Recently, the team of Yang Qihua and Liu Jian, researchers from the State Key Laboratory of Catalysis Basics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, realized the promotion of catalytic hydrogenation performance through nanoreactor microenvironment control.
The catalytic performance of the enzyme catalyst is directly related to the microenvironment where the active center is located. However, it is extremely challenging to improve the activity and selectivity of artificial catalysts through precise control of the microenvironment.
The hydrogenation of benzoic acid to prepare cyclohexyl formic acid is an important intermediate process for industrial production of nylon 6 raw material caprolactam, but metal nanoparticle catalysts have low activity for this reaction, especially in aprotic solvents. To improve the catalytic activity of metal nanoparticles, the team introduced Ru nanoparticles in nanoreactors modified with organic functional groups (such as amino, triphenylphosphine, diphenylphosphine, and phenyl). Studies have shown that Ru nanoparticles modified in phosphine ligand nanoreactors can efficiently catalyze the hydrogenation of benzoic acid in n-hexane, while Ru nanoparticles in other nanoreactors and commercial Ru / C do not exhibit catalytic activity. Theoretical calculations and experimental results show that the modification of the phosphine ligand changes the ruthenium microenvironment, which induces the preferential adsorption of the aromatic ring of benzoic acid on the Ru metal surface, thereby enhancing its catalytic performance. At the same time, the study also found that the phosphine ligand-modified nanoreactor can greatly enhance the hydrogenation activity of Ru nanoparticles to benzene, toluene, and trifluorotoluene, mainly due to the power supply effect of the phosphine ligand enhances the surface electron density of Ru . The strategy of nanoreactor microenvironment regulation of catalytic activity and selectivity provides new ideas for the development of highly efficient catalytic systems.
This work was supported by the National Natural Science Foundation of China and the Strategic Pioneering Science and Technology Project (B) of the Chinese Academy of Sciences, and was recently published in the "Angewandte Chemie International Edition" in the form of VIP Paper and inside cover articles.
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The installation is as follows.
1. Installation Steps
a) Choose correct installation site, taking installation area, pipeline, transmitter location &
valve location into consideration;
b) Install the meter according to direction mark on sensor;
c) Install the sensor & transmitter on pipeline;
d) Connect transmitter & sensor with 9-pin cable;
e) Start.
a) Sensor stays away from mechanical vibration source, for example, pump. Use flexible pipe to connect meter with pipeline if inevitable. The housing of meter must be standalone, out of touch with any other device. There must be 3 times the size of sensor between 2 sensors if there are many flow meters on the same pipeline, to avoid resonance.
b) Do not install sensor on pipeline that easily expands with hot and contracts with cold, especially near expansion joint, which leads to a worse stability.
c) Sensor stays away from industrial electromagnetic field, such as large generator and transformer, better 5m at least. Such device influences the performance of drive coil and pickoffs. Make sure magnetic field intensity less than 400A/m.
d) Sensor shall be installed on lower pipeline, to be easily full of fluid.
e) Make sure Ex-mark meet application requirements if in hazardous area.
f) Build a sunshade if the meter is under direct solar radiation. g) Keep the meter from corrosive liquid.
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