Lubricant composition and use as a lubricant additive of guanidinium-based ionic liquids

A method for reducing and/or limiting and/or preventing and/or delaying the formation of deposits or for reducing the deposits already present in the internal parts of a combustion engine comprising the application of a guanidinium-based ionic liquid or a lubricant composition comprising it

• wherein the guanidinium-based ionic liquid responds to formula (I):
• [CAT+][X−] (I)
• wherein
• [X−] represents one or more anionic species, [CAT+] is selected from cations of formula (II):
• wherein:
• R1, R2 are each independently selected from H, a C1-C30 linear or branched alkyl group, a C3-C8 cycloalkyl group, a C6-C12 aryl group, or a C7-C12 aralkyl group, optionally substituted by a functional group comprising an oxygen and/or a nitrogen atom,
• R3, R4, R5, R6 are each independently selected from a C1-C30 linear or branched alkyl group, a C3-C8 cycloalkyl group, a C6-C12 aryl group, or a C7-C12 aralkyl group, optionally substituted by a functional group comprising an oxygen and/or a nitrogen atom,
• or any two of (R3, R4) or (R5, R6) form together a methylene chain —(CH2)p-, with p is an integer from 2 to 5.

A lubricant composition comprising:

• from 30.0 to 94% of at least one base oil,
• from 0.05 to 15.0% of at least one guanidinium-based ionic liquid,
• at least one detergent selected from neutral and overbased detergents having a Total Base Number according to ASTM D2896 of from 20 to 450 mg KOH/g
• the percentages being defined by weight of component as compared to the total weight of the composition
• wherein the guanidinium-based ionic liquid responds to formula (I):
• [CAT+][X−] (I)
• wherein
• [X−] represents one or more anionic species, [CAT+] is selected from cations of formula (II):
• wherein:
• R1, R2 are each independently selected from H, a C1-C30 linear or branched alkyl group, a C3-C8 cycloalkyl group, a C6-C12 aryl group, or a C7-C12 aralkyl group, optionally substituted by a functional group comprising an oxygen and/or a nitrogen atom,
• R3, R4, R5, R6, are each independently selected from a C1-C30 linear or branched alkyl group, a C3-C8 cycloalkyl group, a C6-C12 aryl group, or a C7-C12 aralkyl group, optionally substituted by a functional group comprising an oxygen and/or a nitrogen atom,
• or any two of (R3, R4) or (R5, R6) form together a methylene chain —(CH2)p-, with p is an integer from 2 to 5.