甲烷氧化偶联Ti－La－Li系氧化物催化剂制备方法的研究

考察了用不同来源Ｌｉ（ＬｉＮＯ３和ＬｉＳＯ４）制备的催化剂催化的甲烷氧化偶联（ＯＣＭ）反应的特点，探讨了以ＬｉＮＯ３为锂源制备的催化剂的高温反应失活机理。ＸＲＤ、ＩＲ、ＸＰＳ和ＢＥＴ等方法的研究结果表明，以ＬｉＮＯ３为锂源制备的催化剂具有反应活性高、空速大的特点，而以Ｌｉ２ＳＯ４为锂源制备的催化剂具有Ｃ２选择性高、活性低、空速小等特点。由ＬｉＮＯ３制得的催化剂的失活原因是：在较高的反应温度下由于表面Ｌｉ的流失，使体相晶格中的Ｌｉ向表相扩散进而导致含Ｌｉ活性相ＬａＴｉ１－ｙＬｉｙＯ３－λ的分解（或部分分解），从而减少了体相和表相中氧空位的数量，导致催化剂的活性降低。设计了ＮＨ：（ＳＯ４）２浸渍法来固定表面锂。

STRUCTURE INVESTIGATION OF TI(OBU)4-ALET3 CATALYST BEFORE AND AFTER HEAT-TREATMENT

The catalyst structure of Ti(OBu)4-AlEt3 at different Al/Ti ratios before and after heat aging has been investigated from the data of UV, GC-MS, ESR and C-13 NMR spectra. The complex compounds formed by HTiEt2 and AlEt2(OBu) exist mainly in the catalyst solution, and no -OBu ligands linking with Ti atoms can be found at an Al/Ti ratio of four before heat aging. Many kinds of catalytic species with different size are formed after heat aging the catalyst at 110-degrees-C for 2 h. Dehydrogenation, accompanied by the valence change from Ti3+ to Ti2+, is observed during the aging process of the catalyst.

非晶态TiO_2-SiO_2网络缺陷和Ti配位结构的ESR研究

在SiO_2中掺杂其它原子会导致熔石英SiO_4四面体网络部分破坏,形成缺陷。主要缺陷有非桥氧,E′心和过氧基。非桥氧为仅与一个Si原子(或Ti原子)成单键的O原子。E′心为与三氧配位的Si原子。剩余一个未配对的印杂化电子形成悬键轨道。过氧基则为游离氧被非桥氧俘获,或非桥氧彼此俘获而形成的。这三种缺陷各有一个未配对电子,因而具有

KEL-TI介质的地震波场响应与成像方法研究

To deal with the problems in multi-component converted seismic wave exploration in coal fields, the wave propagating features and imaging methods of multi-component converted waves in coal measure strata are researched in this thesis firstly. The relations between viscoelasticity and anisotropy in coal measure strata are analyzed to build KEL-TI model, and which seismic wave propagating and attenuating features are researched. The disadvantages of converted wave imaging methods based on common converted point gather are analyzed and constant velocity no NMO converted wave imaging method based on common scattering point gather is put forward, according to Huygens-Fresnel principle, which applicabilities in the elastic isotropic, elastic TI and KEL-TI situations are discussed. To different model simulation data, the common scattering point gathers’ and stacked profiles’ features are analyzed. The results show that the method can image compressional waves and converted waves with high precision. Secondly, the resolution enhancing theories and methods of converted wave are researched by Rayleigh wave suppressing, converted wave static correction and poststack inverse-Q filtering. 1) The polarization filter is designed by the instantaneous polarization information of seismic waves, and the Rayleigh wave suppressing method is researched. From the spectrum analysis before and after filtering, it can be derived that the amplitudes are kept relatively. 2) To constant velocity no NMO converted wave imaging method, the static correction method based on common equivalent offset point gather is put forward and tested to the actual converted waves. 3) The relation between equivalent quality factor of converted wave, compressional wave quality factor and the ratio of compressional to shear wave velocity is derived. The compressional wave quality inversion method by first arrivals of none-offset VSP is researched, and which is then transformed to the equivalent quality factor to perform inverse-Q filtering of actual converted waves. The result has shown that the method can recover the high frequency energy of converted waves. At last, the theories and methods researched in this thesis are practiced to the 3D3C seismic exploration in Guqiao coal mine in Huainan and achieve good results.

Epoxidation of cyclohexene on Ti/SiO2 catalysts prepared by chemical grafting TiCl4 on deboronated silica xerogel

Ti/SiO2 (or Ti/de[B]SiO2) catalysts were prepared by grafting deboronated silica xerogel with gaseous TiCl4. Using TBHP as oxidant, the Ti/de[B]SiO2 catalyst shows both catalytic activity and selectivity in epoxidation of cyclohexene better than 80%, and the activity can be comparable with that of Ti-beta. The catalytic activity of Ti/de[B]SiO2 strongly depends on the content of B of support precursor, and the pretreatment temperature of the support. IR studies show that the sites in the deboronated silica xerogel to react with TiCl4 are not only the silanol nests, but also the defect sites produced during the deboronation. (C) 2001 Elsevier Science B.V. All rights reserved.