Trilon® D Liquid - the Performance Chemicals division - BASF.com

Technical InformationTI/EVD 1116 eJanuary 2007 Page 1 of 8Supersedes edition dated August 1997® = Registered trademark ofBASF AktiengesellschaftTrilon ® D LiquidOrganic chelating agent used to control the concentration of metalions in aqueous systems

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidContentsPropertiesChemical nature Page 3Chemical and physical data Page 3Complex formation Page 4Chemical stability Page 6Corrosion Page 6Applications Page 7SafetyStorage Page 8Labelling Page 8Note Page 8

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidPropertiesChemical natureThe active ingredient contained in Trilon D Liquid is hydroxyethylenediaminetriacetic acid (HEDTA or HEDTA-H 3) or its salts.Hydroxyethylenediaminetriacetic acid, C 10H 15N 2O 7, is an aminocarboxylicacid with six functional groups.HOCH 2CH 2CCOONaNCH 2CH 2NNaOOCCH 2H 2CH 2COONaTrilo D LiquidAqueous solution of the trisodium salt of hydroxyethylenediaminetriaceticacid (HEDTA-Na 3)CAS No. 139-89-9Chemical and physical dataUnitTrilon D LiquidPhysical form (visual) Clear, yellow liquidMolar mass (DIN 32625) g/mol 344Concentration (BASF method)*expressed as trisodium salt (HEDTA-Na 3) % approx. 40expressed as free acid (HEDTA-H 3) % approx. 32Density (DIN 51757, 20 °C, U-tube densitometer) g/cm 3 approx. 1.26pH (DIN 19268, 23 °C, 1% in water) approx. 11.5Hazen colour (DIN EN 1557) max. 250Volatile NH 3(BASF method) ppm max. 100Calcium binding capacity (BASF method, pH 11) mg CaCO 3/g t. q. approx. 125Water content (EN 13268) % approx. 56Viscosity (DIN 53018, 23 °C) mPa · s approx. 30Pour point (ISO 3016) °C < – 20Solubility in water (BASF method)25 °C g/l Miscible in all proportions80 °C g/lThe above information is correct at the time of going to press. It does not necessarily form part of the product specification.A detailed product specification is available from your local BASF representative.* Determined by potentiometric titration against iron(III)chloride.

TI/EVD 1116 e January 2007 Page of 8 Trilon D Liquid300Viscosity mPa·s250Trilon D Liquid200150100500-10 0 10 20 30Temperature (°C)Viscosity as a function of temperatureComplex formationThe most important property of Trilon D Liquid is its ability to form watersolublecomplexes with polyvalent ions (eg. calcium, magnesium, lead, copper, zinc, cadmium, mercury, manganese, iron, aluminium) over a widepH range from 2 to 13.5. HEDTA usually forms 1 : 1 complexes, i. e. 1 mol ofHEDTA chelates binds to 1 mol of metal ions. The metal ion is completelyenclosed by the ligand. These complexes remain stable, especially in alkalimedia and even at temperatures of up to 100 °C. [MeZ (m-n)- ]K = ––––––––––––– [Me n+ ] [Z m- ]From the law of mass action, the equation for the stability constant K for1 : 1 complexes can be written as follows:where[MeZ (m-n)- ][Me n+ ]is the concentration of the chelate that is formedis the concentration of free, positively charged metalions[Z m- ] is the concentration of the ligand anion, in this caseHEDTAKis the stability constant for the chelate.

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidLogarithmic stability constants (log K) for complexes of HEDTA and selectedmetal ionsMetal ionlog KFe 3+ 19.8Cu 2+ 17.5Ni 2+ 17.1Zn 2+ 14.6Fe 2+ 12.2Mn 2+ 10.8Ca 2+ 8.2Mg 2+ 7.0HEDTA-H 3is a tribasic acid that dissociates in three steps. The acid dissociation constants pK aare as follows.HEDTA-H 3 pK a 1 2.6HEDTA-H- 2 pK a 2 5.3HEDTA-H 2- pK a 3 9.7In aqueous solutions, HEDTA competes for metal ions with other anionssuch as hydroxide, sulphate, sulphide, carbonate and oxalate that formsparingly soluble metal salts. The formation of chelates reduces the concentrationof free metal ions [Me n+ ] to such an extent that the solubility productsof many sparingly soluble metal salts are no longer exceeded. The result isthat the salts no longer precipitate or may even redissolve.The high stability of these complexes prevents the metal ions from participatingin typical chemical reactions. For instance, manganese, iron and copper are no longer able to catalyse the decomposition of peroxide bleach.Conditional stability constants [log K cond] take into account the stability constant K as well as the acid base dissociation equilibria.16log K cond14121086420Ca 2+Cu 2+Fe 3+Mg 2+Mn 2+0 2 4 6 8 10 12 14pHConditional stability constants for selected HEDTA chelates

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidThe table below shows the pH ranges in which HEDTA forms stable complexes.1 g of Trilon D Liquid is able to sequester the following amounts of metalions, independently of the temperature.mg Metal ion pH rangeapprox. 47 Ca 2+ 8.5 – 11.0approx. 28 Mg 2+ 10.0 – 12.0approx. 74 Cu 2+ 3.0 – 11.0approx. 65 Fe 3+ 2.0 – 10.0Chemical stabilityTrilon D Liquid is chemically very stable.The Trilon D Liquid exhibit a higher stability than other organic chelatingagents such as citric acid, tartaric acid and gluconates – especially at elevated temperatures.Whereas inorganic sequestring agents (eg. phosphates) may hydrolyse athigh temperatures, Trilon D Liquid is stable – even when heated to 200 °Cunder pressure.CorrosionThe Trilon D Liquid is resistant to strong acids and bases. It is gradually broken down by chromic acid, potassium permanganate and other strongoxidizing agents. Stability in the presence of hydrogen peroxide, percarbonateand perborate is sufficient for joint application. Nevertheless, we do notrecommend combining Trilon D Liquid and peroxides in liquid formulations.Sodium hypochlorite and other substances that release chlorine have ahighly detrimental effect on the performance of Trilon D Liquid. Alkaline earthand heavy metal complexes are broken down.Trilon D Liquid stabilizes polyvalent metal ions, which means that it canincrease the rate at which metals dissolve. Nevertheless, with the exceptionof aluminium, an oxidizing agent such as air always has to be present forcorrosion to take place. Unalloyed steel is prone to corrosion in media thatcontain air, but corrosion can be reduced substantially if the pH is in thealkaline range and can be eliminated almost completely if oxygen and otheroxidizing agents are excluded. With the exception of aluminium, metals thatare cleaned in the slightly alkaline range, which is the optimum pH range forTrilon D Liquid, are much less prone to corrosion than if they are cleanedwith acids. The only type of corrosion that has been observed with Trilon D Liquid isuniform corrosion: pitting or stress cracking have not been observed inmedia with a low chloride content. One of the advantages of Trilon D Liquidis that it can be supplied with a very low chloride content (< 20 mg/kg).The following information on materials is of a very general nature, becausecorrosion depends on many different factors such as exposure to air, galvanic corrosion caused by the presence of different materials and by theflow patterns of liquids. The compatibility of Trilon D Liquid with differentmaterials needs to be tested in each individual case.Austenitic stainless steels such as AISI/SAE 316 Ti and AISI/SAE 321 arevery effective for vessels that are used to store and transport Trilon D Liquid.Ferritic carbon steel such as ASTM A201 Grade B (European Material No. P265GH) is fairly resistant to Trilon D Liquid. A rate of corrosion of < 0.01 mm/a has been measured at 54 °C.Aluminium and aluminium alloys such as AL 7075 T6 (European Material No. 3.3465) are not resistant to Trilon D Liquid, because it is alkaline andaluminium is quickly corroded by strong bases.

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidApplicationsTrilon D Liquid forms more stable complexes with iron(III) ions than otherorganic complexing agents in the strongly alkaline pH range. It forms complexeswith Fe 3+ in the 2 – 10 pH range, but other complexing agents aregenerally restricted to the acidic and neutral pH range.Stoichiometric amounts of Trilon D Liquid are required to complex metalions. Solutions are clear after they have been treated with chelating agents,and they do not need to be filtered or decanted.Trilon D Liquid can be used to dissolve precipitated metal salts and hydroxides.Traces of free metal ions are always present in equilibrium with salts,even if these salts are very sparingly soluble. If these free ions are chelated,the equilibrium is gradually displaced in favour of the soluble chelates.The rate at which deposits dissolve depends on their crystal structure andage, and on the temperature. Increasing the temperature can help toincrease the rate at which precipitated solids dissolve.Old, dried-on scale has to be treated with Trilon D Liquid over a longer period, and we would recommend applying 1 g/l more than the stoichiometric amount in this case.Solutions of Trilon D Liquid are much less susceptible to precipitation by acids and alkalis than solutions of other complexing agents such as EDTA.Trilon D Liquid is approx. 6 % soluble in 30 % caustic soda, whereas EDTA-Na 4is only 0.5 % soluble in 30 % caustic soda. Trilon D Liquid’s higher stabilityallows it to be used in a wider range of formulations than the Trilon ® A typesor Trilon B types.SafetyWe know of no ill effects that could have resulted from using the Trilon D Liquid for the purpose for which it is intended and from processing itin accordance with current practice.According to the experience we have gained over many years and otherinformation at our disposal, the Trilon D Liquid does not exert any harmfuleffects on health, provided that it is used properly, due attention is given tothe precautions necessary for handling chemicals, and the information andadvice given in our Safety Data Sheets are observed.

TI/EVD 1116 e January 2007 Page of 8 Trilon D LiquidStorageTrilon D Liquid should not be stored at temperatures below 0 °C, becausethis can cause it to precipitate. It can be reconstituted by heating it briefly to40 – 50 °C and stirring.Trilon D Liquid is easily capable of being pumped at temperatures down to – 10 °C.Trilon D Liquid has a shelf life of one year in its tightly sealed original packaging.We would recommend storing the Trilon D Liquid in tanks made from AISI 316 Ti or AISI 321 stainless steel.LabellingPlease refer to the latest Safety Data Sheets for detailed, up-to-date information on classification, labelling and product safety.NoteThe data contained in this publication are based on our current knowledge and experience. In view of the many factors that may affect processing and application of our product, these data do not relieve processors from carrying out their own investigations and tests; neither do these data imply any guarantee of certain properties, nor the suitability of the product for a specific purpose. Any descriptions, drawings, photographs, data, pro-portions, weights etc. given herein may change without prior information and do not constitute the agreed contractual quality of the product. It is the responsibility of the recipient of our products to ensure that any proprietary rights and existing laws and legislation are observed.January 2007BASF AktiengesellschaftPerformance Chemicals forDetergents and Formulators67056 Ludwigshafen, Germanywww.basf.com/detergents-formulators