591-48-0Relevant articles and documents
Selective production of bio-based: Para -xylene over an FeOx -modified Pd/Al2O3catalyst
Fu, Zaihui,Li, Changzhi,Meng, Qingwei,Pan, Xiaoli,Xiao, Yuxue,Zhang, Chao
supporting information, p. 4341 - 4349 (2020/07/14)
para-Xylene (PX) is a basic building block of polyethylene terephthalate, which is currently produced from petroleum resources. Developing a renewable route to PX is highly desirable to address both economic and environmental concerns. Several attempts used noble metal catalysts, e.g. Pd/Al2O3, to synthesize PX from biomass-derived 4-methyl-3-cyclohexene-1-carboxaldehyde (4-MCHCA), but suffered from a severe decarbonylation reaction, resulting in toluene as the main product. In this paper, we report an FeOx modification strategy to suppress the decarbonylation reaction on a Pd/Al2O3 catalyst, leading to a drastic shift in selectivity towards PX with a yield up to 81percent via a cascade dehydroaromatization-hydrodeoxygenation (DHA-HDO) pathway. Characterization and control experiments revealed that the electron density of Pd sites decreased in an FeOx-modified Pd/Al2O3 catalyst compared to Pd/Al2O3, thus tuning the preferential adsorption mode of the substrate from η2-(C,O), the key transition state of the decarbonylation reaction, to the η1-(O) mode that favors the hydrodeoxygenation process. Notably, this designed catalyst is highly stable and is readily applicable in the selective synthesis of a broad range of desired aromatic chemicals via the same DHA-HDO pathway from cyclohex-3-enecarbaldehyde derivatives. Overall, this work develops a controllable catalyst modification strategy that tailors an efficient catalyst for petroleum-independent bio-PX synthesis.
Cobalt-catalyzed oxidative esterification of allylic/benzylic C(sp3)–H bonds
Ren, Tian-Lu,Xu, Bao-Hua,Mahmood, Sajid,Sun, Ming-Xue,Zhang, Suo-Jiang
supporting information, p. 2943 - 2948 (2017/04/26)
A protocol for the cobalt-catalyzed oxidative esterification of allylic/benzylic C(sp3)–H bonds with carboxylic acids was developed in this work. Mechanistic studies revealed that C(sp3)–H bond activation in the hydrocarbon was the turnover-limiting step and the in-situ formed [Co(III)]Ot-Bu did not engage in hydrogen atom abstraction (HAA) of a C–H bond. This protocol was successfully incorporated into a synthetic pathway to β-damascenone that avoided the use of NBS.
Microwave-assisted hydrothermal synthesis of NiSx and their promotional effect for the hydrodeoxygenation of p-cresol on MoS2
Wang, Weiyan,Wu, Kui,Li, Lu,Tan, Song,Zhu, Guohua,Li, Wensong,He, Zhiqiang,Yang, Yunquan
, p. 60 - 64 (2015/11/17)
NiSx were synthesized by microwave assisted hydrothermal method using nickel nitrate and thiourea as precursor materials. Their phase compositions were controlled by adjusting the reaction temperature and pH value. In the hydrodeoxygenation (HDO) of p-cresol on MoS2, adding NiSx enhanced the conversion but had no effect on the product distribution. NiS2 phase exhibited higher promotional effect than NiS and Ni3S4 phases. The HDO reaction mechanism for p-cresol on NiSx + MoS2 could be well explained by the Remote Control model through a migration of spillover hydrogen.
Highly selective catalytic conversion of phenols to aromatic hydrocarbons on CoS2/MoS2 synthesized using a two step hydrothermal method
Wang, Weiyan,Li, Lu,Wu, Kui,Zhu, Guohua,Tan, Song,Liu, Yan,Yang, Yunquan
, p. 31265 - 31271 (2016/04/08)
CoS2/MoS2 catalysts were prepared using a two-step hydrothermal procedure for the first time, i.e., MoS2 was synthesized and then CoS2 was prepared and deposited on the surface of the MoS2. The characterization results presented that CoS2 and MoS2 are separated in the resultant catalysts and the surface area of CoS2/MoS2 was much higher than that of Co-Mo-S prepared using a one step method. In the hydrodeoxygenation (HDO) of p-cresol, the presence of CoS2 enhanced the conversion, but excessive CoS2 on the surface of the MoS2 reduced its activity. With an appropriate amount of CoS2, the catalyst presented an unprecedented HDO activity and direct deoxygenation (DDO) selectivity: 98% deoxygenation degree with a selectivity of 99% toluene at 250 °C for 1 h. This CoS2/MoS2 catalyst also exhibited high DDO activity for other phenolic monomers, which minimized hydrogen consumption and improved the economic efficiency.
Dehydrogenation of cycloalkanes at rhodium complexes bearing fluorinated cyclopentadienyl ligands
Liebau, Frank,Braun, Thomas,Braun, Beatrice
, p. 192 - 200 (2015/10/28)
The fluorinated cyclopentadienyl complexes [Rh(η5-C5H4CH2CH2C6F13)(CO)2] (2), [Rh(η5-C5H4CH2CH2C8F17)(CO)2] (3), [Rh(η5-C5H4CH2CH2C10F21)(CO)2] (4), [Rh(η5-C5H4CH2CH2CnF2n+1)(CO)(PEt3)] (7: n = 6; 8: n = 8; 9: n = 10) and [Rh(η5-C5H4CH2CH2CnF2n+1)(CO){P(CH2CH2C6F13)3}] (10: n = 8; 11: n = 10) were synthesized and their reactivity was investigated. Compound 3 converts at room temperature into the trinuclear complex [Rh2(η5-C5H4CH2CH2C8F17)2(μ-CO)2Rh(η5-C5H4CH2CH2C8F17)(CO)] (6). The complexes 9 and 11 were employed in dehydrogenation reactions of cycloalkanes in C6F14/hydrocarbon mixtures. Photocatalytic conversions were observed and a turnover number of 16 for the dehydrogenation of cyclooctane with complex 11 was obtained.
Synthesis of Ni-P-B amorphous nanoparticles with uniform size as a potential hydrodeoxygenation catalyst
Wang, Weiyan,Liu, Pengli,Wu, Kui,Zhang, Kun,Li, Lu,Qiao, Zhiqiang,Yang, Yunquan
supporting information, p. 813 - 816 (2015/02/19)
An Ni-P-B amorphous nano-catalyst was synthesized using a facile chemical reduction method. The amorphous degree was enhanced and the transferred electron decreased with an increase of P content in Ni-P-B. In the hydrodeoxygenation (HDO) of p-cresol, the conversion using Ni-P-B was high up to 98.9% with a selectivity of 6.5% for toluene and a deoxygenation degree of 96.8% at 498 K.
Preparation of Ni-Mo-S catalysts by hydrothermal method and their hydrodeoxygenation properties
Wang, Weiyan,Li, Lu,Wu, Kui,Zhang, Kun,Jie, Jia,Yang, Yunquan
, p. 8 - 16 (2015/09/28)
Unsupported Ni-Mo-S catalysts with different Ni/(Ni + Mo) molar ratio were prepared by hydrothermal method using ammonium heptamolybdate and thiocarbamide as materials. The resultant catalysts were characterized by X-ray diffraction, nitrogen physisorption and transmission electron microscopy, and their activities were measured using the hydrodeoxygenation (HDO) of p-cresol as a probe reaction. The addition of Ni promoter caused a reduction in the surface area. The peaks attributed to NiS2 on catalyst surface became noticeable as the Ni content increased in the catalyst. The catalyst with an optimal Ni/(Ni + Mo) molar ratio (0.3) exhibited the highest activity (99.8% deoxgenation degree at 300 °C and 4.0 MPa hydrogen pressure for 6 h). The HDO of p-cresol on these prepared Ni-Mo-S catalysts proceeded with two parallel routes: hydrogenation-dehydration (HYD) and direct deoxygenation (DDO), and HYD/DDO closely related to the Ni/(Ni + Mo) molar ratio in the catalyst, the HDO reaction temperature and H2 pressure. The comparison of Ni-Mo-S with MoS2-NiS2 (prepared by two hydrothermal method) and MoS2 + NiS2 (prepared by physically mixing separately MoS2 and NiS2) indicated that the high HDO activity of Ni promoted MoS2 catalyst was attributed to the synergistic effect of MoS2 and NiS2 rather than the formation of Ni-Mo-S phase, which could be well explained by the remote control model.
SDBS-assisted hydrothermal synthesis of flower-like Ni-Mo-S catalysts and their enhanced hydrodeoxygenation activity
Wang, Weiyan,Tan, Song,Zhu, Guohua,Wu, Kui,Tan, Liang,Li, Yingze,Yang, Yunquan
, p. 94040 - 94045 (2015/11/17)
Ni-Mo-S catalysts were prepared by sodium dodecyl benzene sulfonate (SDBS) assisted hydrothermal synthesis. The presence of SDBS increased the NiS2 crystallite size, enlarged the interlayer distance of MoS2 plane and formed loose flo
Synthesis of piperylene and toluene via transfer dehydrogenation of pentane and pentene
Kundu, Sabuj,Lyons, Thomas W.,Brookhart, Maurice
, p. 1768 - 1773 (2013/09/02)
The highly thermally stable anthraphos-based iridium pincer complex ( iPr4Anthraphos)Ir(C2H4) 3, was shown to catalyze transfer dehydrogenation of pentene and pentane using various olefins as acceptors in the temperature range of 160-250 C. Using pentene itself as an acceptor, disproportionation of pentene to pentane and pentadiene was observed, but yields of (E)- and (Z)-1,3-pentadienes (piperylenes) were limited to ～25% as a result of a self-Diels-Alder reaction of the 1,3-dienes to produce isomeric mixtures of the C10 dimers. Using propylene as the acceptor, higher yields of piperylenes were obtained (～40%), but self-Diels-Alder adducts were again observed along with low fractions of propylene/pentadiene Diels-Alder adducts. Using ethylene as the acceptor, the pentadienes produced via hydrogen transfer undergo an in situ Diels-Alder reaction with ethylene to produce 3-methylcyclohexene (along with toluene from further dehydrogenation) in good yields (65%). 3-Methylcylohexene was quantitatively dehydrogenated to toluene over a heterogeneous Pd/C catalyst.
Enantioselective synthesis of chiral sulfones by ir-catalyzed asymmetric hydrogenation: A facile approach to the preparation of chiral allylic and homoallylic compounds
Zhou, Taigang,Peters, Byron,Maldonado, Matias F.,Govender, Thavendran,Andersson, Pher G.
, p. 13592 - 13595 (2012/10/08)
A highly efficient and enantioselective Ir-catalyzed hydrogenation of unsaturated sulfones was developed. Chiral cyclic and acyclic sulfones were produced in excellent enantioselectivities (up to 98% ee). Coupled with the Ramberg-Baecklund rearrangement, this reaction offers a novel route to chiral allylic and homoallylic compounds in excellent enantioselectivities (up to 97% ee) and high yields (up to 94%).
