Abstract: Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a chromium oxide catalyst in a reactor whose catalyst-contacting part is lined with one of lining materials represented by the following general formula (I):M.sub.a X.sub.b (I)wherein M can be boron, aluminum, silicon, titanium, zirconium or chromium, X denotes oxygen, nitrogen or carbon, a is an integer of 1-2 and b stands for an integer of 1-3 or with a mixture of at least two of the lining materials. The above process and reactor are effective in maintaining the activity of the catalyst.

Abstract: Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a chromium oxide catalyst in a reactor whose catalyst-contacting part is lined with one of lining materials represented by the following general formula(I):M.sub.a X.sub.b (I)wherein M means boron, aluminum, silicon, titanium, zirconium or chromium, X denotes oxygen, nitrogen or carbon, a is an integer of 1-2 and b stands for an integer of 1-3 or with a mixture of at least two of the lining materials. The above process and reactor are effective in maintaining the activity of the catalyst.

Abstract: Chlorine is produced by reacting hydrogen chloride and oxygen in the presence of a chromium oxide catalyst in a reactor whose catalyst-contacting part is lined with one of lining materials represented by the following general formula (I):M.sub.a X.sub.b (I)wherein M means boron, aluminum, silicon, titanium, zirconium or chromium, X denotes oxygen, nitrogen or carbon, a is an integer of 1-2 and b stands for an integer of 1-3 or with a mixture of at least two of the lining materials. The above process and reactor are effective in maintaining the activity of the catalyst.

Abstract: Hexamethylene diisocyanate (HDI) is prepared by introducing a hexamethylenediamine (HDA) solution and an equivalent amount or more of hydrogen chloride gas simultaneously into a turbulent zone in the vicinity of an agitating blade in an inert organic solvent held under agitation within a tank-shaped reactor and allowing them to undergo a successive salt-forming reaction so as to obtain a high-concentration slurry of hexamethylenediamine hydrochloride (HDA.multidot.HCl) and then reacting the slurry with phosgene. The phosgenation is effected by charging an HDA.multidot.HCl slurry of a high concentration, such as that obtained by the above process, into a tank-shaped reactor held under a pressure above the atmosphere pressure but below 5 kg/cm.sup.2 G and controlling the amount of phosgene, which is to be blown into the reactor, at a level 1-18 molar times per hour the total amount of HDA.multidot.HCl and HDI in the reaction mixture.

Abstract: An improved process is provided for the production of chlorine. In a fluidized-bed reactor having a specific equivalent diameter and made of a material with a particular iron content, hydrogen chloride and oxygen are reacted in particular gas volumes and at specific molar ratio, superficial velocity, temperature and pressure in the presence of a catalyst composed principally of a chromium oxide and having a specific particle size distribution. The catalyst is filled in a specific amount in terms of catalyst layer height at rest. The catalyst can retain its high activity.

Abstract: Chlorine is produced by oxidizing byproduced hydrogen chloride. An offgas containing hydrogen chloride as a byproduct is reacted with oxygen at 300.degree.-500.degree. C. in the presence of a catalyst which contains chromic oxide (Cr.sub.2 O.sub.3) as a principal component. The resulting gas is cooled rapidly and then washed with water to recover vaporized chromium. The hydrogen chloride is then absorbed in water to recover it as an aqueous hydrochloric acid solution. The still remaining portion of the resultant gas is washed with sulfuric acid to remove water from the same, followed by compression and cooling. The resulting liquefied chlorine is separated. The still remaining gas composed principally of oxygen is thereafter returned to the oxidation step.

Abstract: A two-stage continuous preparation process for organic isocyanates uses a primary amine which is reacted with stoichiometrically excess phosgene at a gauge pressure of 10 Kg/cm.sup.2 or lower and a temperature of 60.degree.-100.degree. C. in an inert organic solvent. Then, the resultant reaction mixture is maintained at a gauge pressure of 10 Kg/cm.sup.2 or lower and a temperature of 120.degree.-160.degree. C. until the reaction is completed.