US4008148A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of insulating oil
Assignee: Eneos Corp
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Filing: 1975-04-30
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Granted: 1977-02-15
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Expires: 1995-04-30
Abstract
Abstract This invention provides a method for the preparation of insulating oil having good oxidation stability, electric characteristics and resistance to copper corrosion which comprises subjecting a distillate (stock) within a temperature range from 250 DEG to 400 DEG C. in terms of the boiling point at atmospheric pressure to solvent refining to a desulfurization from 30 to 75% by weight to give a raffinate, said distillate having been obtained either by distillation at atmospheric pressure of a paraffin- or mixture-base crude oil and/or by distillation under reduced pressure of a residual oil from the atmospheric pressure distillation, subjecting said raffinate to hydrogenating refining to a desulfurization from 40 to 90% by weight and subjecting the refined product to solvent dewaxing, and if necessary, subsequently subjecting the dewaxed product to clay treatment to a sulfur content of the final product from 0.1 to 0.35% by weight.
Inventors
- 👤 Midori Masunaga
- 👤 Yoshiki Kohno
- 👤 Tadashi Ohmori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:17
CPC Classifications
C; C10; C10G; C10G67/00; C10G67/02; C10G67/04; C10G2400/00; C10G2400/10; C10G2400/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
Method for the preparation of insulating oil having good oxidation stability, electric characteristics and resistance to copper corrosion which comprises subjecting a distillate within a temperature having a boiling range from 250° to 400° C. at atmospheric pressure to solvent refining to provide a raffinate oil in which 30 to 75% by weight of the sulfur present in the distillate is removed in said solvent refining step, said distillate having been obtained from a paraffin base crude oil or mixture base crude oil, subjecting said raffinate to hydrogenating refining with hydrogen and a hydrogenation catalyst to reduce from 40 to 90% by weight of the sulfur present in the raffinate and subjecting said hydrogenated oil to solvent dewaxing to provide said insulating oil having a sulfur content from 0.1 to 0.35 percent by weight.
Claim 2
Dependent Claim
134 words
Method for the preparation of insulating oil having good oxidation stability, electric characteristics and resistance to copper corrosion which comprises subjecting a distillate within a temperature having a boiling range from 250° to 400° C. at atmospheric pressure to solvent refining to provide a raffinate oil in which 30 to 75% by weight of the sulfur present in the distillate is removed in said solvent refining step, said distillate having been obtained from a paraffin base crude oil or mixture base crude oil, subjecting said raffinate to hydrogenating refining with hydrogen and a hydrogenation catalyst to reduce from 40 to 90% by weight of the sulfur present in the raffinate and subjecting said hydrogenated oil to solvent dewaxing to provide said insulating oil having a sulfur content from 0.1 to 0.35 percent by weight.
Claim 3
Dependent Claim
28 words
Method according to claim 1 wherein the solvent used for the solvent refining is one member selected from the group consisting of furfural, liquid sulfur dioxide and phenol.
Claim 4
Dependent Claim
79 words
Method according to claim 1 wherein the hydrogenating refining of the raffinate is carried out at a temperature from 230° to 350° C. under a pressure from 25 to 100 kg./cm. 2 using as the catalyst oxides of at least one metal selected from the group consisting of metals of Groups VI, IB and VIII in the Periodic Table on a carrier selected from the group consisting of bauxite, active carbon, fuller's earth, diatomaceous earth, zeolite, silica and silica-alumina.
Claim 5
Dependent Claim
25 words
Method according to claim 1 wherein the solvent used for the solvent dewaxing is a benzene-toluene-acetone solvent mixture or a benzene-toluene-methyl ethyl ketone solvent mixture.
Claim 6
Dependent Claim
35 words
Method according to claim 1 wherein the clay treatment is carried out with active clay at a temperature from 60° to 80° C. for a contact period of time from 30 minutes to 1 hour.
Claim 7
Dependent Claim
31 words
The method of claim 1, wherein the dewaxed product is subjected to a clay treatment to provide a final product having a sulfur content of from 0.1 to 0.35% by weight.
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) | 1980-02-15 | 1980-08-16 | 1981-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-15 | 1984-08-16 | 1985-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-15 | 1988-08-16 | 1989-02-15 | $7700.00 | Window Closed / Lapsed |