Amino acids as green neutralizing agent for acidic corrosion inhibitors

Abstract

With the present invention, sustainable systems for corrosion, inhibition in the processing of metals (in particular iron, aluminum and magnesium) are made available. These systems being in full accordance with the principles of green chemistry comprise an amino acid as neutralizing component for an acidic corrosion inhibitor, whereby the amino acid is used in deprotonated form. The resulting metalworking fluids may be water- or oil-based or semi synthetic formulations. The neutralization of acidic corrosion inhibitors with the claimed system comprising an amino acid consistently achieves convincing results and, together with acidic corrosion inhibitors from corresponding sources, completely renewable systems for corrosion inhibition are provided.

1 . Method of of neutralizing an acidic corrosion inhibitor in the formulation of a metalworking fluid, which comprises incorporating am amino acid as a neutralizing component in said metalworking fluid wherein the amino acid is used in deprotonated form as its salt with a base; preferably in form of its alkali metal- or earth alkali metal salts, which may be formed in situ in an equimolar mixture with NaOH, KGH, or LiOH, and wherein the amino acid is monomeric, in form of a dipeptide or wherein the amino acid is a derivative of a monomeric amino acid or of a dipeptide. 
     
     
         1 . The method of  claim 1 , wherein the amino acid represents the only neutralizing component and/or wherein the amino acid carries a primary amino-function. 
     
     
         3 . The method of  claim 1 , wherein the monomeric amino acid or both components of the dipeptide are proteinogenic amino carboxylic acids, analogues or derivatives thereof, or amines with another acid functionality. 
     
     
         4 . The method of  claim 1 , wherein
 a. the monomeric amino acid is glycine, methionine, cysteine, amino caproic acid (ACA), glutamic acid, or taurine, or the dipeptide is N-(L-α-aspartyl)-L-phenylalanine or its 1-methyl ester,   b. the acidic corrosion inhibitor is triazintriyltriiminotrihexanoic, arylsulfonamido carboxylic acid, sebacic acid, undecanoic acid, dodecanoic acid, azelaic acid, tall oil derived acids, sulfonates and/or phosphonic—and phosphoric acids, and for   c. the metal is iron, aluminum, magnesium, titanium, beryllium, zirconium or a corresponding alloy (such as Al 5083, Al 2074, or Mg AZ31).   
     
     
         5 . The method of  claim 1 , wherein the amino acid is present in an amount of one molar equivalent or more (relative to the number of acid functions of the acidic corrosion inhibitor), preferably in an amount of 1-3 molar equivalents, most preferably in an amount of 1.5 molar equivalents. 
     
     
         6 . The method of  claim 1  when used for limiting the leaching of alloy elements (such as Co, Cu, and Ni) from a corresponding alloy. 
     
     
         7 . Metalworking fluid comprising an acidic corrosion inhibitor and an amino acid, wherein the amino acid is monomeric, in form of a dipeptide or wherein the amino acid is a derivative of a monomeric amino acid or of a dipeptide, and wherein the amino acid is used in deprotonated form as its salt with a base. 
     
     
         8 . The metalworking fluid of  claim 7 , wherein the amino acid is glycine, methionine, cysteine, aminocaproic acid (ACA), glutamic acid, or taurine, or a salt thereof, preferably the sodium, potassium, or lithium salt. 
     
     
         9 . The metalworking fluid of  claim 7 , wherein the amino acid is present in an amount of one molar equivalent or more (relative to the number of acid functions of the acidic corrosion inhibitor. 
     
     
         10 . The metalworking fluid of  claim 7 , wherein the acidic corrosion inhibitor is a phosphonic acid derivative of a terpene or a fatty acid. 
     
     
         11 . The metalworking fluid of  7  which is water-based, oil-based, or in form of an emulsion. 
     
     
         12 . The metalworking fluid of  claim 7  further comprising a synthetic amine, such as 2-amino-2-methy Ipropanol 1 (AMP), 1-aminopropan-2-ol (MIPA) or triethanolamine (TEA). 
     
     
         13 . Method of processing of iron, aluminum, magnesium, titanium, beryllium, zirconium or a corresponding alloy (such as Al 5083, Al2024, or Mg, AZ31) which comprises using a metalworking fluid as claimed in  claim 7 . 
     
     
         14 . The method of  claim 3 , wherein said amine with another acid functionality contains a sulfonic acid group, a phosphonic acid group, or a phosphoric acid group. 
     
     
         15 . Metalworking fluid of  claim 7 , wherein said amino acid is used in form of its alkali metal- or earth alkali metal salts or in form of an equimolar mixture with NaOH, KOH, or LiOH. 
     
     
         16 . Metalworking fluid of  claim 15 , wherein said amino acid is used in the form of its sodium, potassium, or lithium salt. 
     
     
         17 . Metalworking fluid of  claim 9 , wherein the amino acid is present in an amount of of 1-3 molar equivalents, most preferably in an amount of 1.5 molar equivalents relative to the number of acid functions of the acidic corrosion inhibitor. 
     
     
         18 . The metalworking fluid of  claim 8 , wherein the amino acid is present in an amount of one molar equivalent or more (relative to the number of acid functions of the acidic corrosion inhibitor. 
     
     
         19 . Metalworking fluid of  claim 18 , wherein the amino acid is present in an amount of of 1-3 molar equivalents, most preferably in an amount of 1.5 molar equivalents relative to the number of acid functions of the acidic corrosion inhibitor. 
     
     
         20 . Method of_processing of iron, aluminum, magnesium, titanium, beryllium, zirconium or a corresponding alloy (such as Al 5083, Al2024, or Mg AZ31)_which comprises using a metalworking fluid as claimed in  claim 18 .