Patent US4542447A successfully refreshed from Google Patents.
Patent US4769454A successfully refreshed from Google Patents.
US4769454A
Expired / Lapsed
US
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Process for the preparation of N-methylol-caprolactam
Assignee: Bayer AG
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Filing: 1988-01-06
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Granted: 1988-09-06
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Expires: 2008-01-06
Abstract
Abstract The process for the preparation of N-methylolcaprolactam through reaction of caprolactam with formaldehyde in the presence of an alkaline catalyst at elevated temperature is essentially improved when the reaction is carried out substantially solvent-free at 70° to 100° C. In an advantageous fashion, the alkaline catalyst used is in heterogeneous form. In a furthermore advantageous fashion, seed crystals of pure N-methylolcaprolactam are added to the reaction batch after cooling to a temperature below the melting point of pure N-methylol-caprolactam.
Inventors
- 👤 Heinz-Ulrich Blank
- 👤 Wolfgang Bauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:03
CPC Classifications
C; C07; C07D; C07D223/00; C07D223/02; C07D223/06; C07D223/08; C07D223/10
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
43 words
A process for the preparation of N-methylol-caprolactam (N-hydroxymethyl-caprolactam) through reaction of caprolactam with anhydrous formaldehyde in the presence of an alkaline catalyst at elevated temperature, characterized in that the reaction is carried out substantially solvent-free at a temperature of 70° to 100° C.
Claim 2
Dependent Claim
43 words
A process for the preparation of N-methylol-caprolactam (N-hydroxymethyl-caprolactam) through reaction of caprolactam with anhydrous formaldehyde in the presence of an alkaline catalyst at elevated temperature, characterized in that the reaction is carried out substantially solvent-free at a temperature of 70° to 100° C.
Claim 3
Dependent Claim
22 words
A process according to claim 1, characterized in that the reaction is carried out at a temperature of 70° to 90° C.
Claim 4
Dependent Claim
21 words
A process according to claim 2, characterized in that the reaction is carried out at a temperature of 70° to 80°.
Claim 5
Dependent Claim
59 words
A process according to claim 1, characterized in that carrying out the process substantially solvent-free includes using up to 10% of weight of an OH group-containing solvent or using up to 20% by weight of an aprotic solvent or using a mixture of such solvents, in each case relative to the total reaction batch, or omitting solvents or diluents.
Claim 6
Dependent Claim
30 words
A process according to claim 4, characterized in that up to 20% of weight of an aprotic solvent are employed or the use of a solvent or diluent is omitted.
Claim 7
Dependent Claim
18 words
A process according to claim 5, characterized in that the use of a solvent or diluent is omitted.
Claim 8
Dependent Claim
48 words
A process according to claim 1, characterized in that the alkaline catalyst is a hydroxide of an alkali or an alkaline-earth metal, an alkali salt of a weak inorganic acid or a tertiary aliphatic amine in an amount of from 0.1 to 2.5 mole %, relative to caprolactam.
Claim 9
Dependent Claim
21 words
A process according to claim 7, characterized in that the catalyst is an alkali metal salt of a weak inorganic acid.
Claim 10
Dependent Claim
16 words
A process according to claim 8, characterized in that the catalyst is an alkali metal carbonate.
Claim 11
Dependent Claim
14 words
A process according to claim 9, characterized in that the catalyst is potassium carbonate.
Claim 12
Dependent Claim
25 words
A process according to claim 7, characterized in that the catalyst is employed in an amount from 0.25 to 1.5 mole %, relative to caprolactam.
Claim 13
Dependent Claim
26 words
A process according to claim 11, characterized in that the catalyst is employed in an amount of from 0.5 to 1 mole %, relative to caprolactam.
Claim 14
Dependent Claim
16 words
A process according to claim 7, characterized in that the catalyst is present in heterogeneous form.
Claim 15
Dependent Claim
32 words
A process according to claim 1, characterized in that seed crystals of pure N-methylol-caprolactam are added to the reaction batch after cooling to a temperature below the melting point of pure N-methylol-caprolactam.
Claim 16
Dependent Claim
29 words
A process according to claim 14, characterized in that the seed crystals are added in an amount of less than 10% by weight, relative to the total reaction batch.
Claim 17
Dependent Claim
29 words
A process according to claim 15, characterized in that the seed crystals are added in an amount from 0.0001 to 10% by weight, relative to the total reaction batch.
Claim 18
Dependent Claim
29 words
A process according to claim 16, characterized in that the seed crystals are added in an amount from 0.001 to 5% by weight, relative to the total reaction batch.
Claim 19
Dependent Claim
21 words
A process according to claim 15, characterized in that the seed crystals are added at a maximum temperature of 65° C.
Claim 20
Dependent Claim
22 words
A process according to claim 18, characterized in that the seed crystals are added at a temperature of 10° to 65° C.
Claim 21
Dependent Claim
22 words
A process according to claim 19, characterized in that the seed crystals are added at a temperature of 20° to 60° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |