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Hydroxyphosphonoacetic acid , also known as ethanoic acid, is an organic acid with the formula CH3COOH. Hydroxyphosphonoacetic acid is an organic substance that gives vinegar its sour taste and pungent odor. There is 4-5% acetic acid in vinegar.
CAS NUMBER : 23783-26-8
SYNONYM :
C2H5O7P; 2-hydroxy-2-phosphonooxyacetic acid; 1649AB;AKOS006279076; 2-Hydroxyphosphonoacetic acid (Hydroxyphosphonoacetic acid); Z6074; 783H268; Hydroxyphosphonoacetic acid
The product is considered being a mild steel corrosion inhibitor and is mainly used in the water treatment industry. Hydroxyphosphonoacetic acid shows superior performance in all organic formulations compared to commonly used Phosphonates. In certain formulations Hydroxyphosphonoacetic acid can replace Molybdate or its derivatives. Esters of acetic acid are mostly used as solvents for inks, paints and coatings. Esters include n-butyl acetate, ethyl acetate, isobutyl acetate and propyl acetate. They are typically produced by the reaction catalyzed from acetic acid and the corresponding alcohol. H3C-COOH + HO-R → H3C-CO-O-R + H2O, (R = a general alkyl group) Also, most acetate esters are derived from acetaldehyde by the Tishchenko reaction. They are also used as a solvent in nitrocellulose, ether acetates, acrylic lacquers, varnish removers and wood stains. Its use in vinegar production is not so important. One of the most important areas of use is its use in industry as a solvent.
A coordination-induced film-forming method was developed to construct 2-hydroxyphosphonoacetic acid (Hydroxyphosphonoacetic acid)-Zn2+ complex conversion layer (Hydroxyphosphonoacetic acid-Zn2+ layer for short) on cold-rolled steel (CRS) substrate. Moreover, the incorporation of Mo component into the Hydroxyphosphonoacetic acid-Zn2+ layer can significantly improve the uniformity and anticorrosion properties. The results showed that Mo-incorporated Hydroxyphosphonoacetic acid-Zn2+ layer displayed the best anticorrosion performance when the molar ratio of Hydroxyphosphonoacetic acid/Zn2+ was 1:1, the film-forming time was 10 min, and the concentration of molybdate was 0.1 wt%. In addition, energy dispersive spectroscopic (EDS) and X-ray photoelectron spectroscopic (XPS) results demonstrated that the Mo-incorporated Hydroxyphosphonoacetic acid-Zn2+ layer was mainly composed of ZnO and Hydroxyphosphonoacetic acid-Zn2+ complex and also confirmed that Mo-O-P bonds occurred between molybdate anion and Hydroxyphosphonoacetic acid molecule.
A coordination-induced film-forming method was developed to construct Hydroxyphosphonoacetic acid-Zn2+ layer and Mo-incorporated Hydroxyphosphonoacetic acid-Zn2+ layer with better anticorrosion performance on cold-rolled steel (CRS) substrate. A composition and method of inhibiting corrosion, white rust, and scale formation on components in a water system. The composition preferably comprises an amino-acid based polymer (most preferably a potyaspartic acid or a salt thereof), Hydroxyphosphonoacetic acid and a second phosphonic acid (preferably a phosphonocarboxylic acid), and does not require the use of regulated metals. The composition is effective even in the presence of biocides. A preferred method of inhibiting white rust comprises adding an amino-acid based polymer or Hydroxyphosphonoacetic acid or both to the water system. A preferred method of inhibiting corrosion, white rust, and scale formation comprises adding an amino-acid based polymer, Hydroxyphosphonoacetic acid and a phosphonocarboxylic acid to the water system. Preferably the active concentrations are at least 3 ppm each of the amino-acid based polymer and Hydroxyphosphonoacetic acid when added to a volume of water in the water system.
2-Hydroxyphosphonocarboxylic Acid is chemically stable, hard to be hydrolyzed, hard to be destroyed by acid or alkali, safety in use, no toxicity, no pollution. 2-Hydroxyphosphonocarboxylic Acid can improve zinc solubility. Its corrosion inhibition ability is 5-8 times better than that of HEDP and EDTMP. When built with low molecular polymers, its corrosion inhibition effect is even better. 2-Hydroxyphosphonocarboxylic Acid is mainly used as cathode corrosion inhibitor in oilfield refill water system in fields such as steel & iron, petrochemcal, power plant and medical industries. When built with zinc salt, the effect is even better. Normally In 250kg net Plastic Drum, IBC drum can also be used as required. Storage for one year in room shady and dry place.
The inhibiting behavior of K4P2O7, C2H5O6P and their mixture on Q235 steel corroding in the simulated stratum water has been investigated by using electrochemical noise (EN) and electrochemical impedance spectroscopy (EIS) techniques. The results show that the physical adsorption of KPP onto Q235 surface at 60 C is somewhat faster than the chemisorption of Hydroxyphosphonoacetic acid. In the re-plotted energy distribution plot, the difference of the region where the EN energy is mostly accumulated may be adopted to distinguish the chemisorption and physical adsorption of inhibitors. Finally, the variation tendency of the charge transfer resistance obtained by EIS technique is just opposite to that of fractal dimension obtained by EN technique, which may hint that the initial corrosion processes of metals can be in-situ monitored by using EN technique expediently.
Infection with the human stomach pathogen Helicobacter pylori can lead to chronic gastritis, peptic ulcer and stomach cancer. All H. pylori strains express the surface-localized protein Hydroxyphosphonoacetic acid, which is a promising candidate for a vaccine against H. pylori infection. To study the physiological significance of Hydroxyphosphonoacetic acid, a mutation of the Hydroxyphosphonoacetic acid gene was introduced into a mouse adapted H. pylori strain. To confirm that the disruption of the Hydroxyphosphonoacetic acid gene did not cause any polar effects in downstream genes or was associated with a second region mutation, the protein expression patterns of the mutant and wild-type strains were characterized by two different proteomic approaches.
Two-dimensional differential in-gel electrophoresis analysis of whole cell extracts and subcellular fractionation combined with nano-liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry for outer membrane protein profile revealed only minor differences in protein profile between mutant and wild type strains. Therefore, the mutant strain was tested for its ability to colonize in a well established mouse model. Inoculation with the wild-type strain resulted in mice that were heavily infected with H. pylori, while the Hydroxyphosphonoacetic acid mutant strain was not able to induce colonization. Therefore, by combining proteomic analysis and in vivo studies, we concluded that Hydroxyphosphonoacetic acid is essential for H. pylori colonization in mice.
H. pylori adhesin A (Hydroxyphosphonoacetic acid) is a surface-found lipoprotein (7, 14, 20) originally identified as sialic acid-binding adhesin, but supporting evidence is still lacking. Hydroxyphosphonoacetic acid is recognized by antibodies obtained from individuals infected with H. pylori (23, 39), and the expression of the Hydroxyphosphonoacetic acid protein has previously been found to be highly conserved among H. pylori isolates . Moreover, genomic studies do not show any significant sequence homology of Hydroxyphosphonoacetic acid with other known proteins. Taken together, this makes Hydroxyphosphonoacetic acid a putative candidate as a vaccine antigen against H. pylori infection.
In this study, we generated a Hydroxyphosphonoacetic acid mutant in H. pylori Sydney strain 1 (SS1) adapted to mouse to examine the role of Hydroxyphosphonoacetic acid in colonization. Due to co-transcription, engineered gene mutations have polar effects, i.e. the potential to inhibit the expression of downstream genes in an operon. In addition, has been shown that knockout of one gene can affect other genes in an unpredictable way . Therefore, when examining a mutant, proteomic analysis provides a convenient method for tracking changes in protein expression without prior knowledge of what these changes might be.
The first aim of this study was to examine the overall protein profile including protein expression of genes downstream of Hydroxyphosphonoacetic acid of the mouse-adapted SS1 strain and its isogenic Hydroxyphosphonoacetic acid mutant. This was achieved by a proteomic approach where whole cell extracts of bacteria were compared with DIGE analysis. In addition, subcellular fractionation and one-dimensional sodium dodecyl sulfate (SDS) -polyacrylamide gel electrophoresis (PAGE) analysis were performed using nano-LC Fourier transform (FT) ion cyclotron resonance (ICR) (FT-ICR) MS and tandem MS (MS / MS) SS1. Analyzes to compare OMP profiles of wild-type and mutant strains. To determine whether Hydroxyphosphonoacetic acid is necessary for survival in the host, mice were infected with the H.pylori SS1 or Hydroxyphosphonoacetic acid mutant strain and their colonization levels
The Hydroxyphosphonoacetic acid mutant was first generated in the H. pylori strain CCUG 17874 by a two-step amplification that resulted in a 450 bp deletion of the Hydroxyphosphonoacetic acid gene (gently P.Doig et al., Astrazeneca Research Center, Boston, MA) with a 1.4 kb. Insertion of the kanamycin cassette. The mutation was transferred from H. pylori CCUG 17874 to the mouse adapted SS1 strain by natural transformation. Five kanamycin resistant transformants were analyzed by PCR with two Hydroxyphosphonoacetic acid-specific primers (forward primer, 5′-GGCGTAGAAATGGAAGCG-3 ′; reverse primer, 5′CCCAAGCTTCATCAGCCCTTAAATACACG-3 ′) to confirm insertion of the kanamycin cassette (21). The Hydroxyphosphonoacetic acid gene results in a larger PCR product than that of the wild type SS1 strain. One of the transformants with correct insertion was further characterized by SDS-PAGE and immunoblotting with Hydroxyphosphonoacetic acid-specific monoclonal antibody HP30-1: 1: 6. This strain, SS1 (Hydroxyphosphonoacetic acid), was negative in the immunoblot.
IUPAC NAME :
hexasodium (R)-carboxy(phosphono)methanolate; Hydroxyphosphonoacetic acid; (S) carboxy(phosphono)methanolate;Hydroxyphosphonoacetic acid trisodium salt; trisodium;2-hydroxy-2-phosphonatoacetate
TRADE NAME :
2-hydroxy-2-phosphonoacetic acid; Acetic acid, 2-hydroxy-2-phosphono-; Hydroxyphosphono-acetic acid
OTHER NAME :
015-159-00-1; 115469-15-3; 115469-15-3; 153733-51-8; 153733-51-8; 23783-26-8; 783H268
The mouse adapted H. pylori strains SS1 (CagA + VacA + Ley) (19) and SS1 (ΔHydroxyphosphonoacetic acid) were used in all experiments and stored at -70 ° C as stock cultures. For preparation of antigens from SS1 and SS1 (Hydroxyphosphonoacetic acid), bacteria were grown to confluence for 3 days on Colombia-Iso agar plates under microaerophilic conditions (10% CO2, 6% O2 and 84% N2). SS1 (Hydroxyphosphonoacetic acid) was cultured in the same way as SS1 throughout the experiment, except for cultures supplemented with 25 μg / ml blood amycin.
Process for conditioning metal surfaces to inhibit their corrosion and/or to inhibit scale deposition thereon by treating said surfaces:(A) prior to contact with a corrosive or scaling environment, with 2-hydroxy-phosphonoacetic acid or a metal salt thereof and optionally with a metal ion component (b) as hereinafter defined(B) during contact with an aqueous system capable of corroding said metal surfaces or depositing scale thereon, with a combination of:(a) 2-hydroxy-phosphonacetic acid or a water-soluble salt thereof; and(b) a metal ion which enhances, synergistically, the metal conditioning effected, individually, by 2-hydroxy-phosphonoacetic acid and the metal ion.
The present invention relates to a process for conditioning metal surfaces to inhibit corrosion of the metal surfaces and/or deposition of scale thereon. In GB No. 2 112 370 A, we have described and claimed a method of treating an aqueous system to inhibit corrosion of metals, especially ferrous metals, in contact therewith and/or to inhibit scale deposition from the aqueous system, comprising adding to the aqueous system from 0.1 to 50000 ppm of 2-hydroxy-phosphonoacetic acid having the formula I: ##STR1## or a water-soluble salt thereof. Suitable salts listed in GB No. 2 112 370 A are water-soluble salts or partial salts of e.g. an alkali metal, an alkaline earth metal, ammonia or a 1-20C alkylamine optionally substituted with one to six hydroxyl groups. Specific salts listed are lithium, sodium, potassium, calcium, strontium, magnesium, ammonia, methylamine, ethylamine, n-propylamine, trimethylamine, triethylamine, n-butylamine, n-hexylamine, octylamine, ethanolamine and triethanolamine.
Said salts are merely listed as alternatives to the free acid form of 2-hydroxy-phosphonoacetic acid: there is no suggestion that any synergistic effects could be obtained by employing specific metal ions in combination with 2-hydroxy-phosphonoacetic acid. Nor is there any suggestion in GB No. 2 112 370 A that Hydroxyphosphonoacetic acid could be employed to condition metal surfaces against corrosion prior to exposure to a corrosive or scaling environment. We have now found that metal surfaces may be conditioned to inhibit their corrosion and/or to inhibit scale deposition thereon if the metal surfaces are treated, prior to contact with a corrosive/scaling system, with 2-hydroxy-phosphonoacetic acid or a water-soluble salt thereof and optionally a metal ion component.
Moreover, we have also found, surprisingly, that synergistic effects are obtained when metal surfaces liable to corrosion and/or scale deposition are treated during contact with an aqueous corrosive scaling system, with a combination of 2-hydroxy-phosphonoacetic acid and certain metal ions. Accordingly, the present invention provides a process for conditioning metal surfaces, especially ferrous, or copper (or their alloys) surfaces, to inhibit their corrosion and/or to inhibit scale deposition thereon by: (A) treating said surfaces, prior to contact with a corrosive or scaling environment, with 2-hydroxy-phosphonoacetic acid or a water-soluble salt thereof and optionally a metal ion component (b) as hereinafter defined; or (B) treating said surfaces, during contact with an aqueous system capable of corroding metal surface or depositing scale thereon, with a combination of: (a) 2-hydroxy-phosphonoacetic acid or a water-soluble salt thereof and (b) a metal ion which enhances, synergistically, the metal conditioning effected, individually, by 2-hydroxy-phosphonoacetic acid and the metal ion.
Treatments (A) and (B) can advantageously be applied by cathodically polarising the metal surface to be treated e.g. by any of the conventional impressed current techniques, see e.g. Chapter 11 of "Corrosion", L. L. Schneir, Newnes-Butterworth, 1976. With respect to the treatments effected under heading (A), the metal surface to be treated may be contacted with e.g. an aqueous solution of 2-hydroxy-phosphonoacetic acid (or a water-soluble salt thereof) optionally in combination with a metal ion component especially a metal ion (b) which imparts synergistic corrosion inhibiting and/or scale inhibiting effects in combination with 2-hydroxy-phosphonoacetic acid. Some typical applications of treatments (A) with the preferred application of impressed current techniques include temporary protection of metal surfaces to be exposed to corrosive atmospheres e.g. ambient atmospheres; pre-treatment of metal surfaces to be subsequently painted; co-treatment in order to seal a phosphated metal surface; and formulating a paint containing Hydroxyphosphonoacetic acid (or a salt thereof) and optionally metal ion component (b) and then applying this paint on to the metal surface to be conditioned by e.g. spraying, brushing, dipping or cathodically electro-depositing.
In each of these typical applications of treatments of type A, the metal surface e.g. a phosphated mild steel surface may be immersed in a solution of 2-hydroxy-phosphonoacetic acid (or a water-soluble salt thereof), optionally containing a metal ion component (b), as hereinbefore defined, or said solution may be painted or sprayed on to the said phosphated metal surface. With respect to sealing of phosphated metal surfaces, Hydroxyphosphonoacetic acid is common practice to phosphate the surface of metal articles to form a bonding or keying layer for protective or decorative paint finishes on the metal articles and to minimise subsequent corrosion under the finish. The term phosphating is applied to the treatment of the metal surface in solutions which form a coating consisting mainly of metal phosphates. Such coatings, while forming a good key for the paint finish, are generally not entirely satisfactory in inhibiting subsequent corrosion due to the porosity of the phosphate coating.
Hydroxyphosphonoacetic acid is therefore customary to improve said corrosion inhibition by sealing the phosphate coating, traditionally by immersion in an aqueous chromate solution. However, the use of chromate solutions presents toxicity and effluent problems and therefore, there is a need to find new sealing techniques which avoid the disadvantages associated with chromate sealing. We have found that the application of a type A conditioning according to the invention provides effective phosphate sealing, optionally in combination with cathodising the phosphated metal surface, and avoids the problems associated with conventional chromate treatments.
In relation to the electropainting technique, the initial coating of paint or polymer applied to the surface of metal articles, either directly on to the metal surface or after phosphating, is commonly an electropaint. Electropaints are coating compositions, emulsified or solubilised in water. These compositions can be caused to be deposited on to a metal surface by polarising said metal surface, either anodically or cathodically relative to another electrode, according to the type of paint used. When a cathodically applied electropaint is deposited, the corrosion resistance of the coated metal may be enhanced by simultaneously conditioning the metal surface, or sealing the phosphate coating, according to the type A embodiment of the present invention, by incorporating Hydroxyphosphonoacetic acid (or a water-soluble salt thereof) optionally in combination with a synergistic metal ion (b), into the electropaint composition.
In treatment according to the invention under heading A or B, the metal ion component may be used as an independent metal salt or as the pre-formed salt of the compound of formula I, or a combination of the two. Suitable metal ion components (b) include, e.g. cobalt, ferrous, barium, calcium, zinc, chromium, nickel, strontium, manganous, cadmium, ceric and magnesium ions. Some of these metal ions e.g. calcium and barium per se do not impart any corrosion inhibition. While some of these metal ion components (b) overlap with metal salts listed in GB No. 2 112 370 A others such as cobalt, ferrous and barium ions, which provide very effective synergistic combinations with the compound of formula I, while generally embraced, are not specifically disclosed in GB No. 2 112 370 A.
Moreover, GB No. 2 112 370 A does not suggest that the use of the compound of formula I, in the form of a water-soluble salt, could lead to enhanced results over and above the results to be obtained using the free acidic form of the compound of formula I. 2-Hydroxy-phosphonoacetic acid is a known compound having been described in U.S. Pat. No. 3,032,500 and, more recently in European Patent Application No. 0027199. Hydroxyphosphonoacetic acid can be prepared by known methods e.g. by reacting orthophosphorous acid, a salt or a solution thereof, or phosphorous trichloride (or PCl.sub.3 /water mixtures) with glyoxylic acid, a salt or a solution thereof. The ratio of 2-hydroxy-phosphonoacetic acid (or water-soluble salt thereof) to metal ion component (b), used in the corrosion- and/or scale-inhibiting combinations employed in the conditioning processes of invention, may vary within wide limits e.g. from 100:1 to 1:100, more preferably from 10:1 to 1:10 parts by weight.
In practice, the amount of the combination of 2-hydroxy-phosphonoacetic acid and metal ion which is used to treat the metal surface e.g. by adding the combination to the aqueous system in contact with the metal surface will vary depending upon the protective function which the combination is required to perform. For corrosion-inhibiting protective treatments, optionally in combination with scale inhibiting treatments, the amount of said combination added to the aqueous system is conveniently within the range of from 0.1 to 50,000 ppm (or 0.00001 to 5% by weight) preferably from 1 to 500 ppm (or 0.0001 to 0.05% by weight) based on aqueous system. For solely anti-scale purposes, the amount of said combination used is conveniently from 1 to 200 ppm, preferably 1 to 30 ppm, based on the aqueous system.
With respect to aqueous systems from which a metal surface may be conditioned according to the present invention, of particular interest with respect to combined corrosion inhibition and anti-scale treatments are cooling water systems, steam generating systems, sea-water evaporators, hydrostatic cookers, gas scrubbing systems, closed circuit heating systems, aqueous-based refrigeration systems and oil field applications; for corrosion inhibition treatments alone, aqueous systems of particular interest include aqueous machining fluid formulations (e.g. for use in boring, milling, reaming, broaching, drawing, spinning, turning, cutting, sawing, grinding, and thread-cutting operations or in non-cutting shaping in drawing or rolling operations), aqueous scouring systems, engine coolants including aqueous glycol antifreeze systems, water/glycol hydraulic fluids; and aqueous based polymer surface-coating systems.
In the particular case of the inhibition of scale and corrosion in oil field applications, special problems are presented which are not encountered in more conventional water treatment applications. Thus, formation water, associated with oil-bearing strata, often contains barium and strontium as well as ions such as calcium, magnesium, carbonate and bicarbonate ions which are more commonly found in surface waters and sea water. Therefore, in situations in which surface or sea water becomes mixed with formation water, severe scaling can occur due to the precipitation of barium sulphate, strontium sulphate, calcium carbonate and mixtures thereof. This type of scaling occurs e.g. during cooling/depressurisation of recovered crude oil/water emulsions in the rock formation in the well base and in the well bore when water is pumped into the formation to "squeeze" a well. This type of scale formation can be effectively inhibited by the conditioning technique according to the present invention.
In addition to inhibiting the deposition of conventional scale on to metal surfaces, the conditioning process of the present invention is also useful in inhibiting deposition of calcium--or magnesium silicate scales. The synergistic inhibitor combination may be used alone or in conjunction with other compounds known to be useful in the treatment of aqueous systems. Wholly aqueous systems from which the process of the present invention may be applied, including cooling water systems, air-conditioning systems, steam-generating systems, sea-water evaporator systems, hydrostatic cookers, and closed circuit heating or refrigerant systems, further corrosion inhibitors may be used such as, for example, water soluble zinc salts; phosphates; polyphosphates; phosphonic acids and their salts, for example, acetodiphosphonic acid, nitrilotris methylene phosphonic acid and methylamine dimethylene phosphonic acid; other phosphonocarboxylic acids and their salts, for example, those described in German Offenlegungsschrift No. 2632774, 2-phosphonobutane-1,2,4-tricarboxylic acid and those disclosed in GB No. 1572406; chromates for example, sodium chromate; nitrates, for example sodium nitrate; nitrites e.g. sodium nitrite; molybdates e.g. sodium molybdate; silicates e.g. sodium silicate; benzotriazole, 5,5-methylene-bis-benzotriazole or copper deactivating benzotriazole or tolutriazole derivatives; N-acyl sarcosines; N-acylimino diacetic acids; ethanolamines; fatty amines; and polycarboxylic acids, for example, polymaleic acid and polyacrylic acid, as well as their respective alkali metal salts, copolymers of maleic anhydride, copolymers of acrylic acid, and substituted derivatives of polymaleic and polyacrylic acids and their copolymers.
Moreover, in such completely aqeous systems, the synergistic inhibitor combination may be used in conjunction with further dispersing and/or threshold agents, e.g. polymerised acrylic acid (or its salts), phosphino-polycarboxylic acids (as described and claimed in British Pat. No. 1458235), hydrolysed polyacrylonitrile, polymerised methacrylic acid and its salts, polyacrylamide and copolymers thereof from acrylic and methacrylic acids, lignin sulphonic acid and its salts, tannin, naphthalene sulphonic acid/formaldehyde condensation products, starch and its derivatives, cellulose, acrylic acid/lower alkyl hydroxyacrylate copolymers such as those described in U.S. Pat. No. 4,029,577, sulphonated styrene/maleic anhydride copolymers, styrene/maleic anhydride copolymers and sulphonated styrene homopolymers such as those described in the U.S. Pat. No. 4,374,733 and combinations thereof. Specific threshold agents, such as for example, 2-phosphonobutane-1,2,4-tricarboxylic acid, acetodiphosphonic acid, hydrolysed polymaleic anhydride and its salts, alkyl phosphonic acids, 1-aminoalkyl-1,1-diphosphonic acids and their salts, and alkali metal polyphosphates, may also be used.
Precipitating agents such as alkali metal orthophosphates, carbonates; oxygen scavengers such as alkali metal sulphites and hydrazines; sequestering agents such as nitrilotriacetic acid and its salts; antifoaming agents such as silicones e.g. polydimethylsiloxanes, distearylsebacamide, distearyl adipamide and related products derived from ethylene oxide and/or propylene oxide condensations, in addition to fatty alcohols, such as capryl alcohols and their ethylene oxide condensates; and biocides e.g. amines, quaternary ammonium compounds, chlorophenols, sulphur-containing compounds such as sulphones, methylene bis thiocyanates and carbamates, isothiazolones, brominated propionamides, triazines, phosphonium compounds, chlorine and chlorine-release agents and organometallic compounds such as tributyl tin oxide, may be used.
f the metal to be conditioned by the method of the invention is treated from a system which is not completely aqueous e.g. an aqueous machining fluid formulation, Hydroxyphosphonoacetic acid may be e.g. a water dilutable cutting or grinding fluid. The aqueous machining fluid formulations of the invention may be e.g. metal working formulations. By "metal working" we mean "reaming, broaching, drawing, spinning, cutting, grinding, boring, milling, turning, sawing, non-cutting shaping or rolling". Examples of water-dilutable cutting or grinding fluids into which the corrosion inhibiting combination may be incorporated include: (a) Aqueous concentrates of one or more corrosion inhibitors, and optionally one or more anti-wear additives, used at dilutions of 1:50 to 1:100, which are usually employed as grinding fluids; (b) Polyglycols containing biocides, corrosion inhibitors and anti-wear additives which are used at dilutions of 1:20 to 1:40 for cutting operations and 1:60 to 1:80 for grinding; (c) Semi-synthetic cutting fluids similar to (b) but containing in addition 10 to 25% oil with sufficient emulsifier to render the water diluted product translucent; (d) An emulsifiable mineral oil concentrate containing, for example, emulsifiers, corrosion inhibitors, extreme pressure/anti-wear additives, biocides, antifoaming agents, coupling agents etc; they are generally diluted from 1:10 to 1:50 with water to a white opaque emulsion; (e) A product similar to (d) containing less oil and more emulsifier which on dilution to the range 1:50 to 1:100 gives a translucent emulsion for cutting or grinding operations.
For those partly-aqueous systems in which the aqueous system component is an aqueous machining fluid formulation the synergistic inhibitor combination may be used singly, or in admixture with other additives e.g. known further corrosion inhibitors and/or extreme-pressure additives. Examples of other corrosion inhibitors which may be used in these aqueous systems, in addition to the inhibitor combination used according to the invention include the following groups: (a) Organic acids, their esters or ammonium, amine, alkanolamine and metal salts, for example, benzoic acid, p-tert-butyl benzoic acid, disodium sebacate, triethanolamine laurate, iso-nonanoic acid, triethanolamine salt of p-toluene sulphonamido caproic acid, sodium N-lauroyl sarcosinate or nonyl phenoxy acetic acid; (b) Nitrogen-containing materials such as the following types: fatty acid alkanolamides; imidazolines, for example, 1-hydroxy-ethyl-2-oleyl-imidazolines; oxazolines; triazoles, for example, benzotriazoles; triethanolamines; fatty amines; and inorganic salts, for example, sodium nitrate. (c) Phosphorous containing materials such as the following types: amine phosphates, phosphonic acids or inorganic salts, for example, sodium dihydrogen phosphate or zinc phosphate; (d) Sulphur containing compounds such as the following types: sodium, calcium or barium petroleum sulphonates, or heterocyclics, for example, sodium mercaptobenzothiazole. Nitrogen containing materials, particularly triethanolamine, are preferred.
Examples of extreme pressure additives which may be present in the systems treated according to the present invention include sulphur and/or phosphorous and/or halogen containing materials, for instance, sulphurised sperm oil, sulphurised fats, tritolyl phosphate, chlorinated paraffins or ethoxylated phosphate esters. When triethanolamine is present in the aqueous systems treated according to the present invention, Hydroxyphosphonoacetic acid is preferably present in an amount such that the ratio of synergistic inhibitor combination to triethanolamine is from 2:1 to 1:20. The partly-aqueous systems from which the process of the present invention may be applied may also be aqueous surface-coating compositions e.g. emulsion paints and aqueous powder coatings for matallic substrates.
The aqueous surface-coating composition may be e.g. a paint such as a styrene-acrylic copolymer emulsion paint, a resin, latex, or other aqueous based polymer surface-coating systems, used to coat a metal substrate. The inhibitor combination according to the present invention may be used to prevent flash rusting of the metal substrate during application of the surface coating and to prevent subsequent corrosion during use of the coated metal. In aqueous surface-coating compositions treated by the method of the invention the inhibitor combination may be used singly, or in admixture with other additives e.g. known corrosion inhibitors, biocides, emulsifiers and/or pigments. (A) 16.3 parts (0.11 mole) 50% aqueous glyoxylic acid and 8.2 parts (0.1 mole) orthophosphorous acid are heated together with stirring at 98.degree.-100.degree. C. for 24 hours to give 24.5 parts of 60% aqueous Hydroxyphosphonoacetic acid. (B) 150 parts of a 60% aqueous solution of Hydroxyphosphonoacetic acid obtained according to Example 1A is evaporated under reduced pressure (20 millibars) to give 104 parts of a viscous brown oil. This oil is induced to crystallise. The crude crystalline mass is then triturated with acetone to remove impurities. The resulting buff colored crystalline Hydroxyphosphonoacetic acid is removed by filtration, washed with acetone, and dried.
The crude crystalline Hydroxyphosphonoacetic acid so obtained is then recrystallised from water to give pure 2-hydroxyphosphonocetic acid as white crystals m.p. 165.degree.-167.5.degree. C. sup.31 P-NMR: .delta.=-14 ppm (relative to external H.sub.3 PO.sub.4): .sup.1 H-NMR: P-CH .delta.=4.24 ppm. J.sub.P-CH =18 Hz. IR: COOH: 1745 cm.sup.-1 ; P=0: 1200 cm.sup.-1. Corrosion inhibitor activity of the active inhibitor combination is demonstrated in the following way: Mild steel coupons, 5 cms..times.2.5 cms. are scrubbed with pumice, immersed for one minute in hydrochloric acid and then rinsed, dried and weighed. The desired proportion of additive combination is dissolved in 200 ml of deionised water. The metal ions are added as their chlorides and all test solutions are adjusted to pH 7 with sodium hydroxide. A steel coupon prepared as above is suspended in the solution, and the whole is stored in a closed bottle in a thermostat at 40.degree. C.
During the storage period, air is passed into the solution at 500 ml/minute, the passage of the air being screened from the steel coupon; any water losses by evaporation are replaced with deionized water. After 48 hours, the steel coupons are removed, scrubbed without pumice, immersed for one minute in hydrochloric acid inhibited with 1% by weight of hexamine and then rinsed, dried and reweighed. A certain loss in weight will have occurred. The results obtained in a series of tests using 100 ppm each of Hydroxyphosphonoacetic acid and various metal ions are set out in Table 1, in which m,d,d, denotes milligrams weight loss/sq. decimeter/day:
