A method for preparing a partially fluorinated ester comprising acyl and alkoxy groups wherein the acyl group comprises a branched or linear fluorine containing C.sub.3-C.sub.8 group with one of the structures: (Formulae (I), (II)) wherein X and Y are independently selected from: —H, —CH.sub.3, —F, —Cl, —CH.sub.2F, —CF.sub.3—OCF.sub.3, —OCH.sub.2CF.sub.3, OCH.sub.2CF.sub.2CHF.sub.2 and —CH.sub.2CF.sub.3 (wherein both X and Y cannot be H) comprising reacting an unsaturated halocarbon: (Formula (III)) wherein A and B are independently selected from the group comprising —H, —CH.sub.3, —F, —Cl, —CH.sub.2F, —CF.sub.3, —OCF.sub.3, —OCH.sub.2CF.sub.3, OCH.sub.2CF.sub.2CHF.sub.2 and —CH.sub.2CF.sub.3 (wherein both A and B cannot be H) with carbon monoxide and an alcohol, in the presence of a catalyst methods.

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Provided is a compound with which a lubricant having excellent adhesion to a magnetic disk, particularly to a protective layer can be provided. A perfluoropolyether compound in accordance with one aspect of this invention has a structure in which two perfluoropolyethers are bonded to each other through an aliphatic ether, the aliphatic ether including a carbon atom to which a primary alcohol is bonded.

Provided is a compound with which a lubricant having excellent adhesion to a magnetic disk, particularly to a protective layer can be provided. A perfluoropolyether compound in accordance with one aspect of this invention has a structure in which two perfluoropolyethers are bonded to each other through an aliphatic ether, the aliphatic ether including a carbon atom to which a primary alcohol is bonded.

Disclosed is a fluoropolyether compound comprising a C.sub.4-10 aliphatic hydrocarbon chain present in the middle of the fluoropolyether compound and at least two perfluoropolyethers.

Disclosed is a fluoropolyether compound comprising a C.sub.4-10 aliphatic hydrocarbon chain present in the middle of the fluoropolyether compound and at least two perfluoropolyethers.

The present invention relates to a composition for cooling a propulsion system of an electric or hybrid vehicle, comprising: (i) at least one base oil, or at least one hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.; and (ii) at least one fire retardant corresponding to formula (I)
R.sub.F-L-R.sub.H  (I) in which R.sub.F is a perfluorinated or partially fluorinated group, R.sub.H is a hydrocarbon-based group, and L is a linker, said fire retardant of formula (I) being at least partially in an encapsulated form. The invention also relates to the use of at least one fire retardant of formula (I) which is at least partially in an encapsulated form in a composition for cooling a propulsion system of an electric or hybrid vehicle, including at least one battery, to give it ignition-resistance properties. Finally, the invention relates to a process for cooling and fire-protecting a battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery, in particular a lithium-ion or nickel-cadmium battery, in contact with a composition according to the invention.

A compound of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br, and I; X is independently selected from the group consisting of H, F, Cl, Br, and I; Y is independently selected from the group consisting of F, Cl, Br, and I; Z is independently selected from the group consisting of H, F, Cl, Br, and I; n is an integer from 1 to 8; and n′ is an integer from 1 to 12. ##STR00001##

A compound of formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br, and I; X is independently selected from the group consisting of H, F, Cl, Br, and I; Y is independently selected from the group consisting of F, Cl, Br, and I; Z is independently selected from the group consisting of H, F, Cl, Br, and I; n is an integer from 1 to 8; and n′ is an integer from 1 to 12. ##STR00001##

This fluorine-containing ether compound is a fluorine-containing ether compound represented by formula (1).

R.sup.1—X—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4  (1)

(In formula (1), R.sup.1 is an alkenyloxy group of 2 to 8 carbon atoms or an alkynyloxy group of 3 to 8 carbon atoms. R.sup.2 is represented by formula (2) shown below. In formula (2), a represents an integer of 1 to 3. X is represented by formula (3) shown below. In formula (3), b represents an integer of 1 to 5, Y is a divalent linking group that is bonded to a carbon atom in formula (2), and R represents an alkyl group of 1 to 6 carbon atoms or H. R.sup.3 represents a perfluoropolyether chain. R.sup.4 represents a terminal group containing two or three polar groups, wherein each polar group is bonded to a different carbon atom, and the carbon atoms to which the polar groups are bonded are bonded to each other via a linking group containing a carbon atom to which a polar group is not bonded.)

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High temperature lubricants for magnetic media are provided. One such lubricant includes fluoroalkyl, fluoroalkenyl, perfluoroalkyl, or perfluoroalkyl ether segments, anchoring functional groups engageable with a protective overcoat of a magnetic recording media, and cyclic functional groups. The lubricants can be used in conjunction with a magnetic recording medium and/or a magnetic data storage system.