Selective production of di¯uoromethyl methyl ether from chlorodi¯uoromethane using alkali metal carbonates Hyunjoo Lee a , Hoon Sik Kim a , Sang Deuk Lee a , Won Koo Lee b , Honggon Kim a,* a CFC Alternatives Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongrayng, Seoul 136-791, South Korea b Department of Chemistry, Sogang University, Seoul 121-742, South Korea Received 28 July 2000; accepted 29 September 2000 Abstract CHF 2 OCH 3 (HFE-152a), an important starting material for synthesizing various C 2 hydro¯uoroethers and a prospective alternative to CH 3 CF 2 Cl (HCFC-142b), has been found to be effectively produced from the reaction of CHF 2 Cl (HCFC-22) with alkali metal carbonates in methanol. Some alkali metal carbonates induce selective production of CHF 2 OCH 3 with a small amount of CH(OCH 3 ) 3 , a major side product. Activities of alkali metal carbonates for producing CHF 2 OCH 3 are in the order of K 2 CO 3 > Na 2 CO 3 > Li 2 CO 3 , suggesting that the solubility and ionization tendency of alkali metal carbonate in methanol play important roles in the reaction. # 2001 Elsevier Science B.V. All rights reserved. Keywords: Hydro¯uoroether; Di¯uoromethyl methyl ether; Chlorodi¯uoromethane; Alkali metal carbonate 1. Introduction Hydro¯uoroethers (HFEs) are prospective candidates for next generation alternatives of CFCs (chloro¯uorocarbons) because HFEs do not produce ozone depletion and these have very low impact on global warming [1±3]. Several theoretical and experimental reports proposed that some HFEs such as CHF 2 OCHF 2 , CF 3 OCH 3 , CF 3 CF 2 OCH 3 , and CF 3 CF 2 CF 2 OCH 3 have favorable physical and chemical properties as do CFCs, HCFCs (hydrochloro¯uorocarbons) and HFCs (hydro¯uorocarbons) [4±6]. Di¯uoromethyl methyl ether (CHF 2 OCH 3 , HFE-152a) is considered a useful starting material for synthesizing various higher-¯uorinated dimethyl ethers [7] and a possible alter- native refrigerant to CH 3 CF 2 Cl (HCFC-142b) [8]. It has been reported that CHF 2 OCH 3 can be synthesized by the reaction of CHF 2 Cl and CH 3 ONa in which, however, a large amount of trimethylorthoformate, CH(OCH 3 ) 3 , is produced as a side product which is, however, economically valueless [8±10]. Formation of CH(OCH 3 ) 3 requires competitive con- sumption of the reactants, CHF 2 Cl and CH 3 ONa. In other words, the formation of CH(OCH 3 ) 3 inevitably reduces the yield of CHF 2 OCH 3 . In this paper, we report a method to suppress effectively the formation of the side product, CH(OCH 3 ) 3 by employing alkali metal carbonates instead of using CH 3 ONa as a base. 2. Experimental CHF 2 Cl (purity > 98%) was supplied from Ulsan Che- mical Co. Methyl alcohol, sodium methoxide, alkali metal carbonates and other reagents used were purchased from Aldrich Chemical Co. All chemicals were used without further puri®cation. Reactions were conducted in a 100 ml stainless steel high- pressure reactor with a magnetic drive stirrer and an elec- trical heating jacket. Base (50 mmol), methanol (25 ml) and ethylene glycol dimethyl ether (1 g, internal standard) were charged into the reactor. After the mixture was cooled to 58C with a vigorous stirring, CHF 2 Cl (200 mmol) was fed to the reactor through a sampling valve. The reactor was then heated to a reaction temperature and the reactants were stirred for 2 h. After cooling the reaction mixture to ± 788C, a sample of the liquid phase was analyzed using GC (HP 6890, HP-1, 50 m  0:2 mm  10 um). The formation of CHF 2 OCH 3 was con®rmed by GC-Mass (HP 6890-5973 MSD) and 19 F NMR (564.54MHz, Varian INOVA-600) [11]. Journal of Fluorine Chemistry 107 (2001) 133±136 * Corresponding author. Tel.: 82-2-958-5858; fax: 82-2-958-5859. E-mail address: hkim@kist.re.kr (H. Kim). 0022-1139/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0022-1139(00)00392-4