TY - CHAP

T1 - Catalytic Aspects in the Synthesis of a Promising Energetic Material

AU - Simakova, Irina L.

AU - Parmon, Valentin N.

N1 - Publisher Copyright: © 2017, Springer International Publishing Switzerland.

PY - 2017

Y1 - 2017

N2 - Synthesis of a promising energetic material CL-20 requires the two-step catalytic re-functionalization of N-bonded benzyl groups (CH2-C6H5) of hexabenzylhexaazaisowurtzitane (HBIW) into acetyl (-CO-CH3) or formyl groups (-CHO) over Pd/C catalyst before its direct nitrolysis into final CL-20 product. Utilization of an expensive palladium-based catalyst deactivated fast during reaction contributes substantially to a high CL-20 cost being a significant hurdle limiting wide application of CL-20 in a propellant formulation. In this work a careful systematic study was performed to improve efficiency, resistance to deactivation, and life-time of Pd/C catalysts as well as to elucidate the optimal hydrodebenzylation reaction conditions. The catalyst activity decrease for Pd/C was found to be caused mainly by agglomeration of metal nanoparticles, Pd re-deposition on inaccessible inner areas of the carbon support, and blocking of the metallic palladium with by-products of intermediates destruction. Different ways to enhance Pd/C catalytic activity through an improvement of Pd dispersion and resistance of Pd particles to agglomeration and re-oxidation as well as through an increase of Pd accessibility for large HBIW molecules were proposed. The two-step HBIW debenzylation with a separately repeated use of the catalyst in each catalytic stage was considered as a promising way to increase catalyst productivity and to diminish CL-20 production costs.

AB - Synthesis of a promising energetic material CL-20 requires the two-step catalytic re-functionalization of N-bonded benzyl groups (CH2-C6H5) of hexabenzylhexaazaisowurtzitane (HBIW) into acetyl (-CO-CH3) or formyl groups (-CHO) over Pd/C catalyst before its direct nitrolysis into final CL-20 product. Utilization of an expensive palladium-based catalyst deactivated fast during reaction contributes substantially to a high CL-20 cost being a significant hurdle limiting wide application of CL-20 in a propellant formulation. In this work a careful systematic study was performed to improve efficiency, resistance to deactivation, and life-time of Pd/C catalysts as well as to elucidate the optimal hydrodebenzylation reaction conditions. The catalyst activity decrease for Pd/C was found to be caused mainly by agglomeration of metal nanoparticles, Pd re-deposition on inaccessible inner areas of the carbon support, and blocking of the metallic palladium with by-products of intermediates destruction. Different ways to enhance Pd/C catalytic activity through an improvement of Pd dispersion and resistance of Pd particles to agglomeration and re-oxidation as well as through an increase of Pd accessibility for large HBIW molecules were proposed. The two-step HBIW debenzylation with a separately repeated use of the catalyst in each catalytic stage was considered as a promising way to increase catalyst productivity and to diminish CL-20 production costs.

KW - SUPPORTED PALLADIUM CATALYSTS

KW - REDUCTIVE DEBENZYLATION

KW - PD/C CATALYSTS

KW - STEARIC-ACID

KW - KEY STEP

KW - CL-20

KW - HEXABENZYLHEXAAZAISOWURTZITANE

KW - HYDROGENATION

KW - DEACTIVATION

KW - CARBON

KW - Optimization

KW - Design

KW - Hexabenzylhexaazaisowurtzitane

KW - Pd/C catalyst

KW - Hydrodebenzylation

KW - Acylation

UR - http://www.scopus.com/inward/record.url?scp=85062365484&partnerID=8YFLogxK

U2 - 10.1007/978-3-319-27748-6_29

DO - 10.1007/978-3-319-27748-6_29

M3 - Chapter

SN - 978-3-319-27746-2

T3 - Springer Aerospace Technology

SP - 697

EP - 724

BT - Springer Aerospace Technology

A2 - DeLuca, LT

A2 - Shimada, T

A2 - Sinditskii, VP

A2 - Calabro, M

PB - SPRINGER-VERLAG BERLIN

T2 - 12th International Workshop on Combustion and Propulsion - New Energetic Materials for Space Exploration

Y2 - 9 June 2014 through 10 June 2014

ER -