Prepn. of zeolites for use as catalysts - from silicates, aluminates and polymeric cations

摘要

Prepn. of crystalline aluminosilicate zeolites from aq. mixts contg. sources of silicate, aluminate and cations in amts. at least equiv. to the Al in the mixt. is carried out using polymeric cations. The polymeric cations can be "ionenes" (contg. positively charged N atoms in the main chain) or "ionomers" (contg. positively charged N atoms in side chains), and are used in an amt. such that the negative charge on 1-100% (pref. 10-90, esp. 40-70%) of the AlO4 tetrahedra in the zeolite is balanced by the positively charge N atoms of the polymers. The process can be used to prepare various known type of zeolite (e.g. mordenite and ZSM-12) and also a novel chabazite-free gmelinite with a cyclohexane absorption capacity of 5-8 wt.%. The latter can be used as a catalyst for cracking, isomerisation and hydrocracking operations. Prefd. ionenes are obtd. by reacting a 3-20C alpha, w-dihalide (esp. dibromide) with a di-tert. alkylenediamine, 1,4-diazabicyclo 2,2,2 octane (Dabco), tetramethylbenzidine, 1,2-bis(4-pyridyl)ethylene or 3,4-bipyridyl. Prefd ionomers include polyvinylpyridinium salts and the reaction prod. of poly(epichlorohydrin) with trimethylamine.