Patent US3857903A successfully refreshed from Google Patents.
US3857903A
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Continuous process for the preparation of 2,5-dimethyl-2,4-hexadiene
Assignee: Eastman Kodak Co
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Filing: 1972-10-18
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Granted: 1974-12-31
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Expires: 1992-10-18
Abstract
Abstract 1,1,4,4-tetraalkyl-1,3-butadienes are prepared by the acid catalyzed cleavage and isomerization of a carboxylic acid ester having the formula WHERE R is an organic radical such that the product organic acid forms an azeotrope with the product 1,1,4,4-tetraalkyl-1,3butadiene, R1 through R7 are the same or different lower alkyl radicals, and R8 is a lower alkylidene radical, in a process which comprises continuously contacting an acid catalyst at a temperature in the range of about 125*C. to about 250*C. with said carboxylic acid ester and subsequently continuously removing from the reactor an overhead stream comprising 1,1,4,4tetraalkyl-1,3-butadiene and an organic acid, distilling said overhead stream in a first distillation column at a pressure of less than one atmosphere, removing therefrom a second overhead stream comprising 1,1,4,4-tetraalkyl-1,3-butadiene, distilling said second overhead stream at a pressure higher than that of the first distillation column and removing therefrom a bottoms stream comprising 1,1,4,4-tetraalkyl-1,3-butadiene, and distilling said bottoms stream also at a pressure higher than that of the first distillation column so as to obtain a stream of essentially pure 1,1,4,4-tetraalkyl-1,3-butadiene. OR D R A W I N G
Inventors
- 👤 H Hagemeyer
- 👤 H Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:19
CPC Classifications
C; C07; C07C; C07C11/00; C07C11/12; C07C1/00; C07C1/20; C07C1/207; C07C1/213; C07C7/00; C07C7/04; C07C2531/00; C07C2531/02; C07C2531/025
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
49 words
A PROCESS FOR THE PRODUCTION OF 2,5-DIMETHYL-2,4HEXADIENE BY THE ACID CATALYZED CLEAVAGE AND ISOMERIZATION OF 2,2,4-TRIMETHYL-3-PENTYL ISOBUTYRATE AND/OR 2,2,4-TRIMETHYL4-PENTYL ISOBUTYRATE BY CONTACTING AN ACID CATALYST AT A TEMPERATURE IN THE RANGE OF ABOUT 125*C TO ABOUT 250*C WITH SAID CARBOXYLIC ACID ESTER, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF:
Claim 2
Dependent Claim
49 words
A PROCESS FOR THE PRODUCTION OF 2,5-DIMETHYL-2,4HEXADIENE BY THE ACID CATALYZED CLEAVAGE AND ISOMERIZATION OF 2,2,4-TRIMETHYL-3-PENTYL ISOBUTYRATE AND/OR 2,2,4-TRIMETHYL4-PENTYL ISOBUTYRATE BY CONTACTING AN ACID CATALYST AT A TEMPERATURE IN THE RANGE OF ABOUT 125*C TO ABOUT 250*C WITH SAID CARBOXYLIC ACID ESTER, THE IMPROVEMENT WHICH COMPRISES THE STEPS OF:
Claim 3
Dependent Claim
16 words
CONTINOUSLY FEEDING SAID CARBOXYLIC ACID ESTER AND SAID ACID CATALYST INTO THE BASE OF A REACTOR;
Claim 4
Dependent Claim
16 words
CONTINOUSLY FEEDING SAID CARBOXYLIC ACID ESTER AND SAID ACID CATALYST INTO THE BASE OF A REACTOR;
Claim 5
Dependent Claim
14 words
CONTINOUSLY REMOVING FROM THE REACTOR A FIRST OVERHEAD STREAM COMPRISNG 2,5-DIMETHYL:2,4-HEXADIENE AND ISOBUTYRIC ACID;
Claim 6
Dependent Claim
14 words
CONTINOUSLY REMOVING FROM THE REACTOR A FIRST OVERHEAD STREAM COMPRISNG 2,5-DIMETHYL:2,4-HEXADIENE AND ISOBUTYRIC ACID;
Claim 7
Dependent Claim
14 words
continuously removing from the reactor a first overhead stream comprising 2,5-dimethyl-2,4-hexadiene and isobutyric acid;
Claim 8
Dependent Claim
14 words
continuously removing from the reactor a first overhead stream comprising 2,5-dimethyl-2,4-hexadiene and isobutyric acid;
Claim 9
Dependent Claim
29 words
A process according to claim 1 wherein the acid catalyst has a pH of no more than 3 when dispersed in water at a concentration of 1% by weight.
Claim 10
Dependent Claim
15 words
A process according tO claim 1 wherein the acid catalyst is an aromatic sulfonic acid.
Claim 11
Dependent Claim
37 words
continuously feeding said first overhead stream into a first distillation column operated at a pressure of less than one atmosphere, and removing therefrom a second overhead stream comprising 2,5-dimethyl-2,4-hexadiene and a first bottoms stream comprising isobutyric acid;
Claim 12
Dependent Claim
37 words
continuously feeding said first overhead stream into a first distillation column operated at a pressure of less than one atmosphere, and removing therefrom a second overhead stream comprising 2,5-dimethyl-2,4-hexadiene and a first bottoms stream comprising isobutyric acid;
Claim 13
Dependent Claim
37 words
CONTINOUSLY FEEDING SAID FIRST OVERHEAD STREAM INTO A FIRST DISTILLATION COLUMN OPERATED AT A PRESSURE OF LESS THAN ONE ATMOSPHERE, AND REMOVING THEREFROM, A SECOND OVERHEAD STREAM COMPRISING 2,5-DIMETHYL-2,4-HEXADIENE AND A FIRST BOTTOMS STREAM COMPRISING ISOBUTYRIC ACID;
Claim 14
Dependent Claim
37 words
CONTINOUSLY FEEDING SAID FIRST OVERHEAD STREAM INTO A FIRST DISTILLATION COLUMN OPERATED AT A PRESSURE OF LESS THAN ONE ATMOSPHERE, AND REMOVING THEREFROM, A SECOND OVERHEAD STREAM COMPRISING 2,5-DIMETHYL-2,4-HEXADIENE AND A FIRST BOTTOMS STREAM COMPRISING ISOBUTYRIC ACID;
Claim 15
Dependent Claim
45 words
FEEDING SAID SECOND OVERHEAD STREAM INTO A SECOND DISTILLATION COLUMN, WHICH COLUMN IS OPERATED AT A PRESSURE HIGHER THAN THAT OF THE FIRST DISTILLATION COLUMN AND REMOVING THEREFROM A THIRD OVERHEAD STREAM CONSISTING OF LOW-BOILING IMPURITIES, AND A SECOND BOTTOMS STREAM COMPRISING INPUTE 2-5-DIMETHYL-2,4-HEXADIENE, AND
Claim 16
Dependent Claim
45 words
FEEDING SAID SECOND OVERHEAD STREAM INTO A SECOND DISTILLATION COLUMN, WHICH COLUMN IS OPERATED AT A PRESSURE HIGHER THAN THAT OF THE FIRST DISTILLATION COLUMN AND REMOVING THEREFROM A THIRD OVERHEAD STREAM CONSISTING OF LOW-BOILING IMPURITIES, AND A SECOND BOTTOMS STREAM COMPRISING INPUTE 2-5-DIMETHYL-2,4-HEXADIENE, AND
Claim 17
Dependent Claim
45 words
feeding said second overhead stream into a second distillation column, which column is operated at a pressure higher than that of the first distillation column and removing therefrom a third overhead stream consisting of low-boiling impurities, and a second bottoms stream comprising impure 2,5-dimethyl-2,4-hexadiene; and
Claim 18
Dependent Claim
45 words
feeding said second overhead stream into a second distillation column, which column is operated at a pressure higher than that of the first distillation column and removing therefrom a third overhead stream consisting of low-boiling impurities, and a second bottoms stream comprising impure 2,5-dimethyl-2,4-hexadiene; and
Claim 19
Dependent Claim
16 words
A process according to claim 1 in which the acid catalyst is an aliphatic sulfonic acid.
Claim 20
Dependent Claim
13 words
A process according to claim 1 wherein the acid catalyst is paratoluenesulfonic acid.
Claim 21
Dependent Claim
52 words
feeding said second bottoms stream into a third distillation column, which column is operated at a pressure higher than that of the first distillation column and removing from said third distillation column a stream of essentially pure 2,5-dimethyl-2,4-hexadiene from a vapor take-off line located near the bottom of said third distillation column.
Claim 22
Dependent Claim
52 words
feeding said second bottoms stream into a third distillation column, which column is operated at a pressure higher than that of the first distillation column and removing from said third distillation column a stream of essentially pure 2,5-dimethyl-2,4-hexadiene from a vapor take-off line located near the bottom of said third distillation column.
Claim 23
Dependent Claim
53 words
FEEDING SAID SECOND BOTTOMS STREAM INTO A THIRD DISTILLATION COLUMN, WHICH COLUMN IS OPERATED AT A PRESSURE HIGHER THAN THAT OF THE FIRST DISTILLATION COLUMN AND REMOVING FROM SAID THIRD DISTILLATION COLUMN AND A STREAM OF ESSENTIALLY PURE 2,5-DIMETHYL-2,4-HEXADIENE FROM A VAPOR TAKE-OFF LINE LOCATED NEAR THE BOTTOM OF SAID THIRD DISTILLATION COLUMN.
Claim 24
Dependent Claim
53 words
FEEDING SAID SECOND BOTTOMS STREAM INTO A THIRD DISTILLATION COLUMN, WHICH COLUMN IS OPERATED AT A PRESSURE HIGHER THAN THAT OF THE FIRST DISTILLATION COLUMN AND REMOVING FROM SAID THIRD DISTILLATION COLUMN AND A STREAM OF ESSENTIALLY PURE 2,5-DIMETHYL-2,4-HEXADIENE FROM A VAPOR TAKE-OFF LINE LOCATED NEAR THE BOTTOM OF SAID THIRD DISTILLATION COLUMN.
Claim 25
Dependent Claim
14 words
A process according to claim 1 wherein the carboxylic acid ester is 2,2,4-trimethyl-3-pentenyl isobutyrate.
Claim 26
Dependent Claim
14 words
A process according to claim 1 wherein the carboxylic acid ester is 2,2,4-trimethyl-4-pentenyl isobutyrate.
Claim 27
Dependent Claim
23 words
A process according to claim 1 wherein the first distillation column is operated at a pressure less than about 175 mm of Hg.
Claim 28
Dependent Claim
29 words
A process according to claim 8 wherein the first distillation column is operated at a pressure of from about 13 mm of Hg to about 35 mm of Hg.
Claim 29
Dependent Claim
17 words
A process according to claim 1 wherein the second distillation column is operated at substantially atmospheric pressure.
Claim 30
Dependent Claim
17 words
A process according to claim 1 wherein the third distillation column is operated at substantially atmospheric pressure.
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) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |