GB692279A - Method of making chloromethyl methyl ether - Google Patents

Abstract

Chloromethyl methyl ether is obtained by introducing hydrogen chloride into an aqueous mixture containing approximately molecular equivalent proportions of formaldehyde and methyl alcohol in admixture with calcium chloride in amount corresponding approximately to from 0.5 to 1 part by weight of the calcium chloride (based on the anhydrous salt) per part of the water to be present upon completion of the reaction, at a reaction temperature between 0 DEG and 60 DEG C., until the mixture is substantially saturated with respect to the hydrogen chloride and thereafter separating the chloromethyl methyl ether from the reaction mixture. The formaldehyde is preferably employed in the form of an aqueous solution containing from 27 to 40 per cent by weight or more of formaldehyde. although formaldehyde in solid or polymeric form such as paraformaldehyde or trioxan may be used. The calcium chloride may be employed in amount sufficient to form a saturated or nearly saturated solution of the calcium chloride in the aqueous medium and the reaction is usually effected at 10-50 DEG C. and at substantially atmospheric pressure, although lower or higher pressures, e.g. from 5 to 20 pounds per square inch may be used. In examples: (1) hydrogen chloride is passed into a mixture of methyl alcohol, an aqueous formaldehyde solution, and calcium chloride (containing water of crystallization) maintained at 40-50 DEG C., chloromethyl methyl ether being obtained from the organic layer; in a comparative example in which the calcium chloride is omitted a reduced yield of the product is obtained; (2) a mixture of methyl alcohol, paraformaldehyde, and calcium chloride (containing water of crystallization) is stirred and heated to 40 DEG C. and a stream of hydrogen chloride is then introduced, chloromethyl methyl ether being recovered from the organic layer; (3) as in (1) except that the reaction mixture is maintained at 10 DEG C.; in a comparative example the reaction is effected under similar conditions but in the absence of calcium chloride the product being obtained in reduced yield.