Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to ...Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to develop an eco‐friendly and nuisanceless OSDA for zeolite synthesis.Herein,choline is employed as a non‐toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8.The prepared Y zeolite samples exhibited outstanding(hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio.The XRF,SEM,29Si‐NMR and 13Na+results suggested that choline plays a structure‐directing role in the synthesis of Y zeolite,while the feed molar fraction of Na+is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology.展开更多
A new coordination compound of Zn(NH3)3(AFT)2(1,ZnC6H13N17O2,AFT =4-amino-3-(5-tetrazolate)-furazan)was synthesized and characterized by elemental analysis and FT-IR spectrum.Its crystal structure was determined by X-...A new coordination compound of Zn(NH3)3(AFT)2(1,ZnC6H13N17O2,AFT =4-amino-3-(5-tetrazolate)-furazan)was synthesized and characterized by elemental analysis and FT-IR spectrum.Its crystal structure was determined by X-ray single-crystal diffraction.This crystal belongs to the orthorhombic system,space group Pnma with a = 18.680(3),b = 6.9438(11),c =12.268(2)A,μ= 1.592 mm-1,V= 1591.3(4)A3,M,= 420.72,Dc=1.756 g·cm^-3,Z= 4,F(000)= 860,the final R = 0.0480 and wR = 0.1262 for the observed reflections with I>2σ(Ⅰ).The zinc(Ⅱ)ion is five-coordinated by N atoms from two AFT"ligands and three NH3 molecules.The thermal decomposition mechanism of compound 1 was tested by differential scanning calorimetry(DSC)and thermogravimetry-derivative thermogravimetry(TG-DTG)methods.The DSC curve exhibits two endothermic and one exothermic processes.In addition,the non-isothermal kinetics parameters were calculated by using the Kissinger s method and Ozawa-Doyle's method.Besides,the entropy of activation(ΔS≠),enthalpy of activation(ΔH≠),free energy of activation(ΔG≠)and impact sensitivity(IS)was also obtained.展开更多
The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 ...The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.展开更多
Five energetic compounds, 3,3-bis（tetrazol-5-yl）-4,4-azofurazan （DTZAF）, 3-nitro-4-（tetrazol-5-yl）furazan （NTZF）, hydrazinium 3-amino-4-（tetrazol-5-yl）furazan （HATZF）, triaminoguanidinium 3-amino-4-（tetra...Five energetic compounds, 3,3-bis（tetrazol-5-yl）-4,4-azofurazan （DTZAF）, 3-nitro-4-（tetrazol-5-yl）furazan （NTZF）, hydrazinium 3-amino-4-（tetrazol-5-yl）furazan （HATZF）, triaminoguanidinium 3-amino-4-（tetrazol- 5-yl）furazan （TAGATZF） and guanylureaium 3-amino-4-（tetrazol-5-yl）furazan （MATZF）, were prepared using 3-amino-4-（tetrazol-5-yl）furazan （ATZF） as starting material and their structures were characterized by FT-IR, IH NMR, 13C NMR and elemental analysis. The properties of NTZF were estimated： density is 1.67 g/cm3, enthalpy of formation ＋415.41 kJ/mol and detonation velocity 8257.83 m/s. The main thermal properties of four compounds, DTZAF, HATZF, TAGATZF and MATZF, were analyzed by TG and DSC techniques and the results showed that their melting points are 251.9, 159.7, 205.4 and 211.4 ℃, respectively, and their first decomposition temperatures are 256.7, 258.6, 231.7 and 268.6℃, respectively. The fact that their decomposition temperatures were over 230 ℃ showed that they exhibit better thermal stability.展开更多
The clayish crushed stone was used for making aerated concrete. Through studying hydro-thermal synthesis reaction, mix ratio, gas-forming and performance analysis, Grade-B05 and Grade-B06 aerated concrete were prepare...The clayish crushed stone was used for making aerated concrete. Through studying hydro-thermal synthesis reaction, mix ratio, gas-forming and performance analysis, Grade-B05 and Grade-B06 aerated concrete were prepared successfully. The proper mix ratio and key processing parameters were achieved. The microstructure of aerated concrete with crush stone was analyzed by means of XRD and SEM. The experimental results indicate that the hydration products are poorly crystalline C- S- H （ B ）, tobermorite and hydrogarnet. No componeat of clay was found. Unreacted SiO2 cart be in existence, and the structure system of aerated concrete is homogencous and dense.展开更多
The behaviour of cyanothioacetamide 1 and the acetonitrile derivatives 6 and 10, respectively, towards the nitrones 2a-i induced by free solar thermal energy is reported. Structures and reaction mechanisms are also di...The behaviour of cyanothioacetamide 1 and the acetonitrile derivatives 6 and 10, respectively, towards the nitrones 2a-i induced by free solar thermal energy is reported. Structures and reaction mechanisms are also discussed.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.21802136)~~
文摘Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to develop an eco‐friendly and nuisanceless OSDA for zeolite synthesis.Herein,choline is employed as a non‐toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8.The prepared Y zeolite samples exhibited outstanding(hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio.The XRF,SEM,29Si‐NMR and 13Na+results suggested that choline plays a structure‐directing role in the synthesis of Y zeolite,while the feed molar fraction of Na+is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology.
基金financial assistance from the National Natural Science Foundation of China(No.21241003)the Natural Science Basic Research of Shaanxi Province(No.2018JM2061)the Northwest University Graduate Innovation and Creativity Funds(No.YZZ17145)
文摘A new coordination compound of Zn(NH3)3(AFT)2(1,ZnC6H13N17O2,AFT =4-amino-3-(5-tetrazolate)-furazan)was synthesized and characterized by elemental analysis and FT-IR spectrum.Its crystal structure was determined by X-ray single-crystal diffraction.This crystal belongs to the orthorhombic system,space group Pnma with a = 18.680(3),b = 6.9438(11),c =12.268(2)A,μ= 1.592 mm-1,V= 1591.3(4)A3,M,= 420.72,Dc=1.756 g·cm^-3,Z= 4,F(000)= 860,the final R = 0.0480 and wR = 0.1262 for the observed reflections with I>2σ(Ⅰ).The zinc(Ⅱ)ion is five-coordinated by N atoms from two AFT"ligands and three NH3 molecules.The thermal decomposition mechanism of compound 1 was tested by differential scanning calorimetry(DSC)and thermogravimetry-derivative thermogravimetry(TG-DTG)methods.The DSC curve exhibits two endothermic and one exothermic processes.In addition,the non-isothermal kinetics parameters were calculated by using the Kissinger s method and Ozawa-Doyle's method.Besides,the entropy of activation(ΔS≠),enthalpy of activation(ΔH≠),free energy of activation(ΔG≠)and impact sensitivity(IS)was also obtained.
基金This work was supported by the National Naturel Science Foundation of China(No.600740i9).
文摘The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.
文摘Five energetic compounds, 3,3-bis（tetrazol-5-yl）-4,4-azofurazan （DTZAF）, 3-nitro-4-（tetrazol-5-yl）furazan （NTZF）, hydrazinium 3-amino-4-（tetrazol-5-yl）furazan （HATZF）, triaminoguanidinium 3-amino-4-（tetrazol- 5-yl）furazan （TAGATZF） and guanylureaium 3-amino-4-（tetrazol-5-yl）furazan （MATZF）, were prepared using 3-amino-4-（tetrazol-5-yl）furazan （ATZF） as starting material and their structures were characterized by FT-IR, IH NMR, 13C NMR and elemental analysis. The properties of NTZF were estimated： density is 1.67 g/cm3, enthalpy of formation ＋415.41 kJ/mol and detonation velocity 8257.83 m/s. The main thermal properties of four compounds, DTZAF, HATZF, TAGATZF and MATZF, were analyzed by TG and DSC techniques and the results showed that their melting points are 251.9, 159.7, 205.4 and 211.4 ℃, respectively, and their first decomposition temperatures are 256.7, 258.6, 231.7 and 268.6℃, respectively. The fact that their decomposition temperatures were over 230 ℃ showed that they exhibit better thermal stability.
文摘The clayish crushed stone was used for making aerated concrete. Through studying hydro-thermal synthesis reaction, mix ratio, gas-forming and performance analysis, Grade-B05 and Grade-B06 aerated concrete were prepared successfully. The proper mix ratio and key processing parameters were achieved. The microstructure of aerated concrete with crush stone was analyzed by means of XRD and SEM. The experimental results indicate that the hydration products are poorly crystalline C- S- H （ B ）, tobermorite and hydrogarnet. No componeat of clay was found. Unreacted SiO2 cart be in existence, and the structure system of aerated concrete is homogencous and dense.
文摘The behaviour of cyanothioacetamide 1 and the acetonitrile derivatives 6 and 10, respectively, towards the nitrones 2a-i induced by free solar thermal energy is reported. Structures and reaction mechanisms are also discussed.
