US4076577A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the separation of residues of toluenediisocyanate production
Assignee: BASF Corp
•
Filing: 1975-11-03
•
Granted: 1978-02-28
•
Expires: 1995-11-03
Abstract
Abstract A process for the separation of residues of toluenediisocyanate production from mixtures containing high boiling residues, toluenediisocyanate and solvent by evaporation in said residue at a minimum of 5° C above the boiling point of the higher boiling of the components consisting of toluenediisocyanate and solvent. The mixture is fed into the central portion of an evaporator equipped with a helical agitator operative to provide a material flow moving centrally downwards and peripherally upwards.
Inventors
- 👤 Eckard Hetzel
- 👤 Waldemar Koehler
- 👤 Georg Friedrich Vock
- 👤 Rolf Bittler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:44
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18; C07C263/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
A method of separating residues from a mixture of (1) residues and (2) toluenediisocyanate and solvent, said mixture being obtained by reaction of toluenediamine with phosgene in the presence of organic solvent, comprising the steps of feeding the mixture to the central portion of an evaporator equipped with a helical agitator, said evaporator being partly filled with residue and the temperature therein being maintained at least 5° C higher than the boiling point of the higher boiling component of the class consisting of toluenediisocyanate and solvent present in the mixture at the pressure within the evaporator, agitating the mixture by rotating said helical agitator at a speed of 2-100 rpm. while the mixture is fed to said evaporator, and removing the volatile components of the mixture from the evaporator in vapor form.
Claim 2
Independent Claim
132 words
A method of separating residues from a mixture of (1) residues and (2) toluenediisocyanate and solvent, said mixture being obtained by reaction of toluenediamine with phosgene in the presence of organic solvent, comprising the steps of feeding the mixture to the central portion of an evaporator equipped with a helical agitator, said evaporator being partly filled with residue and the temperature therein being maintained at least 5° C higher than the boiling point of the higher boiling component of the class consisting of toluenediisocyanate and solvent present in the mixture at the pressure within the evaporator, agitating the mixture by rotating said helical agitator at a speed of 2-100 rpm. while the mixture is fed to said evaporator, and removing the volatile components of the mixture from the evaporator in vapor form.
Claim 3
Dependent Claim
35 words
A method of separating residues as defined in claim 1, in which the mixture is fed from the top and the helical agitator is formed to cause material flow movement centrally downwards and peripherally upwards.
Claim 4
Dependent Claim
34 words
A method of separating residues as defined in claim 2, in which residue is removed from a peripheral location near the upper surface thereof during the step of feeding the mixture to the evaporator.
Claim 5
Dependent Claim
30 words
A method of separating residues as defined in claim 3, in which a substantial amount of heated residue is maintained in the evaporator during the entire addition of said mixture.
Claim 6
Dependent Claim
38 words
A method of separating residues as defined in claim 1, in which the product is recovered and the other volatiles removed in the evaporator are recycled to the process for preparing toluenediisocyanate from whence the mixture is obtained.
Claim 7
Dependent Claim
24 words
A method of separating residues as defined in claim 1, in which the evaporator is at subatmospheric pressure during the removal of volatile components.
Claim 8
Dependent Claim
27 words
A method of separating residues as defined in claim 1, in which the mixture contains solvent having a boiling point lower than the boiling point of toluenediisocyanate.
Claim 9
Dependent Claim
40 words
A method of separating residues as defined in claim 7, in which the temperature within the evaporator is maintained between about 30° C and 80° C higher than the boiling point of toluenediisocyanate at the pressure conditions within the evaporator.
Claim 10
Dependent Claim
27 words
A method of separating residues as defined in claim 1, in which the mixture contains solvent having a boiling point higher than the boiling point of toluenediisocyanate.
Claim 11
Dependent Claim
41 words
A method of separating residues as defined in claim 9, in which the temperature within the evaporator is maintained between about 30° C and 80° C higher than the boiling point of the solvent at the pressure conditions within the evaporator.
Claim 12
Dependent Claim
48 words
A method of separating residues as defined in claim 1, in which the mixture is fed at a rate sufficiently slow that substantially all of the volatile components thereof are vaporized from the added mixture before the currents carrying the added mixture reach the walls of the evaporator.
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) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |