Composition made of amino acid or ester with polymer quality and methods for obtaining same

Abstract

The present invention relates to a composition which comprises at least one ,-amino-alkanoic acid or ester and at least one alkanoic ester or acid, characterised in that: the ,-amino-alkanoic acid or ester has formula H.sub.2N(CH.sub.2).sub.n-COOR, wherein n=9 to 13 and R is an alkyl group or a hydrogen; the alkanoic ester or acid has formula R.sub.1COOR.sub.2, wherein R.sub.1 is a straight or branched alkyl group with formula C.sub.mH.sub.2m+1 or C.sub.mH.sub.2m3, wherein m=6 to 20 and R.sub.2 is an alkyl group or a hydrogen; the molar ratio between the alkanoic acid(s) or ester(s) and the ,-amino-alkanoic acid(s) or ester(s) is in the range from 0.001 to 0.4%. The present invention also relates to novel methods for obtaining such a composition.

Claims

1. A composition comprising at least one ,-aminoalkanoic acid or ester and at least one alkanoic acid or ester, wherein: the ,-aminoalkanoic ester or acid has the formula H.sub.2N(CH.sub.2).sub.nCOOR with n=9 to 13 and R is an alkyl group or a hydrogen, the alkanoic acid or ester has the formula R.sub.1COOR.sub.2 with R.sub.1 being a linear or branched alkyl group of formula C.sub.mH.sub.2m+1 or C.sub.mH.sub.2m1 or C.sub.mH.sub.2m3 where m=6 to 20 and R.sub.2 is an alkyl group or a hydrogen, the molar ratio between alkanoic acid(s) or ester(s) and ,-aminoalkanoic ester(s) or acid(s) is in the range of from 0.001% to 0.4%.

2. The composition as claimed in claim 1, wherein n=10 or 11, and R is a methyl or ethyl or butyl group or a hydrogen.

3. The composition as claimed in claim 1, wherein R.sub.1 is a linear alkyl group of composition C.sub.n1H.sub.2n1 and R.sub.2 is a methyl or ethyl group or a hydrogen.

4. The composition as claimed in claim 1, wherein the molar ratio between alkanoic acid(s) or ester(s) and ,-aminoalkanoic ester(s) or acid(s) is in the range of from 0.01% to 0.2%.

5. The composition as claimed in claim 1, wherein it also comprises an acid nitrile or a nitrile ester of formula NC(CH.sub.2).sub.(n1)COOR, in which the molar ratio of nitrile relative to the ,-aminoalkanoic ester or acid is in the range of from 0.0001% to 0.5%.

6. The composition as claimed in claim 1, wherein it also comprises a secondary amine of formula ROOC(CH.sub.2).sub.nNH(CH.sub.2).sub.nCOOR, in which the molar ratio relative to the ,-aminoalkanoic ester or acid is in the range of from 0.0001% to 1%.

7. The composition as claimed in claim 1, wherein it also comprises ROOC(CH.sub.2).sub.nNHCO(CH.sub.2).sub.nNH.sub.2 dimer, the molar ratio of dimer relative to the ,-aminoalkanoic ester or acid being in the range of from 0.0001% to 5%.

8. The composition as claimed in claim 1, wherein it also comprises at least one compound chosen from: compounds that are inert with respect to the polymerization, alcohols, water, and mixtures thereof.

9. The composition as claimed in claim 8, wherein the compounds that are inert with respect to the polymerization are chosen from: aromatic hydrocarbons; aliphatic hydrocarbons; an aliphatic fraction; an ether; and mixtures thereof.

10. The composition as claimed in claim 8, wherein the alcohols are chosen from methanol, ethanol, butanol, and mixtures thereof.

11. The composition as claimed in claim 8, wherein the content of inert compounds, of alcohol and/or of water is less than 90%, by weight relative to the total weight of the composition.

12. The composition as claimed in claim 1, wherein the content of ,-aminoalkanoic ester or acid is greater than 10%, by weight relative to the total weight of the composition.

13. A polymer, in particular polyamide, obtained by polymerization of the composition of claim 1, wherein the degree of polymerization thereof is greater than 80.

Description

EXAMPLES

Example 1: Preparation of a Composition According to the Invention

(1) Unsaturated nitrile ester methyl 10-cyano-9-decenoate (NEI11) is prepared by reacting methyl 9-decenoate with acrylonitrile according to example 5 of WO 2014/122410, followed by evaporation of the toluene and a distillation under reduced pressure so as to obtain NEI11 containing less than 100 molar ppm of methyl decenoate.

(2) 13.5 g of Raney cobalt washed with methanol (ActiCat 3100 from the company CatAlloy) and 90 g of NEI11 unsaturated nitrile ester and 210 g of toluene are placed in a 1-liter autoclave equipped with a self-suction turbine. The autoclave is flushed with nitrogen, then 4.3 g of ammonia (0.253 mol) are introduced and hydrogen is added so as to bring the pressure to 60 bar. Heating is carried out at 90 C. and the reaction is allowed to take place for 10 hours with vigorous stirring while at the same time maintaining the pressure at 60 bar by addition of hydrogen.

(3) The reactor is then cooled to ambient temperature and the pressure is lowered to atmospheric pressure. The solid is separated from the liquid phase and washed with toluene. The combined liquid phases are evaporated in a rotary evaporator at 30 C. at a pressure which is gradually lowered to 1 mbar. The residual liquid phase is analyzed by gas chromatography: it contains 96% of primary amine, 2.4% of secondary amine, 0.1% of methyl decanoate, 0.1% of saturated nitrile ester methyl 10-cyanodecanoate (NE11) and 1% of toluene (% by weights).

(4) This residual liquid phase is then continuously distilled in a scraped-film short-path evaporator of KDL4 type (UIC). The evaporator is maintained at a pressure of 0.7 mbar. The liquid to be distilled is fed at 150 g/h via the top of the evaporator and forms a film on the exchange surface heated to 120 C. by virtue of roll scrapers. The vapors are condensed on a central exchanger maintained at 15 C.

(5) A composition of methyl 11-aminoundecanoate (AE11) and of methyl decanoate (MD) in a 99.9/0.1 molar ratio is recovered. The weight content of AE11 in the composition is 98.9%, that of saturated nitrile ester methyl 10-cyanodecanoate (NE11) is 0.1%, that of secondary amine of formula (MeCO.sub.2(CH.sub.2).sub.10).sub.2NH is 0.01% and that of toluene is 0.5%. The molar yield of AE11 of the reaction and separation steps is 86%.

Example 2: Polymerization of the Composition Obtained in Example 1

(6) The composition of AE11 and of MD of example 1 (100 g), water (100 g) and 85% phosphoric acid (0.06 g) are introduced into a reactor at total reflux. The reaction mixture is brought to 110 C. for 90 minutes with vigorous stirring. The medium is then lyophilized (so as to remove the water and the methanol), then the lyophilisate is heated to 250 C. under nitrogen flushing in a glass reactor pre-inerted with nitrogen. After 0 h 30 of heating, the polymer obtained is cooled and then analyzed by proton NMR. The degree of polymerization is calculated on the basis of the NMR analysis: it is double the molar ratio between, on the one hand, the amide functions and, on the other hand, the sum of the chain ends (such as amine, acid, alkyl and ester functions).

(7) The melt rheology stability is measured by monitoring the change in the melt viscosity in plate-plate rheometry for 30 minutes at 270 C. The melt viscosity is determined at T0, then after 30 minutes, as is the percentage variation between the two.

(8) The results are reported in table 1.

Comparative Example 3

(9) Example 1 is reproduced with a Raney nickel catalyst (W. R. Grace and Co. Raney 2800 with a titer of more than 89% Ni). The results are reported in table 1.

(10) The residual liquid phase after evaporation of the toluene contains 95.5% of primary amine, 2.4% of secondary amine, 0.6% of methyl decanoate, 0.1% of saturated nitrile ester NE11 and 1% of toluene (% by weights).

(11) After distillation, a composition of AE11 and of MD in a 99.4/0.6 molar ratio is recovered. The weight content of AE11 in the composition is 98.4%, that of saturated nitrile ester methyl 10-cyanodecanoate (NE11) is 0.1%, that of secondary amine of formula (MeCO.sub.2(CH.sub.2).sub.10).sub.2NH is 0.02% and that of toluene is 0.5%.

Example 4: Polymerization of the Composition Obtained in Example 3

(12) The composition of AE11 and of MD of example 3 is polymerized in the same way as example 2 and the degree of polymerization and the melt rheology stability are measured. The results are reported in table 1.

(13) It is noted that the degree of polymerization is much lower than in example 2.

Comparative Example 5

(14) 302 g of commercial 11-aminoundecanoic acid (Sigma-Aldrich) in 1 liter of methanol are introduced into a 2-liter glass reactor equipped with a condenser. 30 normal liters per hour of anhydrous HCl are injected at 60 C. for 3 hours. The reaction mixture is then evaporated in a rotary evaporator under 0.2 bar at 35 and then 45 C. The solid is taken up in 2 liters of ethyl ether and then washed at 5 C. with 380 ml of aqueous 20% sodium hydroxide. After separation by settling out and setting aside of the aqueous phase, the organic phase is washed successively with 200 ml of aqueous 1% sodium hydroxide and then with 4 times 200 ml of demineralized water. The first aqueous phase is re-extracted with 500 ml of ethyl ether and the ethereal phase is washed successively with the aqueous phases previously obtained. The extraction operation is repeated again with 500 ml of ether. The combined organic phases are dried over magnesium sulfate and then evaporated in a rotary evaporator at 20-30 C. while gradually lowering the pressure to 1 mbar.

(15) The liquid phase recovered is continuously distilled in a scraped-film short-path evaporator in the same way as in example 1. A liquid phase more than 99.5% composed of AE11 and containing less than 1 ppm of alkanoic acids or esters is obtained.

Example 6: Polymerization of the Composition Obtained in Example 3

(16) The composition of AE11 containing less than 1 ppm of alkanoic acids or esters, produced in example 5, is polymerized in the same way as in example 2 and the degree of polymerization and the melt rheology stability of the polymer (polyamide 11) are measured.

(17) The results are reported in table 1.

(18) It is noted that the polymer is much less temperature-stable than that of example 2.

Example 7: Preparation of a Composition According to the Invention

(19) Unsaturated nitrile ester methyl 10-cyano-9-decenoate (NEI11) containing less than 100 molar ppm of methyl decenoate is prepared in the same way as in example 1.

(20) Silicone carbide (Sicat CTS-17 with a BET surface area of 24 m.sup.2/g and composed of more than 99% of -sic and less than 0.5% of Fe) is ground and sieved to a particle size of 0.1-0.2 mm, then oven-dried at 120 C. for 2 hours. A 20 g fraction of the powder obtained is subjected to incipient wetness impregnation, to the pore volume, with 11.4 ml of an aqueous solution of ruthenium III nitrosyl nitrate at 0.08 g of Ru ion per ml. The solid is then calcined under an air stream in a tube heated at 2 C./min up to 270 C. and maintained at this temperature for 4 hours.

(21) A part of the solid obtained (10 g) is placed in a fixed-bed reactor. The catalyst is reduced by treatment under hydrogen at 240 C. and then 4.8 normal liters per hour of a mixture of 3% by volume ammonia in hydrogen and 10 ml/h of a solution of methyl 10-cyano-9-decenoate at 30% by weight in toluene are injected. The reactor is maintained at a temperature of 80 C. and an expansion valve ensures a pressure of 50 bar inside the reactor. The liquid phase at the reactor outlet is recovered over a period of 70 hours. After evaporation in a rotary evaporator at 30 C. at a pressure which is gradually reduced to 1 mbar, a residual liquid phase is obtained, which is analyzed by gas chromatography: it contains 95% of primary amine, 3.6% of secondary amine, 0.27% of methyl decanoate, 0.1% of saturated nitrile ester NE11 and 1% of toluene (% by weights).

(22) This residual liquid phase is then distilled in a scraped-film short-path evaporator in the same way as in example 1.

(23) A composition of methyl 11-aminoundecanoate (AE11) and of methyl decanoate (MD) in a 99.73/0.27 molar ratio is recovered. The weight content of AE11 in the composition is 98.9%, that of saturated nitrile ester methyl 10-cyanodecanoate (NE11) is 0.1%, that of secondary amine of formula (MeCO.sub.2(CH.sub.2).sub.10).sub.2NH is 0.02% and that of toluene is 0.5%. The molar yield of AE11 of the reaction and separation steps is 85%.

Example 8: Polymerization of the Composition Obtained in Example 7

(24) The AE11 produced in example 7 is polymerized in the same way as in example 2 and the degree of polymerization and the melt rheology stability are measured.

(25) The result is reported in table 1.

Example 9: Preparation of a Composition According to the Invention

(26) Unsaturated nitrile ester methyl 10-cyano-9-decenoate (NEI11) containing less than 100 molar ppm of methyl decenoate is prepared in the same way as in example 1.

(27) Silicone carbide (Sicat CTS-17 with a BET surface area of 24 m.sup.2/g and composed of more than 99% of -sic and less than 0.5% of Fe) is ground and sieved to a particle size of 0.1-0.2 mm, then oven-dried at 120 C. for 2 hours. A 20 g fraction of the powder obtained is subjected to incipient wetness impregnation, to the pore volume, with 1.14 ml of an aqueous solution of cobalt II nitrate hexahydrate at 0.176 g of Co ion per ml. The solid is then calcined under an air stream in a tube heated at 5 C./min up to 400 C. and maintained at this temperature for 4 hours. It is then reduced under a hydrogen stream at 350 C. for 4 hours, then passivated at ambient temperature under a stream of air depleted to 0.1% oxygen, then to 1% oxygen.

(28) A part of the solid obtained (7 g) is placed in a fixed-bed reactor. The catalyst is reduced by treatment under hydrogen at 240 C. and then 4.8 normal liters per hour of a mixture of 3% by volume ammonia in hydrogen and 10 ml/h of a solution of methyl 10-cyano-9-decenoate at 30% by weight in toluene are injected. The reactor is maintained at a temperature of 80 C. and an expansion valve ensures a pressure of 50 bar inside the reactor. The liquid phase at the reactor outlet is recovered over a period of 70 hours. After evaporation in a rotary evaporator at 30 C. at a pressure which is gradually reduced to 1 mbar, a residual liquid phase is obtained, which is analyzed by gas chromatography: it contains 90% of primary amine, 5% of secondary amine, 0.12% of methyl decanoate, 0.1% of saturated nitrile ester NE11 and 1% of toluene (% by weights).

(29) This residual liquid phase is then distilled in a scraped-film short-path evaporator in the same way as in example 1.

(30) A composition of methyl 11-aminoundecanoate (AE11) and of methyl decanoate (MD) in a 99.88/0.12 molar ratio is recovered.

Example 10: Polymerization of the Composition Obtained in Example 9

(31) The AE11 produced in example 9 is polymerized in the same way as in example 2 and the degree of polymerization and the melt rheology stability are measured.

(32) The results are reported in table 1.

Example 11: Preparation of a Composition According to the Invention

(33) Unsaturated nitrile ester methyl 10-cyano-9-decenoate (NEI11) containing less than 100 molar ppm of methyl decenoate is prepared in the same way as in example 1.

(34) 10 g of palladium at 2% on reduced carbon powder (BASF Italy reference 51678063-5254) and 90 g of unsaturated nitrile ester NEI11 and 210 g of toluene are introduced into a 1-liter autoclave equipped with a self-suction turbine. The autoclave is flushed with nitrogen, then hydrogen is added so as to maintain a pressure of 5 bar. After eight hours with vigorous stirring at 30-40 C., the reaction medium is expanded and then filtered. Gas chromatography analysis shows that the NEI11 has been 97% converted.

(35) The liquid phase is again introduced into the autoclave containing 13.5 g of Raney nickel washed with methanol (W. R. Grace and Co. Raney 2800 with a titer of more than 89% Ni). The autoclave is flushed with nitrogen, then 4.3 g of ammonia (0.253 mol) are introduced and hydrogen is added so as to bring the pressure to 60 bar. Heating is carried out at 90 C. and the reaction is allowed to take place for 12 hours with vigorous stirring while at the same time maintaining the pressure at 60 bar by addition of hydrogen.

(36) The reactor is then cooled to ambient temperature and the pressure is lowered to atmospheric pressure. The solid is separated from the liquid phase and washed with toluene. The combined liquid phases are evaporated in a rotary evaporator at 30 C. at a pressure which is gradually lowered to 1 mbar. The residual liquid phase is analyzed by gas chromatography: it contains 96% of primary amine, 2.3% of secondary amine, 0.03% of methyl decanoate, 0.03% of saturated nitrile ester NE11 and 1% of toluene (% by weights).

(37) This residual liquid phase is then distilled in a scraped-film short-path evaporator in the same way as in example 1.

(38) A composition of methyl 11-aminoundecanoate (AE11) and of methyl decanoate (MD) in a 99.97/0.03 molar ratio is recovered.

Example 12: Polymerization of the Composition Obtained in Example 11

(39) The AE11 produced in example 11 is polymerized in the same way as in example 2 and the degree of polymerization and the melt rheology stability are measured.

(40) The results are reported in table 1.

Example 13

(41) A solution containing 2% by weight of heptanoic acid in methanol (5 grams) is sprayed onto 99.9 g of commercial powdered 11-aminoundecanoic acid (Sigma-Aldrich) with vigorous stirring. The methanol is then evaporated off under reduced pressure. A mixture of 11-aminoundecanoic acid containing 0.15 mol % of heptanoic acid is obtained.

Example 14: Polymerization of the Composition Obtained in Example 13

(42) The composition of 11-aminoundecanoic acid and heptanoic acid of example 13 (100 g), to which 85% phosphoric acid (0.06 g) has been added, is introduced into a glass reactor pre-inerted with nitrogen. The reaction mixture is brought to 250 C., under nitrogen flushing, with vigorous stirring. After 0 h 30 of heating, the polymer obtained is cooled.

(43) The degree of polymerization and the melt rheology stability are measured in the same way as in example 2.

(44) The results are reported in table 1.

(45) TABLE-US-00001 TABLE 1 Molar ratio Alkanoic Melt viscosity at 270 C. (Pa .Math. s) acid/ester Variation to Amino- Degree of over alkanoic poly- After 30 the course of Example acid/ester merization Initial minutes 30 minutes Example 2 0.1% 140 16 800 44 300 +164% Comparative 0.6% 70 620 1120 +80% example 4 Comparative <1 ppm 150 21 200 75 200 +254% example 6 Example 8 0.27% 120 4090 10 200 +149% Example 10 0.12% 135 15 900 41 300 +160% Example 12 0.03% 145 19 100 55 700 +192% Example 14 0.15% 145 17 200 45 800 +166%