Phosgene oxide

F. Chemical inactivation using alkalis is effective, whereas chlorinating is ineffective against phosgene oxide. The eyes should be flushed immediately using water or isotonic sodium bicarbonate solution if available. Physical decontamination of the skin using adsorbent powders, e.g., fullers earth, is advised. 

White solid with a chlorine-llke odor. Odor and eye irritation occur below the TLV and are adequate warning properties. Not combustible. Thermal-breakdown products include hydrogen chloride, phosgene, oxides at nitrogen, and chlorine gas. 

Triphosgene (CCl30)2C=0, is a readily available substitute for phosgene. Oxidation. This combination (1) is comparable to DMSO-oxalyl chloride for both small- and large-scale Swern oxidations. 

Crystalline solid m.p. 35-36 "C, b.p. 154--156 C, prepared by oxidizing A,A -dicycIo-hexylthiourea with HgO in carbon disulphide solution, also obtained from cyclohexylamine and phosgene at elevated temperatures. Used as a mild dehydrating agent, especially in the synthesis of p>eptides from amino-acids. Potent skin irritant. 

Chloroform was formerly used in medicine as an anaesthetic. One disadvantage for this purpose is the ready oxidation which chloroform undergoes on exposure to light and air, generating the poisonous phosgene, or carbonyl chloride, COCU- This is counteracted by storing the liquid in dark amber-... 

Chloroform undergoes oxidation to the very poisonous phosgene upon exposure to light and air. Commercial specimens are therefore stored in brown bottles and contain 1-2 per cent, of alcohol the latter converts the toxic phosgene into the harmless substance diethyl carbonate ... 

Chloroacetyl chloride is manufactured by reaction of chloroacetic acid with chlorinating agents such as phosphoms oxychloride, phosphoms trichloride, sulfuryl chloride, or phosgene (42—44). Various catalysts have been used to promote the reaction. Chloroacetyl chloride is also produced by chlorination of acetyl chloride (45—47), the oxidation of 1,1-dichloroethene (48,49), and the addition of chlorine to ketene (50,51). Dichloroacetyl and trichloroacetyl chloride are produced by oxidation of trichloroethylene or tetrachloroethylene, respectively. 

The diacid components for the manufacture of poly(y -phenyleneisophthalamide) and poly(p-phenyleneterephthalamide) are produced by one of two processes. In the first, the diacid chlorides are produced by the oxidation of / -xylene [108-38-3] or -xylene [106-42-3] followed by the reaction of the diacids with phosgene [75-44-5]. In the second, process m- or -xylene reacts with chlorine initiated by ultraviolet light to form the m- or Nhexachloroxylene. This then reacts with the respective aromatic dicarboxyUc acid to form the diacid chloride. 

In the ketone method, the central carbon atom is derived from phosgene (qv). A diarylketone is prepared from phosgene and a tertiary arylamine and then condenses with another mole of a tertiary arylamine (same or different) in the presence of phosphoms oxychloride or zinc chloride. The dye is produced directly without an oxidation step. Thus, ethyl violet [2390-59-2] Cl Basic Violet 4 (15), is prepared from 4,4 -bis(diethylamino)benzophenone with diethylaruline in the presence of phosphoms oxychloride. This reaction is very useful for the preparation of unsymmetrical dyes. Condensation of 4,4 -bis(dimethylamino)benzophenone [90-94-8] (Michler s ketone) with AJ-phenjl-l-naphthylamine gives the Victoria Blue B [2580-56-5] Cl Basic Blue 26, which is used for coloring paper and producing ballpoint pen pastes and inks. 

Zirconium tetrachloride, ZrCl, is prepared by a variety of anhydrous chlorination procedures. The reaction of chlorine or hydrogen chloride with zirconium metal above 300°C, or phosgene or carbon tetrachloride on zirconium oxide above 450°C, or chlorine on an intimate mixture of zirconium oxide and carbon above 700°C are commonly used. 

Chloroform slowly decomposes on prolonged exposure to sunlight in the presence or absence of air and in the dark in the presence of air. The products of oxidative breakdown include phosgene, hydrogen chloride, chlorine, carbon dioxide, and water. At 290°C, chloroform vapor is not attacked by oxygen. In contact with iron and water hydrogen peroxide is also produced, probably by the following reaction sequence (2) ... 

Carbon tetrachloride [56-23-5] (tetrachloromethane), CCl, at ordinary temperature and pressure is a heavy, colorless Hquid with a characteristic nonirritant odor it is nonflammable. Carbon tetrachloride contains 92 wt % chlorine. When in contact with a flame or very hot surface, the vapor decomposes to give toxic products, such as phosgene. It is the most toxic of the chloromethanes and the most unstable upon thermal oxidation. The commercial product frequendy contains added stabilizers. Carbon tetrachloride is miscible with many common organic Hquids and is a powerhil solvent for asphalt, benzyl resin (polymerized benzyl chloride), bitumens, chlorinated mbber, ethylceUulose, fats, gums, rosin, and waxes. 

Phosphoms oxychloride reacts with ethylene oxide in the presence of aluminum chloride to give tris-2-chloroethyl phosphate, a valuable plasticizer (75). Phosgene reacts with ethylene oxide and other alkylene oxides to form esters of chlorocarbonic acid (76) (see Carbonic and carbonochloridic esters). 

FIG. 23-3 Temperature and composition profiles, a) Oxidation of SOp with intercooling and two cold shots, (h) Phosgene from GO and Gfi, activated carbon in 2-in tubes, water cooled, (c) Gumene from benzene and propylene, phosphoric acid on < uartz, with four quench zones, 260°G. (d) Mild thermal cracking of a heavy oil in a tubular furnace, hack pressure of 250 psig and sever heat fluxes, Btu/(fr-h), T in °F. (e) Vertical ammonia svi,ithesizer at 300 atm, with five cold shots and an internal exchanger. (/) Vertical methanol svi,ithesizer at 300 atm, Gr O -ZnO catalyst, with six cold shots totaling 10 to 20 percent of the fresh feed. To convert psi to kPa, multiply by 6.895 atm to kPa, multiply by 101.3. 

Liquid aliphatic halides are obtained alcohol-free by distillation from phosphorus pentoxide. They are stored in dark bottles to prevent oxidation and, in some cases, the formation of phosgene. 

Tlie respiratory system is tlie main target organ for vapour, gas or mist. Readily-soluble cheirticals, e.g. chlorine or phosgene, attack the upper respiratory tract less soluble gases, e.g. oxides of nitrogen, penetrate more deeply into the conducting airways and, in some cases, may cause pulmonary oedema, often after a time delay. 

Hazard code Larger letter size indicates greater hazard. For example, high hazard materials (R) include phosgene, carbon disulfide, ethylene oxide, etc. Moderate hazard materials (E) include toluene, sulfuric acid, etc. Low hazard materials (J) include soda ash, alum, etc. 

Dichlorocarbene, generated in a variety of ways, was shown to deoxygenate pyridine iV-oxide, being itself oxidized to phosgene. 

A new route to ethylene glycol from ethylene oxide via the intermediate formation of ethylene carbonate has recently been developed by Texaco. Ethylene carbonate may be formed by the reaction of carbon monoxide, ethylene oxide, and oxygen. Alternatively, it could be obtained by the reaction of phosgene and methanol. 

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