Sulfur-containing carboxylic acid derivatives to reduce deposit forming tendencies and improve antioxidancy of aviation turbine oils

A turbo oil composition exhibiting enhanced resistance to deposition and improved oxidative stability, said turbo oil formulation comprising a major portion of a synthetic ester based base stock and a minor portion of a sulfur containing carboxylic acid (SCCA) derivative, wherein the SCCA derivative is represented by the structural formula:

• ##STR8## wherein R.sub.1 is C.sub.2 -C.sub.12 alkylene with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, arylene, C.sub.1 to C.sub.8 alkyl substituted arylene, R' is hydrogen or C.sub.1 to C.sub.8 alkyl, R.sub.2 is the group ##STR9## wherein R.sub.1 and R.sub.3 are the same or different and are C.sub.2 -C.sub.12 alkylene with the --COOR group separated from S by a linear alkylene group containing at least 2 carbons, arylene, C.sub.1 to C.sub.8 alkyl substituted arylene, and R' and R" are different and are hydrogen, and C.sub.1 -C.sub.8 alkyl.

A turbo oil composition exhibiting enhanced resistance to deposition and improved oxidative stability, said turbo oil formulation comprising a major portion of a synthetic ester based base stock and a minor portion of a sulfur containing carboxylic acid (SCCA) derivative, wherein the SCCA derivative is represented by the structural formula:

• ##STR10## wherein R.sub.1 is C.sub.2 -C.sub.4 alkylene with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, arylene, R' is hydrogen or C.sub.1 to C.sub.8 alkyl, R.sub.2 is the group ##STR11## wherein R.sub.1 and R.sub.3 are the same or different and are C.sub.2 -C.sub.4 alkylene with the --COOR' and COOR" groups separated from S by a linear alkylene group containing at least 2 carbons, arylene and R" is hydrogen.

A method for enhancing the resistance to deposition and improve the oxidation stability of a synthetic ester based turbo oil by adding to said turbo oil in an amount in the range 100 to 2000 ppm a sulfur containing carboxylic acid (SCCA) derivative, wherein the SCCA derivative is represented by the structural formula:

• ##STR12## wherein R.sub.1 is C.sub.2 -C.sub.12 linear alkylene, with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, R' is hydrogen or C.sub.1 to C.sub.8 alkyl, R.sub.2 is hydrogen, or the group ##STR13## and wherein when R.sub.2 is ##STR14## R.sub.1 and R.sub.3 are the same or different and are C.sub.2 -C.sub.12 linear alkylene, with the --COOR' and --COOR" groups separated from S by a linear alkylene group containing at least 2 carbons, and R' and R" are the same or different and are hydrogen and C.sub.1 -C.sub.8 alkyl.

A turbo oil composition exhibiting enhanced resistance to deposition and improve the oxidation stability, said turbo oil formulation comprising a major amount of a synthetic ester based base stock and a minor portion of a sulfur containing carboxylic acid (SCCA) derivative, wherein the SCCA derivative is represented by the structural formula:

• ##STR15## wherein R.sub.1 is C.sub.2 -C.sub.4 alkylene with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, R' is hydrogen or C.sub.1 to C.sub.8 alkyl, R.sub.2 is hydrogen, or the group ##STR16## and wherein when R.sub.2 is ##STR17## R.sub.1 and R.sub.3 are the same or different and are C.sub.2 -C.sub.4 alkylene with the --COOR' and --COOR" groups separated from S by a linear alkylene group containing at least 2 carbons and R" is hydrogen.

A method for enhancing the resistance to deposition and improve the oxidation stability of a synthetic ester based turbo oil by adding to said turbo oil a sulfur containing carboxylic acid (SCCA) derivative in an amount in the range 100 to 2000 ppm, wherein the SCCA derivative is represented by the structural formula:

• ##STR20## wherein R.sub.1 is C.sub.2 -C.sub.12 alkylene with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, arylene, C.sub.1 to C.sub.8 alkyl substituted arylene, R' is C.sub.1 to C.sub.8 alkyl and R.sub.2 is hydrogen.

A method for enhancing the resistance to deposition and improve the oxidation stability of a synthetic ester based turbo oil by adding to said turbo oil a sulfur containing carboxylic acid (SCCA) derivative in an amount in the range 100 to 2000 ppm, wherein the SCCA derivative is represented by the structural formula:

• ##STR21## wherein R.sub.1 is C.sub.2 -C.sub.12 alkylene with the --COOR' group separated from S by a linear alkylene group containing at least 2 carbons, arylene, C.sub.1 to C.sub.8 alkyl substituted arylene, R' is hydrogen or C.sub.1 to C.sub.8 alkyl, R.sub.2 is the group ##STR22## wherein R.sub.1 and R.sub.3 are the same or different and are C.sub.2 -C.sub.12 alkylene with the --COOR' and --COOR" groups separated from S by a linear alkylene group containing at least 2 carbons, arylene, C.sub.1 to C.sub.8 alkyl substituted arylene, and R' and R" are the same or different and are hydrogen and C.sub.1 -C.sub.8 alkyl.