Catalytic decomposition of 1,3-diphenoxybenzene to monomeric cyclic compounds over palladium catalysts supported on acidic activated carbon aerogels

Authors: Hai Woong Park, Jeong Kwon Kim, Ung Gi Hong, Yoon Jae Lee, Jung Ho Choi, Yongju Bang, In Kyu Song

Abstract:
Activated carbon aerogel(ACA) was prepared by a chemical activation of carbon aerogel using phosphoric acid (H₃PO₄). Activated carbon aerogel bearing sulfonic acid (ACA-SO₃H), Cs_2.5H_0.5PW₁₂O₄₀-impregnated activated carbon aerogel (Cs_2.5H_0.5PW₁₂O₄₀/ACA), and Cs_2.5H_0.5PW₁₂O₄₀-impregnated activated carbon aerogel bearing sulfonic acid (Cs_2.5H_0.5PW₁₂O₄₀/ACA-SO3H) were prepared in order to provide acid sites to ACA. Palladium catalysts were then supported on ACA, ACA-SO₃H, Cs_2.5H_0.5PW₁₂O₄₀/ACA, and Cs_2.5H_0.5PW₁₂O₄₀/ACA-SO3H by an incipient wetness impregnation method. The prepared Pd/ACA, Pd/ACA-SO₃H, Pd/Cs_2.5H_0.5PW₁₂O₄₀/ACA, and Pd/Cs_2.5H_0.5PW₁₂O₄₀/ACA-SO3H catalysts were applied to the decomposition of 1,3-diphenoxybenzene. 1,3-Diphenoxybenzene was used as a trimeric lignin model compound for representing C-O bond in lignin. Cyclohexanol, benzene, and phenol were mainly produced by the decomposition of 1,3-diphenoxybenzene. 4-Phenoxyphenol was also produced as an intermediate by the decomposition of 1,3-diphenoxybenzene. Conversion of 1,3-diphenoxybenzene and total yield for main products (cyclohexanol, benzene, and phenol) increased with increasing acidity of the catalysts. Among the catalysts tested, Pd/Cs_2.5H_0.5PW₁₂O₄₀/ACA-SO3H with the largest acidity showed the highest conversion of 1,3-diphenoxybenzene and total yield for main products. Pd/Cs_2.5H_0.5PW₁₂O₄₀/ACA-SO₃H also served as a stable and reusable catalyst in the decomposition of 1,3-diphenoxybenzene.

Keywords:
Acidic activated carbon aerogel
Heteropolyacid
Pd catalyst
Lignin decomposition
1,3-Diphenoxybenzene

Published in: Applied catalysis A: General  (Volume 456, Pages 1-248, 10 April 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Catalytic decomposition of 1,3-diphenoxybenzene to monomeric cyclic compounds over palladium catalysts supported on acidic activated carbon aerogels

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