Rapid generation and control of microporosity, bimodal pore size distribution, and surface area in Davankov-type hyper-cross-linked resins

Abstract

Synthesis of Davankov-type hyper-cross-linked resin beads has been carried out using gel-type and permanently porous poly(divinylbenzene-co-vinylbenzyl chloride) (DVB-VBC) precursor resins without any external electrophile. Of the Lewis acids examined (FeCl3, AlCl3, SnCl4), FeCl3 was by far the most effective catalyst. Rather remarkably in the case of a gel-type 2 mol % DVB-VBC precursor, extensive microporosity was generated within only 15 min of initiating the cross-linking reaction, yielding a surface area (N-2 sorption/BET) of similar to 1200 in which rose steadily to a maximum approaching 2000 m(2) g(-1) in after 18 h. In the case of porous DVB-VBC precursor resins, the presence of discrete pores in the precursor, accompanied by a micropore fraction on hyper-cross-linking, yields resins with a clearly bimodal distribution of pores. Manipulation of the Friedel-Crafts reaction variables and the structure of the precursor resin allows final resin products to be prepared with surface areas in the range similar to 300-2000 m(2) g(-1).