CAS Dalian Institute of Chemical Physics

Dalian, China

CAS Dalian Institute of Chemical Physics

Dalian, China
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Patent
CAS Dalian Institute of Chemical Physics | Date: 2015-12-14

An ionic conductance measuring instrument comprising a voltage/current test device and a test electrode, in which the test electrode comprises a bulk substrate with four linearly arranged through holes, four Pt wires inserted in the through holes respectively with their upper ends exposed outside of the bulk and their downside ends hidden inside of the bulk; the four axis of the Pt wire is in the same plane and parallel with each other; the gap distance between the mentioned Pt wire and the bulk substrate is 0.1-2 mm, and is filled with ionic conductive polymer.


Patent
CAS Dalian Institute of Chemical Physics | Date: 2014-06-04

A method for preparing p-xylene and co-producing propylene with a high selectivity, comprising: a) bringing a raw material containing toluene and methanol and/or dimethyl ether into contact with a catalyst in a reaction system for reaction; returning an ethylene-enriched C_(2)^() component discharged from the reaction system to the reaction system, and continuing the reaction with the raw material on the catalyst to produce propylene; b) separating a C_(6)^(+ )component discharged from the reaction system to obtain a product p-xylene; and c) separating a C_(3 )component discharged from the reaction system to obtain a product propylene.


Patent
CAS Dalian Institute of Chemical Physics | Date: 2017-07-05

Provided is a method for preparing a Y type molecular sieve having a high silica-to-alumina ratio, comprising: mixing deionized water, a silicon source, an aluminum source, an alkali source, and a tetraalkylammoniumcation source as a template agent to obtain an initial gel mixture; after aging the initial gel mixture at an appropriate temperature, feeding the gel mixture into a high pressure synthesis kettle for crystallization; separating a solid product, and drying to obtain the Y type molecular sieve having a high silica-to-alumina ratio. The method provides a phase-pure Y type molecular sieve having a high crystallinity, the SiO_(2)/Al_(2)O_(3) thereof being not less than 6.


Patent
Corning Inc. and CAS Dalian Institute of Chemical Physics | Date: 2016-11-10

Extruded honeycomb catalyst bodies and methods of manufacturing same. The catalyst body includes a first oxide selected from the group consisting of tungsten oxides, vanadium oxides, and combinations thereof, a second oxide selected from the group consisting of cerium oxides, lanthanum oxides, zirconium oxides, and combinations thereof, and a zeolite.


Patent
CAS Dalian Institute of Chemical Physics | Date: 2014-06-04

This invention relates to a method for preparing p-xylene and propylene from methanol and/or dimethyl ether. This method comprises coupling two reaction processes, an aromatization reaction of methanol and/or dimethyl ether and an alkylation reaction of ethylene with methanol and/or dimethyl ether. The method of this invention produces p-xylene and propylene with a high selectivity by returning an ethylene-enriched component in reaction byproducts from preparation of p-xylene from methanol and/or dimethyl ether to the reaction system for performing alkylation reaction with methanol and/or dimethyl ether in the presence of catalysts.


Patent
CAS Dalian Institute of Chemical Physics | Date: 2017-04-12

This invention relates to a method for preparing p-xylene and co-producing propylene with a high selectivity. Toluene and methanol and/or dimethyl ether as raw materials are brought into contact with a catalyst in a reaction system for reaction, and after the resultant product is separated via a separation system, an ethylene-enriched C_(2)^(-) component (hydrocarbons having carbon number less than or equal to 2, CO, CO_(2), and H_(2)) therein is returned to the reaction system for further reaction, a C_(6)^(+) component (aromatic hydrocarbons having carbon number greater than or equal to 6) is subjected to further separation to obtain p-xylene, and a C_(3) component (propylene and propane having a carbon number equal to 3) is subjected to further separation to obtain propylene. This method prepares p-xylene and co-produces propylene with a high selectivity, by coupling two reaction processes, an alkylation reaction of toluene with methanol and/or dimethyl ether and an alkylation reaction of ethylene with methanol and/or dimethyl ether, recycling an ethylene-enriched C_(2)^(-) component in reaction byproducts of alkylation of toluene and methanol and/or dimethyl ether, and performing alkylation reaction with methanol and/or dimethyl ether in the presence of catalysts.


Patent
CAS Dalian Institute of Chemical Physics | Date: 2017-04-12

This invention relates to a method for preparing p-xylene and propylene from methanol and/or dimethyl ether. This method comprises coupling two reaction processes, an aromatization reaction of methanol and/or dimethyl ether and an alkylation reaction of ethylene with methanol and/or dimethyl ether. The method of this invention produces p-xylene and propylene with a high selectivity by returning an ethylene-enriched component in reaction byproducts from preparation of p-xylene from methanol and/or dimethyl ether to the reaction system for performing alkylation reaction with methanol and/or dimethyl ether in the presence of catalysts.


Zhao G.-J.,CAS Dalian Institute of Chemical Physics | Han K.-L.,CAS Dalian Institute of Chemical Physics
Accounts of Chemical Research | Year: 2012

Because of its fundamental importance in many branches of science, hydrogen bonding is a subject of intense contemporary research interest. The physical and chemical properties of hydrogen bonds in the ground state have been widely studied both experimentally and theoretically by chemists, physicists, and biologists. However, hydrogen bonding in the electronic excited state, which plays an important role in many photophysical processes and photochemical reactions, has scarcely been investigated.Upon electronic excitation of hydrogen-bonded systems by light, the hydrogen donor and acceptor molecules must reorganize in the electronic excited state because of the significant charge distribution difference between the different electronic states. The electronic excited-state hydrogen-bonding dynamics, which are predominantly determined by the vibrational motions of the hydrogen donor and acceptor groups, generally occur on ultrafast time scales of hundreds of femtoseconds. As a result, state-of-the-art femtosecond time-resolved vibrational spectroscopy is used to directly monitor the ultrafast dynamical behavior of hydrogen bonds in the electronic excited state. It is important to note that the excited-state hydrogen-bonding dynamics are coupled to the electronic excitation. Fortunately, the combination of femtosecond time-resolved spectroscopy and accurate quantum chemistry calculations of excited states resolves this issue in laser experiments. Through a comparison of the hydrogen-bonded complex to the separated hydrogen donor or acceptor in ground and electronic excited states, the excited-state hydrogen-bonding structure and dynamics have been obtained. Moreover, we have also demonstrated the importance of hydrogen bonding in many photophysical processes and photochemical reactions.In this Account, we review our recent advances in electronic excited-state hydrogen-bonding dynamics and the significant role of electronic excited-state hydrogen bonding on internal conversion (IC), electronic spectral shifts (ESS), photoinduced electron transfer (PET), fluorescence quenching (FQ), intramolecular charge transfer (ICT), and metal-to-ligand charge transfer (MLCT). The combination of various spectroscopic experiments with theoretical calculations has led to tremendous progress in excited-state hydrogen-bonding research. We first demonstrated that the intermolecular hydrogen bond in the electronic excited state is greatly strengthened for coumarin chromophores and weakened for thiocarbonyl chromophores. We have also clarified that the intermolecular hydrogen-bond strengthening and weakening correspond to red-shifts and blue-shifts, respectively, in the electronic spectra. Moreover, radiationless deactivations (via IC, PET, ICT, MLCT, and so on) can be dramatically influenced through the regulation of electronic states by hydrogen-bonding interactions. Consequently, the fluorescence of chromophores in hydrogen-bonded surroundings is quenched or enhanced by hydrogen bonds. Our research expands our understanding of the nature of hydrogen bonding by delineating the interaction between hydrogen bonds and photons, thereby providing a basis for excited-state hydrogen bonding studies in photophysics, photochemistry, and photobiology. © 2011 American Chemical Society.


Li Y.,CAS Dalian Institute of Chemical Physics | Shen W.,CAS Dalian Institute of Chemical Physics
Chemical Society Reviews | Year: 2014

Nanocatalysts are characterised by the unique nanoscale properties that originate from their highly reduced dimensions. Extensive studies over the past few decades have demonstrated that the size and shape of a catalyst particle on the nanometre scale profoundly affect its reaction performance. In particular, controlling the catalyst particle morphology allows a selective exposure of a larger fraction of the reactive facets on which the active sites can be enriched and tuned. This desirable surface coordination of catalytically active atoms or domains substantially improves catalytic activity, selectivity, and stability. This phenomenon is called morphology-dependent nanocatalysts: catalyst particles with anisotropic morphologies on the nanometre scale greatly affect the reaction performance by selectively exposing the desired facets. In this review, we highlight important progress in morphology-dependent nanocatalysts based on the use of rod-shaped metal oxides with characteristic redox and acid-base features. The correlation between the catalytic properties and the exposed facets verifies the chemical nature of the morphology effect. Moreover, we provide an overview of the interactions between the rod-shaped oxides and the metal nanoparticles in metal-oxide catalyst systems, involving crystal-facet-selective deposition of metal particles onto different crystal facets in the oxide supports. A fundamental understanding of active sites in morphologically tuneable oxides enclosed by the desired reactive facets is expected to direct the development of highly efficient nanocatalysts. © 2014 The Royal Society of Chemistry.


Wang A.,CAS Dalian Institute of Chemical Physics | Zhang T.,CAS Dalian Institute of Chemical Physics
Accounts of Chemical Research | Year: 2013

With diminishing fossil resources and increasing concerns about environmental issues, searching for alternative fuels has gained interest in recent years. Cellulose, as the most abundant nonfood biomass on earth, is a promising renewable feedstock for production of fuels and chemicals. In principle, the ample hydroxyl groups in the structure of cellulose make it an ideal feedstock for the production of industrially important polyols such as ethylene glycol (EG), according to the atom economy rule. However, effectively depolymerizing cellulose under mild conditions presents a challenge, due to the intra- and intermolecular hydrogen bonding network. In addition, control of product selectivity is complicated by the thermal instabilities of cellulose-derived sugars. A one-pot catalytic process that combines hydrolysis of cellulose and hydrogenation/hydrogenolysis of cellulose-derived sugars proves to be an efficient way toward the selective production of polyols from cellulose.In this Account, we describe our efforts toward the one-pot catalytic conversion of cellulose to EG, a typical petroleum-dependent bulk chemical widely applied in the polyester industry whose annual consumption reaches about 20 million metric tons. This reaction opens a novel route for the sustainable production of bulk chemicals from biomass and will greatly decrease the dependence on petroleum resources and the associated CO2 emission. It has attracted much attention from both industrial and academic societies since we first described the reaction in 2008. The mechanism involves a cascade reaction. First, acid catalyzes the hydrolysis of cellulose to water-soluble oligosaccharides and glucose (R1). Then, oligosaccharides and glucose undergo C-C bond cleavage to form glycolaldehyde with catalysis of tungsten species (R2). Finally, hydrogenation of glycolaldehyde by a transition metal catalyst produces the end product EG (R3). Due to the instabilities of glycolaldehyde and cellulose-derived sugars, the reaction rates should be r1 r 2 r3 in order to achieve a high yield of EG. Tuning the molar ratio of tungsten to transition metal and changing the reaction temperature successfully optimizes this reaction. No matter what tungsten compounds are used in the beginning reaction, tungsten bronze (H xWO3) is always formed. It is then partially dissolved in hot water and acts as the active species to homogeneously catalyze C-C bond cleavage of cellulose-derived sugars. Upon cooling and exposure to air, the dissolved HxWO3 is transformed to insoluble tungsten acid and precipitated from the solution to facilitate the separation and recovery of the catalyst. On the basis of this temperature-dependent phase-transfer behavior, we have developed a highly active, selective, and reusable catalyst composed of tungsten acid and Ru/C. Our work has unearthed new understanding of this reaction, including how different catalysts perform and the underlying mechanism. It has also guided researchers to the rational design of catalysts for other reactions involved in cellulose conversion. © 2013 American Chemical Society.

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