共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
用水合肼还原的Ru/AC氨合成催化剂的制备 总被引:6,自引:0,他引:6
用RuCl3水溶液浸渍BET比表面积为1020m2/g的椰壳活性炭(AC)载体,制备了钌含量为6%的Ru/AC氨合成催化剂.在添加助剂前,分别用水合肼水溶液、水合肼蒸气和H2还原催化剂,然后分别浸渍Ba(NO3)2和KOH.催化剂中的Ru∶K∶Ba摩尔比为1∶3∶0.3.用N2物理吸附、XPS和CO化学吸附等方法对催化剂进行了表征.结果表明,用不同还原方法制备的催化剂上的钌以不同的化学状态存在,它的活性与其比表面积和金属钌的分散度相关.用水合肼水溶液还原的催化剂S1中的钌在大气气氛下以金属态存在,它的BET比表面积和金属分散度较大,低温低压下催化活性最高.以水合肼蒸气还原的催化剂S2中的钌在大气气氛下以RuO3形态存在,它的BET比表面积和金属分散度小,催化活性最低.用H2还原的催化剂S3中的钌在大气气氛下以RuO2形态存在,其BET比表面积和金属分散度与S1催化剂相当,催化活性也与S1相近. 相似文献
5.
6.
7.
Guang Xin XIA Jian Feng LI Shun An LAI Ai Ming PENG Shu Jun ZHANG Xiao Hui WEI Xin Jian CHEN Jing Shan SHEN Ru Yun JI 《中国化学快报》2005,16(10):1283-1286
A novel series of pyrido[ 1,2-e]purin-4(3H)-one derivatives containing polar substituents on 5'-position were designed and prepared as potential PDE5 inhibitors. This paper reports the synthetic routes, 1H-NMR data, and the PDE5 inhibitory activities of the target compounds. The polar piperazinyl group contained (on 5'-position) compound, 3B2, showed the highest activity among the tested derivatives but less potency than sildenafil 1. 相似文献
8.
9.
10.
以邻甲苯胺、苯胺或乙醇胺和二硫化碳为原料,经与氨水、氯乙酸钠和水合肼反应,合成了N(4)取代氨基硫脲,再与取代水杨醛或2-乙酰基吡啶进行缩合反应,得到6个缩氨基硫脲化合物3a~3f。抗菌实验结果表明:当质量浓度为1 mg/mL时,化合物3d对革兰氏阳性菌—金黄色葡萄球菌和枯草芽孢杆菌有很强的抑菌活性,对革兰氏阴性菌-大肠杆菌有一定的抑菌活性。
相似文献
11.
Summary A new method for the synthesis of steroids has been found which is based on the Michael condensation of 2-(-ketobutyl)-3-vinyl-2-cyclohexanone (V) with 2-methyldihydroresorcinol followed by a double cyclization of the tetraketone (VI). 相似文献
12.
The biological and medicinal properties of sildenafil and its analogues have prompted enormous research aimed at developing synthetic routes to these heterocycles. This review focuses on the chemical properties associated with this system. 相似文献
13.
Y. Nogami K. Fujita K. Ohta K. Nasu H. Shimada C. Shinohara T. Koga 《Journal of inclusion phenomena and macrocyclic chemistry》1996,25(1-3):57-60
An effective synthetic strategy for preparing a new type of cyclooligosaccharide is proposed and along this plan, -, -, and -cycloaltrins, made up from six to eight (14)-linked D-altropyranoses, have been prepared in 36, 52, and 37% overall yields from the corresponding cyclodextrins. 相似文献
14.
A new synthetic method for phosphatidylethanolamine head group was developed via ring-opening of cyclic dioxaphospholane 2 with sodium azide and subsequent hydrogenation.The advantage of this strategy included short reaction steps,readily available materials and good yields. 相似文献
15.
A new approach to the synthesis of benzomorphan derivatives is exemplified by the obtention of 3,6-dimethyl-benzomorphan from the readily available 1-methyl-2,3-benzobicyclo-[3,2,l]octane-4,6-dione. 相似文献
16.
K. Soga S. Hosoda S. Ikeda 《Journal of polymer science. Part A, Polymer chemistry》1979,17(2):517-529
A detailed study has been carried out on the new synthetic reaction of poly(p-xylylene carbonate) from potassium carbonate and p-xylylene dibromide by using a variety of crown ethers as a catalyst, which was recently found by the present authors. Crown ethers having 18-member ring showed the best catalytic property of the various crown ethers, and the reaction was conducted in various solvents at 50–160°C by using 18-crown-6-ether. Both the polymer yield and the molecular weight of the polymer increased in proportion to the amount of potassium carbonate, and they increased rapidly and reached constant values with increasing the concentration of 18-crown-6-ether. They also depended significantly upon the reaction temperature as well as the solvent used. A maximum yield with the highest molecular weight was obtained from the reaction at 100–120°C in diglyme solvent. The spectroscopic analysis of the polymer indicated that all the end groups of the resulting polymer had the structure of benzyl bromide. From these results, a plausible mechanism was proposed for the reaction. Similar reactions were also conducted by using several aliphatic dibromides, Br? (CH2)x? Br, in place of p-xylylene dibromide. The products were strongly dependent of the value of x: polycarbonate was obtained from dibromides with ≧4, and cyclic carbonates from dibromides with ≦3. 相似文献
17.
18.
19.
Novel 2-(5-R-1,3,4-thiadiazol-2-yl)aminothiazolin-4-ones 6a—h and 2-imino-3-(5-R-1,3,4-thiadiazol-2-yl)thiazolidin-4-ones 7a—h were prepared by treating N-(5-R-1,3,4-thiadiazol-2-yl)thioureas 4a—h with chloroacetic acid on various solid supports under microwave irradiation. Tautomeric mixtures of compounds 6a—h and 7a—h were obtained in all cases. In alkaline and neutral media, compounds 6a—h were the major products, while in acid media, 7a—h were the major products. 相似文献
20.