Abstract: The invention relates to a process for the preparation of 1-(1,3-benzodioxol-5-yl)-1-propanone comprising the step of reacting 3,4-dimethylendioxybenzene with propionic anhydride in the presence of a bulk or supported catalyst, being said catalyst selected from the group of a sulphonated cross-linked divinylbenzene resin, a sulphonated cross-linked divinylbenzene resin partially exchanged with iron, zinc or gallium, a perfluorinated sulphonic resin, and a perfluorinated sulphonic resin partially exchanged with iron, zinc or gallium, wherein said catalyst has an average particle size from 1 ?m to 300 ?m, preferably from 1 ?m to 180 ?m, more preferably from 1 ?m to 100 ?m as measured with DLS (Dynamic light scattering) or a granulometer. The process is advantageously carried out at stoichiometric ratio between the reagents and with a continuous process.

Abstract: A display device is formed from a plurality of modules (2) each including a large number of display elements (21) formed by diffusely radiating hollow bodies. The light sources thereof can be controlled individually in terms of brightness and colour. In this way, it is possible to construct large display devices for halls and stadia.