Conclusions

This paper delves into many aspects of the MTO process mechanism. It looks at the formation of methoxy groups, their reactivity, the formation of the hydrocarbon pool, the steady state MTO operation, the formation of initial hydrocarbons and the methanol to DME mechanism. In this way the paper is more of a review of decades of man-years of work, with some additional work contributed by the authors.

We can conclude the following from this paper:

1. The initial C-C bond formation creates a hydrocarbon pool on the surface of the catalyst that is present and vital to the steady state operation of the MTO process
2. Water/toluene/aliphatics will preferentially react with the methoxy and/or surface acid sites
3. We cannot exclude the direct path route in formation of DME (more research is needed)
4. Initial C-C bond formation can occur from the decomposition of methoxy groups on the surface (it appears no olefins are present as impurities, but one could argue the impurities are still below measurable limits of UV/Vis)