Abstract: A roller is provided with at least one thermocouple for measuring the temperature of a product or sheet. The roller comprises a hollow cylindrical body whose outer surface cooperates by contact with the sheet. The thermocouple removably extends through a guide tube which extends inside the roller and is carried by supports. The end of the guide tube through which the hot junction of the thermocouple extends is fixed in a position perpendicular to the wall of cylindrical body. This end of the guide tube opens onto a blind hole provided in the wall of the cylindrical body where the hot junction of the thermocouple is received. Application in the measurement of the temperature of the sheet of an annealing furnace of a continuous treatment process.

Abstract: The invention relates to a process for the preparation of acetic anhydride, characterized in that a gas containing essentially CO, at a pressure of at least 1 MPa, is reacted with methyl formate in the presence ofa) a rhodium-based catalyst,b) two iodine-containing promoters of different kind, successively ionic and covalent, andc) an N-substituted cyclic amide as solvent.