Abstract:

The low temperature etherification activity of molecular sieve is poor. Aimed at this shortcoming, using phosphoric acid solution acid treatment catalyst, the samples of before and after processing were characterized by XRD, XRF, BET, NH3-TPD and Py-IR. Results show that phosphoric acid treatment can maintaining catalyst crystal structure, increase the silica alumina mole ratio, wider pore size distribution, reaming effect obviously, acid amount and acid strength reduce moderately, but the number of strong acid site and the Br?nsted acid site increase significantly. The low temperature etherification activity of above catalysts was investigated in a micro fixed bed reactor. Results indicate that phosphoric acid treatment can significantly improve the low temperature etherification activity. The large pore size generated by acid treatment was beneficial to the diffusion of reactants and products and improved the catalytic efficiency. The increase of strong acid ratio and Br?nsted acid sites is the key to improve the low temperature etherification activity, while too high or too low of acid strength unfavorable to the etherification. The sample of 0.5PA has the best etherification activity, the conversion rate of isoamylene was 65.04%, and the selectivity of TAME was 97.55%.

Key words: etherification, low-temperature activity, Hβ, tertamyl methyl ether, phosphoric acid