CDTA

CDTA
Name	CDTA
IUPAC name	trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (common)
Other names	trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid
Formula	C10H16N2O8
Molar mass	292.24 g·mol−1
Appearance	white crystalline powder
Solubility	soluble in water

CDTA

CDTA is an aminopolycarboxylic chelating agent used in coordination chemistry, analytical chemistry, and industrial water treatment. It functions similarly to other polyamino carboxylates by forming strong complexes with divalent and trivalent metal ions, and finds roles in complexometric titration, sequestering of trace metals, and as a ligand in studies of transition metal coordination. Researchers and practitioners across inorganic chemistry, environmental science, and process chemistry reference CDTA alongside well-known ligands and reagents.

Definition and Overview

CDTA is classified among polyaminocarboxylate ligands like ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and nitrilotriacetic acid. It consists of a cyclohexane backbone bearing two amino groups each substituted with acetic acid moieties, enabling hexadentate coordination to metal centers such as calcium, magnesium, iron(III), copper(II), and zinc(II). In analytical applications it is compared to indicators and titrants including EDTA titration protocols and chelating resins used in ion exchange. Industrial references situate CDTA within water softening, trace metal cleanup, and laboratory complexation alongside products from companies such as Sigma-Aldrich and Merck Group.

History and Development

The conceptual development of CDTA traces to mid-20th century advances in synthetic chelators following the discovery and commercialization of EDTA and related ligands. Synthetic methodologies evolved in academic laboratories studying coordination chemistry at institutions like University of Oxford, ETH Zurich, Massachusetts Institute of Technology, and University of California, Berkeley. Publications in journals associated with societies such as the American Chemical Society and Royal Society of Chemistry documented comparative stability constants versus classical ligands and prompted industrial adoption in sectors influenced by standards from bodies like ASTM International and regulatory frameworks from agencies such as the Environmental Protection Agency.

Applications and Uses

CDTA is used in analytical chemistry for complexometric titrations and as a masking agent in multicomponent assays performed in laboratories at institutions including National Institutes of Health, Johns Hopkins University, and Imperial College London. In industrial water treatment plants operated by utilities like Veolia and SUEZ, CDTA-based formulations sequester hardness ions and prevent scale formation on equipment produced by manufacturers such as Siemens and GE Water. In metal finishing and electroplating facilities tied to companies like BASF and 3M, CDTA helps control metal ion speciation. Research groups at centers such as Max Planck Society and Riken employ CDTA as a ligand in studies of coordination complex thermodynamics, kinetics, and as a competitor in chelation therapy research relative to agents used in clinical settings like deferoxamine and dimercaprol.

Chemical Properties and Structure

CDTA is a polyfunctional molecule with four carboxylate groups and two tertiary amine donors attached to a cyclohexane ring, enabling polydentate chelation and formation of stable five- and six-membered chelate rings with metal ions. Stability constants measured against metal ions such as Ca2+, Mg2+, Fe3+, and Cu2+ are reported alongside those for ligands like EDTA and DTPA in coordination chemistry literature. Stereochemistry (cis/trans isomers of the cyclohexanediamine core) affects denticity and complex geometry, influencing spectroscopic signatures recorded by techniques developed at facilities like Stanford Synchrotron Radiation Lightsource and interpreted using methods from nuclear magnetic resonance spectroscopy and x-ray crystallography common to research at institutions such as Brookhaven National Laboratory.

Synthesis and Production Methods

Synthesis routes for CDTA typically start from trans-1,2-diaminocyclohexane derived from hydrogenation of aniline derivatives or via resolution of racemic cyclohexanediamine produced by petrochemical feedstocks processed at plants operated by firms such as Dow Chemical Company. Alkylation of the amino groups with haloacetic acids or their esters followed by hydrolysis yields the tetraacetic acid functionality; reagents and catalysts employed in syntheses are described in protocols from academic groups at University of Cambridge and industrial R&D at organizations like DuPont. Process-scale production adapts batch or continuous flow techniques and adheres to standards promulgated by ISO and industrial safety frameworks of agencies such as Occupational Safety and Health Administration.

Safety, Toxicity, and Environmental Impact

Toxicological profiles for CDTA are compiled in material safety data sheets distributed by suppliers including Thermo Fisher Scientific and Fisher Scientific; these indicate handling precautions, dermal and ocular protection, and recommended exposure limits. Acute toxicity is generally moderate in mammalian models, with studies comparing metal-chelating ligand toxicities appearing in journals associated with World Health Organization guidelines. Environmental fate involves biodegradation, metal complex persistence, and potential effects on aquatic organisms monitored by programs under European Chemicals Agency and United States Geological Survey; risk assessments consider complex stability with trace metals such as lead, cadmium, and mercury and their bioavailability. Wastewater treatment approaches to remove CDTA and its metal complexes employ advanced oxidation processes, adsorption onto activated carbon used in facilities run by companies like Jacobi Carbons and Calgon Carbon, and engineered biodegradation strategies researched at universities such as Wageningen University.

Category:Chelating agents