Reported in EPA TSCA Inventory.

The IUPAC name of (1,6-Hexanediylbis(nitrilobis(methyl-ene)))tetrakisphosphonic acid is [6-[bis(phosphonomethyl)amino]hexyl-(phosphonomethyl)amino] methylphosphonic acid. With the CAS registry number 23605-74-5 and EINECS 245-781-0, it is also named as Dequest 2051 deflocculant and sequestrant. The product's categories are Organics; Phosphonate Antiscalant. It is white powder which is slightly soluble in water. When heated to decomposition it emits toxic vapors of NO_x. Additionally, this chemical should be stored in the cool and dry place.

The other characteristics of this product can be summarized as: (1)ACD/LogP: -5.82; (2)# of Rule of 5 Violations: 2; (3)ACD/LogD (pH 5.5): -11.98; (4)ACD/LogD (pH 7.4): -13.82; (5)ACD/BCF (pH 5.5): 1; (6)ACD/BCF (pH 7.4): 1; (7)ACD/KOC (pH 5.5): 1; (8)ACD/KOC (pH 7.4): 1; (9)#H bond acceptors: 14; (10)#H bond donors: 8; (11)#Freely Rotating Bonds: 15; (12)Polar Surface Area: 187.84 Å²; (13)Index of Refraction: 1.586; (14)Molar Refractivity: 95.59 cm³; (15)Molar Volume: 284.7 cm³; (16)Surface Tension: 101.4 dyne/cm; (17)Enthalpy of Vaporization: 136.48 kJ/mol; (18)Vapour Pressure: 3.27E-33 mmHg at 25°C; (19)Rotatable Bond Count: 15; (20)Exact Mass: 492.05927; (21)MonoIsotopic Mass: 492.05927; (22)Topological Polar Surface Area: 237; (23)Heavy Atom Count: 28; (24)Complexity: 547.

Preparation of (1,6-Hexanediylbis(nitrilobis(methyl-ene)))tetrakisphosphonic acid: Adding 1mol anhydrous hexamethylenediamine, 8mol (144g) deionized water, 4mol formaldehyde into the reaction flask with sealed stirrer, reflux condenser and dropping funnel. Stirring and cooled below 30 °C. Then slowly dropping 4mol phosphorus trichloride and controlling the reaction temperature at 30 ~ 40 °C. After adding phosphorus trichloride, the temperature slowly rises to 110 °C. Finally, we can get the liquid product after backflow reaction.

Uses of (1,6-Hexanediylbis(nitrilobis(methyl-ene)))tetrakisphosphonic acid: It can inhibit the production of a variety of scale (such as calcium carbonate scale, calcium sulfate scale, barium sulfate scale and iron oxide scale, etc.), but it is mainly used to inhibit calcium sulfate and barium sulfate scale in water treatment.

People can use the following data to convert to the molecule structure. 
1. SMILES:O=P(O)(O)CN(CP(=O)(O)O)CCCCCCN(CP(=O)(O)O)CP(=O)(O)O
2. InChI:InChI=1/C10H28N2O12P4/c13-25(14,15)7-11(8-26(16,17)18)5-3-1-2-4-6-12(9-27(19,20)21)10-28(22,23)24/h1-10H2,(H2,13,14,15)(H2,16,17,18)(H2,19,20,21)(H2,22,23,24)
3. InChIKey:KIDJHPQACZGFTI-UHFFFAOYAI

The following are the toxicity data which has been tested.