Reactions methyl chloroformate, photochemical

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. 

Volatile Organic Compound (VOC), means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. This includes any such organic compound other than the following, which have been determined to have negligible photochemical reactivity Methane ethane methylene chloride (dichloro-methane) 1.1.1-trichloroethane (methyl chloroform) l.l.l-trichloro-2.2.2-trifluorethane (CFC-113), furthermore cyclic, branched or linear completely methylated siloxanes acetone and perfluorocarbon compounds. 

Calix[n]arene derivatives with all the methylene bridges monosubstituted by bromine atoms (that will be referred as bromocalixarenes ) have been prepared via radical or photochemical reaction of the corresponding calix[/i]arene methyl ethers with NBS in a chlorinated solvent (usually CCI4, Eq. 4.19).For 11 [27], 27a [28], 27b [29,30], and the methyl-ether derivative of de-tert-butylated calix[4]arene [31], the main product is the all-cis isomer, as corroborated by X-ray crystallography. The photochemical bromination of 27c yields an achiral isomer with bilateral symmetry of the octabromo derivative as the kinetic product, that upon standing in chloroform isomerizes to an equilibrium mixture of isomers [32, 33]. From the equilibrium mixture, a single isomer was isolated via trituration with cold isopropanol [32]. 

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