**Author details**

*Stability and Applications of Coordination Compounds*

octahedrally coordinated Ti.

of TS-1 will have broad development.

Central Universities (DUT19LK61).

There is no conflict of interest to be declared.

**5. Conclusions**

related research.

**Acknowledgements**

**Conflict of interest**

The industrial catalyst deactivated partly after the 100 t/a pilot plant reaction. The activity decreased from the inlet to the outlet of the pilot plant reactor [41]. The main reason for the deactivation in pilot plant is similar to that in laboratory, which is blocking of pores and covering of active centers by ethers or oligomers. The more oligomers are generated, the more seriously the catalyst deactivates. The loss of a small amount of framework titanium had little influence on the catalytic activity. The deactivated catalysts could be externally regenerated by calcination at 813 K for 6 h and in situ regenerated by washing with dilute H2O2. The in situ regeneration, rather than the external regeneration, can be adopted in industry. When using in situ regeneration with dilute H2O2, a longer washing time is more effective than a higher concentration of H2O2. There is one thing needing to be concerned for in situ regeneration. If the concentration of H2O2 is too high or the washing time is too long, some tetrahedrally coordinated Ti will be leached out and transform to

Great progress has been made in the synthesis of TS-1 and improvement of its catalytic properties. The relative technologies have become increasingly more mature. However, the active center in TS-1 is still controversial (tetrahedrally, pentahedrally, and/or octahedrally coordinated Ti). The contradiction between the cost and catalytic performance of TS-1 has not been resolved completely. Therefore, the synthesis of high-performing, low cost TS-1 needs to be further studied. At present, people attach great importance to environmental protection; thus, the application

This chapter summarized recent work by our group on TS-1, including the tuning of coordination states of Ti, improvement of diffusion properties, and industrial applications of the HPPO route. We hope to provide some references for

The authors acknowledge financial support from the National Key Research and Development Program of China (2016YFB0301704), the National Natural Science Foundation of China (21506021), and the Fundamental Research Funds for the

**156**

Yi Zuo, Min Liu and Xinwen Guo\* State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, Department of Catalysis Chemistry and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian, China

\*Address all correspondence to: guoxw@dlut.edu.cn

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
