US4409419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing 2,5-dimethyl-2,4-hexadiene
Assignee: Anic SpA
•
Filing: 1981-08-06
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Granted: 1983-10-11
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Expires: 2001-08-06
Abstract
Abstract 2,5-Dimethyl-2,4-hexadiene is prepared by dehydrating 2,5-dimethyl-2,5-hexanediol in liquid phase. The reaction takes place by contacting 2,5-dimethyl-2,5-hexanediol, melted or dissolved in an appropriate solvent, with acids, heating the mixture at a temperature of 100° C.-160° C. and distilling off water from the reaction environment as it is being formed. The pressure can range between 1 and 10 bars.
Inventors
- 👤 Aldo Prevedello
- 👤 Edoardo Platone
- 👤 Morello Morelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:51
CPC Classifications
C; C07; C07C; C07C1/00; C07C1/20; C07C1/24; C07C2521/00; C07C2521/02; C07C2527/00; C07C2527/02; C07C2527/053; C07C2527/054; C07C2527/055; C07C2527/06; C07C2527/08; C07C2527/14; C07C2527/16; C07C2527/167; C07C2527/173; C07C2531/00; C07C2531/02; C07C2531/025; C07C2531/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
74 words
A process for the preparation of 2,5-dimethyl-2,4-hexadiene comprising the steps of contacting 2,5-dimethyl-2,5-hexanediol in liquid phase or in aqueous solutions thereof with an acid, derivatives of said acid or substances which form free acids, heating the mixture thus obtained to a temperature in a range of from about 100° C. to about 160° C., distilling off water as it is formed, recycling the organic phase, and separating the 2,5-dimethyl-2,4-hexadiene obtained from the reaction mixture.
Claim 2
Dependent Claim
74 words
A process for the preparation of 2,5-dimethyl-2,4-hexadiene comprising the steps of contacting 2,5-dimethyl-2,5-hexanediol in liquid phase or in aqueous solutions thereof with an acid, derivatives of said acid or substances which form free acids, heating the mixture thus obtained to a temperature in a range of from about 100° C. to about 160° C., distilling off water as it is formed, recycling the organic phase, and separating the 2,5-dimethyl-2,4-hexadiene obtained from the reaction mixture.
Claim 3
Dependent Claim
25 words
Process according to claim 1 wherein the mixture is heated to a temperature in a range of from about 100° C. to about 140° C.
Claim 4
Dependent Claim
25 words
Process according to claim 1 wherein the reaction is carried out at a pressure in a range of from about 1 to about 10 bars.
Claim 5
Dependent Claim
34 words
Process according to claim 1 wherein the acid is selected from the group consisting of phosphoric acid, polyphosphoric acid, phosphorous pentoxide, sulfuric acid, boric acid, hydrobromic acid, potassium sulfate, oxalic acid and toluenesulfonic acid.
Claim 6
Dependent Claim
33 words
Process according to claim 1 wherein the acid is selected from the group consisting of polyphosphoric acid and phosphoric acid having a concentration in a range of from about 75% to about 99%.
Claim 7
Dependent Claim
29 words
Process according to claim 1 wherein the acid is employed in an amount in a range of from about 1% to about 50% by weight relative to the 2,5-dimethyl-2,5-hexanediol.
Claim 8
Dependent Claim
29 words
Process according to claim 1 wherein the acid is employed in an amount in a range of from about 3% to about 30% by weight relative to the 2,3-dimethyl-2,5-hexanediol.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |