CA2194189C - Process for producing cyclic lactames - Google Patents
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- CA2194189C CA2194189C CA002194189A CA2194189A CA2194189C CA 2194189 C CA2194189 C CA 2194189C CA 002194189 A CA002194189 A CA 002194189A CA 2194189 A CA2194189 A CA 2194189A CA 2194189 C CA2194189 C CA 2194189C
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Abstract
Production of cyclic lactames by reaction with water of aminocarboxylic acid compounds of general formula (I) in which R1 is -OH, -O-C1-C2-alkyl or -NR2-R3, R2 and R3 are mutually independently hydrogen, C1-C12 alkyl and C5-C8 cycloalkyl and m is a whole number from 3 to 12. The reaction is conducted in the liquid phase using heterogeneous catalysts.
Description
BASF Aktiengesellschaft 930746 O.Z. 0050/44982 ~1~~1$~
Preparation of cyclic lactams The present invention relates to a process for the preparation of cyclic lactams by reacting an aminocarboxylic acid compound of the general formula I
HaN - (CH2)m - COR1 I
where R1 is -OH, -0-C1-Clz-alkyl or -NRZR3 and Ra and R3, indepen-dently of one another, are each hydrogen, Cl-Ci2-alkyl or r C5-Cg-cycloalkyl and m is an integer from 3 to 12, with water.
US 3,485,821 relates to the uncatalyzed conversion of amino-caproic acid, aminocaproamide and alkyl-substituted derivatives thereof into caprolactam or alkyl-substituted caprolactam by carrying out the reaction in water at from 150 to 350°C, it being .
possible to add ammonium salts to the water. However, the convey- _., sions to caprolactam are not higher than 90 DE-A 2,535,689 describes a process for the preparation of capro lactam by converting 6-aminocaproic acid dissolved in methanol or ethanol, the solvent having an alcohol content of at least60 ~-by volume and the reaction being carried out at from 170 to 200°C.
According to DE-A 2,535,689, higher temperatures, in particular 220°C or higher, lead to the increased formation of the comes-ponding alkyl ester of 6-aminocaproic acid, which finally results in increased oliqomer formation. According to this document, water contents above 40 ~ by volume should lead to the formation. -of open-chain polyamides. For commercial use, the addition of the 6-aminocaproic acid is a considerable disadvantage since the aminocaproic acid should be completely dissolved before it is converted into caprolactam, and hence 6-aminocaproic acid must be constantly added-and its consumption monitored.
Ind. Eng. Chem. Process Des. Dev. ~(1) (1978), 9-16 (Mares et al.) describes the conversion of 6-.aminocaproic acid, both in water and in ethanol, into caprolactam without the addition of a catalyst. The yield of caprolactam in water at a reaction temperature of 211°C is only 65 ~, while yields of up to 98 ~ are _ said to be achievable in pure ethanol- Eiowever, the yields of 92 ~ or higher described by Mares et al. could not be_ repeated in our own experiments. Rather, these high yields can be explained-only by the fact that Mares et al. did not use a 10 ~ strength by °. BASF Aktiengesellschaft 930746 O.Z. 0050/44982 weight solution of 6-aminocaproic acid but cyclized minimum -6-aminocaproic acid concentrations to give caprolactam by contin-uous addition of 6-aminocaproic acid to the ethanolic solution. -Since caprolactam is-stable under the chosen reaction conditions, it was possible to obtain the high yields (92 ~ and 98 ~) only by virtue.of the fact that the concentration of caprolactam in-creased during the reaction. This assumption is supported by US 2,535,689 (with Mares as coinventor). Example 1 of this U.S.
patent indicates that a reaction of the 6-aminocaproic acid is to be prevented before the 6-aminocaproic acid has completely dis- -_ solved. For this purpose, the 6-aminocaproic acid should be added- -so slowly that no solid acid is present in the solvent but the 6-aminocaproic acid is dispersed virtually immediately in the hot solvent and is completely dissolved or is dispersed during heat-ing. Since the maximum solubility of 6-aminocaproic acid in both cold and boiling ethanol (78°C) is only 1.3 g/I (= 0.13 ~ by weight), it is clear that, in Mares et al.., 6-aminocaproic acid could be added only gradually in order to obtain a solution which, purely theoretically, contained 10 ~ by weight of 6-amino-caproic acid. Otherwise, the technicalprocedure for such meter-ing at 200°C and 80 bar entails very great difficulties as wellas __.
._ a long time.
In Mares et al. (Ind. Eng. Chem. Process Des. Dev. 1~(1) (1978), .
9-16), the conversion of ethyl 6-aminocaproate in ethanol into caprolactam is also investigated. It is found that quantitative cyclization is possible only at low temperatures and at high dilution. According to Mares et al., in particular a caprolactam yield of only 90 ~ is achievable from ethyl 6-aminocaproate at 200°C and in a reaction time of 10 hours. According to Mares et al., the yield can be increased to not more than 95 ~ at 150°C, but reaction times of 10 hours_or more are out of the question for commercial use.
Mares et al. likewise describe the conversion of ethyl 6-amino- -caproate in water into caprolactam at 200°C and in a reaction time of five hours with a yield of not more than 62.5 ~. In the same -publication, the conversion of 6-aminocaproamide into capro-lactam, both in water and in ethanol, is investigated, and yields of not more than 71 ~ in a reaction time of more than 70 minutes can be obtained.
Tetrahedron Lett. ~, (1980), 2443 describes the cyclization of -6-aminocaproic acid as a suspension in toluene in the presence of alumina or silica gel with removal of the water of reaction. For complete desorption of the caprolactam, the catalyst must be washed with methylene chloride/methanol and polymers must be BASF Aktiengesellschaft 930746 O.Z. 0050/44982 precipitated with diethyl ether. The yield of caprolactam is 82 ~
over alumina and 75 ~ over silica gel, but the reaction time is 20 hours in each case.
EP-A 271 815 describes the cyclization of 6-aminocaproates to _ _ give caprolactam, the esters being dissolved. in an aromatic hydrocarbon and then cyclized at from 100 to 320°C with simulta- __ neous removal of the alcohol formed.
Disadvantages are the separation of the alcohol under super-atmospheric pressure as well as the aromatic hydrocarbons, which are expensive to remove since they are high-boiling, and the long reaction times, for example 14 hours when the reaction is carried out in o-xylene (140°C).
EP-A 376 122 describes the cyclization of 6-aminocaproates in the presence of an aromatic hydrocarbon and water at from 230 to 350°C
to give caprolactam.
It is an object of the present invention to provide a process for the preparation of cyclic lactams by reacting an aminocarboxylic acid compound of the general formula I -H2N - (CH3)m - COR1 I
where R1 is -OH, -O-C1-CZZ-alkyl-or -NRaR3-and Rz and R3, indepen-dently of one another, are each hydrogen, C1-C1a-alkyl or CS-C$-cycloalkyl and m is an integer from 3 to 12, with water, which process does not have the disadvantages described above. _ We have found that this object is achieved by an improved process-for the preparation of cyclic lactams by reacting an amino-carboxylic acid compound of the general formula 1 H2N - (CH2)m - COR1 I
where RI is -OH, -0-C1-C12-alkyl or -NR~R3 and R2 and R3, indepen-dently of one another, are each hydrogen, C1-Ciz-alkyl or -CS-C8-cycloalkyl and m is an integer from 3 to 12, with water by carrying out the reaction in the liquid phase using a hetero-geneous catalyst.
The starting materials used in the novel process are amino-carboxylic acid compounds, preferably those of the general formula I
BASF Aktiengesellschaft 930746 O.Z. 0050/44982 HZN - (CH2)m - COR1 I
where R1 is -OH, -0-C1-Clz-alkyl or -NRZR3 and Rz and R3, indepen-dently of one another, are each hydrogen, C1-C12-alkyl or CS-Ca-cycloalkyl and m is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. -If the preferred starting compounds are those in which R1 is -OH
or -0-C1-C4-alkyl, such as -0-methyl, -0-ethyl, -O-n-propyl, -0-isopropyl, -0-n-butyl, -0-sec-butyl, -0-tert-butyl or -0-iso-.
butyl, -NR2R3 is -NHa, -NHMe, -NHEt, -NMe1 or -NEtz and m is 5. _ 6-Aminocaproic acid, methyl 6-aminocaproate, ethyl 6-amino-caproate, 6-amino-N-methylcaproamide, 6-amino-N,N-dimethylcapro- - _ amide, 6-amino-N-ethylcaproamide, 6-amino-N,N-diethylcaproamide and 6-aminocaproamide are very particularly preferred.
The starting compounds are commercially available or can be pre-pared, for example, according to EP 234,295 and Ind. Eng. Chem.
Pracess Des.Dev. ~ (1978), 9-16.
In the novel process, the aminocarboxylic acid compounds described above are reacted with water in the liquid phase using a heterogeneous catalyst to give cyclic lactams. Whenamino- _.._ ._ -_ carboxylic acid compounds of the general formula I are used, the __>
corresponding cyclic lactams of the general formula II
(CHI ) n I I
H-N - CO
where m has the abovementioned meanings, are obtained. Particu-larly preferred lactams are those in which m is 4, 5 or 6, in particular 5 (in the latter case, caprolactamis obtained). The __ reaction is carried out in the liquid phaseat in general from 140 to 320°C, preferably from 160 to 300°C; the pressure is usual-ly chosen to be from 0.5 to 25 MPa, but so that the reaction mix- ___ ture is liquid under the conditions used. The residence times are as a rule from 5 to 120, preferably from 10 to 60, minutes.
Advantageously, the aminocarboxylic acid compound is used in the form of a 1 - 50, preferably 5 - 50, particularly preferably 5 -25, ~ strength by weight solution in water or in a water/solvent mixture_ Examples of solvents aze alkanols, in particular C1-C4-alkanols, such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, isobutanol, sec-butanol and tert-butanol, BASF Aktienqesellschaft 930746 O.Z. 0050/44982 -polyols, such as diethylene glycol and tetraethylene glycol, lactams, such as pyrrolidone, caprolactam and alkyl-substituted lactams, in particular N-CI-C~-alkyllactams, such as N-methyl-pyrrolidone, N-methylcaprolactam or N-ethylcaprolactam. Ammonia, 5 too, may be present in the reaction. Mixtures of organic solvents may of course also be used.
Heterogeneous catalysts which may be used are, for example:
acidic, basic or amphoteric oxides of the elements of the second, third or fourth main group of the Periodic Table, such as boron oxide, alumina or silica as silica-gel, kieselguhr, quartz or mixtures thereof, and oxides of metals of the second to sixth subgroups of the Periodic Table, such as titanium dioxide as anatase or rutile, zirconium oxide or mixtures thereof. Oxides of -the lanthanides or actinides, such as lanthanum oxide, cerium oxide, thorium oxide, praseodymium oxide or neodymium oxide, or -mixtures thereof with abovementioned oxides may also be used.
Further catalysts may be, for example:
vanadium oxide, niobium oxide, iron oxide, chromium oxide, molyb-denum oxide, tungsten oxide and mixtures thereof_ Mixtures of these oxides with one another are also possible.
The abovementioned oxides may be doped with compounds of main groups I and VII of the Periodic Table or may contain these.
Zeolites, phosphates and heteropoly acids and acidic and alkaline ion exchangers, for example Naphion~', are also examples of suit-able catalysts.
If required, these catalysts may contain up to 50 ~ by weight in each case of copper, tin, zinc, manganese, iron, cobalt, nickel, ruthenium, palladium, platinum, silver or rhodium.
The amount of catalyst depends as a rule on the procedure: in a batchwise procedure, the amount of catalyst is chosen to be from 0.1 to 50, preferably from 1 to 30, ~ by weight, based on the aminocarboxylic acid compound of the general formula I;-in the continuous procedure, the catalyst space velocity is chosen to be from 0.1 to 5 kg per 1 per h, based on the aminocarboxylic acid compound of the general formula I.
In the novel process, cyclic lactams, in particular caprolactam, are obtained in high yield.
BASF Aktiengesellschaft -930746 O.Z. 0050/44982 Examples Example 1 5 A solution of 6-aminocaproic acid in water was passed, at 100 bar, into a heated tube reactor which had a capacity of 100 ml, diameter of 9 mm and a length of 400 mm and was filled with titanium dioxide (anatase) in the form of 1.5 mm extrudates.
The product stream leaving the reactor was analyzed by gas 10 chromatography and high-pressure liquid chromatography (HPLC).
AminocarboxylicWater Temperature Residence Yield acid [$] [~C] time [min]
Example 2 Similarly to the experiments described in Example 1, a solution of aminocaproic acid in ethanol/water was pumped through a tube reactor filled with titanium oxide extrudates.
AminocarboxylicWater Ethanol Temperature Residence Yield acid [~] [~] (~C] time [~]
[min]
Example 3 Similarly to the experiments described in Example 1, a solution of ethyl aminocaproate in ethanol, in the presence of water, was pumped through a tube reactor filled with titanium oxide extru-dates.
Ethyl Water EthanolTemper- Residence Conver- Selec- Yield amino- [~] f~] ature time sion tivity caproate [~C] [min]
[~l 10 1.1 88.9 220 15 97 93 90 10 1.1 88.9 220 30 97 85 83 10 1.1 88.9 220 60 100 79 79 10 4.4 85.6 220 30 97 95 92 BASF Aktiengesellschaft 930746 O.Z. 0050/44982 ~~~~89 ~ 7 Comparative example In each case a 10 ~ strength by weight solution of 6-aminocaproic acid in ethanol was heated to 200°C during different residence times, according to Ind. Eng. Chem. Process Des. Dev. ,y2 (1978), 16. The results are listed in the table below.
Residence Temperature Conversion Selectivity Yield of time [~C] [~] ['k] caprolactam [min] _ 200' 90 90 81 Yields above ~
were not obtained.
Preparation of cyclic lactams The present invention relates to a process for the preparation of cyclic lactams by reacting an aminocarboxylic acid compound of the general formula I
HaN - (CH2)m - COR1 I
where R1 is -OH, -0-C1-Clz-alkyl or -NRZR3 and Ra and R3, indepen-dently of one another, are each hydrogen, Cl-Ci2-alkyl or r C5-Cg-cycloalkyl and m is an integer from 3 to 12, with water.
US 3,485,821 relates to the uncatalyzed conversion of amino-caproic acid, aminocaproamide and alkyl-substituted derivatives thereof into caprolactam or alkyl-substituted caprolactam by carrying out the reaction in water at from 150 to 350°C, it being .
possible to add ammonium salts to the water. However, the convey- _., sions to caprolactam are not higher than 90 DE-A 2,535,689 describes a process for the preparation of capro lactam by converting 6-aminocaproic acid dissolved in methanol or ethanol, the solvent having an alcohol content of at least60 ~-by volume and the reaction being carried out at from 170 to 200°C.
According to DE-A 2,535,689, higher temperatures, in particular 220°C or higher, lead to the increased formation of the comes-ponding alkyl ester of 6-aminocaproic acid, which finally results in increased oliqomer formation. According to this document, water contents above 40 ~ by volume should lead to the formation. -of open-chain polyamides. For commercial use, the addition of the 6-aminocaproic acid is a considerable disadvantage since the aminocaproic acid should be completely dissolved before it is converted into caprolactam, and hence 6-aminocaproic acid must be constantly added-and its consumption monitored.
Ind. Eng. Chem. Process Des. Dev. ~(1) (1978), 9-16 (Mares et al.) describes the conversion of 6-.aminocaproic acid, both in water and in ethanol, into caprolactam without the addition of a catalyst. The yield of caprolactam in water at a reaction temperature of 211°C is only 65 ~, while yields of up to 98 ~ are _ said to be achievable in pure ethanol- Eiowever, the yields of 92 ~ or higher described by Mares et al. could not be_ repeated in our own experiments. Rather, these high yields can be explained-only by the fact that Mares et al. did not use a 10 ~ strength by °. BASF Aktiengesellschaft 930746 O.Z. 0050/44982 weight solution of 6-aminocaproic acid but cyclized minimum -6-aminocaproic acid concentrations to give caprolactam by contin-uous addition of 6-aminocaproic acid to the ethanolic solution. -Since caprolactam is-stable under the chosen reaction conditions, it was possible to obtain the high yields (92 ~ and 98 ~) only by virtue.of the fact that the concentration of caprolactam in-creased during the reaction. This assumption is supported by US 2,535,689 (with Mares as coinventor). Example 1 of this U.S.
patent indicates that a reaction of the 6-aminocaproic acid is to be prevented before the 6-aminocaproic acid has completely dis- -_ solved. For this purpose, the 6-aminocaproic acid should be added- -so slowly that no solid acid is present in the solvent but the 6-aminocaproic acid is dispersed virtually immediately in the hot solvent and is completely dissolved or is dispersed during heat-ing. Since the maximum solubility of 6-aminocaproic acid in both cold and boiling ethanol (78°C) is only 1.3 g/I (= 0.13 ~ by weight), it is clear that, in Mares et al.., 6-aminocaproic acid could be added only gradually in order to obtain a solution which, purely theoretically, contained 10 ~ by weight of 6-amino-caproic acid. Otherwise, the technicalprocedure for such meter-ing at 200°C and 80 bar entails very great difficulties as wellas __.
._ a long time.
In Mares et al. (Ind. Eng. Chem. Process Des. Dev. 1~(1) (1978), .
9-16), the conversion of ethyl 6-aminocaproate in ethanol into caprolactam is also investigated. It is found that quantitative cyclization is possible only at low temperatures and at high dilution. According to Mares et al., in particular a caprolactam yield of only 90 ~ is achievable from ethyl 6-aminocaproate at 200°C and in a reaction time of 10 hours. According to Mares et al., the yield can be increased to not more than 95 ~ at 150°C, but reaction times of 10 hours_or more are out of the question for commercial use.
Mares et al. likewise describe the conversion of ethyl 6-amino- -caproate in water into caprolactam at 200°C and in a reaction time of five hours with a yield of not more than 62.5 ~. In the same -publication, the conversion of 6-aminocaproamide into capro-lactam, both in water and in ethanol, is investigated, and yields of not more than 71 ~ in a reaction time of more than 70 minutes can be obtained.
Tetrahedron Lett. ~, (1980), 2443 describes the cyclization of -6-aminocaproic acid as a suspension in toluene in the presence of alumina or silica gel with removal of the water of reaction. For complete desorption of the caprolactam, the catalyst must be washed with methylene chloride/methanol and polymers must be BASF Aktiengesellschaft 930746 O.Z. 0050/44982 precipitated with diethyl ether. The yield of caprolactam is 82 ~
over alumina and 75 ~ over silica gel, but the reaction time is 20 hours in each case.
EP-A 271 815 describes the cyclization of 6-aminocaproates to _ _ give caprolactam, the esters being dissolved. in an aromatic hydrocarbon and then cyclized at from 100 to 320°C with simulta- __ neous removal of the alcohol formed.
Disadvantages are the separation of the alcohol under super-atmospheric pressure as well as the aromatic hydrocarbons, which are expensive to remove since they are high-boiling, and the long reaction times, for example 14 hours when the reaction is carried out in o-xylene (140°C).
EP-A 376 122 describes the cyclization of 6-aminocaproates in the presence of an aromatic hydrocarbon and water at from 230 to 350°C
to give caprolactam.
It is an object of the present invention to provide a process for the preparation of cyclic lactams by reacting an aminocarboxylic acid compound of the general formula I -H2N - (CH3)m - COR1 I
where R1 is -OH, -O-C1-CZZ-alkyl-or -NRaR3-and Rz and R3, indepen-dently of one another, are each hydrogen, C1-C1a-alkyl or CS-C$-cycloalkyl and m is an integer from 3 to 12, with water, which process does not have the disadvantages described above. _ We have found that this object is achieved by an improved process-for the preparation of cyclic lactams by reacting an amino-carboxylic acid compound of the general formula 1 H2N - (CH2)m - COR1 I
where RI is -OH, -0-C1-C12-alkyl or -NR~R3 and R2 and R3, indepen-dently of one another, are each hydrogen, C1-Ciz-alkyl or -CS-C8-cycloalkyl and m is an integer from 3 to 12, with water by carrying out the reaction in the liquid phase using a hetero-geneous catalyst.
The starting materials used in the novel process are amino-carboxylic acid compounds, preferably those of the general formula I
BASF Aktiengesellschaft 930746 O.Z. 0050/44982 HZN - (CH2)m - COR1 I
where R1 is -OH, -0-C1-Clz-alkyl or -NRZR3 and Rz and R3, indepen-dently of one another, are each hydrogen, C1-C12-alkyl or CS-Ca-cycloalkyl and m is 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. -If the preferred starting compounds are those in which R1 is -OH
or -0-C1-C4-alkyl, such as -0-methyl, -0-ethyl, -O-n-propyl, -0-isopropyl, -0-n-butyl, -0-sec-butyl, -0-tert-butyl or -0-iso-.
butyl, -NR2R3 is -NHa, -NHMe, -NHEt, -NMe1 or -NEtz and m is 5. _ 6-Aminocaproic acid, methyl 6-aminocaproate, ethyl 6-amino-caproate, 6-amino-N-methylcaproamide, 6-amino-N,N-dimethylcapro- - _ amide, 6-amino-N-ethylcaproamide, 6-amino-N,N-diethylcaproamide and 6-aminocaproamide are very particularly preferred.
The starting compounds are commercially available or can be pre-pared, for example, according to EP 234,295 and Ind. Eng. Chem.
Pracess Des.Dev. ~ (1978), 9-16.
In the novel process, the aminocarboxylic acid compounds described above are reacted with water in the liquid phase using a heterogeneous catalyst to give cyclic lactams. Whenamino- _.._ ._ -_ carboxylic acid compounds of the general formula I are used, the __>
corresponding cyclic lactams of the general formula II
(CHI ) n I I
H-N - CO
where m has the abovementioned meanings, are obtained. Particu-larly preferred lactams are those in which m is 4, 5 or 6, in particular 5 (in the latter case, caprolactamis obtained). The __ reaction is carried out in the liquid phaseat in general from 140 to 320°C, preferably from 160 to 300°C; the pressure is usual-ly chosen to be from 0.5 to 25 MPa, but so that the reaction mix- ___ ture is liquid under the conditions used. The residence times are as a rule from 5 to 120, preferably from 10 to 60, minutes.
Advantageously, the aminocarboxylic acid compound is used in the form of a 1 - 50, preferably 5 - 50, particularly preferably 5 -25, ~ strength by weight solution in water or in a water/solvent mixture_ Examples of solvents aze alkanols, in particular C1-C4-alkanols, such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, isobutanol, sec-butanol and tert-butanol, BASF Aktienqesellschaft 930746 O.Z. 0050/44982 -polyols, such as diethylene glycol and tetraethylene glycol, lactams, such as pyrrolidone, caprolactam and alkyl-substituted lactams, in particular N-CI-C~-alkyllactams, such as N-methyl-pyrrolidone, N-methylcaprolactam or N-ethylcaprolactam. Ammonia, 5 too, may be present in the reaction. Mixtures of organic solvents may of course also be used.
Heterogeneous catalysts which may be used are, for example:
acidic, basic or amphoteric oxides of the elements of the second, third or fourth main group of the Periodic Table, such as boron oxide, alumina or silica as silica-gel, kieselguhr, quartz or mixtures thereof, and oxides of metals of the second to sixth subgroups of the Periodic Table, such as titanium dioxide as anatase or rutile, zirconium oxide or mixtures thereof. Oxides of -the lanthanides or actinides, such as lanthanum oxide, cerium oxide, thorium oxide, praseodymium oxide or neodymium oxide, or -mixtures thereof with abovementioned oxides may also be used.
Further catalysts may be, for example:
vanadium oxide, niobium oxide, iron oxide, chromium oxide, molyb-denum oxide, tungsten oxide and mixtures thereof_ Mixtures of these oxides with one another are also possible.
The abovementioned oxides may be doped with compounds of main groups I and VII of the Periodic Table or may contain these.
Zeolites, phosphates and heteropoly acids and acidic and alkaline ion exchangers, for example Naphion~', are also examples of suit-able catalysts.
If required, these catalysts may contain up to 50 ~ by weight in each case of copper, tin, zinc, manganese, iron, cobalt, nickel, ruthenium, palladium, platinum, silver or rhodium.
The amount of catalyst depends as a rule on the procedure: in a batchwise procedure, the amount of catalyst is chosen to be from 0.1 to 50, preferably from 1 to 30, ~ by weight, based on the aminocarboxylic acid compound of the general formula I;-in the continuous procedure, the catalyst space velocity is chosen to be from 0.1 to 5 kg per 1 per h, based on the aminocarboxylic acid compound of the general formula I.
In the novel process, cyclic lactams, in particular caprolactam, are obtained in high yield.
BASF Aktiengesellschaft -930746 O.Z. 0050/44982 Examples Example 1 5 A solution of 6-aminocaproic acid in water was passed, at 100 bar, into a heated tube reactor which had a capacity of 100 ml, diameter of 9 mm and a length of 400 mm and was filled with titanium dioxide (anatase) in the form of 1.5 mm extrudates.
The product stream leaving the reactor was analyzed by gas 10 chromatography and high-pressure liquid chromatography (HPLC).
AminocarboxylicWater Temperature Residence Yield acid [$] [~C] time [min]
Example 2 Similarly to the experiments described in Example 1, a solution of aminocaproic acid in ethanol/water was pumped through a tube reactor filled with titanium oxide extrudates.
AminocarboxylicWater Ethanol Temperature Residence Yield acid [~] [~] (~C] time [~]
[min]
Example 3 Similarly to the experiments described in Example 1, a solution of ethyl aminocaproate in ethanol, in the presence of water, was pumped through a tube reactor filled with titanium oxide extru-dates.
Ethyl Water EthanolTemper- Residence Conver- Selec- Yield amino- [~] f~] ature time sion tivity caproate [~C] [min]
[~l 10 1.1 88.9 220 15 97 93 90 10 1.1 88.9 220 30 97 85 83 10 1.1 88.9 220 60 100 79 79 10 4.4 85.6 220 30 97 95 92 BASF Aktiengesellschaft 930746 O.Z. 0050/44982 ~~~~89 ~ 7 Comparative example In each case a 10 ~ strength by weight solution of 6-aminocaproic acid in ethanol was heated to 200°C during different residence times, according to Ind. Eng. Chem. Process Des. Dev. ,y2 (1978), 16. The results are listed in the table below.
Residence Temperature Conversion Selectivity Yield of time [~C] [~] ['k] caprolactam [min] _ 200' 90 90 81 Yields above ~
were not obtained.
Claims (4)
1. A process for the preparation of a cyclic-lactam by reacting an aminocarboxylic acid compound of the formula I
H2N - (CH2)m - COR1 where R1 is -OH, -O-C1-C12-alkyl or -NR2R3 and R2 and R3, independently of one another, are each hydrogen, C1-C12-alkyl or C5-C8-cycloalkyl and m is an integer from 3 to 12, with water, wherein the reaction is carried out in the liquid phase using a heterogeneous catalyst.
H2N - (CH2)m - COR1 where R1 is -OH, -O-C1-C12-alkyl or -NR2R3 and R2 and R3, independently of one another, are each hydrogen, C1-C12-alkyl or C5-C8-cycloalkyl and m is an integer from 3 to 12, with water, wherein the reaction is carried out in the liquid phase using a heterogeneous catalyst.
2. A process as claimed in claim 1, wherein the reaction is carried out at from 140 to 320°C.
3. A process as claimed in claim 1 or 2, wherein the amino-carboxylic acid compound used is a compound selected from the group consisting of 6-aminocaproic acid, methyl 6-amino-caproate, ethyl 6-aminocaproate, 6-amino-N-methylcaproamide, 6-amino-N,N-dimethylcaproamide, 6-amino-N-ethylcaproamide, 6-amino-N,N-diethylcaproamide and 6-aminocaproamide.
4. A process as claimed in any of claims 1 to 3, wherein the reaction is carried out in water or in a mixture of water and an organic solvent.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4422610.1 | 1994-06-28 | ||
| DE4422610A DE4422610A1 (en) | 1994-06-28 | 1994-06-28 | Process for the preparation of cyclic lactams |
| PCT/EP1995/002338 WO1996000722A1 (en) | 1994-06-28 | 1995-06-16 | Process for producing cyclic lactames |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2194189A1 CA2194189A1 (en) | 1996-01-11 |
| CA2194189C true CA2194189C (en) | 2005-11-29 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002194189A Expired - Fee Related CA2194189C (en) | 1994-06-28 | 1995-06-16 | Process for producing cyclic lactames |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2194189C (en) |
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1995
- 1995-06-16 CA CA002194189A patent/CA2194189C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2194189A1 (en) | 1996-01-11 |
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