vacuum.

Table 1 Properties of polymers made from levorotatory and racemic 4-methyl-azetidinone Optical m.p. solubility in Purity (° C) conc. H2SO4 HCOOH Cl2C-COOH # rel. *) X-ray lattice distances # (%) 100 382 insol. swells sol. 4.2 9.81 - - 4.24 strong 90 374 insol. soluble soluble 5.09 - - - - 80 374 sol. Sol. Sol. 3.92 - - - - 75 374 sol. Sol. Sol. 5.53 9.58 - - 4.23 70 374 sol. Sol. Sol. 5.24 9.88 5.07 - 4.36 60 374 sol. Sol. Sol. 6.01 9.99 5.13 - 4.37 50 349 sol. Sol. Sol. 5.98 9.73 5.21 - 4.35 25 333 sol. Sol. Sol. 5.11 - 5.21 - 4.37 0 330 sol. Sol. Sol. 6.02 - 5.47 4.72 4.37 *) measured on 1 g of substance in 100 ml of dichloroacetic acid at 20 ° b) spinning A solution of 10 parts by weight of 90 ß optically pure (-) - 4-methyl-azetidinone polymer with a relative viscosity of 5.09 (measured on a solution from 0.1 g of polymer in 10 ml of dichloroacetic acid at 20 ° C) in 90 parts by weight of 98% formic acid is spun through a gold / platinum nozzle with 60 holes and 70 / u in an aqueous precipitation bath containing 10% sodium chloride. The spinning solution has a viscosity of 62 falling ball seconds (falling distance 20 cm, 20 ° C., steel balls # 2.5 mm). The precipitation immersion stretch is 140 cm long.

The spinning solution is drawn from an autoclave under nitrogen pressure of 0.7 atn. conveyed to the nozzle via spinning pump and spinning bow. That from the nozzle emerging thread bundle is at a speed of 4.0 m / min through the precipitation bath guided and deducted via Walzentrios. Then the thread is put into a 110 cm long water bath and withdrawn from the washing bath at 12 m / min. The salt-free The thread is then pulled over 25,000 hot block heaters at 15 m / min and after preparation wound up. A thread spun in this way has a tensile strength of 3.0 g / den, 20.2% elongation at break.

A thread spun under the same conditions from a racemic Poly-4-methyl-azetidinone has a tear strength of only 2.4 g / den and one Elongation at break. of only 14.8%. Due to their good temperature resistance, they are suitable the threads of the q table active polymer especially for the production of textile materials, exposed to high temperatures.

Example 2: 25 g of (+) - cis-3,4-dimethyl-azetidinone # D20 = 7.14 ° are dissolved (2.59% in methanol) in 100 ml of dimethyl sulfoxide. The solution is added while cooling at 16 ° C with 0.5 g of pyrrolidone potassium. The approach solidifies within 0 minutes into a gel that is ground with water after 3 hours. After vacuuming and drying Inan contains 24 g of polymer. 5 g of the same are stirred with 95 ml 98 pointer nitric acid. After about 30 minutes, the homogeneous solution is poured onto glass plates into films that are dried in vacuo at 20 ° C. Dissolve by soaking in water clear, colorless, tough films from the glass plate, which in formic acid and conc. Sulfuric acid are insoluble. The relative viscosity of a 1% solution of the polymer in 98% nitric acid is 87 after a dissolution time of 48 minutes. It takes slowly when standing (see upper degradation curve in Fig. 3). Other solvents from which the optically active polymer can be processed are antimony trichloride and an equimolar mixture of boron trifluoride and formic acid.

If the racemic cis-3,4-dimethyl-azetidinone is polymerized in the same way, in this way a polymer is obtained which has the same lattice spacing as the optical one active polymers. However, in contrast to these, it dissolves in conc. Sulfuric acid. Table 2 shows a comparison of the properties of the optically active and the racemic Product. Its solution in 98% nitric acid has a lower viscosity and becomes quick degraded, so that no usable foils from it under comparable conditions can be obtained.

FIG. 3 shows the decrease in viscosity of the solutions from 1 over time g optically active (upper curve) or 1 g racemic (lower curve) polymer in 100 ml of 98% nitric acid at room temperature.

Table 2 Optical solubility in X-ray grating Purity conc. H2SO4 conc HNO3 #spec. stands C o I ~~~~~ ~~~~~~~~~ FA insoluble sol. 94.0 6.22 4.46 O sol. Sol. 3.7 6.23 4.46 Example 3: 12 ml (-) - trans-3,4-dimethyl-azetidinone # D21 = -74.7 ° (3.0% in water) are added to a suspension of 0.25 g pyrrqlidone-potassium in 50 nl Dimethyl sulfoxide run in rapidly with cooling at 20 ° C. After 3 hours, the gel-like reaction mass is ground with water, filtered off with suction and dried. In receives 12 g of polymer.

A 5% solution of the polymer in trifluoroacetic acid rotates the plane of vibration polarized light.

The solution is poured onto a glass plate to form films, which one dried in vacuo at 30 ° C. When soaked in water, colorless, clear, tough foils from the glass plate. In contrast to the films of the racemic polymer are these foils from conc.

Sulfuric acid and formic acid not dissolved. In Table 3 are some Properties of the optically active and racemic polymer compiled.

The optically active polymer decomposes at temperatures around 460 ° C gradually to gaseous products without melting or discoloring. It is therefore particularly suitable as a heat shield or thermal insulation material for nozzle units and in space travel, as well as for the production of heat-resistant textiles.

Table 3 Optical solubility in Purity conc. HCOOH conc. HNO3 melting point (° C) (%) H2SO4 100 insoluble insoluble sol.> 460 O sol. Sol. Sol. 349 Example 4: 20 g of optically active (+) - 4-methyl-4-n-propyl-azetidin-2-one *) are dissolved together with 0.00448 g of oxalyl-bis-pyrrolidone in 120 ml of dimethyl sulfoxide. Then 40 ml of dimethyl sulfoxide are distilled off under reduced pressure to remove moisture. At a temperature of 20 ° C., 0.6 pyrrolidone potassium is added. The onset of polymerization is only slightly exothermic. The temperature is kept at 20.degree. C. for 4 hours. Then one falls the pole,: lere, by one dic. Poured highly viscous, clear solution into water. The polymer is washed and dried. 16.4 g of a polymer with a relative viscosity of 5.2 (measured on a solution of 1 g of polymer in 100 ml of concentrated sulfuric acid at 20 ° C.), which is largely amorphous and dissolves in methanol and chloroform, are obtained. The softening range of the amorphous material is very broad, about 160 - 20,000; the product can be pressed at higher temperatures to form optically active glass bodies or processed from solution or from the melt into clear films or threads. The optical activity was determined on the solution of 2.6 g of polymer in 100 ml of methanol at 25 ° C.: # D25 = + 18.85.

*) Rotation value of the monomer # D24 = + 11.1 ° (2.6% in methanol)

Claims (4)

Claims: 1. Optically active poly-ß-amides with centers of chirality in the main chain, with recurring units of the formula 1 in which R and R "denote hydrogen or an alkyl, alkenyl or aryl radical and R 'denotes an alkyl, alkenyl or aryl radical, where R' and R" together can also be components of a cycloaliphatic, optionally unsaturated ring , all hydrocarbon radicals together do not have more than 10 carbon atoms and n has a value of 2, between 300 and 50,000, preferably 300-10,000. 2. A process for the preparation of optically active poly-B-amides with centers of chirality in the main chain, characterized in that B-lactams of the general formula II in which R and R "denote either hydrogen or an alkyl, alkenyl or aryl radical and R 'denotes an alkyl, alkenyl or aryl radical, where R' and R" together are also components of a cycloaliphatic, optionally unsaturated ring can and all hydrocarbon radicals together do not have more than 10 carbon atoms, polymerized. 3. Obscuration of optically active poly-ß-anides with recurring units of the general formula I with centers of chirality in the main chain for production of foils, threads or moldings with higher melting points and lower Lö assets, with the Threads also have even higher tear strengths and elongation at break, compared to those made of optically inactive material. 4. Use of mixtures of optically active poly-ß-amides with optically inactive molds for the production of foils, threads or moldings with higher Melting points and lower solubilities, with the threads also being even higher Tear strengths and elongation at break show, compared to those from optically inactive Material alone.