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81.
82.
研究了1-和2-苯基萘, 1, 1'-和2, 2'-联萘, 2, 2-二羟基-, 2, 2'-二甲氧基和-2, 2'-甲基磺酰氧基-1, 1'-联萘等七种萘衍生物和三氧化硫的磺化反应。1-苯基萘和1, 1'-联萘的磺化先发生在4位上, 第二取代位置为6和7位。2-苯基萘和2, 2'-联萘均首先得到8位磺酸取代物, 进一步磺化得到8, 4'-和8, 8'-二磺酸取代物。2, 2'-二甲氧基-1, 1'-联萘以13:87的比例得到3位和6位磺酸取代物。2, 2'-二甲磺酰氧基-1, 1'-联萘以58:42的比例得到5位和6位磺酸取代物。2, 2'-二羟基-1, 1'-联萘的等摩尔磺化得到比例为35:65的5位和6位磺酸取代物, 和大于6摩尔的SO~3反应则以62:38的比例得到5位和6位磺酸取代物。 相似文献
83.
Le Ngoc Xuyen Hoang Dang Lanh Ho Si Thoang J. V?lter 《Reaction Kinetics and Catalysis Letters》1989,39(2):293-298
Pt–Ni/-Al2O3 catalysts have been prepared and studied in n-hexane dehydrocyclization. The selectivity for benzene and toluene, a chain lengthening product formation was improved by Ni and correlated with its content.
Pt–Ni/-Al2O3 -. Ni . Ni , .相似文献
84.
Eiichi Kitazawa Akira Ogiso Shuji Takahashi Masaaki Kurabayashi Harumitsu Kuwano Tadashi Hata Chihiro Tamura 《Tetrahedron letters》1979,20(13):1117-1120
Two new diterpenelactones named plaunol A () and B () exhibiting anti-Shay ulcer activity were isolated from Thai medicinal plant, . Structure of was determined by X-ray analysis of its -bromobenzoate and structure of was deduced from the results of chemical correlation and the spectral data. 相似文献
85.
Hoang Dang Lanh G. Lietz Ho Si Thoang J. Völter 《Reaction Kinetics and Catalysis Letters》1982,21(4):429-432
The conversion of n-hexane was studied on a Pt-Sn/Al2O3 catalyst, a PtSn alloy and on the corresponding Pt catalysts. The results indicate the same catalytic effect of tin in supported and unsupported catalysts. It is concluded that the role of tin is connected with alloy formation.
- Pt-Sn/Al2O3, PtSn Pt-. . , .相似文献
86.
Heng-dao Quan Hui-e Yang Masanori Tamura Akira Sekiya 《Journal of fluorine chemistry》2004,125(7):1169-1172
A novel fluorination reagent and catalyst, SbF5/PAF (porous aluminum fluoride), was prepared by impregnating SbCl5 into PAF and then treating with anhydrous hydrogen fluoride. The prepared reagent had an excellent catalytic activity in halogen-exchange, and also improved the properties of SbF5, such as hydroscopicity, corrosion, and toxicity. SbF5/PAF was successfully used in organic synthesis as a fluorinating reagent, and a fixed bed catalyst for F/Cl exchange. 相似文献
87.
Simons electrochemical fluorination (ECF) of 1,4-dimethyl-1,4-homopiperazine, methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine was studied. For comparison, ECF of three piperazines with a N-(methoxycarbonylmethyl) group(s) was also studied. ECF of 1,4-dimethyl-1,4-homopiperazine gave a low yield of corresponding perfluoro(1,4-dimethyl-1,4-homopiperazine) together with perfluoro(2,6-diaza-2,6-dimethylheptane) as the major product. Corresponding perfluoro(homopiperazines) with mono- and/or di-(fluorocarbonyldifluoromethyl) groups [CF2C(O)F] at the 1- and/or 4-position were formed in low yields from methyl 4-ethylhomopiperazin-1-ylacetate and 1,4-bis(methoxycarbonylmethyl)-1,4-homopiperazine, respectively. These new seven-membered perfluoro(1,4-dialkyl-1,4-homopiperazines) were accompanied by the formation of mono- and/or di-basic linear perfluoroacid fluorides resulting from the CC bond scission at the 2- and 3-positions of the ring. From mono- and/or di-N-(methoxycarbonylmethyl)-substituted piperazines, corresponding perfluoropeperazines having the acid fluoride group(s) were formed in low yields. 相似文献
88.
Evaluating the acute toxic effects of drugs or toxins is based mainly on studies which require the use of light microscopy. Recently, the effects of such substances on biological membranes, such as the nasal membrane, has been studied using the traditional Ussing chambers, which make it possible to study the transepithelial flux of drugs across membranes and to measure some bioelectrical parameters. A model is described, with which the changes in the membrane permeability, for sodium, potassium and chlorine, can be calculated directly, based on values obtained from the Ussing chamber system. Also, an experiment is described for evaluating the toxic effects of the cholera toxin B subunit, by measuring these changes in isolated rabbit nasal mucosa. 相似文献
89.
Densities and sound velocities of binary mixtures of cyclohexanone, 2-butanone, 1,4-dioxane and 1,2-dimethoxyethane were measured
at 298.15 K and also the densities at 303.15 K. Excess volumes were determined from densities. Isentropic compressibilities
were determined from densities and sound velocities, and excess thermal expansion factors were determined from excess volumes
of two temperatures. Excess isothermal compressibilities and excess isochoric heat capacities were then estimated using excess
isobaric heat capacities previously reported. Excess volumes and excess isentropic and isothermal compressibilities were negative
except for cyclohexanone+1,4-dioxane system.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
90.