Multi-ring antioxidants with antiwear properties
View Patent ↗Described are multi-ring antioxidant products comprising at least one sulfur-bridged aromatic hydrocarbon compound substituted on at least one of its aromatic rings by at least one sterically hindered 3,5-dihydrocarbyl-4-hydroxybenzyl moiety. Such products have the formula: R—S n —R[—S—R] m wherein each R is, independently, an aromatic hydrocarbon group having 6-12 carbon atoms, wherein m is 0-20, wherein n is 1-6 when m is 0, and when n is 1, m is 1-20; and wherein at least one of R, R 1 , and R 2 is substituted by at least one such sterically hindered moiety. The preparation of such products and their use as antioxidants in compositions normally susceptible to oxidative degradation in oxygen or air, e.g., liquid fuel and lubricants, are also described.
1. A composition which comprises organic material normally susceptible to oxidative degradation in the presence of air or oxygen with which material has been blended a multi-ring antioxidant product in an amount sufficient to inhibit such oxidative degradation, wherein the organic material is an oil of lubricating viscosity or a liquid fuel composition, and wherein the multi-ring antioxidant has the formula
wherein:
R and R′ are selected from hydrogen atoms, hydrocarbyl, alkoxy, aryloxy, alkylthio, halo, amino, alkyl amino, or aryl amino substituent groups which do not interfere with the reaction which forms the compounds of this invention;
p is 0-4; and
q is, independently, 1-4.
2. A composition as in claim 1 in which the antioxidant is in the liquid state at one or more temperatures below 100° C.
3. A composition as in claim 1 wherein said organic material is an oil of lubricating viscosity.
4. A composition as in claim 1 wherein said organic material is a liquid fuel composition.
5. A composition as in claim 1 wherein R and R′ are hydrogen atoms.
6. The composition of claim 1 , wherein p is 0-2.
7. The composition of claim 6 , wherein p is 1.
8. The composition of claim 1 , wherein q is 1-2.
9. The composition of claim 8 , wherein q is 1.
10. The composition of claim 1 , wherein R and R′ are each hydrocarbyl.
11. The composition of claim 1 , wherein the multi-ring antioxidant has the formula of: