Crystalline zeolites having a FER framework type wherein the crystallites have a dimension in the c-axis of about 500 nanometres (nm) or less, a method for their preparation and a process for the co-production of acetic acid and dimethyl ether comprising the step of contacting methyl acetate and methanol in the presence of catalysts comprising the crystalline zeolites.

Process for the co-production of acetic acid and dimethyl ether by contacting methyl acetate and methanol in the presence of a catalyst containing a crystalline zeolite having a FER framework type. The zeolite has crystallites having a dimension of about 500 nm or less in the c-axis.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

A loudspeaker device is presented which includes a zeolite material comprising zeolite particles having a silicon to aluminum mass ratio of at least 200. For an increased pore fraction of pores with a diameter in a range between 0.7 micrometer and 30 micrometer shows an increased shift of the resonance frequency down to lower frequencies has been observed.

An organo-template free method for the manufacture of a ferrierite (FER) zeolite and the ferrierite producible by the method. The method comprises (i) forming a reaction gel comprising an aluminium source, sodium and/or potassium hydroxide, and silica sol; and (ii) heating the reaction gel to a temperature and for a duration suitable for the growth of the FER zeolite. The reaction gel does not comprise seed crystals. Moreover the reaction gel does not comprise an organic structure directing agent (OSDA). The ferrierite (FER) zeolite has the following features: a) a SAR of between 11 and 20; b) a BET surface area of between 320 and 380 m.sup.2/g; and c) a micropore volume of between 0.1 and 0.2 cm.sup.3/g.

An organo-template free method for the manufacture of a ferrierite (FER) zeolite and the ferrierite producible by the method. The method comprises (i) forming a reaction gel comprising an aluminium source, sodium and/or potassium hydroxide, and silica sol; and (ii) heating the reaction gel to a temperature and for a duration suitable for the growth of the FER zeolite. The reaction gel does not comprise seed crystals. Moreover the reaction gel does not comprise an organic structure directing agent (OSDA). The ferrierite (FER) zeolite has the following features: a) a SAR of between 11 and 20; b) a BET surface area of between 320 and 380 m.sup.2/g; and c) a micropore volume of between 0.1 and 0.2 cm.sup.3/g.