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Development of Solid Superbase by Controlled Oxygen Anion Generation

通过受控氧负离子发生开发固体超级碱

基本信息

批准号：
12650778
负责人：
YAMAGUCHI Tsutomu
金额：
$ 2.11万
依托单位：
Ehime University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650778/
关键词：
solid base alkali metal salts olefin isomerization green chemistry

项目摘要

1. A highly basic solid catalyst was obtained by dispersing metal salts over supports at the surface density of 10 - 15 x 10^<18> K^+ ions m^<-2> and activating them at proper temperature in an inert atmosphere. Metal salts can be the nitrate or carbonate of group 1 elements. Effective supports were alumina and zirconia; silica and titania are ineffective.2. The catalyst exhibited high activity in the isomerizations of cis-but-2-ene, 3-methyl-but-l-ene, propa-1,2-diene and α-pinene, and the isomerization/dehydrogenation of cyclohexadiene to benzene, cyclohexene and hydrogen, and of limonene to p-cymene3. From TPD and IR/Raman spectroscopy, it was found that mounted metal salts exist as both an agglomerated phase when the surface density is high and an ion-separated phase when the surface density is low. The former decomposes at the temperature close to its own decomposition temperature, while the latter decomposes far below the decomposition temperature and was attributed to the anion decomposition that may be free from its counter cation.4. The generation of basic property closely relates to the anion decomposition. NO_3^- decomposes to NO_2 + O^- and CO_2 decomposes to CO_2 + O^<2->. It is suspected that the liberated oxygen anion(s) constitutes basic centers.5. It is speculated that liberated oxygen anions can be discriminated from the anions of metal oxide supports in case of alumina and zirconia, while can not on titania support. Metal salts can only exist as agglomerated phase on silica support that was confirmed by XRD. Effectiveness of support could be the difference of the discrimination ability of liberated oxygen anions from those of supports. The loss of basicity at elevated temperatures could be attributed to the leveling of both oxygen anions.

1.通过将金属盐分散在表面密度为10 - 15 × 10 ↑ [2] K ↑ [2 +]/m ↑ [2]的载体上，<18><-2>并在惰性气氛中在适当温度下活化，得到高碱性固体催化剂。金属盐可以是第1族元素的硝酸盐或碳酸盐。有效的载体是氧化铝和氧化锆;二氧化硅和二氧化钛无效。2.该催化剂对顺式-2-丁烯、3-甲基-1-丁烯、1，2-丙二烯和α-蒎烯的异构化反应，环己二烯异构化/脱氢制苯、环己烯和氢气，柠檬烯异构化/脱氢制对伞花烃等均表现出较高的活性。从TPD和IR/拉曼光谱，它被发现，安装的金属盐同时存在作为一个团聚相时，表面密度高，和一个离子分离相时，表面密度低。前者在接近其自身分解温度的温度下分解，而后者在远低于其分解温度的温度下分解，并归因于可能脱离其抗衡阳离子的阴离子分解.碱性的产生与阴离子的分解密切相关。NO_3^-分解为NO_2 + O^-，CO_2分解为CO_2 + O^-<2->。据推测，释放的氧阴离子构成了碱性中心。推测在氧化铝和氧化锆的情况下，释放的氧阴离子可以与金属氧化物载体的阴离子区分开，而在二氧化钛载体上不能。XRD证实金属盐在二氧化硅载体上只能以团聚相存在。载体的有效性可能是从载体的那些释放的氧阴离子的区别能力的差异。在升高的温度下的碱度的损失可以归因于两种氧阴离子的水平化。