New extractant N,N′-dimethyl-N,N′-dicyclohexyl-2,(2′-dodecyloxyethyl)-malonamide (DMDCDDEMA) for radiotoxic acidic waste remediation: Synthesis, extraction and supported liquid membrane transport studies

• New carrier extractant DMDCDDEMA was proposed and synthesized.
• SLM has been developed using DMDCDDEMA as the novel malonamide carrier.
• Extractive evaluation for radiotoxic actinides remediation has been carried out.
• The extractive and SLM systems have been evaluated quantitatively.
• Structural aspects have been discussed in comparison to earlier carrier analogues.

N,N′-dimethyl-N,N′-dicyclohexyl-2,(2′-dodecyloxyethyl)-malonamide (DMDCDDEMA) has been synthesized by a simpler route; with a better yield, than conventional pentaalkyl substituted diamide synthesis procedures. This route involves simple purification procedures like crystallization leading to desired molecule with high purity. The key step of 1-tosyloxy-3-oxa-pentadecane synthesis has been achieved by selective monoprotection of glycol with simpler chemical transformations. The synthesized product has been tested for radiotoxic metal ions (such as 241Am, 237Np, 239Pu, 233U) extraction and their transport behavior across a supported liquid membrane from nitric acid solutions. The effects of various experimental parameters on the possible radiotoxic waste remediation by this diamide have been evaluated quantitatively. The performance of DMDCDDEMA has been evaluated vis-à-vis other proposed carrier extractants for actinide partitioning under conditions of study. The study suggests that the relatively easier synthesis and its application in membrane based separations may help in scale up operations in radiotoxic waste remediation.

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