Storage of phosgene

Despite the apparent simplicity of the chemistry, the commercial production of phosgene is carried out by a relatively small number of large chemical companies that have developed the know-how to handle the toxic and corrosive phosgene product. Because of its extreme toxicity, most production is captive for immediate use in downstream processes. There is no on-site storage of phosgene, and the phosgene inventory in downstream processes is minimized. 

The liquid phosgene product is sent directly to the downstream process without intermediate storage. Safety issues with storage of phosgene preclude holdup between process units and the high reliability of the phosgene process avoids the necessity for excess inventory [1]. 

By minimizing inventories of hazardous material, for example through just in time production the consequences of any accident will inevitably be reduced. As discussed above, storage of MIC was responsible for Bhopal and its use could have been avoided by using an alternative synthetic path phosgene, however, is required in both routes. Sometimes it is impossible (with current knowledge) to eliminate the use of a highly... 

Phosgene may be formed when chlorinated hydrocarbons are exposed to ultraviolet radiation in the presence of air [627]. Dichloromethane was found to contain trace quantities of phosgene after storage for a few days in clear glass flasks, despite being protected from exposure to direct sunlight [855]. Trichloromethane decomposes photooxidatively in a similar way to that described for its thermal oxidation (Section 3.3.3), the process differing in the... 

Detailed studies of this kind have been performed in ICI [ICI23,ICI61-ICI64], in which the potential causes, frequencies, and effects of phosgene emissions have been analysed during manufacture, storage, or transportation of the material. It would be inappropriate, however, to describe the detailed results from any one particular installation. 

Storage, condensation and evaporation of phosgene are eliminated, with no... 

There is a lacuna of serious chemical studies upon the reactions of phosgene with the transition metals, even extending to a shortage of published data concerning the rate of attack of phosgene upon the metals most commonly used in its storage, transfer, reactions and transport. 

CHEMICAL PROPERTIES stable under ordinary conditions of use and storage hazardous polymerization will not occur may form small amounts of phosgene due to unusual exposure to light in the presence of air degrades slowly when exposed to air reacts with chemically active metals, strong caustics, and fuming sulfuric acid attacks most plastics and rubber reaction with water can cause appreciable hydrolysis above 110°C (230°F), hydrolysis and oxidation become rapid not an inert solvent FP (NA) LFL/UFL (NA) AT (NA) HC (NA) HF (-195.0 kJ/mol liquid at 25°C). 

However, a phosgene-free route was desired because of environmental hazards and governmental restrictions associated with the production and storage of extremely toxic phosgene (and chlorine used to synthesize it) and the use of chlorinated solvents. An important phosgene-free, so-called melt process, for the DPC synthesis involving transesterification of DPC in the absence of solvents was independently developed by GE, Bayer, Asahi/Chi Mei, and Mitsubishi. 

The main derivative of 1-naphthol is carbaryl, which is produced by the reaction of 1-naphthol with methyl isocyanate. Methyl isocyanate, a toxic liquid boiling at 38 °C, is obtained, among other methods, by the reaction of phosgene with methylamine. Because of its toxicity, it should only be stored for short periods to avoid possible risks during storage (Bhopal accident). 

Phosgene is a very toxic chemical, and storage of it in large quantities poses a serious safety problem. A continuous tubular reactor is developed to make this chemical for immediate consumption. So an inventory of only 70 kg of gaseous phosgene has to be maintained when compared to an inventory of 25,000 kg of the liquid in the storage in the old batch process. Methyl isocyanate (MIC), the infamous chemical that was released at Bhopal, can be generated and immediately converted to the final pesticide in a tubular reactor that will contain a total inventory of less than 10 kg of MIC. 

The industrial use of this synthesis has proved to have terribly detrimental impacts on health and the environment, illustrated most graphically by the 1984 catastrophe in Bhopal, India, which involved the accidental release of the product, methyl isocyanate, and resulting in more than 15,000 fatalities. Further processing of the isocyanate intermediate produced by this method involves transport and storage of large amounts. Moreover, both the major feedstock, phosgene, and the strong acid by-product, hydrochloric acid, are hazardous industrial chemicals. 

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