Heat transfer fluids containing synergistic blends of corrosion inhibitor formulations

A heat transfer fluid comprising:

• greater than or equal to about 89 wt. % of a freezing point depressant that is selected from the group consisting of methanol, ethanol, propanol, butanol, furfurol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethoxylated furfuryl alcohol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, butylene glycol, glycerol, glycerol-1,2-dimethyl ether, glycerol-1,3-dimethyl ether, monoethylether of glycerol, sorbitol, 1,2,6-hexanetriol, trimethylopropane, methoxyethanol, and a combination thereof;
• a corrosion inhibitor formulation comprising:
• benzoic acid or an alkali metal salt thereof, wherein the salt of the optionally substituted benzoic acid comprises sodium benzoate, potassium benzoate, or a combination thereof;
• a first n-alkyl monocarboxylic acid selected from heptanoic acid, octanoic acid, an alkali metal salt thereof, and mixtures thereof;
• a second n-alkyl monocarboxylic acid selected from nonanoic acid, decanoic acid, or an alkali metal salt thereof, and mixtures thereof;
• an azole compound selected from the group consisting of benzotriazole, tolyltriazole, mercaptobenzothiazole, tetrahydro tolyltriazole, and a combination thereof;
• and
• a molybdate salt comprising sodium molybdate, potassium molybdate, or a combination thereof;
• wherein the heat transfer fluid has a pH between about 6.8 and about 10.0;
• wherein a ratio of weight percent of the first n-alkyl monocarboxylic acid or the salt thereof to weight percent of the second n-alkyl monocarboxylic acid or the salt thereof ranges from about 1:1.00 to about 1:1.75;
• and
• wherein a ratio of weight percent of the benzoic acid or the salt thereof to combined weight percent of the first n-alkyl monocarboxylic acid or the salt thereof and the second n-alkyl monocarboxylic acid or the salt thereof ranges from about 1:0.50 to about 1:2.00
• wherein the heat transfer fluid is free of silicates, borates, amines, branched carboxylates, dibasic-aliphatic carboxylates, dibasic-aromatic carboxylates, and acrylate based polymers.