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The Example of Succinic acid derivative degradable chelants, uses and compositions thereof
EXAMPLE 1
Preparation of Ethylenediaminedisuccinic Acid(cas:110-15-6) from Ethylenediamine and Maleic Acid and Preparation of the Ferric Chelate
A sample, 120.5 grams, of maleic acid (1.03 mole--Fisher reagent grade) is added to a beaker. Deionized water (120 grams) and 167 grams of 50 percent NaOH (2.08 mole--Fisher reagent grade) are added, and the fixture is stirred until dissolution is observed. The resulting solution is transferred to a 1 liter stainless steel autoclave vessel using about 40 mL of deionized water as rinse. A sample, 31.03 grams, of ethylenediamine (0.51 mole--commercially available from The Dow Chemical Co.) is slowly added to the stirred (magnetic stirrer) sodium maleate solution over a 10 minute period. Then a cap is placed on the autoclave which is equipped with a thermowell and thermometer connected to a Therm-O-Watch? temperature controller (commercially available from Instruments for Research & Industry (Cheltenham, Pa.)). Heat is supplied by a 30"×0.75" (76.2 cm×1.9 cm) section of heating tape wrapped around the autoclave which is then insulated with glass wool. Stirring is achieved by a magnetically-driven 1.5" (3.8 cm) Teflon? polytetrafluoroethylene coated stirrer bar. Temperature is maintained at 140° C. for about 9 hours, after which the mixture is allowed to cool to room temperature. The carbon NMR and proton NMR of the reaction mixture indicate essentially no remaining ethylenediamine and a very small amount of residual maleic acid. The reaction mixture is adjusted to a pH of approximately 2.0 with 36-37 percent hydrochloric acid (commercially available from Aldrich Chemical Co.). A powdery white precipitate develops which is filtered with Whatman #41 filter paper in a Buchner funnel. The precipitated solid is washed twice with 300 mL of deionized water. The resulting solids are dried overnight in a vacuum over at 60° C. Approximately 108 grams of product are obtained (74 percent yield of acid). The carbon NMR and proton NMR indicate essentially pure ethylenediaminedisuccinic acid(cas:110-15-6).
Preparation of Ferric-Ethylenediaminedisuccinic Acid(cas:110-15-6) and Stability at Various pH's
An approximately 0.01M iron (ferric)--ethylenediaminedisuccinic acid(cas:110-15-6) chelate solution is prepared by adding 1.63 grams of ethylenediaminedisuccinic acid(cas:110-15-6) and 200 mL of deionized water to a beaker. The slurry is stirred with a magnetic stirrer bar, and the pH is adjusted to 10.0 with 1.43 grams of 50 percent NaOH solution. A sample, 2.4 grams,. of iron nitrate solution (11.75 percent iron), commercially available from Shepherd Chemical Company, are added with stirring. The pH of the solution, which drops to 1.7, is adjusted to 6.6 with aqueous ammonia (29 percent concentration) solution (commercially available from J.T. Baker Chemical Co.). The iron chelate solution is then diluted in a volumetric flask to a final volume of 500 mL. Fifty gram aliquots of the solution are then placed in four 2 oz. (0.059 l) bottles and the pH of each is adjusted to 7.0, 8.05, 9.1 and 10.0 respectively with a few drops of an aqueous ammonia solution. One 50 gram aliquot is adjusted to a pH of 6.0 with a few drops of dilute hydrochloric acid, and one 50 gram aliquot is adjusted to a pH of 10.5 with a 10 percent solution of sodium carbonate (8.5 g). The sample that is pH 10.5 develops an iron hydroxide precipitate almost immediately. The sample at pH 10.0 begins to form iron hydroxide after about 4 hours. The samples that are pH 6.0, 7.0, 8.05, and 9.1 do not develop any noticeable iron hydroxide. The samples are allowed to stand for 6 days at which time the "overheads" (that is liquids not containing visible solids) from each of the samples are analyzed for soluble iron by inductively coupled plasma spectroscopy. Results are given in Table 1
EXAMPLE 2
Chelation of Copper with Polyamino Disuccinic Acids(cas:110-15-6)
Ethylenediamine disuccinic acid and diethylenetriamine disuccinic acid are titrated with standard 0.01M copper chloride solution. The titrations are performed using ammonium purpurate (indicator for complexometric titration commercially available from Aldrich Chemical Co., Inc. under the trade designation Murexide) at a pH of approximately 8 using sodium acetate as buffer. Both polyamino disuccinic acids complexed copper at a molar ratio of 1 mole of copper per mole of polyamino disuccinic acid.
EXAMPLE 3
Complexation of Copper in Alkaline Solutions
To be effective in an electroless copper plating bath, a chelating agent must maintain the copper is a soluble form in the pH range of about 10 to about 14. An especially preferred range is about 11 to 12.5. To determine the effectiveness of the polyamino disuccinic acids to prevent the precipitation of copper across this pH range a 0.05M copper chelate solution of ethylenediamine disuccinic acid is prepared from copper chloride, ethylenediamine disuccinic acid and sodium hydroxide. Approximately 70.0 gram portions are adjusted with sodium hydroxide solution to pH values of 10, 12, and 14. The ethylenediamine disuccinic acid is observed to maintain the copper in solution at these pH values preventing the precipitation of insoluble copper hydroxide. By comparison, a 0.05M copper solution prepared without the polyamino disuccinic acid ligand, used in the same manner at a pH of 10, 12 and 14 results in precipitation of insoluble copper hydroxide from the solutions almost immediately.
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