A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation. A detailed kinetic model of 1,3-buta...A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation. A detailed kinetic model of 1,3-butadiene/propyne co-pyrolysis with the sub-mechanism of aromatic hydrocarbon formation is developed and validated on previous 1,3-butadiene and propyne pyrolysis experiments. The model is able to reproduce both the single component pyrolysis and the co-pyrolysis experiments, as well as the synergistic effect between 1,3- butadiene and propyne on the formation of a series of aromatic hydrocarbons. Based on the rate of production and sensitivity analyses, key reaction pathways in the fuel decomposition and aromatic hydrocarbon formation processes are revealed and insight into the synergistic effect on aromatic hydrocarbon formation is also achieved. The synergistic effect results from the interaction between 1,3-butadiene and propyne. The easily happened chain initiation in the 1,3-butadiene decomposition provides an abundant radical pool for propyne to undergo the H-atom abstraction and produce propargyl radical which plays key roles in the formation of aromatic hydrocarbons. Besides, the 1,3-butadiene/propyne co-pyrolysis includes high concentration levels of C3 and C4 precursors simultaneously, which stimulates the formation of key aromatic hydrocarbons such as toluene and naphthalene.展开更多
The removal of trace propyne(C_(3)H_(4))from propyne/propylene(C_(3)H_(4)/C_(3)H_(6))mixtures is a technical and challenging task during the production of polymer-grade propylene in view of their very similar size and...The removal of trace propyne(C_(3)H_(4))from propyne/propylene(C_(3)H_(4)/C_(3)H_(6))mixtures is a technical and challenging task during the production of polymer-grade propylene in view of their very similar size and physical properties.While some progress has been made,it is still very challenging to use some highly stable and commercially available porous materials via an energy-efficient adsorptive separation process.Herein,we report the ultrafine tuning of the pore apertures in type-A zeolites for the highly efficient removal of trace amounts of C_(3)H_(4)from C_(3)H_(4)/C_(3)H_(6)mixtures.The resulting ion-exchanged zeolite 5 A exhibits a large C_(3)H_(4)adsorption capacity(2.3 mmol g^(-1)under 10^(-4)MPa)and high C_(3)H_(4)/C_(3)H_(6)selectivity at room temperature,which were mainly attributed to the ultrafine-tuned pore size that selectively blocks C_(3)H_(6)molecules,while maintaining the stro ng adsorption of C_(3)H_(4)at low pressure region.High purity of C_(3)H_(6)(>99.9999%)can be directly obtained on this material under ambient conditions,as demonstrated by the experimental breakthrough curves obtained for both 1/99 and 0.1/99.9(V V)C_(3)H_(4)/C_(3)H_(6) mixtures.展开更多
For the storage and transportation of flammable and explosive gases,the adsorption by porous materials alternative to the conventional liquefied or compressed gas storage,represented an energy-efficient and environmen...For the storage and transportation of flammable and explosive gases,the adsorption by porous materials alternative to the conventional liquefied or compressed gas storage,represented an energy-efficient and environmentally friendly method.While the ideal porous materials with high uptake,low cost,convenient accessibility,and extraordinary stability are still quite rare.Herein,two robust porous triptycene networks(PTN-66 and PTN-67)were synthesized through Yamamoto coupling reactions.With ultra-high Brunauer-Emmett-Teller(BET)surface area of 4140 m^(2)g^(-1),PTN-66 exhibited high uptake capacities for propyne of 668.8 and 1182.9 cm^(3)g^(-1)at 1 bar/273 and 253 K,respectively,which set new benchmarks for propyne storage.Furthermore,PTN-66 could also be used to separate trace propyne from the propyne/propylene mixture at room temperature.展开更多
The selective hydrogenation of propyne to propylene has attracted great attention in chemical industry for removing trace amount of propyne for producing polymer-grade propylene. As the state-of-the-art catalyst, Pd s...The selective hydrogenation of propyne to propylene has attracted great attention in chemical industry for removing trace amount of propyne for producing polymer-grade propylene. As the state-of-the-art catalyst, Pd suffers from the disadvantage of poor propylene selectivity due to the over-hydrogenation of propylene to propane. We here demonstrate that Pd nanocubes (NCs) coated by zeolitic imidazolate frameworks (i.e., Pd NCs@ZIF-8) can serve as highly active and selective catalysts for propyne selective hydrogenation (PSH). Benefitting from the unique properties and abundant groups of ZIF-8, Pd carbide (Pd-C) is formed on the surface of Pd NCs after thermal treatment, which acts the active sites for PSH to propylene. More importantly, the content of Pd-C can be precisely controlled by altering the calcination temperature without aggregation of Pd NCs and obvious changes in the framework of ZIF-8. The formation of Pd-C on Pd NCs@ZIF-8 can strongly suppress the H2 adsorption, and thus selectively catalyze propyne to propylene. Consequently, the optimized catalyst (i.e., Pd NCs@ZIF-8-100) exhibits a propylene selectivity of 96.4% at a propyne conversion of 93.3% at 35 °C and atmospheric pressure. This work may not only provide an efficient catalyst for PSH, but also shed a new light on the catalytic application of ZIFs.展开更多
基金This work is supported by the National Natural Science Foundation of China （No.51476155, No.51622605, No.91541201）, the National Key Sci- entific Instruments and Equipment Development Program of China （No.2012YQ22011305）, the National Postdoctoral Program for Innovative Talents （No.BX201600100）, and China Postdoctoral Science Foundation （No.2016M600312）.
文摘A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation. A detailed kinetic model of 1,3-butadiene/propyne co-pyrolysis with the sub-mechanism of aromatic hydrocarbon formation is developed and validated on previous 1,3-butadiene and propyne pyrolysis experiments. The model is able to reproduce both the single component pyrolysis and the co-pyrolysis experiments, as well as the synergistic effect between 1,3- butadiene and propyne on the formation of a series of aromatic hydrocarbons. Based on the rate of production and sensitivity analyses, key reaction pathways in the fuel decomposition and aromatic hydrocarbon formation processes are revealed and insight into the synergistic effect on aromatic hydrocarbon formation is also achieved. The synergistic effect results from the interaction between 1,3-butadiene and propyne. The easily happened chain initiation in the 1,3-butadiene decomposition provides an abundant radical pool for propyne to undergo the H-atom abstraction and produce propargyl radical which plays key roles in the formation of aromatic hydrocarbons. Besides, the 1,3-butadiene/propyne co-pyrolysis includes high concentration levels of C3 and C4 precursors simultaneously, which stimulates the formation of key aromatic hydrocarbons such as toluene and naphthalene.
基金financial support from the National Natural Science Foundation of China(21922810,21908153,21908155)program of Innovative Talents of Higher Education Institutions of Shanxithe supported by Cultivate Scientific Research Excellence Programs of Higher Education Institutions in Shanxi(CSREP)。
文摘The removal of trace propyne(C_(3)H_(4))from propyne/propylene(C_(3)H_(4)/C_(3)H_(6))mixtures is a technical and challenging task during the production of polymer-grade propylene in view of their very similar size and physical properties.While some progress has been made,it is still very challenging to use some highly stable and commercially available porous materials via an energy-efficient adsorptive separation process.Herein,we report the ultrafine tuning of the pore apertures in type-A zeolites for the highly efficient removal of trace amounts of C_(3)H_(4)from C_(3)H_(4)/C_(3)H_(6)mixtures.The resulting ion-exchanged zeolite 5 A exhibits a large C_(3)H_(4)adsorption capacity(2.3 mmol g^(-1)under 10^(-4)MPa)and high C_(3)H_(4)/C_(3)H_(6)selectivity at room temperature,which were mainly attributed to the ultrafine-tuned pore size that selectively blocks C_(3)H_(6)molecules,while maintaining the stro ng adsorption of C_(3)H_(4)at low pressure region.High purity of C_(3)H_(6)(>99.9999%)can be directly obtained on this material under ambient conditions,as demonstrated by the experimental breakthrough curves obtained for both 1/99 and 0.1/99.9(V V)C_(3)H_(4)/C_(3)H_(6) mixtures.
基金supported by the National Natural Science Foundation of China(22275062,22031010)Nankai University&Cangzhou Bohai New Area Institute of Green Chemical Engineering(NCC2022-PY-04)。
文摘For the storage and transportation of flammable and explosive gases,the adsorption by porous materials alternative to the conventional liquefied or compressed gas storage,represented an energy-efficient and environmentally friendly method.While the ideal porous materials with high uptake,low cost,convenient accessibility,and extraordinary stability are still quite rare.Herein,two robust porous triptycene networks(PTN-66 and PTN-67)were synthesized through Yamamoto coupling reactions.With ultra-high Brunauer-Emmett-Teller(BET)surface area of 4140 m^(2)g^(-1),PTN-66 exhibited high uptake capacities for propyne of 668.8 and 1182.9 cm^(3)g^(-1)at 1 bar/273 and 253 K,respectively,which set new benchmarks for propyne storage.Furthermore,PTN-66 could also be used to separate trace propyne from the propyne/propylene mixture at room temperature.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21703146 and 51802206)Natural Science Foundation of Jiangsu Province (No. BK20180846)+1 种基金We also acknowledge the financial support from the 111 Project, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology (NANO-CIC)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD),SWC for Synchrotron Radiation. Yong Xu acknowledges the financial support from Guangdong University of Technology.
文摘The selective hydrogenation of propyne to propylene has attracted great attention in chemical industry for removing trace amount of propyne for producing polymer-grade propylene. As the state-of-the-art catalyst, Pd suffers from the disadvantage of poor propylene selectivity due to the over-hydrogenation of propylene to propane. We here demonstrate that Pd nanocubes (NCs) coated by zeolitic imidazolate frameworks (i.e., Pd NCs@ZIF-8) can serve as highly active and selective catalysts for propyne selective hydrogenation (PSH). Benefitting from the unique properties and abundant groups of ZIF-8, Pd carbide (Pd-C) is formed on the surface of Pd NCs after thermal treatment, which acts the active sites for PSH to propylene. More importantly, the content of Pd-C can be precisely controlled by altering the calcination temperature without aggregation of Pd NCs and obvious changes in the framework of ZIF-8. The formation of Pd-C on Pd NCs@ZIF-8 can strongly suppress the H2 adsorption, and thus selectively catalyze propyne to propylene. Consequently, the optimized catalyst (i.e., Pd NCs@ZIF-8-100) exhibits a propylene selectivity of 96.4% at a propyne conversion of 93.3% at 35 °C and atmospheric pressure. This work may not only provide an efficient catalyst for PSH, but also shed a new light on the catalytic application of ZIFs.
