Deactivation and Regeneration of Palladium Catalysts for Hydrogenation Debenzylation of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-Hexaazaisowurtzitane (HBIW)

Qunfeng Zhang; Mei Wang; Jiacheng Qian; Shuyuan Lou; Jianhong Jin; Bingcheng Li; Chunshan Lu; Feng Feng; Jinghui Lv; Qingtao Wang; Xiaonian Li

doi:10.3390/catal12121547

Catalysts (Dec 2022)

Deactivation and Regeneration of Palladium Catalysts for Hydrogenation Debenzylation of 2,4,6,8,10,12-Hexabenzyl-2,4,6,8,10,12-Hexaazaisowurtzitane (HBIW)

Qunfeng Zhang,
Mei Wang,
Jiacheng Qian,
Shuyuan Lou,
Jianhong Jin,
Bingcheng Li,
Chunshan Lu,
Feng Feng,
Jinghui Lv,
Qingtao Wang,
Xiaonian Li

Affiliations

Qunfeng Zhang: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Mei Wang: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Jiacheng Qian: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Shuyuan Lou: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Jianhong Jin: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Bingcheng Li: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Chunshan Lu: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Feng Feng: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Jinghui Lv: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Qingtao Wang: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China
Xiaonian Li: State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Institute of Industrial Catalysis of Zhejiang, University of Technology, Hangzhou 310014, China

DOI: https://doi.org/10.3390/catal12121547
Journal volume & issue: Vol. 12, no. 12
p. 1547

Abstract

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2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, also known as CL-20) is an important energetic compound. As one of the representatives of the third generation of energetic materials, it has an excellent performance, providing broad application prospects for the development of new weapons and equipment. The synthesis of CL-20 is usually obtained from 2,4,6,8,10,12-hexabenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (HBIW) through two catalytic hydrogenolysis and debenzylation reactions, followed by nitration. The most critical step is the hydrogenolysis debenzyl-acetylation process of HBIW because this process requires a large amount of expensive palladium-based catalyst, and the catalyst is completely deactivated after one use. In response to this problem, there is no suitable solution at present, resulting in the high cost of the entire synthesis process. Therefore, reducing the production cost of CL-20 by increasing the catalyst stability is one of the current research priorities. By using AAS, XRD, XPS, TEM, BET, TG and other characterization techniques, the reasons for catalyst deactivation were explored. Studies have shown that the main reason for catalyst deactivation is that a large number of blockages accumulate in the pores of the catalyst after the reaction, which greatly weakens the transfer of the reactant HBIW, intermediate substances, and product 2,6,8,12-tetraacetyl-4,10-dibenzyl-2,4,6,8,10,12-hexaazaisowurtzitane (TADBIW) in the catalyst pores, and the blockage may block the active site of the catalyst. A regeneration treatment method for catalyst deactivation was developed. This method uses chloroform and glacial acetic acid as reagents, which, when combined with stirring and ultrasonic operation, finally restores the activity of the Pd(OH)2/C catalyst. The BET and TG parameters of the regenerated catalyst indicate that catalyst textural and structural properties have greatly recovered, indicating that this treatment method can remove the blockages in the catalyst pores.

Published in Catalysts

ISSN: 2073-4344 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Chemical technology; Science: Chemistry
Website: https://www.mdpi.com/journal/catalysts

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