Dimethyl ether, chlorination

Chlorine Monoxide, Dimethyl Ether, Chlorine Dioxide and Sulfur Dioxide.—The radial distribution curves for C120, (CH3)20, C102 and S02 (Fig. 8) show two peaks, the positions of the... 

Fig. 8.—Radial distribution curves for chlorine monoxide, dimethyl ether, chlorine dioxide.and sulfur dioxide.

This compound, which contains atoms arranged tetrahedrally around the boron atom, can readily be isolated from a mixture of dimethyl ether and boron trichloride. On occasions a chlorine atom, in spite of its high election affinity, will donate an electron pair, an example being found in the dimerisation of gaseous monomeric aluminium chloride to give the more stable Al2Clg in which each aluminium has a tetrahedral configuration ... 

In the first of these, the key step in the synthetic sequence involves an oxidative phenol coupling reaction patterned after the biosynthesis of the natural product. Preparation of the moiety that is to become the aromatic ring starts by methyla-tion of phloroglucinol (5) with methanolic hydrogen chloride to give the dimethyl ether (6). Treatment of that intermediate with sulfuryl chloride introduces the chlorine atom needed in the final product (7). 

Other phosphonic dichlorides (45), (46) have been obtained from phosphorodi-chloridites and chlorinated dimethyl ethers.39... 

Photolytic. Methyl formate, formed from the irradiation of dimethyl ether in the presence of chlorine, degraded to carbon dioxide, water, and small amounts of formic acid. Continued irradiation degraded formic acid to carbon dioxide, water, and hydrogen chloride (Kallos and Tou, 1977 Good et al, 1999). 

Kallos, G.J. and Tou, J.C. Study of photolytic oxidation and chlorination reactions of dimethyl ether and chlorine in ambient air. Environ. Sci Technol, 11(12) 1101-1105, 1977. 

The properties of the ethers may be summarized hy (ltvvilh the exception of dimethyl ether which is a gas. die ethers arc volatile, mobile, inflammable liquids that are lighter than H O 121 they are relatively inert chemically, not being acted on by alkali metals or alkalis and not reacting with dilute acids (31 they form substitution producls when reacted wiih chlorine and bromine and (4t they decompose when healed with strong acids, yielding esters. 

Chloromethane can be produced by either chlorination of methane or reaction of methanol with hydrogen chloride. In an integrated production of silicones hydrogen chloride obtained by hydrolysis of methylchlorosilanes is recycled to the Direct Process via a chloromethane synthesis. The losses are compensated by make-up chloromethane or hydrogenchloride. Impurities, tike water, methanol, dimethyl ether or oxygen, must be kept at as low a level as possible. 

Ethanol, C2H6O, has covalent bonds and is a liquid at room temperature. Ethanol bods at a temperature 44° higher than dimethyl ether, which has the same formula but a different arrangement of atoms. The difference in boiling point occurs because ethanol is a polar molecule whereas dimethyl ether is less polar. Chlorine, CI2, is the most nonpolar of the substances shown in Figure 9.26 because the bond between the two chlorines is completely covalent and, therefore, nonpolar. Interactions between chlorine molecules are minimal, so chlorine is a gas at room temperature. 

Alkylation of dihydroorcinol dimethyl ether (F) with E gave G. Chlorination of G with N-chlorosuccinimide provided H, which was aromatized by dehydrochlorination to give I. Introduction of a formyl equivalent to I furnished J, whose acid treatment gave (-)-ascochlorin (136) as crystals.26... 

Bonds to Chlorine.— The reaction between PCI3 and an excess of methanol in the cold has been reinvestigated, to show that more than two moles of HCl are liberated dimethyl ether can also be detected as a product, but there is no evidence for the phosphonate MePO(OMe)2. A mechanism based on the dealkylation of the assumed intermediate P(OMe)3 has been postulated to account for these observations. Eutectics only are found in the PCl3-TeCl4 and AsCli-TeCU systems, but with POCI3 an incongruently melting 1 1 adduct is formed.Modification of silica surfaces to incorporate Cr" -P -0 layers can be achieved by successive treatment with chromyl chloride and phosphorus trichloride. 

If dimethyl ether is to be further chlorinated it has been recommended518 that dimethyl ether and chlorine should be passed simultaneously into previously prepared, liquid chloro-methyl methyl ether with water-cooling (condenser in the liquid) and under intense UV irradiation to avoid explosions the reaction must be carried out under N2 until considerable amounts of HC1 are being evolved. 

PVC is affected (either dissolves completely or substantially) by the following solvents aeetyl nitrile, acetone, chlorine (gas), cyclohexanone, diethylene gly-eol dimethyl ether, difluoromonochloromethane, dimethylformamide, methyl ethyl ketone, methylene chloride, monoethylene glycol dimethyl ether, monofluo-rodiehloromethane, tetraethylene glycol dimethyl ether, tetrahydrofiiran, and triethylene glyeol dimethyl ether. 

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