Process for the stabilization of mercaptobenzothiazole in a lubricating oil composition

Claim 2

The use as a solvent for an amine salt of a substituted or unsubstituted mercaptobenzothiazole prepared by reacting, in the absence of an oxidizing agent, at least one mercaptobenzothiazole represented by the structural formula: wherein each R independently represents hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl; with at least one amine represented by the formula: wherein R 1 and R 2 independently represent hydrogen or about C l to C 20 alkyl, and R 3 represents alkyl or alkenyl having from about 6 to about 25 carbon atoms; and wherein the molar ratio at which said amine and mercaptobenzothiazole are reacted is from about 1.1:1 to about 0.7:1; of a compound of the formula wherein n represents a number of from 1 to 3, and each R8 independently is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl.

Claim 3

The use according to Claim 1 wherein the mercaptobenzothiazole is 2-mercaptobenzothiazole; the amine is a tertiary alkyl primary amine wherein in said formula II, R 1 and R 2 are hydrogen, and R 3 represents a tertiary alkyl group represented by the formula: wherein R 4 and R 5 independently represent C l to C 4 alkyl and R 6 represents Cg to C 19 alkyl.

Claim 4

The use according to Claim 1 or claim 2 wherein the amine used in the reaction is represented by the formula: wherein n' is a number which can vary from 1 to 5, and each R 7 independently represent hydrogen or methyl

Claim 5

The use according to any of the preceding Claims wherein the ratio of amine to mercaptobenzothiazole is not greater than 0.9:1.

Claim 6

The use according to any of the preceding claims of an amount of solvent sufficient to achieve a molar ratio of mercaptobenzothiazole in said salt to solvent of from 1:3 to 1:5.

Claim 7

The use according to any of the preceding claims of dihexyl phthalate.

Claim 8

A solution of a substituted or unsubstituted mercaptobenzothiazole prepared by reacting, in the absence of an oxidizing agent, at least one mercaptobenzothiazole represented by the structural formula: wherein each R independently represents hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl; with at least one amine represented by the structural formula: wherein R 1 and R 2 independently represent hydrogen or about C l to C 20 alkyl, and R 3 represents alkyl or alkenyl having from about 6 to about 25 carbon atoms; and wherein the molar ratio at which said amine and mercaptobenzothiazole are reacted is from about 1.1:2 to about 0.7:1; in a solvent of the structural formula: wherein n represents a number of from 1 to 3, and each R8 independently is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl.

Claim 9

A solution of a substituted or unsubstituted mercaptobenzothiazole prepared by reacting, in the absence of an oxidizing agent, at least one mercaptobenzothiazole represented by the structural formula: wherein each R independently represents hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl; with at least one amine represented by the structural formula: wherein R 1 and R 2 independently represent hydrogen or about C l to C 20 alkyl, and R 3 represents alkyl or alkenyl having from about 6 to about 25 carbon atoms; and wherein the molar ratio at which said amine and mercaptobenzothiazole are reacted is from about 1.1:2 to about 0.7:1; in a solvent of the structural formula: wherein n represents a number of from 1 to 3, and each R8 independently is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl.

Claim 10

The solution according to Claim 7 wherein the mercaptobenzothiazole is 2-mercaptobenzothiazole; the amine is a tertiary alkyl primary amine wherein in said formula I I, R 1 and R 2 are hydrogen, and R 3 represents a tertiary alkyl group represented by the formula: wherein R 4 and R 5 independently represent C 1 to C 4 alkyl and R 6 represents Cg to C 19 alkyl.

Claim 11

A solution according to claim 7 or claim 8 wherein the amine salt is admixed with solvent in an amount sufficient to achieve a molar ratio of mercaptobenzothiazole in said salt to solvent of from about 1:3 to about 1:5.

Claim 12

A solution according to any of claims 7 to 9 wherein the solvent is dihexyl phthalate.

Claim 13

A lubricating oil composition comprising a major amount of mineral oil of lubricating viscosity having added thereto a minor amount of a solution of at least one substituted or unsubstituted mercaptobenzothiazole amine salt dissolved in at least one solvent represented by the structural formula: wherein n represents a number of from 1 to 3 and each Rg independently is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl; wherein said amine salt has been prepared by reacting, in the absence of an oxidizing agent, at least one mercaptobenzothiazole represented by the structure formula: wherein each R independently represents hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl; with at least one amine represented by the structural formula: wherein R 1 and R 2 independently represent hydrogen or about C l to C 20 alkyl, and R 3 represent alkyl or alkenyl having from about 6 to about 25 carbon atoms; and wherein the molar ratio at which said amine and mercaptobenzothiazole are reacted is from about 1.1:1 to about 0.7:1.

Claim 14

A lubricating oil composition comprising a major amount of mineral oil of lubricating viscosity having added thereto a minor amount of a solution of at least one substituted or unsubstituted mercaptobenzothiazole amine salt dissolved in at least one solvent represented by the structural formula: wherein n represents a number of from 1 to 3 and each Rg independently is selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl and alkaryl; wherein said amine salt has been prepared by reacting, in the absence of an oxidizing agent, at least one mercaptobenzothiazole represented by the structure formula: wherein each R independently represents hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl; with at least one amine represented by the structural formula: wherein R 1 and R 2 independently represent hydrogen or about C l to C 20 alkyl, and R 3 represent alkyl or alkenyl having from about 6 to about 25 carbon atoms; and wherein the molar ratio at which said amine and mercaptobenzothiazole are reacted is from about 1.1:1 to about 0.7:1.

Claim 15

The lubricating oil composition of Claim 11 when used as an automatic transmission fluid.

Claim 16

The lubricating oil composition of Claim 11 or Claim 12 wherein the amine salt is derived from the reaction of 1-mercaptobenzothiazole and a tertiary alkyl primary amine wherein in said formula II, R 1 and R 2 are hydrogen, and R 3 represents a tertiary alkyl group having the formula: wherein R 4 and R 5 independently represent C 1 to C 4 alkyl and R 6 represents about Cg to C 19 alkyl.

Claim 17

The lubricating oil composition of any of Claims 11 to 13 wherein the molar ratio of amine to 2-mercaptobenzothiazole employed in forming the amine salt is not greater than 0.9:1.

Claim 18

The lubricating oil composition of Claim 8 wherein said solution is added to said lubricating oil at room temperature.