The zeolite EMT has been synthesized with 18-crown-6/Al2O3 ratios as low as 0.14, by applying continuous tumbling of the synthesis mixture during the entire aging and crystallization period. The crystalline product contained only two crown ether molecules per unit cell, and the mother liquor was essentially free of crown ether. It was found that the lower the amount of crown ether, the slower the rate of crystallization and the smaller the crystallites of the product, whereas the total product yield remained well above 90% based on aluminum. With lower crown ether content the range of synthesis conditions under which EMT was obtained became increasingly narrower, presumably because of the increasing probability of nucleating of other phases such as cubic faujasite when less 18-crown-6 is present.

The measured isobutane/2-butene alkylation activity and selectivity of La-exchanged hexagonal faujasite (La-EMT) performed in a semi-batch slurry reactor were considerably higher than those of other La-exchanged zeolites like La-FAU, La-MCM-22 and La-Beta.

The alkylation of isobutane with 2-butene on dealuminated hexagonal H EMT and dealuminated cubic faujasite H FAU with Si/Al ratios of 5–6 was studied at 80°C and compared with results obtained for the as-synthesized and calcined parent material with Si/Al ratios of 3.5. In both cases, the dealuminated samples favour an improved profile with respect to the alkylate yield and selectivity after 3 h reaction time, with dealuminated H EMT as the superior system. The alkylate composition consisted of 76% and about 70% C8 paraffins for dealuminated H EMT and dealuminated H FAU, respectively. Within the C8 fractions the three trimethylpentanes (TMP) 2,3,3-, 2,3,4- and 2,2,4-TMP were the dominating product compounds in all tests, whereas a higher content of dimethylhexanes (DMH) was observed for the H FAUs, both dealuminated and parent material. However, among the four trimethylpentanes (2,2,3-, 2,2,4-, 2,3,3- and 2,3,4-TMP) usually the 2,3,3-TMP and 2,3,4-TMP were the main compounds formed, at least for the dealuminated samples. Oligomerization was suppressed by using the dealuminated samples, however, increasing amounts of C8 olefins after about one half of the monitored reaction time was observed for the H FAUs. By contrast, the H EMTs exhibited much less formation of C8 olefins (and on a constant level) even after 300 min reaction time. The deactivated samples showed mainly formation of paraffinic coke.

A mesoprorous MCM-48 is synthesised with an Si : Al ratio of 22, without observing octahedral aluminnium in its as-synthesised form or after template removal by calcination at 540 °C.

The results of the physical and chemical characterisation of the crystalline zeolite phase obtained in the solution growth facility during the EURECA-1 mission are presented. Comparisons of crystal size and morphology of materials obtained in parallel ground experiments and typical optimised gel syntheses show significant, though not marked differences. Two crystalline phases were obtained, the zeolites offretite and sodalite, in both microgravity and flight experiments. Offretite crystals from the ground experiments exhibited near spherical morphology of dimensions less than 0.5 mu M. Equivalent crystals obtained in the flight experiments had developed into thick fed-like crystals of dimensions approximately 2 x 0.6 mu m. Both these results can be contrasted with the typical gel syntheses under the same conditions in which a pure offretite phase is obtained with spherical crystals under 0.5 mu m in dimensions.