Owing to its two unsymmetrical-NH2 groups sited on different terminals, 2, 6-diaminocaproic acid (lysine) was used as a reactant for synthesizing a novel unsymmetrical Schiff base with salicylaldehyde on one side and ...Owing to its two unsymmetrical-NH2 groups sited on different terminals, 2, 6-diaminocaproic acid (lysine) was used as a reactant for synthesizing a novel unsymmetrical Schiff base with salicylaldehyde on one side and ovanillin on the other for the first time. It is a new way to synthesize such a special unsymmetrical Schiff base. It is named “hetero bis-Schiff base” for distinguishing it from others. The synthesis method, formation mechanism as well as twelve new lanthaniHe complexes with the above ligand are reported and discussed herein. They were characterized by elementary analysis, molar conductivity, IR-spectra and especially by1H and13C NMR spectra. The results obtained may provide a new promising method for synthesizing similar unsymmetrical Schiff bases and their complexes.展开更多
Three guests with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-ada...Three guests with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-guest complexes of Cucurbit[n = 6—8]urils with these guests have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-guest complexes.展开更多
Tight oil resources are abundant in the world.It is very important to strengthen the research on the development theory and technology of tight oil reservoirs for ensuring national energy security.Natural gas huff-n-p...Tight oil resources are abundant in the world.It is very important to strengthen the research on the development theory and technology of tight oil reservoirs for ensuring national energy security.Natural gas huff-n-puff can effectively improve the oil recovery of tight oil reservoirs.However,the pore-scale oil production characteristics and the mechanisms of natural gas huff-n-puff in matrix-fracture cores are poorly understood.The influence degree of important factors on oil recovery is not clear and the interactions between factors are rarely considered.In this paper,the oil production characteristics and mechanisms of natural gas huff-n-puff in tight cores with different fracture lengths were quantitatively analyzed by combining nuclear magnetic resonance(NMR)with numerical simulation technology.The influencing factors and their interactions were evaluated by the response surface method(RSM).The results show that tight cores mainly consist of medium pores(0.1–1μm)and small pores(0.01–0.1μm).The fracture mainly increases the proportion of macro-pores(1–10μm)and medium pores.In the natural gas huff-n-puff process,crude oil from macro-pores(1–10μm)and medium pores is mainly developed,and the contribution percentage of crude oil in medium pores to oil recovery is the largest,up to 98.28%.The position of gas–oil contact(GOC)moves deeper as the number of huff-n-puff cycles increases.The contents of CH_(4) and CO_(2) in the oil phase remain at a high level within the GOC,while between the GOC and the component sweep front,the contents of CH_(4) and CO_(2) in the oil phase decrease with the increase in dimensionless distance.The gas component sweep volume is increasing with the increase in fracture length.Moreover,the injected natural gas mainly extracts C_(3)–C_(10) components from crude oil.The reduction law of crude oil viscosity is consistent with the migration laws of CH_(4) components along the path.Compared with soaking time and gas diffusion coefficient,the injection pressure is the most signi展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 29671026)the Natural Science Foundation of Zhejiang Province (Grant No. 296062)the Laboratory of MRAMP (Grant No. 971502)
文摘Owing to its two unsymmetrical-NH2 groups sited on different terminals, 2, 6-diaminocaproic acid (lysine) was used as a reactant for synthesizing a novel unsymmetrical Schiff base with salicylaldehyde on one side and ovanillin on the other for the first time. It is a new way to synthesize such a special unsymmetrical Schiff base. It is named “hetero bis-Schiff base” for distinguishing it from others. The synthesis method, formation mechanism as well as twelve new lanthaniHe complexes with the above ligand are reported and discussed herein. They were characterized by elementary analysis, molar conductivity, IR-spectra and especially by1H and13C NMR spectra. The results obtained may provide a new promising method for synthesizing similar unsymmetrical Schiff bases and their complexes.
文摘Three guests with two moiety probes for different Cucurbit[n = 6—8]urils have been synthesized. They are N-(2-methylenethiophen)-adamataneamine, N-(2-methylene pyrrole)- adamataneamine and N-(2-methylenefurfuran)-adamataneamine. The probes are methyle-nepyridyl typically for Q[6] and adamataneamine typically for Q[7]. The host-guest complexes of Cucurbit[n = 6—8]urils with these guests have been investigated by using NMR techniques and ESMS method. Also, thermoanalysis has been used for exploring relationship of enthalpy and stability of the host-guest complexes.
基金supported by the National Natural Science Foundation of China(Grant No.U22B6004,51974341,51904324)the Fundamental Research Funds for the Central Universities(No.20CX06070A)the Science and Technology Support Plan for Youth Innovation of University in Shandong Province(Grant No.2019KJH002).
文摘Tight oil resources are abundant in the world.It is very important to strengthen the research on the development theory and technology of tight oil reservoirs for ensuring national energy security.Natural gas huff-n-puff can effectively improve the oil recovery of tight oil reservoirs.However,the pore-scale oil production characteristics and the mechanisms of natural gas huff-n-puff in matrix-fracture cores are poorly understood.The influence degree of important factors on oil recovery is not clear and the interactions between factors are rarely considered.In this paper,the oil production characteristics and mechanisms of natural gas huff-n-puff in tight cores with different fracture lengths were quantitatively analyzed by combining nuclear magnetic resonance(NMR)with numerical simulation technology.The influencing factors and their interactions were evaluated by the response surface method(RSM).The results show that tight cores mainly consist of medium pores(0.1–1μm)and small pores(0.01–0.1μm).The fracture mainly increases the proportion of macro-pores(1–10μm)and medium pores.In the natural gas huff-n-puff process,crude oil from macro-pores(1–10μm)and medium pores is mainly developed,and the contribution percentage of crude oil in medium pores to oil recovery is the largest,up to 98.28%.The position of gas–oil contact(GOC)moves deeper as the number of huff-n-puff cycles increases.The contents of CH_(4) and CO_(2) in the oil phase remain at a high level within the GOC,while between the GOC and the component sweep front,the contents of CH_(4) and CO_(2) in the oil phase decrease with the increase in dimensionless distance.The gas component sweep volume is increasing with the increase in fracture length.Moreover,the injected natural gas mainly extracts C_(3)–C_(10) components from crude oil.The reduction law of crude oil viscosity is consistent with the migration laws of CH_(4) components along the path.Compared with soaking time and gas diffusion coefficient,the injection pressure is the most signi
