US4367349A
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US
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Liquid phase synthesis of hexafluoroisobutylene
Assignee: Honeywell International Inc
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Filing: 1981-06-18
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Granted: 1983-01-04
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Expires: 2001-06-18
Abstract
Abstract The process for preparing hexafluoroisobutylene is disclosed which comprises reacting, in the liquid phase, formaldehyde or a formaldehyde-generating compound with hexafluorothioacetone dimer in an aprotic solvent containing at least a catalytic amount of an alkali metal fluoride or a sulfonic acid having general formula RSO3H is disclosed. The preferred aprotic solvents are dimethylformamide, N-methyl pyrrolidone and dimethyl sulfoxide. The preferred alkali metal fluoride is KF; the preferred sulfonic acids are CH3SO3H and p-CH3C6H4SO3H. The production of hexafluoroisobutylene by contacting hexafluoropropene with elemental sulfur and a catalytic amount of an alkali metal fluoride such as KF in an aprotic solvent such as dimethyl sulfoxide or N-methyl pyrrolidone at a temperature of between about 40 DEG and about 70 DEG C. for a time sufficient to produce hexafluorothioacetone dimer combined with contacting said dimer in said aprotic solvent containing said alkali metal fluoride at a temperature between about 100 DEG C. and 150 DEG C. for a time sufficient to produce an effluent stream containing hexafluoroisobutylene which is recovered therefrom is also disclosed.
Inventors
- 👤 Louis G. Anello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:26
CPC Classifications
C; C07; C07D; C07D339/00; C07C; C07C17/00; C07C17/361
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
144 words
A process for the preparation of hexafluoroisobutylene which comprises reacting, in the liquid phase, hexafluorothioacetone dimer with formaldehyde or a formaldehyde-generating compound in an aprotic solvent containing at least a catalytic amount of an alkali metal fluoride or a sulfonic acid having the formula RSO 3 H wherein R is an organic radical selected from the group consisting of straight and branched chain alkyl groups having one to fourteen carbon atoms, aryl groups having six to ten carbon atoms, monoalkylaryl groups wherein alkyl is a straight or branched chain carbon group having one to fourteen carbon atoms and wherein aryl is an aromatic group containing six to ten carbon atoms, and dialkylaryl wherein each alkyl group is independently a straight or branched chain organic group having one to fourteen carbon atoms and wherein aryl is an aromatic group containing six to ten carbon atoms.
Claim 2
Dependent Claim
144 words
A process for the preparation of hexafluoroisobutylene which comprises reacting, in the liquid phase, hexafluorothioacetone dimer with formaldehyde or a formaldehyde-generating compound in an aprotic solvent containing at least a catalytic amount of an alkali metal fluoride or a sulfonic acid having the formula RSO 3 H wherein R is an organic radical selected from the group consisting of straight and branched chain alkyl groups having one to fourteen carbon atoms, aryl groups having six to ten carbon atoms, monoalkylaryl groups wherein alkyl is a straight or branched chain carbon group having one to fourteen carbon atoms and wherein aryl is an aromatic group containing six to ten carbon atoms, and dialkylaryl wherein each alkyl group is independently a straight or branched chain organic group having one to fourteen carbon atoms and wherein aryl is an aromatic group containing six to ten carbon atoms.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein hexafluorothioacetone dimer is reacted with formaldehyde.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein hexafluorothioacetone dimer is reacted with paraformaldehyde.
Claim 5
Dependent Claim
12 words
The process of claim 1 wherein hexafluorothioacetone dimer is reacted with α-trioxane.
Claim 6
Dependent Claim
14 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethylformamide.
Claim 7
Dependent Claim
15 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethyl sulfoxide.
Claim 8
Dependent Claim
15 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is N-methyl pyrrolidone.
Claim 9
Dependent Claim
30 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethylformamide which contains at least about 0.06 moles of KF per about one mole of hexafluorothioacetone dimer.
Claim 10
Dependent Claim
35 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethyl sulfoxide which contains at least about 0.06 moles of CH 3 SO 3 H per about one mole of hexafluorothioacetone dimer.
Claim 11
Dependent Claim
34 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethylformamide which contains at least about 0.06 moles of CH 3 SO 3 H per about one mole of hexafluorothioacetone dimer.
Claim 12
Dependent Claim
38 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethylformamide which contains at least about 0.06 moles of p-CH 3 C 6 H 4 SO 3 H per about one mole of hexafluorothioacetone dimer.
Claim 13
Dependent Claim
31 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethyl sulfoxide which contains at least about 0.06 moles of KF per about one mole of hexafluorothioacetone dimer.
Claim 14
Dependent Claim
38 words
The process of claim 2, 3 or 4 wherein the aprotic solvent is dimethyl sulfoxide which contains at least about 0.06 moles of p-CH 3 C 6 H 4 SO 3 H per one mole of hexafluorothioacetone dimer.
Claim 15
Dependent Claim
24 words
The process of claim 2, 3 or 4 wherein the molar ratio of hexafluorothioacetone dimer:formaldehyde or formaldehyde-generating compound is about 1:2 to about 1:4.
Claim 16
Dependent Claim
137 words
A process for the preparation of hexafluoroisobutylene which comprises: (a) contacting hexafluoropropene with elemental sulfur and a catalytic amount of an alkali metal fluoride in an aprotic solvent selected from the group consisting of dimethylacetamide, dimethylformamide, dimethyl sulfoxide and N-methyl pyrrolidone while maintaining the temperature of the contacting between about 40° and 70° C. for a time sufficient to produce hexafluorothioacetone dimer; (b) contacting each mole of said hexafluorothioacetone dimer in said aprotic solvent containing said alkali metal fluoride with at least two moles of formaldehyde or formaldehyde-generating compound at a temperature between about 100° and 150° C. and optionally adding additional alkali metal fluoride; (c) maintaining the temperature of the contacting between about 100° and 150° C. for a time sufficient to produce hexafluoroisobutylene in an effluent stream; and (d) recovering hexafluoroisobutylene from said effluent stream.
Claim 17
Dependent Claim
137 words
A process for the preparation of hexafluoroisobutylene which comprises: (a) contacting hexafluoropropene with elemental sulfur and a catalytic amount of an alkali metal fluoride in an aprotic solvent selected from the group consisting of dimethylacetamide, dimethylformamide, dimethyl sulfoxide and N-methyl pyrrolidone while maintaining the temperature of the contacting between about 40° and 70° C. for a time sufficient to produce hexafluorothioacetone dimer; (b) contacting each mole of said hexafluorothioacetone dimer in said aprotic solvent containing said alkali metal fluoride with at least two moles of formaldehyde or formaldehyde-generating compound at a temperature between about 100° and 150° C. and optionally adding additional alkali metal fluoride; (c) maintaining the temperature of the contacting between about 100° and 150° C. for a time sufficient to produce hexafluoroisobutylene in an effluent stream; and (d) recovering hexafluoroisobutylene from said effluent stream.
Claim 18
Dependent Claim
19 words
The process of claim 15 wherein the alkali metal fluoride is KF which is added only in step (a).
Claim 19
Dependent Claim
21 words
The process of claim 15 wherein the alkali metal fluoride is KF which is added in step (a) and step (b).
Claim 20
Dependent Claim
11 words
The process of claim 16 wherein the aprotic solvent is dimethylformamide.
Claim 21
Dependent Claim
12 words
The process of claim 16 wherein the aprotic solvent is dimethyl sulfoxide.
Claim 22
Dependent Claim
12 words
The process of claim 16 wherein the aprotic solvent is N-methyl pyrrolidone.
References Cited (Backward Citations)
US3894097A
Cited
US4244891A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-03 | 1986-07-05 | 1987-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-03 | 1990-07-05 | 1991-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-03 | 1994-07-05 | 1995-01-04 | $7700.00 | Window Closed / Lapsed |