US3668267A
Expired / Lapsed
US
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Separation of 2,7-dimethylnaphthalene from 2,6-dimethylnaphthalene with molecular sieves
Assignee: Sunoco Inc
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Filing: 1970-01-30
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Granted: 1972-06-06
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Expires: 1990-01-30
Abstract
Abstract Two structurally similar polycyclic compounds can be separated by contacting a fluid feed mixture containing said compounds with a partially dehydrated molecular sieve zeolite, the ratio Al/Si of the zeolite being in the range of 0.65-0.2. The polycyclic compounds can be heterocyclic or carbocyclic. For example, selective adsorption of 2,7-dimethylnaphthalene from a dimethylnaphthalene concentrate is obtained with sodium Type Y molecular sieves. 2,6-Dimethylnaphthalene can then be crystallized from the unadsorbed raffinate fraction. Separation factors of 6 to 8 are obtained, indicating the unexpected high selectivity of these particular molecular sieves for this adsorption (especially compared to Type X zeolite). A continuous method is disclosed for adsorption and desorption of 2,7-dimethylnaphthalene utilizing Type Y zeolite. Type L zeolite can be used for adsorption and desorption of 2,6-DMN.
Inventors
- 👤 John A Hedge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:22
CPC Classifications
C; C07; C07C; C07C7/00; C07C7/12; C07C7/13
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
26 words
Process according to claim 1 wherein from 25-100 percent of the electronegativity associated with the alumino-silicate framework of said zeolite is satisfied by cations of metals.
Claim 2
Dependent Claim
33 words
Process according to claim 2 wherein said cations of metals comprise one or more of the rare earths, lanthanium, lithium, sodium, potassium, calcium, magnesium, barium or mixtures of two or more such cations.
Claim 3
Dependent Claim
49 words
Process according to claim 1 wherein said substantially crystalline alumino-silicate zeolite is at least 50 percent crystalline by X-ray, compared to a fully hydrated pure specimen of said zeolite, and wherein there is a loss of 2-18 weight percent water upon ignition analysis of said zeolite at 1,900* F.
Claim 4
Dependent Claim
18 words
Process according to claim 4 wherein said loss of water upon ignition analysis is about 12 weight percent.
Claim 5
Dependent Claim
41 words
Process according to claim 1 wherein said fluid mixture is contacted in liquid phase and said two structurally similar polycyclic hydrocarbons are selected from the following pairs: 2, 6-Dimethylnaphthalene and 2,7-dimethylnaphthalene; octahydrophenanthrene and octahydroanthracene; anthracene and phenanthrene; and, fluorene and 5,6-benzindan.
Claim 6
Dependent Claim
27 words
Process according to claim 6 wherein said ratio Al/Si is in the range of 0.65-0.35 and wherein said critical pore diameter is in the range of 6.5-13A:
Claim 7
Dependent Claim
22 words
Process according to claim 7 wherein 2,7-dimethylnaphthalene is separated from 2,6-dimethylnaphthalene by preferrential adsorption of said 2,7-dimethylnaphthalene on a Type Y zeolite.
Claim 8
Dependent Claim
28 words
Process according to claim 8 wherein 2,6-dimethylnaphthalene is separated from a heart-cut from catalytic gas oil or from a heart-cut from an aromatic extract of catalytic gas oil.
Claim 9
Dependent Claim
123 words
Process wherein 2,6-dimethylnaphthalene is separated from 2, 7-dimethylnaphthalene by adsorption of said 2,6-dimethylnaphthalene on a Type L zeolite said process comprising A. contacting a fluid feed mixture comprising said 2,6- and 2,7-dimethylnaphthalenes with a solid adsorbant comprising a partially dehydrated, substantially crystalline alumino-silicate zeolite having a critical pore diameter greater than about 6A*, the ratio Al/Si of the alumino-silicate framework of said zeolite being in the range of 0.35-0.2 whereby there is obtained a rich adsorbent containing an adsorbate which is richer in 2,6-dimethylnaphthalene than was said fluid feed mixture, and a raffinate product which contains less of 2,6-dimethylnaphthalene than did said fluid feed mixture; B. separating said raffinate product from said rich adsorbent and, C. removing the 2,6-dimethylnaphthalene from said rich adsorbent.
Claim 10
Dependent Claim
26 words
Process according to claim 10 wherein from 25-100 percent of the electronegativity associated with the alumino-silicate framework of said zeolite is satisfied by cations of metals.
Claim 11
Dependent Claim
33 words
Process according to claim 10 wherein said cations of metals comprise one or more of the rare earths, lanthanium, lithium, sodium, potassium, calcium, magnesium, barium or mistures of two or more such cations.
Claim 12
Dependent Claim
49 words
Process according to claim 10 wherein said substantially crystalline aLumino-silicate zeolite is at least 50 percent crystalline by X-ray, compared to a fully hydrated pure specimen of said zeolite, and wherein there is a loss of 2-18 weight percent water upon ignition analysis of said zeolite at 1,900* F.
Claim 13
Dependent Claim
18 words
Process according to claim 13 wherein said loss of water upon ignition analysis is about 12 weight percent.
Claim 14
Dependent Claim
28 words
Process according to claim 10 wherein 2,6-dimethylnaphthalene is separated from a heart-cut from catalytic gas oil or from a heart-cut from an aromatic extract of catalytic gas oil.
Claim 15
Dependent Claim
16 words
Process according to claim 13 wherein said zeolite comprises the potassium form of Type L zeolite.
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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) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |