Chloroformates chlorinated methyl

The various chlorinated methyl chloroformates are identified by the diverse manners in which they react with alkali. The method described dates from Hentschel in 1887 and is still used to-day. ... 

As the other chlorinated methyl chloroformates when they react with alkaline solutions form no formaldehyde, this method may be used for the identification of the monochloro derivative even in the presence of di- and tri- methyl chloroformates. 

Derivation (1) By chlorinating methyl formate, (2) by chlorinating methyl chloroformate. In both methods, the mixture of chloro derivatives is then separated by fractionation. 

Chlorination of various hydrocarbon feedstocks produces many usehil chlorinated solvents, intermediates, and chemical products. The chlorinated derivatives provide a primary method of upgrading the value of industrial chlorine. The principal chlorinated hydrocarbons produced industrially include chloromethane (methyl chloride), dichloromethane (methylene chloride), trichloromethane (chloroform), tetrachloromethane (carbon tetrachloride), chloroethene (vinyl chloride monomer, VCM), 1,1-dichloroethene (vinylidene chloride), 1,1,2-trichloroethene (trichloroethylene), 1,1,2,2-tetrachloroethene (perchloroethylene), mono- and dichloroben2enes, 1,1,1-trichloroethane (methyl chloroform), 1,1,2-trichloroethane, and 1,2-dichloroethane (ethylene dichloride [540-59-0], EDC). 

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. 

Trichloroethane [71-55-6] methyl chloroform, CH CCl, is a colorless, non-flammable Hquid with a characteristic ethereal odor. It is miscible with other chlorinated solvents and soluble in common organic solvents. The compound was first prepared by Regnault about 1840. 

Although this reaction can be carried out at higher temperatures, the yields are reduced, probably owing to loss of the volatile methyl chloroformate, b.p. 71°, and/or decomposition of the product. For example, the yields of trichloromethyl chloroformate are ca. 75% and 55% when the chlorination is carried out at 50-55° and 85-90°, respectively. 

The chlorination of methyl chloroformate in sunlight was first reported by Hentschel, but without a detailed description of either the procedure or the results. The first step of the present procedure for the preparation of trichloromethyl chloroformate utilizes an ultraviolet light source and affords a simple and reproducible way to obtain this reagent. Although trichloromethyl chloroformate may also be synthesized by photochemical chlorination of methyl formate,the volatility of methyl formate causes losses during the reaction and increases the hazard of forming an explosive mixture of its vapor and chlorine gas. The preparation of trichloromethyl chloroformate by chlorination of methyl chloroformate in the dark with diacetyl peroxide as initiator has been reported. However, the procedure consists of several steps, and the overall yield is rather low. 

Toxaphene, see Chlorinated camphene Tributyl phosphate 1,1,1 -Trichloroethane, see Methyl chloroform 10.7 20.25 0.020 0.3... 

Many substances react in the gas phase rather than in solution. An important example is the process thought to deplete the ozone layer the reaction between gaseous ozone, O3, and chlorine radicals, high up in the stratosphere. Ultimately, the chlorine derives from volatile halocarbon compounds, such as die refrigerant Freon-12 or the methyl chloroform thinner in correction fluid. 

V-Deprotection of aminomethylenemalonate derivatives of 2-deoxyglu-copyranose (40, R = H, R1 = OMe, and R = OH, R1 = H,R2 = Ac, R3 = Et) by treatment with bromine or chlorine in chloroform afforded methyl 3,4,6-tri-0-acetyl-2-amino-2-deoxy-j3-D-glucopyranoside hydro-... 

Alkanes pentane, hexane, heptane, cyclohexane Chlorinated solvents chloroform, dichloromethane, 1,2-dichloroethane Ethers diethyl ether, methyl-t-butyl ether, diisopropyl ether Esters ethyl acetate, butyl acetate Long-chain alcohols butanol, octanol Aromatics benzene, toluene, xylene Alkanes pentane, hexane, heptane, cyclohexane Diethyl ether... 

Hudson et a/.151,152 have concluded that the bimolecular solvolysis of ethyl chloroformate involves heterolysis of the carbon-chlorine bond and not heterolysis of the carbon-oxygen bond. Their data shows that the hydrolysis of ethyl chloroformate is a second-order reaction in water/acetone mixtures, methyl chloroformate reacting about 2.2 times as fast in 65% water/acetone at 50°C. Hydroxide ion accelerates the reaction (3.1 x 107 in 18% water/ acetone and 3.4 x 108 in 85% water/acetone) and catalysis by hydroxide ion was observed with pure water as solvent by Hall118. There is some disagreement about the value for the hydrolysis rate coefficient for ethyl chloroformate in water and in other solvents (Table 21). To date, the data of Queen153 (for pure water), Kivinen92 (for ethanol) and Liemiu101 (for methanol) must be considered the most accurate. 

Clay den et al. [115] have reported the synthesis of spirocyclic p-lactams 176 (Scheme 41) by exo-cyclization of lithiated pyridine and quinoline carboxamides. The reaction of isonicotinamide or chlorinated isonicotinamide 175 with LDA at -40°C with addition of methyl chloroformate led to the formation of spirocyclic p-lactams 176 in good yields. Benzyl chloroformate, benzoyl chloride, methyl triflate can also be used as the effective acylating agents. In these type of reactions, lithiation of /V-benzyl pyridine and quinoline carboxamides to nitrogen provided... 

Methylene chloride and chloroform are produced by chlorinating methyl chloride. Methylamines are produced by catalytically reacting ammonia with methanol. Methyl chloride is used in the production of silicones and tetramethyl lead. Methylene... 

Another preparatively valuable multiple chlorination is the photochemical perchlorination of methyl chloroformate, which leads to diphosgene ... 

The process can accept a wide range of low-cost feedstocks, such as ethylene, chlorinated C2 hydrocarbons, and by-product streams from VCM chloromethanes, methyl chloroform, and EDC plants. The product ratio of trichloroethylene to perchloroethylene can be adjusted over a wide range. 

From Methyl Chloroformate By chlorination of methyl chloroformate, obtained from methyl alcohol and phosgene. 

A small quantity, about 10 ml., of methyl chloroformate is placed in a flask fitted with a tap-funnel, a tube to introduce the phosgene and an exit tube, and after cooling to 0° C. a current of chlorine-free phosgene is bubbled in. Methyl alcohol is added from the tap-funnel, after a time, in volume about one-third of that of the liquid in the flask, this addition being made all at once. The addition of a fresh quantity of methyl alcohol is made when it is obvious that the phosgene is no longer being absorbed. The total quantity of methanol used should preferably not exceed 150 ml. 

Because of its strongly irritant properties, it has been used in insecticidal preparations " Zyklon A, which is a mixture of 90% of methyl cyanoformate and 10% of methyl chloroformate, and Zyklon B, a mixture of liquid hydrocyanic acid and irritant chlorinated and brominated compounds. ... 

These compounds were prepared by Hentschel in 1887 by the action of chlorine on methyl chloroformate. 

According to Grignard, the chlorination must commence in the gaseous phase, and so the methyl chloroformate is first heated in such a way as to produce a slight pressure, then the lamps switched on and the chlorine then introduced at such a rate as to prevent the reaction from being violent. The product may be rectified as described in the preceding method. 

As the proportion of methyl chloride grows, it competes with the methane for the available chlorine. By the time the concentration of methyl chloride exceeds that of methane, chlorine is more likely to attack methyl chloride than methane, and the second stage of chlorination becomes more important than the first. A large amount of methylene chloride is formed, which in a similar way is chlorinated to chloroform and this, in turn, is chlorinated to carbon tetrachloride. When we finally work up the reaction product, we find that it is a mixture of all four chlorinated methanes together with some unreacted methane. 

I wish to take this opportunity to report that chloropicrin, whose formation by the distillation of nitric acid, alcohol and salt I reported earlier Am, 101, 212), can be prepared also (1) when molten or solid chloral is distilled with concentrated nitric acid or with a mixture of nitric and sulfuric acids, and (2) when a mixture of wood alcohol and sulfuric acid, poured over a mixture of saltpeter and salt, is distilled. Both methods characterize chloropicrin as a methyl derivative according to the latter, it appears to be methyl chloride whose hydrogen is substituted by chlorine and NO2 according to the first, as nitrated chloroform or as the nitrit of triply chlorinated methyl. 

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