Study of Dehydrochlorination of 1,1,2‐trichloroethane Over CsCl/Al ₂ O ₃ Catalyst

ABSTRACT Polyvinylidene chloride (PVDC) was one of the essential sealed packaging materials. The desirable production process of vinylidene chloride (VDC), as the polymer monomer of PVDC, urgently needs to be explored because of the shortcomings of the present process. The present investigation was focused on the dehydrochlorination of 1,1,2‐trichloroethane (1,1,2‐TCE, called as TCE here) to VDC over CsCl/Al 2 O 3 . The dehydrochlorination reaction of TCE was carried out in the continuous flow fixed reactor. The effects of content CsCl over CsCl/Al 2 O 3 on the activity of TCE dehydrochlorination were investigated in detail. In addition, the stability and deactivation of 0.6CsCl/Al 2 O 3 in TCE dehydrochlorination were also discussed. The prepared CsCl/Al 2 O 3 catalysts were characterized by XRD, NH 3 ‐TPD, CO 2 ‐TPD, and N 2 adsorption‐desorption. The results showed that the conversion of TCE dehydrochlorination was improved up to a maximum with the increment of CsCl loading over CsCl/Al 2 O 3 to 1.0% and then appreciably decreased with further increase of CsCl loading. VDC selectivity was also enhanced with the increase of CsCl loading to 0.6%, and then it was almost leveled off at higher loading. The CsCl loading on Al 2 O 3 greatly reduced the acid sites and produced new base sites. Therefore, it could be considered that the new base sites over CsCl/Al 2 O 3 should be responsible for the improvement of TCE dehydrochlorination activity, although the catalyst activity could not be well correlated with the number of base sites on CsCl/Al 2 O 3 . The deactivation of 0.6CsCl/Al 2 O 3 at the initial reaction stage should be attributed to the coverage of base sites by the polymerization macromolecules.