An overview on CL-20 synthesis and key issues with the TAIW route, along with improvement strategies

High Energy Density Materials (HEDMs) refer to materials with extensive applications in the fields of rocketry, propellants, and explosives chemistry. CL-20 is not only stands as the most powerful explosive in contemporary use but also represents a clean and highly efficient oxidizer for future propellants in terms of combustion performance. Currently, most countries use TAIW as the nitration precursor to synthesize CL-20, but many challenges still need to be addressed. Therefore, this paper primarily focuses on the synthesis of TAIW and provides a detailed account of a series of issues encountered during its synthesis, such as high production costs, catalyst deactivation, and multiple side reactions. In response to these problems, numerous researchers have proposed improvement strategies. On one hand, catalyst modification, reaction condition optimization, and the search for the most suitable solvent combinations are explored to enhance reaction selectivity and yield while reducing byproduct formation. On the other hand, effective methods for dealing with deactivated catalysts are investigated to enable their reusability and cost reduction. These improvements provide valuable insights for the large-scale production and application of CL-20 and serve as useful references for the development of synthetic methods for other high-energy explosive compounds.