A lubricating agent including an ionic liquid formed from a Bronsted acid (HX) and a Bronsted base (B), wherein the Bronsted base has a linear hydrocarbon group having 10 or more carbon atoms and the difference between the pKa value of the Bronsted acid in water and the pKa value of the Bronsted base in water is 12 or more.

A lubricating agent including an ionic liquid formed from a Bronsted acid (HX) and a Bronsted base (B), wherein the Bronsted base has a linear hydrocarbon group having 10 or more carbon atoms and the difference between the pKa value of the Bronsted acid in water and the pKa value of the Bronsted base in water is 12 or more.

A low transition temperature mixture (LTTM) or deep eutectic solvent (DES) useful as a lubricating oil base stock and lubricating oil including a eutectic mixture of at least a first component and at least a second component. The at least first component comprises a hydrogen bond acceptor and the at least second component comprises a hydrogen bond donor. The eutectic mixture includes an equilibrium phase between the at least first component and the at least second component. The equilibrium phase does not exhibit physical characteristics of the at least first component in an unmixed state and the at least second component in an unmixed state. The at least first component and the at least second component form an intermolecular interaction between each other sufficient to prevent crystallization of the at least first component and the at least second component in the eutectic mixture. The eutectic mixture is a liquid at 20 C.

A low transition temperature mixture (LTTM) or deep eutectic solvent (DES) useful as a lubricating oil base stock and lubricating oil including a eutectic mixture of at least a first component and at least a second component. The at least first component comprises a hydrogen bond acceptor and the at least second component comprises a hydrogen bond donor. The eutectic mixture includes an equilibrium phase between the at least first component and the at least second component. The equilibrium phase does not exhibit physical characteristics of the at least first component in an unmixed state and the at least second component in an unmixed state. The at least first component and the at least second component form an intermolecular interaction between each other sufficient to prevent crystallization of the at least first component and the at least second component in the eutectic mixture. The eutectic mixture is a liquid at 20 C.

A lubricant which includes an ionic liquid including a conjugate acid and a conjugate base having 2 or more anions in a molecule of the conjugate base, wherein the conjugate acid has a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and a pKa of an acid that is a source of the conjugate base in acetonitrile is 10 or less.

A lubricant which includes an ionic liquid including a conjugate acid and a conjugate base having 2 or more anions in a molecule of the conjugate base, wherein the conjugate acid has a group including a straight-chain hydrocarbon group having 6 or more carbon atoms, and a pKa of an acid that is a source of the conjugate base in acetonitrile is 10 or less.

The present invention provides a steel wire rod having a lubricating coating film, which can achieve both workabilities such as wire drawability, spike property and ball ironing property, and corrosion resistance such as long-term rust prevention property; and a method for producing the same. Disclosed are a steel wire rod having a coating film containing no phosphorus, wherein the coating film includes a lower layer coating film composed of oxide and/or hydroxide of zirconium and having a film thickness of 1.0 to 200 nm, and an upper layer coating film containing silicon and tungsten, in order from a steel wire rod side, a mass ratio of tungsten/silicon being in a range of 1.3 to 18; and a method for producing the above steel wire rod, which includes bringing an aqueous chemical conversion treatment solution, which has a pH in a range of 2.5 to 5.0 and contains a water-soluble zirconium compound dissolved therein, into contact with a surface of a steel wire rod to form a lower layer coating film.

A low transition temperature mixture (LTTM) or deep eutectic solvent (DES) useful as a lubricating oil base stock and lubricating oil including a eutectic mixture of at least a first component and at least a second component. The at least first component comprises a hydrogen bond acceptor and the at least second component comprises a hydrogen bond donor. The eutectic mixture includes an equilibrium phase between the at least first component and the at least second component. The equilibrium phase does not exhibit physical characteristics of the at least first component in an unmixed state and the at least second component in an unmixed state. The at least first component and the at least second component form an intermolecular interaction between each other sufficient to prevent crystallization of the at least first component and the at least second component in the eutectic mixture. The eutectic mixture is a liquid at 20 C.

A low transition temperature mixture (LTTM) or deep eutectic solvent (DES) useful as a lubricating oil base stock and lubricating oil including a eutectic mixture of at least a first component and at least a second component. The at least first component comprises a hydrogen bond acceptor and the at least second component comprises a hydrogen bond donor. The eutectic mixture includes an equilibrium phase between the at least first component and the at least second component. The equilibrium phase does not exhibit physical characteristics of the at least first component in an unmixed state and the at least second component in an unmixed state. The at least first component and the at least second component form an intermolecular interaction between each other sufficient to prevent crystallization of the at least first component and the at least second component in the eutectic mixture. The eutectic mixture is a liquid at 20 C.

A fullerene derivative, used as a lubricant, includes, in a molecule: a fullerene backbone; and n pyrrolidine rings each being condensed to the fullerene backbone, each of the pyrrolidine rings including one aryl group including a group including m perfluoropolyether chains, m being an integer from 2 to 5 and n being an integer from 1 to 5.