Catalyst-free and solvent-free oxidation of cycloalkanes (C5-C8) with molecular oxygen: Determination of autoxidation temperature and product distribution

doi:10.1016/j.cjche.2018.02.019

Abstract

Abstract: Autoxidation of cycloalkanes (C5-C8) with molecular oxygen under catalyst-free and solvent-free conditions was conducted systematically for the first time, focusing on the autoxidation temperature and product distribution. The autoxidation of cyclopentane, cyclohexane, cycloheptane and cyclooctane occurs at 120℃, 130℃, 120℃, and 105℃ respectively, with obvious oxidized products formation. At 140℃, 145℃, 130℃ and 125℃, acceptable yields of the oxidized products could be obtained for them, and the oxidized product distributions were investigated in detail. The autoxidation of cycloalkanes follows the pseudo-first-order kinetic model and the apparent activation energies (E_a) for the autoxidation of cyclopentane and cyclohexane are 159.76 kJ·mol^-1 and 86.75 kJ·mol^-1 respectively. This study can act as an important reference in screen of suitable reaction temperature and comparison of the performance of various catalysts in the catalytic oxidation of cycloalkanes in the attempt to enhance the oxidized product selectivity.

Key words: Cycloalkane, Oxidation, Autoxidation temperature, Product distribution

摘要： Autoxidation of cycloalkanes (C5-C8) with molecular oxygen under catalyst-free and solvent-free conditions was conducted systematically for the first time, focusing on the autoxidation temperature and product distribution. The autoxidation of cyclopentane, cyclohexane, cycloheptane and cyclooctane occurs at 120℃, 130℃, 120℃, and 105℃ respectively, with obvious oxidized products formation. At 140℃, 145℃, 130℃ and 125℃, acceptable yields of the oxidized products could be obtained for them, and the oxidized product distributions were investigated in detail. The autoxidation of cycloalkanes follows the pseudo-first-order kinetic model and the apparent activation energies (E_a) for the autoxidation of cyclopentane and cyclohexane are 159.76 kJ·mol^-1 and 86.75 kJ·mol^-1 respectively. This study can act as an important reference in screen of suitable reaction temperature and comparison of the performance of various catalysts in the catalytic oxidation of cycloalkanes in the attempt to enhance the oxidized product selectivity.

关键词: Cycloalkane, Oxidation, Autoxidation temperature, Product distribution

Haimin Shen, Yan Wang, Jinhui Deng, Long Zhang, Yuanbin She. Catalyst-free and solvent-free oxidation of cycloalkanes (C5-C8) with molecular oxygen: Determination of autoxidation temperature and product distribution[J]. Chin.J.Chem.Eng., 2018, 26(5): 1064-1070.

References

[1] Y. Hitomi, K. Arakawa, T. Funabiki, M. Kodera, An iron(Ⅲ)-monoamidate complex catalyst for selective hydroxylation of alkane C-H bonds with hydrogen peroxide, Angew. Chem. Int. Ed. Eng. 51(14) (2012) 3448-3452.

[2] S. Staudt, E. Burda, C. Giese, C.A. Muller, J. Marienhagen, U. Schwaneberg, W. Hummel, K. Drauz, H. Groger, Direct oxidation of cycloalkanes to cycloalkanones with oxygen in water, Angew. Chem. Int. Ed. Eng. 52(8) (2013) 2359-2363.

[3] J.H. Tong, L.L. Bo, X.D. Cai, H.Y. Wang, Q.P. Zhang, L.D. Su, Aerobic oxidation of cyclohexane effectively catalyzed by simply synthesized silica-supported cobalt ferrite magnetic nanocrystal, Ind. Eng. Chem. Res. 53(25) (2014) 10294-10300.

[4] P.F. Zhang, H.F. Lu, Y. Zhou, L. Zhang, Z.L. Wu, S.Z. Yang, H.L. Shi, Q.L. Zhu, Y.F. Chen, S. Dai, Mesoporous MnCeOx solid solutions for low temperature and selective oxidation of hydrocarbons, Nat. Commun. 6(2015) 8446, https://doi.org/10.1038/ncomms9446.

[5] A.P. Unnarkat, T. Sridhar, H.T. Wang, S. Mahajani, A.K. Suresh, Cobalt molybdenum oxide catalysts for selective oxidation of cyclohexane, AIChE J. 62(12) (2016) 4384-4402.

[6] D.N.J. Xiao, J. Oktawiec, P.J. Milner, J.R. Long, Pore environment effects on catalytic cyclohexane oxidation in expanded Fe-2(dobdc) analogues, J. Am. Chem. Soc. 138(43) (2016) 14371-14379.

[7] D. Mandal, S. Shaik, Interplay of tunneling, two-state reactivity, and Bell-Evans-Polanyi effects in C\ \H activation by nonheme Fe(IV)O oxidants, J. Am. Chem. Soc. 138(7) (2016) 2094-2097.

[8] G. Huang, W.L. Wang, X.X. Ning, Y. Liu, S.K. Zhao, Y.A. Guo, S.J. Wei, H. Zhou, Interesting green catalysis of cyclohexane oxidation over metal tetrakis(4-carboxyphenyl)porphyrins promoted by zinc sulfide, Ind. Eng. Chem. Res. 55(11) (2016) 2959-2969.

[9] Y. Shiraishi, S. Shiota, H. Hirakawa, S. Tanaka, S. Ichikawa, T. Hirai, Titanium dioxide/reduced graphene oxide hybrid photocatalysts for efficient and selective partial oxidation of cyclohexane, ACS Catal. 7(1) (2017) 293-300.

[10] A. Alshammari, A. Koeckritz, V.N. Kalevaru, A. Bagabas, A. Martin, Significant formation of adipic acid by direct oxidation of cyclohexane using supported nano-gold catalysts, ChemCatChem 4(9) (2012) 1330-1336.

[11] B. Sarkar, P. Prajapati, R. Tiwari, R. Tiwari, S. Ghosh, S.S. Acharyya, C. Pendem, R.K. Singha, L.N.S. Konathala, J. Kumar, T. Sasaki, R. Bal, Room temperature selective oxidation of cyclohexane over Cu-nanoclusters supported on nanocrystalline Cr₂O₃, Green Chem. 14(9) (2012) 2600-2606.

[12] A.R. Silva, T. Mourao, J. Rocha, Oxidation of cyclohexane by transition-metal complexes with biomimetic ligands, Catal. Today 203(2013) 81-86.

[13] Y.J. Xie, F.Y. Zhang, P.L. Liu, F. Hao, H.A. Luo, Zinc oxide supported trans-CoD(p-Cl)PPCltype Metalloporphyrins catalyst for cyclohexane oxidation to cyclohexanol and cyclohexanone with high yield, Ind. Eng. Chem. Res. 54(9) (2015) 2425-2430.

[14] Y. Ide, M. Iwata, Y. Yagenji, N. Tsunoji, M. Sohmiya, K. Komaguchi, T. Sano, Y. Sugahara, Fe oxide nanoparticles/Ti-modified mesoporous silica as a photo-catalyst for efficient and selective cyclohexane conversion with O₂ and solar light, J. Mater. Chem. A 4(41) (2016) 15829-15835.

[15] J. Jian, K.Y. You, Q. Luo, H.X. Gao, F.F. Zhao, P.L. Liu, Q.H. Ai, H.A. Luo, Supported Ni-Al-VPO/MCM-41 As efficient and stable catalysts for highly selective preparation of adipic acid from cyclohexane with NO₂, Ind. Eng. Chem. Res. 55(13) (2016) 3729-3735.

[16] M.Z. Wu, W.C. Zhan, Y.L. Guo, Y. Guo, Y.S. Wang, L. Wang, G.Z. Lu, An effective Mn-Co mixed oxide catalyst for the solvent-free selective oxidation of cyclohexane with molecular oxygen, Appl. Catal. A Gen. 523(2016) 97-106.

[17] M. Rezaei, A.N. Chermahini, H.A. Dabbagh, Green and selective oxidation of cyclohexane over vanadium pyrophosphate supported on mesoporous KIT-6, Chem. Eng. J. 314(2017) 515-525.

[18] S. Rana, S.B. Jonnalagadda, CuO/graphene oxide nanocomposite as highly active and durable catalyst for selective oxidation of cyclohexane, ChemistrySelect 2(7) (2017) 2277-2281.

[19] X.F. Song, J.M. Hao, Y.J. Bai, L.M. Han, G.F. Yan, X. Lian, J.S. Liu, Solvent-free oxidation of cyclohexane by oxygen over Al-Cu-Co alloys:influence of the phase structure and electrical conductivity on catalytic activity, New J. Chem. 41(10) (2017) 4031-4039.

[20] V.T. Wyatt, M. Yadav, N. Latona, C.K. Liu, Thermal, mechanical, and absorbent properties of glycerol-based polymer films infused with plant cell wall polysaccharides, Abstr. Pap. Am. Chem. Soc. 245(2013) (CELL-164).

[21] M. Vera, A. Almontassir, A. Rodriguez-Galan, J. Puiggali, Synthesis and characterization of a new degradable poly(ester amide) derived from 6-amino-1-hexanol and glutaric acid, Macromolecules 36(26) (2003) 9784-9796.

[22] K. Nemoto, T. Kubo, M. Nomachi, T. Sano, T. Matsumoto, K. Hosoya, T. Hattori, K. Kaya, Simple and effective 3D recognition of domoic acid using a molecularly imprinted polymer, J. Am. Chem. Soc. 129(44) (2007) 13626-13632.

[23] Y. Yu, Z.Y. Wei, C. Zhou, L.C. Zheng, X.F. Leng, Y. Li, Miscibility and competition of cocrystallization behavior of poly (hexamethylene dicarboxylate)s aliphatic copolyesters:effect of chain length of aliphatic diacids, Eur. Polym. J. 92(2017) 71-85.

[24] T. Baba, Y. Tachibana, S. Suda, K. Kasuya, Evaluation of environmental degradability based on the number of methylene units in poly(butylene n-alkylenedionate), Polym. Degrad. Stab. 138(2017) 18-26.

[25] H. Wu, Q. Wang, J.P. Zhu, Organocatalytic enantioselective acyloin rearrangement of alpha-hydroxy acetals to alpha-alkoxy ketones, Angew. Chem. Int. Ed. Eng. 56(21) (2017) 5858-5861.

[26] T. Tabanelli, E. Monti, F. Cavani, M. Selva, The design of efficient carbonate interchange reactions with catechol carbonate, Green Chem. 19(6) (2017) 1519-1528.

[27] Y. Ogawa, K. Yamamoto, C. Miura, S. Tamura, M. Saito, M. Mamada, D. Kumaki, S. Tokito, H. Katagiri, Asymmetric alkylthienyl thienoacenes derived from anthra[2,3-b]thieno[2,3-d]thiophene for solution-processable organic semiconductors, ACS Appl. Mater. Interfaces 9(11) (2017) 9902-9909.

[28] Q.Z. Hu, L.N. Yin, A. Ali, A.J. Cooke, J. Bennett, P. Ratcliffe, M.M.C. Lo, E. Metzger, S. Hoyt, R.W. Hartmann, Novel pyridyl substituted 4,5-dihydro-[1,2,4] triazolo[4,3-a]quinolines as potent and selective aldosterone synthase inhibitors with improved in vitro metabolic stability, J. Med. Chem. 58(5) (2015) 2530-2537.

[29] W.E. Noland, H.V. Kumar, G.C. Flick, C.L. Aspros, J.H. Yoon, A.C. Wilt, N. Dehkordi, S. Thao, A.K. Schneerer, S. Gao, K.J. Tritch, Hydrated ferric sulfate-catalyzed reactions of indole with aldehydes, ketones, cyclic ketones, and chromanones:synthesis of bisindoles and trisindoles, Tetrahedron 73(27-28) (2017) 3913-3922.

[30] J.Y. Shie, J.L. Zhu, Synthesis of bicyclic gamma-butyrolactone derivatives by rhodium catalyzed intramolecular C-H insertion of alpha-dizao alpha-phosphoryl cycloalkyl esters, Tetrahedron 72(12) (2016) 1590-1601.

[31] B.M. Trost, C.E. Stivala, D.R. Fandrick, K.L. Hull, A. Huang, C. Poock, R. Kalkofen, Total synthesis of (-)-lasonolide A, J. Am. Chem. Soc. 138(36) (2016) 11690-11701.

[32] G.S. Machado, O.J. de Lima, K.J. Ciuffi, F. Wypych, S. Nakagaki, Iron(Ⅲ) porphyrin supported on metahalloysite:an efficient and reusable catalyst for oxidation reactions, Catal. Sci. Technol. 3(4) (2013) 1094-1101.

[33] G.M. Ucoski, F.S. Nunes, G. DeFreitas-Silva, Y.M. Idemori, S. Nakagaki, Metalloporphyrins immobilized on silica-coated Fe₃O₄ nanoparticles:magnetically recoverable catalysts for the oxidation of organic substrates, Appl. Catal. A Gen. 459(2013) 121-130.

[34] V.S. da Silva, L.I. Teixeira, E. do Nascimento, Y.M. Idemori, G. DeFreitas-Silva, New manganese porphyrin as biomimetic catalyst of cyclohexane oxidation:effect of water or imidazole as additives, Appl. Catal. A Gen. 469(2014) 124-131.

[35] K.A.D.D. Castro, M.M.Q. Simoes, M.D.P.M.S. Neves, J.A.S. Cavaleiro, R.R. Ribeiro, F. Wypych, S. Nakagaki, Synthesis of new metalloporphyrin derivatives from[5,10,15,20-tetrakis (pentafluorophenyl)porphyrin] and 4-mercaptobenzoic acid for homogeneous and heterogeneous catalysis, Appl. Catal. A Gen. 503(2015) 9-19.

[36] L.D. Zanatta, I.A. Barbosa, F.B. Zanardi, P.C. de Sousa, L.B. Bolzon, A.P. Ramos, O.A. Serra, Y. Iamamoto, Hydrocarbon oxidation by iron-porphyrin immobilized on SBA-15 as biomimetic catalyst:role of silica surface, RSC Adv. 6(106) (2016) 104886-104896.

[37] V.H.A. Pinto, J.S. Reboucas, G.M. Ucoski, E.H. de Faria, B.F. Ferreira, R.A.S.S. Gil, S. Nakagaki, Mn porphyrins immobilized on non-modified and chloropropylfunctionalized mesoporous silica SBA-15 as catalysts for cyclohexane oxidation, Appl. Catal. A Gen. 526(2016) 9-20.

[38] V.S. da Silva, W.C.D. Vieira, A.M. Meireles, G.M. Ucoski, S. Nakagaki, Y.M. Idemori, G. DeFreitas-Silva, Biomimetic oxidation of cyclic and linear alkanes:high alcohol selectivity promoted by a novel manganese porphyrin catalyst, New J. Chem. 41(3) (2017) 997-1006.

[39] V.S. da Silva, A.M. Meireles, D.C.D. Martins, J.S. Reboucas, G. DeFreitas-Silva, Y.M. Idemori, Effect of imidazole on biomimetic cyclohexane oxidation by first-, second-, and third-generation manganese porphyrins using PhIO and PhI(OAc)2 as oxidants, Appl. Catal. A Gen. 491(2015) 17-27.

[40] V.S. da Silva, Y.M. Idemori, G. DeFreitas-Silva, Biomimetic alkane oxidation by iodosylbenzene and iodobenzene diacetate catalyzed by a new manganese porphyrin:water effect, Appl. Catal. A Gen. 498(2015) 54-62.

[41] R. Maheswari, R. Anand, G. Imran, MnTUD-1:synthesis, characterization and catalytic behavior in liquid-phase oxidation of cyclohexane, J. Porous. Mater. 19(3) (2012) 283-288.

[42] D.W. Feng, H.L. Jiang, Y.P. Chen, Z.Y. Gu, Z.W. Wei, H.C. Zhou, Metal-organic frameworks based on previously unknown Zr-8/Hf-8 cubic clusters, Inorg. Chem. 52(21) (2013) 12661-12667.

[43] A. Bellifa, A. Choukchou-Braham, C. Kappenstein, L. Pirault-Roy, Preparation and characterization of MTiX for the catalytic oxidation of cyclohexane, RSC Adv. 4(43) (2014) 22374-22379.

[44] N. Pal, M. Pramanik, A. Bhaumik, M. Ali, Highly selective and direct oxidation of cyclohexane to cyclohexanone over vanadium exchanged NaY at room temperature under solvent-free conditions, J. Mol. Catal. A Chem. 392(2014) 299-307.

[45] Y.M. Yang, N.Y. Liu, S. Qiao, R.H. Liu, H. Huang, Y. Liu, Silver modified carbon quantum dots for solvent-free selective oxidation of cyclohexane, New J. Chem. 39(4) (2015) 2815-2821.

[46] T. Lopez-Ausens, M. Boronat, P. Concepcion, S. Chouzier, S. Mastroianni, A. Corma, A heterogeneous mechanism for the catalytic decomposition of hydroperoxides and oxidation of alkanes over CeO₂ nanoparticles:a combined theoretical and experimental study, J. Catal. 344(2016) 334-345.

[47] L.M.D.R.D. Martins, S.A.C. Carabineiro, J.W. Wang, B.G.M. Rocha, F.J. Maldonado-Hodar, A.J.L.D. Pombeiro, Supported gold nanoparticles as reusable catalysts for oxidation reactions of industrial significance, ChemCatChem 9(7) (2017) 1211-1221.

[48] M.V. Kirillova, C.I.M. Santos, W.Y. Wu, Y. Tang, A.M. Kirillov, Mild oxidative C-H functionalization of alkanes and alcohols using a magnetic core-shell Fe₃O₄@mSiO₂@Cu₄ nanocatalyst, J. Mol. Catal. A Chem. 426(2017) 343-349.

[49] M. Saha, K.M. Vyas, L.M.D.R.S. Martins, N.M.R. Martins, A.J.L. Pombeiro, S.M. Mobin, D. Bhattacherjee, K.P. Bhabak, S. Mukhopadhyay, Copper(Ⅱ) tetrazolato complexes:role in oxidation catalysis and protein binding, Polyhedron 132(2017) 53-63.

[50] S. Hikichi, K. Hanaue, T. Fujimura, H. Okuda, J. Nakazawa, Y. Ohzu, C. Kobayashi, M. Akita, Characterization of nickel(Ⅱ)-acylperoxo species relevant to catalytic alkane hydroxylation by nickel complex with m-CPBA, Dalton Trans. 42(10) (2013) 3346-3356.

[51] J. Nakazawa, T. Hori, T.D.P. Stack, S. Hikichi, Alkane oxidation by an immobilized nickel complex catalyst:structural and reactivity differences induced by surface-ligand density on mesoporous silica, Chem. Asian. J. 8(6) (2013) 1191-1199.

[52] M. Sankaralingam, M. Palaniandavar, Diiron(Ⅲ) complexes of tridentate 3N ligands as functional models for methane monooxygenases:effect of the capping ligand on hydroxylation of alkanes, Polyhedron 67(2014) 171-180.

[53] M. Sankaralingam, M. Balamurugan, M. Palaniandavar, P. Vadivelu, C.H. Suresh, Nickel (Ⅱ) complexes of pentadentate N5 ligands as catalysts for alkane hydroxylation by using m-CPBA as oxidant:a combined experimental and computational study, Chem. Eur. J. 20(36) (2014) 11346-11361.

[54] R.R. Reinig, D. Mukherjee, Z.B. Weinstein, W.W. Xie, T. Albright, B. Baird, T.S. Gray, A. Ellern, G.J. Miller, A.H. Winter, S.L. Bud'ko, A.D. Sadow, Synthesis and oxidation catalysis of[tris(oxazolinyl)borato]cobalt(Ⅱ) scorpionates, Eur. J. Inorg. Chem. (15-16) (2016) 2486-2494.

[55] M. Balamurugan, E. Suresh, M. Palaniandavar, Non-heme μ-Oxo-and bis(μ-carboxylato)-bridged diiron(Ⅲ) complexes of a 3N ligand as catalysts for alkane hydroxylation:stereoelectronic factors of carboxylate bridges determine the catalytic efficiency, Dalton Trans. 45(28) (2016) 11422-11436.

[56] E.H. de Faria, G.P. Ricci, L. Marcal, E.J. Nassar, M.A. Vicente, R. Trujillano, A. Gil, S.A. Korili, K.J. Ciuffi, P.S. Calefi, Green and selective oxidation reactions catalyzed by kaolinite covalently grafted with Fe(Ⅲ) pyridine-carboxylate complexes, Catal. Today 187(1) (2012) 135-149.

[57] S. Cheng, J. Li, X.X. Yu, C.C. Chen, H.W. Ji, W.H. Ma, J.C. Zhao, Selective activation of secondary C-H bonds by an iron catalyst:insights into possibilities created by the use of a carboxyl-containing bipyridine ligand, New J. Chem. 37(10) (2013) 3267-3273.

[58] I. Prat, A. Company, V. Postils, X. Ribas, L. Que, J.M. Luis, M. Costas, The mechanism of stereospecific CH oxidation by Fe(Pytacn) complexes:bioinspired non-Heme iron catalysts containing cis-labile exchangeable sites, Chem. Eur. J. 19(21) (2013) 6724-6738.

[59] M. Grau, A. Kyriacou, F.C. Martinez, I.M. de Wispelaere, A.J.P. White, G.J.P. Britovsek, Unraveling the origins of catalyst degradation in non-heme iron-based alkane oxidation, Dalton Trans. 43(45) (2014) 17108-17119.

[60] M. Chen, Y. Pan, H.K. Kwong, R.J. Zeng, K.C. Lau, T.C. Lau, Catalytic oxidation of alkanes by a (salen)osmium(VI) nitrido complex using H₂O₂ as the terminal oxidant, Chem. Commun. 51(71) (2015) 13686-13689.

[61] S. Urus, H. Achguzel, M. Incesu, Synthesis of novel N₄O₄ type bis(diazoimine)-metal complexes supported on mesoporous silica:microwave assisted catalytic oxidation of cyclohexane, cyclooctane, cyclohexene and styrene, Chem. Eng. J. 296(2016) 90-101.

[62] K.A.D.F. Castro, F.H.C. de Lima, M.M.Q. Simoes, M.G.P.M.S. Neves, F.A.A. Paz, R.F. Mendes, S. Nakagaki, J.A.S. Cavaleiro, Synthesis, characterization and catalytic activity under homogeneous conditions of ethylene glycol substituted porphyrin manganese(Ⅲ) complexes, Inorg. Chim. Acta 455(2017) 575-583.

[63] A.P.C. Ribeiro, L.M.D.R.S. Martins, M.L. Kuznetsov, A.J.L. Pombeiro, Tuning cyclohexane oxidation:combination of microwave irradiation and ionic liquid with the CScorpionate[FeCl₂(Tpm)] catalyst, Organometallics 36(1) (2017) 192-198.

[64] G. Huang, Z.C. Luo, Y.D. Hu, Y.A. Guo, Y.X. Jiang, S.J. Wei, Preparation and characterization of iron tetra (pentaflurophenyl)-porphyrin (TPFPP Fe) supported on boehmite (BM), Chem. Eng. J. 195(2012) 165-172.

[65] Y. Ide, N. Kawamoto, Y. Bando, H. Hattori, M. Sadakane, T. Sano, Ternary modified TiO₂ as a simple and efficient photocatalyst for green organic synthesis, Chem. Commun. 49(35) (2013) 3652-3654.

[66] K. Machado, J. Mishra, S. Suzuki, G.S. Mishra, Synthesis of superparamagnetic carbon nanotubes immobilized Pt and Pd pincer complexes:highly active and selective catalysts towards cyclohexane oxidation with dioxygen, Dalton Trans. 43(46) (2014) 17475-17482.

[67] Y.X. Jiang, T.M. Su, Z.Z. Qin, G. Huang, A zinc sulfide-supported iron tetrakis (4-carboxyl phenyl) porphyrin catalyst for aerobic oxidation of cyclohexane, RSC Adv. 5(31) (2015) 24788-24794.

[68] X. Liu, M. Conte, M. Sankar, Q. He, D.M. Murphy, D. Morgan, R.L. Jenkins, D. Knight, K. Whiston, C.J. Kiely, G.J. Hutchings, Liquid phase oxidation of cyclohexane using bimetallic Au-Pd/MgO catalysts, Appl. Catal. A Gen. 504(2015) 373-380.

[69] X. Wang, Y.W. Li, Nanoporous carbons derived from MOFs as metal-free catalysts for selective aerobic oxidations, J. Mater. Chem. A 4(14) (2016) 5247-5257.

[70] G. Huang, Y. Liu, J.L. Cai, X.F. Chen, S.K. Zhao, Y.A. Guo, S.J. Wei, X. Li, Heterogeneous biomimetic catalysis using iron porphyrin for cyclohexane oxidation promoted by chitosan, Appl. Surf. Sci. 402(2017) 436-443.

[71] D.X. Yang, T.B. Wu, C.J. Chen, W.W. Guo, H.Z. Liu, B.X. Han, The highly selective aerobic oxidation of cyclohexane to cyclohexanone and cyclohexanol over V₂O₅@TiO₂ under simulated solar light irradiation, Green Chem. 19(1) (2017) 311-318.

[72] L.F. Chen, Y.Y. Zhou, Z.Y. Gui, H.Y. Cheng, Z.W. Qi, Au nanoparticles confined in hybrid shells of silica nanospheres for solvent-free aerobic cyclohexane oxidation, J. Mater. Sci. 52(12) (2017) 7186-7198.

[73] K.C. Hwang, A. Sagadevan, One-pot room-temperature conversion of cyclohexane to adipic acid by ozone and UV light, Science 346(6216) (2014) 1495-1498.

[74] A.P.C. Ribeiro, L.M.D.R.S. Martins, A.J.L. Pombeiro, N₂O-free single-pot conversion of cyclohexane to adipic acid catalysed by an iron(Ⅱ) scorpionate complex, Green Chem. 19(6) (2017) 1499-1501.

[75] X. Liu, M. Conte, Q. He, D.W. Knight, D.M. Murphy, S.H. Taylor, K. Whiston, C.J. Kiely, G.J. Hutchings, Catalytic partial oxidation of cyclohexane by bimetallic Ag/Pd nanoparticles on magnesium oxide, Chem. Eur. J. 23(49) (2017) 11834-11842.

[76] Y.P. Xiao, J.C. Liu, Y.T. Lin, W.J. Lin, Y.X. Fang, Novel graphene oxide-silver nanorod composites with enhanced photocatalytic performance under visible light irradiation, J. Alloys Compd. 698(2017) 170-177.

[77] L.M.D.R.S. Martins, M.P. de Almeida, S.A.C. Carabineiro, J.L. Figueiredo, A.J.L. Pombeiro, Heterogenisation of a C-Scorpionate Fe-Ⅱ complex on carbon materials for cyclohexane oxidation with hydrogen peroxide, ChemCatChem 5(12) (2013) 3847-3856.

[78] A. Denicourt-Nowicki, A. Lebedeva, C. Bellini, A. Roucoux, Highly selective cycloalkane oxidation in water with ruthenium nanoparticles, ChemCatChem 8(2) (2016) 357-362.

[79] E. Tabor, J. Poltowicz, K. Pamin, S. Basag, W. Kubiak, Influence of substituents in mesoaryl groups of iron μ-oxo porphyrins on their catalytic activity in the oxidation of cycloalkanes, Polyhedron 119(2016) 342-349.

[80] Z. Feng, Y.J. Xie, F. Hao, P.L. Liu, H.A. Luo, Catalytic oxidation of cyclohexane to KA oil by zinc oxide supported manganese 5,10,15,20-tetrakis(4-nitrophenyl)porphyrin, J. Mol. Catal. A Chem. 410(2015) 221-225.

[81] K. Machado, S. Mukhopadhyay, G.S. Mishra, Nanoparticles silica anchored Cu-(Ⅱ) and V-(IV) scorpionate complexes for selective catalysis of cyclohexane oxidation, J. Mol. Catal. A Chem. 400(2015) 139-146.

[82] S. Saxena, R. Singh, R.G.S. Pala, S. Sivakumar, Sinter-resistant gold nanoparticles encapsulated by zeolite nanoshell for oxidation of cyclohexane, RSC Adv. 6(10) (2016) 8015-8020.

[83] Z.Y. Gui, W.R. Cao, L.F. Chen, Z.W. Qi, Propene carbonate intensified cyclohexane oxidation over Au/SiO₂ catalyst, Catal. Commun. 64(2015) 58-61.

[84] W.Z. Zhong, T. Qiao, J. Dai, L.Q. Mao, Q. Xu, G.Q. Zou, X.X. Liu, D.L. Yin, F.P. Zhao, Visiblelight-responsive sulfated vanadium-doped TS-1 with hollow structure:enhanced photocatalytic activity in selective oxidation of cyclohexane, J. Catal. 330(2015) 208-221.

[85] Y. Fu, W.C. Zhan, Y.L. Guo, Y.Q. Wang, X.H. Liu, Y. Guo, Y.S. Wang, G.Z. Lu, Effect of surface functionalization of cerium-doped MCM-48 on its catalytic performance for liquidphase free-solvent oxidation of cyclohexane with molecular oxygen, Microporous Mesoporous Mater. 214(2015) 101-107.

[86] X.G. Duan, W.M. Liu, L.M. Yue, W. Fu, M.N. Ha, J. Li, G.Z. Lu, Selective oxidation of cyclohexane on a novel catalyst Mg-Cu/SBA-15 by molecular oxygen, Dalton Trans. 44(39) (2015) 17381-17388.

[87] K. Chen, Z.G. Chai, C. Li, L.R. Shi, M.X. Liu, Q. Xie, Y.F. Zhang, D.S. Xu, A. Manivannan, Z.F. Liu, Catalyst-free growth of three-dimensional graphene flakes and graphene/g-C₃N₄ composite for hydrocarbon oxidation, ACS Nano 10(3) (2016) 3665-3673.

[88] X.X. Yang, H.J. Wang, J. Li, W.X. Zheng, R. Xiang, Z.K. Tang, H. Yu, F. Peng, Mechanistic insight into the catalytic oxidation of cyclohexane over carbon nanotubes:kinetic and in situ spectroscopic evidence, Chem. Eur. J. 19(30) (2013) 9818-9824.

[89] H. Wang, Y. Zhang, Y.Y. Guo, L.M. Zhang, Y. Han, X.X. Zhao, Visible-light-driven oxidation of cyclohexane using Cr-supported mesoporous catalysts prepared via phenylfunctionalized mesoporous silica, RSC Adv. 6(44) (2016) 38176-38182.

[90] Y. Yuan, H.B. Ji, Y.X. Chen, Y. Han, X.F. Song, Y.B. She, R.G. Zhong, Oxidation of cyclohexane to adipic acid using Fe-porphyrin as a biomimetic catalyst, Org. Process. Res. Dev. 8(3) (2004) 418-420.

[91] Y. Chen, Y. She, J. Xu, Y. Li, Studies on QSAR of metalloporphyrin catalysts in the oxidation of cyclohexane to adipic acid, Front. Chem. Eng. China 1(2) (2007) 155-161.

[92] H. Li, Y. She, T. Wang, Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane, Front. Chem. Sci. Eng. 6(3) (2012) 356-368.

[93] T. Wang, Y.B. She, H.Y. Fu, H. Li, Selective cyclohexane oxidation catalyzed by manganese porphyrins and co-catalysts, Catal. Today 264(2016) 185-190.

[94] H. Li, Y.B. She, H.Y. Fu, M.J. Cao, J. Wang, T. Wang, Synergistic effect of co-reactant promotes one-step oxidation of cyclohexane into adipic acid catalyzed by manganese porphyrins, Can. J. Chem. 93(7) (2015) 696-701.

[95] M.J. Cao, Y.B. She, H.Y. Fu, Y.M. Yu, H. Li, T. Wang, Rate-limiting step of the iron porphyrin-catalysed oxidation of cyclohexane to adipic acid by DFT method, Mol. Simul. 41(4) (2015) 262-270.