Propane, 2,2'-[methylenebis(oxy)]bis[1,1,1,3,3,3-hexafluoro-

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 300 ml reactor, which had been cooled down in dry ice/acetone bath to -20° C., was charged with 111.3 g of fuming sulfuric acid, 9.3 g of paraformaldehyde and 52.8 g of HFIPA, followed by stirring for 20 minutes. After stopping stirring, it was cooled down to room temperature by standing still. With this, the contents were separated into two layers. The organic matter of the upper layer was taken out and then washed with 50 ml of 5% sodium hydrogencarbonate aqueous solution. With this, it was separated into two layers to obtain an organic matter. After stopping stirring With this, the contents were separated into two layers washed with 50 ml of 5% sodium hydrogencarbonate aqueous solution With this, it was separated into two layers to obtain an organic matter

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: U.S. Pat. No. 6,100,434 describes the synthesis of sevoflurane through the preparation of sevochlorane and subsequent fluorination of this intermediate with potassium fluoride in a high molecular weight solvent. Sevochlorane is prepared from hexafluoroisopropanol, aluminum trichloride and 1,3,5-trioxane. An excess of aluminum trichloride in the reaction medium results predominantly in the formation of 2,2′-[methylenebis(oxy)]bis-(1,1,1,3,3,3-hexafluoropropane)—hereinafter denominated P1. The reaction is interrupted by addition of a 6N HCl solution to decompose the gel of hydroxydichloroaluminate. The authors relate that the isolated product contained 95% sevochlorane, <5% of P1 and <1% of polyacetals of higher molecular weight. The crude yield described was 87%. Among the disadvantages of this process is the fact that large quantities of aluminum trichloride must be handled, which is a highly hygroscopic solid and whose reaction with atmospheric humidity or with residual water present tends to be violent. The fact that this reagent easily reacts with water, resulting in the formation of acidic gasses, causes a reduction in its content, compromising considerably the yield of the reaction and the purity of the isolated product. The addition of a 6N hydrochloric acid solution to interrupt the reaction is an additional disadvantage of the process, violently elevating the reaction temperature, resulting in partial product loss by decomposition, volatilization and polymerization. Finally, this reaction generates as a residue, an aqueous phase containing hydroxyaluminates that require incineration for disposal, incurring additional costs.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: U.S. Pat. No. 6,100,434 describes the synthesis of sevoflurane through the preparation of sevochlorane and subsequent fluorination of this intermediate with potassium fluoride in a high molecular weight solvent. Sevochlorane is prepared from hexafluoroisopropanol, aluminum trichloride and 1,3,5-trioxane. An excess of aluminum trichloride in the reaction medium results predominantly in the formation of 2,2′-[methylenebis(oxy)]bis-(1,1,1,3,3,3-hexafluoropropane)—hereinafter denominated P1. The reaction is interrupted by addition of a 6N HCl solution to decompose the gel of hydroxydichloroaluminate. The authors relate that the isolated product contained 95% sevochlorane, <5% of P1 and <1% of higher molecular weight polyacetals. The crude yield described was 87%. Among the disadvantages of this process is the fact that large quantities of aluminum trichloride must be handled, which is a highly hygroscopic solid and whose reaction with atmospheric humidity or with residual water present tends to be violent. The fact that this reagent easily reacts with water, resulting in the formation of acidic gasses, causes a reduction in its content, compromising considerably the yield of the reaction and the purity of the isolated product. The addition of 6N hydrochloric acid to interrupt the reaction is an additional disadvantage of the process, violently elevating the reaction temperature, resulting in partial product loss by decomposition, volatilization and polymerization. Finally, this reaction generates as a residue, an aqueous phase containing hydroxyaluminates that require incineration for disposal, incurring additional costs.