Selective Oxidation of Alcohols to Carbonyl Compounds over Small Size Colloidal Ru Nanoparticles

Article abstract of DOI:10.1002/cctc.201901249

The selective oxidation of alcohols to corresponding aldehydes is one of the most challenging problems in modern chemistry due to over-oxidation of these products further into corresponding acids and esters. Herein, we report an efficient and eco-friendly method for selective oxidation of aliphatic, unsaturated and aromatic alcohols to aldehydes (>90 %) using small size (2 nm) non-supported colloidal Ru nanoparticles. The selectivity rapidly decreases with increase of the size of nanoparticles (from 2 to 10 nm) or after their deposition over support. X-ray photoelectron spectroscopy suggests that this catalytic performance can be attributed to high content Ru?O species on the surface of small size Ru nanoparticles, which undergo reduction with formation of water and aldehyde and easy oxidation cycles during the reaction according to the Mars-van Krevelen mechanism. The presence of surface oxide layer over small size Ru nanoparticles suppresses over-oxidation of aldehydes to acids.

Full text of DOI:10.1002/cctc.201901249

The Middle-Late Triassic closure of East Paleotethys Ocean:
paleomagnetic evidence from the Baoshan Terrane, West Yunnan of
China
ZHAO Jie 1,2,*, HUANG Baochun2,3, *, YAN Yonggang2
1 State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an
710069, China
2 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese
Academy of Sciences, Beijing 100029, China
3 Key Laboratory of Orogenic Belt and Crust Evolution, Ministry of Education, School of Earth and
Space Sciences, Peking University, Beijing 100871, China
* Corresponding author. Email: zhjie04@foxmail.com, bchuang@pku.edu.cn
Objective
So far there’s still controversy about when, where and how the East Paleotethys Ocean closed due to
the lack of reliable paleomagnetic data from the blocks or terranes located in both sides of the suture,
which prohibits our better understanding of a series of key scientific issues such as how major blocks
of East Asia collided together, and the relationship between the major blocks of East Asia and the
Pangea supercontinent before its breakup. Therefore, this study reports paleomagnetic result from the
limestones of Middle Triassic Hewanjie Formation of Baoshan Terrane, the northernmost extension of
the Sibumasu Block (Fig1). We aim to accurately reconstruct paleogeographic position of the Baoshan
Terrane during this time interval and further discuss the timing and position for the
Sibumasu-Indochina Collision.
This article has been accepted for publication and undergone full peer review but has not been
through the copyediting, typesetting, pagination and proofreading process, which may lead to
differences between this version and the Version of Record. Please cite this article as doi:
10.1111/1755-6724.13847.
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Fig. 1. (a) Schematic tectonic map of Eurasia showing the Cimmerian continent (b) the structural map around the Baoshan area (c)
Geological map of southern Baoshan Terrane in West Yunnan
Methods
Based on field investigation, 2 sections around the Minglang area of Yongde county were selected
for sampling, and 9 sites embracing 108 samples were drilled with a portable gasoline-powered drill
and oriented using magnetic compass. The samples were cut into standard cylindrical specimens ~2.0
cm in height. All the specimens were subject to hybrid demagnetization comprising progressive
thermal demagnetization with temperature interval of 50 ℃ up to 250-300 ℃ followed by alternating
field demagnetization with a field interval of 5mT below 30mT and 10mT up to 90mT. All the
remanence measurements were performed on a 2G-755 cryogenic magnetometer. Both demagnetizer
and magnetometer are installed in a magnetically shielded space with the field inside minimized to
300nT in the Paleomagnetism and Geochronology Laboratory of the Institute of Geology and
Geophysics, Chinese Academy of Sciences.
Results
In general, the demagnetization behaviour of the samples shows a character of 2 components.
After the removal of a low temperature component below 300℃ which is related to the overprint of
present geomagnetic field (PGF), a stable high field component can be isolated from 10-30mT to 90mT
from specimens. The high field components concentrated inside section, while the sub-mean direction
of the two sections have similar inclination ~25° with a declination difference of ~32 ° which is
compatible to strike azimuth difference of the strata, thus we think this is caused by local rotation
relative to the fault activity (Fig 2). If we rotate the mean direction of the Section 2 to that of the
Section 1, we can get a tilt-corrected mean direction of all sites with Ds=95.6°，Is=26.2°，α95=1.8°.
Further fold test gives a negative result probably due to approximate strata dip of the two sections.
Taking all things into consideration, we suggest that the high field component is probably of primary
origin while further study is still needed.
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90
270
32°
a）in-situ
b）tilt-corrected
180
180
Fig2. Equal area of the site-mean high field component (a and b) directions of the Limestone form Middle Triassic Hewanjie formation in
Baoshan terrane with corresponding 95% of confidence circle pre- and post- tilt correction.
Conclusions
The mean direction of the ChRMs defines a paleolatitude of ~ 14 °N for the Baoshan Terrane.
Taking together the previous paleomagnetic study of the Upper Triassic basalts from the Baoshan
Terrane (Zhao et al., 2015), we think the Baoshan terrane is located at a low latitude around 15 °N
during the Middle-Late Triassic. Huang et al. (2016) reported that the Simao Terrane, northern
extension of the Indochina is located at ~16 °N during the Late Triassic. Taking all things into
consideration, we think that the East Paleotethys Ocean have already closed before or during the
Middle-Late Triassic.
Acknowledgments
This work is financially supported by a National Natural Science Foundation of China (NSFC)
project (41190071, 41702229).
References
Huang, K., Opdyke, N.D., 2016. Paleomagnetism of the Upper Triassic rocks from south of the Ailaoshan Suture
and the timing of the amalgamation between the South China and the Indochina Blocks. J. Asian Earth Sci. 119:
118–127.
Zhao, J., Huang, B., Yan, Y., Zhang, D., 2015. Late Triassic paleomagnetic result from the Baoshan Terrane, West
Yunnan of China: Implication for orientation of the East Paleotethys suture zone and timing of the
Sibumasu-Indochina collision. J. Asian Earth Sci. 111: 350–364.
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Appendix 1 Summary of high field characteristic remanent magnetizations from Middle Triassic Hewanjie
Formation, in the Yongde area of Baoshan Terrane.
Site ID
λs(°N) φs(°E) Strike/dip
n/n0
Dg(°) Ig(°) Ds(°) Is(°)
κ
α95(°)
φp(°E)
λp(°N)
Section1
YY29
YY30
23.96
23.96
23.96
23.96
23.96
23.96
99.24
99.24
99.24
99.24
99.24
99.24
330/20
340/20
341/22
346/24
341/23
339/21
11/13 105.3
11/12 100
10/10 104.8
50.9
44.5
47.6
47.1
45.4
44.0
46.6
93.1
93.3
96.0
96.8
97.8
97
35.5
72.4
5.4
3.7
2.9
2.7
8.2
2.0
2.5
3.5
170.0
175.0
173.0
174.3
173.7
173.7
5.2
2.8
26.7 153.2
28.5 278.3
25.3 421.6
YY31
0.8
YY32
8/12
8/10
104.5
106.7
-0.7
-1.4
-0.6
YY33
25.8
46.6
YY34
15/16 105.2
104.1
26.3 366.1
718.7
Submean
95.7
28.0 367.2
Section2
YY39
YY40
23.92
23.92
23.92
99.26
99.26
99.26
13/31
16/34
11/35
8/11
9/12
8/12
140.3
143
48.1 128.5 21.5 300.4
3.2
11.2
5.9
176.4
176.1
177.0
-1.3
-2.6
-0.1
50.6 129.8 21.2
50.9 127.1 21.5
49.9
22.1
89.1
2084
4207
YY41
142.1
141.8
Submean
2.7
128.5 21.4
1.9
Abbreviations are: site ID, site identification; φs, λs, latitude and longitude of the sampling site; Strike/dip, strike azimuth and dip of bed;
n/n0, number of samples joined the calculation/demagnetized; Dg, Ig (Ds, Is), declination and inclination of direction in-situ (after tilt
correction); κ and α95, precision and parameter and the radius on the cone of 95% confidence for mean direction; φp, λp, latitude and
longitude of corresponding virtue geomagnetic pole (VGP) in stratigraphic coordinates.
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