Abstract: There is disclosed a method of recovering chlorine gas from calcium chloride comprising the steps of introducing calcium chloride into a heat-resistant vessel which is provided with a gas inlet pipe and a gas outlet pipe, heating the calcium chloride up to at least the melting point thereof while introducing an inert gas from the gas inlet pipe into the vessel to produce fused salt of calcium chloride, and heating the interior of the vessel up to at least 1073K and switching a gas to be introduced from the gas inlet pipe from the inert gas to oxygen to allow the fused salt of calcium chloride to react with the oxygen to obtain chlorine gas and calcium oxide, the chlorine gas being subsequently rapidly and continuously discharged from the vessel through the gas outlet pipe.

Abstract: There is disclosed a method of recovering chlorine gas from calcium chloride comprising the steps of introducing calcium chloride into a heat-resistant vessel which is provided with a gas inlet pipe and a gas outlet pipe, heating the calcium chloride up to at least the melting point thereof while introducing an inert gas from the gas inlet pipe into the vessel to produce fused salt of calcium chloride, and heating the interior of the vessel up to at least 1073K and switching a gas to be introduced from the gas inlet pipe from the inert gas to oxygen to allow the fused salt of calcium chloride to react with the oxygen to obtain chlorine gas and calcium oxide, the chlorine gas being subsequently rapidly and continuously discharged from the vessel through the gas outlet pipe.

Abstract: The present invention provides a method of using a silica-supported 12-molybdosilicic acid catalyst consisting of 12-moloybdosilicic acid supported on silica, in which 12-molybdosilicic acid is supported in an amount not smaller than 10 mass % on silica, wherein the reaction system is heated in the presence of the silica-supported 12-molybdosilicic acid catalyst to the operating temperature of the catalyst at a rate not lower than 100° C./min.

Abstract: The present invention provides a silica-supported 12-molybdosilicic acid catalyst comprising a silica carrier and at least 10% by weight, based on the silica amount, of 12-molybdosilicic acid supported on the carrier and a method of producing formaldehyde directly from a mixed gas of methane and oxygen in the presence of the particular catalyst. Formaldehyde can be produced at a high yield in the present invention without requiring a reforming process of methane with water vapor that consumes a large amount of energy. In addition, attentions are also paid to the air pollution and water contamination problems in the present invention.