Abstract: Disclosed herein is a process for producing a sheet of a color-developer for a pressure-sensitive recording paper, which process comprises the steps of dissolving an organic color-developer in an organic solvent, dispersing the formed solution into water, thereby forming minute liquid droplets with a diameter of 0.01 to 2 .mu.m, removing the solvent in the liquid droplets by heating while taking care not to cause any coalescence of the droplets and also any unstabilization of the emulsion, thereby forming a slurry comprising the minute granules of the color-developer and applying the slurry on a supporting sheet.

Abstract: Disclosed herein is a catalyst suitable for dehydrocoupling of toluene or xylene, represented by the general formula (I):M.sub.a Tl.sub.b O.sub.c (I),wherein M represents yttrium, zinc or zirconium; a denotes a number in a range of 0.25 to 5, b denotes 1, and c denotes a number necessary for fulfilling the respective average atomic valencies of M and Tl in the oxidation states in which they exist in the composition represented by the formula (I), and a process for dehydrocoupling of toluene or xylene in the presence of the catalyst represented by the general formula (I).

Abstract: Sulfur dioxide can be removed from a combustion exhaust gas and converted to gypsum by first scrubbing a sulfur dioxide-containing combustion exhaust gas with an aqueous alkali sulfite solution to form an alkali bisulfite-containing aqueous solution and then treating, within a closed system, the thus formed aqueous bisulfite solution with a calcium compound. The efficiency of the sulfur dioxide removal can be increased greatly by adding a portion of alkali sulfite aqueous solution circulating in the system to at least a portion of filtrate from the gypsum separation process to precipitate metallic ionic impurities contained in the filtrate in the form of salts and separate these salts by filtration, and then recirculating the filtrate from the salt separation process to the absorption system.