A Highly Efficient Catalyst Au/MCM-41 for Selective Oxidation Cyclohexane Using Oxygen

Lu, Guangjie; Zhao, Rui; Qian, Guangren; Qi, Yanxing; Wang, Xiaolai; Suo, Jishuan

doi:10.1023/b:catl.0000038571.97121.b7

Cited by 128 publications

(24 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…179,186 The total selectivities for KA oil were very high and nearly constant regardless of the conversion; the selectivities were as high as µ99% for smaller 0.2Au n /HAP (n = 1039), whereas the selectivity was slightly smaller (µ95%) for 0.2Au µ85 /HAP. This is in sharp contrast to the previously reported trade-off relationship between conversion and selectivity 181,185 Figure 21 shows a plot of the TOF values (defined as the number of cyclohexane converted per Au atom in the cluster per hour) as a function of cluster size n. The TOF values increase monotonically with increasing size in the range n = 10 to 39, but decrease in the range n = 39 to µ85. Figure 21 reveals that there is an optimal Au cluster size in the range n = 40 to 80 for aerobic oxidation of cyclohexane.…”

Section: Catalysis For Aerobic Oxidation Of Cyclohexanecontrasting

confidence: 64%

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Tsukuda

2012

Bulletin of the Chemical Society of Japan

232

230

View full text Add to dashboard Cite

Metal clusters consisting of fewer than 100 atoms (diameter <2 nm) are highly promising as a new class of building units for functional materials because of their novel and size-dependent properties. Nevertheless, basic and applied studies of metals clusters have been hampered by the lack of specific guidelines for design and precise synthetic methods. This account surveys recent investigations of gold clusters focusing on our effort toward an atomic-level understanding and control of their size-specific properties. We have developed a size-controlled method for synthesizing gold clusters protected by ligands, stabilized by polymers, and supported on solids. Remarkable size-effects on stabilities and various properties including catalysis were observed. Their mechanisms are discussed based on fundamental knowledge of bare gold clusters in the gas phase.

show abstract

Section: Catalysis For Aerobic Oxidation Of Cyclohexanecontrasting

confidence: 64%

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Tsukuda

2012

Bulletin of the Chemical Society of Japan

232

230

View full text Add to dashboard Cite

show abstract

“…The nano-structured Au@TiO 2 / MCM-22 (PR) exhibits extremely higher TOF than the reported gold catalysts [21] [39] [40]. Experiment results also show that the TOF become higher with a decrease in the amount of Au (Table 4).…”

Section: Catalytic Oxidation Of Cyclohexanementioning

confidence: 80%

Preparation of Novel Complex Nano-Structured Gold Catalyst Au@T<sub>i</sub>O<sub>2</sub>/MCM-22, Characterization and Remarkably Catalytic Performance for Cyclohexane Oxidation

Li²,

Zhang

et al. 2017

MRC

View full text Add to dashboard Cite

A novel complex nano-structured Au@TiO 2 gold catalyst has been prepared. Au precursor could be transformed into Au@TiO 2 /MCM-22 with the complex nano-structured using two different methods. Samples were characterized by XRD, FT-IR, UV-vis, TEM, ICP-AES and N 2 adsorption-desorption. It is found that gold was anchored on the TiO 2 /MCM-22 as small size and uniform particles with the average diameters in the range of 5 -9 nm. Catalytic results show that such nano-gold catalysts display excellent catalytic performance for cyclohexane oxidation. Au@TiO 2 /MCM-22 catalyst with the gold content of 0.5 wt% exhibits extremely exceptionally catalytic activity (12.81%) and high turnover frequency (52,121 h −1 ), which may be ascribed to the synergistic effects of Au and TiO 2 in the complex nano-structured catalyst Au@TiO 2 / MCM-22. Because of the strong metal support interaction, aggregation of active sites (Au nanoparticles) during the oxidation reaction is effectively prohibited and the catalytic activity is essentially retained.

show abstract

“…The industrial scale production of KA oil was carried out in twoconsecutive-step process: the noncatalytic autoxidation of cyclohexane to cyclohexyl hydroperoxide (CHHP) in the presence of oxygen, followed by the conversion CHHP to KA oil using a homogeneous cobalt (Co(II)) catalyst. This process has limitations of low cyclohexane conversion of 3-4% with selectivity of 60-70% to CHHP [13], high operation cost of recycling of unreacted cyclohexane, partial recovery of Co(II) catalyst due to its easy discharge with the salts leaving the process, and use of 180 Kg of NaOH to produce a single Kg of KA oil; this in turn generates 1100 Kg of alkaline waste [14]. The environmental and economical shortcomings of the industrial scale selective oxidation of cyclohexane to KA oil were reduced by using a heterogeneous catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, most of these catalysts have been utilized in the presence of a solvent [15,16] and an expensive oxidant [17]. Several catalytic systems, such as FeRu, FeCo nanoclusters, supported Co catalyst, polymer supported cobaltous palmitate, and Co-salen complex immobilized on silica [18], Au/MCM-41 [13], gold nanoparticles immobilized upon mesoporous silica [19], Au nanoclusters on hydroxyapatite [17], metallophthalocyanines supported on -alumina [20], and chromium containing silicate [21], have been devised in solvent-free condition and presence of molecular oxygen. These catalysts in general have limitations of poor catalytic activity, loss of sensitivity, low selectivity, and high cost.…”

Section: Introductionmentioning

confidence: 99%

Tuning of Activated Carbon for Solvent-Free Oxidation of Cyclohexane

Sadiq

Khan

Numan

et al. 2017

Journal of Chemistry

View full text Add to dashboard Cite

Activated carbon (AC) was prepared from carbonization of phosphoric acid soaked peanut shell at 380 ∘ C under inert atmosphere followed by activation with hydrogen peroxide. The AC was characterized by SEM, EDX, FTIR, TGA, and BET surface area and pore size analyzer. The potential of AC as a catalyst for solvent-free oxidation of cyclohexane to cyclohexanol and cyclohexanone (the mixture is known as KA oil) in the presence of molecular oxygen at moderate temperature was investigated in a self-designed double-walled three-necked batch reactor. The effect of different reaction parameters/additive was optimized. The maximum productivity value (2.14 mmolg −1 h −1 , without base, and 4.85 mmolg −1 h −1 , with 0.2 mmol NaOH) of the desired product was achieved under optimal reaction parameters: vol 12.5 mL, cat 0.4 g, time 14 h, oxygen flow 40 mL/min (pO 2 760 Torr), stirring 1100 rpm, and temp 75∘ C. The AC shows recyclability for multiple runs without any significant loss in activity. Thus, the AC can be an efficient catalyst, due to low cost, ease of synthesis, easy recovery, nonleaching, and recyclability for multiple uses for the solvent-free oxidation of cyclohexane.

show abstract

A Highly Efficient Catalyst Au/MCM-41 for Selective Oxidation Cyclohexane Using Oxygen

Cited by 128 publications

References 26 publications

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Preparation of Novel Complex Nano-Structured Gold Catalyst Au@T<sub>i</sub>O<sub>2</sub>/MCM-22, Characterization and Remarkably Catalytic Performance for Cyclohexane Oxidation

Tuning of Activated Carbon for Solvent-Free Oxidation of Cyclohexane

Contact Info

Product

Resources

About

A Highly Efficient Catalyst Au/MCM-41 for Selective Oxidation Cyclohexane Using Oxygen

Cited by 128 publications

References 26 publications

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Toward an Atomic-Level Understanding of Size-Specific Properties of Protected and Stabilized Gold Clusters

Preparation of Novel Complex Nano-Structured Gold Catalyst Au@T&lt;sub&gt;i&lt;/sub&gt;O&lt;sub&gt;2&lt;/sub&gt;/MCM-22, Characterization and Remarkably Catalytic Performance for Cyclohexane Oxidation

Tuning of Activated Carbon for Solvent-Free Oxidation of Cyclohexane

Contact Info

Product

Resources

About

Preparation of Novel Complex Nano-Structured Gold Catalyst Au@T<sub>i</sub>O<sub>2</sub>/MCM-22, Characterization and Remarkably Catalytic Performance for Cyclohexane Oxidation