Sulfurized phenolic antioxidant composition method of preparing same and petroleum products containing same

An additive composition comprising:

• (a) from about 30% to about 95% by weight of an antioxidant composition comprising at least one thiophenol according to the formula:
• ##STR5## wherein R is an alkyl group;
• wherein R.sub.1 is selected from the group consisting of alkyl groups and hydrogen;
• wherein one of Z or Z.sub.1 is OH with the other being hydrogen;
• wherein one of Z.sub.2 or Z.sub.3 is OH with the other being hydrogen;
• wherein x is in the range of from 1 to 8;
• and wherein y is in the range of from 0 to 2 and has an average value of greater than 0 for the total antioxidant composition, said antioxidant composition being in a substantially liquid form, wherein said antioxidant composition is prepared by a process comprising
• (a) preparing a mixture of:
• (i) at least two different chlorine-free hindered phenols, wherein said phenols comprise a mixture of at least one dialkyl substituted phenol and at least one monoalkyl substituted phenol;
• (ii) a chlorine-free sulfur source;
• and
• (iii) at least one alkali metal hydroxide promoter;
• in 1-propanol;
• and
• (b) causing components (i), (ii) and (iii) to react for sufficient time and at sufficient temperature so as to form at least one chlorine-free sulfurized hindered phenol;
• and
• (c) the balance of said additive comprising at least one mineral or synthetic lubricant oil.

A method of producing a substantially liquid sulfurized hindered phenol, said method comprising the steps:

• (a) preparing a mixture of:
• (i) at least two different chlorine-free hindered phenols, wherein said phenols comprise a mixture of at least one dialkyl substituted phenol and at least one monoalkyl substituted phenol;
• (ii) a chlorine-free sulfur source;
• and
• (iii) at least one alkali metal hydroxide promoter;
• in 1-propanol;
• and
• (b) causing components (i), (ii) and (iii) to react for sufficient time and at sufficient temperature so as to form at least one chlorine-free sulfurized hindered phenol.

A method of reducing the oxidative environment in a petroleum composition selected from the group consisting of lubricating compositions and liquid organic fuels, said method comprising adding to said petroleum composition an effective amount of an antioxidant composition comprising at least one thiophenol according to the following formula:

• ##STR7## wherein R is an alkyl group;
• wherein R.sub.1 is selected from the group consisting of alkyl groups and hydrogen;
• wherein one of Z or Z.sub.1 is OH with the other being hydrogen;
• wherein one of Z.sub.2 or Z.sub.3 is OH with the other being hydrogen;
• wherein x is in the range of from 1 to 8;
• and y is in the range of from 0 to 2 and has an average value of greater than 0 for the total antioxidant composition and said antioxidant composition being in a substantially liquid form, and wherein said antioxidant is prepared by a process comprising
• (a) preparing a mixture of:
• (i) at least two different chlorine-free hindered phenols, wherein said phenols comprise a mixture of at least one dialkyl substituted phenol and at least one monoalkyl substituted phenol;
• (ii) a chlorine-free sulfur source;
• and
• (iii) at least one alkali metal hydroxide promoter;
• in 1-propanol;
• and
• (b) causing components (i), (ii) and (iii) to react for sufficient time and at sufficient temperature so as to form at least one chlorine-free sulfurized hindered phenol.

An improved antioxidant composition comprising at least one thiophenol of the formula:

• ##STR8## wherein R is an alkyl group;
• wherein R.sub.1 is selected from the group consisting of alkyl groups and hydrogen;
• wherein one of Z or Z.sub.1 is OH with the other being hydrogen;
• wherein one of Z.sub.2 or Z.sub.3 is OH with the other being hydrogen;
• wherein x is in the range of from 1 to 8;
• and wherein y is in the range of from 0 to 2 and has an average value of greater than 0 for the total antioxidant composition and said antioxidant composition being in a substantially liquid form, wherein said antioxidant is prepared by an improved process comprising
• (a) preparing a mixture of:
• (i) at least two different chlorine-free hindered phenols, wherein said phenols comprise a mixture of at least one dialkyl substituted phenol and at least one monoalkyl substituted phenol;
• (ii) a chlorine-free sulfur source;
• and
• (iii) at least one alkali metal hydroxide promoter;
• in an organic solvent;
• and
• (b) causing components (i), (ii) and (iii) to react for sufficient time and at sufficient temperature so as to form at least one chlorine-free sulfurized hindered phenol, wherein the improvement comprises using 1-propanol as the organic solvent.