Chloroformate manufacture

CCls CHO. A colourless oily liquid with a pungent odour b.p. 98°C. Manut actured by the action of chlorine on ethanol it is also made by the chlorination of ethanal. When allowed to stand, it changes slowly to a white solid. Addition compounds are formed with water see chloral hydrate), ammonia, sodium hydrogen sulphite, alcohols, and some amines and amides. Oxidized by nitric acid to tri-chloroethanoic acid. Decomposed by alkalis to chloroform and a methanoate a convenient method of obtaining pure CHCI3. It is used for the manufacture of DDT. It is also used as a hypnotic. 

Trichloroethanoic acid, CCI3COOH. A crystalline solid which rapidly absorbs water vapour m.p. 58°C, b.p. 196-5" C. Manufactured by the action of chlorine on ethanoic acid at 160°C in the presence of red phosphorus, sulphur or iodine. It is decomposed into chloroform and carbon dioxide by boiling water. It is a much stronger acid than either the mono- or the dichloro-acids and has been used to extract alkaloids and ascorbic acid from plant and animal tissues. It is a precipitant for proteins and may be used to test for the presence of albumin in urine. The sodium salt is used as a selective weedkiller. 

Chloroform is a potent volatile anaesthetic, but is little used due to its potential hepato-toxicity. It is used principally for the manufacture of chlorofluorohydrocarbon refrigerants ( Arctons and Freons ) and certain polymers. 

CH2C1 CH2C1. Colourless liquid with an odour like that of chloroform b.p. 84 C. It is an excellent solvent for fats and waxes. Was first known as oil of Dutch chemists . Manufactured by the vapour- or liquid-phase reaction of ethene and chlorine in the presence of a catalyst. It reacts with anhydrous ethano-ales to give ethylene glycol diethanoate and with ammonia to give elhylenediamine, these reactions being employed for the manufacture of these chemicals. It burns only with difficulty and is not decomposed by boiling water. 

CH2CI2. A colourless liquid with a chloroform-like odour b.p. 4I°C. Prepared by heating chloroform with zinc, alcohol and hydrochloric acid manufactured by the direct chlorination of methane. Decomposed by water at 200°C to give methanoic and hydrochloric acids. Largely used as a solvent for polar and non-polar substances, particularly for paint removal (30%), dissolving cellulose acetate and degreasing (10%). It is more stable than carbon tetrachloride or chloroform especially towards moisture or alkali. It is somewhat toxic. U.S. production 1981 280000 tonnes. 

HCCI2CHCI2. Colourless toxic liquid with a chloroform-like odour, b.p. 146 C. Manufactured by passing chlorine and ethyne separately into a solution of SbClj in tetra-chloroethane. Reacts with dilute alkalis to give trichloroethene . 

Most of the chlorine produced is used in the manufacture of chlorinated compounds for sanitation, pulp bleaching, disinfectants, and textile processing. Further use is in the manufacture of chlorates, chloroform, carbon tetrachloride, and in the extraction of bromine. 

Chlorine reacts with saturated hydrocarbons either by substitution or by addition to form chlorinated hydrocarbons and HCl. Thus methanol or methane is chlorinated to produce CH Cl, which can be further chlorinated to form methylene chloride, chloroform, and carbon tetrachloride. Reaction of CI2 with unsaturated hydrocarbons results in the destmction of the double or triple bond. This is a very important reaction during the production of ethylene dichloride, which is an intermediate in the manufacture of vinyl chloride ... 

Methylene iodide [75-11-6], CH2I2, also known as diio dome thane, mol wt 267.87, 94.76% I, mp 6.0°C, and bp 181°C, is a very heavy colorless Hquid. It has a density of 3.325 g/mL at 20°C and a refractive index of 1.7538 at 4°C. It darkens in contact with air, moisture, and light. Its solubiHty in water is 1.42 g/100 g H2O at 20°C it is soluble in alcohol, chloroform, ben2ene, and ether. Methylene iodide is prepared by reaction of sodium arsenite and iodoform with sodium hydroxide reaction of iodine, sodium ethoxide, and hydroiodic acid on iodoform the oxidation of iodoacetic acid with potassium persulfate and by reaction of potassium iodide and methylene chloride (124,125). Diiodoform is used for determining the density and refractive index of minerals. It is also used as a starting material in the manufacture of x-ray contrast media and other synthetic pharmaceuticals (qv). 

These solvents include tetrahydrofuran (THF), 1,4-dioxane, chloroform, dichioromethane, and chloroben2ene. The relatively broad solubiHty characteristics of PSF have been key in the development of solution-based hoUow-fiber spinning processes in the manufacture of polysulfone asymmetric membranes (see Hollow-fibermembranes). The solvent Hst for PES and PPSF is short because of the propensity of these polymers to undergo solvent-induced crysta11i2ation in many solvents. When the PES stmcture contains a small proportion of a second bisphenol comonomer, as in the case of RADEL A (Amoco Corp.) polyethersulfone, solution stabiHtyis much improved over that of PES homopolymer. 

Ahyl alcohol undergoes reactions typical of saturated, aUphatic alcohols. Ahyl compounds derived from ahyl alcohol and used industriahy, are widely manufactured by these reactions. For example, reactions of ahyl alcohol with acid anhydrides, esters, and acid chlorides yield ahyl esters, such as diahyl phthalates and ahyl methacrylate reaction with chloroformate yields carbonates, such as diethylene glycol bis(ahyl carbonate) addition of ahyl alcohol to epoxy groups yields products used to produce ahyl glycidyl ether (33,34). 

Pyrrohdinone (2-pyrrohdone, butyrolactam or 2-Pyrol) (27) was first reported in 1889 as a product of the dehydration of 4-aminobutanoic acid (49). The synthesis used for commercial manufacture, ie, condensation of butyrolactone with ammonia at high temperatures, was first described in 1936 (50). Other synthetic routes include carbon monoxide insertion into allylamine (51,52), hydrolytic hydrogenation of succinonitnle (53,54), and hydrogenation of ammoniacal solutions of maleic or succinic acids (55—57). Properties of 2-pyrrohdinone are Hsted in Table 2. 2-Pyrrohdinone is completely miscible with water, lower alcohols, lower ketones, ether, ethyl acetate, chloroform, and benzene. It is soluble to ca 1 wt % in aUphatic hydrocarbons. 

Carbamates derived from chloroformates are used to manufacture pharmaceuticals, including tranquili2ers (58), antihypotensives, and local anesthetics, pesticides, and insecticides (see Carbamic acid). 

Ethyl chloroformate is used in the manufacture of ore flotation agents by reaction with various xanthates (48). 

Diethylene glycol bis (chloroformate) [106-75-2] is the starting material for diethylene glycol bis(allyl carbonate) [142-22-3] CR-39, or Nouryset 200, monomer, used in the manufacture of break-resistant optical lenses, which is obtained by the reaction with aHyl alcohol [107-18-6] (59). Alternatively, it can be obtained from aHyl chloroformate [2937-50-0] and diethylene glycol (60) (see Allylmonomers and polymers). 

Carbonates ate manufactured by essentially the same method as chloroformates except that more alcohol is required in addition to longer reaction times and higher temperatures. The products are neutralized, washed, and distilled. Corrosion-resistant equipment similar to that described for the manufacture of chloroformates is requited. Diaryl carbonates are prepared from phosgene and two equivalents of the sodium phenolates or with phenols and various... 

Ninety-six percent of the EDC produced in the United States is converted to vinyl chloride for the production of poly(vinyl chloride) (PVC) (1) (see Vinyl polymers). Chloroform and carbon tetrachloride are used as chemical intermediates in the manufacture of chlorofluorocarbons (CECs). Methjiene chloride, 1,1,1-trichloroethane, trichloroethylene, and tetrachloroethylene have wide and varied use as solvents. Methyl chloride is used almost exclusively for the manufacture of silicone. Vinylidene chloride is chiefly used to produce poly (vinylidene chloride) copolymers used in household food wraps (see Vinylidene chloride and poly(vinylidene chloride). Chloroben2enes are important chemical intermediates with end use appHcations including disinfectants, thermoplastics, and room deodorants. 

Methanol, heated at 250°C with chloroform or carbon tetrachloride in contact with active carbon, is converted in part to methyl chloride (52). Methyl chloride has been produced from methoxymagnesium chloride, CH OMgCl, a by-product from the manufacture of certain organo—sHicon compounds, by heating over 200°C (53). 

In 1900, the Pennsylvania Salt Manufacturing Co. initiated large-scale production in the United States. The Midland Chemical Co., a subsidiary of The Dow Chemical Company, began to manufacture chloroform by reducing carbon tetrachloride in 1903. Chloroform was one of the first organic chemicals produced on a large scale in the United States. 

Chloroform was used chiefly as an anesthetic and in pharmaceutical preparations immediately prior to World War II. However, these uses have been banned. Annual output in both the United States and the United Kingdom was between 900 and 1350 metric tons. During the war, chloroform production in the United States tripled, largely to meet the requirement for penicillin manufacture. Demand for chloroform continued to increase in the postwar period as its technical appHcations were extended. Consumption continues to increase at a comparatively rapid rate. Chloroform is now used primarily in the manufacture of HCFC-22, monochlorodifluoromethane, a refrigerant, and as a raw material for polytetrafluoroethylene plastics. 

Chloroform can be manufactured from a number of starting materials. Methane, methyl chloride, or methylene chloride can be further chlorinated to chloroform, or carbon tetrachloride can be reduced, ie, hydrodechlorinated, to chloroform. Methane can be oxychlorinated with HCl and oxygen to form a mixture of chlorinated methanes. Many compounds containing either the acetyl (CH CO) or CH2CH(OH) group yield chloroform on reaction with chlorine and alkali or hypochlorite. Methyl chloride chlorination is now the most common commercial method of producing chloroform. Many years ago chloroform was almost exclusively produced from acetone or ethyl alcohol by reaction with chlorine and alkali. 

A good technical grade of carbon tetrachloride contains not more than the following amounts of impurities 1 ppm acidity as HCl, 1 ppm carbon disulfide if manufactured by carbon disulfide chlorination, 20 ppm bromine, 200 ppm water, and 150 ppm chloroform. The residue should not exceed 10 ppm on total evaporation. The product should give no acid reaction with bromophenol blue, and the starch iodine test should indicate the absence of free chlorine. 

Nearly all of the benzyl chloride [100-44-7], henzal chloride [98-87-3], and hen zotrichl oride /P< -(97-i manufactured is converted to other chemical intermediates or products by reactions involving the chlorine substituents of the side chain. Each of the compounds has a single primary use that consumes a large portion of the compound produced. Benzyl chloride is utilized in the manufacture of benzyl butyl phthalate, a vinyl resin plasticizer benzal chloride is hydrolyzed to benzaldehyde hen zotrichl oride is converted to benzoyl chloride. Benzyl chloride is also hydrolyzed to benzyl alcohol, which is used in the photographic industry, in perfumes (as esters), and in peptide synthesis by conversion to benzyl chloroformate [501-53-1] (see Benzyl ALCOHOL AND p-PHENETHYL ALCOHOL CARBONIC AND CARBONOCm ORIDIC ESTERS). 

There now exist alternatives or sufficient quantities of controlled substances for almost all applications of ozone-depleting solvents. Exceptions have been noted for certain laboratory and analytical uses and for manufacture of space shuttle rocket motors. HCFCs have not been adopted on a large scale as alternatives to CFC solvents. In the near term, however, they may be needed as the conventional substances in some limited and unique applications. HCFC-141b is not a good replacement for methyl chloroform (1,1,1 -trichloroethane) because its ODP is three times higher. Alternatives for specific uses of ozone-depleting solvents are briefly described below. 

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