The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ll...The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ller-Plesset perturbation (MP2) and Hartree-Fock (HF) methods with the 6-31G* and 6-311G* basis sets. The barrier heights for both H2O-assisted and auto-assistance reactions are significantly lower than that of the bare tautomerization reaction from NHMF to N-Formyl Formamide (NFF), implying the importance of the superior catalytic effect of H2O in the monomer of NHMF and important role of HOCH= N-COH for the intramolecular proton transfer.展开更多
Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)...Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.展开更多
A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The p...A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.展开更多
Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This...Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.展开更多
采用气相色谱法建立了丁二烯生产装置尾气中乙腈(ACN)和N,N-二甲基酰胺(DMF)含量的测定方法,对色谱柱初始温度进行了优化,绘制了标准曲线,并用于实际试样的测定。实验结果表明,在色谱柱初始温度为50℃时,丁二烯尾气中各组分具有很好的...采用气相色谱法建立了丁二烯生产装置尾气中乙腈(ACN)和N,N-二甲基酰胺(DMF)含量的测定方法,对色谱柱初始温度进行了优化,绘制了标准曲线,并用于实际试样的测定。实验结果表明,在色谱柱初始温度为50℃时,丁二烯尾气中各组分具有很好的分离效果,以混合标准气体为标样得到的ACN和DMF的标准曲线,线性相关系数大于0.999,在一定的含量范围内,ACN和DMF的加标回收率分别为104.0%~105.4%和89.3%~91.7%,最低检出限分别为1.4 m L/m^3和1.2 m L/m^3,6次重复测定结果的相对标准偏差均小于3.0%,重复性良好。实现了对ACN和DMF的同时测定,提高了分析效率,降低了成本。展开更多
文摘The proton transfer in the isolated, mono and dehydrated forms, isolated dimers of N-Hydroxy Methylen Formamide (NHMF) have been completely investigated in the present study using Density Functional Theory (DFT), M?ller-Plesset perturbation (MP2) and Hartree-Fock (HF) methods with the 6-31G* and 6-311G* basis sets. The barrier heights for both H2O-assisted and auto-assistance reactions are significantly lower than that of the bare tautomerization reaction from NHMF to N-Formyl Formamide (NFF), implying the importance of the superior catalytic effect of H2O in the monomer of NHMF and important role of HOCH= N-COH for the intramolecular proton transfer.
文摘Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.
基金This project supported by the National Key Research and Development Program of China(2016YFC0204300)the National Natural Science Foundation of China(21171055,21333003,21571061)+1 种基金the"Shu Guang"Project of the Shanghai Municipal Education Commission(12SG29)the Commission of Science and Technology of Shanghai Municipality(15DZ1205305)
文摘A series of Ru supported on CeO_2 and Ce_(0.7)Zr_(0.3)O_2(CeZrO) was prepared by incipient-wet impregnation method and investigated in the catalytic wet oxidation of N,N-dimethyl formamide(DMF) in batch reactor. The physicochemical property of the catalysts was characterized by Brunauer-Emmett-Teller(BET), X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR), X-ray photoelectron spectroscopy(XPS) and thermogravimetry(TG). Compared with 3%Ru/CeO_2, 3%Ru/Ce_(0.7)Zr_(0.3)O_2 catalyst exhibits much higher performance for DMF degradation due to the promotion of Ru dispersion and the transfer of active oxygen, and 99% DMF conversion and 97% COD elimination are obtained at 453 K,2.5 MPa oxygen pressure after 5 h. The reaction mechanism of DMF degradation was suggested. The carbonaceous species deposition and oxidation of Ru can be responsible for catalyst deactivation. And the catalyst activity can be recovered by air calcination and H_2 reduction.
基金National Natural Science Foundation of China,Grant/Award Numbers:52272295,52071137,51977071,51802040,21802020Science and Technology Innovation Program of Hunan Province,Grant/Award Numbers:2021RC3066,2021RC3067+1 种基金Natural Science Foundation of Hunan Province,Grant/Award Number:2020JJ3004Fundamental Research Funds for the Central Universities。
文摘Although MXene has attracted great interest in diverse fields,it is susceptible to oxidation in water(H_(2)O)with transition metal ions such as Co^(2+),Fe^(2+),and Cu^(2+),which is pronounced at high temperatures.This impedes the preparation of MXene-based composites and their functional applications.Here,this study revealed that Co^(2+)increases the maximum and average atomic charge of H in H_(2)O to improve the reactivity of H_(2)O,which leads to the fact that Co^(2+)catalyzes the oxidation of Ti_(3)C_(2)T_(x)MXene.Furthermore,the addition of N,Ndimethyl formamide(DMF)reduces theH_(2)Oactivity and improves the oxidation stability of Ti_(3)C_(2)T_(x)in the presence of Co^(2+)via preferentially forming coordination bonds with Co^(2+).This strategy is also effective in enhancing the oxidation tolerance of Ti_(3)C_(2)T_(x)to Fe^(2+)in H_(2)O.Moreover,it is feasible to enhance the oxidation stability of Ti2CTx MXene in H_(2)O with the existence of Co^(2+).By virtue of these,the CoO/Ti_(3)C_(2)T_(x)composite was successfully prepared without obvious Ti_(3)C_(2)T_(x)oxidation,which is desirable to harness the advantages of Ti_(3)C_(2)T_(x)as the complementary component for lithium-ion batteries.This work provides a straightforward paradigm to enhance the oxidation resistance of MXene in H_(2)O in the presence of transition metal ions and at high temperatures,which opens a new vista to use MXene for target applications.
文摘采用气相色谱法建立了丁二烯生产装置尾气中乙腈(ACN)和N,N-二甲基酰胺(DMF)含量的测定方法,对色谱柱初始温度进行了优化,绘制了标准曲线,并用于实际试样的测定。实验结果表明,在色谱柱初始温度为50℃时,丁二烯尾气中各组分具有很好的分离效果,以混合标准气体为标样得到的ACN和DMF的标准曲线,线性相关系数大于0.999,在一定的含量范围内,ACN和DMF的加标回收率分别为104.0%~105.4%和89.3%~91.7%,最低检出限分别为1.4 m L/m^3和1.2 m L/m^3,6次重复测定结果的相对标准偏差均小于3.0%,重复性良好。实现了对ACN和DMF的同时测定,提高了分析效率,降低了成本。
