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作 者:郭新闻[1] 王祥生[1] 李钢[1] 刘民[1] 修景海[1]
机构地区:[1]大连理工大学精细化工国家重点实验室,大连116012
出 处:《石油学报(石油加工)》2002年第2期34-40,共7页Acta Petrolei Sinica(Petroleum Processing Section)
基 金:国家自然科学基金和中国石化总公司联合资助项目 (批准号 2 9792 0 71)
摘 要:以四丙基溴化铵 (TPABr)为模板剂 ,正丁胺为碱源 ,水热条件下合成了钛硅分子筛TS 1。采用IR、XRD、UV Vis、SEM等对其进行了表征 ,并考察了丙烯环氧化性能 ;采用在空气中程序升温焙烧的方式考察了其热稳定性 ;采用XRD、IR、UV Vis光谱详细考察了不同焙烧温度下钛硅沸石中钛的存在环境。结果表明 ,所合成的钛硅沸石与标准方法合成的钛硅沸石相比 ,主要差异在于晶粒尺寸与非骨架钛类型 ,即以TPABr为模板剂合成的晶粒较大 ,且其中的非骨架钛为非锐钛矿型TiO2 。廉价原料合成的TS 1具有较好的热稳定性能。当焙烧温度低于 110 0℃时 ,IR谱图中 96 0cm-1左右代表钛进入骨架的特征峰的强度变化不大 ;UV Vis谱图中代表非骨架钛的特征峰的信号变化也不大。当焙烧温度高于 110 0℃时 ,IR谱图中 96 0cm-1处的峰强度及峰位置发生变化。XRD表明用TPABr为模板剂合成的TS 1中的非骨架钛逐渐转变成金红石型TiO2 ,而以TPAOH为模板剂合成的钛硅沸石中 ,非骨架钛转化成锐钛矿型TiO2 。廉价原料合成的高钛含量的钛硅分子筛在高温下焙烧时 ,非骨架钛也转化成金红石型TiO2 ,但酸处理可以提高其热稳定性能。Titanium silicalite-1 (TS-1) was successfully synthesized in the system of TPABr-n-butylamine in 100 l stainless-steel autoclave. The synthesized materials were characterized by many techniques, such as, IR, XRD, UV-Vis, XRF, Raman spectroscopy, SEM and 27Al MAS NMR. The thermostability of TS-1 synthesized by using TPABr as the template, which is expected to be cheaper raw materials in future use, was investigated. The results showed that, when the calcination temperature was lower than 1100°C, there observed no changes in IR and UV-Vis spectra. But, when the calcination temperature was above 1100°C, the intensity of 960 cm-1 examined by IR and the relative crystallinity by XRD decreased. When the calcination temperature was up to 1300°C, the framework of TS-1 collapsed and converted into α-cristobalite. The epoxidation properties of TS-1 showed that the calcination temperature played an important role on catalytic properties of TS-1. When the calcination temperature was above 900°C, the activity of TS-1 decreased drastically. During the calcination of TS-1, the extra-framework titanium converted into rutile. During the synthesis of TS-1 with TPAOH as the template, the extra-framework existed in the form of anatase, even if calcination temperature was as high as 1300°C, it could not convert into rutile.
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