The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as...The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as the application of Satava-Sestak＇s, Ozawa＇s and Kissinger＇s methods, the mechanism and kinetics of thermal dissociation of this inclusion complex were studied. An additional mass loss is found at 170-180℃. The mechanism of thermal dissociation of CD-MCP is dominated by a one-dimensional random nucleation and subsequent growth process （A2/3）. The activation energy Es and the pre-exponential factor AS for the process are 102.14 kJ/mol and 3.63×10^10s^-1, respectively. This ES value shows that there is no strong chemical intere, ctions between β-CD and 1-MC;P,展开更多
The chemical nature of the interaction of starch and dodecylamine （DDA）, which generally act as depressant and collector, respectively, in the reverse flotation of bauxite, was investigated using starch-iodine tests...The chemical nature of the interaction of starch and dodecylamine （DDA）, which generally act as depressant and collector, respectively, in the reverse flotation of bauxite, was investigated using starch-iodine tests. The results obtained from the blue-value measurements for starch＋DDA＋iodine system indicate the formation of the inclusion complex for amylose-DDA system at low DDA concentration （〈2 retool/L）. However, it is less likely for amylopectin-DDA system with short helix. UV-Vis spectra of starch-iodine complexes show that each helix of amylose can accommodate two DDA molecules locating separately at its two ends, and in the helical cavity there is room available for the upcoming iodine. When concentrated DDA is tested, amylose-DDA system exhibits no characteristic starch-iodine color, owing to the presence of a compact coating of DDA molecules on starch via hydroxyl/amine hydrogen bonding. ^1H NMR spectroscopy and surface tension determination help to clarify the interaction mechanism of amylose with DDA.展开更多
The X-ray crystal structure of the inclusion complex of p-tert-butylcalix [4] crown-6 with actonitrile is reported. C54H70O10·3CH3CN, Mr=1002. 3 ,monoclinic, space group C2/c with cell dimensions of a=23.587(7),b...The X-ray crystal structure of the inclusion complex of p-tert-butylcalix [4] crown-6 with actonitrile is reported. C54H70O10·3CH3CN, Mr=1002. 3 ,monoclinic, space group C2/c with cell dimensions of a=23.587(7),b=21.153(6),c=15.608(8) A,β=116.99(3)°,V=6939.2 A3,Z=4, F(000)=2160,Dc=0.959 g/cm3,μ=1.114 cm-1; R=0.088 for 2066 reflections with I>3σ(I).The calixarene subunit exists in a distorted cone conformation. One of the three acetonitrile molecules is located in the intracavity of the calixarene subunit and the other two in the intermolecular channels.展开更多
文摘The inclusion-complex of CD-MCP （β-cyclodextrin （β-CD） including 1-methylcyclopropene （1-MCP）） was prepared and characterized. Basing on programmed-heating procedure and weight-temperature analysis, as well as the application of Satava-Sestak＇s, Ozawa＇s and Kissinger＇s methods, the mechanism and kinetics of thermal dissociation of this inclusion complex were studied. An additional mass loss is found at 170-180℃. The mechanism of thermal dissociation of CD-MCP is dominated by a one-dimensional random nucleation and subsequent growth process （A2/3）. The activation energy Es and the pre-exponential factor AS for the process are 102.14 kJ/mol and 3.63×10^10s^-1, respectively. This ES value shows that there is no strong chemical intere, ctions between β-CD and 1-MC;P,
基金Project(50804055) supported by the National Natural Science Foundation of China
文摘The chemical nature of the interaction of starch and dodecylamine （DDA）, which generally act as depressant and collector, respectively, in the reverse flotation of bauxite, was investigated using starch-iodine tests. The results obtained from the blue-value measurements for starch＋DDA＋iodine system indicate the formation of the inclusion complex for amylose-DDA system at low DDA concentration （〈2 retool/L）. However, it is less likely for amylopectin-DDA system with short helix. UV-Vis spectra of starch-iodine complexes show that each helix of amylose can accommodate two DDA molecules locating separately at its two ends, and in the helical cavity there is room available for the upcoming iodine. When concentrated DDA is tested, amylose-DDA system exhibits no characteristic starch-iodine color, owing to the presence of a compact coating of DDA molecules on starch via hydroxyl/amine hydrogen bonding. ^1H NMR spectroscopy and surface tension determination help to clarify the interaction mechanism of amylose with DDA.
文摘The X-ray crystal structure of the inclusion complex of p-tert-butylcalix [4] crown-6 with actonitrile is reported. C54H70O10·3CH3CN, Mr=1002. 3 ,monoclinic, space group C2/c with cell dimensions of a=23.587(7),b=21.153(6),c=15.608(8) A,β=116.99(3)°,V=6939.2 A3,Z=4, F(000)=2160,Dc=0.959 g/cm3,μ=1.114 cm-1; R=0.088 for 2066 reflections with I>3σ(I).The calixarene subunit exists in a distorted cone conformation. One of the three acetonitrile molecules is located in the intracavity of the calixarene subunit and the other two in the intermolecular channels.
