CA2218132A1 - The preparation of caprolactam - Google Patents
The preparation of caprolactam Download PDFInfo
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- CA2218132A1 CA2218132A1 CA002218132A CA2218132A CA2218132A1 CA 2218132 A1 CA2218132 A1 CA 2218132A1 CA 002218132 A CA002218132 A CA 002218132A CA 2218132 A CA2218132 A CA 2218132A CA 2218132 A1 CA2218132 A1 CA 2218132A1
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- Prior art keywords
- titanium dioxide
- water
- weight
- range
- amino
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
- C07D201/08—Preparation of lactams from carboxylic acids or derivatives thereof, e.g. hydroxy carboxylic acids, lactones or nitriles
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Catalysts (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Other In-Based Heterocyclic Compounds (AREA)
- Polyamides (AREA)
- Hydrogenated Pyridines (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Production of cyclic lactams by the reaction of amino carboxylic acid nitriles with water, performed in the liquid phase in the presence of heterogeneous catalysts based on titanium dioxide with a rutile content in the range from 0.1 to 95 wt.% and an anatase content in the range from 99.9 to 5 wt.% in relation to the total titanium dioxide content.
Description
BASF Aktiengesellschaft 950397 O.Z. 0050/45885 .
The preparation of caprolactam The present invention relates to a novel process for preparing 5 cyclic lactams by reacting amino carbonitriles with water in the presence of catalysts.
US-A 4 628 085 discloses the reaction of 6-aminocapronitrile with water in the gas phase on acidic silica gel at 300~C. The reaction 10 takes place quantitatively with an initial selectivity of 95 % to produce caprolactam, but a rapid decline in productivity and se-lectivity is to be found. A similar process is described in US-A 4 625 023, in which a highly diluted gas stream comprising 6-aminocapronitrile, adiponitrile, ammonia, water and carrier gas 15 is passed over a silica gel and a copper/chromium/barium-titanium oxide catalyst bed. Caprolactam is obtained with a selectivity of 91 %, with 85 % conversion. Once again there is observed to be a rapid deactivation of the catalyst.
20 US-A 2 301 964 relates to the uncatalyzed conversion of 6-amino-capronitrile into caprolactam in aqueous solution at 285 C. The yields are below 80 %.
FR-A 2 029 540 describes a process for the cyclization of 6-ami-25 nocapronitrile to caprolactam using homogeneous metal catalysts from the zinc and copper group in aqueous solution, resulting in caprolactam in yields of up to 83 %. However, complete removal of the catalyst from the required product caprolactam is problematic because the latter forms complexes with the metals used.
It is an object of the present invention to provide a process for preparing cyclic lactams by reacting amino carbonitriles with water which does not involve the disadvantages described above.
35 We have found that this object is achieved by carrying out the reaction in liquid phase in the presence of heterogeneous cata-lysts based on titanium dioxide with a rutile content in the range from 0.1 to 95 % by weight and an anatase content of from 99.9 to 5 % by weight, in each case based on the total content of 40 titanium dioxide.
Preferred embodiments of the process according to the invention are evident from the dependent claims.
BASF Aktiengesellschaft 950397 O.Z. 0050/45885 The starting materials employed in the process according to the invention are amino carbonitriles, preferably those of the gen-eral formula I
S _ _ _ _ ~1 H2N c cH2 ce N (I) - n - - m where n and m can each have the values 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, and the total of n + m is at least 3, preferably at 15 least 4.
Rl and R2 can in principle be substituents of any type, it merely being necessary to ensure that the required cyclization reaction is unaffected by the substituents. R1 and R2 are preferably, inde-20 pendently of one another, C1-C6-alkyl or Cs-C7-cycloalkyl groups or C6-C12-aryl groups.
Particularly preferred starting compounds are amino carbonitriles of the general formula H2N--(CH2)m~--C~ N
where m has a value of 3, 4, 5 or 6, in particular 5. Where m 2 5, the starting compound is 6-aminocapronitrile.
In the process according to the invention, the amino carboni-triles described above are reacted with water in liquid phase us-ing heterogeneous catalysts to give cyclic lactams. Use of amino carbonitriles of the formula I results in the corresponding cy-35 clic lactams of the formula II
(II) ~C= O
N
H
BASF Aktiengesellschaft 950397 O.Z. UU~U/ 4~5 where n, m, R1 and R2 have the abovementioned meanings. Particu-larly preferred lactams are those where n is 0 and m has a value of 4, 5 or 6, in particular 5 (in the latter case, caprolactam is obtained).
The reaction is carried out in liquid phase at temperatures of, in general, 140 to 320 C, preferably 160 to 280 C; the pressure is generally in the range from 1 to 250 bar, preferably from 5 to 150 bar, it being necessary to take care that the reaction mix-10 ture is mainly, ie. without the catalyst which is pre~ent insolid phase, liquid under the conditions used. The holdup times are generally in the range from 1 to 120, preferably 1 to 90 and, in particular, 1 to 60, min. In some cases, holdup times of from l to 10 min have proven entirely adequate.
In general, at least 0.01 mol, preferably 0.1-20 and, in particu-lar, 1-5, mol of water are employed per mol of amino carboni-trile.
20 The amino carbonitrile is advantageously employed in the form of a 1-50 % by weight, in particular 5-50 % by weight, particularly preferably 5-30 % by weight, solution in water (in which case the solvent is also a reactant) or in water/solvent mixtures. Exam-ples of solvents which may be mentioned are alkanols such as 25 methanol, ethanol, n- and i-propanol, n-, i- and t-butanol and polyols such as diethylene glycol and tetraethylene glycol, hy-drocarbons such as petroleum ether, benzene, toluene, xylene, lactams such as pyrrolidone or caprolactam or alkyl-substituted lactams such as N-methylpyrrolidone, N-methylcaprolactam or 30 N-ethylcaprolactam, and carboxylic esters, preferably of carbox-ylic acids with from 1 to 8 carbon atoms. Ammonia may also be present in the reaction. It is, of course, al~o possible to use mixtures of organic solvents. Mixtures of water and alkanols in the water/alkanol ratio by weight of 1-75 to 25-99, preferably 35 1-50 to 50-99, have emerged as particularly advantageous in some cases.
The process according to the invention is generally carried out in the presence of titanium dioxide catalysts which have a rutile 40 content in the range from 0.1 to 95, preferably from 1 to 90, %
by weight and an anatase content in the range from 99.9 to 5, preferably from 99 to 10, % by weight, in each case based on the total content of titanium dioxide.
BASF Aktiengesellschaft 950397 O.Z. 0050/45~5 In a preferred embodiment, the reaction is carried out in a fixed bed using the catalysts in the form of extrudates or tablets, with the tablets and extrudates preferably having a diameter of from 1 to 10 mm.
The extrudates and tablets can be produced by conventional meth-ods using titanium dioxide powder which already has the required content of anatase and rutile, or which is obtained by pyrrolysis starting either from a pure anatase modification or a mixed form 10 contAini~g anatase and rutile phases or a mixture of pure anatase and rutile modifications, pyrolyzing with an appropriate tempera-ture and holdup time (both are known to the skilled worker, for example from Catalysis Today 14 (1992) 225-242~ until the re-quired anatase to rutile ratio is reached.
Corresponding powders are commercially obtAi~Ahle~ for example the titanium dioxide powders P25~ (20-30 % by weight rutile and 80-70 % by weight anatase) from Degussa and S150~ and S140~ (each 100 % by weight anatase) from Finti-Kemira.
The titanium dioxide can be used as such or as supported cata-lyst, in which case it can be applied to a mechanically and chem-ically stable support, usually with a high surface area.
25 The titanium dioxide can have been prepared by precipitation from aqueous solutions, eg. by the sulfate process or by other pro-cesses such as pyrogenic preparation of fine titanium dioxide powders which can be bought.
30 If required, the rutile/anatase-contAining titanium dioxide can be mixed with other oxides such as aluminum oxide, zirconium ox-ide or cerium oxide. Several methods are available for preparing mixtures of various oxides. The oxides or their precursor com-pounds which can be converted into the oxides by calcination can 35 be prepared, for example, by precipitation together from solu-tion. This generally results in a very good dispersion of the two oxides used. Precipitation of the oxide or precursor mixtures can also take place by precipitating one oxide or precursor in the presence of the second oxide or precursor which is in the form of 40 a suspension of finely dispersed particles. Another method com-prises ?chAnically mixing the oxide or precursor powders, in which case this mixture can be used as starting material for pro-ducing extrudates or tablets.
45 Various methods are available for producing supported catalysts.
Thus, the titanium dioxide can be applied in the form of a sol to the support by simple impregnation. Drying and calcination BASF Aktiengesellschaft 950397 O.Z. 0050/45885 normally remove the volatile constituents of the sol from the catalyst. Sols of this type for titanium dioxide can be bought.
Another possibility for applying layers of the active titanium 5 dioxide comprises hydroly~is or pyrolysis of organic or inorganic compounds. Thus, a ceramic support can be coated with titanium dioxide in a thin layer by hydrolyzing titanium isopropylate or other Ti alkoxides. Another suitable compound is TiCl4. Suitable supports are powders, extrudates or tablets of titanium dioxide 10 itself or other stable oxides such as silicon dioxide. The sup-ports used can be designed to be macroporous to improve material transport. It is important to take care during the pyrolysis of the titanium dioxide that both rutile and anatase phases result in the abovementioned ranges.
The process according to the invention results in cyclic lactams, in particular caprolactam, in high yield with good selectivities and constancy of catalytic activity.
20 Examples Examples l to 7 A solution of 6-aminocapronitrile (ACN) in water and ethanol in 25 the ratios by weight stated in the table was passed under 100 bar in a heated tubular reactor of capacity 25 ml ~diameter 6 mm;
length 800 mm) packed with titanium dioxide in the form of tab-lets or extrudates. The product stream leaving the reactor was analyzed by gas chromatography. The results are likewise to be 30 found in the table.
.BASF-Aktiengesellschaft 950397 O.Z. 0050/45885 ,.
'~ ~ O oa~
o o --I ~n co o a ~
N --I ~ ~ ~ ~ O E~
~1 ~0 .
dP ~ a~ co ~ ~ ~
a ~ ~ ~
o o o a O
l _ ~ .~ ~q W
o a,~ ~ 3 a O ~ O ~ ~ 0 ~ ~ c t" ~ o o o ~ O
O N ~ .I r~
U ~ ~ ,~ ~ U
S ,C .~
0 0 0 0 0 a~ 0 ~~ 1 ~ H
~ a o ~ ~ 3 ~
b ~ P ~
x ~ 0 ~ x ~ 0 ~ x ~ x ~ x ~ ~ a a a a ~
~ tn ~ -- o ~ ~
C, ~ ~ ~ y, , p ~ ~ ~U ~ 0 E~
~ ~ ~ ~ ~ ~ E~ ~~ J o ~~
p, O :~ a u~ ~ m x ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ m
The preparation of caprolactam The present invention relates to a novel process for preparing 5 cyclic lactams by reacting amino carbonitriles with water in the presence of catalysts.
US-A 4 628 085 discloses the reaction of 6-aminocapronitrile with water in the gas phase on acidic silica gel at 300~C. The reaction 10 takes place quantitatively with an initial selectivity of 95 % to produce caprolactam, but a rapid decline in productivity and se-lectivity is to be found. A similar process is described in US-A 4 625 023, in which a highly diluted gas stream comprising 6-aminocapronitrile, adiponitrile, ammonia, water and carrier gas 15 is passed over a silica gel and a copper/chromium/barium-titanium oxide catalyst bed. Caprolactam is obtained with a selectivity of 91 %, with 85 % conversion. Once again there is observed to be a rapid deactivation of the catalyst.
20 US-A 2 301 964 relates to the uncatalyzed conversion of 6-amino-capronitrile into caprolactam in aqueous solution at 285 C. The yields are below 80 %.
FR-A 2 029 540 describes a process for the cyclization of 6-ami-25 nocapronitrile to caprolactam using homogeneous metal catalysts from the zinc and copper group in aqueous solution, resulting in caprolactam in yields of up to 83 %. However, complete removal of the catalyst from the required product caprolactam is problematic because the latter forms complexes with the metals used.
It is an object of the present invention to provide a process for preparing cyclic lactams by reacting amino carbonitriles with water which does not involve the disadvantages described above.
35 We have found that this object is achieved by carrying out the reaction in liquid phase in the presence of heterogeneous cata-lysts based on titanium dioxide with a rutile content in the range from 0.1 to 95 % by weight and an anatase content of from 99.9 to 5 % by weight, in each case based on the total content of 40 titanium dioxide.
Preferred embodiments of the process according to the invention are evident from the dependent claims.
BASF Aktiengesellschaft 950397 O.Z. 0050/45885 The starting materials employed in the process according to the invention are amino carbonitriles, preferably those of the gen-eral formula I
S _ _ _ _ ~1 H2N c cH2 ce N (I) - n - - m where n and m can each have the values 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9, and the total of n + m is at least 3, preferably at 15 least 4.
Rl and R2 can in principle be substituents of any type, it merely being necessary to ensure that the required cyclization reaction is unaffected by the substituents. R1 and R2 are preferably, inde-20 pendently of one another, C1-C6-alkyl or Cs-C7-cycloalkyl groups or C6-C12-aryl groups.
Particularly preferred starting compounds are amino carbonitriles of the general formula H2N--(CH2)m~--C~ N
where m has a value of 3, 4, 5 or 6, in particular 5. Where m 2 5, the starting compound is 6-aminocapronitrile.
In the process according to the invention, the amino carboni-triles described above are reacted with water in liquid phase us-ing heterogeneous catalysts to give cyclic lactams. Use of amino carbonitriles of the formula I results in the corresponding cy-35 clic lactams of the formula II
(II) ~C= O
N
H
BASF Aktiengesellschaft 950397 O.Z. UU~U/ 4~5 where n, m, R1 and R2 have the abovementioned meanings. Particu-larly preferred lactams are those where n is 0 and m has a value of 4, 5 or 6, in particular 5 (in the latter case, caprolactam is obtained).
The reaction is carried out in liquid phase at temperatures of, in general, 140 to 320 C, preferably 160 to 280 C; the pressure is generally in the range from 1 to 250 bar, preferably from 5 to 150 bar, it being necessary to take care that the reaction mix-10 ture is mainly, ie. without the catalyst which is pre~ent insolid phase, liquid under the conditions used. The holdup times are generally in the range from 1 to 120, preferably 1 to 90 and, in particular, 1 to 60, min. In some cases, holdup times of from l to 10 min have proven entirely adequate.
In general, at least 0.01 mol, preferably 0.1-20 and, in particu-lar, 1-5, mol of water are employed per mol of amino carboni-trile.
20 The amino carbonitrile is advantageously employed in the form of a 1-50 % by weight, in particular 5-50 % by weight, particularly preferably 5-30 % by weight, solution in water (in which case the solvent is also a reactant) or in water/solvent mixtures. Exam-ples of solvents which may be mentioned are alkanols such as 25 methanol, ethanol, n- and i-propanol, n-, i- and t-butanol and polyols such as diethylene glycol and tetraethylene glycol, hy-drocarbons such as petroleum ether, benzene, toluene, xylene, lactams such as pyrrolidone or caprolactam or alkyl-substituted lactams such as N-methylpyrrolidone, N-methylcaprolactam or 30 N-ethylcaprolactam, and carboxylic esters, preferably of carbox-ylic acids with from 1 to 8 carbon atoms. Ammonia may also be present in the reaction. It is, of course, al~o possible to use mixtures of organic solvents. Mixtures of water and alkanols in the water/alkanol ratio by weight of 1-75 to 25-99, preferably 35 1-50 to 50-99, have emerged as particularly advantageous in some cases.
The process according to the invention is generally carried out in the presence of titanium dioxide catalysts which have a rutile 40 content in the range from 0.1 to 95, preferably from 1 to 90, %
by weight and an anatase content in the range from 99.9 to 5, preferably from 99 to 10, % by weight, in each case based on the total content of titanium dioxide.
BASF Aktiengesellschaft 950397 O.Z. 0050/45~5 In a preferred embodiment, the reaction is carried out in a fixed bed using the catalysts in the form of extrudates or tablets, with the tablets and extrudates preferably having a diameter of from 1 to 10 mm.
The extrudates and tablets can be produced by conventional meth-ods using titanium dioxide powder which already has the required content of anatase and rutile, or which is obtained by pyrrolysis starting either from a pure anatase modification or a mixed form 10 contAini~g anatase and rutile phases or a mixture of pure anatase and rutile modifications, pyrolyzing with an appropriate tempera-ture and holdup time (both are known to the skilled worker, for example from Catalysis Today 14 (1992) 225-242~ until the re-quired anatase to rutile ratio is reached.
Corresponding powders are commercially obtAi~Ahle~ for example the titanium dioxide powders P25~ (20-30 % by weight rutile and 80-70 % by weight anatase) from Degussa and S150~ and S140~ (each 100 % by weight anatase) from Finti-Kemira.
The titanium dioxide can be used as such or as supported cata-lyst, in which case it can be applied to a mechanically and chem-ically stable support, usually with a high surface area.
25 The titanium dioxide can have been prepared by precipitation from aqueous solutions, eg. by the sulfate process or by other pro-cesses such as pyrogenic preparation of fine titanium dioxide powders which can be bought.
30 If required, the rutile/anatase-contAining titanium dioxide can be mixed with other oxides such as aluminum oxide, zirconium ox-ide or cerium oxide. Several methods are available for preparing mixtures of various oxides. The oxides or their precursor com-pounds which can be converted into the oxides by calcination can 35 be prepared, for example, by precipitation together from solu-tion. This generally results in a very good dispersion of the two oxides used. Precipitation of the oxide or precursor mixtures can also take place by precipitating one oxide or precursor in the presence of the second oxide or precursor which is in the form of 40 a suspension of finely dispersed particles. Another method com-prises ?chAnically mixing the oxide or precursor powders, in which case this mixture can be used as starting material for pro-ducing extrudates or tablets.
45 Various methods are available for producing supported catalysts.
Thus, the titanium dioxide can be applied in the form of a sol to the support by simple impregnation. Drying and calcination BASF Aktiengesellschaft 950397 O.Z. 0050/45885 normally remove the volatile constituents of the sol from the catalyst. Sols of this type for titanium dioxide can be bought.
Another possibility for applying layers of the active titanium 5 dioxide comprises hydroly~is or pyrolysis of organic or inorganic compounds. Thus, a ceramic support can be coated with titanium dioxide in a thin layer by hydrolyzing titanium isopropylate or other Ti alkoxides. Another suitable compound is TiCl4. Suitable supports are powders, extrudates or tablets of titanium dioxide 10 itself or other stable oxides such as silicon dioxide. The sup-ports used can be designed to be macroporous to improve material transport. It is important to take care during the pyrolysis of the titanium dioxide that both rutile and anatase phases result in the abovementioned ranges.
The process according to the invention results in cyclic lactams, in particular caprolactam, in high yield with good selectivities and constancy of catalytic activity.
20 Examples Examples l to 7 A solution of 6-aminocapronitrile (ACN) in water and ethanol in 25 the ratios by weight stated in the table was passed under 100 bar in a heated tubular reactor of capacity 25 ml ~diameter 6 mm;
length 800 mm) packed with titanium dioxide in the form of tab-lets or extrudates. The product stream leaving the reactor was analyzed by gas chromatography. The results are likewise to be 30 found in the table.
.BASF-Aktiengesellschaft 950397 O.Z. 0050/45885 ,.
'~ ~ O oa~
o o --I ~n co o a ~
N --I ~ ~ ~ ~ O E~
~1 ~0 .
dP ~ a~ co ~ ~ ~
a ~ ~ ~
o o o a O
l _ ~ .~ ~q W
o a,~ ~ 3 a O ~ O ~ ~ 0 ~ ~ c t" ~ o o o ~ O
O N ~ .I r~
U ~ ~ ,~ ~ U
S ,C .~
0 0 0 0 0 a~ 0 ~~ 1 ~ H
~ a o ~ ~ 3 ~
b ~ P ~
x ~ 0 ~ x ~ 0 ~ x ~ x ~ x ~ ~ a a a a ~
~ tn ~ -- o ~ ~
C, ~ ~ ~ y, , p ~ ~ ~U ~ 0 E~
~ ~ ~ ~ ~ ~ E~ ~~ J o ~~
p, O :~ a u~ ~ m x ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ m
Claims (5)
1. A process for preparing cyclic lactams by reacting amino carbonitriles with water in the presence of catalysts, wherein the reaction is carried out in liquid phase in the presence of heterogeneous catalysts based on titanium dioxide with a rutile content in the range from 0.1 to 95 % by weight and an anatase content in the range from 99.9 to 5 % by weight, in each case based on the total content of titanium dioxide.
2. A process as claimed in claim 1, wherein the reaction is carried out at a temperature in the range from 140 to 320° C.
3. A process as claimed in either of claims 1 and 2, wherein amino carbonitriles of the formula H2N~(CH2)m~C~N
where m is 3, 4, 5 or 6, are employed.
where m is 3, 4, 5 or 6, are employed.
4. A process as claimed in claim 3, wherein 6-aminocapronitrile is employed as amino carbonitrile.
5. A process as claimed in any of claims 1 to 4, wherein a 1-50 % by weight solution of the amino carbonitrile in water or in water/org. solvent mixtures is employed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19517821A DE19517821A1 (en) | 1995-05-18 | 1995-05-18 | Process for the production of caprolactam |
| DE19517821.1 | 1995-05-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2218132A1 true CA2218132A1 (en) | 1996-11-21 |
Family
ID=7761968
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002218132A Abandoned CA2218132A1 (en) | 1995-05-18 | 1996-05-07 | The preparation of caprolactam |
Country Status (20)
| Country | Link |
|---|---|
| EP (1) | EP0815077A1 (en) |
| JP (1) | JPH11505230A (en) |
| KR (1) | KR19990014859A (en) |
| CN (1) | CN1075810C (en) |
| AU (1) | AU700098B2 (en) |
| BG (1) | BG102027A (en) |
| BR (1) | BR9608470A (en) |
| CA (1) | CA2218132A1 (en) |
| CZ (1) | CZ289460B6 (en) |
| DE (1) | DE19517821A1 (en) |
| EA (1) | EA199700402A1 (en) |
| HU (1) | HU220356B (en) |
| MX (1) | MX9708676A (en) |
| NO (1) | NO307964B1 (en) |
| NZ (1) | NZ308485A (en) |
| PL (1) | PL323389A1 (en) |
| SK (1) | SK154897A3 (en) |
| TR (1) | TR199701385T1 (en) |
| TW (1) | TW340840B (en) |
| WO (1) | WO1996036600A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19738463C2 (en) * | 1997-09-03 | 1999-09-23 | Basf Ag | Process for the production of caprolactam |
| DE19738464A1 (en) * | 1997-09-03 | 1999-03-04 | Basf Ag | Use of moldings as a catalyst for the production of caprolactam |
| CN101890370B (en) * | 2010-08-05 | 2012-05-30 | 上海交通大学 | Nano-titanium dioxide and polyphosphazene based composite optical catalyst and preparation method thereof |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2029540A (en) * | 1935-10-01 | 1936-02-04 | Porteous William | Trailer |
| US2301964A (en) * | 1941-09-12 | 1942-11-17 | Du Pont | Method of preparing lactams |
| JPS4821958B1 (en) * | 1969-01-28 | 1973-07-02 | ||
| US4625023A (en) * | 1985-09-03 | 1986-11-25 | Allied Corporation | Selective conversion of aliphatic and aromatic aminonitriles and/or dinitriles into lactams |
| US4628085A (en) * | 1985-09-03 | 1986-12-09 | Allied Corporation | Use of silica catalyst for selective production of lactams |
| JP2969779B2 (en) * | 1990-05-01 | 1999-11-02 | 株式会社明電舎 | Shading image processing device |
| DE4339648A1 (en) * | 1993-11-20 | 1995-05-24 | Basf Ag | Process for the production of caprolactam |
-
1995
- 1995-05-18 DE DE19517821A patent/DE19517821A1/en not_active Withdrawn
-
1996
- 1996-05-02 TW TW085105277A patent/TW340840B/en active
- 1996-05-07 CA CA002218132A patent/CA2218132A1/en not_active Abandoned
- 1996-05-07 SK SK1548-97A patent/SK154897A3/en unknown
- 1996-05-07 AU AU58147/96A patent/AU700098B2/en not_active Ceased
- 1996-05-07 CZ CZ19973578A patent/CZ289460B6/en not_active IP Right Cessation
- 1996-05-07 TR TR97/01385T patent/TR199701385T1/en unknown
- 1996-05-07 MX MX9708676A patent/MX9708676A/en unknown
- 1996-05-07 BR BR9608470A patent/BR9608470A/en unknown
- 1996-05-07 WO PCT/EP1996/001891 patent/WO1996036600A1/en not_active Application Discontinuation
- 1996-05-07 KR KR1019970708204A patent/KR19990014859A/en not_active Application Discontinuation
- 1996-05-07 CN CN96194001A patent/CN1075810C/en not_active Expired - Fee Related
- 1996-05-07 PL PL96323389A patent/PL323389A1/en unknown
- 1996-05-07 NZ NZ308485A patent/NZ308485A/en unknown
- 1996-05-07 EP EP96919687A patent/EP0815077A1/en not_active Withdrawn
- 1996-05-07 EA EA199700402A patent/EA199700402A1/en unknown
- 1996-05-07 JP JP8534516A patent/JPH11505230A/en active Pending
- 1996-05-07 HU HU9801131A patent/HU220356B/en not_active IP Right Cessation
-
1997
- 1997-11-06 BG BG102027A patent/BG102027A/en unknown
- 1997-11-17 NO NO975268A patent/NO307964B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU5814796A (en) | 1996-11-29 |
| CN1075810C (en) | 2001-12-05 |
| EP0815077A1 (en) | 1998-01-07 |
| NZ308485A (en) | 2000-01-28 |
| CZ289460B6 (en) | 2002-01-16 |
| CZ357897A3 (en) | 1998-04-15 |
| BR9608470A (en) | 1998-12-29 |
| HU220356B (en) | 2001-12-28 |
| EA199700402A1 (en) | 1999-06-24 |
| JPH11505230A (en) | 1999-05-18 |
| SK154897A3 (en) | 1998-07-08 |
| TR199701385T1 (en) | 1998-04-21 |
| NO307964B1 (en) | 2000-06-26 |
| NO975268L (en) | 1997-11-17 |
| MX9708676A (en) | 1998-02-28 |
| WO1996036600A1 (en) | 1996-11-21 |
| NO975268D0 (en) | 1997-11-17 |
| HUP9801131A3 (en) | 1999-05-28 |
| DE19517821A1 (en) | 1996-11-21 |
| HUP9801131A2 (en) | 1998-08-28 |
| AU700098B2 (en) | 1998-12-24 |
| CN1184467A (en) | 1998-06-10 |
| PL323389A1 (en) | 1998-03-30 |
| KR19990014859A (en) | 1999-02-25 |
| TW340840B (en) | 1998-09-21 |
| BG102027A (en) | 1998-08-31 |
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